Connecting active sub to my Alto PBM8.250 MK II mixer

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
First of all, hello to everyone reading this!

OK, now I will try my best to make sense:

I have the Alto PBM8.250 MK II powered mixer running two passive Wharfedales and I've recently obtained an active full range speaker for use as a stage monitor, and an active subwoofer.

Now, the problem I'm having is this: I only have the following outputs for active speakers:
The Monitor output;
2X Main outputs (left and right);
AUX2 Out (problem with using this output, I can no longer use onboard effects)

The next part of the problem: the two passive speakers sounds best if I boost the low levels with the Parametric EQ, but this boost also have an effect on all the mentioned outputs, and that makes the sub sounds too boomy. I can't adjust frequency on the sub.

Now, the Main and Monitor channels does have separate Graphic EQ's, but I've heard that it is inadvisable to boost the low levels on my main speakers with the Graphic EQ.
Also, this will mean that I would have to put the sub and the monitor on the same channel, which would not be ideal, because if the guy on stage asks me to change monitor levels it also affects the sub.

AUX2 does have it's own level controls, but I can't use this channel for a speaker because I then loose onboard effects like reverb.

The two Main outputs are influenced by all Main controls, so connecting the sub there will bring back the 'boomy' problems.

Am I just screwed with this mixer, or am I being stupid somewhere?
 
what sub and fullrange are we talking about, make, model , etc.
i would use the "fullrange" on "monitor" for exactly that "cueing" or "foldback"
you could use the "tape out" RCA's i can't say for sure whether the are pre or post the graphic, but should provide the sub with a signal(if they're pre graphic your golden!)
 
The whole point of adding a subwoofer to a PA system is to generate more/better bass overall but also to take the responsibility of low bass generation away from the main speakers, this effectively turns your speaker system into a 3-way and it should get louder and stay cleaner sounding as well. What model is your powered sub? If it has high pass outputs you want to feed those back to the mixer for the mains.

My suggestion would be to connect one or both main line outputs(front panel) directly to the sub and then connect the high pass or line outputs from the sub back to the stereo return on the mixer. Main speakers are connected to the amplified connectors at the rear of the mixer as usual, monitor speaker is connected to the front panel monitor output, use the Main graphic EQ for all main speaker tone adjustments, use Mons graphic EQ for all tone adjustments for the monitor speaker. Channel strip EQ is to contour instrument so they mix better not to make them sound better. Clear? Probably not but if you have more questions fire away.
 
Last edited:
Thank you turk 182 and conanski!

That flickering candle in my head is finally slooowly turning into a bright, stable, light...

The reason why I said the passives sound 'better' when 'boosting' the lower levels is because all I ever really did was play music from my computer at casual events (total noob here). Of course there was the vocal mic for speeches and so forth. Only did about 4 small events where someone was singing and playing an instrument. At none of these events I had a sub or floor monitor...Only got them recently...So about live mixing I still have like EVERYTHING to learn.

Anyhow, today I've spent some (according to me) quality time with the equipment. I've left everything on the mixer flat. No tuning. Only tuning I did was with the level of the subwoofer itself to achieve just the right balance between sub and main speakers... Then played a song from my phone...And that was the best clarity I've ever heard from this system!

So, conanski, by pointing out to me that I have no idea how to use the channel strip EQ, and also the part where the sub should take the low bass responsibility away from the main speakers completely, I believe my problem are solved.

I'm still not sure whether I'm still learning or just stupid though...

Oh yes, and about the brand/model: it's the product of a local company, which also only distribute locally.
The specs on the sub are pretty basic: 1X XLR input; 2X RCA input (L/R); 1X XLR Thru/HPF line out. And then just the level control and polarity switch.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.