Argggggg! Failure at a teen dance last night

[rec]

20 minutes before the end of the dance I lost the mids and highs by about 90%. Meaning I could hardly get any thing
out of my OT12's. I dont suspect the speakers as it is very unlikely that they both failed. I am running a 2 ch DJ mixer into a DRPA+ to a QSC GX5 for the tops. I am going to investigate this afternoon in the garage. I can tell you that the main LED's on my mixer would barely move as compared to the rest of the night they would jump up to about unity or a little over. Also no activity on the DRPA for the highs once the failure occurred. Did the amp go into thermal protect, I would think not as I only had the attenuators at 14-16 which is about half. So anyway I will check into it later today and post my findings. My subs were still working. As a side note I struggled with sub cancelation. Some of the kids said that they could not hear the bass at the back of the cafeteria. More on this later.

[doncolga]

20 minutes before the end of the dance I lost the mids and highs by about 90%. Meaning I could hardly get any thing
out of my OT12's. I dont suspect the speakers as it is very unlikely that they both failed. I am running a 2 ch DJ mixer into a DRPA+ to a QSC GX5 for the tops. I am going to investigate this afternoon in the garage. I can tell you that the main LED's on my mixer would barely move as compared to the rest of the night they would jump up to about unity or a little over. Also no activity on the DRPA for the highs once the failure occurred. Did the amp go into thermal protect, I would think not as I only had the attenuators at 14-16 which is about half. So anyway I will check into it later today and post my findings. My subs were still working. As a side note I struggled with sub cancelation. Some of the kids said that they could not hear the bass at the back of the cafeteria. More on this later.

Well at least it was 20 minutes left instead of 20 minutes into it...that would have been even worse. Good luck locating the problem...I know that's frustrating.

[J_Dunavin]

sorry man that really stinks!

As far as the subs go:
Give us a room lay out, and where your subs where located.

[netwerks]

20 minutes before the end of the dance I lost the mids and highs by about 90%. Meaning I could hardly get any thing
out of my OT12's. I dont suspect the speakers as it is very unlikely that they both failed. I am running a 2 ch DJ mixer into a DRPA+ to a QSC GX5 for the tops. I am going to investigate this afternoon in the garage. I can tell you that the main LED's on my mixer would barely move as compared to the rest of the night they would jump up to about unity or a little over. Also no activity on the DRPA for the highs once the failure occurred. Did the amp go into thermal protect, I would think not as I only had the attenuators at 14-16 which is about half. So anyway I will check into it later today and post my findings. My subs were still working. As a side note I struggled with sub cancelation. Some of the kids said that they could not hear the bass at the back of the cafeteria. More on this later.

If you are saying the "main led's on my mixer would barely move" thats an indicator to me the signal going into the mixer was too low. So perhaps there is an issue with the line signal source of music going into the mixer. Dunno if you're using a computer, cd player, m3 player or what, but check that first.

[Frederic Gelinas]

I can tell you that the main LED's on my mixer would barely move as compared to the rest of the night they would jump up to about unity or a little over.

The signal didn't get out of the mixer. The problem is probably at your source level (cd player/computer?) or from your mixer. I'd check that first.

[SoundInMotionDJ]

I can tell you that the main LED's on my mixer would barely move as compared to the rest of the night they would jump up to about unity or a little over.

The signal didn't get out of the mixer. The problem is probably at your source level (cd player/computer?) or from your mixer. I'd check that first.

+1

Beginning with the source of the music, trust nothing, check everything.

[rec]

Well I after much testing and playing around I am still not sure what happened. Both OT12's were equally muffled when playing.
I checked the basic things first, no loose cables, none of my mixer settings got bumped, etc... I am using a computer DJ software (VirtualDJ) running a 2 channel Urei mixer and a Native Instruments sound card.
I hooked everything up the same way I had it last night and the OT12's just would not come up to volume. I borrowed a DR 260 from my work and got every thing dialed in, ie: gain structure, and limiters set. Every thing sounded fine in the garage.
I just had one sub connected and both OT12's. I was shaking the house and had all the volume I could stand from the OT12's. By the way I was wearing hearing protection. Turned everything back off and reconnected my DRPA+ and it just does not sound right. I setup a different DRPA+ preset with all the custom speaker settings, gain structure, limiters, etc and that did not make a difference. I think there is something wrong with my DRPA+, but I still need a little more time to be sure.
I matched all my EQ settings on both the DRPA and the 260.

On a side note I have 2 amps QSC 1850HD and a GX5. Normally the GX5 is for the OT's and the 1850 is for the subs. For a test I tried running the OT's on one side of the GX5 and the sub on the other. Bass was slamming as normal, and had more than enough volume from the OT's. It has become evident that the 1850 is not enough amp for my t30 subs (4012HO drvs). I have to run the 1850 attenuators almost to clipping to get the t30's to sound the way I like, but the GX5 I had head room to spare when driving the sub.

I will see if I can get a picture of the cafeteria or at least the dimensions as I am sure that I will be playing there again

[Drey Chennells]

Rec, you'll find it. Like the others have shared with you, remove and replace components in the signal chain until you find the culprit. I'd start by making the system as basic as possible, running another signal source right into your amp. should be fine, if it's not, you know it's the amp. Then run the signal thru your processor. Still good? hook up your original source and so on. swap cables as well.

[netwerks]

Rec, you'll find it. Like the others have shared with you, remove and replace components in the signal chain until you find the culprit. I'd start by making the system as basic as possible, running another signal source right into your amp. should be fine, if it's not, you know it's the amp. Then run the signal thru your processor. Still good? hook up your original source and so on. swap cables as well.

Drey exactly my point earlier. Remove everything and start adidng pieces back into the chain one by one until you see the problem reproduce itself. Don;t have the mindset of "what is it" rather have the mindset of "what is it not".

It sounds to me like you've got a problem before the mixing board. I would take a computer and a voltmeter and run a test tone from that computer all the way through the signal chain and make sure you get an even signal all the way to the speaker.

BUT. One other thing you may want to look at as a LAST resort is the crossover wiring inside of the OT12 and double check it. Make sure it it per the plans and everything is soldered correctly etc.

[Ron K]

Really sounds like the DRPA+ took a crap on you. Since you tried a known good unit and it worked fine I'd look at the DR. Perhaps you took out the input opamps?

Go through all the settings manually and double check that there are no limiters or compressors working against you.

[rec]

Well I am chasing a ghost at this point. Currently my system is working fine with my DRPA+. I have a Christmas gig this Saturday evening so
we are going to get there a little early and see what happens. I am taking the DR 260 all dialed in so if something goes wrong I can do a quick swap.

[Nate Rouslin]

It has become evident that the 1850 is not enough amp for my t30 subs (4012HO drvs). I have to run the 1850 attenuators almost to clipping to get the t30's to sound the way I like, but the GX5 I had head room to spare when driving the sub.

I will see if I can get a picture of the cafeteria or at least the dimensions as I am sure that I will be playing there again

The rmx 1850hs is more than enough to run your T30s. I use to run rmx 1450s bridged mono to T36 with 4012hos and they ran fine. Sounds like you are having an input issue with the 1850.

[Ron K]

Well I am chasing a ghost at this point. Currently my system is working fine with my DRPA+. I have a Christmas gig this Saturday evening so
we are going to get there a little early and see what happens. I am taking the DR 260 all dialed in so if something goes wrong I can do a quick swap.

If it does it again I would be looking at that DRPA with a possibly failing input opamp or an output opamp on channels 3-4. I'm pretty sure they share a chip where both opamps are inside that common chip.FWIW DBX has decent and quick service. I have one here that's got a similar problem but it's on output#5. Meter shows output but absolutely no signal coming from that channel. It worked fine for a few jobs and then it started acting up to the point where it no longer works at all.It's on it's way back to DBX as I haven't got the time to mess with it. To be honest I really think the DRPAs are kinda week in available configurations and functions.I've replaced them all with Ashley,Behringer and Xilica units.

[rec]

Here is a link to some pics that may help you help me with sub placement. Does not seem to be a lot of choices here.
When looking at the stage there is a short wall to the right that I could potentially wall load.
I thought even having the subs side by side in front of the stage pointing towards the dance floor might have worked better.
I dont have dimensions but I can get them.
http://s260.photobucket.com/albums/ii31 ... FM%20pics/
Thanks ahead of time

[SoundInMotionDJ]

Here is a link to some pics that may help you help me with sub placement.

Ugh...that room doesn't offer an easy option for sub placement. The subs are currently stage right (standing on the stage...the subs are to the right).

The wall on stage left may be an option.
Clustered in front of the stage may also be an option - skip the V-plate and just point them straight out.
Corner loaded BEHIND the table on the stage may also be an option.

In either of the last two options, you will be pounded to death by the end of the gig....in case you're into that kind of thing.

Aside: What's the DJ program you are using? I can't see the screen well enough to recognize the program.

--Stan Graves