Microphone problem - need HELP!

I just bought a Sennheiser e835 mic, and it’s not giving expected gain on my desktop, while it’s working fine on my laptop.

The audio-in ports (1 back and 1 front panel) on the desktop are working fine, since my simple Zebronics chatting headset mic is very much giving the expected levels on the desktop. The performance of the Zebronics is identical on the laptop as well. The e835 is giving identical level of the Zebronics on the laptop, but on the desktop the level from the e835 is hardly 50%.

Is this because the desktop motherboard is not particularly supporting the Sennheiser mic? That seems to be the only explanation, but I can’t find enough info on this. If anyone could help, I’d be grateful. The desktop MB is Intel Original GCNL945 (core2duo). Currently using onboard sound. Should I install a separate sound card - would that help? Any suggestions?

Thanks!

Thanks for giving us enough information to dig this out. Now we just have to do it.

OK. Straight dynamic microphone plugged into the Mic-In of the computer. What does the 1/8" plug look like? It’s supposed to like like this:

http://kozco.com/tech/audacity/UnbalBalAdapter.jpg

If your 1/8" connector has an extra ring in it like this:

http://kozco.com/tech/audacity/pix/RCAMiniStereo.jpg

Then that’s where your signal is going. You can’t use a straight balanced adapter to go into the sound card. A balanced microphone puts half the signal on the tip and half on the ring unless you stop it. The ring connection in a sound card is a battery connection, not a sound connection. So that signal is wasted – 50% wasted.

The top illustration carries the wiring diagram to make your own adapter. If you can break into the existing 1/8", you can move the connection from the Ring to the Shield and everything should be OK. You need to be good with soldering wires and tools. We’ve never found a commercial supplier for this adapter.

I have no idea why your laptop works. IMHO, that one may actually be broken. The desktop is working normally.

Koz

To “kozikowski” > So many thanks for the info. Yes, the current adapter is with 2 rings (stereo). I don’t think I can reconfigure the jack, but perhaps I can look for a mono adapter (could be lucky - one never knows…).

However, I can’t help but point out that this still doesn’t explain how the Zebronics Mic is working perfectly on both desktop/laptop. Both mics happen to be equipped with identical 2-ringed stereo EP jack. If the laptop audio-in port is malfunctioning and thereby somehow both mics are ‘working’ on the laptop, and the desktop audio-in is in proper condition and thus giving 50% gain on the e835 - shouldn’t the Zebronics mic give the same result on the desktop as well since the EP jack is identical? If failure of the Sennheiser mic on the desktop is an indication that the desktop audio-in is working properly - The Zebronics should also give 50% on the desktop?

Is it possible that the 6.3mm to 3.5mm adapter is faulty? It’s brand new, but who knows if it’s not defective!

I actually notice that the adapter and the EP jack on the Zebronics are not exactly ‘identical’. There’s some minute difference in construction. The adapter seems to be a half mm longer! When placed side by side, the rings on both jacks are not positioned at identical locations on the shaft - there’s a slight difference. The tips of the 2 shafts are also certainly varying in shape and size - however miniscule the variation is. Is this slight variation quite normal and OK? Please check attached photo (taken with a VGA mobile camera, so quality is bad - sorry).

Thanks!
audacity-forum_01.jpg

No message, anyone? That’s sad :slight_smile:

Well, thinking maybe it’s a port issue with the onboard sound - I also bought a very simple entry level ultra-cheap sound card for testing (Intex, an Indian ‘brand’). With this card, it’s the same result - zebronics headset mic is giving much higher gain than sennheiser. But the sennheiser gain is quite acceptable, and the recording quality is good.

However, the sound card recording is adding heavy HISSS in the background (all mics and softwares). Cannot understand why this hiss. Is this a card problem - is that card faulty!? Any advice?

I doubt that you will get satisfactory answers to your questions as the technical details of the equipment are unavailable.
However, some comments.

Not all microphones are the same and microphones will produce different results depending on what they are plugged into. In particular, the input impedance of the microphone pre-amp will affect the signal level.

Some sound cards have mono inputs, others have stereo inputs. When recording a mono source (such as the microphone) with a sound card that has a stereo input, the mono signal can be handled in one of two ways - the mono signal may be derived from just one channel from the stereo input (usually the left channel), or the mono signal may be derived from an average of the two channels.

Many cheap sound cards have very poor quality microphone inputs and produce a lot of background hiss. (My laptop is terrible).

Computer headset microphones are designed to give a high input into a typical computer microphone input. (anywhere between about 1 and 20 kOhm, unbalanced)
The Sennheiser e835 mic will be optimized to produce a high quality signal into a typical mixing console microphone input (600 Ohm balanced)

The slight difference between the length of the tip and ring isn’t a big deal. The system has a certain amount of slop built into it. However, I have had connectors with broad shoulders like the black adapter hit the side of the sound card before the gold pin gets a chance to make good contact inside the electronics.

What usually kills pro microphone connection to sound cards is the way they’re wired. Headphone or computer microphones have the sound signal between the tip of the plug and the outer sleeve.

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

Pro microphones and microphone adapters put the signal between the tip and the gold ring, not the sleeve. They don’t connect the sleeve at all, or if they do, it’s just for shielding against electrical noises and is optional. So the sound card is expecting one style of wiring and the microphone is providing the other.

No, it doesn’t work very well.

This is the style of adapter you need to connect an XLR style microphone to a sound card. It’s intentionally missing the gold ring. I made that one. They’re not common at all.

http://kozco.com/tech/audacity/UnbalBalAdapter.jpg

The special wiring is listed.

Koz