Low crossing of Compression drivers

[reins]

Hi,

There is a lot of discussion ongoing about using Pro drivers for home hifi.

Normally 1" compression drivers are crossed higher than 2kHz. I wonder how low such an driver could be crossed in a home system with less demand of SPL. Would it be possible to cross as low as 800-1kHz for medium listening levels?

Regards
Stephan

[GM]

Greets!

Maybe, depending on the driver/horn used........

CD horn EQ will be required if a horn suited for the new Fc isn't used and power handling will drop 4x with each lower octave it's required to reproduce, so on a stock 2 kHz horn you won't be able to reduce it much even with a steep XO slope. Note too that the driver's rear chamber (CC) volume (Vb) may need adjustment for best performance.

Bottom line, unless you're prepared to do some measured testing of a driver/horn combo to find its acceptable audible distortion BW and required XO point/slope, best to use a driver/horn rated for the desired BW. Or you can try these suggestions, though not the dims unless the same horn is used: Extending a high frequency horn to achieve a lower cutoff

GM

[EspenE]

Originally posted by reins
Hi,

There is a lot of discussion ongoing about using Pro drivers for home hifi.

Normally 1" compression drivers are crossed higher than 2kHz. I wonder how low such an driver could be crossed in a home system with less demand of SPL. Would it be possible to cross as low as 800-1kHz for medium listening levels?

Regards
Stephan

Depends on what you call "normal". The JBL studio monitor series cross the 1" compression tweeter (2416H in 4425, 2426H in 4430) at 1,2 kHz (4425) and 1 kHz (4430).

And these studio monitors (4430) can play up to 120dB SPL with distortion levels lower than 1%.

I would say you definitely can cross 1" compression tweeters at 800-1kHz, given that you choose a good unit, dont't use first order filters (which never would sound good anyway), and that your definition of listening levels is more or less "normal".

EspenE

[reins]

Uups, some how I missed the other thread.

While the necessary horn loading is quite clear, the problem with the CC volume was new to me.

Could the driver be damaged with listening levels up to say 95 dB with a lower crossover? I don't think so.

Thanks for the answers,
Stephan

[GM]

95 dB transients or average? If average, then distortion will probably be audible in the form of harshness in the lower octaves and some symphony transients may even cause them to bottom out, making a sharp 'clacking' noise (been there, done that and got the bills to show for it. ).

Really, the time honored way to do this is by doubling up on the horns/channel and rolling one off so as not to screw up the HF response.