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8 ohm woofer 16 ohm hf horn crossover plans?

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darcyl

New Member
Hi there, I'm cobbling together some stuff I have laying around, and would like some advice on building a crossover for the system. The woofers are Celestion G15-150 8 ohm, going into JBL 4530 cabinets, with TOA HFD-220-16 16 ohm drivers mounted to Renkus-Heinz SSH-500 horn lenses. I know this is probably far from ideal matching of components, but I have the stuff, so I'd like to play with it. I know I can calculate a crossover for 8 ohm driver, and a 16 ohm tweeter separately, but when hooked to the amp, what impedance would it see? I will be driving these with a Triode Electronics ST70, and I want to be sure the amp sees a 8, or 16 ohm load- Any help is greatly appreciated- Thanks, Darcy
 
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Don't worry about the load the amp sees. Actual driving source impedance will be a few ohms or less. As for reflected load to tubes, that is not constant anyway...it is a range.

Just calculate it out for 8 and 16 and fire it up. Hook up to whichever tap sounds better.

SSH500 is a pretty good horn.

I have the TOA tweeters but never tried the compression drivers. They are probably decent also.

Sounds like a worthy project to me.
 
Quoted impedance is almost irrelevant for crossover design anyway. Start by measuring the frequency range and choosing a crossover point, next measure the driver impedance at the desired point.

Then look at the relative SPL of the two drivers, and work out whether to attenuate the treble driver before or after the crossover. Attenuation in this case will have the advantage of reducing the HF driver impedance (with some parallel load) so presenting a more linear load.
 
The above post would be the most accurate way. Ideally you'd want to get impedance curves for the drivers and use modeling software. Short of that, you could do this:

http://www.diyaudioandvideo.com/Calculator/XOver/

This calculator lets you input nominal impedance of each driver (8 and 16) and a crossover frequency, and it spits out designs for various crossover types. Not as accurate as driver modeling but it may be a good starting point.

Is the woofer well suited to the cabinet size and type (ported)?
 
darcyl said:
Hi there, I'm cobbling together some stuff I have laying around, and would like some advice on building a crossover for the system. The woofers are Celestion G15-150 8 ohm, going into JBL 4530 cabinets, with TOA HFD-220-16 16 ohm drivers mounted to Renkus-Heinz SSH-500 horn lenses. I know this is probably far from ideal matching of components, but I have the stuff, so I'd like to play with it. I know I can calculate a crossover for 8 ohm driver, and a 16 ohm tweeter separately, but when hooked to the amp, what impedance would it see? I will be driving these with a Triode Electronics ST70, and I want to be sure the amp sees a 8, or 16 ohm load- Any help is greatly appreciated- Thanks, Darcy
Click to expand...

I see this thread is 2 years old, but just wondering what ever happened to this project?

I am assembling a similar setup.
 
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