Impedence question - Klipsh crossover (Off Topic)

by GC, Thursday, May 19, 2005, 04:06 (4633 days ago)

Hi all,

Can anyone help me with this? I am building a modified Lascala set up using a wood horn midrange section that will be driven by a 10" cone mid driver (perhaps JBL 2012 or similar - haven't decided). My question is regarding impedence. I believe the stock klipsch drivers are rated at 4ohm for the woofer, 16 ohm for the mid and 8ohm for the tweeter. If I use the stock klipsch network, must I use drivers with the same impedence? This is really only a question for the mid driver as I need to know if I should stick with 16 ohm? Can anyone enlighten me?

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Impedence question - Klipsh crossover

by GC, Thursday, May 19, 2005, 09:09 (4633 days ago) @ GC

Hi Jcaques,

If I use the stock klipsch network, must I use drivers with the same impedence?

A crossover is based and tuned on the exact drivers used in the system. If you want to use the stock crossover then you should use stock parts too.

Changing a driver means changing the filter because another driver/horn is different in sound, sensitivity and performance. Its not just a matter of using drivers with the same impedance...

Ciao,

Bert

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Impedence question - Klipsh crossover

by GC, Thursday, May 19, 2005, 15:19 (4633 days ago) @ GC

Thanks,

It's the crossover piece that confuses me the most in terms of speaker construction. While I understand in general terms what the crossover is doing, I am far from being proficient in understanding it. I have, however read some articles where certain drivers have been substituted for the stock mid horn in the Klipsch designs - apparently successfully - using the stock networks. Your original comments aside and acknowledging that the networks were not designed for other drivers, is the impedence a critical factor? That is, will I fry the crossover with an 8 ohm driver or will it draw too much power away from the woofer and tweeter? Assuming similar efficiencies for the horn I am proposing in comparison to the stock horn (the tweeter and woofer are stock), should I stick with a 16 ohm driver?

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Impedence question - Klipsh crossover

by GC, Thursday, May 19, 2005, 15:41 (4633 days ago) @ GC

Hi Jacques,

horn (the tweeter and woofer are stock), should I stick with a 16 ohm
driver?

If the driver you want to replace is 16 ohm then the other driver should be 16 ohm also. You could add an 8 ohm resistor in series with an 8 ohm driver for 16 ohm as result. The filter will then basically see the same impedance and will cross at the frequencies it was designed for.

But, adding a resistor reduces the sensitivity and if there is an impedance correction network present in the standard filter than the expected results will probably be different than wanted.

A driver is also NOT an 8 or 16 ohm resistor, that is only when measuring the driver with DC (as most multimeters do). A driver has a coil and the real resistance on AC (music!) rises with rising frequency and rises on resonances.

Another driver probably has another coil with different Rdc and inductance. So, expect a "mismatch" if you use something else than designed.

The system or filter won't burn or break but a driver with another impedance will shift the crossover frequencies and when the mid-driver receives too much lower frequencies then it can break down when playing too loud.

I hope this clears things up a bit...

Ciao,

Bert

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Impedence question - Klipsh crossover

by GC, Friday, May 20, 2005, 02:38 (4632 days ago) @ GC

Thanks Bert,

Your response does help a lot. I do understand there's a degree of chance in my experimentation - but what the heck! As a rookie I expect to make some errors, but the fun is in the trying. Having a forum like this one is a great help to those like me who are less than expert in terms of technical knowledge.

Cheers!

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