Multiple Inputs

[dpickett]

Hi,

I love Audacity but as I move into bigger stuff I have hit a snag. I currently record solely with one USB Microphone which all works fine, however, I wish to buy a MIDI to USB adaptor for my Keyboard so I can record Vocals through the USB Mic and the accompaniment through the MIDI to USB connector. This will allow me to listen through headphones to the Keyboard and output it to the PC without making any Keyboard and have the Vocals recorded solo with perfect accompaniment.

But, how do I set Audacity up so that I have two inputs which would be both USB and then record them at the same time? If Audacity can't do this please point me to a free program that can with a tutorial.

[steve]

I wish to buy a MIDI to USB adaptor for my Keyboard so I can record Vocals through the USB Mic and the accompaniment through the MIDI to USB connector.

MIDI is not audio. MIDI signals are just control data that allows devices to communicate with each other. You would "record" MIDI data in a Midi Sequencer and use it to control a synth or sound module which may either be a hardware or software device. The synth/sound module would then generate the audio which you can then record.

Audacity is an audio program and does not support MIDI.

I don't know of any good free programs on Windows for audio and Midi, but Reaper is low priced and has a demo version and Cakewalk make some inexpensive versions that support both MIDI and audio.

[dpickett]

OK! That's really useful thanks! I may just use a Mixer and plug in my Keyboard and Vocal Mic. Still my question applies, if, I kept my USB Mic and used a JACK to USB adaptor how could I record both USBs at once?

[steve]

No. Audacity can only record from one device at a time.
I think that Wavosaur may be able to record from more than one device at a time.

[dpickett]

Thanks! I may therefore invest in a mixer so I can just record from that source! Thanks.

[george13]

Is there something like an "aggregate device" on Windows?

On a Mac you can set up an aggregate (virtual) device with multiple inputs made out of several physical devices. I've used Audacity to record 4 channels (two channels from a firewire audio interface and two built-in audio).

I wonder if something similar isn't possible with Windows or Linux?

[kozikowski]

<<<On a Mac you can set up an aggregate (virtual) device with multiple inputs made out of several physical devices. I've used Audacity to record 4 channels (two channels from a firewire audio interface and two built-in audio).>>>

And how did you do that?

Koz

[george13]

And how did you do that?

I actually regretted posting this (on the windows forum, in the role of the smug mac user ). But here's how:

In the 'audio midi setup' there's an 'aggregate device editor'. i ticked 'resample' for both, but hopefully, when all are set to the same rate, there's no need to resample.

In Audacity, the new aggregate device turns up as a third input source with 1,2,3, or 4 channels.

aggregatedevice.png (66.31 KiB) Viewed 1856 times

[dpickett]

Can this be done on Windows at all? It would save me buying a mixer, XLR mic and cables!

[steve]

It can be done on Linux using the ALSA pcm_multi plugin, though doing so requires a bit of hacking, so is not straightforward. There has not been much interest in developing a graphical application for this because of the inherent hardware limitations involved (see below), but there is some information on the subject here: http://alsa.opensrc.org/index.php/TwoCardsAsOne

I'm not sure if it can be done at all on Windows. Perhaps with VAC ? http://software.muzychenko.net/eng/vac.html
There is a free trial version of VAC (Virtual Audio Cable) if anyone has the hardware set-up to test this.

Hardware Limitations:
A major limitation of these solutions is that there is no synchronisation between the sound cards, so the recordings from each sound card will gradually drift out of time from the other sound card(s). It may be close enough for short recordings of a couple of minutes or less, but likely to be a problem on longer recordings. To fix this would require removing the timing crystal from all but one sound card and hard wiring the one remaining crystal to the other sound cards. This will invalidate any warranty.