Crossover point for biamping tops

[tony k]

Hi All!

Can anyone give me a starting point for biamping my tops? I'll be using Peavey HDH244T's. I have the manual and it doesn't give any crossover points nor is there anything on the info plate on the back of the box. For reference it has a 15" woofer and a 4" compression driver into a 2" horn.

I usually cross the subs at 90hz if that makes any difference.

Thanks!

[tlbonehead]

Originally posted by tony k Hi All! Can anyone give me a starting point for biamping my tops? I'll be using Peavey HDH244T's. I have the manual and it doesn't give any crossover points nor is there anything on the info plate on the back of the box. For reference it has a 15" woofer and a 4" compression driver into a 2" horn. I usually cross the subs at 90hz if that makes any difference. Thanks!

I assume it is actually a 2" driver with a 4" voice coil? Is it titanium? I'm just guessing that somewhere in the 1500-1800hz range should work. Depends on how much power you are going to be putting into them and the slope of your crossover.

[tony k]

Thanks Tlb! I'll start from there.

As far as the compression driver, the manual only lists it as a "4 inch titanium compression driver". The unit itself is quite large compared to the 2" drivers on other cabs I've taken apart. Very heavey, I've never seen another c.d. this big. Is labeling it as a 4" driver possibly a mine is bigger than yours marketing hype?

[RickJ]

1.6kHz will get you above most of the musical fundamental frequencies, including vocals and guitars. I prefer the mid driver (15 in your case) to carry them. A cone is always smoother and warmer than a CD horn.

 

At 1.6kHz, the horn also picks up where the 15's dispersion pattern starts to get narrow.

 

Consonants, stick sounds, pick sounds, bass slaps and other percussives are handled very well by the horns, but they sound soft if handled by the 15 (or 12) mid driver. IMO, 2kHz is therefore too high.

 

1.2kHz is a bit low, since the crossover point is well within the range of the fundamental musical notes of most instruments -- guitar and piano especially. You don't want to have your musical notes or singer jumping from one driver to another.

 

Then again, PV (and EV and Altec and others') horns were originally crossed at 800 -- some as low as 500 -- so they can take a beating.

[agedhorse]

Depends on efficiency and power-bandwidth issues as well.

 

Somewhere between 1000 (taking advantage of high efficiency of horn-driver combo) and about 1600 should be good. Much higher and you may as well go with a 1" driver and get the benefits of the HF extension.

 

The unit has a 4" diaphram and VC with a 2" throat exit. Decent driver, not exceptional but certainly a good part.

[tony k]

Great info guys! That gives me a good range to experiment in. I'll have a lot of time for tweaking on our gig saturday. The owner of the bar we're playing at really enjoys listening to us and doesn't mind if we sound check for extended periods of time. Real cool guy. Should be a good place to tweak and get everything the way I want. This will be my first time with a tri amped system so wish me luck!

[J.]

Originally posted by RickJ

Then again, PV (and EV and Altec and others') horns were originally crossed at 800 -- some as low as 500 -- so they can take a beating.

 

Okay, you just answered a question I always had. When I look at the back of on old Peavey SP2 I always see the crossover frequency listed at 800hz, which is a heck of a lot lower than what a lot of cabs are crossed over at.

[RickJ]

J,

 

I believe it had more to do with efficiency than good sound. The horns were much more efficient than the cone drivers, and amplifier power cost a lot of money back then.

[tlbonehead]

Originally posted by J. Originally posted by RickJ Then again, PV (and EV and Altec and others') horns were originally crossed at 800 -- some as low as 500 -- so they can take a beating. Okay, you just answered a question I always had. When I look at the back of on old Peavey SP2 I always see the crossover frequency listed at 800hz, which is a heck of a lot lower than what a lot of cabs are crossed over at.

Most of those were cloth/phenolic diaphragms,which are a lot more forgiving and handle lower frequencies better than the metallic(titanium,aluminum)diaphragms. But most of them also ran out of gas in the 5000-6000hz range.

[agedhorse]

Depending on the models, Altec and EV both used aluminum (Altec 800 series) as did JBL, Peaver etc.

 

Phenolic bacame popular in the 2" exid drivers, notibly the 291 (280????) by Altec, and the 2480 by JBL, the EV 1289(?) plus a host of others.

 

Yes, the tradeoff was indeed limited HF response.

[tony k]

That makes sense Mark. They do indeed have a 2" exit on them mounted to a 2" throat.

Maybe they can start rating them by weight just like some of the wild claims I've seen on 15" drivers. I'd swear I've seen claims of 20lb magnets lol!