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Church and H.O.W. Forums for HOW Sound and AV - Your Displayed Name Must Be Your Real Full Name To Post In The Church and HOW Forums => Church Sound Archive => Topic started by: nturner on August 27, 2004, 10:22:06 pm

Title: Bag End Sub EQ
Post by: nturner on August 27, 2004, 10:22:06 pm
This is my first post.  If it's in the wrong forum, please point me in the right direction.  I'm not familiar with LAB by the way.

Anyway, I'm the media Technician for a large church.  We have a great system with the exception of one thing, the subs.  The original engineer put them half way back under the stairs that lead up to our balcony.  Because that's such a poor location because of delay and other issues, I moved them up to the stage (I wish we could put them under the front steps, but our stage is concrete, so it would be a costly project).  

I'm having problems getting them to sound good.  They are two Bag End Quartz (4x18").  I want them to sound more "punchy" than "woofy".  I know it is a little harder to get 18" woofers to sound like that, but I knew I could do it when a concert that came to our church brought 4 of the same thing that sounded great.  I'm using a Sound Web for the EQ/Crossover.  Right now, I have them crossed over at about 75Hz.  I've played around with all different settings and just can't get them to sound right.  Is there any type of EQ I should put on them?

Thanks for your help
Title: Re: Bag End Sub EQ
Post by: Tom Young on August 28, 2004, 05:59:35 pm
It would appear that what is lacking is the ability to optimize your subs.

This requires using a 'complex' measurement system (such as Smaart, SIm or TEF) and measuring the response of the subs. You will first determine that they are in a beneficial position and that they are in correct polarity.  Then you apply corrective EQ, delay alignment and dynamics control.

As you have observed, the subs *can* work very well. There's no 'magic bullit' of advice or settings that anyone can pass on to you, even the manufacturer. All ldspkrs behave in a specific and unpredictable manner when placed in a space and interacting with one another. This needs to be measured.

I would look for a measurement maven and have them do this work.  It'll cost, obviously, but the result will be pretty amazing assuming you hire a seasoned measurement and live sound pro.
Title: Re: Bag End Sub EQ
Post by: Dan J Sullivan on August 29, 2004, 12:10:39 pm
I am not familiar with these subs so do not know suitable crossover points.
However if you are looking for punch then you will need to cross far higher than 75hz,  you will find the main punch in the 100-150hz region.



Having just looked up the specs I found this:
Recommended Crossover Frequency:
80 Hz

Frequency Response:
18 Hz to 65 Hz +/-2 dB
(2 pi Steradians, with
8 Hertz Integrator)

It is not therefore advisable to raise the cross over frequency,  this how ever means that you will not be able to acheive a great deal of punch from these cabs.  What cabs are you running above these?
Title: Re: Bag End Sub EQ
Post by: nturner on August 29, 2004, 03:05:08 pm
I've got 10 EAW MQV 2394 ( on the main ring, then 7 EAW ASV7932 (discontinued, but equvialent is MQV1394e delays for a balcony.

Maybe I need to have our engineer come back and TEF the room (Kinda Costly).
Title: Re: Bag End Sub EQ
Post by: Tom Young on August 29, 2004, 03:10:11 pm
This may be a case of semantics.

I think of "punch" from subs as tightness and power, which has nothing to do with crossover point.

In most cases I have been a part of and in observing live audio folks and systems "all over" I find it is very seldom useful to cross subs over at a frequency that is above 100Hz.  This is (in part) due to the transition point that subs need to have in their interaction with the ldspkrs above them.

I reiterate my original post: if the subs be lackin' your optimization be slackin'.
Title: Re: Bag End Sub EQ
Post by: john abney on August 31, 2004, 05:47:29 pm
What amps are you using? The amps that can keep going at 1600 watts continuous all day don't all sound alike.

An amplifier that is a perfect match from a hundred Hertz up may not always rock your world when used with subs.

Maybe a side-grade to a different flavor of amp might be a better fit for the room.

Also, are you able to place the subs on the floor in front of the stage? Toward the middle? The Quartz looks like an industrial design pulpit without the slanted lectern. But you might have a hard time convincing the preacher of using a sub for that Smile.
Title: Re: Bag End Sub EQ
Post by: nturner on August 31, 2004, 11:12:53 pm
I'm using a Crest Audio CA-9 Amp per cab.  Half of the amp powers half the cab and the other half of the amp powers the other half of the cab.  

Off the top of my head, I don't know how many watts these amps are.  I do know that there are only two more large CA series amps than the CA-9.
Title: Re: Bag End Sub EQ
Post by: gainreduction on September 06, 2004, 11:47:35 pm
All the Bag End Sub Systems I've come across utilize their sub processor for proper tuning.  The INFRA Integrator it's called.  Have you talked to the guys at Bag End yet?  I'm sure they'd be happy to help.