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Topic: Microphone to sound card (Read 2576 times) previous topic - next topic

Microphone to sound card

This was a basic enough question that I was surprised not to find it answered in the archives. In fact, this is the first time I did not find the answer in the archives, forcing me to go ahead and post for the first time.

I consider the basic computer microphone pretty much a joke. At least, it seems like a telephone pickup would produce a wider bandwidth. Anyhow, I sat down with a real microphone and a 1/4 to 1/8 adapter and tried plugging in, to discover I received no signal into my computer.

A closer inspection revealed that the computer mic has a stereo plug! The adaptor of course was taking a normal mic male down to a mono 1/8 male, and that was not the appropriate input.

So, am I trying to do something the wrong way here, or should I just keep looking for an appropriate adaptor? Do I need an additional piece of equipment (such as a preamp)?

If you are wondering "why in the heck would you want to do that?" by the way, I was trying to mix audio captures (of acoustic instruments) with midi files from "Noteworthy" using "Digital Orchestrator." It works great, except the audio quality of an acoustic instrument on a computer mic is only useful as an unusual sound effect.
Alternate question: is there a forum out there as knowledgable as this one, but focused more on the hardware then on use of Noteworthy and composition, where I ought to be posing this question. Either answer would be appreciated.

Eric Fretheim

Re: Microphone to sound card

Reply #1 –
Getting high quality recordings is a science that takes much skill to master, but is not too hard to get decent results with some basic computer equipment. You can get as much out of it as you put into it.

For starters, you can find some tidbits in this forum by searching for something like "line level" and picking subjects that look promising. Here are a few I found:

https://forum.noteworthycomposer.com/?topic=1083
https://forum.noteworthycomposer.com/?topic=1216
https://forum.noteworthycomposer.com/?topic=1254
https://forum.noteworthycomposer.com/?topic=1269

If you want go deeper, you might want to lurk through an audio recording newsgroup and see what you can learn. There are some good usenet newsgroups that discuss audio techniques. Be advised that some pro/semi-pro audio discussion groups expect a high level of competency from those that ask questions.

Re: Microphone to sound card

Reply #2 –
If the only problem were the stereo/mono issue, the result would be that you would only be able to record in the left channel, since generally tip=left, ring=right. So I suspect something else is awry. Things to check:

1: (D'oh! department) - is the mic level unmuted and the slider turned up in the mixer applet or Windows native volume control? (The little speaker icon in the taskbar). Is is set as the source for recording? (Options | Properties | Adjust volume for recording)

2: Is the adaptor working? I work at a shop that sells these, and it's surprising how many are bad right out of the bag.

3: Are you sure your mic input is stereo? That would be unusual, on most cards the mic input is mono, with equal signal applied to both channels when recording in stereo mode.

4: If it's a condenser mic, is the battery good? Is it turned on? (Sorry if some of these suggestions seem insulting, that's not my intent. Just covering all possible bases.)

5: If it's a dynamic mic, is it a high-impedance type? Or, if it's a low-impedance type are you going through an appropriate matching transformer? Is your soundcard configured for the appropriate mic? (Many of them have a jumper setting on the card itself, others allow a 20 dB boost for dynamic mics in software - i.e. the mixer applet.)
All that being said -- I've found that the mic inputs on sound cards generally leave a lot to be desired; the signal-to-noise ratio - phrased bluntly - sucks. You'll probably get much better results going into the line-level input; this implies that you'd need an external preamp or mixer. You can get pretty good little 4-channel active mixers that run for hundreds of hours on a 9V battery for around $30 these days (check out music stores if your Radio Shack doesn't carry them).

It /is/ possible to get good recordings without nearly as much fuss as it takes to run a conventional multi-track recorder. Watch your levels, too high = distortion, too low = excessive background noise. Experiment with mic distance; too short = boomy, popping "p"s, possible distortion, too long = thin and reedy, possibly excessive "ambience".

HTH

Fred

Re: Microphone to sound card

Reply #3 –
Noteworthy Online: Thanks for the links: I will be looking over them shortly.

Fred:
Quote: "1: (D'oh! department) - is the mic level unmuted and the slider turned up in the mixer applet or Windows native volume control?"

I checked the software possibilities by switching out between the typical computer mic and my good mic. Computer mic = signal, good mic = no signal. Checked the mic by hooking it up to my wife's (shudder) karaoke, where it delivered a good input.

"3: Are you sure your mic input is stereo?"
Dunno, but I had been assuming that a standardized computer mic which has a stereo plug is intended for a like socket in a standardized sound card. I suppose this isn't necessarily a good assumption.

Won't copy all of 5, but the mic is a low-impedance dynamic mic with what I assume to be an inline transformer in the detachable patch cord. At any rate, it plugs directly into home stereo equipment with good results.

Having said all that, I'm now going to go back to 2, "is the adaptor working?" I took out a multi-meter, and was bemused to discover that, although the unattached adaptor plug had infinite resistance between rings, and the mic plug was a little over an ohm, the adaptor plug when attached to the mic had about .3 ohms. Finally I figured out that something was shorting. I played with it and found that, although the mic plug will seat all the way into the adaptor, pulling the plug out about 1/2 inch delivers the 1 ohm I wanted to see. Plugged it into the computer in this position and bingo, the mic worked fine.

This tells me that the adaptor is either actually meant for some other extremely similar plug (I'm not very familiar with sound equipment standards, but I have trouble believing this), or is defective.

Anyway, I did a quick tryout recording and discovered that my rig does in fact much improve the sound, but not to the level I had hoped. I'm attributing the shortfall to your claim that the mic input on my sound card is probably not very good. So, next time I'm at RS, I will look into the cheap mixer as you suggested. Thanks.

Eric Fretheim
 

Re: Microphone to sound card

Reply #4 –
> This tells me that the adaptor is either actually meant for
> some other extremely similar plug (I'm not very familiar with
> sound equipment standards, but I have trouble believing
> this), or is defective.

Aha. The old "plug the adaptor out a smidge" trick. No, there aren't different-but-similar plugs, just poor adherence to standards. The shape of the tip seems to matter, i.e. whether it's spherical or tapered.

Congrats on getting it figured out!

Fred