Article: Progress in Klipsch Speakers 1948

[WMcD]

I had posted this several years ago in the middle of a long thread.

It deserves posting as part of my occasional Article postings.

There is lots of interesting information.

PWK describes the adoption of the 15 inch driver which does not require the use of the rubber throat rapid flare.

We also see his quest for a driver with lower Fs. IMHO, this is reflected in the early K-33-E's (long after the K-3 mentioned in the article) which have a lower Fs than the "modern" K-33-E's. The modern one, IMHO is optimized for the Cornwall.

There are some comments out there that driver (in a box) resonance should be placed at Fc of the horn. PWK is saying something different. The finite length horn presents some finite acoustic load below Fc. But in my view, the driver in a box does not have much output below the resonance of the speaker in a box, and the box is forcing up the resonance freq. Therefore he is looking for the most floppy driver (low Fs). Also he redesigned the back chamber to find as much volume (in cubic inches -- not sound pressure) as possible,

PWK also describes the testing of the back chamber for an airtight condition. That shows up in the EV plans.

Your weekend reading.

Wm McD

Progress in Klipsch Speakers.pdf

Progress in Klipsch Speakers.pdf

[Chris A]

Thanks! Nice reading...

[greg928gts]

Perhaps the most important observation of the author:

Wife-trouble should now arise only from considerations other than appearance!

Great stuff.

Greg

[seti]

Very cool. I love the khorn pic.Thanks for posting.

[ZAKO]

The outer surround DBP treatment gave a 2:1 improvement in compliance of the woofer,,,,But not all woofer models responded to this treatment,,,It would be interesting to now recover some of those earley woofers to find out What the compliance now measures..

[boom3]

IIRC, the standard woofer was a Stephens (Stephans?). I think some are still extant, probably in the Klipsch museum. I wonder what kind of oil PWK used to increase compliance.

About 31 years ago, I was looking over some woofer samples from CTS Paducah. I was surprised at the variation in Fs between samples (TS parameters were just becoming known). The engineer I was working with laughed and said that was the norm.

[Chris A]

There is lots of interesting information.

It's interesting that PWK's apparent design criterion was reproducing the 32' stops of pipe organs: "Technologically, the increased wavelength-handling capacity of the late-model woofers can be appreciated only with a few organ recordings or by users who apply the speaker to electric organ outputs."

That's interesting because I recently invested in horn-loaded subs to restore the remaining octave below 32 Hz (16 Hz). That bottom octave does contain a great deal of information/presence missing from just the standard Khorn's output.

It's also interesting for me personally since I originally acquired Khorns in order to accurately reproduce my organ recordings (being the son of an organist). My wife...who didn't grow up on a steady diet of Bach and Buxtehude...usually does her errands when I put on Bach. [H]

Chris

[garyrc]

We also see his quest for a driver with lower Fs. IMHO, this is reflected in the early K-33-E's (long after the K-3 mentioned in the article) which have a lower Fs than the "modern" K-33-E's. The modern one, IMHO is optimized for the Cornwall.

Do you know what the years "early" and "modern" are bound by for the K-33E? Two of mine (in Khorns) are from 1982, and one (in a Belle Klipsch) is from 2005. Would these be early or modern? I'm not clear on what kind of difference this would make in the sound.

[WMcD]

Gary, I don't have any hard information.

My guess is that the K-Horn might not have been very sensitive to the parameters, though obviously PWK was looking for low Fs.

My other guess is that the CW required a driver with a specific parameters and perhaps that is when the characteristics got firmly set and required good QC..

Wm McD

[garyrc]

It's interesting that PWK's apparent design criterion was reproducing the 32' stops of pipe organs: "Technologically, the increased wavelength-handling capacity of the late-model woofers can be appreciated only with a few organ recordings or by users who apply the speaker to electric organ outputs."

That's interesting because I recently invested in horn-loaded subs to restore the remaining octave below 32 Hz (16 Hz). That bottom octave does contain a great deal of information/presence missing from just the standard Khorn's output.

It's also interesting for me personally since I originally acquired Khorns in order to accurately reproduce my organ recordings (being the son of an organist). My wife...who didn't grow up on a steady diet of Bach and Buxtehude...usually does her errands when I put on Bach.

Chris

Isn't it true that most church or hall pipe organs don't go below 32 Hz, while some theater organs go to 16 Hz?

OR are there lower frequency "beats" below 32 Hz generated by church organs? I don't know much about this, but I thought I heard that "beats" are only generated by two simeltaneounsly sounding sources, like to bass viols playing together ??? There was an old Scientific American article called "Binaural Beats in the Brain" that may have indicated (the article appeared about 30 years ago!) that when using headphones, with a different frequency being sent to each ear (just a few Hz different from one another) the 'beats" can be formed in your brain with no acoustical connection ... if it doesn't happen in the room, it will happen in your brain??? Of course, I could have halucinated all this.

[Chris A]

Isn't it true that most church or hall pipe organs don't go below 32 Hz, while some theater organs go to 16 Hz?

Most of the instruments that I'm familiar with have 32' Bourdon stops, which are 16.4 Hz fundamentals, I believe. Sixty-four foot stops are 8.2 Hz fundamental frequency.

Beat frequencies are below the lowest frequency of two closely-matched frequencies.

Interesting discussion on "headphone beating". I would assume that it would work. There were lots of good SA articles back then.

Chris