Small Venue :: DRPA, DRStudio :: Help with total x over settings 

Author

Message

riverjordantheband.com

member since: 08/07/2004
messages: 4
 

I am running a pair of sf15 and G-734 connected together to drop it down to a 4 Ohm load on a Crown CE2000

and

2 pairs of Peavey SP 118s 8 Ohms each on a Crest cpx 2600.

All running stereo.

Please tell me how to configure the crossover and subharmonic, as will as any other setting I need to give the best sound. Thanks Tommy

riverjordantheband.com

member since: 08/07/2004
messages: 4
 

OK I will try again,

Tops: JBL SF15 and JBL G-734 both pairs have 15" and a horn
All 4 speakers are 8 Ohms

Specifications: JBL SF15
System Type: 15" 2-way, sound reinforcement speaker
Frequency Range (-10 dB):2 38 Hz - 16 kHz
Frequency Response (±3 dB):2 50 Hz  12.5 kHz
Sensitivity (1w/1m): 98 dB SPL
Nominal Impedance: 8 _
Power Capacity:1 250 watts
Peak Power Capacity:1 1000 watts
Maximum SPL: 128 dB
Nominal Dispersion: 90° x 50°
Crossover Frequency: 1.6 kHz
High Frequency Driver: JBL 2412, 1" exit compression driver mounted on
Progressive
Transition" Waveguide
Low Frequency Driver: JBL M115-8A


Specifications: JBL G-734 === Attached

Both sets are running on one Crown CE-2000

Bottoms: 2 pairs of Peavey SP118x

Specificatoins: Peavey SP 118x

8 Ohms
Frequency response, 1 meter onaxis,
swept-sine in anechoic
environment:
50 Hz - 300 Hz (±3 dB)
Usable low frequency limit
(-10 dB point):
31 dB
Power handling:
Sub Bass Section:
500 W continuous
1,000 W program
2,000 W peak
Sound pressure level, 1 Watt,
1 meter in anechoic environment:
Sub Bass Section:
98.0 dB SPL, (2.83 V input)
Maximum sound pressure level
(1 meter):
Sub Bass Section:
125.0 dB SPL continuous
131.0 dB SPL peak
Transducer complement:
Sub Bass Section:
1 x 18" woofer, vented
1808-8sps BW
Box tuning frequency:
Sub Bass Section: 39 Hz
Harmonic Distortion:
1% rated power
2nd Harmonic:
100 Hz: 0.37%
1 kHz: 0.46%
3rd Harmonic:
100 Hz: 0.23%
1 kHz: 0.59%
10% rated power
2nd Harmonic:
100 Hz: 0.82%
1 kHz: 1.68%
3rd Harmonic:
100 Hz: 0.53%
1 kHz: 0.74%
Impedance (Z):
Sub Bass:
Nominal: 8.0 Ω
Minimum: 7.5 Ω

The 118's are running off one Crest CPX-2600. If you need the specs on the amps I can provide that.

I have a rock band that plays in many different arenas as well as outdoor stages. Thanks Tommy

Attachment(s): 734.pdf  

Mikeyman

member since: 01/19/2006
messages: 43
 

What kind of DriveRack are you using?

First, I wouldn't recommend using two different kinds of tops. You are going to get all kinds of phasing problems where those horns overlap.

That said, let's get a basic crossover going:

Set the DR to a two-way config. The HFP for the Sub should be set for a BW 18 at about 35-40 Hz. Use a L-R topology at 24db/octave between the subs and the tops and set the crossover frequency at 108.2 Hz for both. Delay the tops by 8.00ms for starters and sweep the delay by 0.50 ms intervals between 6.5 and 11 ms to provide the most solid sounding kick drum (use recorded material). The 8ms mark should be pretty close for that config and front loaded subs.

As for gains, that's a tougher question. Set the sub output to give you the amount of low end that you want and then look at the crossover frequencies again. Since the sub will likely be haystacked by about 12 dB (acoustically, not electrically) for a simple rock and roll setting, you will likely move the sub crossover a little lower and/or the top crossover a little higher. That will compensate for the apparent or acoustic crossover shift by not having the gains equal. If you want to understand this, just draw the crossover slopes and move the subs up. The actual crossover frequency shifts to the right as the gain on the sub is increased.

As for EQ, you can look elsewhere on the site for how to do all that stuff. This crossover setting should work pretty well, though.

Without measuring the system, it's difficult to tell exactly how to set it up "correctly." There are plenty of good resources on this site to help fiine tune your system.

Good luck,
Mikey

riverjordantheband.com

member since: 08/07/2004
messages: 4
 

And Thanks for the reply Mikey!!

Gary Perrett

member since: 06/24/2004
messages: 901
 

Yup... that would be a good place to start... You could lower the sub to SRM xover but try that first..
Gadget