JBL 2404's instead of K77

[Q-Man]

I used to be able to right click on an avator photo and open it to view a larger image. I just tried it and I can't do it anymore. I don't know if it is my computer, or the new Klipsch Forum acting up.

[Marvel]

It's the forum sofware. It resizes and won't show the original pic. At least it makes all the avatars load faster.

Bruce

[Q-Man]

Thanks Marvel,

The new 2404H tweeters are called 2404H-1, not the letter I like I posted above.

I got them at Performance Audio www.performanceaudio.com ask for Zach. The price was $250.00 each. I first tried to buy them from a local dealer, but they wouldn't answer my emails.

[djk]

The 2404H has the 2402 diaphragm, the -1 has the 2405 diaphragam.

The -1 is smoother and goes higher, but must be crossed steeper (18dB or higher).

[Q-Man]

The 2404H has the 2402 diaphragm, the -1 has the 2405 diaphragam.

The -1 is smoother and goes higher, but must be crossed steeper (18dB or higher).

If that is true, I may end up ordering two 2402 diaphragms so I don't have to mess with the networks again. On the other hand, smoother sounds good.

I was told that the parts were the same, I have to call them.

[jorjen]

If you go with the Trachorn and could bump the xover point up to say 7000, I might be inclined to give the 077/2405 a shot.

The Trachorn should go to 7 alright, should'nt it?

[Q-Man]

I just spoke to John with JBL tech. support and he said that the 2404H and the 2404H-1 both use the same diaphragm. The diaphragm # is D16R-2405.

His number (818) 895-8157.

[Deang]

I wouldn't use anything but a 300Hz or below midrange horn and driver with a Klipschorn. The bass horn drops off fast over 300Hz.

BS

[DrWho]

"It has also been my impression that the 2404 is better in the lower

ranges of its passband than in the higher regions..."

Other way around. It is better up top then down low.

Ummm....it's one thing if you had different impressions, but I just

wanted to clarify that I didn't reverse what I described I heard. And

I'm pretty sure you're not telling me what I was hearing.

But ya to help quantify, I never felt the 2404 did very well in the top octave of its

response (like 10kHz+). Just for kicks I looked up the specs and there

might be some indication as to why (early drop off and a few random

dips in the response...though frequency response isn't everything):

http://www.jblpro.com/pages/pub/components/2404.pdf

(Maybe it's my young ears...)

Btw, you guys doing custom stuff really need to invest in some

measuring equipment. For what you're spending on your systems, $100 or

even $300 for an RTA or ETF isn't that much and is asbolutely required

for calibration.

[DrWho]

Dean, how was the measurement arrived at?

Tis' quite nasty if you ask me and clearly shows rolling off at 300Hz?

[sfogg]

The way I read it it didn't sound like you had ever heard one and were just going by what others have said. That is what I was responding to. Sorry I read it wrong.

"I never felt the 2404 did very well in the top octave of its response (like 10kHz+). Just for kicks I looked up the specs and there might be some indication as to why (early drop off and a few random dips in the response...though frequency response isn't everything):"

It does very well above 10kHz. It does less well below about 8kHz... less pattern control and a more uneven response. If yours aren't going up above 10kHz well you might want to check out the diaphragms they are probably work hardened and need to be replaced.

You can also check Al's measurement of the 2404 here:

http://forums.klipsch.com/forums/thread/569100.aspx

"$100 or even $300 for an RTA or ETF isn't that much and is asbolutely required for calibration."

Agreed, I have numerous measurement tools. And something like RoomEQ Wizard is freeware. When you have this there is no need to 'look up the specs.'

Shawn

[Deang]

Who,

That's the raw response of the K-horn bass bin as shown in the P. Klipsch/ R. Delgado JAES Paper on the Jubilee. Don't make the same mistake everyone else does and stare at those two peaks until your eyes cross. They are peaks, ignore them. Look at the response from the 104dB perspective. Still ragged, yes, but clearly she has decent output to 450Hz. When you add a network, it's a bit better. The later series filters lift the sagging response @ 75Hz, and in the AK-4 there is a trap that brings down those peaks. At any rate, sure, a nice big driver/horn combo that allows for a lower cut-off is certainly beneficial -- but not necessary.

If you think that response looks rough, you should see it from end to end. However, like I told Bob on the phone the other day while discussing the K-55-V and K-55-M -- when you get right down to it we don't really listen to these speakers for their smooth FR.

[sunnysal]

my take on bass bin is 35-500hz without problems, that seems to more or less match the "-5" points on the graphic posted. 2404h looks great to me 4k-17k...when I did my homemade, ratshack (yes adjusted with the famous table) testing that is exactly what I got. no RTA, FFL, BMW, etc. ya'know but that is what I hear/measure in my room.

the 2404H sounds great to my ears, a significant improvment over k77, it's a keeper.

tony

[sunnysal]

<?xml:namespace prefix = v ns = "urn:schemas-microsoft-com:vml" />curve 2404h

<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

[Coytee]

So, if they're discontinuing this, and original diaphrams are available, should one get a spare?

I'm sure mine have been replaced and likely with aftermarket, though I dont "know" that.

[Deang]

I'm interested regarding the specifics related to the differences between the two.

[djk]

"he said that the 2404H and the 2404H-1 both use the same diaphragm"

http://www.jblproservice.com/pdf/Theatre%20Series/46120K.pdf

That guy at JBL probably hasn't worked there for very long. The D8R075 (orig.) is the diaphragm for the 2402.

• Posted by

djk ( M ) on July 13, 2004 at 02:37:29

In Reply to: Re: "spitty" or "harsh" posted by weltersys on July 12, 2004 at 23:25:11:

The 2402 diaphragm is twice as thick as the 2405, and has a peak at 12.8Khz, but handles more power for lower crossover points.

One reason this tweeter has the rep being "spitty" or "harsh" is that most of them rub.

Shimming both the inner and outer horn sections while using a spectrum analyzer takes care of the problem. The shims needed are in the range of 0.002"~0.010".

The diaphragm is normally left in place, make sure it doesn't rub in the gap, they usually don't (with real JBL parts).

The shims go between the diaphragm and the phase plug and outer horn assembley. I cut shims from masking tape using a pair of wire cutters, and stick them on top of the JBL shims (which are stamped aluminum spacer rings). Use non-magnetic tweezers for handling the shims.

I use 3M masking tape, its thinner and has less adhesive to squish. Usually it takes two layers for the right thickness. I shim both the phase plug and the outer horn in four places so they don't rock (a total of eight places).

I've seen 2405s go from ±5dB to ±1dB over their range.

The ones that rub sure play a lot louder (if you can stand the sound)!

[Q-Man]

I may not know unless I take them apart.

I think the guy that I spoke to was old school. He told me alot more then I wanted to know.

Twenty years ago we did this, ten years ago we did that, today they are the same. He must have talked about every part that is in the tweeter and why things changed. Then I had to hear about their new designs and why things are changing now.

Later in the day I called the parts department and was also told that they use the same diaphragm.

[JJkizak]

So if I replace the K77's with JBL 2404's in the K-horns and the center channel Cornwall with Dean crossovers, will it work?

JJK

[DrWho]

It does very well above 10kHz. It does less well below about 8kHz...

less pattern control and a more uneven response. If yours aren't going

up above 10kHz well you might want to check out the diaphragms they are

probably work hardened and need to be replaced.

It wasn't that they didn't go up that high...they just sounded more distorted at the higher frequencies than the lower frequencies (talking small amounts here). Perhaps there was that rubbing issue? Who knows. (they weren't my speakers so it's not like I can go back and find out). It wasn't a huge deal (definetly not like a rubbing VC), I just felt it was slightly better in the lower frequencies...enough to make me want to consider a better tweeter.