Using mic on wireless guitar systems / ohms

[tremendo]

I have a Line6 relay G50 with 2 transmitters that I am no longer using, but I wanted to hang onto. I am now using the Shure GLX-D that I am happy with. And I do meetings where I use ear set mics. So I bought one with the correct TA4f connector. It works, but with very low volume compared to background noise, to the point it's not functional for me. The mic is listed at less than 200 ohms, the G50 is way above that. Is this something that could work, did I just get the wrong ohm mic, or was this just a bad idea? The Shure headsets for the Shure system show 600 ohms or 2400 ohms. Here is the info from my earset:

 

 

 

Sensitivity: -42db±2db

 

Frequency range:30-18KHZ

 

Output impedance: ≤200 Ω

 

Standard operation voltage:1.0V-10V.DC

 

SNR:>58db

 

 

 

thanks for any help!

[spentron]

That's a amplified mic so it won't be affected tonally by a high impedance load, and yet loading it down with a low to high impedance transformer could affect the sound, though probably not. Such transformers usually masquerade as XLR-> 1/4" adapters and do raise the signal level. Otherwise you'd need an active booster. If you were singing into this mic it would loud enough and a transformer would just cause distortion by making it too loud ...

[WRGKMC]

The transmitter is instrument level which is lower then normal mic level.

If the transmitter was line level input you could use a small battery operated mic preamp to bring the mic level up to line level.

The problem is your transmitters Instrument level is in between mic level and line level so boosting the mic to the proper gain is

not as easily accomplished. You may find a preamp that normally gains a mic up to line level then attenuate it.

 

Without a preamp the mic is just isn't going to produce enough gain for the transmitter. You need about a 10db boost to get the signal loud enough.

 

+4 dBu is "professional" line level, common in modern pro recording gear, and it is about 1.25 V.

0 dBv is an average line level, typical output from rackmount guitar/bass preamps.

-10 dBv is "consumer" line level, common with older and cheaper recording gear.

-20 dBu is roughly in the neighborhood of a typical instrument's output.

-30 dBu is again in the neighborhood of a typical microphone or DI box's output.

 

You also have an issue with the receivers output level. The receiver likely has an instrument level output designed to plug straight into a guitar amp. PA mixers often have a high impedance input but they may be weak for an instrument level input so additional preamplification may be needed there too.

 

In my opinion, you just have the wrong gear to do the wrong job. By the time you get both the Transmitter input and receiver output levels right by adding additional boxes you're essentially dealing with a rig that may not even produce a high enough fidelity signal for a mic. Mics need a full 20~20Khz response to sound good through a PA or record. Guitar gear only needs 150~6K .

 

My best suggestion is trade the guitar transmitter for a mic transmitter or sell the one and buy the other. I should note, There's a reason why many decent Mic transmitters cost more, its because they do provide a higher fidelity.

 

 

[tremendo]

Thanks so much guys for the replies and explanations. So I tried more configurations and I found this:

 

1) Just as a test, a guitar cord through the same setup with the line6 Relay G50 wireless into the PA sounds quite a bit louder and has no background noise even at full volume on the guitar.

2) I switched wireless units to try my Shure GLX-D, as it uses the same TA4f connector. It works fine with the Earset mic with no background noise. The mic sounds decent, it's an omni ear set, so will not get too loud before feedback, but it works as I had hoped.

3) I tried a regular SM58 via various adaptors via the Relay G50, and the volume was low, but no background noise. The very high background noise came only with the Earset mic and only when using the Line6 wireless.

 

Final Results:

With everything else the same, I switched back and forth multiple times between the 2 wireless units, Shure GLX-D & Line6 Relay G50. For a guitar into the wireless and into the PA they both sounded the same. Also the same with an SM58 with various adaptors. But my Ear Set mic sounded and worked fine through the Shure wireless, but never could get rid of massive background noise through the Line6 wireless. I imagine the Shure automatically adjusts for different levels/ohms, or something, making it work. I also think the transmitters are the same for both for instruments and mics, so the culprit may be the Line6 receiver. Although I had hoped to use the Line6 wireless for the mic, I won't be playing guitar and speaking in conferences with the Ear Set mic at the same time, so I believe I can just use the Shure wireless.

 

 

[Phil O'Keefe]

What is the make and model of the "Ear Set mic"?

[tremendo]

What is the make and model of the "Ear Set mic"?

 

No brand: From China, ordered from manufacturer. 1st time I've gotten something "musical" like that, was kind of a test.

[WRGKMC]

You have all kinds of wireless head worn mics being sold. Dynamic, Electret, Condenser. Some run on 5V phantom from a computers mic input, Some require other phantom power voltages. You have different impedances, signal strengths and connectors as well as huge differences in quality. You really have to investigate the details to make sure they all work.

On top of that the transmitters and receivers can be tuned to different frequencies and the receivers are usually mated in radio signal strength of the transmitter. Shure makes some good gear but it's going to sound best with all the gear matching. They make some generic replacement mics for those systems but to be honest I doubt they'd be superior to having all the matching components to the system, even if they sell for much higher prices. I got burned myself trying to go the budget route and unless I come across a high quality setup I wouldn't waste my money going budget again. Either the mic sucks or the transmission range is limited making the setup worthless.

 

[WRGKMC]

You have all kinds of wireless head worn mics being sold. Dynamic, Electret, Condenser. Some run on 5V phantom from a computers mic input, Some require other phantom power voltages. You have different impedances, signal strengths and connectors as well as huge differences in quality. You really have to investigate the details to make sure they all work.

On top of that the transmitters and receivers can be tuned to different frequencies and the receivers are usually mated in radio signal strength of the transmitter. Shure makes some good gear but it's going to sound best with all the gear matching. They make some generic replacement mics for those systems but to be honest I doubt they'd be superior to having all the matching components to the system, even if they sell for much higher prices. I got burned myself trying to go the budget route and unless I come across a high quality setup I wouldn't waste my money going budget again. Either the mic sucks or the transmission range is limited making the setup worthless.