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Gear / Technical Help => Microphones & Setup => Topic started by: rasta on October 26, 2008, 11:01:08 AM

Title: Mic cable length
Post by: rasta on October 26, 2008, 11:01:08 AM

How long is too long?  I'm trying to mount some 4023's about 50 ft from my m148 and 722.  Will there be any signal degradation or other things for me to worry about?

Title: Re: Mic cable length
Post by: rasta on October 26, 2008, 11:32:18 AM

Thanks Moke.

Title: Re: Mic cable length
Post by: DSatz on October 26, 2008, 06:30:49 PM

Hi. Cables for low-impedance balanced microphones (driving balanced preamp or recorder inputs with 1000+ Ohm input impedance) can usually be several hundred feet long with no audible problem.

The main determining factors are the capacitance of the cable (in pF per foot or per meter between the two modulation leads), the output impedance of the microphone, and whether or not the microphone has a transformerless output circuit. For driving long cables a transformerless output is greatly preferable, with as low an output impedance as possible.

If the cables are too long or have excessive capacitance, you can run into high-frequency losses. For microphones with output transformers there can also be a reduction in headroom (maximum undistorted sound pressure level) at high frequencies--or conversely, excessive distortion when trying to use the microphones at levels of high frequency sound that would be OK with cables of more ordinary length.

--best regards

Title: Re: Mic cable length
Post by: cybergaloot on October 27, 2008, 03:16:57 PM

What about cable length for sound board pulls? I'd suspect they could be fairly long since the signal strength is quite a bit higher than with condenser mics. What sort of cable would you use if you were using the tape out RCA of the board? I bought some RCA>XLR adapters thinking standard mic cable would be best.

I'm planning on getting a R-44 and the soundboard in my favorite club is probably 75' away once you run it around the room in a safe way.

Title: Re: Mic cable length
Post by: cybergaloot on October 27, 2008, 04:58:52 PM

Quote from: mshilarious on October 27, 2008, 04:48:55 PM

Unless your RCA-XLR adaptor includes a transformer, I would guess 75ft could be problematic.

For the price I paid I'd highly doubt there's a transformer, well and the size & weight too. Is there maybe an adapter box that would help?

I really want to go to four channels (two soundboard) in this club. The vocals sometimes get drowned out by the guitar amps. Actually I don't need two soundboard cables since its being run mono. I could play around with the fourth channel for things like a spot mic.

I'm also considering just moving my pair of mics to stage lip or overhead. That's all a ways off time-wise though.