Gain Structure with SL16

W

Wali Raffiqi

Freshman
Jan 19, 2011
26
0
0
South Riding, Va
Hey folks,

Just received my SL16 and a 260. Unfortunately I haven't had any time to mess with them, so I will have to do everything when I get to the venue later today (typing this while sitting in class :p).

I have had a couple of minutes here and there to try to figure out how and what to use to set the gain structure. I tried to use a 1/4" to xlr cable straight from the iPhone to the board, which works fine in the first couple of minutes, then something happens to the signal. When I play music, it gets this effects type sound to it, and the vocals are almost faint, and can mostly hear guitars. The signal drops by about 10db as well. I have switched adapters, cables, headphones, with no success. (I'm listening to the signal through the solo bus and headphones btw)

Maybe I'm doing something wrong. What is the best way to feed signal to the SL for gain structure? Should I use a DI in between the two devices? I didn't have this issue with the MG32.
 
Re: Gain Structure with SL16

Wali Raffiqi said:
I tried to use a 1/4" to xlr cable straight from the iPhone to the board, which works fine in the first couple of minutes, then something happens to the signal. When I play music, it gets this effects type sound to it, and the vocals are almost faint, and can mostly hear guitars. The signal drops by about 10db as well. I have switched adapters, cables, headphones, with no success.
Click to expand...

Are you using a cable like this:
XVM105M.sized.jpg


or like this:
41S%2BR55QGLL._SL500_SS120_.jpg


???
 
Re: Gain Structure with SL16

It's like the first one but a 1/4" instead of 3.5mm. I use a 1/4" to 3.5 to connect to the iPhone.

Also, I will be using pink noise for the signal, of course. I'm just curious and worried and want to make sure it doesn't affect anything. The gain reduction is the main thing I'm concerned about.
 
Re: Gain Structure with SL16

Wali Raffiqi said:
It's like the first one but a 1/4" instead of 3.5mm. I use a 1/4" to 3.5 to connect to the iPhone.

Also, I will be using pink noise for the signal, of course. I'm just curious and worried and want to make sure it doesn't affect anything. The gain reduction is the main thing I'm concerned about.
Click to expand...

You are shorting the left and right together which is giving you cancelations since the source material is in stereo. You need a cable more like the second one.
 
Re: Gain Structure with SL16

So if I'm sending pink noise through the generator app in the iPhone, should I not worry about that? Or would I still need a splitter to split that signal as well?
 
Re: Gain Structure with SL16

Wali Raffiqi said:
So if I'm sending pink noise through the generator app in the iPhone, should I not worry about that? Or would I still need a splitter to split that signal as well?
Click to expand...

You should measure/EQ only 1 side of the PA at a time anyway. Use a stereo 2 trk input for your intermission music, if the Presonus has one.

You should go to Rat Shack and get 2 ea. TRS 3.5mm (1/8") to double 1/4" phone plugs. Cut off the 1/4" plugs from one of the cables and replace them with male XLRs. Wire the "-" lead to pin 3, and the "+" to pin 2 for each lead. Do NOT connect pin 1 to anything. This will keep you from killing your playback device with phantom power. Keep the other cord for use with DIs or desks that have 1/4" inputs.
 
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Re: Gain Structure with SL16

Thanks for the tip Tim. I will look into that for next gig, and redoing my structure, but I have no time for today to get everything ready.

It does have a 2TR input, but for some reason it does not show anything in the level meter as far as input level. It only lights up if I'm using the pre-amps.

I will get a splitter tomorrow. I will have to play it safe today and go with what I have I guess.
 
Re: Gain Structure with SL16

Wali Raffiqi said:
I will get a splitter tomorrow...
Click to expand...
Actually, Wali, the cable you want is not a splitter. A splitter (or wye/"y" cable) would take the same signal and send it to both of the other connectors. The cable you want will send one signal to one connector and another (potentially, but necessarily different) signal to the other connector.

A lot of the time, 1/4" TRS connectors are used for mono, balanced signal transfer. In your case, you want to use it for stereo, unbalanced signals, and require a different wiring scheme. You want to split the stereo signal to 2 mono channels (or, if you have a stereo channel available, use that instead).

Personally, I think you should just buy a Whirlwind PCDI (or similar) and have that available for use in the future should you or someone else need it. I use mine all the time and it can be very helpful for troubleshooting because of the transformer isolation it provides.
 
Re: Gain Structure with SL16

Just as a little aside, the sound file of beethoven's 5th that comes packaged as a sample in windows is great for checking laptops as a source. No matter whose laptop they bring you for the presentation, it is almost always there, it has enough stereo content to check both channels, and hopefully we all know what it should sound like.
 
Re: Gain Structure with SL16

Btw tonight was the first time I used the SL, and unless I'm doing something wrong, I really don't like the input to output ratio. At about -10 on the input meter, it was outputting above zero and toying with +10 on the main meters. Fader at unity. Doesn't really give me much headroom. Any help will be appreciated.
 
Re: Gain Structure with SL16

Wali Raffiqi said:
Btw tonight was the first time I used the SL, and unless I'm doing something wrong, I really don't like the input to output ratio. At about -10 on the input meter, it was outputting above zero and toying with +10 on the main meters. Fader at unity. Doesn't really give me much headroom. Any help will be appreciated.
Click to expand...

How loud was it? IOW, what was the audible difference between what you've used/done before and the SL?
 
Re: Gain Structure with SL16

The volume was perfect where I wanted it, but if I wanted to bring anything over the mix just a bit, it would be at +10. I used a MG32 before this and I'd get this volume with it not even hitting 0. I think it has something to do with my gain structure and DR260 setting as well. The 260 is pretty confusing coming from a DRPA. Haha.

Also I'm using a pair of QRx-212s powered by an XTI4000. I feel like it should be much louder than that though.
 
Re: Gain Structure with SL16

Wali....

Are you sure the mains output knobbie on the rear panel is turned up all the way?
 

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Re: Gain Structure with SL16

If you're having to run the board that hot to get enough volume out of your system, I'd say look downstream a bit and see if you have a bottleneck in the DSP unit or the amps.
 
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