Recording two separate inputs over one mic input.

Hi, I am using WAVRECORD to capture an analogue voltage so I can study the frequency components present. I have two different devices which are each producing a waveform. Both waveforms are mono. WAVRECORD gives the option to record in stereo, when this is done the two channels are summed (I assume internally by matlab). Is it possible to send different data over the two channels and output each channel separately? example [left,right] = WAVRECORD(..,..,2)? alternatively is there another way of doing it? Matlab says to many output arguments. In short, I want the data from both channels, before being summed. Thanks in advance Tim

Answer 1

[Daniel Shub]

You probably want to use audiorecorder instead of wavrecord. You can only return 1 argument, but it can be nx2 such that x(:,1) is the left and x(:,2) is the right channel.

You should be able to record in stereo. I doubt it is MATLAB that is screwing things up. You should try an external audio recording program and see what happens. It is likely that your soundcard is setup for a differential microphone.

[Tim Mottram]

Hi Daniel,

Thanks a lot for your speedy response, You were quite right, although I can still use WAVRECORD, the matrix is, with two channels, (NumOfSamps,2). I can now use (:,1) and (:,2) to generate the freq values for my two plots.

My Greatest Thanks

Tim

[Tim Mottram]

Hi Daniel, Thanks for your response last time, it seems that I am still not in the clear, i have a 2 by samp number array but i think your point about the mic input being in differential mode is whats screwing things up. Both plots (supposedly from 2 different sources) are the same, any ideas on how to change from differential to 2 single ended, is this is even possible..?

Thanks

Tim