All around best 8-ohm substitute for K-33?

[Tom Mobley]

D-man,

Thanks very much for for taking time to write up that very informative

post. Lots of stuff there. I'll be looking that over and

comparing the drivers I looked at.

[D-MAN]

Tom, for the money, the Madisound driver is quite the bargain for reflex use.

I haven't tried one in a horn because of its rather high Fs although the rest of its specs look good for that too.

DM

[DrWho]

It remains interesting to me that the K33E would NOT be chosen for the horn by its T/S parameters! There is a great deal of leeway here!

This simply shows that whatever model you're using isn't accurate to real life...

...or the other conlcusion is that the khorn isn't all that it's made out to be []

[D-MAN]

Tell that to Keele!

But seriously, it is quite true, anyone who runs the numbers on the K33E will agree. The why it works as good as it does - and where THAT comes from is not in any horn-model that I know of!

However, it has become apparent to me that the Khorn/K33E combination is so intertwined that the two are inseparable and either one separately will not perform to the same degree in other combinations. That's my opinion.

I've gone the long way around to arrive at that, but I'm convinced now.

DM

[DrWho]

WinISD crashed on me, but I went through and modelled every 15" driver

included with the program (except the car audio brands) in their

corresponding optimized cabinets and tunings (yes I was bored!) []

There were a few drivers that stuck out: the K-33, the Magnum, and the

Kappa. The kappa has the highest sensitivity, but the lowest SPL

capabilities. The Magnum dug the lowest of the 3 and played the

loudest, but had the lowest sensitivity. The K-33 was right in the

middle...digging lower than the Kappa and going louder, but lower

sensitivity.

None of the other drivers dug lower than the Magnum and none of them

had a higher sensitivity than the kappa. There were a few that went

louder (like the eminence kilomax), but their F3's were very high. Of

these drivers the JBL2226 would be a real contender....according to the

specs at least. I have never been real fond of its real life

performance in the mid range frequencies.

Then there were a lot of drivers that didn't go flat above 400Hz so I

ignored them (drivers like the titanic, tempest, tumult, etc

etc...."subwoofer drivers")

It was interesting because most all of the 15" drivers wanted to be in

a cabinet anywhere between 4 to 12 cubic feet with tuning points in the

35-50Hz region.

Drivers in the smaller cabinets tended to exhibit shorter group delay,

but if the response of a particular driver dug down further, the group

delay was still shorter in the frequency range where both drivers were

flat, but the extended response exhibited much higher peaks. Ya, it's

hard to put in words but you see it so easily on the graph.

It was also interesting because every single impedance graph was very very similar (same shapes and close in value).

Anyways, all this to say....the K-33 as a direct radiator was definetly

in the top 3 out of many dozens of drivers. And coming in at a price of

$150 we're talking huge bang for the buck.

[BEC]

Tom Mobley

You have a PM.

Bob Crites

[D-MAN]

DrWho, that is a suprizing result to me.

I will let you know what I think of the K33E in a ported horn application hopefully very soon. Since the cabinet is specifically made for it, I would think that it will be a fine match, with its famous horn and reflex pedigree.

DM

[Tom Mobley]

Thanks Bob.

And thanks to all the guys who posted solid info in this thread, very helpful.

[TBrennan]

When considering direct-radiating 15s one must consider the upper bass and midrange performence as well as that of the lower bass. Personally I think there are no better sounding 15s than the Altec 515B and 416 models, not because of their lower bass but because of their superb upper bass and midrange. Were I considering a Cornscala type speaker and didn't want to use the K-33 the Altecs would be the way to go. Actually I'd never consider the K-33 as a direct-radiator in a DIY speaker to start with, if I already had them I'd use them but I'd never use them with a clean sheet of paper.

[Klipschguy]

How would a Altec 416 model in a Cornwall cabinet? I'd love to know. Qts is pretty low (about .27, if memory serves me).

Andy

[DrWho]

Bummer the altec requires a 12 cubic foot cabinet and is more expensive.

Here is a site with the T/S parameters:

http://alteclansingunofficial.nlenet.net/Thiele-Small.html

[D-MAN]

Tom Brennan mentions a fine speaker. I passed on the Iconic 515 ONLY because of the price. It is a fine T/S match to the horn (Khorn too) but I thought the Fs was too high for my taste. In a reflex cab, that would be a different story!

If I was going whole-hog on a no-holds-barred implementation, certainly an Iconic/Altec 515 would be a great choice. One of the last great horn/reflex drivers (the A7 is no slouch).

DM

[sfogg]

DM,

"I passed on the Iconic 515 ONLY because of the price."

How much are they going for new now?

" It is a fine T/S match to the horn (Khorn too"

Wouldn't fit in a K'Horn would it? I thought the Iconic 515 is a 16" frame driver.

From an earlier post....

" had a pair of Eminence Kappa 15LF's (used to be $90 ea) which were totally kick-butt drivers - they would change your heartbeat at 30 watts! However: they are sensitivity rated at 99db, though, so I could not get my high-end to match them, so I bailed on them for horn use. "

According to the Eminence info the Kappa 15LF is more like 96dB. The Kappa 15 is a couple of dB more sensitive.

Did you run either of these horn loaded? What horn?

Woofers being too sensitive isn't a problem bi/tri-amping.

Shawn

[jwc]

Guys, You all have mentioned great woofer options for all different type of applications.

In Tom's first post, he was looking for a K33 substitute in a Cornwall like cabinet. There are some great woofers out there for a DIY project but he might want a predictable sound. The magnums and the Altecs may sound like crap in a Cornwall cabinet. You could argue for or against it. But no-one has heard them in that application (or have they?).

If I were to chose a woofer that is similar to the K33 but closer to 8 ohms, I would chose one of the Delta series. They are in about the same price range as a K33 and have similar response curves to the K33 in a Cornwall cabinet. No I haven't heard them...so I won't be able to respond to a challenge.

Now if I were to try an all new "sound" and chose a vented cabinet volume and port de novo, I would chose the Magnum or the Omega series from Eminence.

jc

[Tom Mobley]

Hmpf. might lead to the interesting concept of padding down a woofer....

[Klipschguy]

Glancing at the 4168B specs, it looks like it would do fine in a Cornwall cabinet? Anyone wanna plot a graph?

Andy

[D-MAN]

The Iconic 165 dealer cost > $279 end user $418.50 MSRP $629

164 (which will work in a short horn or bass reflex) same price as above.

Very nice drivers, though. I talked with Iconic about them. They have some new models coming out too.

With the exception (mine) of the Fs being a little high (40Hz) for the horn.

The Khorn baffle can take a 16" wide frame for certain. - It's the depth that'll kill ya and the size of the access cutout. I will check on that.

T/S-wise, it is very good, although I would think about the 200w version vs. the 75 watt (515/165) version, being a better match to a 78" throat.

Eminence has changed the line; I had the Kappa 15LF (8 Ohm) which is/was rated at 99db. However, if you look at the Eminence sensitivity pdf, it greatly depends on what frequency one is talking about. Anyrate, they are gone now, so I cannot double-check but I'm possitive they were the Kapp 15LF version. But they were definitely TOO efficient in the horn (also they had a 39Hz Fs which was a little high). At the time their price was something like new $89 each, which was quite a bargain. Not anymore, now that I looked at partsexpress.

I only have horns to use (so far), and all of my "testing" is in the horns.
However, the Kappa's kicked in the horns, aside from the deficiencies that I mentioned, they would make (in my estimation anyway), a fine pair of reflex drivers. If I could get a pair of speakers that did what they did AND go as low as the K33E, I'd have a wonder-speaker!

DM

[D-MAN]

When you horn load a driver, its impedance goes up. In the case of the K-33 -- it almost doubles. At any rate, it's spec'd out as a 4 ohm driver, and should probably be treated as such in a straight up design.

The K33E is about 6 Ohms in the horn for crossover purposes. In a reflex application, I would figure its rated value (4 Ohms or so) basically what Dean said.

In the case of an 8 Ohm driver (if there is such a thing), it ends up about 10 or 12 Ohms, as an example. That value changes with frequency, but the frequency range we are talking about in a bass horn is restricted enough that an average impedance can be "chosen".

The point I am making, I guess, is that it doesn't double its impedance in the horn and what it actually does do is also a little up in the air, too.

Best to actually test "in horn".

I ended up choosing a reactive little bugger that flies all over the place, but THAT might be the very reason that I preferred it, I don't know.

DM

Impedance; open throat follows.

[Tom Mobley]

D-MAN,

Thanks again for your posts. It takes time to write this stuff out and I appreciate you taking that time.

[D-MAN]

Tom, happy to do it. I appologize for being so horn-centric on this, I know that your question was concerned with reflex drivers.

DM