Home dbx User Forum dbx Archive Threads DriverRack PA & DriveRack PA+ PA General Discussion

Crisis: Advise needed

rjtmixrjtmix Posts: 4
edited June 2008 in PA General Discussion
A little history before the question:

Recently (this past week) we had a lightning strike on our building, which caused a loss of power, and our DriveRackPA unit was a casualty. The sound tech that designed the system moved 2000 miles away last month and there are no notes to current system design and settings. I am new to the congregation and a friend gave my secret away that I used to be a sound tech at the other church I attended. I was asked Wednesday if I could have the system functional by Saturday and I am just now getting the chance to become familiar with the system. I had the luxury at my other church of having EAW cabinets and processors, so unfortunately the DriveRack units that I heard a lot about are new to me.

The past few days I have taken a crash course on the DriveRack by reading the manual (twice), the “Getting Started� section of the forum, and all the posts that I could possibly read in the last two nights. The new DriveRackPA unit is being delivered tomorrow, so I will get my first opportunity to go through it then.

Normally, I would research it all out and take time to try different settings in order to optimize things, but I need some help with this one due to the time crunch. So Gadget and fellow forum members please have mercy on me and point to to previous posts or post a response
I said all that to simply say, if anyone could lend some advice, I would greatly appreciate it. The forum posts are great, but there is a lot of material to filter through.

Below is what I have been able to determine so far about the system design:

FOH speakers:

4 – Peavey ILS1294H full-range cabinets fanned out across the perimeter of the stage
Low Frequency Driver: 1000 W program
High Frequency Driver: 200W program
Frequency Response: 63Hz – 18.5 kHz
Crossover Frequency: 1600Hz
Impedance: 8 ohm
Box Tuning Frequency: 55 Hz

2 - SP 218X sub cabinets.
Low Frequency Drivers: 2000W Program
Frequency Response: 51Hz – 300Hz
Impedance: 4 ohm
Box Tuning Frequency: 40 Hz

Power Amps:

2 – Peavey PV2000
Per channel: 400W RMS @ 8 ohm 700W RMS @ 4 ohm
Bridged: 1400W RMS @ 8 ohm 2000W RMS @ 4 ohm

2 – QSC RMX 2450
Per channel: 500W @ 8 ohm 750W @ 4 ohm
Bridged: 2400W @ 4 ohm

FOH Mixer: 48 channel, LRM Crest Audio X-Eight

It appears that the current and original design was that the FOH speakers were full range stereo. Two speakers are paired in parallel with each other receiving power from one PV2000 bridged. With the Drive rack not functional I don't know what settings the tech was using.

Starting from scratch, here’s the game plan so far is to:

1. Bi-amp the system.
2. Set the crossover points.
3. Set the gain structure for the system as described in the dBx manual.
4. Balance the speakers
5. Set the limiter
6. Use the AutoEQ to determine which bands were boosted or diminished and add a parametric EQ at that band.
7. Revisit the system gains again.
8. Tune in EQ

Here are my questions:
1. The DriverackPA has Low, Mid, and High outputs available. Should I use:
Low outputs: 218X subs (51 -300 Hz range) with a BW18 filter at 300
Mid outputs: 12\" speakers in the ILS1294 cabinet (frequency range 63Hz – 1600Hz) for my low mids and set a LR bandwidth filter from 300 - 1600 Hz range for them? Or leave it from 63 – 1600

2. If I cannot bi-amp the system tomorrow, what would ideal full-range settings be?

In fact, what would be ideal settings for a bi-amped system. We will be bi-amping the speakers soon.

Please advise. Also if you have any other suggestions or settings for the DriveRack PLEASE let me know.

Thanks.

RJT

Comments

  • DRA1DRA1 Posts: 7
    test
  • DRA1DRA1 Posts: 7
    Sorry for the delay, but the site has been acting up for a couple of days. Hope this is in time.
    Here are some rough settings that should work.
    Subs:
    High Pass Filter (Low Cut) 50hz BW18
    Low Pass Filter (cross to top cabs) 100hz LR24
    Tops:
    HPF (cross to subs) 102hz LR24
    No LPF available.

    Remember that only use the Auto-EQ results to set the frequencies between about 160 and 600. Everything else should be tuned by ear.
    Use the gain set-up in the READ ME FIRST sect, it is clearer.

    When you say bi-amp, are you speaking of the tops only? Then your system including the subs would be tri-amped? If this is the case you will have to take 1 top cab outside to tune the speaker. There is NO WAY to do that inside because the room will REALLY mess you up.

    DRA
  • rjtmixrjtmix Posts: 4
    Thanks DRA. I meant tri-amped. It helped relieve some of the stress. We are functional for now. When we tri-amp everything will be even better. I realized today we are under powered some.

    I give props to the forum, you have been a great help.
  • GadgetGadget Posts: 4,915
    Ok we've established that your under powered...for the tops especially.. what were you going to use for the horns? or was it one channel for the lo mids and one for the horns?

    Use dra's plus add a 1800 hz xover (unless it's that 44XT driver) 1600 hz is too low and will hurt the longevity of the drivers...

    gadget
  • rjtmixrjtmix Posts: 4
    Gadget,

    Thanks for the response. The plan is to run new cable and buy additional amps, inorder to power the tri-amped system properly. Current design relies upon the passive crossover in the tops and one channel of the PV2000 amp is supplying power for one cab. Also discovered that the speaker cable is too low a gauge as well. Right now the crossover filters are set to DRA's suggestions below

    I'm new to the scene (literally began teching audio at this church this week), so I have identified a few improvements and will wait to see what happens. Tri-amping the system has been on their agenda already, so this should begin moving pretty fast. Up to now, I haven't had any opportunity to play with the system, but will definitely be able the next few weeks.

    Thanks for the crossover suggestion and all the other posts. It may be a while, but I will post results of the new design when it happens.
Sign In or Register to comment.