Mixers/Consoles Why am I losing an audio channel?

[Les]

So I'm doing sound for my cousin's wedding next weekend and I went and bought some adapters from Banjo Center so I can run my iPhone through the mixer for background music during the reception, and I'm having trouble with the stereo separation on the input side of things.

Essentially what I have is a TRS (female) to 3.5mm (male) Stereo adapter coming from the iPhone to a 5' TRS (male) to XLR (male) balanced cable which plugs in to my mixer. Problem is, I'm only hearing "one side" of the recording. I had the same problem adapting from 1/8 to 1/4 input, but I thought going XLR would fix the problem. I'm just going in to a channel on the mixer (Mackie ProFX 12). I also thought that TRS as opposed to TS would address this issue but maybe I was wrong. Do I need to go to TS instead?

Weird thing is that a 1/8" TRS to RCA going to the TAPE input works fine, but I need to run more than one device.

I'm sure I'm missing something simple, but what?

Here's what I'm attempting to use:

 

[DaveySimps]

You are missing an entire channel since you are not summing the stereo signal anywhere. The TRS is just giving you the addition of the ground wire in the XLR adapter. You need an adapter that gives you 2 XLRM's or a DI (or other device) that will sum the signal properly to mono.

http://www.hosatech.com/media/document/CYX400M.pdf

http://www.hosatech.com/product/0/CYX-402M/_/Stereo_Breakout,_3.5_mm_TRS_to_Dual_XLR3M,_2_m

http://artproaudio.com/artcessories/di_boxes/product/av_direct/

~Dave

 

[dmx]

Les,
I have always used a 3.5mm to dual RCA adapter with RCA to 1/4" adapters. Sweetwater has this cable that won't require adapters:
http://www.sweetwater.com/store/det...g&matchtype=&gclid=CM6UrZ6Q8LoCFQbNOgodChgAGQ

Retain stereo by panning ch1 left and ch2 right.
-Matt

 

[techieman33]

I'm a lighting guy but I'm pretty sure you'll need to use 2 channels in the desk to get stereo sound. Since your only going into one channel, your only getting one channel. So you'll need use an adapter to split it into 2 channels. I know our sound guy uses a 1/8" to RCA then goes into a DI then into the console and only uses one channel that way.

 

[Les]

Wow, thanks for the quick responses, guys!

For the time being, I'll probably just split to two XLR's or 1/4 since I don't really need the desk channels, but I do need to pick up a DI one of these days.

I was under the impression that I would just get the same sound out of both speakers (which would be fine - no need for stereo separation here), but it looks like I've got a bit to learn yet.

 

[MNicolai]

For the time being, I'll probably just split to two XLR's or 1/4 since I don't really need the desk channels, but I do need to pick up a DI one of these days.

DI's are the safest approach. Line inputs via 1/4" are acceptable or Tape inputs via RCA, but stay far away from any XLR to 1/8" cables. Such adapters enable you to inadvertently send +48V phantom power into your iPhone's headphone port.

It's a guaranteed way to blow up the headphone port, although the last time someone did it that I know, they took it to Apple, said, "I don't know what happened --- it just stopped working all of the sudden."

Apple said, "Oh, interesting. This is actually a known issue, so if you don't mind, we'd be happy to give you a new iPod to replace it."

I wouldn't be deliberately risky and tempt fate hoping Apple will give you a new iPhone though. Stay clear of XLR to 1/8" adapters.

 

[Les]

DI's are the safest approach. Line inputs via 1/4" are acceptable or Tape inputs via RCA, but stay far away from any XLR to 1/8" cables. Such adapters enable you to inadvertently send +48V phantom power into your iPhone's headphone port.

It's a guaranteed way to blow up the headphone port, although the last time someone did it that I know, they took it to Apple, said, "I don't know what happened --- it just stopped working all of the sudden."

Apple said, "Oh, interesting. This is actually a known issue, so if you don't mind, we'd be happy to give you a new iPod to replace it."

I wouldn't be deliberately risky and tempt fate hoping Apple will give you a new iPhone though. Stay clear of XLR to 1/8" adapters.

...If only Apple knew the occupations/hobbies of those who had these "known issues".

Thanks for the tip. I do need a DI for my keyboard anyway, so I'll just pick one up in lieu of buying more cheap adapters. Good thing I didn't hit "that button".

This is what happens when a lighting/pyro guy does sound... My RCF Art 312a's sound good though!

 

[MNicolai]

DI's are good to have, but on your Mackie, an 1/8" TRS to dual 1/4" TS adapter should be fine, connected to two line input connections. The 1/4" line inputs do not receive +48V. This would be cheaper than using DI's, and you'd need this cable anyway to get into DI's.

Which DI you'd get if you wanted to would be up to you. Some DI's (such as this) are native for stereo sources and provide you XLR Left Channel and XLR Right Channel outputs. It's a slick solution but most often I just use two $35 DI's with mono 1/4" inputs. Together, they equal stereo.

As a general rule, if you're standing next to the mixer with your iPhone, going the 1/8" TRS to dual 1/4" TS approach is fine. If someone had a stereo source on stage like a laptop, you'd want to use DI's to transmit the signals back to the console as XLR's. The signal from the iPhone is "Unbalanced", which doesn't like to be transmitted over cable long distances like from the stage to FOH. DI's convert those to "Balanced" signals that can be transmitted over long distances without signal degradation.

Worth noting is if you used a laptop instead of your iPhone, you could play 2 channels of stereo into your mixer via USB. No DI's, generic cable, doesn't cut into your available channel count. Unfortunately on that mixer it doesn't give you EQ control of USB, but you could EQ through the media player on your laptop.

Given your mixer, t'were it me, I'd do the 1/8" TRS to dual 1/4", and connect to the Line In 11 and Line In 12 jacks on your 11/12 stereo fader. This keeps you safe from the +48V while still giving you full EQ controls and a physical fader.

If you have an 1/8" to XLR cable, just put some red tape on it as a bread crumb trail to yourself to use it wisely and only after exhausting other options available to you. It's not an entirely useless cable, but its applications require a more judicious analysis of the potential repercussions should you use it.