Wireless Performance

As mentioned earlier in the review, the Sennheiser GSP 670 offers dual wireless connectivity. It comes with a wireless USB dongle that uses the standard 2.4 GHz radio to wirelessly communicate with the headset, which you'll use when connecting the headset to your PC or PlayStation 4. Bluetooth 5.0 connectivity kicks in when you connect it to a smartphone or some other mobile device. The GSP 670 can remember up to eight different Bluetooth devices, but can only be wirelessly connected to two devices at once—one via Bluetooth and another through the 2.4 GHz radio connection. The 2.4 GHz radio is prioritized, meaning should you send any audio from your PC or console, the Bluetooth connection will instantly be interrupted, and you'll hear the sound that is coming from the wireless dongle.

The only case when the Bluetooth connection will take control of the headset over 2.4 GHz radio is when you have an incoming phone call. When that happens, the game audio stops and the headset switches to your phone call. You can, of course, use the headset's microphone to talk with the caller. Once the call is done, the headset will automatically switch back to game audio.

The overall wireless performance of the headset is flawless. There are no interruptions, drops, or delays with either 2.4 GHz radio or Bluetooth. There was a bug in an earlier version of the firmware that caused an annoying microphone delay in voice apps such as Discord and TeamSpeak, but I'm happy to report that the issue has been fixed completely. Existing and future owners of the GSP 670 won't experience it if they use the Sennheiser Gaming Suite to update the firmware.

Battery Life

Battery life is highly dependent on the way you use the Sennheiser GSP 670, and not only in terms of listening volume. The Bluetooth connection is easier on the battery; at a moderate volume level, you can get up to 20 hours of battery life when using Bluetooth. The 2.4 GHz radio connection cuts that down by around 5 or 6 hours, so you'll have to recharge the headset after about 14 or 15 hours of use. Blasting it very loudly cuts battery life by another couple of hours. The headset's battery charges quickly—a mere 7 minutes of charging will provide you with another 2 hours.

You can, of course, charge and use it at the same time. You won't need to use the wireless dongle while the headset is charging, though. As soon as you connect it to your PC via USB, it transforms into a wired USB headset. While nice, this can lead to some confusion. Should you leave the wireless dongle connected, which will be the case for most users, your PC will recognize the headset as two devices. Given your PC already sees it as two playback devices, you'll have a grand total of four devices listed in the Sound > Playback section of the Control Panel: the Sennheiser GSA 70 Main Audio and GSA 70 Communication Audio from the wireless dongle (GSA 70 is the name of the dongle) and the Sennheiser GSP 670 Main Audio and GSA 670 Communication Audio from the USB connection. With that in mind, it's perhaps best to use a phone charger to recharge the battery, which keeps things as simple as possible and avoids fiddling with Discord/TeamSpeak settings.

The Sennheiser GSP 670 also offers a function Sennheiser calls Intelligent Battery Management. In essence, it automatically turns the headset on as soon as sound from your PC/PS4 is played and sends it to sleep after the SP 670 hasn't received any audio for 10 seconds. Should you want to control its on and off states manually, rotate the volume wheel as if to mute the sound. At its final position, the headset turns off (and turns back on once you start increasing the volume by using the wheel).