Harp Soundcard stop message writes to device, but does not stop sound

[rachelmcassidy]

I am cross-posting this question I asked in the bonsai-rx discussions because I still can't use my sound card until I'm able to control when sounds stop. I've since tried resetting the device, reinstalling the drivers and firmware, and checking that the stop payload register is still saved in the device metadata. I've also tried creating an "EnableEvents" message for stop events. Nothing has fixed it yet. Thanks for any help you can provide!

Hello,

I would like to play sounds with the Harp soundcard and stop the sound based on different behavioral events. I've started with a simplified workflow, where different key presses start and stop stored sounds. The sounds play, but neither of the "stop" branches I've tried works. The write command is displayed in the device events, but there is never a corresponding event logged.

Am I using the CreateMessage node with StopPayload correctly? Does the "Stop" value in the node properties matter?

Thanks for any advice!

Device Initialization:

> > KeyDown triggers trying both **CreateMessage** and **Format** operators:

> > Output of **Soundcard Events** visualizer during key presses:

> > [soundcard_demo.zip](https://github.com/user-attachments/files/21550780/soundcard_demo.zip)

[glopesdev]

@rachelmcassidy there is currently no direct support to "stop" pre-uploaded sounds. (The "stop" register only works for dynamically generated frequencies.)

Usually we workaround this limitation by simply playing a "silence" waveform.

[rachelmcassidy]

Thank you for the suggestion! I have a few follow-up questions to understand how overlapping play events would work.

• I have pre-uploaded sounds that are 5 seconds long. Does sending another play command cancel the original one or would the original sound resume if the silence waveform was shorter?

• If I wanted to play a sound (white noise) continuously beyond the stored 5 second waveform, could I send another play command that waits for the first waveform to complete? Do you think overlapping/sequential sounds would be continuous or would there be a click in between the buffers?

• Are there any timing restrictions on how close together multiple play commands can be sent?

• I plan to use this sound card with the harp audio switch, but haven't set that up yet. Would you recommend using the digital input to the switch to stop ongoing sounds instead?