Will these woofers work in Khorns?

[BEC]

Edgar,

Which K-33E are you using in your test? The ones made before 1985 have an FS of around 27 hz. The ones after that are quite different with an FS of about 34 hz.

Bob

[Edgar]

Fs = 34.46 Hz

Vas = 10.65 cubic feet

Qts = 0.39

It looks like I'm using the post-1985 numbers

It has been quite a long time since I created that Hornresp model, and frankly I don't remember where I found all of the other parameters. I think that someone posted a complete set in a forum message a while back.

Greg

[BEC]

Edgar,

I did a test (assisted by John Warren) on two 1974 model K-33Es and compared the results to those for a new right out of the box K-33E a few years ago.

I have attached those results as a PDF to this post. Of course the 30 year old woofers I tested probably have some age related changes in them. You can see that they test somewhat different. Since we can't get any new 30 year old woofers, don't know how to do a better comparison.

Bob

TStest11.pdf

[Edgar]

Bob,

Except for Re (4.95 vs. 3.33), your measured "N1" numbers agree reasonably well with the numbers that I used.

Fs 35 vs 34.46

Qts 0.403 vs. 0.39

Vas 8.8 vs. 10.65

Greg

[greg928gts]

" It wouldn't affect the crossover points at all would it?" in an AA type network, because of duplexing nature of crossover networks, it would actually shift if you run numbers through a crossover calculator using the correct impedance, then re-run them using 8 ohms for the woofer, you'll get an approximate idea of the shift.

What about with the ALK ES networks? Any ideas what the 8 ohm woofer would do to the crossover points?

Greg

[JohnA]

" It wouldn't affect the crossover points at all would it?" in an AA type network, because of duplexing nature of crossover networks, it would actually shift if you run numbers through a crossover calculator using the correct impedance, then re-run them using 8 ohms for the woofer, you'll get an approximate idea of the shift.

What about with the ALK ES networks? Any ideas what the 8 ohm woofer would do to the crossover points?

Greg

The K-33 runs just over 6 ohms in the horns. The proposed woofers would run just over 8 ohms and that would raise the high pass filter on the woofer to about 550 Hz. Since the folded horn of the K-horn has trouble responding above 350 to 400 Hz, the actual effect on the crossover and the total reaponse shouldn't be too serious. Only testing will tell. The 1550 looks to be the better choice, to me, but, again, testing, testing, testing.

I don't trust listening tests for frequency response, just glaring errors in amplitude response. If your source material doesn't go below the open E on a bass, you'd never know if any of these woofers are better, or deficient.

[brsanko]

These precision devices drivers look to me to be some of the best horn drivers I've seen. Everyone keeps posting the 2.83 v response as if it told the whole story. If yo look at the max SPL of the design you'll see that these drivers put out signifigant output all the way down to 20hz and the impulse response is leaps and bound better than the other drivers listed. I know it's against some unwritten audiophile bible but these speakers have the ability so if you want lower bass use the EQ or even (gasp) turn up the bass knob!!