Did PWK Intend For Klipsch Speakers To Be Equalized ?

[seti]

I also find it interesting that PWK would pose for this picture with the Brook. Hint: it's under the record player...

The 4 knobs, left to right, are channel selection, bass, treble, and gain.

Nice pic of his Brook gear. I've been drooling since the first time I saw them.

[mungkiman]

Lee, here it is:

[stormin]

I also find it interesting that PWK posed for this picture with the Brook 12A3 (K1). Hint: it's under the record player...

The 4 knobs, left to right, are channel selection, bass, treble, and gain.

He sure has the bass cranked up in that photo.

[ClaudeJ1]

I also cannot believe that nobody brought up the 600 Electronic Crossovers for the KP-600s as this is a form of equalization that would have had to meet with Pauls approval.

Roger

I'm feeling ya there Roger

Well, since it's a rare and expsive 5-way modular PRO speaker from Klipsch, why would they? I belong to the same camp as you guys in liking the large format stuff for home (beyond Khorns), but it's over the heads, budgets, and WAF allowances of most people on the planet, let alone Klipsh Heads.

[ClaudeJ1]

His preference was for autoformers to gain match the drivers. I read somewhere where having L-pads had the greater distortion, introducing a higher peak to trough ratio and higher measured distortion.

He didn't believe in giving people the control over tweeters and squawkers for this reason. I don't recall seeing any sort of EQ or tone controls when I was at his house. He was feeding a Crown D-60 and a BGW 100 amp.coming out of a 2PH3 bos (RL in, RL out AND R+L for the C channel out). This is the exact setup I had for 30 years. All the stuff he wrote in the Dope From Hope, he actually built and used himself at his house, including false corners away from the real walls. He had a large living room. He had a Tandberg and, I think, a Revox. All his music was on reels. He only owned ONE LP. It had a plain white cover and was the original stereo broadcast of Leopold Stokowski for Bell Labs in 193. He didn't like any sort of commercial recording using multiple mikes. ALL of his recordings were done with only TWO spaced omni mikes, mostly of the Little Rock Symphony with various guest artists. He was very narrow minded in many ways.

[Hifi jim]

He was very narrow minded in many ways.

[:^)] Is that why he didn't believe cables could sound differently?

[ClaudeJ1]

He was very narrow minded in many ways.

Is that why he didn't believe cables could sound differently?

I think the Marketing people at Klipsch started insisted on wiring the Khorn Xovers with Monster Cable for a period of time to try and boost sales. I asked PWK what he thought of that idea (he was semi-retired in 1985 and not involved directly in production) and he said the largest voice coil was in the woofer and was 30 gauge wire, so he thought 10gauge monster cable was a waste of good copper.

[DrWho]

His preference was for autoformers to gain
match the drivers. I read somewhere where having L-pads had the greater
distortion, introducing a higher peak to trough ratio and higher
measured distortion.

I'm pretty sure the autoformer is
going to measure more distortion than an L-Pad, but the L-Pad does have
the frequency dependant behavior to it. However, I would argue that
both approaches could be implemented to acheive the same end result.

I
think PWK's comments in most cases needs to be taken in context of what
he's trying to communicate....which in the case of L-Pads is the fact
that most implementations probably ignored the frequency dependant
effects...so other speakers on the market change the frequency response
of each individual drive unit as the drive unit's amplitude was being
adjusted. At the same time, PWK was probably being a purest and voiced the
speaker for the most accurate tonal response he could achieve given all
the constraints....so adding an option for non-linear variability isn't
going to improve anything in light of his goal. At least that's the understanding I come
away with after reading his articles on the subject.

Many of PWK's quoted comments also come from a long time ago. I
haven't seen much published since the 80's, but the audio industry
didn't stop advancing after the 70's...

[Romak]

Hey... ill fitted briefs can change frequencies.[pi]

Sorry ladies[]

[ClaudeJ1]

Many of PWK's quoted comments also come from a long time ago. I
haven't seen much published since the 80's, but the audio industry
didn't stop advancing after the 70's...

Well Grasshopper. I agree with your last statement. Just know that I remember distinctly what he said and I didn't read it anywhere I spent a whle day with him from 9 to 7 i learned a lot in 10 hours. As to L pads vs. Autoformers, he had an article that showed more distortion from the L pad thatn the Autoformer with the available amplifiers of the day. I know Roy prefers resistors because the the phase issues of autoformers.

[garyrc]

• I talked with Roy Delgado on the phone in about 1988 .... in the course of the conversation he said, "Mr, K doesn't like equalizers."
• My guess is that he thought people would mis-adjust them the way audio stores comonly misadjusted tone controls
• That being said, I like both tone controls and equalizers, if properly designed and used.

[ka7niq]

I have owned a lot of Klipsch speakers, some needed tone corrections, some did not. Mark Levinsoon liked equalized Klipschorns, but he has this Audio Pallette Equalizer, and knows how to use it. My room will not support Klipschorns, so unless i move, I will never be able to try it.

[oldtimer]

Zombie thread.

[pauln]

Am I the only one that bothered to look over PWK's EQ patent? Take this quiz:

-------

Which functions was the EQ proposed to apply to the frequency spectrum?

A) Equalization

Compensation

C) Predistortion

D) All of the above

------

Maybe it's one of those peculiar engineering terms, but I find it funny knowing something of PKW's feelings about distortion that in the patent text one of the EQ's operations is repeatedly referred to as "predistortion". Maybe someone can explain about this predistortion function and its restoration (correction?) using the complementary circuit to the EQ circuit?

[Chris A]

• I talked with Roy Delgado on the phone in about 1988 .... in the course of the conversation he said, "Mr. K doesn't like equalizers."
• My guess is that he thought people would mis-adjust them the way audio stores commonly mis-adjusted tone controls
• That being said, I like both tone controls and equalizers, if properly designed and used.

If you look at commercial audio, the verdict is in: EQ is integral to doing business. In fact, I believe that the commercial horns that Roy has worked on basically assume that you are using EQ.

If you look at why PWK might not have advocated EQ, i.e., the technology of the day, then I believe his view on the subject would likely be in favor of EQ today if he were still alive (...this is a guess). EQ back in the 50s, 60s, and 70s wasn't very appealing to me either but with digital EQ today (and active biamping and triamping), my opinion on this subject has definitely changed.

Is it good if you don't have to use a lot of EQ? Well typically, yes, but maybe not always. I think that the advent of good EQ electronics allows for a wider latitude in design in order to achieve the holy grail of horn design: constant coverage (CC)--at least in the commercial realm. This means to me that good CC horns will require hf EQ-boost due to hf losses, etc., all other things being equal.

Low freq boosting is the norm in all direct-radiating subs, and in most horn-loaded subs (except perhaps the SPUD design).

Chris

[Don Richard]

Maybe it's one of those peculiar engineering terms, but I find it funny knowing something of PKW's feelings about distortion that in the patent text one of the EQ's operations is repeatedly referred to as "predistortion". Maybe someone can explain about this predistortion function and its restoration (correction?) using the complementary circuit to the EQ circuit?

Some frequency variations in the output of a loudspeaker are caused by factors that result in a distorted phase response. In correcting the frequency response of such a loudspeaker by using an EQ the phase response is also corrected. These "minimum phase" events may be EQed for frequency response sucessfully, but an irregular frequency response caused by acoustic cancellations cannot.

[Chris A]

Maybe it's one of those peculiar engineering terms, but I find it funny knowing something of PKW's feelings about distortion that in the patent text one of the EQ's operations is repeatedly referred to as "pre-distortion". Maybe someone can explain about this predistortion function and its restoration (correction?) using the complementary circuit to the EQ circuit?

Some frequency variations in the output of a loudspeaker are caused by factors that result in a distorted phase response. In correcting the frequency response of such a loudspeaker by using an EQ the phase response is also corrected. These "minimum phase" events may be EQed for frequency response successfully, but an irregular frequency response caused by acoustic cancellations cannot.

Note that in the early 1980s, I worked on "pre-distortion" techniques for land-based Vibroseis seismic exploration equipment. It worked but was sensitive to loading into the radiated medium (i.e., the earth coupling, which can vary by orders of magnitude), but it worked if it could be "tuned up".

On the notion of "phase distortion": I just wanted to add that "phase" is really only important in the crossover region between drivers with dissimilar phase/freq characteristics. It has been shown repeatedly that absolute phase distortion is not audible to the human ear of and by itself (at least, that's what the physiologists report). This is one reason why 2-way speaker systems can sound better than 3-way or more speakers--you are eliminating one or more crossover region that the human ear can hear. I think that what is important is "controlled phase distortion", ref. Floyd Toole's book.

If you are thinking about higher-order modes created by drivers/speakers that aren't in the source material, then that discussion should be in another thread, IMHO.

Chris

P.S.: If the discussion turns to impulse response of the speaker, then phase (or delay in this case) can matter, but note the very large delay errors that currently exist in Khorns, La Scalas, Belles, and virtually any other horn-loaded-bass speaker. If you can't hear the effects of that 8.4 ms delay (which is huge, by the way) between the Khorn tweeter and its bass bin, then I'd imagine that "phase accuracy" is not big on your list of audiophile issues.

However, I find that Jubilee bass-bin delay correction IS a big deal, so I'd imagine that anyone here that is sensitive to phase distortion is already actively tri-amping their Khorns, which can simultaneously correct for the delays between tweeter, midrange and bass bin. My guess is that the issues associated with the khorn bass performance will be mostly mitigated through active triamping/driver-horn delay correction.

Cheers...

[Don Richard]

On the notion of "phase distortion": I just wanted to add that "phase" is really only important in the crossover region between drivers with dissimilar phase/freq characteristics. It has been shown repeatedly that absolute phase distortion is not audible to the human ear of and by itself (at least, that's what the physiologists report).

Phase and frequency response are linked. In a minimum phase event, the reason there is a frequency response variation is because there is a difference in phase that causes it. In that case the phase differences may be inaudible but their effects, frequency response differences, are. But that's not all...

P.S.: If the discussion turns to impulse response of the speaker, then phase (or delay in this case) can matter, but note the very large delay errors that currently exist in Khorns, La Scalas, Belles, and virtually any other horn-loaded-bass speaker. If you can't hear the effects of that 8.4 ms delay (which is huge, by the way) between the Khorn tweeter and its bass bin, then I'd imagine that "phase accuracy" is not big on your list of audiophile issues.

In this case, phase differences between drivers within a loudspeaker cause comb filtering and increased side lobing. The lobing occurs in the region of frequency overlap between the two drivers. The comb filters extend upward through the frequency range. EQ cannot correct this but synchronizing the acoustic arrival times between the drivers with a delay will.

My guess is that the issues associated with the khorn bass performance will be mostly mitigated through active triamping/driver-horn delay correction.

And, similarly, time aligning any loudspeaker with such problems (most of them) will mitigate those problems.

So, in summary, although phase may not be directly audible, the effects of phase certainly are and are worth correcting.

[Chris A]

Don,

Actually, I believe that I was referring to the difference between a "BAM" and a "thwa-wump"...if you catch my drift. Comb filtering (actually two- and three-source steady-state interference fields in front of your speakers)...well...not so much.

While human hearing may tolerate time-invariant comb-filtering effects (see Toole's book, again), the ear apparently doesn't filter out impulse response anomalies: this is something that is very audible (having a great effect on the clarity of cymbals, for instance)--even considering precedence effects.

It seems as though many seem to not pay attention to this--an effect that is accentuated by the use of horn-loaded drivers. Time-aligning speaker drivers is a big deal (at least for me), and the ability to correct for this is a definite spin-off benefit of active digital crossovers with built-in EQ...the point related to the original subject.

Chris

[ka7niq]

On the notion of "phase distortion": I just wanted to add that "phase" is really only important in the crossover region between drivers with dissimilar phase/freq characteristics. It has been shown repeatedly that absolute phase distortion is not audible to the human ear of and by itself (at least, that's what the physiologists report).

Phase and frequency response are linked. In a minimum phase event, the reason there is a frequency response variation is because there is a difference in phase that causes it. In that case the phase differences may be inaudible but their effects, frequency response differences, are. But that's not all...

P.S.: If the discussion turns to impulse response of the speaker, then phase (or delay in this case) can matter, but note the very large delay errors that currently exist in Khorns, La Scalas, Belles, and virtually any other horn-loaded-bass speaker. If you can't hear the effects of that 8.4 ms delay (which is huge, by the way) between the Khorn tweeter and its bass bin, then I'd imagine that "phase accuracy" is not big on your list of audiophile issues.

In this case, phase differences between drivers within a loudspeaker cause comb filtering and increased side lobing. The lobing occurs in the region of frequency overlap between the two drivers. The comb filters extend upward through the frequency range. EQ cannot correct this but synchronizing the acoustic arrival times between the drivers with a delay will.

My guess is that the issues associated with the khorn bass performance will be mostly mitigated through active triamping/driver-horn delay correction.

And, similarly, time aligning any loudspeaker with such problems (most of them) will mitigate those problems.

So, in summary, although phase may not be directly audible, the effects of phase certainly are and are worth correcting.

All one has to do is sit in front of a pair of Tannoy Dual Concentric's to get a demonstration of the audibility of phase and time alignment.