2B Stereo - Audio Mirroring and Music

[verispalles]

Experimenting with the Stereo mode of my 2B and wanted to share some tips in case anyone else uses Linux to drive their 2B. My setup uses a Linux handheld to drive audio output to multiple devices, allowing listening at the same time as the box reacts to the music.

Audio Mirroring

Helvum (https://github.com/relulz/helvum) allows you to connect audio devices together. In Helvum, With a Bluetooth headset as the selected system audio device, connecting the monitor nodes from that output to the input nodes of the audio jack will mirror the audio output with virtually no added latency.

In the image below, I'm using the device speakers to listen to the music and have connected the speaker to the headphone jack.

https://pixeldrain.com/u/CT5tgu8v

I've accomplished the same thing on Windows in earlier projects using VB-Audio (commercial), Virtual Audio Cable (commercial) and Audio Router (open source) so I'm sure there are ways on Windows. Some sound cards may also have this feature built-in.

Stereo Mode Volume

I have seen some estim experts referring to the importance of volume levels and in my testing its very important for stereo mode. I don't know whether its just my sound drivers but I was often finding channel B would move lots, while channel A was completely quiet despite sound playing (at 70% device volume). Bumping device sound level up (to 95 - 100%) was necessary to bring both channels to music responses I would expect. Instead of maxing out channel B, increasing the volume actually lowered the responses on the device to a level that made sense with the music. Be sure to test a range of volumes to see what works best for your music. My recent testing has been on EDM and trance so your experience may vary.

For reference, if anyone is using similar hardware, my volumes are usually 100% in software (e.g. VLC), 90 - 100% in hardware (system speaker volume) and 50 - 70 adjust on the 2B stereo mode.
Device: 2B
Software: Version 2.106
Hardware: Steam Deck

Stereo Mode

I highly recommend checking out your favourite albums or videos using a similar setup. PMVs are also fantastic, with some of the CH videos providing an underlying heavy beat that you can really feel through the 2B. PMVHaven has been very fun to explore with a well-calibrated stereo setup. Electric Dreams by Rillo on Milovana is also worth a look - with the option of using the intended estim frequencies or the music in the video itself.

While classical music is not everyone's taste, there are some interesting trends that lend themselves well to working with stereo mode. Orchestral positioning is quite consistent, with different instruments (and therefore sounds) maintaining similar positions across recordings and compositions. Woodwind instruments, often centrally located and quiet in their solo sections will result in short breaks in signals. Viola or cello sections will often find themselves dominating the right channel with heavy percussion and low brass. I have no idea where the cannons were located in the final four minutes of Tchaikovsky's 1812 overture but it doesn't matter, you can certainly feel them.

A note to the developers: fantastic work! Stereo mode is incredibly well tuned. The audio files used in most files and experiences are very well crafted, but having a stereo mode that can react to existing music well opens up a lot of possibilities.

I've seen some posts on different firmware having different stereo modes so I'm looking forward to exploring those next. Also hoping to come up with a customisable solution to play a video with two synchronous audio sources to different devices. Happy to help troubleshoot if anyone has issues or ideas, DMs are open.

Please share any stereo setups or experiences that you really enjoyed!