altec/bms project help needed!

[stuck.wilson]

alright.. well.. maybe not NEEDED.. but i've been thinking, and i know similar projects have been done. Here's the skinny!

I've got a two way system-- and thanks to the research of zilch and a little help from doc edgar, and a whole lot of others, plus a lot of listening and soldering.. my system's been running for over a year (hooray!) and sounding pretty good to me.. but i've been wondering WHY it sounds so doggone good, when no matter how i think it out, it doesn't seem to add up!

heres what i have going on-- i have a pair of altec 414b's in 614 cabs. the crossover on them is a second order bessel (approximately)-- with a 4 mH inductor, and an 11uF cap, which i approximate at about 700-800 hz.

on the top, i have a community fiberglass horn- approximately the same size as the box-- i believe it's a 500hz horn-- and here's the wierd part. to get it to sound RIGHT-- i've got 5uF in a first order filter, with a 2uF bypass on an lpad. if i'm not completely wrong on the math-- that puts me at something like 13-1400 hz (on average... it's a little wavy in there for the 4552). seems like a pretty big gap between drivers-- but to my ear-- it sums out nicely..

now, i know there's loads of proponents of filtering down the mids, but that's just not the way i've chosen to do it... but my question IS- hearing no really apparent peaks, and seeing none in my crude measurements-- would it appear as if this is a plausible solution?

i'm not opposed to regearing-- but THEORETICALLY speaking.. i wonder what the speaker building community would think!

thanks all!

[Zilch]

The first-order highpass knocks down the excess midrange of the compression driver/horn in the crossover region. It's the acoustic sum that counts, not the electrical one.

That's a trick Altec used in Valencia to mitigate 806A/811B "Shout," even with second-order. Calc or measure the voltage drives, and they don't add up; it shouldn't work from the textbook perspective.

See my Altec 806A/811B/N800-F measurements posted elsewhere in this forum.... :yes:

[stuck.wilson]

The first-order highpass knocks down the excess midrange of the compression driver/horn in the crossover region. It's the acoustic sum that counts, not the electrical one.

That's a trick Altec used in Valencia to mitigate 806A/811B "Shout," even with second-order. Calc or measure the voltage drives, and they don't add up; it shouldn't work from the textbook perspective.

See my Altec 806A/811B/N800-F measurements posted elsewhere in this forum.... :yes:

thanks zilch-

i can't understand WHY.. short of the fact that the 414's got SUCH a big peak around 1k, that the runout slope is mitigated by the bump-- and thusly 'starts' rolling off LATER than it'd seem by the math... which always seems kinda unreliable given the squirreliness of impedance curves!

i'll have a peek at the other post.

meanwhiles-- thanks again for the help from the valencia post of last year-- that seriously got me straight on a LOT of stuff about the drivers in play.. doc edgar gave me the other key with the asymmetrical idear, and together, it really did get me where i wanted to go!