Dance Club Sub Box Help!

[Mike Caldwell]

Hello
Getting properly tuned boxes is a must but double check the high pass filter on the amp. What is the cut off rate it will listed something like 12db per octave or 18db, the higher the better. Is there an eq in the system that has everything in the sub low frequencies boosted to max? Also check and double check the system polarity/phase if one of the cabinets is backwards from the rest or even a speaker in the cabinet is reversed from the other that will significantly reduced your low end output make you want to drive the system harder to make up for it. If your system is connected with balanced cabling a simple mis wiring flip of + to - in a connector can cause the same thing. A peak stop limiter of any kind will only protect the system so far if the operator is determined to keep pushing into the limiter.

Mike Caldwell

[Zilch]

Am I missing something here?

It seems to me that the original post indicated a thermal failure due to voice-coils burning up.

Nope. Earlier observed at #4:

Consider 2241 and 2242 as potential upgrades. Run their sims to see how they'll play. It's not overexcursion that's smoking voice coils.

Get more powerful drivers running in a proper alignment and using an infrasonic filter.

DJ buys all recones after that....

[mech986]

Is there a consideration about how the room is set up? A 25 x 25 foot square room with 3 speakers in the corners and the DJ in the last corner doesn't sound like a place where the DJ would be able to hear accurately.

I'm thinking that there may be considerable room nodes and that the DJ placement and/or speaker placement could be a problem. I know it may be impractical to move the speakers but I would be concerned that the DJ is pushing the LF or VLF trying to compensate for poor room acoustics. Or the DJ is pushing the amp into clipping or hard current limiting with the setup that is in place. Or the DJ's hearing is already damaged severely and is unable to mix properly - I am not kidding here, the type of DB levels this system can put out will cause damage over time and can compromise any person's ability to make good choices based on what they hear.

I agree with Mike that the absolute polarity of the system should be checked, especially since the drivers have been taken in and out a number of times, very easy to get the crossover/driver wiring out of phase.

Seems to me (without the benefit of software) that 2 of these beastie subs should be real sufficient to drive that size room, properly tuned and placed. Has the original poster done any evaluations of the room acoustics and or run some RTA measurements from various points in the room?

DJ buys all recones after that.... : AGREE, he who pushes the sliders, pays for the damage!

My 0.02.

Regards,

Bart

[GordonW]

Personally, I'd look at better amps.

I've seen a number of those Mackie 1400i and 2600i amps come in for service... and our service guy swears at them, regularly. Just not terribly stable, compared to stuff like QSC and such.

If you can't afford the Crowns, I'd look at something like QSC 4050HDs and such. Good, stable, easily-repaired amps.

Also, I'm still unclear on how the amps are wired to the subs... three sub cabinets on one amp? Is it bridged, or is there one sub on one channel, and two on the other? You DEFINITELY don't want to be bridging Mackie amps... PERIOD. Really makes them hot-headed, IME. I'd look at getting a 4th cabinet, and run two per channel... that'd be a safe, 4-ohm load. Get an amp that's big enough to run stereo into 4 ohms, and get the power you need per woofer. A QSC 4050HD would be just about right, for 4 2240s...

Regards,
Gordon.

[Mike Caldwell]

Hello
Is there a mix and match of drivers in different cabinets, McCauley and JBL? JBL's with the exception of the latest neo drivers move back wards with positive to the red terminal.
If your are bridging your amps are you connecting the speakers to the two red binding post on the amp. If you are connecting the speakers to the red and black terminals per channel while bridging an amp you will automatically have them inverted from one another and not gain any increased power.
Like was mentioned before I would look into a more professional power amp or amps with enough power to give you the headroom you need. As for the power rating of your Mackie 2600 and a Crown MA2400 they just about identical. While the Crown is definitely a pro solid amp and I would say will sound better you would still be a little short on power.
How are you connecting and driving the three cabinets you have.

Mike Caldwell

[scott fitlin]

Crown is no longer manufacturing the MA-2400. So, you are looking at buying used amps. I personally prefer buying new if you can.

Crown has the new XTI series, and the iTechs, go and have a listen to them.

But, you should also consider QSC! They are rock solid reliable, like Crown, and they sound very good, and are more cost effective.

If you can, get your local amp dealer to loan you two amps, one QSC, one Crown, of the size you need, and audition!

[Izzy Weird]

Perhaps you don’t have enough subs for the volume level and the dance floor size.

25’ by 25’ is not that small for a dance floor. In the past I have used a quantity of eight 18” vented box subs on dance floors that size, a pair of them in each corner for example. I often used cabinets custom made by EAW that were 12 cu ft internal. They had large removable ports so we could easily change the tuning. They were 42” tall so they could be used as drink rails, and had aluminum edges to keep the drinks from vibrating off.

At one club I remember, Studio West in San Francisco, it was almost impossible to get the DJ to run at less than insane volume levels. So I added a slow gain-riding limiter. The DJ’s absolutely hated it. At Studio West, the management was opposed to increasing the subs from eight to sixteen units, mainly because of the room they would have taken up. They kept a spare set of eight drivers, and were perfectly willing to have them re-coned frequently.

If the DJ is well out of the sound field then the problem can be worse. If the DJ cannot hear how loud it is for the customers, he may run the system too loud. Some tests have shown that the threshold of discomfort is about 6 dB lower for women than men. So an excessively loud system may drive the women out first.

Yes, do try to educate the DJs. No sound system has infinite headroom. Educate them as to where the limit is, especially for the sub channel. Put a level meter on the sub channel. Explain how a DJ’s temporary hearing loss can cause them to slowly raise the volume level over the course of an evening.

The typical high-pass filter we used was 25 Hz @ 18 dB/octave. The cabinet tuning was done by EAW and was a QB3 alignment with an f3 of 30 Hz. if I remember correctly. Most clubs that used these subs had systems that were very loud but did not have frequent failures.



Izzy

[Mike Caldwell]

Hello
The MA2400 is now the 2402, the biggest change was being able
to accept the latest version PIP input cards. They went to the "02" version in every MA model except the 3600vz, from what I heard there was not enough space in the 3600's to so what was needed. I used the MA3600vz's with the EDCb PIP cards. The MA600 was dropped from production. As for the XTI amps, from what I have read them seem to suffer from various glitches in operation. I second what Scott said about QSC, all of my amps with the exception of the MA3600vz are QSC PL2 series.

Mike Caldwell