Article on the K-Horn and Interview

[WMcD]

For your weekend reading.

Gil

gilpaper

[WMcD]

I put this on the second page of the thread because the first page seems to often ignore the attachement.

Gil

VTV K-Horn.pdf

[IndyKlipschFan]

Great reading Gil, I just finished it.

Don't let the tube amp guys read it, they might get mad arguing!!

I love how Paul was never really stuck on himself. A true Dale Canegie kinda guy!!

Bell labs seemed to have such a strong place in Hi Fi History, I wonder why we do not see any speakers or amps from them today?

[D-MAN]

Bell labs was never really in the manufacturing end of things. They were the research entity of Ma Bell. Western Electric was the manufacturing end of the Bell company. Western Electric gave birth to Sandia Labs, which, of course, is big in the defense industry.

DM

[edwinr]

Thanks, Gil. I just printed the article off. Sheds a bit of light on a few areas I was unsure of.

[WMcD]

I'll bump up this old post of mine. The reason for the bump is that there are questions coming up about attenuating the midrange by resetting transformer taps or adding L-pads.

This article from Vacuum Tube Valley suggests the use of what we call a P-trap to cure what it calls a "shouty" horn. It filters out the program sent to the midrange over 6000 Hz. The trap (or "tank" circuit) is a cheap and simple addition.

We have seen the various plots showing that all (or just about all) of the midrange drivers used in the Heritage have some output up there. I've recently seen an EV driver in the 1800 series which also has it.

The Heyser review of the K-Horn states he (Heyser) thinks there is something going on in the crossover region of the tweeter. Maybe what he heard is actually this output by the mid in the tweeter region.

Gil

[soundbound]

Thank you Gil. A great article. I'm sure glad you bumped this one!

[colterphoto1]

Thanks for the bump Gil. I'd never read those articles. The second one does make note of the 9 Khz glitch and horn dampening.

[DrWho]

The second one does make note of the 9 Khz glitch and horn dampening.

I think that was something suggested and performed by the authors of the article - not the words of PWK. Not that it really matters, but just thought I'd point it out.

[djk]

"The Heyser review of the K-Horn states he (Heyser) thinks there is something going on in the crossover region of the tweeter. Maybe what he heard is actually this output by the mid in the tweeter region."

The pair reviewed by Heyser had the K55M, which does not have the peak at 9Khz.

The version he did review does have the elliptical filter on the tweeter. Removing it really smooths out the character of the tweeter.

[WMcD]

Thanks for the info, djk.

I've been trying to build a grand theory that the output above 6 kHz is what makes things shouty, and that various filter designs are good, or bad, because they suppress it, or not.

I'm being a bit niggly on this; but such are the worries of nigglers. Do you have any sound curves which show the -M does not have this type of output? We may have to dig up Bob C's curves.

It is interesting to me that there is a Dope from Hope which has curves showing that the dual path phase plug on the Atlas has better performance in the 4 kHz to 6 kHz region on a horn than the regular Atlas. (This is identified by push-on versus solder on terminals.)

But it shows they both have the output above 6 kHz, shifted a little bit.

Is the -M different in this aspect of output?

Also, I've not seen any description of the phase plug of the -M. Does anyone know whether it is a one-piece?

Best,

Gi

[mikebse2a3]

Thanks for the info, djk.

I've been trying to build a grand theory that the output above 6 kHz is what makes things shouty, and that various filter designs are good, or bad, because they suppress it, or not.

I'm being a bit niggly on this; but such are the worries of nigglers. Do you have any sound curves which show the -M does not have this type of output? We may have to dig up Bob C's curves.

It is interesting to me that there is a Dope from Hope which has curves showing that the dual path phase plug on the Atlas has better performance in the 4 kHz to 6 kHz region on a horn than the regular Atlas. (This is identified by push-on versus solder on terminals.)

But it shows they both have the output above 6 kHz, shifted a little bit.

Is the -M different in this aspect of output?

Also, I've not seen any description of the phase plug of the -M. Does anyone know whether it is a one-piece?

Best,

Gi

Gil you can look at this thread if you haven't already were I did some test with the ETF TEST PROGRAM that shows the various K55 drivers responses.

http://forums.klipsch.com/forums/1/735455/ShowThread.aspx

Also here is an internal shot of the K-55-M

mike tn

[BS Button]

The second one does make note of the 9 Khz glitch and horn dampening.

I think that was something suggested and performed by the authors of the article - not the words of PWK. Not that it really matters, but just thought I'd point it out.

Very astute pick up there Doc.

[BEC]

Gil,

Here is the thread with the tests I did.

http://forums.klipsch.com/forums/thread/772922.aspx

Bob

[colterphoto1]

The second one does make note of the 9 Khz glitch and horn dampening.

I think that was something suggested and performed by the authors of the article - not the words of PWK. Not that it really matters, but just thought I'd point it out.

Very astute pick up there Doc.

I knew that. I was just pointing out that the Forum had more than likely not 'invented' those mods. I never assumed that PWK made those statements.

[WMcD]

I was a bit surprised to read DJK saying that the K-55-M doesn't have the glitch.

Looking at BEC's data, it seems that it does. Arguably, it is the worst of the drivers tested in that the glitch goes to a higher amplitude than the others.

OTOH, BEC's measurments show the Atlas with two piece phase plug has no glitch. This is contrary to the DfH where the one piece and two piece are compared. They both glitch.

Thank you everyone for providing more data. I has seen a similar cross section, for example, and wondered whether it is the -M.

For now, my theory that the glitch is a major issue remains safe.

Next question for thought. What is causing the glitch? Diaphragm break up?

Gil

[WMcD]

Please let me point out that I'm not taking a strong stand on DJK's observation or Bob C.'s data. And I certainly don't mean to insult anyone. Maybe there are variations in units.

Gil

[BEC]

From back in 2005, we have this from TBrennen and reply by Good2BHome.

----------------
On 4/16/2005 10:56:27 AM TBrennan wrote:

The fella that came up with the P-Trap never claimed all Atlas drivers had the peak or that all should have a P-Trap. SOME of the drivers he tested had the peak, SOME.

The fella thinks that those who have a particularly fierce speaker should try the trap. If you think your speaker sounds fine then leave it alone.
----------------

To compliment the above:

I had an extended conversation with the P-Trap inventor (over wine and cheese), within the last year. He said about 20-25% of the "push-terminal" Atlas K-55 drivers exhibited the problem. The problem is not present in the "solder-lug" K-55s. These began shipping after March 24, 1980 per "Dope from Hope" # 19-1.

Mike

[WMcD]

Well, maybe there are production variations. And "none" really means 1 percent. It could be. Smile.

I hope the graph from the DfH shows up below, it is snapshot from a .pdf file I got off the forum.

All I can say is that that we have a lot of different data on the issue.

If a fraction of the one piece phase plug Atlas have the problem,this DfH happened to pick up on that small fraction. If none (or maybe 1 percent) of the two piece have it, then this DfH picked up the 1 percent. Heck, there could be 1 percent rather than none. And Bob's test shows a very low glitch.

If none of the -Ms has a problem, maybe that is actually 1 percent and Bob C just happened to have one of those 1 percent.

- - - -

Maybe these production variations account for the various reports we get from people as far as there being a shouty problem, or none.

Gil

[DrWho]

Next question for thought. What is causing the glitch? Diaphragm break up?

I believe it was Roy who mentioned that it had something to do with the phase plug - perhaps a standing wave of some kind?