splitting mic inputs

[IA76]

Hi

 

Is there any issue with having 2 mic points going to one mixer channel as long as only one mic point is in use?

 

The cable going to the mixer input will be split off to the 2 mic points.

[david.elsbury]

Do you really mean combining from 2 sockets into one mic input on a desk?

 

That would make more sense than using the word "splitting"...

 

With modern gear you shouldn't have any problems, what sort of distances are we talking between each socket and the mixer?

[Bobbsy]

As David says, with modern gear, combining two mics into one mixer input can generally work though it's not considered good practice. However, there are a couple of issues you can get into. First, mics are generally a relatively low impendance source and the mixer input high impedance. With the wrong equipment, this can lead to the signal from one mic going up the other leg of the "Y" and into the other mic. I won't bore you with details but, as David says, this shouldn't be a problem with modern stuff but older gear might not be so happy.

 

The other issue can be phantom power if you use it since it's split two ways.

 

If we are reading your post wrong (and it IS a bit confusing), no problem splitting one mic into two inputs though.

 

Bob

[IA76]

sorry, I do mean combining 2 mic points in to one mixer input.

 

It's all modern equipment and the mic will only be connected to one of the mic points as there is only one mic.

 

Thanks for the advice.

[paulears]

Having twin cable lines to one input then using just one will work. The only downside could be you leave yourself more prone to interference pickup, as the long cable without the mic attached offers a convenient access point for all sorts of noises and weird stuff. It will probably work fine - but if the wiring then stays like this, at some point in the future somebody might connect a piece of problem kit - maybe a very noisy dimmer, near your 'open' cable and finding where it's coming from will make you scratch your head.

 

If it does cause problems, the just pull the 'open' feeder out of the splitter!

[mackerr]

Having twin cable lines to one input then using just one will work. The only downside could be you leave yourself more prone to interference pickup, as the long cable without the mic attached offers a convenient access point for all sorts of noises and weird stuff. It will probably work fine - but if the wiring then stays like this, at some point in the future somebody might connect a piece of problem kit - maybe a very noisy dimmer, near your 'open' cable and finding where it's coming from will make you scratch your head.

 

If it does cause problems, the just pull the 'open' feeder out of the splitter!

 

As long as there is a mic plugged into one of the lines, the whole circuit has that low impedance termination to reduce noise pick up. There is still the issue of someone using the extra jack without knowing the other one was already in use. Depending on the gear they may adversely effect each other, and there would be no separate control of each one. Having a change over switch, or a patch point may be a better solution.

 

Mac

[TimmyP1955]

You can buy a transformer combiner from a number of manufacturers, or you can make a passive combiner from parts from RadioSpares: http://www.rane.com/note109.html

[mackerr]

You can buy a transformer combiner from a number of manufacturers, or you can make a passive combiner from parts from RadioSpares: http://www.rane.com/note109.html

While that is fine for combining 2 signals so that the output stages of the 2 devices don't interact and short each other out, in the OP's case it also leaves the open line as an antenna when it is not being used. With the 2 lines just wired together the source at the far end will provide termination to the whole circuit.

 

Mac

[jodat2]

I'm guessing its a dynamic mic. Correct me if I'm wrong but if the mic requires phantom power, this may cause a problem on some consoles when using two seperate channels for the same mic.

[david.elsbury]

What are you on about? The OP is talking about combining from 2 sockets to one mic input on the mixer.

 

With regards to what you posted, yes in theory there might be a problem but if you go into 2 channels on the same console then it's unlikely to cause problems. However if you were concerned then you could lift pin 1 on the second channel (the one not supplying Phantom) and there would be no way that phantom power could be sent via that channel to the mic.