# Powering subwoofer - need some clarification.



## selway89 (Aug 17, 2009)

Hi all, just posting to pick some of your brains 

I currently have a fairly nice sound system for my pc:
Creative X-Fi XtremeMusic into a Mission Cyrus One amp, driving some Mission M30i speakers.

However I want to add a bit more low end uumff. My old amp (Teac CR-H100) did power a Bose accoustimass subwoofer of my dads but thats back in its box ready for eBay 

My query is will my Teac amp which is 20W per channel and can drive 6 to 16ohm speakers be ok to power a mono 3ohm sub? Thinking of this cheap sub: http://cgi.ebay.co.uk/ws/eBayISAPI....71859&ssPageName=STRK:MEWAX:IT#ht_1392wt_1165 or this one http://cgi.ebay.co.uk/ws/eBayISAPI....gory=14996&ssPageName=WDVW&rd=1#ht_1281wt_907

Obviously I'd like to make sure that audio from both Left and Right channels go to the sub so I were thinking if I wire the Left and Right outputs into the single input be ok?







The Teac amp will be fed from the headphone out on the Cyrus and this works fine and allows me the option to control the sub volume or to turn it off completely, worked great with the Bose.

Any info and help will be greatly appreciated.


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## Frederik S (Aug 17, 2009)

It might work, but it will most likely either sound like crap since the amp is made for a normal load or blow a fuse in the TEAC since it isn't made for extremely low impedance loads like a real sub.

And the BOSE Acoustimass wasn't I believe a real sub but just a bass driver put in a sub like cabinet. Normal impedance made for systems with no pre sub or sub out.


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## selway89 (Aug 17, 2009)

Hmm I were thinking along the lines that with the output from the amp shared then the current draw won't blow the amp. The Bose acts just like any other passive sub with a built in crossover and gave great results. Just hoping to emulate it on the cheap.

If not then maybe something like this might be worth the extra cash http://cgi.ebay.co.uk/LTC-ACTIVE-HO...5a2fdb31a&_trksid=p3286.c0.m14#ht_5360wt_1165


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## pantherx12 (Aug 17, 2009)

I'd say go for a better amp and sub anyways.

100 watts of bass is so much sweeter to the ears


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## dr emulator (madmax) (Aug 17, 2009)

selway89 said:


> Hi all, just posting to pick some of your brains
> 
> I currently have a fairly nice sound system for my pc:
> Creative X-Fi XtremeMusic into a Mission Cyrus One amp, driving some Mission M30i speakers.
> ...


yikes no it doesn't work like that i'll see if i can find a small but easy to do/understand diagram for you (may take some time to root one out) 
	

	
	
		
		

		
		
	


	



:edit:
oh and i'd have to agree with pantherx12 it'd be better if you did get something proper


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## selway89 (Aug 17, 2009)

Thought it might not be the right way to do it. http://cgi.ebay.co.uk/ELTAX-SW20-Su...3ca4d45bbf&_trksid=p3286.c0.m14#ht_600wt_1165 That seems a bit more powerful. Thing is where would I take the signal from to the line in? Tape out on the Cyrus amp doesn't change volume with speaker volume, would using the headphone out be fine?


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## Wile E (Aug 17, 2009)

selway89 said:


> Hi all, just posting to pick some of your brains
> 
> I currently have a fairly nice sound system for my pc:
> Creative X-Fi XtremeMusic into a Mission Cyrus One amp, driving some Mission M30i speakers.
> ...


Wiring a 3ohm sub into both channels in parallel like that will result in a 1.5ohm load. Much too low for that amp. You would need a single sub of 12ohm to wire it like that, or 2 3ohm subs wired in series per channel would also give you 6ohms per channel.


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## MKmods (Aug 17, 2009)

I dont have any time now to explain properly but here is a simple guide
http://www.diyaudioandvideo.com/FAQ/Wiring/

If you try to run a home amp thats made for 6-16ohm less (like 3ohm) it will overdrive the amp and overheat possibly fry it...


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## Wile E (Aug 17, 2009)

Overall, I'd say you're better off with a powered sub that has speaker level inputs.


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## selway89 (Aug 17, 2009)

Cheers all, thinking about it, it now seems like a daft idea. My brain isn't functioning too well tonight 

Think something like those eltax ones might be more than enough for my needs. That eltax one I'v linked is the kinda price I want to pay. Using the headphone out will be ok for the sub line in shouldn't it?


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## Wile E (Aug 17, 2009)

selway89 said:


> Cheers all, thinking about it, it now seems like a daft idea. My brain isn't functioning too well tonight
> 
> Think something like those eltax ones might be more than enough for my needs. That eltax one I'v linked is the kinda price I want to pay. Using the headphone out will be ok for the sub line in shouldn't it?



Only if the sub has it's own crossover built in.


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## selway89 (Aug 17, 2009)

One im looking at has crossover adjustment and volume....
http://cgi.ebay.co.uk/ELTAX-SW20-Su...3ca4d45bbf&_trksid=p3286.c0.m14#ht_600wt_1165


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## Steevo (Aug 18, 2009)

I built some great boxes based on Bose technology, just get a good transformer out of a old stereo and a couple caps and use a car amp. Wire it up and you have a kicking sub for less than $50


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## selway89 (Aug 18, 2009)

Steevo said:


> I built some great boxes based on Bose technology, just get a good transformer out of a old stereo and a couple caps and use a car amp. Wire it up and you have a kicking sub for less than $50



Like the idea! Unfortunately my dad won't let me use the bose sub. Think I'll go with that eltax or something similar. Give it line out from headphone on Cyrus amp and set the crossover and volume. Hopefully give me a bit more bottom end than the tiny M30i's which is surprising for their size. Always nice to have a bit more to annoy the flat mates with when I go back to uni in sept


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## pantherx12 (Aug 18, 2009)

You could buy a speaker : ]

You can get a 150 watt speaker for about 30 quid if you look in the right places

( places that I can't remember at the moment but I'll look for you in the morning)

And you can get 180 watt amps for 15 quid of ebay ( the blue ones, they work really well actually)

All they need is a 12v power supply ( and above 1 amp, 2-5 amps ideally, but they will run of 12 1 amp, they just won't go as loud)


Then its just a case of finding some MDF, cutting holes sticking together etc, its not to much harder then building a pc to be honest, if you have the right tools.


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## dr emulator (madmax) (Aug 18, 2009)

if you are still planning doing it yourself here's a simple circuit that i came across on my cd/tape player


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## dr emulator (madmax) (Aug 18, 2009)

hm here's how it should look 
	

	
	
		
		

		
		
	


	



hey what did you expect a picasso it's 1.28am

oh yes that circuit would maybe need slightly refining on a powerfuller output and would also require a powered subwoofer


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## selway89 (Aug 18, 2009)

Cheers for that, interested to see what panther comes up with for me. If it can be driven by my Teac amp then all the better to lower cost.


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## pantherx12 (Aug 18, 2009)

Found the website sooner then I thought!

Heres a couple that may interest you

http://www.terralec.co.uk/loudspeaker_parts/high_power_bass_woofer_10_25cm/25864_p.html

http://www.terralec.co.uk/loudspeaker_parts/12__200_watt_loudspeaker/18854_p.html

There's loads on the site though ( those two are probably a bit over kill actually but hey, there cheap! ha ha can always upgrade amp later)

you may also find this interesting http://www.loudspeakerdesign.co.uk/ : ]

If you do decide to build your own speaker good luck and I hope you find it fun 

The best thing is if you do a okay job, it will outperform a retail speaker of about 3-4 times the price.

Enjoy


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## strick94u (Aug 18, 2009)

dr emulator (madmax) said:


> if you are still planning doing it yourself here's a simple circuit that i came across on my cd/tape player
> 
> http://img.techpowerup.org/090817/simple sub out.jpg


 a speaker with 2.6k ohm damn! thats almost 3000 ohms what are we trying to do here 
if the guy is trying to build his own system they do make amps that work on 2ohms speakers 
you can buy them at the guitar store id go for a set of black widows fired buy a nice glass tube amp. or save some money and buy a set of computer speakers with a decent sub


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## temp02 (Aug 18, 2009)

I'm not an expert in electronics but since the output already comes from an amplifier, to avoid loosing power/dBs wouldn't it be better if you use this setup:




This way you will _only_ (mostly) play the common sounds on the left and right speakers, _ruling out_ (almost) sounds that are common to just one speaker (aka stereo to mono passive crossover).

*EDIT:* Found some info to back up my theory at this page.
Also on this page there is an extra circuit that with the help of some coils and capacitors try to reduce the noise generated by the extra speaker (sub) on the remaining speakers.


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## KH0UJ (Aug 18, 2009)

selway89 said:


> Hi all, just posting to pick some of your brains
> 
> I currently have a fairly nice sound system for my pc:
> Creative X-Fi XtremeMusic into a Mission Cyrus One amp, driving some Mission M30i speakers.
> ...



I think it can still power your sub speaker assuming its a double voice coil sub speaker, it can make the power amp. circuit a little hotter though, add some fans on the power amp. heatsinks then you`ll be alright lower resistance speaker coils can emit higher inductive feedback on the amps, that`s why it gets hotter fast, but great low freaquency bass response  I also used sub on my PC  8 inch 300 Watts 4 ohm DVC powered by 1 400 watts RMS mono amp that ived assembled myself (1 ohm stable circuit) and tuned the speaker box to 30 HZ, im happy with it



edit: oopps! im looking at your picture drawn you cant put together the left output and right output together bro assuming its a line-to-line amp, even the negative terminals cannot be put together because of the split supply (+ ground -) system, unless its a common ground power supply circuit
you can just install the two outputs if your speaker is a double voice coil, in that way they are isolated to each other (left & right speaker terminals)


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## Wile E (Aug 18, 2009)

temp02 said:


> I'm not an expert in electronics but since the output already comes from an amplifier, to avoid loosing power/dBs wouldn't it be better if you use this setup:
> http://forums.techpowerup.com/attachment.php?attachmentid=27761&stc=1&d=1250563569
> This way you will _only_ (mostly) play the common sounds on the left and right speakers, _ruling out_ (almost) sounds that are common to just one speaker (aka stereo to mono passive crossover).
> 
> ...


That's only if the amp supports bridging. I doubt a run of the mill stereo receiver is capable of that.

Regardless, with a 3ohm speaker, he's still going to be looking at a 1.5ohm impedance per channel with that setup. The receiver is only rated for 6ohms per channel. His amp will fry with that kind of load. I would attempt 4 ohms/channel happily on that receiver, but not 1.5.


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## temp02 (Aug 18, 2009)

Yes you are right *Wile E*, I just assumed that the extra impedance needed was easy to cope with (at least to me it is, like adding an extra speaker in serial to each channel).


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## KH0UJ (Aug 18, 2009)

If you really wanna utilize your existing amp. and sub, buy a matching transformer which is rated 60 Watts, that would bridge your 2 amps together without compromising the  stereo amplifier, same like processors X2 is more powerful than X1


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## KH0UJ (Aug 18, 2009)

dr emulator (madmax) said:


> hm here's how it should look http://img.techpowerup.org/090817/amp.jpg
> hey what did you expect a picasso it's 1.28am
> 
> oh yes that circuit would maybe need slightly refining on a powerfuller output and would also require a powered subwoofer



No offense bro but the additional capacitor in series with the 2.6 Kilo ohms resistor will not sound the sub the way it should be, i think you can only hear 1% of the high frequency sound on it even if you full the volume of a 1000 watt rms amp. no bass, no mid, 2.6K is so high that it limits the current of the output which is needed on the low frequency response of a typical sub.


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## selway89 (Aug 18, 2009)

Thanks for all the info! Greatly appreciated. Building my own box is very appealing. 

I think one of these drivers http://cgi.ebay.co.uk/ws/eBayISAPI....159524&ssPageName=STRK:MEWAX:IT#ht_5014wt_939 which is from a Mission M6AS subwoofer http://www.hifix.co.uk/sku2.lasso?item=8e033768313ac87ade763a625a8743c2 in a simple infinite baffle 30L cab might do the job. 
The speaker it's self is 8ohm so fine for my amp on a single channel, should just be a case of converting the stereo signal to mono before the amp, possibly the need for a simple crossover circuit to tune the cutoff range.

edit. the reason why I chose the mission driver is mainly due to the fact my main speakers are mission and may provide to be a better match, also not overly keen on car based speakers.


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## KH0UJ (Aug 18, 2009)

selway89 said:


> Thanks for all the info! Greatly appreciated. Building my own box is very appealing.
> 
> I think one of these drivers http://cgi.ebay.co.uk/ws/eBayISAPI....159524&ssPageName=STRK:MEWAX:IT#ht_5014wt_939 which is from a Mission M6AS subwoofer http://www.hifix.co.uk/sku2.lasso?item=8e033768313ac87ade763a625a8743c2 in a simple infinite baffle 30L cab might do the job.
> The speaker it's self is 8ohm so fine for my amp on a single channel, should just be a case of converting the stereo signal to mono before the amp.



what is really your target frequency on your sound system bro?

cause what i understand on sub woofer frequency is from 10 hz to 60 hz and it can only be heard or be precisely produced if you`re using a low impedance speaker (1 ohm-4 ohms) 8 ohms speakers can also produce that frequencies but the intensity of the 30 Hz sound output on a 4 ohms speaker is louder than 8 ohms.


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## selway89 (Aug 18, 2009)

The M30i speakers have response of 68-20000Hz so just want to get the lower end of the scale. Just to enhance movies films and games, if it works like the bose did when I had that working then that will be fantastic.
Overall volume isn't a huge concern as it will be working with the Cyrus amp around 25W per channel.


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## KH0UJ (Aug 18, 2009)

how about a double voice coil speaker which is 8 ohms + 8 ohms 10 inches in diameter 60 watts, if you can make the box by yourself i can give you dimensions and ways on how to tune it using only your amp and a 33 Hz mp3 reference signal and play it on your computer in loop while tuning the tuning ports to achieve optimum intensity.


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## selway89 (Aug 18, 2009)

KH0UJ said:


> how about a double voice coil speaker which is 8 ohms + 8 ohms 10 inches in diameter 60 watts, if you can make the box by yourself i can give you dimensions and ways on how to tune it using only your amp and a 33 Hz mp3 reference signal and play it on your computer in loop while tuning the tuning ports to achieve optimum intensity.



Fantastic, sounds good. Open to ideas.


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## KH0UJ (Aug 18, 2009)

selway89 said:


> The M30i speakers have response of 68-20000Hz so just want to get the lower end of the scale. Just to enhance movies films and games, if it works like the bose did when I had that working then that will be fantastic.
> Overall volume isn't a huge concern as it will be working with the Cyrus amp around 25W per channel.



so its not a sub frequency, it`s a mid bass which is really easy to calibrate a tip also on the speaker selection, dont buy a speaker which is way too much wattage capacity, its just a waste of $, your amp is only 25 Watts, a 30 watts speaker capacity can do the job and is more cheaper than the higher watt capacity speakers, same like a PSU on a PC, if your PC only consumes 250W,  a 300w or 450w can do the job for a cheaper than buying 700 Watts.


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## selway89 (Aug 18, 2009)

True, only reason why I selected that Mission model is that it's easy to get hold of, should be easily driven from my amp, and the subwoofer produced by mission has a given spec of 30L infinite baffle cab which will be easy to make.

Found this too on my searches http://diyaudioprojects.com/Speakers/MAW-10/MAW-10.htm how relevant that cab is to the mission speaker I'm unsure but overall product looks great 

Have my 5th star too now


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## KH0UJ (Aug 18, 2009)

selway89 said:


> Fantastic, sounds good. Open to ideas.



alright then let me draw first all the dimensions, procedures, and everything maybe ill post it tomorrow, this is one of my ways to make my stars go up right now its only 4 stars

Moderators: can i post a PC sound system construction procedure here on TPU? i mean its still computer related topic cause its for PC


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## KH0UJ (Aug 18, 2009)

now im confused, hehehe, (not reading thoroughly while posting habit LOL) http://www.hifix.co.uk/sku2.lasso?item=8e033768313ac87ade763a625a8743c2
according to that link you`ved given its an active sub-woofer system, im puzzled LOL


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## selway89 (Aug 18, 2009)

Yes it is, idea is to build an infinite baffle 30L cab with that mission speaker. Rather than having it powered internally I should be able to use my Teac amp with the speaker rated at 8ohm which effectively is the same.


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## KH0UJ (Aug 18, 2009)

selway89 said:


> Yes it is, idea is to build an infinite baffle 30L cab with that mission speaker. Rather than having it powered internally I should be able to use my Teac amp with the speaker rated at 8ohm which effectively is the same.



so you mean to say you wanna buy the M6AS subwoofer system and condemn the active amp. and use your teac amp? im totally confused bro, kindly elaborate


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## selway89 (Aug 18, 2009)

Haha nah, effectively re-create the M6AS sub by building my own 30L box, and putting the Mission driver in it. http://cgi.ebay.co.uk/ws/eBayISAPI....159524&ssPageName=STRK:MEWAX:IT#ht_5014wt_939


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## KH0UJ (Aug 18, 2009)

selway89 said:


> Haha nah, effectively re-create the M6AS sub by building my own 30L box, and putting the Mission driver in it. http://cgi.ebay.co.uk/ws/eBayISAPI....159524&ssPageName=STRK:MEWAX:IT#ht_5014wt_939



AHH OK sorry for the confusion bro stupid me, now let`s get back to the topic, Dimensions (HxWxD) in mm. 500x320x430, that`s your dimensions right?


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## selway89 (Aug 18, 2009)

That size is for the M6AS as a whole. Just need a 30L (1.05ft3) cab so for a infinite baffle something like 12"x12"x12" should be plenty I think. Or I could use the dimensions from this http://diyaudioprojects.com/Speakers/MAW-10/MAW-10.htm and make it a ported cab.


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## dr emulator (madmax) (Aug 18, 2009)

strick94u said:


> a speaker with 2.6k ohm damn! thats almost 3000 ohms what are we trying to do here
> if the guy is trying to build his own system they do make amps that work on 2ohms speakers
> you can buy them at the guitar store id go for a set of black widows fired buy a nice glass tube amp. or save some money and buy a set of computer speakers with a decent sub



yes but he was buying a powered sub so ohmage is not to much of a concern hm yes capacitors well it was 1:30 am did you expect a rembrandt  oh and that circuit was out of a 20watt system minus caps : dam if it'd been a few months earlier he could have had my sony subwoofer for free as it was to big (was given away to a charity shop i think)


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## KH0UJ (Aug 18, 2009)

selway89 said:


> That size is for the M6AS as a whole. Just need a 30L (1.05ft3) cab so for a infinite baffle something like 12"x12"x12" should be plenty I think. Or I could use the dimensions from this http://diyaudioprojects.com/Speakers/MAW-10/MAW-10.htm and make it a ported cab.



12"X12"X12" can accomodate a nice response on a mid bass frequency, but if you prefer a slightly intensed bass production, go for a ported type on the MAW-10 dimensions, just replace the square tuning pipes with a PVC 3" in that way its easy for you to tune it, but i think you only need 8"inch long by 3"inch in diameter to begin with on both sides cause its 68 HZ you are tuning. slowly cut it by 1"inch each and every tune you made, set the volume on your amp. to half while calibrating the maximum intensity of the bass, the only problem is you need a signal generator software on PC to produce 68 HZ, i have it the last time, it`s a  trial version but it works just for tuning though


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## selway89 (Aug 18, 2009)

I were thinking that the MAW-10 looked like a good template for the mission driver. The good thing with the reflex port is I could tune it slightly as you say and the distance from a wall could also adjust how it sounds.

That design takes into account the driver size (wont be exactly same) and the plate amp, but I could make it an inch or two shorter, but then again I'v read cabs slightly bigger than required help with the lower end.

Off to the garage to see what wood there is laying around. 

Id like to thank all for their help.


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## KH0UJ (Aug 18, 2009)

Ived just found the signal generator freeware, http://www.brothersoft.com/mini-signal-generator-160327.html , just run it and type 68 HZ on the frequency sinewave then press save to and set it to 5 minutes so that its longer .wav file enough for you to tune and cut, may the modding force be with you and good luck on your construction


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## KH0UJ (Aug 18, 2009)

ohh i almost forgot, about the Db meter, just do it the conventional way, set the volume to halfway, play the 68 HZ sinewave .wav file, position the box and listen to it 30 feet away, i know its not accurate but its a quick calibration, but if you prefer the high tech way, you need a laptop with mic and download this http://www.softpedia.com/progDownload/Zelscope-Download-89785.html , (Zelscope 1.00) its a PC oscilloscope using the mic as a sensor, in that way you are sure about the intensity you are measuring, its a trial version though but mine`s fullware hehehe, put it 10 feet apart from the soundbox you are tuning, and put it steady and also the volume of the amp while seeing the different intensities of each cut.


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## pantherx12 (Aug 18, 2009)

Didn't know there was so many people into speakers on here 

I had to do it all on my lonesome : [

Your speakers are going to be grand.

Makes me want to buy 8 speakers ( 2 subs 2 tweeters and 4 mids) and build two cabinets he he he


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## selway89 (Aug 18, 2009)

Haha. I think a audio sub forum should be somewhere, there are a couple of threads dedicated to audio but nowhere really for them.

For my first attempt I'll be putting that mahoosive mission 10" sub in a 12"x12"x12" infinite reflex cab to see how it sounds, and then maybe attempt a reflex ported cab.

Hopefully go well with my Mission m30s


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## KH0UJ (Aug 18, 2009)

I have one tip also in building enclosure for subs the idea is to fool human`s hearing ability with a massive harmonic frequency generated by the enclosure, that`s why you wonder why some sound boxes sound so powerful than the others, the 12"X12"X12" is just fine, but if you wanna design it to have a massive harmonic frequency for me 12"X12"X40" and make a ported tube pipe at the back of the enclosure, mine is 10"X10"X20" 

here`s the pic of my modified sub right now im living on a company barracks, my room`s ugly bro


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## selway89 (Aug 18, 2009)

Looks rather beefy! I'll stick to the 12x12x12 for now as a test, and see how it goes, plus space will be abit tight when I go back to uni in sept. But I'll make it an on-going project (like most things)


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## KH0UJ (Aug 18, 2009)

I have an experience before on small enclosure subs and im not satified with the amount of intensity to think its a 15"inch Kicker 800W capacity after I made an enclosure by myself (18"X18"X35") ported 3" pipe at the back 33 HZ, the enclosure belongs to my co-worker and he`s shocked with the intensity after I installed back to his car it is space consuming but he`s satisfied with the audio bass intensity, it`s my part time before way back on my college days bro and i made some money out of it to support my college course well those were the days here`s the picture of his junked enclosure, sorry for the mess but it did its purpose 






here is the link on ebay 

http://cgi.ebay.com/NEW-KICKER-07VCVR122-SINGLE-15"-800W-WOOFER_W0QQitemZ280361501516QQcmdZViewItem


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## Steevo (Aug 18, 2009)

I hate MDF on speakers, I use OSB for more strength. I have seen alot of boxes blown apart, and my 3/4" box with two 12" pioneer comp speakers is still going strong. Still oud enough to make your heart skip beats.


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## KH0UJ (Aug 18, 2009)

Steevo said:


> I hate MDF on speakers, I use OSB for more strength. I have seen alot of boxes blown apart, and my 3/4" box with two 12" pioneer comp speakers is still going strong. Still oud enough to make your heart skip beats.



 ya MDF sucks man, for me Ived used 1/2 ordinary plywood (not the marine, its so stiff it cannot flex and very hard to tune to a lower frequency 33 HZ  ) easier to tune cause of the flexibility, Ived put body filler on the edges of the inside of the enclosure and painted it heavily with wood enamel and used wood screws + epoxy on the joints, to have a stronger bond on the edges.


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## selway89 (Aug 19, 2009)

Ill be using 12mm ply. Nice and strong can be painted easily etc.


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## Wile E (Aug 19, 2009)

KH0UJ said:


> what is really your target frequency on your sound system bro?
> 
> cause what i understand on sub woofer frequency is from 10 hz to 60 hz and it can only be heard or be precisely produced if you`re using a low impedance speaker (1 ohm-4 ohms) 8 ohms speakers can also produce that frequencies but the intensity of the 30 Hz sound output on a 4 ohms speaker is louder than 8 ohms.



Actually, the impedance doesn't effect the frequency response.

As far as boxes, give me the flat response and low end extension of a sealed enclosure any day of the week. I hate the sound of ported and bandpass boxes. So muddy and dirty sounding.


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## KH0UJ (Aug 19, 2009)

Wile E said:


> Actually, the impedance doesn't effect the frequency response.
> 
> As far as boxes, give me the flat response and low end extension of a sealed enclosure any day of the week. I hate the sound of ported and bandpass boxes. So muddy and dirty sounding.



yes it does bro, ive been rewinding a lot of 8 ohm speakers way back then to convert it to 4 ohm and 2 ohms speaker set-up, if you try to look at the frequency response on a DB meter it differs greatly, the most intensified of them all is the 1 ohm speaker coil,  im talking about individual speaker itself, cause you can simply achieve lower resistances if you try to parallel them, like for example you want it to be 2 ohms impedance, just parallel the 2 pc. 4 ohms then you can have 2 ohms speaker configuration (ohm`s law), but if you try to compare it on a single 2 ohm speaker itself, it has really a great difference on the intensity and lower frequency production, a 2 ohm speaker can respond greatly even on a 10 HZ signal which the paralleled 2 pc. 4 ohm speaker cannot produce, i mean you cannot hear it anymore on the paralleled ones, it can only vibrate but the intensity is not there anymore 


Do an experimentation on 2 speakers with the same box and same volume level on the amp. but different resistances on the speakers itself, and try even the 60 HZ sine signal, try to swap the speakers (4 ohms and 8 ohms) with the same diameter, and hear which one is more intensified and can respond greatly on the lower frequencies


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## selway89 (Aug 19, 2009)

Im with Wile E hence going for the infinite baffle enclosure first. I think having something thats tuned to a super low frequency will be too boomy and ruin the already good sound from my Mission M30is, as I have mentioned before Im wanting to add the missing lower end that the small speakers cant easily produce. If its anything like my old Logitech Z4 sub then Ill be happy as that was a sealed enclosure sub.


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## KH0UJ (Aug 19, 2009)

selway89 said:


> Im with Wile E hence going for the infinite baffle enclosure first. I think having something thats tuned to a super low frequency will be too boomy and ruin the already good sound from my Mission M30is, as I have mentioned before Im wanting to add the missing lower end that the small speakers cant easily produce. If its anything like my old Logitech Z4 sub then Ill be happy as that was a sealed enclosure sub.



no probs bro i just wanna make my post count rising its almost 5 stars
ohh can i post one more topic?


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## KH0UJ (Aug 19, 2009)

There are two kinds of bass boomers as far as i know, the soft crawling bass boomers and the hard punching bass boomers, 

Soft crawling bass boomers usually likes hip-hop music, r&b, and disco, (mostly girls love this ), usually you can hear 

them already even on a quarter mile before they pass you, cause they`re set-up is calibrated on the lower frequencies which only a 

ported and a modified G-type can produce + higher wattage sub power amps.

Hard punching bass boomers usually likes rock n roll, heavy metal, and classic rock, they`re set-up is tuned for clarity on the 

instruments and heart pounding bass drums, low frequency speakers usually required on this system set-ups are the higher resistance 

speaker systems, prefered enclosure designs are the W-box, sealed type and the G-box which can produce hard bass frequencies, a 

couple of mid range speakers and high frequency speakers (tweeters) is a must for this set-up.




Some of my clients said that, hip-hop and rock n roll really dont mix too well , for me i guess its true cause if you play soft 

crawling bass on a hard punching set-up, it really doesn`t sound so well, i mean i cant hear the low frequency responding so well 

LOL, same as the rock n roll music played on a soft crawling bass set-up, I cant hear the mid and high frequency so clearly ,

I guess each set-ups are optimized for their own use, but for me, I like both to be honest  

and one more thing, my post counts are increasing already, i just wanna make it 5 stars then im happy


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## KH0UJ (Aug 19, 2009)

ok im done here bro thanks for the post count


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## ste2425 (Aug 19, 2009)

just looking at your pic of the wireing you will only need one black or nuetral wire but two live wires for left and right. Thats the way a pair of in ear headphones work. dont no what it will sound like, never done it, but in theory it should work. (having two live wires to make mono i mean).  (ive done the single neutral wire but ive always had to live as its been from a stereo device to a stereo device)


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## selway89 (Aug 19, 2009)

Yeh ste thats what I thought, but the load across my amp would be too low and burn it out, also dont think it is designed to be bridged on the outputs. Ill be doing that though from the headphone out on the Cyrus amp into a single mono phono connection and use one channel to power the 10" 8ohm sub.

ps. love that sig  capri mk2?


edit:

Also anyone got any ideas if I should have a front or downward firing cab? Will use floor spikes I would have thought to give it abit of clearance etc.


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## ste2425 (Aug 19, 2009)

selway89 said:


> ps. love that sig  capri mk2?
> 
> 
> edit:
> ...



well ive never had much experience with home speaker setups but im doing reocrding degree at uni and the monitors we use there mainly point upwards. Ive found them better oposed to the usual forwards pointing cabs.

and yes it is a mk2 capri


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## Wile E (Aug 19, 2009)

KH0UJ said:


> yes it does bro, ive been rewinding a lot of 8 ohm speakers way back then to convert it to 4 ohm and 2 ohms speaker set-up, if you try to look at the frequency response on a DB meter it differs greatly, the most intensified of them all is the 1 ohm speaker coil,  im talking about individual speaker itself, cause you can simply achieve lower resistances if you try to parallel them, like for example you want it to be 2 ohms impedance, just parallel the 2 pc. 4 ohms then you can have 2 ohms speaker configuration (ohm`s law), but if you try to compare it on a single 2 ohm speaker itself, it has really a great difference on the intensity and lower frequency production, a 2 ohm speaker can respond greatly even on a 10 HZ signal which the paralleled 2 pc. 4 ohm speaker cannot produce, i mean you cannot hear it anymore on the paralleled ones, it can only vibrate but the intensity is not there anymore
> 
> 
> Do an experimentation on 2 speakers with the same box and same volume level on the amp. but different resistances on the speakers itself, and try even the 60 HZ sine signal, try to swap the speakers (4 ohms and 8 ohms) with the same diameter, and hear which one is more intensified and can respond greatly on the lower frequencies


Yeah, but that's only when the speaker design doesn't account for the different impedance. If you are rewinding a 8ohm speaker to be 4ohms, of course the tonal characteristics are going to change, as it was designed with 8ohms in mind, and tuned as such. But, if a speaker is designed with a 4ohm and 8ohm models from the beginning, the tonal characteristic are identical between both models, as they are both tuned to sound the same. 

When rewinding a speaker, yes, you are correct. When purchasing a model of speaker that comes in a range of impedance choices, you are not correct, as the different impedances are already accounted for in design, and the different impedance speakers are made to tonally match.

Not only that, but you can't attribute all of the sonic changes to the speakers, some of that sonic difference will come from the different behavior of the amp at different impedances as well.

And I have tested the difference between 2 different impedance models of the same subs directly on numerous occasions. I used tune custom stereos in cars, some for spl comp, and some for sq comp.


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## KH0UJ (Aug 20, 2009)

Wile E said:


> Yeah, but that's only when the speaker design doesn't account for the different impedance. If you are rewinding a 8ohm speaker to be 4ohms, of course the tonal characteristics are going to change, as it was designed with 8ohms in mind, and tuned as such. But, if a speaker is designed with a 4ohm and 8ohm models from the beginning, the tonal characteristic are identical between both models, as they are both tuned to sound the same.
> 
> When rewinding a speaker, yes, you are correct. When purchasing a model of speaker that comes in a range of impedance choices, you are not correct, as the different impedances are already accounted for in design, and the different impedance speakers are made to tonally match.
> 
> ...



I guess we have both extensive experiences about sound system set-ups
maybe im wrong but i cannot find an 8 OHM speaker for sub to respond the 10 HZ-43 HZ last time no matter how i tuned the ported box, that`s why im just gonna utilize the owner`s current set-up than buying an expensive DVC 4 OHM speaker (2 ohms paralleled) and rewind it to a single 2 OHM speakers, maybe it depends on what`s our sub-woofer target frequency design, cause im basing it on my custom active 4rth order low-pass filter circuit (custom cross over) which is 10 HZ to 43 HZ and i find the 2 OHMS speaker has a great response on my DB meter


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## strick94u (Aug 20, 2009)

dr emulator (madmax) said:


> yes but he was buying a powered sub so ohmage is not to much of a concern hm yes capacitors well it was 1:30 am did you expect a rembrandt  oh and that circuit was out of a 20watt system minus caps : dam if it'd been a few months earlier he could have had my sony subwoofer for free as it was to big (was given away to a charity shop i think) http://www.phpbbserver.com/mameuifx/images/smiles/a_doh.gif



My buddy has his mixer and pevy amps with subs hooked up to his pc in and out f#$king awesome wish I had that setup 18 channles unreal sound out of an old p4 with 512 ram


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## Steevo (Aug 20, 2009)

The last one I built was to fit two 5.25" basic speakers in it, and run off line power through a crossover. It was actualy really loud, and the box filtered out more, plus it provided clean punch. It would fit under the seat in a friends pickup, once he traded it off, i took it and hooked it up to my amp, and ran it four a week before I melted the voice coils and set the cones on fire.


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## Wile E (Aug 20, 2009)

KH0UJ said:


> I guess we have both extensive experiences about sound system set-ups
> maybe im wrong but i cannot find an 8 OHM speaker for sub to respond the 10 HZ-43 HZ last time no matter how i tuned the ported box, that`s why im just gonna utilize the owner`s current set-up than buying an expensive DVC 4 OHM speaker (2 ohms paralleled) and rewind it to a single 2 OHM speakers, maybe it depends on what`s our sub-woofer target frequency design, cause im basing it on my custom active 4rth order low-pass filter circuit (custom cross over) which is 10 HZ to 43 HZ and i find the 2 OHMS speaker has a great response on my DB meter



Did you compare the 8 ohm models against the identical 4 ohm (or 2ohm, as the case may be) models? The 8ohm model is tuned to run at 8ohms, and sound the same as the 4 ohm models, when looking at the same model of sub. Although, true 8 Ohm subs are a rare bread nowadays. You usually can only find 4ohm DVC models anymore, short of going special order.

I never got so far as to rewinding my own coils. I bet rewinding has a huge impact on sonic output. Something I would like to try at some point. I'm sure I can scrape up something for dirt cheap with smashed coils, and give it a go someday. 

I just have a good ear for SQ, and happen to understand how to set up a system, so got recruited for SPL stuff as well. I also ran live sound for bands, and have helped record, produce, mix and master albums.


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## KH0UJ (Aug 20, 2009)

Wile E said:


> Did you compare the 8 ohm models against the identical 4 ohm (or 2ohm, as the case may be) models? The 8ohm model is tuned to run at 8ohms, and sound the same as the 4 ohm models, when looking at the same model of sub. Although, true 8 Ohm subs are a rare bread nowadays. You usually can only find 4ohm DVC models anymore, short of going special order.
> 
> I never got so far as to rewinding my own coils. I bet rewinding has a huge impact on sonic output. Something I would like to try at some point. I'm sure I can scrape up something for dirt cheap with smashed coils, and give it a go someday.
> 
> I just have a good ear for SQ, and happen to understand how to set up a system, so got recruited for SPL stuff as well. I also ran live sound for bands, and have helped record, produce, mix and master albums.




ya bro i was comparing them by their intensities on the low frequency sounds (10HZ to 43HZ), some of my clients last time entered 

sound off competitions, me as an installer on their set-ups I need to be there also in the event, the first month we lost only by 

two votes so im observing the judges the way they judge on the intensities cause i know our set-up have a lot more power than the 

winner on that event, ours have 6 pcs. 12" inch DVC (4ohm+4ohm) 6 pcs. 1000W double inverters on each amp. plus the mids and the 

high stuffs, my client entered the crawling bass category, so after the terrible loss i kept thinking of the situation why and how 

did we got beaten by only 4 pcs. 12" subs:shadedshu, the owner was so pissed (epeen thing) by the judges, for me as his installer i am 

humiliated too on that event cause im the one who plannned, tuned and made the whole set-up on his expense, the next day i decided to redesign everything (fueled by rage) I converted and rewinded each and every speaker to 

a (2ohm+2ohm) load to maximize everything, installed a second 200 ampere alternator, one amp has 2 channels on one speaker DVC (2+2) 

last time its (4+4) on one amp, replaced the crappy 1 FARAD powercaps with a 100 ampere audio battery, one week of box tuning and testing, on the 

next month we entered again, damn im nervous on the results same category and same everything, thank god we finally won and dust 

off the one who beat us in the past competition, seems like the judges are measuring thier DB meters on the low frequency range, 

cause the moment I lowered the resistances and tune it on a lower frequencies on everything we have higher passmark score on the 

judges, and one thing i hate about that competition, the judges use thier own testing CD bro, so meaning we cannot use our edited 

music (bass enhanced) to ride on our sub set-up (clever freaks:shadedshu)  

So i finally concluded (just my opinion basing on my experience) that the lower the impedance the better response on the lower frequencies, the higher impedance the better 

response on the higher frequencies.


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## KH0UJ (Aug 21, 2009)

This is the block diagram as far as i can remember before I never took a chance to take pictures on my builds before cause im too poor to buy my own camera last time i can only visualize it on my mind but no proof that im the one building it, and besides its not mine also along with the trophy, the only thing they cant take from me is the knowledge and the planning that added greatly on my experience.


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## Wile E (Aug 21, 2009)

KH0UJ said:


> This is the block diagram as far as i can remember before I never took a chance to take pictures on my builds before cause im too poor to buy my own camera last time i can only visualize it on my mind but no proof that im the one building it, and besides its not mine also along with the trophy, the only thing they cant take from me is the knowledge and the planning that added greatly on my experience.
> 
> 
> 
> http://img.techpowerup.org/090820/Stereo Set-up.jpg



That's a nice looking setup. What kind of vehicle did you stuff this all in?


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## KH0UJ (Aug 21, 2009)

Wile E said:


> That's a nice looking setup. What kind of vehicle did you stuff this all in?



its a Honda civic 98 sir the two door edition, no more back seat, it looks like this




actually i just grabbed that picture on google and its a blue color, the most PITA to install on that one is the second alternator i had to take out the main engine pulley and bring it to the machine shop to install the modified pulley just for the additional alternator a rock solid 3 day job just for adding the custom mountings and belt adjusters


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## Taz100420 (Aug 21, 2009)

For your question as to the Front or downfiring cab Selway, it really depends on what type of flooring u have. If you have carpet, use a front firing cab as the carpet dont let the sound reverberate anywhere. If you have wood floors, def. downward firing cab as the bass will sound good as it reverberates alot better.

For my home sub setup, I use a JVC 10" sub in a front firing cab with a 240W Coustic amp(from my car) with a 400 Watt PSU from my old computer. It sounds real good as I have the gain all the way down as its way too loud in my house lol.


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## selway89 (Aug 22, 2009)

Ok peeps Iv built the sub  sounds brilliant just what I wanted. However I only have it running from the left channel so any bass on the right isnt getting through. 

I were thinking of getting this http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=230366877344&fromMakeTrack=true#ht_500wt_1182 which will take high or line inputs with built in crossover and will power a mono sub from that fine. However im not sure how i would power it.... use old PC psu?

pics shortly

edit: bought that amp it were around a tenner so cant be bad if its not right. It has the option to bridge it so worth ago.


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## KH0UJ (Aug 23, 2009)

selway89 said:


> Ok peeps Iv built the sub  sounds brilliant just what I wanted. However I only have it running from the left channel so any bass on the right isnt getting through.
> 
> I were thinking of getting this http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=230366877344&fromMakeTrack=true#ht_500wt_1182 which will take high or line inputs with built in crossover and will power a mono sub from that fine. However im not sure how i would power it.... use old PC psu?
> 
> ...



That amp. is a nice one bro specially the price £4.00, use the low inputs on it, soundcard output is so weak to trigger the high input, use a stereo mini plug with a 2 RCA plugs at the end and set the soundcard volume to full volume then trim the output on the amp`s potentiometer, dang bro it even has a third stage low pass filter on it


and for the PSU, you can use an old 450W PC PSU make a switch on the green and black wires (7-10A current consumption on the 12 volts I think), 


KAC-626 Stereo / Mono Power Amplifier 
Bridgeable 2 or 1 channel output 
Max. power out-put (4Q) 2ch: 100W x 2, 1ch: 300W 
RMS power (4Q) 2ch: 50W x (20-20kHz, 0.08% THD); 1ch: 
150W x l (l kHz, 0.8% THD) 
2Q load capability (0.8% THD): 75W x 2 
Tri-Mode Operation 
Preout high/low pass filter (80Hz) 
3-way input mode selector (stereo / mono / L+R) 
DC-DC converter power supply <<<This is the split type power supply im talking about +12Volts is being stepped up to +26-gnd-26 (positive-ground-negative)so if you measure the +&- side of it it will result                                   to +52 volts DC (stepped-up DC)

Gold plated terminals                           

Speaker level input                       

this are the specs. 

make sure to use the 2 inputs when you bridge the output, otherwise it will not work (some amps will sound distorted, and some amps will have very low output sound)


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## selway89 (Aug 23, 2009)

Yeah I know I'll be taking the headphone out from the Cyrus into the phono rca in, this means when I adjust volume on the cyrus and mission speakers the sub changes with it. Or I could wire the high output from the cyrus into the high level input on that.

So ill put it into the bridge mode where the signal gets mixed and then put the sub across one of the speaker outputs.


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## KH0UJ (Aug 23, 2009)

is your cyrus amp have just a plain stereo RCA output? how about connecting it to the plain output (if it has) to slave your secondary sub woofer amp.?


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## selway89 (Aug 23, 2009)

I does labelled tape out but the volume doesnt change on that as its for recording. Thats why I think that amp is good with its high level in. The TEAC is currently fed from the headphone out on cyrus fine and works perfectly minus the right channel. Noticed that you can hear a fair bit of noise from the teac as it has to work at higher volume. Cant wait to have a play with that amp


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## KH0UJ (Aug 23, 2009)

I enjoyed Drawing LOL


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## selway89 (Aug 23, 2009)

Yeah thats how it looks, using the headphone out like iv said controls the volume in sync with speaker volume.


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## KH0UJ (Aug 23, 2009)

try to eliminate amp series connection, it increases distortion levels, or maybe try the headphone output, the problem of it is, the moment you plug the headphone plugs, it mutes the main amp. what i did on mine is, ived directed the internal switch inside the headphone jack itself, (there`s a tiny switch inside of it that mutes the main amp. everytime a plug is inserted) in that way i can still use the master volume control of my mini component and utilizing also the main power amp. with the built in speakers on my mini component.


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## selway89 (Aug 23, 2009)

Well thats the beauty about the cyrus amp, having the headphones plugged in doesnt mute the speakers


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## KH0UJ (Aug 23, 2009)

selway89 said:


> Well thats the beauty about the cyrus amp, having the headphones plugged in doesnt mute the speakers



Well you`re done man, that`s it 

7 more post to the 5 star LOL


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## selway89 (Aug 23, 2009)

Here are some pics, its not fully sanded down or painted yet. 


















The box is still around 30 litres but different shape, luckily it was pre-made from a desk I made in school few years back and the box sections for the draws is 30 litres, so cut the holes required and screw and glued it together with carpet underlay and some foam padding from an old arm chair.


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## Deleted member 24505 (Aug 23, 2009)

Nice M71 speakers  do they sound niice.


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## selway89 (Aug 23, 2009)

Yeah they're brilliant little things and with the sub have abit more meat to the sound, they are actually M30i


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## Wile E (Aug 24, 2009)

Take the speaker down from there, and place it firing directly into the corner of the walls, about 1ft back.


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## selway89 (Aug 24, 2009)

Yeh I know I had it up there to see what difference there was from carpet to something solid. Got it under the desk at the moment.


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## selway89 (Aug 26, 2009)

Well my new amp has arrived, and it sounds fantastic, and very powerful , its all painted up now so here are some pics:


























The power supply is an old Seasonic with a physical power switch, I opened it up and un-soldered all the other rails so there are no wires hanging around.


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## pantherx12 (Aug 26, 2009)

Nice job man!

I've been looking for tutorials EVERYWHERE to turn computer PSU into amp PSUs.

I don't suppose you'd be willing to help me out? 

PSU's are easy to come by and it means I can get a amp with high w rather then an indoor amp with less power.


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## selway89 (Aug 26, 2009)

pantherx12 said:


> Nice job man!
> 
> I've been looking for tutorials EVERYWHERE to turn computer PSU into amp PSUs.
> 
> ...



Sure of course. It's fairly easy to get a PC PSU powering a car amp. It's best to know what power draw (Amps) the amplifier will take.
I used a regulated power supply with voltage control and Amp gauge and saw the amplifier drew less than 2A at the volume I normally use, so make sure the PSU you choose has the required Amp rating on the 12V rail. 

Also check the voltage on the 12V rail is in the operating range for the amplifier.... First PSU I tried had around 10V on the 12V line which was terrible and the amp didn't power up.

Next bit is simple case of gathering up a couple of 12V and Ground cables (yellow and black) and pairing them together in parallel.

For an ATX PSU to start it you need to short the green and black wires on the ATX 20-24pin header, or if it's an old one like mine just power it up.

Edit: Also allot of car amplifiers have ignition sense terminals. I just put a jumper from the 12V to the sense terminal so it turns on straight away.
Edit2: It might be wise changing the fuse on the amplifier to the rated Amps on the 12V on the PSU or have it slightly less. This will protect the amplifier and your PSU and blow the fuse first, not the equipment. (Iv yet to do this so not going to run it at full tilt yet  )


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## Taz100420 (Aug 28, 2009)

Yea a amp from a car dont need to be a high wattage, trust me. I have a 50W Rockford on my 10" sub and it blasts me outta my chair. I changed it to put my amp back in my car lol, way too powerful for this and its a 240W!!


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## selway89 (Aug 28, 2009)

Yeah after having it running for a little while now I have come to the conclusion that some songs etc are abit too loud. So I've bought an attenuator for earphones for when on the plane, this will hopefully allow me more control over the sub amp as I currently cant turn it any lower. I dont need to do it by much but its enough to get on my nerves in some cases.

Overall though I'm ver happy with it


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## KH0UJ (Aug 28, 2009)

you did not bridge the tapping on the out bro? I think it only output the left channel on your pics
I think the bridge tapping on that is on the two outer sides of the amp. speaker connector


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## selway89 (Aug 28, 2009)

Nah there's no need. I have it on the mode where Left and Right are mixed then amplified so it doesn't make any difference. I adjusted the balance on my sound card to left and right and it comes through fine.  the attenuator didn't work as planned so sending that back next week.


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## KH0UJ (Aug 28, 2009)

on mine i hide my amp supply inside my box I like hard modding though, its only a 10 amp.transformer, I bolted it inside, mine`s also a 12V car sub but I hard mod it to have a 110VAC supply like this,






figure 2 is a typical DC-to-DC split supply system on a car amp.

I really love drawing circuits on paint


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## selway89 (Aug 28, 2009)

I would have built it in but its quicker this way as I have a job coming up so needed to get it out the way, also buying the components to do it would be an extra cost so just thought i'd do it the free way.

Also the amp has different modes.... Standard stereo, mono (bridged over L+ and R- terminals, which only uses the Left channel) and mixed where left and right are mixed then amplified for both Left and Right mono.... so I could have another sub wired up hehe


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## KH0UJ (Aug 28, 2009)

BTW nice build man


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## KH0UJ (Aug 28, 2009)

selway89 said:


> I would have built it in but its quicker this way as I have a job coming up so needed to get it out the way, also buying the components to do it would be an extra cost so just thought i'd do it the free way.
> 
> Also the amp has different modes.... Standard stereo, mono (bridged over L+ and R- terminals, which only uses the Left channel) and mixed where left and right are mixed then amplified for both Left and Right mono.... so I could have another sub wired up hehe



another sub FTW


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## KH0UJ (Aug 28, 2009)

There`s a saying way back on my modding days bro

"IF THE MUSIC IS TOO LOUD THEN YOU`RE TOO OLD"

 crazy client he actually put it in his wind shield bro
while roaming around with his car intimidating every granny in town with a full blast crawling bass and triggering all the nearby parked alarmed cars in the parking area, I think that guy is nuts.


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