That K-400 Washer

[Deang]

True or False:

The washer that Klipsch uses between the K-400/401 is part of the transition between the K-55 and the horn (since the K-55 is not a true 1" driver).

Thanks,

D

[jimjimbo]

I would say that is true, as the washer center orifice is definitely smaller than the outgoing driver orifice.

[ricktate]

Well when i could see the edge of the washer sticking into horn i thought i would try an O-Ring and it seems to work better. I had to put a very small amout of petroleum jelly on the ring to keep it from binding up when screwing the driver on. I also put a very small drop of crazy glue on the ring to hold it to driver in the right position. Now the throat is clear of obstructions.

[Quiet_Hollow]

False.

 

1/4 wavelength at 6000 Hz is still better than 1/2 an inch. IOW, it would have to protrude a lot to be a problem.

 

The factory gasket compresses down to almost nothing along the length of the fitting.

 

How much of, or little, the gasket may get in the way of the throat is a matter of splitting hairs within the horn's pass band.

 

Ensuring that it forms no extra cavities along the joint interface instead, like a typical o-ring would, and seals it airtight are the most important factors at play.

[Deang]

Excellent. Thanks!

[djk]

"1/4 wavelength at 6000 Hz is still better than 1/2 an inch. IOW, it would have to protrude a lot to be a problem."

 

While that sounds good in theory, in actual use it can be a real problem.

 

Altec had an app note that showed real problems with small bumps (in the throat area).

 

Some horns I made almost 30 years ago were declared to have a 'piezo-like' problem around 3-4KHz that was found to be a tiny (grain of sand sized) bump in the fiberglass in the throat area.

 

After correcting the problem:" The highs are MOST interesting in the fact that they (if
crossed over at 3.5-4K) DO measure ruler-flat all the way up to 18+
Khz.  There are NO nasty resonances or 20db peaks and valleys, etc,
which AT FIRST makes you THINK that there is "no" high end - it is so
smooth, unassuming and non-zingy it takes a bit of getting used to.
There is NOT a lack of HF though, the highs are completely smooth and
hyper-extended and incredibly DETAILED."

 

(the driver was the Community VHF-100)

 

"The mids are so smooth and perfect that
nothing can be said about them, they are completely transparent."

 

(M-200 on SH-494)

 

"The napkin drawings have been converted into physical reality
(Community-based loudspeakers).  They sound quite smooth, however
there is still a little (1 or 2 db peak) problem at 3-4 KHz, which I
think is attributable the the HORN (we are using the Kleitsch 1"
throat horns - the little Altec horns are EVEN WORSE - they have a
10db peak centered around 3.5KHz)."

 

"We installed the system at the Jazz Club and it sounds glorious!  The
midrange and high-end DETAIL and "realness" is uncanny (even WITH the
CRAPPY Ramsa mixer in the signal path - we are going to get RID of it
and use something else - it RUINS the sound).  We were sitting there
at their opening party last night for awhile - they were playing
CD's...  The sound was completely smooth and natural EVERYWHERE in the
room.  Recordings with well-recorded drums sounded like there was a
real drumset in the room - the speakers are extreemly ARTICULATE in
the midrange  and highs.  Every time I listen to them the word
"seductive" comes to mind.  Even the low end has a SEDUCTIVE
SSMMOOOTTTHHH natural sound!"

 

(double 15 Eminence per side)

 

So, a tiny 'bump' in the throat that was barely measurable (1 or 2dB peak) gave the system a 'piezo-like' quality that vanished after correction.

 

Amps: Crown D60, D150, DC300A .  Crossover:TDM 24CX-3 (with 38hz high Q filter).

Edited July 6, 2016 by djk

[Marvel]

Dennis, the throats on my nice k400 castings are only 11/16, while my EV drivers are 7/8. Would it make sense to hve these match? I can get them opened up...

Bruce

[Karsoncookie]

Dennis, the throats on my nice k400 castings are only 11/16, while my EV drivers are 7/8. Would it make sense to hve these match? I can get them opened up...

Bruce

 

So that results in a 3/32 step.

 

Very interesting detailed query, would be great if able to get an answer based on non subjective facts.

 

Maybe answered by djk above, I'm not educated enough on this stuff  to follow it.

 

 

The k400 can certainly be reamed out, if not by hand, accurately by many machine shops.

 

I would guess $100 / pair would about do it.

 

But you still MAY end up with some step up like on one side, and step down on opposite side, If the original hole in casting was not totally truly centered on the horn body.

 

Like you won't know, till you screw the driver on, how smooth and equal on ALL sides. Not "Offset".

 

Unless you were willing to pay more to Machinist labor and thinking time to consider that.

 

A gasket with a specific ID would need to be found/ made.

 

 

How much does it really matter?

 

PWK, by design, or default, seemed to have let the mismatch AND the casting imperfections slide, as evidenced by "flash" in many of them.

 

 

  Lars

Edited July 6, 2016 by Karsoncookie

[wvu80]

  The washer that Klipsch uses between the K-400/401 is part of the transition between the K-55 and the horn (since the K-55 is not a true 1" driver).

 

True or False:

 

I vote False.  The washer would flutter, it should be an exact fit.

 

How'd I do on the quiz? 

[Marvel]

Lars, I think it would make a difference.

That was then, this is now... Maybe someone will measure their k-401 throats for us. I would be willing to bet the newer horns are more consistant, and perhaps more accurate.

Edited July 6, 2016 by Marvel

[Karsoncookie]

I guess It depends on the source data used and execution for the 401 mold.

 

From a Klipsch print, or from measuring a few 400's.

 

For that matter, do all " 1" " screw on drivers have the same id size? Or at least, all mfgr used as "55's" ??

 

 

I would think the 401 were made over a fiberglass core plug  mold that ended up with more consistent ID's.

 

Not degrading through uses,  hence not through wear continuously  narrowing the throat ID as another previous thread's posting explained w the 400 molds.

 

Lars

Edited July 6, 2016 by Karsoncookie

[mungkiman]

Great point, Lars.

[WMcD]

djk,

 

Do you have a copy of that Altec app note or can you point me to a source?   I'd love to read it.  I have searched around the Internet with no success.

 

Thanks,

 

WMcD

Edited July 7, 2016 by WMcD