A few percent of harmonic distortion may not be very audible, especially at bass frequencies, but from my experience, doppler and I.M. are definitely audible.
I would agree with you here, I think that the recordings are the limitation these days. It is very hard to find good ones. That said it is not at all an easy thing to do - I would not be so bold as to try.
I have to take the recording as a given. I do not feel that it is right for me, as a loudspeaker designer, to try and correct the recording. If it is bad, then it should sound bad. A speaker is not about making everything sound good, it is about making them sound the way they were intended to sound, good or bad.
The thing is that THD and IM or Doppler are not different things. They are all just different reactions of the underlying system to the root cause, which is nonlinearity. So when I create a system that has THD it also has IMD if I use two signals to test it. So to say that you cannot hear THD but you can hear IMD I have to ask "How is that possible?" They cannot exist as separate entities. They both exist simultaneously. You cannot have a system with high THD but low IMD, it simply isn't possible. And visa-versa.
this is all interesting, but the topic was more about how, for example, Earl can play mids up to 1kHz XO, on a driver for which the manufacturer posts sub enclosure recommendations? 
I myself have zilch experience with large size drivers in mid applications (i.e. mine never got bigger than 8 inches), so I was looking for others to chime in. how about large size drivers declared for mid duty. Look at Precision Devices (or Fane) products, or any other for that matter, they all go lighter in the same size before recommending them for any vocals. we already heard a guy here say 75g was sort of a cut off point for him.
any other opinions based on personal experience? (read: you do not have to have measured data. no one in the field has yet sufficiently characterized psychoacoustics, or else people would not drag speakers to the shows, they would just mail you a brochure).
I myself have zilch experience with large size drivers in mid applications (i.e. mine never got bigger than 8 inches
), so I was looking for others to chime in. how about large size drivers declared for mid duty. Look at Precision Devices (or Fane) products, or any other for that matter, they all go lighter in the same size before recommending them for any vocals. we already heard a guy here say 75g was sort of a cut off point for him.any other opinions based on personal experience? (read: you do not have to have measured data. no one in the field has yet sufficiently characterized psychoacoustics, or else people would not drag speakers to the shows, they would just mail you a brochure).
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Not Earl, but I do. I've subjectively observed the same effect you discuss, but with concentric drivers played loudly. I think of it as a "nasal" coloration, but someone else could use a different word to describe the same sound. A friend of mine had the insight to measure the frequency response of a KEF Q100 concentric driver's tweeter with the cone ~3mm out and ~3mm in, and I bet what he found explains the issue:
An externally hosted image should be here but it was not working when we last tested it.
Source: medleysmusings.com
I would expect a similar dynamic to be in place with a whizzer cone driver.
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this is all interesting, but the topic was more about how, for example, Earl can play mids up to 1kHz XO, on a driver for which the manufacturer posts sub enclosure recommendations?
I have never crossed my 12 & 15" drivers as high as 1 kHz, but that isn't really the issue. The point is, if it works why not? because other people don't do it? because B&C (who have never designed loudspeaker system themselves) claim that it is a sub-woofer? I am missing the rational here. I showed you my data, but all I get back is "It doesn't sound good to me." That's not data.
Stan Lipshitz of Waterloo University did a study in AES some years back showing this same effect theoretically, so it is known to exist. But I have to admit that I would not have expected it to be as great as you show. How much excursion was done?
Retsel,
The "gargling" or "congested" sound occurs in vocal reproduction when low frequency tones cause the cone to exceed Xmax, the limit of linear excursion.
Excursion increases rapidly above and below box tuning, and quadruples each octave lower in sealed systems, X max can be exceeded on kick drum hits or bass notes.
As the loudspeaker excursion exceeds Xmax, the amount of voice coil that is within the magnetic gap decreases.
As the excessive cone movement reduces the amount of magnetic force controlling the voice coil, distortion increases radically.
To visualize what occurs in IM, think of a speaker playing 40 Hz and 400 Hz tones.
For each in and out motion the 40 Hz tone causes, the cone is also making 10 smaller in and out motions to produce the 400 Hz tone.
When the 40 Hz signal is strong enough to push the coil outside the gap (exceeds Xmax) the 400 Hz signal no longer is reproduced properly at the end of the inner and outer stroke.
The amplitude (SPL) of the 400 Hz tone is actually reduced at either end of the 40 Hz stroke, the period (length) of the 400 Hz amplitude distortion is modulated by the 40 Hz signal.
A lower low note makes for an longer modulation period, and our ears will notice more “gargling” if the modulation tone was 40 or 60 Hz than above 100 Hz.
The objectionable sound of IM/Doppler distortion in woofers may more accurately be described as "AM" distortion.
Anyway, your high pass got rid of the excursion problem.
Art
I don't know exactly. Here's how Erin described the procedure:
"To measure this performance I simply connected a 9v battery to the woofer’s terminals in positive polarity, then negative polarity which resulted in an approximate +/-3mm shift in cone direction. [note: woofer cone is about 120mm in diameter] I ran a sine sweep over the tweeter while the woofer was a) at rest, b) fixed out, and c) fixed in. The pictures below show illustrate this."
It is not arrogant if you are able to differentiate one thing from another.
I do not have to be a video engineer or expert in that field to see the difference between the image of the LCD vs LED TV and different technologies and approaches in that area. I don't know how it is that fluidness of motions is so much better in one of them but i can certainly see it quite well. Hearing is pretty much the same. If you can hear the difference that means that the difference is real regardless of an expert persuading you that there is none. Especially if one has had a chance to listen to a number of high quality audio systems and has a good reference point - as i do.
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Actually its not, but optical illusions still exist. Hearing is more prone is falsification that our visual sense although both can be fooled.
It has been shown on numerous occasions that the visual sense will override the hearing sense. We hear what our eyes tell us to hear, not what the sound actually is. It is a classic test in how easily the brain is manipulated.
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I know it can be done but i'm not trying to manipulate my brain, i am trying to keep it real. I do not care about the looks of the loudspeakers. What i do care is the sound of it.
The only thing that i can believe in is my objectivity. All i care about is the sound regardless of size, collor or any other feature of loudspeaker i am listening. I do not care if it is horn, waveguide, 1" dome, OB, bass reflex or any other loudspeaker type as long as it measures good and sounds good.
So if you are implying that my hearing is distorted or that if i hear the difference number of times on different occasions, the difference is not real - well i can't really say anything to that.
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What is the crossover frequency and slope rates of your speaker system(s) and with what size woofers?
this is all interesting, but the topic was more about how, for example, Earl can play mids up to 1kHz XO, on a driver for which the manufacturer posts sub enclosure recommendations?
I myself have zilch experience with large size drivers in mid applications (i.e. mine never got bigger than 8 inches
I stated 75gr as max for me and it is for 15" midbass. I have not tested 15" midbass with Mms under 107gr but i should do it in recent time so the 75gr is an assumption based on the comments of the guys that used some of the low cone mass 15" drivers. For 12" it would be arround 50gr and as low as possible for others. I did make loudspeakers and listened others with 12" that goes up to 1,5KHz and all of them that sounded good were with Mms under 50gr. The thing is that i did not know why are they sounding better - it is later that i wanted to see their TS parameters and measurements. So that excludes any willing or unwilling brain manipulation that might occure due to knowing any feature of that particular driver.
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All LP filters are 3rd order. The NS-15 is about 700 Hz, I believe, I am doing the NA-12 now and the Abbey is about 800 Hz. The woofer size is the model number - the Abbey is 12" as well.
I never look at the electrical filter characteristics so what I am quoting is the acoustical. Since both woofers have a subtle rise in response at the high end the electrical LP could be well below the acoustical one. The electrical one is necessarily a flat filter anywhere. Its is whatever works. It could be two staggered, different LP points - I suspect that they are.
The HP and LP are definitely not the same slopes.
You have an appropriate avatar then - the man with super powers.
Do yourself a favor and read "Thinking: Fast and Slow" by the Nobel Laureate Daniel Kanneman. Humans are incapable of being very objective and far worse than most people realize.
It turns out that the more objective one thinks that they are the less objective that they tend to be because they refuse to accept their own limitations and put full faith in themselves. That is not objective at all.
All in fun
, you will grow up just as we all do.on the subject of what makes for "an expert": what I particularly appreciate say about Siegfried L., is that you can see the evolution (progress) of the ideas over time. he was ready to change his position on a few occassions as he experimented and found out more about the sound reproduction, and was never afraid to go back and correct himself. he, and others, will always talk about functional trade offs as they are what engineering is all about; there is no "one size fits all" solution in sound reproduction (or anything else for that matter).
that's why: Earl, I believe I gave credit to your design where the credit was due and said enough positive things about it. Mind you, those were also based on subjective impressions, because if we relied on any particular piece of data as an ultimate "proof", every marketed product would be "perfect". the same goes for yours. so I do not see a problem in bringing up a valid question about your using the same driver in subs and for mid duty, at which, you even downplayed your own supplier's understanding of the product?
and I understand you are saying: "it works", and I agree that it does to a degree, but the clock did not stop when you came up with that design and no design is beyond a discussion. so please give other members here some courtesy. after all they share in the same passion even if they come of a biology background. we all have some credentials here but are not here to waive the banner of the infallible.
You have an appropriate avatar then - the man with super powers.
It is not a super power if you can practice it. There is a lot of personal effort involved into objectivity. I am not saying that i am fully there but i am pretty objective because i don't care about looks and i'm not into hifi for profit. I am in for the fun of it. I love German and Japanese cars (someone is going to kill me now
) and do not get into any "herds" (B&W, Dynaudio, JBL, Sonus Faber or any other herd ftm.). I love high eff speakers but listened to a more than a few low eff systems that sounded generally good. I do understand that hi eff is my preference so i think i am capable of determining what generally sounds good and what is better sounding to me as a matter of personal choice.If you make side by side listening test and one of the loudspeakers sounds better there is not much that can hold up anybody's bias.
P.S. - I do not put full faith in myself. I put full faith into measurements and myself (ear-brain combo in this case). One without the other is useless to me. I will read the book though. This kind of chitchat i enjoy more when done in person in a bar with a pint of dark beer and good music in the background
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