ACCESSIBLE PEAK METER FOR TWO SOUND CARDS
Sometimes visually impaired musicians and audio producers might want to hear the audio content they are working on - such as a recorded track - and the audio that helps them accessing their system - like the voice of screen readers - from two separate sources. The computer speakers for the former and a pair of headphones for the latter would be a plausible configuration. Separating prevents the two audio streams from cluttering each other.
Screen readers access the content of the computer's interface at the operating system level. Single applications don't have control on which channel the screen readers output their chatter. You can't therefore just use your DAW's routing capabilities to make the separation. The way to do this is, instead, to use two separate sound cards: one for the audio content and one for the screen reader.
We wanted to offer the same kind of set up for the sonification of the AccessiblePeakMeter, but the VST/AU format doesn't lend himself to a separation of audio streams, so we came up with a "hack" of the AccessiblePeakMeter that does the magic.
AccessiblePeakMeter2S ( 2S stands for two soundcards ) is a special version of the AccessiblePeakmeter: you would drop into your DAW's track like the standard version, but instead of outputting the sonification in the same track, it will send it straight to your system's default sound card. The audio content that you're sonifying will still be sent to the DAW's track, as usual.
A possible set up to have the two audio streams on two different sound cards would then be the following: set the sound card for sonification as default system card, and tell your DAW to use the second (probably more expensive and performant) sound card for your audio content. That's it !
Of course nothing comes for free though. There are some catches to deal with:
- First of all the 2S is a hack: it pushes a bit the way how a normal plug-in is expected to work. Although we tested it in our systems, your DAW might not like how it allocates and deallocates computer resources and could give you an error. Please let us know if that happens to you;
- At least for the moment, 2S is available only as VST for Windows 32-bit and 64-bit;
- You can use only one instance of 2S per DAW at the time. Feel free to move it across your tracks or to delete it and recreate it at will, but if you pull off two or more instances together, they'll start conflicting with each other and produce inconsistent and not useful at all sound;
- In order to work around latency, 2S uses WASAPI audio driver with a buffer size of 64 samples. This is likely to make the sonification sine wave a bit distorted (but still useful!). Also if you allow for a large audio buffer in your DAW, you might get your audio content and the sonification out of sync, cause the latter is independent from your DAW settings and it's fixed at 64 samples buffer size.