Vocal Effects: Problems?

Started by Albot, December 04, 2007, 05:51:37 AM

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Albot

Hello i would like to make a effect for vocal use.
Now i take for granted that you put the effect inbetween the mike and the PA because that's the setup we have.
I can see a couple of possible problems like if i want a balanced input/output (i have no idea how this works), impedance, gain and phantom power.
We don't currently use phantom power (also something i don't know very much about) but we use xlr -> phono plug becuase that's all the PA has.
We do however have a effects loop on the PA but i would like to know if it's possible to make effects that are plugged in between mike and amp/preamp.

Now i realize i should probably just read about how PA's work and that's what I'll do but I'll let the post be here incase someone needs to read it later on.

Cool, Thanks.
/A

rubix cube

You would probably need a mic preamp first, then the effect, then an output stage to feed either a mic or line input on the mixer. The effect part will probably require an unbalanced signal at a suitable level (i.e the mic signal will have to be amplified and debalanced).  If you wanted the output from this to plug into a mic input on a mixer, you would need to have an output stage like a DI box- to convert the signal back to a balanced, smaller signal with appropriate impedence for a mic channel.  If you wanted to plug into a line input on the mixer, you may just need to convert the signal to a balanced one.  As for phantom power, I guess this would probably have to be an integral part of your preamp, as I'm not sure whether you could use the phantom from the original mixer (if it has it).

It's pretty complicated- particularly if you wanted balanced inputs/outputs and phantom power.  If your current setup only has phono connectors for mics, get a new mixer first!


Albot

Ah alright!
Thanks for the quick and informative answer!
I'm going to lern alot more about that stuff before even atempting it then.
Shouldn't be a problem connecting guitar type effects to the mixers effects loop though!?

rubix cube

That'll probably be fine, as long as the signal from the loop isn't so loud that it overloads the effect!

Aren

Actually, this task may not be as complicated as you think.
Most PA mics are dynamic, and don't require phantom power at all. If your PA mixer only has 1/4" inputs. it cannot supply it in any case.
What you have to do, is run the mic through a impedance matching transformer (Radio Shack has a decent cheap one, housed inside an XLR-1/4" adapter. part #2740016), and then you can probably connect your mic to any guitar effect you'd like. I'd start with a booster of some sort, or a compressor, and go on from there. If you ever get a PA with decent XLR inputs, all you have to do is add another transformer at the end of the chain, to convert the signal back to a balanced, low impedance one.
Good luck!