Al K's Extreeeeeeeeeeeeeeeeeeeeeeeeeeeme Slope Crossovers!!!

[laatsch55]

It's the enclosure Joe...PWK was very explicit about that 400 number also..
The BMS-4592's were much more tolerant of 400hz but to my ear the DCM 50's are a little smoother. I'll take the tradeoff...

 

[Gibsonian]

I figured it was the low freq horn that was driving this. If you have a mic and some pink noise you could run the woofer only and examine the freq response. PWK the man but ya never know till ya look. Trust but verify is the translation of the Missouri show me slogan.

I can see why the DCM driver sounds much better, it has much better freq response down low. The BMS at 400 Hz it is down more than 10 dB. It doesn't look very good for a cross that low. On their spec sheet it shows a freq response of 300-7000 for 4592, but they don't even measure it there, it'd be more than 20 dB down. Curve stops at 400 hz and it appears to be about 14 dB down there. No bueno, ;marketing boys given too much leeway it seems here. I wouldn't cross the 4592 over at less than 700 Hz if I was to use that driver. DCM much better for your application, blow or no blow.

 

[laatsch55]

Thanks Scott. I never looked at the curves..glad to see my ears weren't lying to me!

 

[Gibsonian]

Seems those abused natural transducers of yours still working well!

 

[laatsch55]

That in itself is amazing. The music abuse doesn't hold a candle to the oilfield abuse of said transducers...I've been on a lot of noisy drilling rigs, workover rigs and water plants..

 

[mlucitt]

I wouldn't cross the 4592 over at less than 700 Hz if I was to use that driver.

I favor a crossover that transitions at 800Hz. That is a good balance between making the woofer work too hard and making the midrange work too hard.

 

[Gibsonian]

Understood. I protect my ears always now unless cranking. I don't wanr t

I favor a crossover that transitions at 800Hz. That is a good balance between making the woofer work too hard and making the midrange work too hard.

All depends on the woofer and the mids that you are working with. Lots a choices out there with far different capabilities

 

[laatsch55]

I always wanted to run just the Bass bins with a set of Martin Logans for the mids and highs...might get that done one of these days..

 

[mlucitt]

Understood. I protect my ears always now unless cranking. I don't wanr t


All depends on the woofer and the mids that you are working with. Lots a choices out there with far different capabilities

No, it's physics. It takes a certain amount of power to reproduce 50-500Hz, it takes more power to reproduce 50-800Hz and the woofer converts that increased power to heat. Likewise, if your midrange is reproducing 500-8000Hz and if your change that to 800-8000Hz, your midrange will sound better and last longer due to less cone/diaphragm excursion and less heat.

Yes, different drivers have different capabilities, but they all handle power the same way. You can control the amount of power presented to the driver (at a given wattage level) by changing the crossover frequency. Less bandwidth applied to the driver, less work the driver has to do.

At least that is what I was taught at JBL in Northridge, CA after they were bought by Harman International in 1969.

 

[laatsch55]

AND....EXTREME slope crossovers like these (96db/octave), are easier on the drivers...

 

[George S.]

No, it's physics. It takes a certain amount of power to reproduce 50-500Hz, it takes more power to reproduce 50-800Hz and the woofer converts that increased power to heat. Likewise, if your midrange is reproducing 500-8000Hz and if your change that to 800-8000Hz, your midrange will sound better and last longer due to less cone/diaphragm excursion and less heat.

Yes, different drivers have different capabilities, but they all handle power the same way. You can control the amount of power presented to the driver (at a given wattage level) by changing the crossover frequency. Less bandwidth applied to the driver, less work the driver has to do.

At least that is what I was taught at JBL in Northridge, CA after they were bought by Harman International in 1969.

No, it's physics. It takes a certain amount of power to reproduce 50-500Hz, it takes more power to reproduce 50-800Hz and the woofer converts that increased power to heat. Likewise, if your midrange is reproducing 500-8000Hz and if your change that to 800-8000Hz, your midrange will sound better and last longer due to less cone/diaphragm excursion and less heat.

Yes, different drivers have different capabilities, but they all handle power the same way. You can control the amount of power presented to the driver (at a given wattage level) by changing the crossover frequency. Less bandwidth applied to the driver, less work the driver has to do.

At least that is what I was taught at JBL in Northridge, CA after they were bought by Harman International in 1969.

Exactly! And that's why active electronic crossovers like the Minidsp and others are so popular. One can tailor the spectrum and slopes given to each driver or group of drivers.

 

[Gibsonian]

No, it's physics. It takes a certain amount of power to reproduce 50-500Hz, it takes more power to reproduce 50-800Hz and the woofer converts that increased power to heat. Likewise, if your midrange is reproducing 500-8000Hz and if your change that to 800-8000Hz, your midrange will sound better and last longer due to less cone/diaphragm excursion and less heat.

Yes, different drivers have different capabilities, but they all handle power the same way. You can control the amount of power presented to the driver (at a given wattage level) by changing the crossover frequency. Less bandwidth applied to the driver, less work the driver has to do.

At least that is what I was taught at JBL in Northridge, CA after they were bought by Harman International in 1969.

Yes it's physics as you say and the most importantly the physical properties of the drivers used determine where best to cross. I recently had a system with an AE 12" woofer for the mid, crossed from low freq driver at 200 Hz in a 3 way design. Sounded best there after much experimentation in the active triamp system and could handle all the power I could throw at it. Lee's Khorn's, 400 hz, JBL new L100's are crossing at 450 hz, Sonus Faber typically crosses at 250, JBL Jubal 1000Hz, Polk Audio L800 crosses at 370. JBL 4343 crosses at 300 Hz using a 10" mid. Two ways with domes have to cross at 2000 Hz or more so the tweeter can survive. If every design targeted 800 Hz we'd have a number of poorly engineered speakers imo. So I guess we'll have to agree to disagree.

 

[laatsch55]

This is turning into an interesting conversation..

 

[George S.]

And remember, when you use a active electronic crossover, it's placed before the amplifier. Therefore that spectrum "slice" your giving the amp is smaller than the whole "pie". Your amp runs more "efficient", as does the driver. And no energy is lost as heat as in a conventional crossover, with all the other problems a conventional crossover (most I don't understand) causes.
I really need to build 2 more WOPLs, and upgrade my Minidsp 2x4 to a 2x8. 1 WOPL each for subs, woofers, mids, tweeters. Now that would be the ultimate! Someday. Active crossovers tailored to each driver, fed by WOPLs, gosh what a system that would be! So pure, so efficient!

 

[George S.]

Oh crap, big problem, I need to get the New Green Deal Fairy to upgrade my house wiring first.

 

[mlucitt]

Yes it's physics as you say and the most importantly the physical properties of the drivers used determine where best to cross. I recently had a system with an AE 12" woofer for the mid, crossed from low freq driver at 200 Hz in a 3 way design. Sounded best there after much experimentation in the active triamp system and could handle all the power I could throw at it. Lee's Khorn's, 400 hz, JBL new L100's are crossing at 450 hz, Sonus Faber typically crosses at 250, JBL Jubal 1000Hz, Polk Audio L800 crosses at 370. JBL 4343 crosses at 300 Hz using a 10" mid. Two ways with domes have to cross at 2000 Hz or more so the tweeter can survive. If every design targeted 800 Hz we'd have a number of poorly engineered speakers imo. So I guess we'll have to agree to disagree.

My opinion of crossing at 800Hz assumed a two-way 8-Ohm conventional speaker system powered by one amplifier using a passive 6 or 12db/octave network. Of course, when you add bi-amping, tri-amping, active crossover networks, 4-Ohm drivers, and three-way or four-way speaker systems; crossover frequencies become more aligned to the individual components. I was discussing pure power, or energy, as it relates to the frequency spectrum. Just make sure your components can handle the 'power' at the crossover frequencies you are using and not an average of the bandwidth, say 200-2000Hz. What sounds good can be influenced by our ears inability to hear lower frequencies, and the heat in the voice coils is not related to what we can or cannot hear.

 

[laatsch55]

Mt woofs are 4 ohm, mids 8 ohms, tweets 8 ohm..

 

[premiumplus]

96dB/Octave?!? Don't you run into some notch or phasing problems with such extreme slopes?

What's the proper way to spec your cutoffs, do you have some overlap so that there isn't dropoff at the crossover frequency? I'm just trying to wrap my brain around how this is beneficial and why it wasn't done before. Never heard of it, sorry to say.

 

[laatsch55]

Dave, I thought there would be a notch at the crossovers too, doesn't work that way i guess...

 

[laatsch55]

Speaker surgery today. New diaphragms for the BMS 4592's ...