Speaking of Midrange Control...

[D-MAN]

Now that it is public, if I fail I hope to be severly chastized.[:$]

Rick

Rick, you should know us by now - you will probably get severly chastized even if you succeed! SOP, you know. []

{edit} just thought of another very interesting point about the top-end of my speakers -

I've found that the driver/horn placement front-to-back on the cabinet is VERY IMPORTANT in getting it to "sound right" and produce a beleivable soundstage. Notice how far back the horn sits on the bass bin? That is where it HAS to be. Sort of unexpected, but quite true. I assume that it has to do with the higher crossover point (600Hz) and the extreme slope crossover that I'm using that makes it much more critical than perhaps a gentler slope at a lower point would be, I don't know. I only know that the horn placement is, well, more critical to the overall presentation than one would reasonably expect.

So Jubilee people TAKE NOTE!

I've yet to figure it out to my satisfaction, but apparently there is a phase relationship with the bass horn that seemingly gets ignored in other horn "applications". I have found it to be very important to the overall soundstage with imaging and depth being truly convincing. It doesn't really have much to do with the frequencies, per se. More of an imaging/depth/soundstage thing. I think its particularily important, being that these days, you've got to compete with the tall-and-skinny "British-sounding" speakers that image pretty well, IMO. These do it, too, with a wider, taller soundstage with an realistic dynamic range. Too bad they are so big, the ONLY drawback that I can see.

But that's physics for you!

Dana

[D-MAN]

I am thinking that PWK ran across this in his design of the K400 being that it is quite long by today's standards, and that he wanted a fixed cabinet position (and that fixes the horn too) on the top end.

I'm guessing that the diaphragm is very close to where mine end up when all the "adjusting" is over. That is something to think about with all these new shorter horns.

DM

[3dzapper]

DM, When I had my trachorns on the top of the Khorns testing them I had to reverse the connections on the K-55 to get the correct phasing. With them inside the top hat set back for the grill, they want the normal hook up. You are definately on to something.

Rick

[steamer]

Dana,

Great thread.Some interesting discoveries in your system.I am still looking hard at the BMS 4592 coax driver down the road.Right now I have the BMS 4552 1" in place of the 902's on the 511 horns.I am trying to get some impressions of the BMS driver vs. the Altec 902.The 902 definately holds its own everywhere except in the efficiency area.BMS is 113db vs 106db for the 902.I have achieved my goal of higher eff and have all the attenuation out of my SS bass amps now.The tonal/level balance of the bass and highs are very close.

Greg

[sfogg]

"I've found that the driver/horn placement front-to-back on the cabinet

is VERY IMPORTANT in getting it to "sound right" and produce a

beleivable soundstage."

Try the old Altec trick for setting that up.

Invert the phase to your BMS driver.

Play a test tone that is at your crossover frequency. (600hz?, not pink noise.. a single sine at the crossover point)

Put a SPL meter at your listening position.

Move the horn forward/backwards till you find the point that has the

lowest SPL measured at the listening position. You are looking for

greatest cancelation where the drivers are closest to being 180 degrees

out of phase.

Invert the phase to the BMS driver again which would put it back in phase with the bass horn.

Shawn

[D-MAN]

Rick, I take it that you have not received my email?

I'll try again, but I don't trust this new fangled forum!

Dana

[3dzapper]

Nothing Dana. Try a PM on this site. I PM'ed my email address.

Rick