microphones & computer jack

[piano632]

Can anyone tell me if the standard 1/8" microphone jack on computers is intended for a mono or stereo plug?
I would assume that a microphone that has a 1/4" plug is mono. Also what impedence amount is considered OK for a computer mic jack. The mic I'm trying to use has 500 ohms impedence.

Basically I'm trying to plug a mic with a 1/4" plug into my computer's 1/8" jack. Using a stereo/stereo adapter does not work - the mic is not recognized. So I would assume I need a mono/mono adapter, or there is some other problem.

[redwudz]

I believe they are all stereo microphone inputs. You would need a 'Y' connector with a stereo 1/8" male connector to two 1/8" mono female connectors to use two mono microphones, or a adapter to combine the two channels into one if you use just a mono microphone. In your case, you would need two or one 1/4" phono jacks for your adapter. Both are fairly common adapters.

[piano632]

I bought this mic from Radio Shack, but now I'm wondering if it's even usable with a computer mic input. I think I need a mono 1/4" female to stereo 1/8" male adapter if it's going to work.

http://www.radioshack.com/product/index.jsp?productId=2123173&cp=

EDIT: On second thought, someone posted a review on Radio Shack saying it worked on their computer with the correct adapter.

[edDV]

Some other problem -- Impedance (Z) mismatch. You need a transformer to match balanced/unbalanced ~600 ohm to unbalanced HiZ.

http://www.shure.com/ProAudio/Products/us_pro_ea_audiotransformer

You would need to replace the 1/4" plug with an XLR to use this. Can't find a Shure 1/4" to mini plug version.

For XLR to miniplug
http://www.speechtechnology.com/voicerecognition.cfm?URLID=1489

[brassplyer]

Can anyone tell me if the standard 1/8" microphone jack on computers is intended for a mono or stereo plug? I would assume that a microphone that has a 1/4" plug is mono. Also what impedence amount is considered OK for a computer mic jack. The mic I'm trying to use has 500 ohms impedence.

The one that's marked specifically "mic" is going to be mono. You can use one of these gooseneck "computer mics" that's designed with the right impedance to be used with that jack. However, you haven't said what your goal is but if you care what your recording sounds like, don't use the mic jack. The onboard audio on computers is second-rate to begin with and the mic jack is notorious for being noisy and overall crap.

All hand-held dynamic mics like the one you showed a link to are mono.

If you want decent quality get a dedicated external mic pre-amp. A Studio Projects VTB-1 is a good unit and can be had inexpensively. However, don't use the 49-volt phantom power with a dynamic mic. The phantom power is only for condenser mics. A condenser mic is what you would use if you want a really crisp, "studio" sound. They're sensitive to a broader part of the audio spectrum than a dynamic mic. Dynamics are really more for live performance.

You would route the pre-amp to your "line in" jack. A single mic would only use one side, either L or R. Probably use one of these adapters that has a 1/8" stereo jack and 2 RCA jacks. I would tape the incoming line from the mic to side of the computer case for strain relief so the weight isn't resting on the jack.

[edDV]

If you want to go the mic preamp route, Radio Shack sells cheap ones like

http://cgi.ebay.com/Radio-Shack-4-Channel-Stereo-Microphone-Mic-Mixer-Board_W0QQitemZ2...QQcmdZViewItem

For little more, you can get a mid quality mixer like the EuroRack 602A (~$40 new if you shop).
http://cgi.ebay.com/Behringer-Eurorack-MX602A_W0QQitemZ260244348011QQihZ016QQcategoryZ...QQcmdZViewItem

[piano632]

I'm really only going to use the mic for spoken word, nothing critical like music. I do have M-Audio's 2496 sound card, but it only has RCA and MIDI inputs. The on-board sound card is decent enough for what I'm doing.

I guess I'll try the $3 adapter and see what happens.

[edDV]

I'm really only going to use the mic for spoken word, nothing critical like music. I do have M-Audio's 2496 sound card, but it only has RCA and MIDI inputs. The on-board sound card is decent enough for what I'm doing.

I guess I'll try the $3 adapter and see what happens.

Take it back and get a high impedance computer mic. That one is for a Kareoke machine or a garage band preamp. It won't work properly with a typical computer card input. The level will be far too low and distorted. It's an impedance issue not a connector issue.

http://www.radioshack.com/family/index.jsp?categoryId=2032388&cp=2032061.2032365&allCo...%2FMicrophones

[piano632]

The poor reviews on those computer mic's at Radio Shack don't exactly look enticing. I avoided those in the first place because they all looked cheap and I wanted something that was a step up in quality. I'm still puzzled by the one reviewer who said the mic worked on their computer with an adapter. Maybe I'll have to ask the "knowledgeable" people at Radio Shack and see what they say.

[edDV]

The poor reviews on those computer mic's at Radio Shack don't exactly look enticing. I avoided those in the first place because they all looked cheap and I wanted something that was a step up in quality. I'm still puzzled by the one reviewer who said the mic worked on their computer with an adapter. Maybe I'll have to ask the "knowledgeable" people at Radio Shack and see what they say.

Adapter = transformer or preamp

There are many good computer narration mics online.

[piano632]

Adapter = transformer or preamp

I don't think the reviewer was talking about a transformer/preamp. Here is what the review says in full:

"Easy to use for any person, just get the 1/4 to 1/8 adapter for your computer and works great. The standard 1/4 plugs into normal audio equipment too."

According to the people at Shure, impedance should not be a problem:

"Professional microphones typically have an output impedance of less than 600 ohms and most sound cards have an input impedance of 600 to 2,000 ohms, so impedance is not usually a problem."
http://www.shure.com/ProAudio/Products/us_pro_ea_connectingmics

The only problem may be the signal level.
The sensitivity rating (@ 1kHz) for the mic I have is:
-72±3dB (0dB=1V/Microbar)
So if anyone could translate that into a mv signal level, I'd be grateful to know.

[piano632]

Well, the microphone works on my old computer with the 1/4" to 1/8" adapter. It still isn't recognized on my newer computer however.

But now I have another problem. Before I bought this mic I had tried using a webcam mic. The audio on the webcam was decent for the first min. or so then I would hear random static pops throughout the rest of the recording. I thought maybe the mic was defective since someone mentioned having the same problem with that particular webcam. So I bought this new mic hoping it would fix the static popping sounds but apparently it's still happening. What could be causing this with 2 different mics on 2 different computers? Lowering the volume level does not alleviate the problem.

[brassplyer]

Well, the microphone works on my old computer with the 1/4" to 1/8" adapter. It still isn't recognized on my newer computer however.

But now I have another problem. Before I bought this mic I had tried using a webcam mic. The audio on the webcam was decent for the first min. or so then I would hear random static pops throughout the rest of the recording. I thought maybe the mic was defective since someone mentioned having the same problem with that particular webcam. So I bought this new mic hoping it would fix the static popping sounds but apparently it's still happening. What could be causing this with 2 different mics on 2 different computers? Lowering the volume level does not alleviate the problem.

I doubt that the problem is the mic, there's no reason that I can think of that it would be fine for a minute and then cause problems on the kind of mic you're using. It's not like it has tubes or involved electronics that might heat up & go bad. I'd look at the app you're using or something that's not set right. - a resource conflict, etc. What app are you using to record your audio/video?

You said you have the M-Audio 24/96, right? Why would you use your POS onboard audio if you have a real audio card? I would use that and disable the onboard audio. Do whatever is needed to interface your mic, or a better mic to the M-Audio card. Betcha your troubles would go away.

[piano632]

I'm using Windows Movie Maker to record spoken voice (and I also tried Cyberlink PowerCinema and got the same result). I have the M-Audio Audiophile 2496 card on my newer computer along with a C-Media A97 sound card built in. My older computer only has an Intel built-in sound card. I'm really puzzled by this since there is nothing in common between these 2 setups that would cause the same problem. I'd love to record thru the M-Audio card , but it only has RCA and MIDI inputs.

I did try disabling the on-board card when using the webcam thru USB but the static still happens exactly the same. I think the newer mic is a little better with the static but I have to crank up the input volume to max.

[brassplyer]

To clarify, you're doing strictly voice, no video?

[piano632]

With the webcam I tried it with and without video. Obviously the mic is audio only. I'd hate to have to buy more equipment since this only for YouTube, so the sound is going to get degraded anyway.

[brassplyer]

With the webcam I tried it with and without video. Obviously the mic is audio only. I'd hate to have to buy more equipment since this only for YouTube, so the sound is going to get degraded anyway.

And you say you'd done both direct to the mic in jack and via USB? The problem manifests itself either way?

Have you ever recorded using an app like Soundforge or Cakewalk?

[piano632]

And you say you'd done both direct to the mic in jack and via USB? The problem manifests itself either way?

Yes, both ways. That's what makes it all the more confusing. The static isn't overpowering, but just enough to be annoying. And why is it fine for the first min. before the static starts and exactly the same way on both computers with both mic's?

[brassplyer]

The answer is obvious.

Your computer is haunted.


I've posted your issue on an audio forum and see if anyone has any suggestions.

[ahhaa]

One suggestion- those combo headphones w/mic, made for speech recog software, call center telephony,etc. Wired versions are cheap ($10 & up) and specifically designed for the computer cards. The popping may be your AGC (Auto Gain Control); try testing the mic with some background sound to keep it from peaking the gain.

[piano632]

AGC seems like a logical explanation, if that is the problem. But how do you turn it off? I don't really notice any changes in volume level that would suggest AGC is taking control. Assuming it is AGC, wouldn't that mean that any other mic connected to the same sound card would do the same thing? I'll have to do some testing on this when I have time.

[brassplyer]

Something very basic I neglected to suggest. Do the computers you're using have antivirus installed? If so they need to be disabled when doing any recording. Popping in the audio is a classic symptom of antivirus interference.

[piano632]

Do the computers you're using have antivirus installed? If so they need to be disabled when doing any recording. Popping in the audio is a classic symptom of antivirus interference.

My newer computer does, but the older one does not. In fact, the older one has only a few things installed/running. The only thing the 2 computers seem to have in common is they're both running Windows XP SP2.

The only other thing I can think of is maybe a grounding issue.

[brassplyer]

[quote="piano632"]

My newer computer does, but the older one does not. In fact, the older one has only a few things installed/running. The only thing the 2 computers seem to have in common is they're both running Windows XP SP2.

I don't think you can blame XP per se. Lots of people use it with success for recording audio/video. I'm guessing something that may be set wrong.

Going to the RCA in of the M-Audio card isn't a big issue. You need a mic pre - that cheap Behringer that someone mentioned isn't as good as the Studio Projects VTB-1 but it will get the job done and it's simple to use. Get some inexpensive dynamic mic that has an XLR connection, hook it up to the mic pre - again NO 48-V phantom. You can buy this stuff ultra-cheap on ebay or if you don't want to wait, go to your local Sam Ash, Guitar Center, wherever -and you can have it in your hands and installed within the hour. This is stuff any place that sells audio gear is going to have. I've got an inexpensive Radio Shack dynamic mic and it's fine - made by Shure. However, I wouldn't go near their mic pre's or any of their "pro audio" interfaces. Dubious quality and you'll be paying way too much.

Hook it up to the M-Audio - onboard sound disabled in the Bios of course - and see if the problem persists. You can also get updated drivers at M-Audio, though the out of the box drivers work for me.

I have a 2496 and have also used a Soundblaster Live EX-Platinum on my current machine with XP SP2, have never experienced the issues you're referring to. Not to say that I discount your problem, but that I don't think the O/S is to blame.

[piano632]

I tried using Audacity to record from a CD player into the M-Audio card's RCA inputs and didn't hear any static pops this way...so it has to be the mics or the built-in sound cards that are the culprit.

[edDV]

I tried using Audacity to record from a CD player into the M-Audio card's RCA inputs and didn't hear any static pops this way...so it has to be the mics or the built-in sound cards that are the culprit.

The M-Audio 2496 is an unbalanced line level I/O card without mic inputs. To step a low impedance mic up to line level you need a mic preamp.
http://www.m-audio.com/products/en_us/Audiophile2496-main.html

If you want to stay in the M-Audio range, they make these mic preamps. If you don't want to spend the bucks follow advice above with the Eurorack or other.
http://www.m-audio.com/index.php?do=products.family&ID=preamps

If you installed the drivers, you should find the M-Audio input under Vista Sound inputs or for XP under "Sounds and Audio Device Properties".