RCA, 1/4, or XLR?

M

Middleman3

New member
Hey. Quick Question. . . .

I've got a 8 channel mixer with my drums going to another mixer as a submix. I have the option of using RCA, 1/4" or XLR, and Im wondering which one would give me the best sound quality. Thanks.
 
Okay. All things being equal, there's no difference in sound quality on any of those three. However, things are not necessarily equal.

An unbalanced feed is far more susceptible to outside interference than a balanced one. The RCAs are definitely unbalanced so use them only as a last resort, particularly if the cable run from your sub mixer to the main mixer is fairly long.

Quarter inch can go either way. A TS connector (Tip-Sleeve--the ones sometimes called mono) are unbalanced. The TRS variant (Tip-Ring-Sleeve--the ones often called stereo but that's wrong in this case) are balanced and fine.

XLR is pretty much always balanced (unless wired up in a non standard way) but might present a different issue. Many mixers (but not all) use XLR for microphone level inputs only--others can take mic or line via XLR. It will depend on the main mixer in use whether this is an issue for you but, if this is the case, the main outs from your submix will almost certainly be line level and could overload a mic level input via XLR.

So...definitely try to use a balanced feed but the exact choice will depend on what make and model your two mixers are.
 
Sound on Sound magazine had an article on this a few years ago.

They found xlr, 1/4 and rca had similar electrical resistance and area of contacts so no quality differences there.

They DID find that 1/8" plugs had far higher resistance and less area of contacts so they suggested you stay away from them if possible.
 
OP needs to be more specific. I'm guessing from the original post that we talking the connections for the runs form the 8x? to the next board? Also, OP needs to tell us if the XLR's on both boards are "mic" i/o or "line" i/o.

There usually is no inherent advantage or disadvantage to balanced vs. unbalanced lines. It depends on the application Balanced lines are generally preferred for longer distance cable runs.

Additionally, balanced line level is usually about 4x hotter signal ("+4dBu") then an unbalanced line level ("-10dBm")

From what I can assume from OP's post, he is running his drum signals (mics? line outs from drum synth? ) to an 8 input mixer feeding another board. I do have a submixer with a pair of line level XLR outs, (in addition to RCA) so it's possible the XLR outs are line level and not mic level. If the second boards XLR's are mic inputs that won't work, the +4 signal will be way too hot..

If those are mic level, I think it would be better to use the unbalanced line outs to unbalanced line ins, because, more likely then not the submix is attenuating the signal to get it to mic level, and then the mic input on the second board has to amplify that signal, so you're adding two gain stages. But, given the choice, as long as you're matching mic to mic or line to line, give all a try and see which one sounds the best.
 
K sorry about that. I've got 4 microphones into the XLR mic in on my mixer. Im taking that submix to another mixer. the second mixers XLR's are mic inputs, however my first mixer has a switch by the XLR main outs to toggle between the +4 and mic level.

also. It turns out all the 1/4 cables I have are TS unbalanced. its funny cuz Im always looking at my adapters, seeing TRS connections, and I never bothered to check the actual cables. I just recently learned the difference. I have a 1/8" TRS cable with 2 1/4 adaptors on it, so now thats my only TRS cable... :o I gtg shopping.

anyways, what was interesting, was that I plugged in an unbalanced TS cable to a line in on my first mixer, and its rather queit, and acompanied by a rediculous scratchy hum. Then I use my cute little TRS cable, and it sounds full and clean. I have a Mackie Mixer that totally works with Balanced and Unbalanced cables. It is used, so Im not sure if something is wrong with it or not.

Last question: exactly whats the difference between Line level and Mic Level?
 
Simply put

the electrical output from a microphone (and a phono cartridge) is very small, often measured in microvolts. It therefore needs significant pre-amplification before adding to the mixer's buss.
Pro (low impedance) microphones need to see an impedance of around 1kilohm. They will use balanced XLR circuits.

A phono cartridge needs to see 47kilohms and usually uses RCA plugs.

There are two line levels, pro and consumer.
Pro typically uses balanced circuits and TRS plugs with the signal across the Tip and Ring, with the Sleeve earthed.
Electrically it is defined as +4dBu (or dBm) which is essentially with reference to 775mV, and carries a signal measured in millivolts.
The impedance of the mixer circuit is usually 600 ohms.

Consumer typically uses unbalanced circuits and RCA plugs with the tip hot.
It can also use TRS plugs 1/4" or miniature with the Left channel going to the Tip, the Right to the ring and the sleeve carrying the joint ground.
Electrically it is at a lower level than Pro and is defined as -10dBV which is with reference to 1 volt. Again the signal is millivolts.
The impedance is usually around 10 kilohms.

A guitar is a bit like a microphone in electrical output level, but the pickup needs to see an impedance in the range 500,000 to 1 megohm. Which is why DI boxes are used.

Very simply put.

To read more, see the Yamaha Sound Reinforcement Handbook by Gary Davis and Ralph Jones.
One of THE standard texts on the subject.

SysExJohn.
 
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