While mixing ,I used an aux send for anacoustic guitar to a good anaolg eq and patched back through one of the regular channel inputs . When I did this the vocal (the guitarist was also singing) got that slightly tubular sound . I reversed the phase and the vocal improved but the guitar lost something . When I removed the eq processor and stayed digital it was fine . Anybody have any ideas? Could this be a latency problem ? If it is , does anyone know how much I should delay the vocal ? Or could it have something to do with the unbalenced aux send going into a balanced processor(I'm coming out of the processor on an unbalanced jack to and not using any special cords to address the balanced unbalanced issue).Thanks for any help

It's the direct send signal mixed in with the return signal and there out of time. Eaither unassign the send to the l/r mix or use a delay setting between the 2 so it can be more in phase.

As Jeremy said, it's the mix that's giving you the problem. You're experiencing the A/D and D/A delays going out and into the board.

You can't "advance" the returned signal, so what you do is delay every other track in the mix. Put up a couple of tracks and the late return, and determine the best delay value to use on the straight tracks. Set this delay on all other tracks too, and save the scene.

Now all your straight tracks will be delayed by the same amount as the out-FX-in signal, and there won't be any phase problem.

Oh, and you'll have to make sure the acoustic guitar isn't routed directly to LR, but simply goes out an Aux, gets EQ'd, and comes back a spare channel. This keeps the original and the delayed copies from both being in the mix.

If you have leakage in the acoustic guitar signal, which is likely, that's why you have to delay everything else. Otherwise that 20% of the vocal in the guitar mike will sound funny.

Is this a way to get around the problem of inserting on playback without having the insert card?

Thanks for the info . I thought it might be that . What about going from the unbalanced sends into balanced inputs on a processor and out unbalanced ? It seems to sound fine , but me not really knowing what's happening with pin 2 and 3 on the output side of the processor makes me wonder .
Will , this is a way to add outboard eq or other processing as kind of an insert .Like Rick and Jeremy said just make sure you don't assign the original signal to be processed to LR output . If you want to send the newly processed signal to another send(like for reverb or dealy) you have to return it to one of the anolog inputs . The bummer with that is you have to go thru the DA7s preamps before the AD converter . I don't want to knock the onboard preamps but I almost sold my board beacause I did not like the sound I was getting .I have a couple of Avalon 737s and they sounded better going straight to ADAT then going through the DA7 preamps . When I put the Avalons into the aux returns on the board the sound really improved ,definately an improvment over the ADATs ADs. I'm going to buy an ADDA card soon unless I can find a good 8 channel
ADDA solution that wont break the bank. Speaking of which , if anyone's got one they want to sell let me know (ADDA card or other outboard converters).

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As for balanced and unbalanced, here are some general guidelines. I assume pin 2 is hot, pin 3 is cold, and pin 1 is ground on a balanced XLR. For balanced TRS, tip is hot, ring is cold, and sleeve is ground.

Unbal line -> bal input
You can feed unbalanced into balanced, but it's good practice to ground pin 3 (cold). This is done automatically when you plug an unbal 1/4" TS cable into a bal TRS input jack. Leaving the cold ungrounded will not cause damage to the input, though you might get a little noise. If it sounds OK, there's no problem. The resulting signal level will always be 6dB less than if you had fed in a balanced signal.

Bal out -> unbal line
This is the one to be careful with. The balanced output usually has two line drivers (or a transformer), driving the hot and cold lines 180 degrees out of phase.

First, let's consider an unbalanced XLR cable with pin 3 (cold) left open. This will work for all systems EXCEPT transformer-balanced. For transformer outputs, you MUST ground pin 3. Failing to do so will result in weak, possibly distorted sound (but no damage). For solid-state outputs, however, you DO want to leave pin 3 floating, rather than short its signal to ground. Shorting pin 3 to ground on a solid-state output *usually* will not cause damage to the output, but it isn't recommended.

Plugging in a TS plug to a balanced TRS output will automatically short cold (ring) to ground. The above rules apply about shorting cold to ground.

You might consider making a few balanced-unbalanced conversion cables in various combinations, BUT remember to carefully mark them so you don't use them in the wrong application.

One neat application of bal out->unbal line is to get a phase (polarity) inversion. Just take the cold output instead of the hot, and your resulting signal is phase-flipped. Here again, you can make a special patch cable to do this.

I have several such patches: XLRM-XLRM, XLRF-XLRF, XLR phase flip, XLRM-TRS balanced, XLRM-TRS unbalanced cold.