Thats not a real question, right? I measure every speaker that I make, I know each and every one of its flaws. There arn't many that can top that driver, but its not perfect either. Surprisingly, its biggest problem is not cone breakup. Its exception in that regard.
*If* you like to further discuss "stored energy" issues (as SL possibly has meant and measured it ig not purely min phase related) - I'm afraid you will have to face CMP behaviour as well - there is simply no other way around...
😉
Michael
😉
Michael
I could go on for days on this topic, but to make a very long story short - No. There are several papers on my web site on this topic if you want to read them ( Papers).
Joachim,
I'd say you are off on several points.
1) Soft dome's often break up BELOW their fundamental resonance, they do not have as such have a pistonic range.
2) The transfer function only remains flat if you apply enough avergaing and smoothing.
3) I have yet to hear any softdome I can actually put up with even short term. I also have yet to hear a hard dome I can put up with long term.
4) I do like ribbons, magnetostats and electrostats, which are also in essence operate in permanent breakup, as they have zero stiffness and without substantial smoothing the frequency response looks horribly non-flat (worse than unsmoothed soft domes).
5) The CSD and impulse response of Ribbons, Magnetostats, and electrostats (well designed ones anyway) shows rapid rise times and decay, in ways domes never do.
6) I have no clue what I am talking about, but I do not like speakers with domes.
Ciao T
I'd say you are off on several points.
1) Soft dome's often break up BELOW their fundamental resonance, they do not have as such have a pistonic range.
2) The transfer function only remains flat if you apply enough avergaing and smoothing.
3) I have yet to hear any softdome I can actually put up with even short term. I also have yet to hear a hard dome I can put up with long term.
4) I do like ribbons, magnetostats and electrostats, which are also in essence operate in permanent breakup, as they have zero stiffness and without substantial smoothing the frequency response looks horribly non-flat (worse than unsmoothed soft domes).
5) The CSD and impulse response of Ribbons, Magnetostats, and electrostats (well designed ones anyway) shows rapid rise times and decay, in ways domes never do.
6) I have no clue what I am talking about, but I do not like speakers with domes.
Ciao T
Thank you VERY MUCH.
You wouldn't believe how hard a google search is on "correlation, sound, harmonic, distortion" is to obtain meaninful results. Seriously. I've been going in circles for days. 🙄
I did find it interesting to see the large group of people who were extremely sensitive to distortion based on Klippel's method.
Configuration
However, the vast spread really makes it hard to say that X level of distortion is audble for the entire human race, and furthermore there's been no quantitative consensus on what each person who took the 'test' was running in regards to equipment.
It really makes me wonder if anything other than standard FR (and polars) and maybe CSDs (for resonance) supplemented by simple impedance sweeps is needed. IOW, it seems to me that HD levels may not be as important a test criteria as I thought. Especially since i've not been able to find any analysis or white papers strongly correlating THD to characteristics of a drivers "sound".
Additionally, I wonder just why we bother with THD at all? Is it simply a means of making sure the levels are below audibility threshold? Can we use the data to pinpoint specific 'problem areas'? IOW, since THD hasn't been shown to link 'sound' to the data, is the data still useful from a mechanical and ultimately acoustical POV (ie: resonance that becomes audible at x volume)?
Thanks again,
Erin
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I have not measured THD or IMD on any of my designs for years. I don't see it as relavent at all. There are lots of problems with loudspeakers, but they are all linear. (Don't ignore those effects that have nonlinear perceptions however.)
These are some highlights I pulled from your papers (in your own words):
- Nonlinear distortion in a loudspeaker does not appear to be a strong factor in its perception. This means that these effects are more audible at higher SPL levels than lower ones.**
- This is in stark contrast to the audibility of nonlinear distortion which is less at higher SPL levelsThis means that these effects are more audible at higher SPL levels than lower ones.
- This is in stark contrast to the audibility of nonlinear distortion which is less at higher SPL levels
- It is the perceived sound quality that matters not the measured quality – unless that measurement has been scaled and correlated to subjective perception through valid psychoacoustic tests.
- In a completed system, with competent drivers, the high level sound quality is more likely to be limited by cabinet diffraction or similar effects than by driver nonlinearities.
It seems to me what you're saying is the THD/IMD measurements are less important than the end product's result itself since the final build's effect has mor einfluence on the sound characteristics we hear (ie: baffle diffraction).
I hate to think the THD results are meaningless, however. I guess at this point, I'm trying to make them useful in my regard to comparitive analysis. I plan to test many drivers on X baffle with X criteria, where the end goal is simple comparitive results; not absolute. It seems to me that comparing THD results may be useful in regards to picking crossover points, etc, especially if the distortion levels near audibility. Or am I completely off base here?
**In regards to the first bullet above, is masking linked to the equal loudness curve or is masking a way of relating how much sound is going on thus resulting in more 'stuff' being thrown at the listener (which, still to me relates to the equal loudness curve)?
If these questions should be asked outside of this thread, please let me know.
Thanks,
Erin
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If those quotes are right, maybe they are out of context, because they don't read right now.
1)"These effects" would have to mean diffraction, because nonlinear distortion would become less audible, at a constant %, at higher SPLs than lower ones.
Masking and Loudness are really completely different things, pretty much unrealted to each other. Masking is a key principle in the understanding of "perception". I am sure that Wiki must have a write-up on it.
I simply do not see THD being of much use in anything in loudspeakers. I haven't looked at it for years. The only thing that I check for nonlinearities are amps - and then only at very low levels
1)"These effects" would have to mean diffraction, because nonlinear distortion would become less audible, at a constant %, at higher SPLs than lower ones.
Masking and Loudness are really completely different things, pretty much unrealted to each other. Masking is a key principle in the understanding of "perception". I am sure that Wiki must have a write-up on it.
I simply do not see THD being of much use in anything in loudspeakers. I haven't looked at it for years. The only thing that I check for nonlinearities are amps - and then only at very low levels
It is a matter of degree, you may not be completely lost and there is no consensus that speakers are linier. Speakers do produce nonlinear distortion. To some degree a level of distortion is acceptable, even preferable to some.
Impulse tests and the subsequent waterfall plots have ridges and valleys that show distortion in both frequency and time.
I would venture that if you do waterfall plots on your speakers besides being pleasing to the ear they will have prominent ridges and valleys in the MLS plots.
DT
All just for fun!
True, but it does not fully operate in piston mode either, at least not within 20db of it's pass band.
I think the issue is not really whether it's best to operate within the piston mode or not, but rather the best way to use a driver. Purely using the piston mode may not be the best trade-off from a system point of view. From a directivity point of view, piston mode is actually not so ideal. I'm sure you know this, otherwise you would not have used the current design you have for the Summa, etc.
For the ZDL type design, how the baffle edge should be designed would strongly depend on the bandwidth of each individual driver as used in the system. The diffraction control requirements at different angles is also very important.
Good thing you guys stood out.
If Michael keeps advertising the "term", I just have to butt it until he points out what is new.
Thorsten, I'm with you on most of the points. I tried a Beston ribbon with 3" drivers. Started crossing them in around 3KHz, and ended up crossing them in about 10KHz. The results were quite amazing, as also indicated by the other audiophiles I demonstrated it to. Of course, this was exactly in proportion with how fast they decayed. The reason of raising the XO point was to find that sweet spot that provides the required dynamics, and the sound quality.
I've spend a fair bit of my time measuring distortion parameters over the years and have come to many of the same conclusion as Earl. If a driver is operating in it's operating range, you usually cannot "hear" nonlinearites. They have to be fairly severe to be heard. That's not to say they aren't important from a design standpoint, or even a theoretical standpoint. After all, it cannot be argued that less nonlinear distortion is better from a theoretical/technical standpoint.
From an engineering standpoint, if you design your system such that the drivers are well in their operating range, you won't hear a difference based on whether the 5th harmonic is -60 vs -65 etc etc.
On the flip side, many systems, especially 2 way systems that are commonly designed, when played loud, are being pushed somewhat beyond their design specs, and here the distortion can be picked up. It can be useful to know how low I can push a tweeter, for example. (If I'm using and "inferior" non compression one...😉
I've always said that I can design a system where distortion is a problem (and there are a lot like that) and I can design a system where it is irrelavent. I prefer to do the later. The lunacy comes in thinking that a 1% THD speaker sounds better than a 2% one.
By operating range, are you meaning limiting it to pure piston behavior?
And Dr Geddes, your non linear distortion in amps...we are talking about crossover distortion there? If so I could understand why that would be more important to you than it would be in speakers seeing your speakers are a good 12-15 dB more efficient than the "typical" home speaker system.
And Dr Geddes, your non linear distortion in amps...we are talking about crossover distortion there? If so I could understand why that would be more important to you than it would be in speakers seeing your speakers are a good 12-15 dB more efficient than the "typical" home speaker system.
Yes - you can !
No - you can not !
If you read what I linked you possibly may have understood to what extend each part of above contradictional statements apply.
Beeing a (novice) fan of impulse response shaping at will – you may further have understood the implications of CMP concept with respect to brick wall limitations of advanced EQing.
🙂
So - its not a question if I'm "advertising" CMP - its the question to what degree you are capable to understand - and willing to accept - CMP implications
😀
Cone break up certainly is CMP related – but – dependig on shape, dampening and time slot looked at - its not as dead easy to grasp / analyse / understand as CMP effects of open baffle or compound bass (piston behaviour assumed)
Michael
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You can prove you understand what's going on when you show measurable results that you can improve it's effects by 10db. Until then, you cannot prove you understand anything. Just a simple, before solution, and after solution comparison would do.
Interesting but hard to understand thread not really relevant to the design.
Continuing the irrelevance, the latest theory on the extreme damage caused by the Christchurch earthquake is that the wave traveling towards the seaward side of the island were reflected by the extremely hard basalt of the port hills, combined with the waves traveling inwards to wards the city to make larger and small waves and perhaps a comb or lobing effect which is said to account for why some areas got off virtually scott free and others were damaged out of proportion to what would be expected. It was also suggested in the same article that this same unknown fault may have been jammed under enormous pressure for over a thousand years and then suddenly released. Is this stored energy. Members of my7 family were effected by this one but all survived and OK thank God.
jamikl
Continuing the irrelevance, the latest theory on the extreme damage caused by the Christchurch earthquake is that the wave traveling towards the seaward side of the island were reflected by the extremely hard basalt of the port hills, combined with the waves traveling inwards to wards the city to make larger and small waves and perhaps a comb or lobing effect which is said to account for why some areas got off virtually scott free and others were damaged out of proportion to what would be expected. It was also suggested in the same article that this same unknown fault may have been jammed under enormous pressure for over a thousand years and then suddenly released. Is this stored energy. Members of my7 family were effected by this one but all survived and OK thank God.
jamikl
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