One of 2 mics doesnt work on my Imac but on my Macbook

[kashshaptu93]

I have 2 different external mics and I can only get one of them to work when recording on my Imac but the other one only works on my Macbook Pro. Both are battery powered. Anyone experienced this and have a solution?

[kozikowski]

It depends on what the microphones are. What are they? Model numbers, makers, connection type.

Koz

[kashshaptu93]

It depends on what the microphones are. What are they? Model numbers, makers, connection type.

Koz

The one not working on my Imac but on my Macbook is a MAXIMAL M998, the other working one is an AKG C 1000 S, both XLR connection.

[kozikowski]

"MAXIMAL M998" doesn't appear to exist. At least Google can't find it.

Macs don't have XLR inputs, so how did you get from the XLR on the bottom of the microphone into the computer? And where is the microphone amplifier? The signal expected at the Mac Line-In is about a volt. The signal from a microphone is about a thousand times smaller than that -- and I'm not exaggerating.

If either of the computers worked, the signal would have been very small and noisy. (I tried this once just to see what would happen. I should have recorded it). If you have a bad or wrong adapter, the signal would have been zero.

You're plugging into the connector labeled with two black arrows and a circle, right? That connector handles analog stereo Line-In and S/PDIF optical digital. Neither of them is mic level.

Koz

[kashshaptu93]

Yes, I forgot to say: I connect the mics with a XLR to mono jack cable with an adapter to go in to the mini jack input on the computer. With "microphone amplifier" I am not sure what you mean, but the non working MAXIMAL M998 mic (non working only on the Imac) uses a single 1.5 volt battery which is placed in the handle of the mic. The mic that works (AKG C 1000 S) uses a 9 volt battery. The signal is very strong and without any noise what so ever where it works with both mics.

Thanks for helping out.

[kozikowski]

I need to dig more into the instructions. You are plugging into the Mac Line-In, two black arrows and thin circle, right?

I really need to take a picture of that.....

Koz

[kozikowski]

MAXIMAL M998

Point to a web site where I can read about this microphone.

Where were we? You were going to tell me that you plugged your adapter into the Mac Line-In, the left of the two round connectors.

http://www.kozco.com/tech/audacity/pix/MacLineIn.jpg

Koz

[kashshaptu93]

Yes, I plug in into the line in (2 arrows and a circle) as the picture shows. But on my mac book pro where this Maximal M998 (condenser cardioid) is plugged in, the line in and line out is one and the same. I have to configure "sound" to have it work as line in. HERE the microphone works just fine. But not on the Imac in which I have the mini jack adapter plugged with the cable all the time in the input, I only switch the mic, not the cable. So the AKG mic works in this case but not the MAXIMAL.
I have some information about the MAXIMAL mic: On the box it says: Electret Condenser Microphone. Impedance: 600 Ohms. Frequency response: 30-16,000 Hz. Polar pattern: Uni-Directional. Battery: AA type (UM-3 1.5 volt).

AND THE SPECIFICATIONS:
Frequency response: 30-16.000Hz,
Power supply: Internal 1.5 volt battery (size AA),
Amplifier: I C Impedance converter,
Polar Pattern: Uni-directional
Output level: (1,000 Hz) -66 dB
Generating Element: Electret condenser
Output Impedance: Low Z
S/N Ratio: Greater than 44 dB
Equivalent Noise Level: Less than 30dB SPL
Current Consumption: 200 uA _+ 50 uA (+ sign over the line before!)
Battery life: 7000 hours in continuous operation
Cable: 15.ft., Cable

I hope this helps!

[kozikowski]

I think you have three problems, none of them to do with Audacity, but that's OK.

The AKG without question has a full balanced broadcast microphone output signal(s) on its XLR connection. The restrained cost microphone without the web site may have fudged a little and only provided parts of the balanced output signal -- because it's really cheap to do that and most of the time, it doesn't make any difference at all.

You can't actually directly adapt a balanced audio signal to the unbalanced connection in the Mac. You can fudge it (there's that word again) by clever cross-wiring inside a simple audio cable. Good unless you need really long cable runs or have a noisy environment.

You can't actually switch one connection between Line-In and Line-Out, but you can fudge it (are you seeing a pattern here) by clever manipulation of the Mac electronics.

It's when all these clever manipulations and fudge factors line up that the microphone fails. If this were a full broadcast facility you wouldn't have any of these problems.

I'm really interested in the Macbook Pro. It always rings bells when Apple changes the audio system in one of their machines. The problems ripple far and wide. Is it really a Pro? How old is the MBP and which one? 14", 15", 17?"

Apple > About This Mac > More Info > Hardware > Model Name, Processor, Speed, etc.

I need that to see what they did to the sound channels.

Koz

[kozikowski]

Yes, I forgot to say: I connect the mics with a XLR to mono jack cable with an adapter to go in to the mini jack input on the computer.

I was talking this over with one of the techies here and we want to know a lot more about that adapter. How would I buy one?

Koz