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Why push the midhorn crossover down always, why not 1Khz for instance?


JL Sargent

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Seems everybody is always wanting to go lower into the midhorn. Seems every 15" woofer out there can do 1Khz+ no problem. Yet we want to get out of it and into the horn ASAP. IE: the 400hz into the K400 horn. Is it the sound preference of horn over K33 or is there other stuff I'm anxiously waiting to learn about?

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I'm speculating here...

I think most of these conversations are based around using Khorns and with Khorns the high frequency cutoff of the bass bin is the problem. Since you can't get the bass bin to go higher, the logic is, take the midrange down lower.

The Jubilee was designed in part (if not primarily) to address this issue and succeeded in raising the crossover point that the Jubilee can use, allowing those people to use a higher crossover point and opening up a much wider circle of midrange possiblities.

Perhaps someone will correct my errors of presumption.

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1.) A 15" woofer beams at approx 900hz (930 - 960).

2.) secondary harmonics due to crossover roll offs would result in a lot of material within the beaming range of the driver due to how crossovers roll off on a per octave basis.

3.) In the case of the Khorn, it's a poor cabinet to reproduce above 350hz......there's a clear dip between 200 and 400 hz. You can forget about using a khorn to fill between 400 nad 900hz.

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"squonky" That not good.

Im planning on crossing my 2441s at 500hz like you previously recommended Fritz. I keep seeing horns though that apparently can go 300ish. Always trying to learn something. Thanks guys.

Coytee, where are you crossing your Jubes with the actives?

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The cut off of 500hz using a 12db per octave driver is what JBL says will provide 70 watts of power handling on the 2441. If you use a 6db per octave xover, your power handling will be less. If you crosover at a lower frequency...power handling will also be less.

If you put the 2441 on a horn that can handle 300hz, and cross the driver over at 500hz, the horn will still sound better than putting the 2441 on a horn that handles 500hz while using a 500hz crosover. The reason is that on a 300hz horn, even if crossover at 500hz, you still get some coverage below 500hz due to the way the crossover rolls off gradually at the per octave rate. If you use 100db as a reference point at 500hz using a 12db per octave xover, the level would be just below 100db at 480hz, at 240hz the level would be 88db, at 120hz 74db, at 60hz 62db, etc.

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Generally, I try to crossover where the polar response and distortion response are similar...this helps makes the transition less noticeable. Though it's always nice to cross not right in the middle of the midband (~3kHz) as our hearing is more sensitive in that region.

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Thanks for that link. Heck, they recommend crossing into it at 1000hz yet low usable freq 550.[*-)] On the active crossover I can go down to sub 400 before it starts to sound different to my ears. I've got to get me a mini-analyzer or similar. Ill have to think the horn over. I really like the way it sounds but what do I know? I'm gonna listen tonight crossing into it at 1000.

Michael, thanks for noticing my avatar. Thats my son (audio lab assistant) Auston. We have a big time of it.

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Generally, I try to crossover where the polar response and distortion response are similar...this helps makes the transition less noticeable. Though it's always nice to cross not right in the middle of the midband (~3kHz) as our hearing is more sensitive in that region.

Hmmm, that sounds good. I'm gonna investigate that. Maybe I'm smart enough to figure out where that is........

Reading up on horns and it appears this one might be better for me. Reported with minimum crossover at 500hz.

http://www.jblpro.com/pub/components/2380a.pdf

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For what it's worth, I'm not a huge fan of the 2380A....mostly
because it's got a diffraction slot. That's not to say that it's a bad
horn - in fact, I've mixed in many venues using some variation of the
2380A for the main speakers and it's not too hard to get things
sounding good. However, I think there are better alternatives available.


You might try browsing through some of the horns here:

http://www.usspeaker.com/homepage.htm

(click on horns in the column on the left)


I would expect the DDS horns to outperform the 2380, but I've not heard any of them yet. Price new is about the same.


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