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Peak Power Handling of Khorn Bass Bin ? ......................

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Guest wdecho

John there are always going to be disagreements between engineers on any subject especially if the final result is audio being so subjective. Ears are the final tool to use not graphs or plots. You cannot deny that PWK's bass unit in the K-horn has been successful for over 70 years and is till being made and sold to discriminating listeners because of what their ears tell them and not graphs and plots and many papers disagreeing with what PWK found sound best to him. Even in the 70's K-horns were not often reviewed in a excellent way by the reviewers in the rags at the time. What they do best is simulate a live performance in ones living room as no speaker( other than other big horns) that I have heard in my lifetime.There may be other speakers that are still being sold after being introduced 70 years ago but right now I cannot think of another brand. I do think "troll" was a little harsh but negative comments on horn loaded bass speakers on a Klipsch forum would be best said on another forum. I respect your opinion, many will agree with you, but very few on this forum. If you want to participate on this forum and make friends just let it go with what has already been said. There will ultimately be no winners just harsh feelings. 

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4 hours ago, John Warren said:

 

Significantly?  Hardly...Radiation resistance is the resistive part of the change.  Between 90 and 200Hz the impedance is about 5 Ohms, i.e. like a resistor.  That's the radiation resistance and where the response peak is measured and the sensitivity a maximum.  The magnitude of the radiation resistance is around an Ohm...

 

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On 8/23/2018 at 7:54 AM, Chris A said:

Additionally, the modulation distortion goes approximately as the inverse of the real part of the throat radiation impedance (but perhaps not linearly). 

The subject of this thread is "peak power handling of the Khorn bass bin", but no matter--you're obviously upset by something. 

 

The problem is that you also need to measure the modulation distortion (requiring dual tone measurements--especially if you're making extraordinary claims--which require extraordinary evidence).  

 

Here is one such measurement using K-43 woofers, first in a large vented box and then in an MWM horn:

 

Mod Distortion Sideband Levels Horn vs Port.JPG

 

These measurements are half space--on a concrete floor, i.e., boundary gain is limited to basically just the horn itself and the vented box in the presence of a room floor.  The horn disproportionately gains from having quarter space or eighth space loading over the vented box, which it is deprived of in this measurement.  It's also not an exhaustive measurement in that the full Klippel modulation distortion test was not run.

 

This says to me at least that you're trying to measure the bass modulation distortion by using an indirect means--which is not a very "fit for purpose" way to do it since it clearly seems to add confusion to the issue rather than clarify it.  If you're trying to say that direct radiating drivers (vented boxes) have as low or lower distortion than the same drivers used in a good horn, you've yet to show those data, at least to me. 

 

I'm not sure why you're spending time trying to prove PWK was wrong.  In almost every way that I've investigated, PWK was correct...by my own measurements.  If I were in your shoes, I would instead be trying to calibrate my ears to real life performance vs. vented vs. horn-loaded.  I was there during the demonstration that MikeTN mentioned above in Hope years ago.  I'll never forget what that listening demonstration showed me.  I still own my Jub bass bins, and probably will for some time to come.  I do plan to divest my collection of the vented bass bin loudspeakers that I do own since their bass distortion (i.e., modulation distortion) is significantly higher audibly than horn loaded.  But this really isn't the right thread to a full presentation on that subject...so I'll pass. 

 

BTW, this subject been arguing many times on this forum, and I think few people are going to change their views as William has indicated above--which is not to say that it isn't an interesting subject for others to investigate for themselves.  What I've found however is that not all ears are created equal--and many people have apparently accommodated to the sound of bass modulation distortion (even in the room in Hope where I heard that now-famous demonstration of vented vs. horn loaded).  I can tell you that, by far, most professionally trained musicians prefer the sound of the Khorns over direct/vented boxes.  I believe that the reason is that they have calibrated their hearing first to the real thing before listening to direct radiating vs. horn loading loudspeakers.  In my own experience, this trial has always come out the same way. 

 

If you grew up listening to direct radiating loudspeakers instead of the real thing, I find that you'll be much more likely to choose those sort of bass bin types that you listened to, instead of something that sounds a lot more like the real thing.

 

Regards,

 

Chris

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5 hours ago, John Warren said:

 

Why is it that good engineers, with good test gear just can't seem to replicate PWK's work?

 

https://asa.scitation.org/doi/10.1121/1.3437441

 

Abstract
It has been stated that the total modulation distortion produced by a loudspeaker system is inversely related to the efficiency of the system, and that horn‐loaded systems display less of this distortion than the best direct radiators [P. W. Klipsch, “Modulation Distortion in Loudspeakers,” J. Audio Eng. Soc. 17, No. 2 (Apr. 1969)]. This statement runs contrary to modulation theory, which relates modulation distortion to the amplitude or velocity of diaphragm vibration. Measurements were made both on a high‐quality, full‐range horn‐loaded system and on a large, full‐range direct‐radiator system. Each system was driven with the sum of a 41‐Hz and a 350‐Hz tone to evaluate woofer distortion, and with the sum of a 510‐Hz and a 4.4‐kHz tone to evaluate mid‐range distortion. Output levels ranging up to 110 dB SPL were used. The acoustic output of the speakers was fed to a real‐time spectrum analyzer, and total modulation distortion calculated after the method described by Klipsch. Under all conditions measured, the direct radiator produced substantially less distortion. For example, at 110 dB SPL output, its woofer modulation distortion was 3.9% vs 5.8% for the horn system.

 

 

 

 

 

I can't really comment on this John since I don't have access to this paper and have no idea of all the variables at play.

 

This paper by John Allen, with test performed by Roy Delgado, Jim Hunter and Kerry Geist controls some important variables like the same driver design was used in both systems.

 

woofer_distortion.pdf

 

 

miketn

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Guest wdecho
3 hours ago, Chris A said:

 

  What I've found however is that not all ears are created equal--and many people have apparently accommodated to the sound of bass modulation distortion (even in the room in Hope where I heard that now-famous demonstration of vented vs. horn loaded).  

 

If you grew up listening to direct radiating loudspeakers instead of the real thing, I find that you'll be much more likely to choose those sort of bass bin types that you listened to, instead of something that sounds a lot more like the real thing.

 

Regards,

 

Chris

I couldn't agree more. Some are perfectly happy with Wal-mart gear saying they cannot tell a difference when listening to a high end system. A good friend of mine always says he cannot tell a difference in an upper end restaurant vs an all you can eat buffet. Much the same with audio gear and music. Those people can save a lot of money whether food or music. 

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1 hour ago, mikebse2a3 said:

I can't really comment on this John since I don't have access to this paper and have no idea of all the variables at play.

 

Mike--that author apparently has an axe to grind (...in the year 1974 when the article was published, that is...).  A fair example would be to use the same woofer in vented-direct radiating mode, and then with a well-designed horn in front of it--like the article that you linked to (and I cited its data), above.  That's apparently not what this author did. Usually, Army publications are reasonably done, but sometimes you see outliers--apparently like that one. What was done in that "study" was apparently particularly badly conceived in order to get the answer they wanted.

 

I might point out that PWK tried as he might to make direct radiating woofers (ported or sealed) to sound good enough to use between a stereo pair of Klipschorns in order to form his now-famous three-loudspeaker array, but failed at least twice: the first time was the Heresy (which was originally billed as a center loudspeaker), and later the much larger Cornwall (again billed as a center loudspeaker).  He later changed his mind after time had passed after he discovered that it was modulation distortion that was the limiting factor--later writing the article referenced above (Modulation Distortion - parts 1, 2, and 3).

 

Chris

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On 8/19/2018 at 2:50 PM, Schu said:

What part of that observation Roy?

I am curious.

"Recapping, there's nothing intrinsically "low distortion" associated with a woofer cone working hard into the radiation resistance of the Klipschorn throat.  The net effect is higher sensitivity over that narrow range at the expense of a whole lot of other parameters equally important to good sound."

 

this statement.  working hard into a radiation resistance.....maybe it would be better if it was working hard into imaginary part of radiation resistance.  :)  i think it works the other way....because of the radiation resistance, the woofer doesnt have to move much and thus doesnt have to work hard.  and it seems that we are totally ignoring the impedance matching that a good, well designed horn offers.  

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49 minutes ago, Chief bonehead said:

this statement.  working hard into a radiation resistance.....maybe it would be better if it was working hard into imaginary part of radiation resistance.  :)  i think it works the other way....because of the radiation resistance, the woofer doesnt have to move much and thus doesnt have to work hard.  and it seems that we are totally ignoring the impedance matching that a good, well designed horn offers.  

 

But the imaginary part of the impedance isn't that large when the radiation resistance is significant.  By way of the impedance matching, a larger fraction of the power sent to the driver is dissipated through the radiation resistance whilst less is stored into the reactance.

 

Just because the cone moves less at peak sensitivity doesn't mean it's not working hard.  The mechanical stresses are higher and that leads to it's own non-linearities.  

 

   

 

 

 

 

 

 

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1 hour ago, John Warren said:

 

But the imaginary part of the impedance isn't that large when the radiation resistance is significant.  By way of the impedance matching, a larger fraction of the power sent to the driver is dissipated through the radiation resistance whilst less is stored into the reactance.

 

Just because the cone moves less at peak sensitivity doesn't mean it's not working hard.  The mechanical stresses are higher and that leads to it's own non-linearities.  

 

   

 

 

 

 

 

 

you kinda of made my point.  you want to have as resistive a load over as large a bandwidth as possible.  but it just seems that you suggest we should just have a woofer flopping in the wind with no loading because that makes the woofer not work so hard.  the horn presents an impedance matching device in order to help the woofer work more efficiently; not work harder.  the mechanical stresses are very evident when the woofer moves more. but we will have to agree to disagree.  :)

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Not sure about making points, it's what I've been saying all along.

 

This is my statement you took exception to:

 

"Recapping, there's nothing intrinsically low distortion" associated with a woofer cone working hard into the radiation resistance of the Klipschorn throat.  The net effect is higher sensitivity over that narrow range at the expense of a whole lot of other parameters equally important to good sound."

 

I don't see where I say anything about a woofer "flopping in the wind" with no load?  (btw, "working hard" was a figure of speech)

 

I state clearly that the cone works into the radiation resistance, nothing else.  

 

2 hours ago, Chief bonehead said:

you want to have as resistive a load over as large a bandwidth as possible. 

 

And that's what I meant by " at the expense of a whole lot of other parameters equally important to good sound."

 

Bandwidth is the price paid for that sensitivity.  The bandwidth of the Klipschorn radiation resistance is what? perhaps 2 octaves?  

 

To extend the bandwidth you resorted to the Jubilee which is more complex, two drivers, more wood, more cost.

 

 

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9 hours ago, Chris A said:

 ... I can tell you that, by far, most professionally trained musicians prefer the sound of the Khorns over direct/vented boxes.  I believe that the reason is that they have calibrated their hearing first to the real thing before listening to direct radiating vs. horn loading loudspeakers.  In my own experience, this trial has always come out the same way. ...

 

J. Gordon Holt said just about the same thing -- mentioning Klipschorns by name -- based on the mail of Stereophile readers who were musicians. 

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2 hours ago, garyrc said:

 

J. Gordon Holt said just about the same thing -- mentioning Klipschorns by name -- based on the mail of Stereophile readers who were musicians. 

 

Yet virtually all control rooms use the same large format configuration for their monitors, dual 12 or 15" direct radiators or 10"x4 quads.   

 

Go figure?

 

tsm-300_studio.jpg

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GenelecStudioPicAbdala.jpg

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Isn't there an element in the mastering and "control" rooms where the enclosure is always housed flush with the front boundary layer... as in your photos?

This isn't really an option for the home environment where a purpose built room/chamber isn't always possible.

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4 hours ago, Schu said:

Isn't there an element in the mastering and "control" rooms where the enclosure is always housed flush with the front boundary layer... as in your photos?

This isn't really an option for the home environment where a purpose built room/chamber isn't always possible.

 

I know this was directed to John Warren, but in the many control rooms I've been in, I'd say almost all have the speakers flush mounted.  I've been in a few that didn't use flush mounting.  But it is true that flush mounting will often:

  • Increase bass by a few dB
  • Lower bass distortion a bit

Also, there a few studios, including that of Leo De Gar Kulka, and, for a while, the Sausalito Record Plant, that had horn loaded monitors.  One studio, down South somewhere, had K-horns (I forgot the name).  Places like Sound Genesis sold La Scalas to be used as flush mounted monitors.

 

I like Chris A's point, in another thread, that there is an element of cliquishness among those who make such decisions at studios.  Could that mean that if "everybody" uses dual 15" direct radiating woofers, that you can see pump (too far) in a sexy manner, that the use of that configuration might be slightly self perpetuating?

 

 

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Over the years I have owned the entire Klipsch Heritage Series of speakers except the Belle. Currently own H III’s. Have also owned numerous “conventional” direct radiating speakers. I am not an engineer or scientist, and thus do not understand much of what is posted regarding horn/speaker design theory. My ears tell me that PWK and Roy’s science trumps the science of the naysayers. 

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Guest wdecho
21 minutes ago, Kevin S said:

Over the years I have owned the entire Klipsch Heritage Series of speakers except the Belle. Currently own H III’s. Have also owned numerous “conventional” direct radiating speakers. I am not an engineer or scientist, and thus do not understand much of what is posted regarding horn/speaker design theory. My ears tell me that PWK and Roy’s science trumps the science of the naysayers. 

I say always trust your ears vs paper, graphs, plots, engineers, etc. Much as the vinyl vs CD's debate. But will agree not everyone hears the same. If one cannot tell a difference they could be considered blessed. I forget the correct figure PWK once said but it was something like " Only 3% of the population hears what I can hear." I can hear a difference between a chop, chop CD vs a LP. But then I do not have a 5 grand DAC to compare a LP against a CD. 

 

I believe there are many times audio buffs spend tons of money for different component and claim it to be superior to less expensive gear only because of the money spent. Your brain tells you it must sound better, look at all the money I just spent for this thing. I have been guilty myself many times in the past. 

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14 minutes ago, wdecho said:

I say always trust your ears vs paper, graphs, plots, engineers, etc. Much as the vinyl vs CD's debate. But will agree not everyone hears the same. If one cannot tell a difference they could be considered blessed. I forget the correct figure PWK once said but it was something like " Only 3% of the population hears what I can hear." I can hear a difference between a chop, chop CD vs a LP. But then I do not have a 5 grand DAC to compare a LP against a CD. 

 

I believe there are many times audio buffs spend tons of money for different component and claim it to be superior to less expensive gear only because of the money spent. Your brain tells you it must sound better, look at all the money I just spent for this thing. I have been guilty myself many times in the past. 

I confess to not being a golden eared audiophile. I do not hear the differences people claim to hear in electronics, cables etc. But I consider myself very able to discern differences in the sound of speakers and the changes of their placement in the room. Those changes swamp any differences in electronics, cables etc. for me. So I learned years ago, but later than I probably should have, to focus my efforts on that. PWK’s (and Roy’s updated) Heritage speakers, when placed as they were designed by PWK to be placed, just sound “better” to me. As far as I am concerned, that, and the fact that they have survived the test of time in the marketplace, proves the science behind them to be valid. 

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On 8/26/2018 at 2:31 AM, garyrc said:

...that there is an element of cliquishness among those who make such decisions at studios.  Could that mean that if "everybody" uses dual 15" direct radiating woofers, that you can see pump (too far) in a sexy manner, that the use of that configuration might be slightly self perpetuating?

I've often wondered why people that make and use "studio monitors" (the real kind used in studios) call them by that name instead of just "loudspeakers".  I've come to the realization that they're actually just loudspeakers that emulate the type of loudspeakers that consumers use (i.e., they're not really good reproducers) but they represent a median of performance of a lot of loudspeakers all at once.  This is the reason why they typically have poor bass performance, but otherwise flat on-axis frequency response because flat FR represents the median frequency response of a lot of consumer loudspeakers (with rolled-off lows). 

 

Hence you have the Yamaha NS-10M used as a studio monitor.  These didn't sell well as consumer loudspeakers--because there is nothing special about them.  They're just plain and ordinary small loudspeakers, but they got the reputation of being a "population mean" loudspeaker--thus making it a "studio monitor":

 

bpidrlu2scatdkfrctss.jpg

1107185521_YamahaNS-10Mwaterfallscreenshot.JPG.8b8172bd796b7ac8851a80af83ddd676.JPG  980578180_YamahaNS-10Mstepscreenshot.JPG.0bccecf8b2ed157b84c6b13e20594736.JPG

 

 

The same thing is true of the the even more infamous Auratone 5C Sound Cube, used for pop/rock mixing and mastering since the early 1970s and are still used today in near-field listening:

AUT5CSINGLE-13367da04d392003b3fdd73d28cf

1787642924_Auratone5Cwaterfallscreenshot.JPG.d58975f984eeaba899be7307a801989f.JPG  1841234769_Autatone5CStepscreenshot.JPG.f5fcc46d7b4aa9abbd06db8ea64447c1.JPG

 

Note again their significant low frequency roll offs, but also their good decay and step response performance, making them supposedly better able to reveal issues during mixing and mastering.  (All plots are taken from Recording Studio Design, 2nd Ed. (2008 Focal Press), Newell, pg. 483.)

 

Neither of these "reference studio monitors" are what I'd call compelling in terms of their listening performance (i.e., I wouldn't want to spend my time listening to them in hi-fi enjoyment), but they're still used in some mixing and mastering duties. 

 

Back before the Auratone and the later NS-10M near-field monitors, there were a lot of JBL and later Westlake monitors used, but for reasons that I believe were more related to the engineers personal preferences (and no other reasons) over other loudspeaker types of that time.  Gradually, those big JBLs/Westlakes gave way to the smaller nearfield monitors that cost much less and took up much less room in cramped, mobile recording/mixing/mastering studios. 

 

The big Westlake TM-series monitors shown above have much better low frequency extension, but likely much worse step and decay performance due to their large/ heavy direct radiating 15" woofers (and vented to boot, which increases the decays and step responses measurable and audibly). 

 

IMG_52121.jpg

 

Chris

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Guest wdecho

I've heard much the same about studio monitors. Not especially desirable in a consumer living room. They are made for a specific purpose, making music not listening to music in ones home. But to each his own. I still remember when Altec horns dominated the studio because with horns someone off key was immediately pointed out.  

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