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Sub for Jubilee - Klipschorn


RSVRMAN

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The argument of direct radiator producing all this distortion, is just simply BS on a Sunday morning.  Yes, the cone does have to move more but, when we start talking about direct radiator subs the same size as some of the horn subs, the argument get's very fuzzy.  Also, when we are talking about sub distortion, there are guidelines on what is considered audible.  Databass.com has established 10% in the LF.  I can tell you that drivers like Dayton UM 18 will produce 2-5% in the LF which is excellent.  It is kinda like talking about amp specs and amp X has a THD of 0.004 compared to amp Z with a THD of 0.90.  These two amps will sound the same.  For those that say they can hear 1 or 2 % distortion, hearing is like a bell shaped curved following a normal gaussian distribution.  If you can hear 1% distortion, 99.9% of the population can't 

 

Horn subs operate well in a very limited passband, most need to be XO lower than a direct radiator. They are larger than most people are willing to live with, lack LF extension unless the box is huge.  Horn subs are not the perfect solution for bass in every situation.  The mind set is one track on this forum at times and very misleading to newcomers.  Even in pro application, direct radiator are favored in smaller venues.  Now, the HT theater or music room is even smaller.

 

When talking about all this so called distortion, this only comes into play at extreme levels.  For my room, I can hit 135-140 db with direct radiator subs but, I never listen at those level for more than a few second.  So, since most people are not listening at extreme levels, it is a mute point.  It is like talking about a car that can hit 220 mph.  It is not practical, safe, or something to encourage others to do.  I keep ear protection device in my room because I would like to keep my hearing.

 

All the different design of subwoofers have their pro's and con's.  If they did not, there would only be one type of subwoofer being built.

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People are now using large subwoofers than the old 10-12 in drivers.  There are now larger and better drivers used in direct radiator subwoofer in the home and most of the sited material concerning direct radiator and horn sub is old and out of date.  Even the construction of subwoofers has changed over the years.  It is just like many other fields, the questions remain the same, the answer have changed.  A great system for music or HT can be put together with all the various designs of subwoofers.

 

 

 

 

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In the case of subwoofers, isn't modulation distortion even less of an issue? When Paul wrote his papers, he was talking about 60hz and 250 or something close to that. Most subwoofers only play to 80hz and in many cases even less than that. 

 

What is the modulation distortion in a speaker that only plays ~40hz of the audible spectrum? (20-60hz)

 

As @derrickdj1 stated, the distortions people are mentioning are only at very loud levels. At normal listening levels, well-built modern direct radiator subs should be virtually distortion free. Horn-loading will always be better, but in a normal listening room, large direct radiating subs can do the job. I think it is important not to outright dismiss a certain sub just because of bias. There are good and bad speakers of every category. Perhaps it is also important to note that Klipsch only makes a couple horn-loaded subs in the pro line that are absolutely huge. Even there, direct radiators are more prevalent. 

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20 minutes ago, Grizzog said:

In the case of subwoofers, isn't modulation distortion even less of an issue? When Paul wrote his papers, he was talking about 60hz and 250 or something close to that. Most subwoofers only play to 80hz and in many cases even less than that. 

 

What is the modulation distortion in a speaker that only plays ~40hz of the audible spectrum? (20-60hz)

 

As @derrickdj1 stated, the distortions people are mentioning are only at very loud levels. At normal listening levels, well-built modern direct radiator subs should be virtually distortion free. Horn-loading will always be better, but in a normal listening room, large direct radiating subs can do the job. 

Horn loading will in most cases be louder, not necessarily better.  THX recommendations are currently to be able to hit 128 db. in the HT for a system with 9-13 speakers with redirected bass between 31.5-63 Hz.  Anything more and you are clipping in the digital domain based on how movies are produced.  It is just like saying a 3 or 5 way design is inherently a better design speaker.  All the various XO's bring there own problems.  Now if you prefer one over the other, that is a personal choice that nobody can argue with.:)

 

Which subwoofer is better depends on what type of speakers you have and can only be made in that context.  Synergy of a system is a major factor in the end result of the SQ.  What sounds good is very subjective and and it only comes down to what you like, not someone else.

 

There seems to be a consensus among the subwoofer experts that having more than one sub is better.  Also, 4 subs will give the best room response but, there is no consensus that one design is  the perfect one and meant for most of the population.  At least, I've not coming across it in my readings over the last several years.

 

 

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1 hour ago, derrickdj1 said:

The argument of direct radiator producing all this distortion, is just simply BS on a Sunday morning.  Yes, the cone does have to move more but, when we start talking about direct radiator subs the same size as some of the horn subs, the argument get's very fuzzy.  Also, when we are talking about sub distortion, there are guidelines on what is considered audible.  Databass.com has established 10% in the LF.  I can tell you that drivers like Dayton UM 18 will produce 2-5% in the LF which is excellent.  It is kinda like talking about amp specs and amp X has a THD of 0.004 compared to amp Z with a THD of 0.90.  These two amps will sound the same.  For those that say they can hear 1 or 2 % distortion, hearing is like a bell shaped curved following a normal gaussian distribution.  If you can hear 1% distortion, 99.9% of the population can't 

 

Horn subs operate well in a very limited passband, most need to be XO lower than a direct radiator. They are larger than most people are willing to live with, lack LF extension unless the box is huge.  Horn subs are not the perfect solution for bass in every situation.  The mind set is one track on this forum at times and very misleading to newcomers.  Even in pro application, direct radiator are favored in smaller venues.  Now, the HT theater or music room is even smaller.

 

When talking about all this so called distortion, this only comes into play at extreme levels.  For my room, I can hit 135-140 db with direct radiator subs but, I never listen at those level for more than a few second.  So, since most people are not listening at extreme levels, it is a mute point.  It is like talking about a car that can hit 220 mph.  It is not practical, safe, or something to encourage others to do.  I keep ear protection device in my room because I would like to keep my hearing.

 

All the different design of subwoofers have their pro's and con's.  If they did not, there would only be one type of subwoofer being built.

 

Only those with uneducated ears could not detect distortion, put these different designs in the same room next to each other at the same volume just about anybody would be able to detect big differences in sound.

 

Mentioning distortion percentage without adding SPL numbers tells us nothing.

 

Pro sound venues use direct radiators because they are many times cheaper than good horns.

 

Bass is where you really need horn loading to keep distortion in check, most models only horn load upper frequencies because of cost and size, nothing else.

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8 minutes ago, jason str said:

 

Only those with uneducated ears could not detect distortion, put these different designs in the same room next to each other at the same volume just about anybody would be able to detect big differences in sound.

 

Mentioning distortion percentage without adding SPL numbers tells us nothing.

 

Pro sound venues use direct radiators because they are many times cheaper than good horns.

 

Bass is where you really need horn loading to keep distortion in check, most models only horn load upper frequencies because of cost and size, nothing else.

You have said something important, spl.  For home use not at extreme levels, the distortion you are referring to is not an issue.  This is even more true comparing similar size subs of the various designs.  One cannot talk about distortion without talking about recognized established level where most people can detect it and those levels are not 1 or 2% in the deep bass range.  Produce credible  evidence backed by solid science.  The laws of physic and science are not easily changed by personal opinion.

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2 minutes ago, derrickdj1 said:

You have said something important, spl.  For home use not at extreme levels, the distortion you are referring to is not an issue.  This is even more true comparing similar size subs of the various designs.  One cannot talk about distortion without talking about recognized established level where most people can detect it and those levels are not 1 or 2% in the deep bass range.  Produce credible  evidence backed by solid science.  The laws of physic are not easily changed by ones opinion.

 

If distortion was not an issue Klipsch would never have sold one single Klipschorn, Jubilee or any other horn loaded bass cabinet design ever.

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No one has said distortion is not an issue.  The question is what level is acceptable.  Just like the Khorn and Jub, they are not meant for every room or personal taste.  It is absurd to think that one solution fits all cases.  Other factors have to be taken into consideration when putting together a music or home theater system.  Most of us here understand the benefits of a horn design but, we all have different systems based off our needs and personal goals.

 

I could buy Khorns, Jubs or some of the other Klipsch offering today but, they don't fit my need or desire.  It's not good or bad.  Once again, in comparing subs, put similar size boxes together and the area becomes real fuzzy.  Even Klipsch has more than one offering because there is no one great and perfect solution for every case. 

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1 hour ago, Grizzog said:

...the distortions people are mentioning are only at very loud levels. At normal listening levels, well-built modern direct radiator subs should be virtually distortion free.

I think you missed something in your thinking about bass performance: it's loud all the time.  See:

and...

and...

 

1 hour ago, Grizzog said:

In the case of subwoofers, isn't modulation distortion even less of an issue? When Paul wrote his papers, he was talking about 60hz and 250 or something close to that. Most subwoofers only play to 80hz and in many cases even less than that. 

 

What is the modulation distortion in a speaker that only plays ~40hz of the audible spectrum? (20-60hz)

 

I believe that you should be asking the opposite question: how little bandwidth does modulation distortion to be audible...and I believe that you're thinking about FM distortion of subwoofers, not AM distortion--which is the predominant distortion source at low frequencies.  Refer to Klippel's papers for the information on relative levels of modulation distortion.

 

When you actually see the modulation sidebands using dual tones using direct radiating woofers, even at 20 and 35 Hz, I think you'd agree that this is an issue for every person with a hi-fi setup.  When you actually hear that infrasonic bass reproduced without those high levels of modulation distortion, it becomes very clear (at least to me) which type is preferred. 

 

Chris

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One other subject that I think a lot of people shy away from is transient performance of bass bins and subwoofers.  I'm pretty sure that most people can hear the difference in performance using good horn-loaded bass bins and subwoofer(s) versus using good direct radiating bass bins/subwoofer(s) in everything but the smallest of listening rooms.  What's usually not talked about is "why do they sound different?" 

 

For me, the answer is clearly seen in the group delay curves.  As the frequency goes lower and lower, the differences in group delay curves for horn-loaded vs. direct radiating (vented) are usually quite clear.  I've not pressed this discussion on this forum since the audibility of LF group delay hasn't been measured, but I'm willing to say at this point that it's a clear "smoking gun" that can be pointed to. 

 

What's unclear to me is the fervor by which some deny the audible differences in horn-loaded subs vs. direct radiating ones.  That's something that can be attributed to something else, I believe...;)

 

Chris

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Here is a quote from Bill Fitzmaurice on group delay: For all practical purposes it can be ignored. Group delay's audibility is closely related to the same physiology of human hearing responsible for directional location, and in the nether regions neither is within our ability to easily discern, if at all.

  how relevant the source quoted is with regard to real world situations, as opposed posing worst case theoretical discussion. In most listening rooms you can't even hear the difference in arrival time between the mains and subs that are placed even 15 to 20 feet apart, so you're surely not going to hear group delay. Where the group delay gets long enough to conceivably be problematic the period of the wave is so long that your ear/brain ignores the fundamental and derives its cues from the harmonics, in timing, phase, location, even pitch.

 

Even with that being said, most modern avr's correct for group delay.  Group delay is a function of the FR and change of frequencies with phase changes.

There are changes in different box designs such as sealed, vented and band pass.  In layman's term, this is related to tightness of the bass. Now the discussion can shift toward knowing the differences between system and relating that to what is audible.  For example a 20 Hz sound with a 75 ms delay is not very audible.  The sound wave is near 80 + ft. long.  Most of us don't have our subs that far away.  My furthest is around 28 ft. from the MLP.

 

Bass tightness is also a function of how well the sub produces lower frequencies.  Sealed subs have a reputation of being tighter.  This is partly due to there nature roll off below 35-40 Hz.  What is actually happening  is that the sealed sub is not faithfully producing the lower frequencies below the roll off.  In essence, this is distortion by definition.

 

You couple this with all the reflections in the small room, the picture of group delay significance becomes more fuzzy as a major point.  It should be also pointed out the the most significant part of group delay occurs near tuning.  Boxes can and are designed that make this a mute point, such as LLT subs.  By the time group delay would become a factor, there will be few if any music notes being generated at those low frequencies.  The old pipe organ argument does not hold water at the frequencies either.

 

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Yes, yes. I know what  Bill F. is saying about group delay. 

 

The fact remains that the audibility of group delay below 500 Hz hasn't been measured (to my knowledge).  Therefore, to say that group delay isn't audible at low frequencies is more a statement of belief than fact. 

 

In any case, GD is definitely correlated to the "bass flabbiness" sound.  Correlation doesn't imply causation, but I look to GD as a strong indicator. When GD below 100 Hz goes above 10-20 ms, bass flabbiness is typically present, and usually due to more aggressive bass reflex port designs than what you hear with something like a Cornwall, which has much less GD growth than many other loudspeakers.

 

Chris

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On 2/4/2017 at 3:20 AM, RSVRMAN said:

My goal is for the subwoofer to be able to clearly hit the 16-17hz range. Lower even better.  

I hear this all the time, and I firmly believe it to be an unrealistic goal. Not unobtainable, just not practical in the majority of cases. :emotion-55:

 

No, I'm not a bass Luddite. I appreciate healthy performance below 60Hz as much as the next person. This isn't a special case, and you're talking about capability way out on the tail end of the bell curve.

 

Having spent considerable time around real world stuff that makes SPL in that freq range (the infra-bass region) I'll tell you that:

A. It's typically not musical

B. Not subtle in any way

C. The required acoustic power to approach anything resembling realistic playback levels is beyond the capability of traditional dynamic driver design.

D. The noise floor down there is ridiculous.

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If you're wanting something controversial to talk about, here it is:

 

I have evidence that points to group delay--and not so much modulation distortion--as the source of the differences in sound of bass bins and subwoofers between direct radiators and horn loaded. 

 

I can say this after extensive listening trials between loudspeakers with differing levels of dual-tone sidebands but similar levels of group delay.  When group delay rises, it becomes audible. 

 

One thing that I believe people have forgotten is that while interaural time delay could be the mechanism that the human hearing system uses down to 500 Hz, clearly there are other mechanisms that are coming into play at lower frequencies. 

 

As an example of this phenomenon of differing hearing mechanisms coming into play, I'll refer to the data on sound localization.  vertically vs. horizontally.  For years, it was said that humans cannot judge vertical locations of sound with nearly the precision as horizontally.  Then someone did some tests with real subjects, and found that humans do localize just about as well vertically as horizontally.  I believe one of the reasons why someone did the tests is due to the measured hearing system performance of barn owls (who have asymmetries in their face structure not only horizontally, but also top to bottom, left to right. (Owls must be able to hear the direction of their prey very accurately in order to eat for a living.)   It turns out that the vertical differences in human external ear shape (the penna) leads to differences in FR of hearing versus elevation angles, just as much as interaural delay helps horizontally. 

 

It's that type of assumption, that we "know" what the hearing mechanisms are and can predict hearing performance without measuring it, that is the issue.  In the mean time, the observations that correlation between GD levels and flabby bass performance will have to suffice for me until someone actually does the GD audibility tests. 

 

This is the sort of thing that I've found about hi-fi.  People assume that human hearing is completely linear and that they know everything there is to know about how and why it works.  It turns out that this is the source of most of the problems in hi-fi - people "knowing"--without measuring or testing.  The human hearing system is profoundly nonlinear and extremely surprising in terms of its embedded processing performance that is coupled to the ears/eardrums, etc. via the coupled human brain.

 

This is also the case with audibility of modulation distortion.  Earl Geddes did all of his audibility of modulation distortion tests using college students, but everything was at 80 dBA and below--using headphones, and that negates the penna and HRTF performance of the human hearing system, which he didn't control for in his tests.  It turns out that modulation distortion does become audible above 80 dBA.  The level of modulation distortion in loudspeakers is a strongly nonlinear function of on-axis SPL.  In other words, his tests didn't prove what he intended to prove.

 

Chris

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The whole point  of this discussion is that all the different subwoofer designs have pro's and con's.  I have heard horn, vented, sealed,and bandpass subwoofers.  I like them all.  The intended application  and the system that it is used in makes all the difference in which design will meet your needs.  

 

Quiet_Hollow is correct:

A. It's typically not musical

B. Not subtle in any way

C. The required acoustic power to approach anything resembling realistic playback levels is beyond the capability of traditional dynamic driver design.

D. The noise floor down there is ridiculous.

 

If the OP wants to achieve meaningful output in this range, consider having  multiple subwoofers and having a subwoofers of large size.  This applies to all the usual subwoofer designs.  For most music, there is little need for a sub to go lower than 35 Hz.  Sound engineers routinely cut frequencies lower than 35-40 Hz.  Rumble filters are used in music venues to cut the very low frequencies because it can be detrimental to the SQ.

 

 

 

 

 

 

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7 hours ago, Quiet_Hollow said:

I hear this all the time, and I firmly believe it to be an unrealistic goal. Not unobtainable, just not practical in the majority of cases. :emotion-55:

 

No, I'm not a bass Luddite. I appreciate healthy performance below 60Hz as much as the next person. This isn't a special case, and you're talking about capability way out on the tail end of the bell curve.

 

Having spent considerable time around real world stuff that makes SPL in that freq range (the infra-bass region) I'll tell you that:

A. It's typically not musical

B. Not subtle in any way

C. The required acoustic power to approach anything resembling realistic playback levels is beyond the capability of traditional dynamic driver design.

D. The noise floor down there is ridiculous.

Many goals are unrealistic, thats the idea of making it a goal and not a requirement :)

 

I'm looking at the extension beyond what the Jubilees are capable of. I'm fully aware that most music cuts off above 30ish hz. I listed before that I do listen to music that dives deeper than that. I'm also 60% music 40% movies. Almost every action movie could benefit from having the lower spectrum I'm looking. 

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5 hours ago, derrickdj1 said:

 

If the OP wants to achieve meaningful output in this range, consider having  multiple subwoofers and having a subwoofers of large size.  This applies to all the usual subwoofer designs.  For most music, there is little need for a sub to go lower than 35 Hz.  Sound engineers routinely cut frequencies lower than 35-40 Hz.  Rumble filters are used in music venues to cut the very low frequencies because it can be detrimental to the SQ.

 

At his point, it will only be one subwoofer. This is a requirement, as I just do not have room for another. Thankfully I'm somewhat flexible on size. I can say with the current music list I have, my previous SVS Ultra 13 did quite a bit of work in the 20hz spectrum. 

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