Mono output or Main outputs L/R

[jose99a]

Heres the setup: Source(cd has mono option), to mixer(Ashly LX308), to crossover(BBE DS24), to amp(QSC). I've always used the mono out from mixer to the xover's input A to xover's top(output 2) and sub(output 1) outs for 1 amp operation.
The other day I ran 1 amp for tops, 1 amp for subs (the correct way) using the mixers main outs L/R channels to xovers A/B inputs. After that day I set up like I always do 1 amp (top/sub), I forgot and and left the mixers main out R channel connected to the xovers B input.
The question is why can the volume be changed by the mixers "stereo output dial" but I'm using the mono output which has a dedicated mono output dial?

Also on a different topic is this true: "if you sum the low frequencies of stereo recordings into mono, low-frequency interchannel phase differences partially or completely cancel each other, reducing or eliminating low-frequency output levels! Try jamming a stereo bass signal through mono and you lose a lot of hall ambience as well as bass level."
And if this is true should I just run L/R instead of summing the signal to mono?

Thanks " sorry for the long post"

[jose99a]

I forgot this is what Ashly's manual says:

5.6 Stereo Output Level
This is the main master gain which sets the operating
level for the entire mixer. This control does not
effect the mono output level.

5.8 Mono Level
This is the master gain control for the mono output,
which is the combined signal of the left and right
outputs. It has no effect on the stereo output.

Do I need to adjust the "Stereo Output Level" to get a better signal to the mono channel?

[Grant Bunter]

I forgot this is what Ashly's manual says:

5.6 Stereo Output Level
This is the main master gain which sets the operating
level for the entire mixer. This control does not
effect the mono output level.

5.8 Mono Level
This is the master gain control for the mono output,
which is the combined signal of the left and right
outputs. It has no effect on the stereo output.

Do I need to adjust the "Stereo Output Level" to get a better signal to the mono channel?

As per your quotes from the manual, the stereo output master does not affect mono output level and neither does the mono output level affect stereo output level.
At least that's how I read it.
So adjusting the stereo output level will not get a better signal to the mono output channel.

The question is why can the volume be changed by the mixers "stereo output dial" but I'm using the mono output which has a dedicated mono output dial?

Each output can change the volume. So if you normally run just mono, but the right channel from the stereo output was still into the BBE and you turn up the stereo output volume you will increase the volume, but this doesn't mean the mono output level has increased.
If you press the stereo output mute button, the increased volume should stop.

if you sum the low frequencies of stereo recordings into mono, low-frequency interchannel phase differences partially or completely cancel each other, reducing or eliminating low-frequency output levels! Try jamming a stereo bass signal through mono and you lose a lot of hall ambience as well as bass level.

I think that statement is gibberish. The only way you could get partial or complete cancellation by summing is if, for some crazy reason, at mixdown, the left and right signals or parts of those signals, were made out of phase to each other, so that when summed, the 2 channels cancelled each other out.

Also, you're not summing the signal. As far as I understand it, the mixer is summing the signal to mono. From the manual: "Ultra low-noise summing amplifiers combine the channel signals for the main outputs."

Source(cd has mono option)

Just check in your CD manual that the mono option is not simply one channel's output eg left or right.
I would actually use channel 8 with it's stereo input for your CD player, but still run output in mono.

Hope this helps...

[jose99a]

Ok, thanks I understand, but there is one thing thats driving me crazy, when I turn the dial up on the stereo out it adds bass volume only to the the sub channel not the top channel. I've switched the L/R from the mixer to the B input on the xover and there is no added volume to the top channel. The bass hits harder and a more full sound. Why would the stereo out dial act like a bass attenuator?

[Grant Bunter]

Tricky one for sure!

I guess, so you don't have to worry about it, just don't run it in mono with the right channel also plugged in.

It's likely you're increasing the gain significantly on the sub output somehow when you turn up the stereo output dial.

This will change your crossover point, moving it higher...

edit: I did read the manual for the DS24 it made no mention of summing inputs for LF output, but doesn't mean that isn't the case.

[jose99a]

I bought the mixer used, could the previous owner changed something internally?
Can anyone out there duplicate the problem I"m having?
The thing thats getting at me is why the bass has a fuller sound?
Do I need to redo the xover settings "gain, limiting" with the stereo out engaged as its affecting the mono out?

[Grant Bunter]

I bought the mixer used, could the previous owner changed something internally?
Can anyone out there duplicate the problem I"m having?
The thing thats getting at me is why the bass has a fuller sound?
Do I need to redo the xover settings "gain, limiting" with the stereo out engaged as its affecting the mono out?

Run mono only or stereo only, just pick one. If you're running mono only, then only use one lead from the mixer to the BBE, remove the other lead.

I've tried to explain, stereo out doesn't affect mono out level (and vice versa), but using both at the same time will increase gain level, and perhaps that's where you're getting your fuller bass.

I highly doubt anyone has changed anything in the mixer...

[Bruce Weldy]

Ok, thanks I understand, but there is one thing thats driving me crazy, when I turn the dial up on the stereo out it adds bass volume only to the the sub channel not the top channel. I've switched the L/R from the mixer to the B input on the xover and there is no added volume to the top channel. The bass hits harder and a more full sound. Why would the stereo out dial act like a bass attenuator?

If the crossover's L and R are summed for the sub output (which I bet they are as that is normal operation), then when you turn up the Stereo knob on the mixer you are adding the Stereo Right content to the crossover.

Since you are not using the Stereo Right output of the crossover, you don't get any increase in the tops - however, the sub content from Stereo Right is being summed along with the mono output of the mixer through Stereo Left on the crossover, essentially doubling the low end signal.

By turning up the stereo out put of the board you are adding only bass content since you aren't using the A side at all, and the B side output isn't being used. All that is left is the low end content on the B side which is getting added to the mono input - thus acting as a bass attenuator.

No magic here - you just hooked it up wrong. Everything is working just the way it should.

[jose99a]

Problem/Confusion - Answered/Solved!!! "more of a confusion"
Thank You for your patience, finally I get it.
Xovers input A goes to outs 1/2, input B goes to outs 3/4.
" A&B lows summed to outs 1/3"
Mixer mono out to xover input a - out to 1/2 to amps. When I left the cable to xover B input from mixers stereo outs, the summed signal was going to output 1 sub but since I wasnt using the xovers output 4 top to my amp there is no way sound would come out. Turning up the dial on stereo outs I was turning up the summed low signal to output 1.
Thank you again, sometimes the answer is right there in front of you.

[Tom Smit]