wireless audio

[Richard Crowley]

Originally Posted by Pete Cofrancesco

I figured things out. I ran a test and discovered when a stereo signal is plugged into the transmitter, it discards the right channel and sends only the left.

Yes, that is because your unidentified "Y-thing" is apparently a "stereo breakout" adapter which assumes Left=Tip and Right=Ring. But since we have established that the TRS input to your transmitter is monaural, it is no surprise that it is getting only the Left side of the stereo signal. So you aren't really combining L+R, you are simply connecting Left to the transmitter and discarding the Right channel.

[Pete Cofrancesco]

Originally Posted by Richard Crowley

Yes, that is because your unidentified "Y-thing" is apparently a "stereo breakout" adapter which assumes Left=Tip and Right=Ring. But since we have established that the TRS input to your transmitter is monaural, it is no surprise that it is getting only the Left side of the stereo signal. So you aren't really combining L+R, you are simply connecting Left to the transmitter and discarding the Right channel.

My confusion was that I knew the wireless transmitter sends a mono signal and the guy I'm covering the job for is insisting I feed it a stereo signal with a splitter cable.

He's used this method for a long time and never realized he's just getting the left. I don't think I could convince him otherwise and if he's been happy with the results I'm going to leave it alone.

[Richard Crowley]

It seems quite possible that he was indeed combining Left and Right into Mono using a proper "Y-adapter". However, you appear to be using a "stereo break-out" adapter which physically looks identical to a "Y". But because of the way the input connector of the transmitter is wired, it is getting only one channel.

You could be right. But without much better detail about exactly what he was using and what you are using, there isn't enough information available here to conclude either way.

[Pete Cofrancesco]

The Y cable is something I found in my supply box. I'm not sure what I could tell you more about it. I can try to get a hold of his setup today but I have used it in the past and I believe its just a bunch adapters cobbled together.

Btw, would I need to convert an unbalanced input if my transmitter input is unbalanced?

[Rick Reineke]

"Btw, would I need to convert an unbalanced input if my transmitter input is unbalanced?"
- Not if it's unbalanced already.
OTOH, balanced to unbalanced ....or... unbalanced to balanced would need 'custom' wiring. Normally an XLR's pins 1 and 3 are tied together (or the ring and sleeve terminals on a 1/4" TRS).

[Pete Cofrancesco]

Looks like I got mixed up along the way, so I don't need it balanced.

So the two issues I need to address are:
1. To be able to attenuate if I'm receiving a speaker line level.
Jay recommend the Rolls DB25
2. To mix stereo into mono. Although I'm not sure there would be a big difference.
So is there a device that does both theses things otherwise you get a mess of stuff. I have Sound Device 302 field mixer but I'm not sure if its the right tool for the job.

[John Nantz]

Originally Posted by Pete Cofrancesco

My confusion was that I knew the wireless transmitter sends a mono signal and the guy I'm covering the job for is insisting I feed it a stereo signal with a splitter cable.

He's used this method for a long time and never realized he's just getting the left. I don't think I could convince him otherwise and if he's been happy with the results I'm going to leave it alone.

Pete - it gives me pain to read this.

Idea: If he isn’t one that’s easy to convince, assuming time and distance isn’t a problem, what about if you meet with him and either he gives you a connector(s) to use or he blesses something that you have?

And code it/them with tape.

I’m sorta like Steven a few posts up. Filled in to do a stage performance, did a trial shoot during rehearsal, the stage was too dark and there was a lot of grain. Showed the other videograper what it was like, told to go ahead and do it, put a lot of time into it, then was told it wasn’t good enough. This was several years ago and I haven’t forgotten about it.

Having everybody happy feels good. Being a fall guy is no fun.

[Pete Cofrancesco]

He no longer lives locally that's why I'm covering it. I also don't think it's a big deal discarding a stereo channel especially in this scenario. How many people watching a dance recital on their tv could tell the difference?

[John Nantz]

Yea, putting it that way, you’re probably right.

But remember another saying: “No good deed goes unpunished!"

[Jay Massengill]

I recommended using the Rolls DB25b for several reasons.

First, it has a wide range of variable attenuation from -20db down to infinite attenuation, and we really don't know what level the RCA connectors you have access to will carry other than it's some type of line level.
Usually that's -10db but as mentioned some mixers output much hotter than that on the RCA connectors.

We know the Sony beltpack transmitter can be set to Line level input, but I haven't read any specs on exactly how hot it can accept.

Second, the correct Sony cable (EC-1.5BX) for inputting Line level signals into the beltpack transmitter has a female XLR connector. Even though the connection into the transmitter is unbalanced, the DB25b would be an easy way to make this connection and have some variable attenuation if needed.

However, if you really want to combine both RCA signals, the DB24 you mentioned would do that using the Mono/Stereo switch on the back of the unit. It also has attenuation controls.

You would just need a cable with female XLR to the correctly wired mini TRS male end to go into the transmitter properly.

How much time do you have before this event? Can he describe exactly the cable he used before?

[Paul R Johnson]

This is just a bit silly, and making it far more complicated than it needs to be. Richard said it way back - you can parallel up a stereo output to make it mono. Ideally it should be done properly, but finding equipment that is bothered by this is rare. If you can solder, do it properly - join the two RCA connectors from left and right sources to produce a single unbalanced signal. If you can't solder, then you have to sacrifice a made up cable, and use block connectors with screw terminals (not sure of the US term) to route both to the same input.

The TRS connector on radio packs does get used to supply the +Volts on a separate pin, but some, like Sennheiser have the mic and the line level on the tip and ring. A guitarist buys the guitar lead that is connected to the line input, but the mics use the other input. The connector type denotes absolutely nothing!

If the prospect of recording just the left, or right worries you - and I guess that for most music, people won't notice - but if it was say a 70s big band recording, you'd be in trouble, or an early Beatles recording - because they panned hard left and right. So Glenn Miller style do-wop do-wop sax and trombones would mean it would either be wop or do, not both.

For dance shows, I always try to take with me their CDs, because then I always have the get out of jail possibility of replacing the room sound with the CD for emergencies.

Why not just make up an adaptor cable for stereo to Sony, and keep it in the toolbox?

[Jay Massengill]

I did find in Sony materials the beltpack transmitter input when set to Line level can take +4dBu.

I figured out a way to mock up this planned connection from two RCA's to the Sony beltpack transmitter using just two off-the-shelf cables and will test it later today if I have time.

[Pete Cofrancesco]

Thanks Jay take your time the job is a month away.

I can solder but I'll wait for Jay's off the shelf solution.

I noticed that even though the body pack's menu has an attenuate setting it can't be used when set to line.

One other note about songs that have a strong channel change. They would still be heard in the camera's other channel that is recording the ambient via shotgun mic.

Yesterday we couldn't find his setup but like I said I've used it previously and it was a series of off the shelf cable adapters connected to an ancient bodypack, so I doubt it mixed it down to a mono signal.

After reading Jay's post I realized I have the necessary equipment to pull off a single channel solution as follows:
Body pack > trs to xlr cable > xlr attenuater > xlr to rca cable

[Paul R Johnson]

That does the 'mono-ing' too?

Scrap the pile of adaptors, get the iron out and in ten minutes, job done and 100% reliable. No point over complicating this. Keep it as simple as possible.

[Rick Reineke]

I concur with Paul. Your asking for trouble with a bunch of adapters daisy-chained together, especially the low cost "Made in China" variety w/ molded on connectors. They break just by looking at them.