David Christensen <dpchr...@holgerdanske.com> writes: > On 07/28/17 12:11, Rodolfo Medina wrote: >> According to: >> >> http://www.upubuntu.com/2013/05/how-to-record-your-voice-from.html >> >> I record live sound via microphone just doing: >> >> $ sox -t alsa default output.wav >> >> Now I was wondering about the stereo o non-stereo character of such a home >> made recording... I tried to use two microphones together, plugging them >> together into the PC with a small common connection doubber. Can we say the >> result is stereo...? I would doubt... and how to have - if possible - a >> stereo effect with the above basic recording instruments? > > Connecting two monophonic microphones in parallel with a connection splitter > run backwards will yield a monophonic signal with reduced gain and time/ > frequency signal artifacts such as comb filtering and echo. For most > applications, the result will not be acceptable. > > > Capturing sound with two microphones can be done several ways: > > https://en.wikipedia.org/wiki/Stereophonic_sound#Recording_methods > > > Computer microphone port(s) are typically monophonic and the line input > port(s) are typically stereophonic. If you want to record in stereo, you > need to provide left and right channel signals to the line input port. > > > Computer microphone ports and line input ports also expect different voltages > and have different impedance. I believe computer line input ports are > designed to consumer audio equipment standards -- e.g. -10 dBV into 10 kOhm > for 0 VU: > > https://en.wikipedia.org/wiki/Line_level#Nominal_levels > > > (For microphone ports, my guess would be -30 dBV into 1 MOhm.) > > > This means you need two microphone pre-amplifiers and/or a stereo mixer with > two or more microphone inputs: > > https://en.wikipedia.org/wiki/Line_level#Line_level_in_traditional_signal_paths > > > The audio capabilities of Linux have evolved over the years: > > https://en.wikipedia.org/wiki/Open_Sound_System > > https://en.wikipedia.org/wiki/Advanced_Linux_Sound_Architecture > > > Sox is a command-line tool that has been around since 1991: > > https://en.wikipedia.org/wiki/SoX > > > Audacity is my favorite interactive audio recording and editing tool: > > https://en.wikipedia.org/wiki/Audacity_(audio_editor) > > > If you would care to explain your application, we might be able to give more > advice.
Thanks all of you who kindly provided response. What I want to do is recording live piano: I'd like to use two mics for that, one on the grave and the other one on the high notes. Besides, some times I will need to add human voice: this requires, in my idea, a third microphone... But even starting with two would be all right for now... Those recordings would not pretend to be professional, just home made for my personal tests, but stereo. I must say that the experiments I did with the above rude arrangement, i.e. two mics in common Y splitter, inserted into `mic' PC entry, are not so bad... Thanks, Rodolfo
