Rock/Pop PA - adding aux sub, crossovers, going stereo! HELP!

[neophool]

BACKGROUND AND CURRENT SET-UP

 

4-person Rock/Pop band (DMB, Coldplay, The Fray style) playing lots of College shows (from small coffee-house style gigs to big outdoor end-of-the-semester campus events) also of course play the obligitory bar and medium sized music venue.

 

For the larger gigs usually a sound company provides, but for some large shows and most of the smaller contracts its our PA.

 

Our PA (as it is now)

 

Mains: 2 QSC HPR152i powered speakers. 500w 15" 2-way.

http://www.qscaudio.com/products/speakers/hpr/hpr152i.htm

 

Sub: 1 QSC HPR181i powered subwoofer. 700w 18"

http://www.qscaudio.com/products/speakers/hpr/hpr181i.htm

 

Monitors: 2 QSC HPR122i powered multi-purpose speakers. 400w+100W 12"

http://www.qscaudio.com/products/speakers/hpr/hpr122i.htm

 

Mixer: Allen and Heath 16:2 channel mixwiz v.3 i think.

http://www.allen-heath.co.uk/US/wz3162.asp

 

in our rack is 2 channels of behringer (ugh) 31band EQ (1 for mains, 1 for monitors now), and 2 channels of DBX compression (not being used.....)

 

How we run it

 

Sub is Aux fed pre-fader (post fader we couldn't get it kickin' enough for some reason) straight to the sub. main outputs from the Mixer are sent to the Mains. that's it. no crossover.....

 

and that's it.

 

 

WHAT WE WANT TO FIX/ADD

 

1) Run PA in Stereo. i've surmised that we'll need at least 1 more channel of EQ to do this.

 

2) Get a damn Crossover. I can't believe we don't have one, its kinda embarassing. Suggestions? we are running an Aux Fed Sub remember, AND want to run the mains in Stereo. Does this mean we need at least a 3-way Stereo crossover? is that enough to route the signals correctly in stereo?

 

3) Clean up the low end. I'm sure that getting a crossover will help this problem, as will convincing both guitarists to eq the bass down on their axes. sometimes its just a giant low ringing mess lol.

 

4) Phatten up the bass/kick. its kinda weak. we never get that thump in your chest - its just loud. it's kinda low, but not thumpin'. My bass just sounds LOUD, not thumping or smooth. Our kick sounds alright, but not anything like we want it.

 

sorry for the long post but we need some help!!! haha thanks in advance.

[dboomer]

The crossovers are built into the speaker systems you have. You shouldn't need any others for normal use.

 

Aux fed subs will help you to clean up the low end.

[neophool]

 

The crossovers are built into the speaker systems you have. You shouldn't need any others for normal use. Aux fed subs will help you to clean up the low end.

 

 

yeah i noticed that, only thing is when we cut the lows on the Mains (the little low-cut corssover switch ont he backs), it sounds terrible, like its cutting a ton of mids out too. we've left the mains on full range.

 

nice to know tho if we can fix that we won't need a crossover. even running stereo we wouldn't need an external crossover? thanks for the reply!

[agedhorse]

Another sub might help with the bottom.

 

There is something REALLY wrong if engaging the HPF's (crossover) on the top cabinets cuts out the mids. You sure you are connecting things correctly.

 

Running stereo would require another EQ channel, and another sub. That's all.

[neophool]

 

Another sub might help with the bottom. There is something REALLY wrong if engaging the HPF's (crossover) on the top cabinets cuts out the mids. You sure you are connecting things correctly. Running stereo would require another EQ channel, and another sub. That's all.

 

 

ooo we'd need another sub to be able to run stereo? i thought we could just get away with one for now - we want to get another one, but right now money is too tight.

 

i thought we could run the mains stereo and the sub wouldn't matter

 

 

as for the speakers crossover, i'm pretty sure everything is connected right. i mean its just mono out from the mixer to the speakers.

[jwlussow]

If you want the subs in stereo you need 2. Why stereo? What size rooms do you play? How many people? Stereo works for some set ups but kills others. It has been discussed ad nauseam here but generally stereo only works for a small group that happen to be in the sweet spot between the mains. A little left or right of the sweet spot or a little too far back or too close and all it does is make the audience not hear part of your performance. Somewhere around 90% of the audience might actually think the sound is a little "off" especially if you really do any hard panning. Stereo can work but you really need to think it out.

[modulusman]

What exactly do you hope to achieve by running stereo? As Andy said something is wrong if you are losing mids when the HPFs are being used. Maybe your 31 band EQ is the problem. I would try your system without the EQ and see how it sounds. If you are already using an aux fed sub that should clear up your low-end.

[Dookietwo]

How we run it

 

Sub is Aux fed pre-fader (post fader we couldn't get it kickin' enough for some reason) straight to the sub. main outputs from the Mixer are sent to the Mains. that's it. no crossover.....

 

and that's it.

 

Left and right main out to the tops will give you stereo and yes just get a better quality eq and your set.

You should be able to setup your aux fed subs post fade. Was the master for the aux turned up enough?

You won't need a crossover as the crossovers in the boxes you have work well. I have the same subs.

 

Your not going to get chest slam'in bass drum with just one sub even if you run your tops full range as well. This could even make things worse if the placement is wrong.

 

http://www.prosoundweb.com/article/in_depth_the_aux_fed_subwoofer_technique_explained/

 

Dookietwo

[hemismith]

Excuse my ignorance, but I see high-pass filters on the tops but nothing on the subs. Wouldn't there be some benefit to only passing desired frequencies to the subs?

[Dookietwo]

 

Excuse my ignorance, but I see high-pass filters on the tops but nothing on the subs. Wouldn't there be some benefit to only passing desired frequencies to the subs?

 

 

The subs have a built in crossover. The sub cover 45-100 hz. They also have highpass outs. Which sends 100hz and above out. A pair of full range outs are on them as well. I can see the reason the OP is using full range tops as with just the one sub they are trying to get all the bass they can with the pa that they have. The sub in the center between the two tops might work.

Boosting the bass drum channel at 70/80 hz would give a little more thump. Using an Aux send would keep the aux fed sub devoting all its power just to a few inputs. Maximizing its output. Of course allot depends on the mic and tuning on the bass drum.

 

Dookietwo

[6Imzadi]

Yes, tuning on the bass drum is important, but so is the mic and mic placement.

 

Using aux fed sub is the way to go, look at the output master to be sure that it is turned up. Again, you won't get chest thumping low out of one sub. To get really chest thumping low out of your subs, you may consider 4 of them clustered together in the middle of the stage front. Then you will have the thump you are looking for.

[Shaster]

 

Sub is Aux fed pre-fader (post fader we couldn't get it kickin' enough for some reason) straight to the sub.

 

 

I hope you mean pre fader, but post EQ. If you're pre fader and pre EQ this won't give you much control over the kick, bass and so on. Also, if you're pre fader, wouldn't it also be awkward to turn the kick... up or down in two separate places?

 

I've also run Aux fed subs on the MixWiz, and engaged the aux 6/main fader switch so that I've got an "output" fader to the subs.

 

Check the various Stereo vs. Mono threads that happen every couple of months here - not much reason for "stereo" unless you're a movie theater, IMO. Of course I don't know your specific needs.

[neophool]

thanks for all the replies! very good info.

 

We are running the aux fed sub on a pre aux - we did have the aux master all the way up and it was like the Sub wasn't even on when it was run Post fader.

 

re: pre-EQ - well the EQ on the MixWiz mixing board would be controlling each channel anyways right? so we do try to EQ the kick and bass a little here, and can hear changes, but enver attain what we want. the 31-band Behringer EQs are both after the mixing board (mains and monitors)

 

re: Stereo - interesting, i did have a feeling that running stereo would be troublesome for spacial placement, but didn't realize it was that bad! i thought it would help define instruments better and clean up the mix, but i guess i was wrong lol

 

so the way we have the cables run are like this (if i remember, i don't set it up)

 

mixer -> main mono out to eq channel 1, out to Left Main, out of Left main to Right Main.

 

mixer -> sub aux straight to Sub (no seperetae EQ, only the mixing boards EQ)

 

to turn things "up and down" we just gain it in the check, then to make it louder we just turn that channels aux up or down, we don't mess with the fader since it's pre-fader. i'm assuming we're doing something wrong here.

[Crownman]

My .02

 

If this was my system I'd get another sub. Then a DBX231 and a 4 ch compressor.

 

As others have said there's really no reason to run stereo, especially for cover band situations where you don't know where the crowd will be standing. Mono lets everybody hear everything.

 

I helped some friends set up their system which is pretty much the same, all powered speakers. This is how I hooked it up and had good results.

 

Pan all instruments for the mains to the left.

Mixer L out > dbx231 ch1 > snake > fullrange input L main > full range out to R main.

 

Pan kick & bass to the right.

Mixer R out > dbx231 ch2 > snake > full range input on L sub > full range out to R sub.

 

Engage filters on the mains.

Then use the direct out on the bass ch and run into the channel next to it so you have 2 channels of bass guitar. Pan the 2nd channel to the L. This will allow you to send the mains some of the high end on the bass for some definition when you want it (slap bass & such).

 

Use the 4 ch. comp for 3 vox and the 4th for the kick.

Use the 2 ch comp for the two bass guitar channels.

 

Since you have 2 powered monitors. Run two monitor channels and use the behringer EQ for them.

 

aux 1 out > behr. ch1 > snake > monitor 1

aux 2 out > behr. ch2 > snake > monitor 2

 

I know you want it in stereo but I'll bet monet that with it setup like this you'd be plenty happy with it and it would sound good.

[neophool]

 

My .02 If this was my system I'd get another sub. Then a DBX231 and a 4 ch compressor. As others have said there's really no reason to run stereo, especially for cover band situations where you don't know where the crowd will be standing. Mono lets everybody hear everything. I helped some friends set up their system which is pretty much the same, all powered speakers. This is how I hooked it up and had good results. Pan all instruments for the mains to the left. Mixer L out > dbx231 ch1 > snake > fullrange input L main > full range out to R main. Pan kick & bass to the right. Mixer R out > dbx231 ch2 > snake > full range input on L sub > full range out to R sub. Engage filters on the mains. Then use the direct out on the bass ch and run into the channel next to it so you have 2 channels of bass guitar. Pan the 2nd channel to the L. This will allow you to send the mains some of the high end on the bass for some definition when you want it (slap bass & such). Use the 4 ch. comp for 3 vox and the 4th for the kick. Use the 2 ch comp for the two bass guitar channels. Since you have 2 powered monitors. Run two monitor channels and use the behringer EQ for them. aux 1 out > behr. ch1 > snake > monitor 1 aux 2 out > behr. ch2 > snake > monitor 2 I know you want it in stereo but I'll bet monet that with it setup like this you'd be plenty happy with it and it would sound good.

 

 

so this is just a different way of limiting the signals to the subs? kind of like an aux fed sub system?

[neophool]

Yes, tuning on the bass drum is important, but so is the mic and mic placement. Using aux fed sub is the way to go, look at the output master to be sure that it is turned up. Again, you won't get chest thumping low out of one sub. To get really chest thumping low out of your subs, you may consider 4 of them clustered together in the middle of the stage front. Then you will have the thump you are looking for.

 

the bass drum is tuned well and is a pro DW kit. the mic is a Shure Beta 52a, put right in a tone port in the front.

 

we thought that just 1 18" qsc sub would be alright, but i guess we really do need 2. We do center the Sub whenever we can (sometimes at bar gigs there is no stage, so we put it next to one of the mains' poles.

 

i guess we need to save up for another sub.

[boomerweps]

For all the hype and push to have a seperate EQ on everything, I say pick where you want them for now, mains in stereo or monitors, and let the others run free. Do you have much feedback problems? If so, use the EQ for the monitor mixes (seperate the monitors on seperate aux outs). If the feedback is rare, place the EQ on the TOPS in stereo for speaker sound shaping. I am ASSUMING that since you are running the tops mono, you MAY be using the other EQ channel for two monitors on the same mix.

 

Bottom line, the speakers are better quality than the EQ (not brand bashing B, lotsa good or adaquate Behringer items, analog EQs are NOT considered one of them). My PA system has the monitor EQs pretty much left flat and we have NO feedback. The mains graphic EQ is flat BUT I use a DRPA so the mains are tuned to factory specs by a few parametric filters. And we've used the tops without any EQ several times for simpler setups, NOT using the DRPA. No feedback and they still sound pretty good (Yorkville U15s)

 

Boomerweps

[Crownman]

 

so this is just a different way of limiting the signals to the subs? kind of like an aux fed sub system?

 

 

Exactly, but it let's you keep all the aux's free for FX or more monitor mixes when you need them.

[neophool]

any recommendations on the following ideas?

 

1) A DriveRack PA unit or BBE equivilent type unit.

 

http://pro-audio.musiciansfriend.com/product/reviews?base_pid=183588&page=1&sc=date&so=desc

 

(thought we'd need one of these seeing as they have compression, EQ, crossovers, and a subharmonic synth al in one unit.

 

was wary because of the low price (how can all these effects be as good as DBX's seperate units if the DriveRack is so cheap) and user-friendliness. now it seems like we don't need the crossover.

 

 

2) A DBX Sub harmonic Synth

 

http://pro-audio.musiciansfriend.com/product/dbx-120A-Subharmonic-Synth?sku=183587

 

(with just one sub will it really make a difference? and the freq. response on the QSCs are only down to 45. I HAVE heard these things in action tho, and they really do work well - just not sure if our low end can take advantage/project what this sub harmonic synth will do.

[neophool]

 

For all the hype and push to have a seperate EQ on everything, I say pick where you want them for now, mains in stereo or monitors, and let the others run free. Do you have much feedback problems? If so, use the EQ for the monitor mixes (seperate the monitors on seperate aux outs). If the feedback is rare, place the EQ on the TOPS in stereo for speaker sound shaping. I am ASSUMING that since you are running the tops mono, you MAY be using the other EQ channel for two monitors on the same mix. Bottom line, the speakers are better quality than the EQ (not brand bashing B, lotsa good or adaquate Behringer items, analog EQs are NOT considered one of them). My PA system has the monitor EQs pretty much left flat and we have NO feedback. The mains graphic EQ is flat BUT I use a DRPA so the mains are tuned to factory specs by a few parametric filters. And we've used the tops without any EQ several times for simpler setups, NOT using the DRPA. No feedback and they still sound pretty good (Yorkville U15s) Boomerweps

 

 

yes, exactly. we have 1 channel of the Behringer eq for the tops mono, and the other channel governs the monitor mix (both on same like you guessed, myself (keybass and keyboards) and the drummer both use in-ear systems, the Lead singer/guitar uses both monitors, and the electgric guitar player doesn't use a monitor at all.

 

we hardly ever have feedback problems, only 1 vox mic, and only 1 amp on stage making noise (elec guitar) no bass amp or acoustic guitar amps. stage noise is pretty low to be honest, even tho our drummer is on the loud side. we've cut around 4k and 800k on the mains, and cut the same plus a couple other freq in the monitors and hardly ever fiddle with it.

 

as for stereo, i think i'm going to abandon that idea. UNLESS - running stereo and simply not panning any of the mono instruments (keeping them all dead center) and just hard panning L/R any stereo instruments (stereo keyboards, Hammond organ leslie effect) would not cause "hearing" problems for audience menbers not in the "sweet spot"

 

i can easliy see how getting all creative with panning (matching stage position, etc) would cause problems out front with people not hearing things on the other side.

[neophool]

 

Exactly, but it let's you keep all the aux's free for FX or more monitor mixes when you need them.

 

 

that is a nice suggestion! although we don't have a need for any additional Auxes yet, this is going to come in handy at some point, i assume.

 

all we use on our auxes now are 3 monitor mixes and the Aux Fed Sub - our mixer has 6 auxes, 4 pre.

 

i can't think of what else we'd need more auxes for?

[Crownman]

So right now you're not running any FX? If you do ever you'll want those through aux's.

 

Don't even worry about the DRPA at this point. You don't need the crossover and don't really need the othere stuff either. With only one sub or even if you had 2 the sub synth isn't really going to make any major noticeable difference IMO.

[Kyle Abel]

 

1) A DriveRack PA unit or BBE equivilent type unit. http://pro-audio.musiciansfriend.com/product/reviews?base_pid=183588&page=1&sc=date&so=desc (thought we'd need one of these seeing as they have compression, EQ, crossovers, and a subharmonic synth al in one unit. was wary because of the low price (how can all these effects be as good as DBX's seperate units if the DriveRack is so cheap) and user-friendliness. now it seems like we don't need the crossover.

 

The DriveRack products are great. However, the PA will not allow aux-fed subs, because there are only L/R inputs. Check out the 260, which I believe has 3 inputs and much more flexibility. They can be had for just a few hundred more on eBay. If done correctly, you will get a lot out of the PEQ and GEQ's, RTA, crossovers, and limiters. Generally for live music, compression and subharmonic are not a good idea. You can search the forum for reasons why.

 

 

2) A DBX Sub harmonic Synth http://pro-audio.musiciansfriend.com/product/dbx-120A-Subharmonic-Synth?sku=183587 (with just one sub will it really make a difference? and the freq. response on the QSCs are only down to 45. I HAVE heard these things in action tho, and they really do work well - just not sure if our low end can take advantage/project what this sub harmonic synth will do.

 

Again, for live music, subharmonic synth is generally not used. It's more of a DJ thing. Adding a second sub will improve your low end way more than a subharmonic synth.

 

The DriveRacks are awesome, if you put in the time to set them up correctly. If you don't, they can make you sound worse, but that's the same with any product, really.

[mshifflett]

 

My .02 Pan all instruments for the mains to the left. Mixer L out > dbx231 ch1 > snake > fullrange input L main > full range out to R main. Pan kick & bass to the right. Mixer R out > dbx231 ch2 > snake > full range input on L sub > full range out to R sub.

 

 

You may want to leave the kick and bass center panned since there are frequencies of both that you will want reproduced in the top cabinets.

[6Imzadi]

Aux fed subs are not as difficult as portrayed here.

 

You need a crossover if your sub does not have that feature built in. You have to set the crossover input and output to unity to start.

 

Then;

out from aux send to crossover to snake to speaker (or amp if passive)

set the send to post fade. Most mixers have a switch for this.

turn up the aux send on the kick a little.

 

You've created a "sub volume level" for just those instruments that need the sub reinforcement.

 

On my mixer, my aux send is at unity and I cannot turn up the channel aux to the unity notch because it's just too loud. It is usually just under unity for the kick. Of course, your channel gain has to be up to the zero mark, or maybe a little above.

 

If this does not work for you and your sub sounds like there is nothing getting there, then you have a gain structure problem.