Recording second track does not work using USB for recorder and playback

On the toolbar of audacity 2.3.1 I set the “recorder” and “playback” on the same USB interface.
Recording the first track, all works well.
Start Recording the second track and the ruler bar come red, but stays on the same left position and no recording took place.

When I change the “playback” to the internal speaker of the laptop all works fine.

Is this a known bug?

Friendly greetings

USB interface.

What’s the USB interface?



It’s a Tascam us-366 digital mixer

Luc DC

Has playback to the Tascam ever worked? It is stressed that Record and Playback work perfectly by themselves before you try overdubbing. There are too many interactions to stop an overdub session in the middle and try to figure out what’s wrong.

I’m sure the Tascam claims astronomically high technical specifications, but try setting up Sampling, Bit Depth and Stereo at 44100, 16-bit, Stereo. Those are plain, ordinary specifications and everybody supports them.

Is this a known bug?

I wouldn’t open a conversation with technical support by using the “B” word.

That’s like asking if we’re insanely incompetent or if our parents ever did get married. Not a good start.


Ok, forget the B word, sorry.
A better question could be: Is overdubbing a supported feature using the same USB interface for recording and playback?
I’m aware that the interface of Tascam could be the cause of the error.

Anyhow, thanks for supporting me. I did some test as you mentioned but with the same result.
Still, when I do the same test using the WASAPI audio host, Audacity crashes. I attached a screenshot and log files.

Luc (87.7 KB)

The three examples of successful overdubbing were done with USB sound devices. One UCA-202

One G-Track microphone,

…and one X2U microphone interface.

So yes. I expect that to work. The earbuds are there because they were pretty, they work and I had them. I wouldn’t mix a symphony on them.

I need to look at the mixer specs. I can’t believe a manufacturer would offer a USB mixer without the possibility of hearing the playback through the mixer headphones.


The mixer might sorta do what you want. I see two references to transfering sound from the computer by optical, not USB.

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Screen Shot 2019-04-18 at 10.12.39.png
So that’s why the USB Send fails.


Thx for the effort.

I don’t understand the conclusion “… so that’s why the usb send fail…”

When I play one track on the playback interface it works and the connected speaker on the tascam produce sound. The signal is coming from the usb port on the computer.
Only during overdubbing it blocks.

Anyhow, does it mean that this Tascam us-366 is not able to use the overdubbing function or do I have to change something?


The signal is coming from the usb port on the computer.

That’s the puzzled look. According to two different places in the instructions, sound enters the Tascam via the optical digital connections. No mention of the USB.

The controls on top don’t say “USB Return” or “Computer USB” like other mixers. They just say “Computer.”

Screen Shot 2019-04-18 at 12.45.28.png
There is another danger sign. There’s this on the Overview page.

Screen Shot 2019-04-18 at 12.48.04.png
You may be experiencing the reason it’s discontinued. Maybe someone else will post. I’m out.


Ok, thanks!