Can't choose "mono" option

Hi, everyone:

I am using a a condenser mic and TubePre preamp, which is running into a Alpha Lexicon In/Out unit. To make it a bit more complex, I’m on a mac (OS X) running Parallels 7. Here’s what’s happening:

  1. When I record my audio into the screen recording software, the playback comes only through one headphone.
  2. When I record into Audacity and choose “mono,” the audio signal is very, very faint and no waveform to speak of is created. It is recording something, though. Have to really crank the volume to hear it. If I choose “stereo”, the waveform and levels are great, but the playback comes through just one headphone.

Any thoughts? Thanks so much. --Daniel

The Lexicon alpha is a 2 channel device. The first channel is for instrument input and the second for microphone.
Alternatively it can be used as stereo line level input.

In normal stereo there are two audio channels. The first channel is the left channel and the second is the right channel.

Audacity does not have “channel mapping” so it cannot switch channels 1 and 2 around. If you record 1 channel (mono), Audacity will record the first channel of the audio device (which on the Lexicon alpha is either the instrument channel or the left line input). If you record 2 channels (stereo), Audacity will record the first channel as the left channel (the upper channel in the stereo waveform) and the second channel as the right (the lower channel in the stereo waveform).

As the Lexicon alpha only provides a microphone input on channel 2, the only way that it can be recorded is to record 2 channels (stereo) and then after the recording is complete, split the stereo track into 2 mono tracks and delete the unwanted track.

The very quiet audio is called “cross-talk”. It is caused by a small amount of the channel 2 signal leaking through to channel 1 within the Lexicon alpha.

Some programs (such as Sonar, Reason, Logic, Cubase…) allow you to “map” the input channels, so that in effect you can treat channel 2 (the mic channel) as if it were channel 1 and then record it in mono. If you would like to vote for that to be developed in Audacity, let me know and I’ll add your vote.

Thanks, Steve: another question or two, if you don’t mind:

  1. When just using the condenser mic and TubePre preamp (no alpha), why, when I record into my screen recording software (I do online training) does the playback only come through one channel? I bought the alpha lexicon to help with this issue, but I’m guessing it’s not. Thanks, Daniel

I don’t know what “screen recording software” you are using, but I’d guess that it is the same reason. Microphones are mono (unless they are specifically a “stereo microphone” but those are really two microphones stuck together in the same case). If your software is trying to record stereo (2 channels) then it is likely to pick up the mic on one channel and nothing on the other.

Splitting stereo tracks in Audacity is easy. See here:

If you have a MacBook Pro or other portable Mac, the built-in microphone can be made to appear as two channels, it doesn’t force you to record it mono. It’s still not stereo. There still only one microphone behind the grill, but it doubles up automatically to put something in both channels.


Thanks much, Steven and Koz. I’m learning a lot. I am curious:

  1. If most microphones are mono, why is my screen recording software (Articulate Replay) trying to record in stereo? This also occurs when I hook up an external condenser mic to my camcorder. I’m just curious.

  2. I bought the alpha lexicon primarily so I could use headphones when doing my voiceover. However, it also comes with Cubase, so I guess the next thing for me to do is to (as Steve suggested) map

    I noticed this same thing happening (playback just coming through one speaker) when I hooked up an external mic to my camcorder. The Alpha Lexicon comes with Cubase, so it seems the first thing I should do is try (as Steve suggested) to “map” the input channels so I can treat channel 2 (the mic channel) as if it were channel 1 and then record it in mono. Would this likely solve the issue of my screen recording recording in stereo and having playback in just one channel?

when I hooked up an external mic to my camcorder.

Dig in your instructions. Does your camcorder feature provisions for a stereo microphone? Many camcorders do. So as far as the camcorder is concerned, you connected a stereo microphone with one channel really, really quiet. We had one camcorder at work that insisted on doing that, so I designed and built an adapter that fed the microphone down both channels. It was wasn’t elegant, but we weren’t shooting breaking news in a brush fire, so it worked for us.

You can unconditionally produce a balanced track by using a single microphone and a sound mixer. The mixer can “assign” or fade the microphone to both left and right and the show appears as stereo with the same thing on left and right. That’s how I deliver a voice track to the video editors. I understand it’s “mono” in that it’s only one voice, but the rest of their show is stereo and it’s less stress if I do it that way.

You can do that with the Mac built-in microphone as well. You can set it to appear on left and right of a stereo show by settings in the Mac System Preferences, in essence, a built in mini-mixer.

Other variations take reading the instructions. We know that some microphone amplifier/adapters force stereo and always put one device on the left and a second device on the right. I believe the Focusrite Scarlett 2i2 does that. It seems to be a two-channel mixer, but it’s no such thing. The two microphones are always split left and right and you have to straighten it out in post production.

I don’t know where the Right Channel Microphone is coming from. If you plug a mono microphone into a plain soundcard it will normally appear on the left or mono. Your Mileage May Vary.

my screen recording software (Articulate Replay) trying to record in stereo?

Because it’s simple? If you record a mono show in stereo, you can recover from that in post production. If you record a stereo show in mono and thereby lose one side of the recording, there is no recovery. That’s the end of the show.

Have you been in the instructions and presets for your software? We can bore you to tears about Audacity, but we’re a good deal less entertaining in other people’s software – and we don’t supply hardware at all.


Thanks, Koz, for helping me understand this.

If the Cubase app that comes with the alpha lexicon proves a hassle, any straightforward mixers you recommend? Just doing voiceover, so the simpler the better, I think. And oh, yeah, it’d be great to have a headphone jack. Thanks, Daniel

Hi, Koz and Steve:

So I’ve done some fiddling, and the audio still is only coming in on the LEFT channel. Would a mixer solve this problem? That is, could I force the audio down both channels? Thanks so much. --Daniel

With a (stereo) mixer you could force the audio into both channels, or just into left channel. The thing that is causing the problem is that the mic channel on the Lexicon Alpha is the second (right) channel, but with a mixer you can send a mono output to the left “Line input” of the Lexicon and record in mono, or by sending the mono signal to both Line inputs you can record 2 channels (still mono, but 2 identical channels).