DMAS Design [SPDIF-Optical]

[Ferather]

GaN Systems Extends its Lead in Class D Audio | GaN HEMTs Outperform MOSFETs | Amazon Search: GaN USB Charger.
An upgrade for optical pulses, and PowerDAC's, both apply to the DMAS sound system.

Note: The total THD, THD+N for the main DMAS audio output should be extremely low (SoC mostly).
Conversion to power (main THD point) is done by each speaker (PowerDAC).

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[Ferather]

Here is a SFX digital filter (I got the idea from ferrite beads), it attenuates frequencies beyond the set value, which is set to 22kHz. Human hearing range is 20Hz-20kHz so 22kHz is above.
Digital sample rate divided by two, equals the maximum frequency it can represent (without aliasing), 44.1 = 22.5kHz, 48 = 24kHz audio frequency.

In an ADC situation (analogue to digital), if a DMAS was to support analogue, an analogue filter would do a similar job.
Oversampling allows the higher frequencies to be captured, then removed (down sampled).


Technically speaking, in 32 bit float terms, the attenuation should amount to 'silent aliasing' if any occurred.

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[Ferather]

Interesting SPDIF item: https://www.matrix-digi.com/product/20/X-SPDIF_2 | Not a DMAS but similar in the basic sense.

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My RTN method uses nil start-stop (off state) and packets, it does have a clock, however its a bit clock.

 

[Ferather]

Here is something else similar to my DMAS design, except the DMAS speakers have their own individual P-DAC, it does focus on lossless audio and bitperfect audio data.
Personally I feel the unit is potentially over priced, considering it doesn't seem to do multichannel. It can be updated via firmware updates.

It uses TOSLink and advertises < 0.001% THD (lower than, distortion), 2 Ohms balanced (see the specs sheet).

https://ecdesigns.nl/product/powerdac-sx/

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Not as flexible as the DMAS, as the programmable SFX, MFX and EFX processing points can be used in various ways, including SFX lookahead and MFX or EFX application.
AVR these days also use 32 bit (not float unfortunately) digital processing, but then a 24 bit DAC, in better cases a 32 bit DAC, but still an amp.

The DMAS (Digitally Managed Audio System) is fully digital right up to, into, the speaker, which is essentially a digital speaker.

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DMAS note, since there is no DAC or analogue amp, the number of channels is limited by input, processing, power supply + physical combo modules (per speaker).


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Reiteration of [Digital] Class-D, which is what a P-DAC essentially is:



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Expensive headphones plugged into random DAC's will produce random quality, built in converter will produce constant quality.

What is True Sound? The concept explained | Stuff

Your guide to the philosophy behind ear-pleasingly accurate audio - True Sound

www.stuff.tv

 

[Ferather]

Looks like Linsoul have ownership to the E1DA PowerDAC, its also sold as Linsoul E1DA PowerDAC on Amazon, although I only found v2 (out of stock).

 

[Ferather]

MSC8256FS.pdf (nxp.com) | TMS320C6678ACYP4 Texas Instruments

 

[Ferather]

TMS320C6678ACYP Texas Instruments (more specs to see, slightly cheaper).

 

[Ferather]

Please note that the connection between the DMAS main unit and DMAS speaker is optical, an optical core with 2-3 additional copper wires for power (PCM-optical, power-copper).
In addition none of my designs or ideas are copyrighted so feel free to use them, its an open design. Might as well call the cable a DMAS cable.

Also note that SPDIF is only as good as the hardware either side of it, and whatever the current IEC standards are.

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Also, if the intention is 2 channel output (stereo), then it should work out better to accept 15+ channels (PCM), then process each channel for spatial output via stereo.