Author Topic: dual microphone input  (Read 10686 times)

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jkubie

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dual microphone input
« on: March 04, 2008, 04:43:51 PM »
I'm looking for suggestions to get dual (cheap) microphone input for display in SignalScope. The critical issue is to be able to separate the microphone inputs and compare signals from a common source. This is for teaching purposes, to display time lags and amplitude changes, so the quality is not very important. (Did I say cheap?)
For example, its not clear if the Griffin iMic can be adapted for two micorphones. Another possibility would be to plug in two griffin iMics, each with its own microphone, but its not clear if this would cause my powerbook to self-destruct or whether SignalScope could simultaneously display both inputs.

Any feedback or suggestions is greatly appreciated.

john kubie

FaberAST

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Re: dual microphone input
« Reply #1 on: March 04, 2008, 06:45:02 PM »
John,

You could use two iMics to get two mics into SignalScope. However, you would have to make the two iMic input devices into an aggregate device in Audio MIDI Setup.

Depending on what kind of mics you use, and what their power requirements are, if any, it may be easier just to route one to the left input and one to the right input of your Mac's built-in audio input jack. If, for some reason, you can't use your built-in input, you could use a single iMic in the same way. Two inexpensive Radio Shack electret mics (typically battery powered) and an appropriate adapter could do the trick nicely.

Ben

jkubie

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Re: dual microphone input
« Reply #2 on: March 04, 2008, 07:07:59 PM »
Thanks for the tips, Ben.

Sorry for my ignorance.

If I read you correctly, the audio input jack, although a single jack, supports 2 inputs.

Is the jack the same as a headphone jack? Am I looking for a connector that is the same as a headphone connector? Will such a connector keep the 2 mics separate and be seen by SignalScope as 2 inputs?

Thanks, in advance.

john

FaberAST

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Re: dual microphone input
« Reply #3 on: March 04, 2008, 08:39:10 PM »
That's correct--the audio input jack accepts stereo (2-channel) signals, typically through a 1/8-inch stereo mini-plug (the same as a typical headphone jack). You just need to use the right adapter to keep one of your mics assigned to the "left" input channel and the other assigned to the "right" input channel. You can then view both signals separately in SignalScope.

Ben

jkubie

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Re: dual microphone input
« Reply #4 on: March 04, 2008, 09:28:13 PM »
thanks again, Ben.

I think I've almost got it. Tomorrow I'm planning on looking at a 4-channel microphone mixer sold by radioshack ($29). If I'm correct, this will have a stereo line out that should go into the audio input jack and be visible as 2 channels in SignalScope. Thanks again.

Thanks again,

john