Distortion measurements on loudspeakers _ do they tell anything of value?

[ginetto61]

Driver's Xmax (voice coil overhang) exceeding will not result in clipping, but distortion (nonlinearity of vibration) skyrockets. Coil/magnet constuction is important and there are many ways to reduce distortion near and beyond Xmax (eg. copper ring)

thanks a lot again I suspected that Now i have a very important confirmation
i have really to study more But i feel i am on the right track
i have never looked at Xmax before Now it has become an obsession

Xmech is often much higher and then behaviour is like clipping of an amplifier. Every loudspeaker driver behaves a little differently, some will break from first hit, some other can take it for some time. Testing of this will get very expensive...

thanks again. I will go to the thread you kindly mention
the very important conclusion is that the Xmax constant curve in terms of SPL vs Hz will provide a kind of good operation area for a driver
above that curve the behaviour of the driver will become not linear with all the nasty consequences
in an ideal world for lazy persons the manufacturers would provide that curve already in the datasheets
in any case i would love to measure it before using a driver

I'm using a 4" woofer driver, which according to its manufacturer has a +/- 3 mm maximum excursion (Xmax).
I also use a DSP for this driver which has a limiter that I could use to limit the maximum excursion in accordance with the above specs.
My concern is, could it be safe for the driver to set the limit at a higher excursion, for example +/-5 mm, if the higher distortion is accepted.
Any experience on this issue?

this i do not understand Why not change driver ? why pushing one above its natural limits ? why not using two in parallel ?
usually when parts are used within their safe operation area sound better and last longer

 

[Juhazi]

Xmax and Fs etc. motor behaviour explain most of low end distortion and spl response
Cone, surround and spider explain most of upper band problems

If you want to measure Xmax yourself, please read the Klippel papers well.g.
And perhaps buy their test equipment and software, 7500€ plus taxes.https://www.klippel.de/products/qc-system/features/comprehensive-testin

 

[ginetto61]

😱 i would try the sim SW first to get an idea of the drivers behaviour 🙂👍

 

[audiomot]

All a speaker has to do is sound good. Your ears are the best measuring instruments to tell you which speaker "sounds the best." Why? Speakers come in all kinds of "flavors." You will need to dial in which strengths and weaknesses you want in your speaker.

I think everybody should consider the technical specifications and verify that interface between the amplifier and the speaker makes sense. As in is the amplifier up to the job of driving the speaker properly?

 

[ginetto61]

All a speaker has to do is sound good. Your ears are the best measuring instruments to tell you which speaker "sounds the best." Why? Speakers come in all kinds of "flavors." You will need to dial in which strengths and weaknesses you want in your speaker.

Hi and thanks for the kind advice I am most interested in speakers without measurable flaws like bad FR or dirty CSD and so on
Now i have also learnt about Xmax another very important parameter to pay attention to
I alway love to quote the very meaningful words of a great audio designer

DAL firmly believes that a full set of credible measurements, made by qualified engineering staff using state-of-the-art equipment and facilities, can reliably predict the potential of a loudspeaker to accurately reproduce the complex sounds of music."—Dunlavy Audio Labs

I think everybody should consider the technical specifications and verify that interface between the amplifier and the speaker makes sense. As in is the amplifier up to the job of driving the speaker properly?

i will address the amp later I am thinking to get a 2 ohm stable amp with some current at the output
i was convinced about the paramount importance in an audio chain of the speakers by this article about a blind test

https://www.matrixhifi.com/ENG_ppec.htm

same speakers different amps similar sound For me this has been like a Copernican revolution

 

[kgrlee]

i was convinced about the paramount importance in an audio chain of the speakers by this article about a blind test
https://www.matrixhifi.com/ENG_ppec.htm

This is a good test. I have some reservations but I'll deal with two.

"each listener/tester could use the music of his choice." This is a MUST. Playing classical music to a heavy metal fan will make his results random. But if you let him choose his music, he will pick/like the same speakers as the classical recording engineer.

"we have gone from the usual DBT questioning "wich is the one"? to "wich one you like best"?" We always do this.

There is MUCH more to say but ...

We do ABC tests rather than ABX as we get statistical significance much faster.

Test only ONE person at a time.

 

[ginetto61]

This is a good test. I have some reservations but I'll deal with two.

good morning and thank you for your precious answer
a little premise I started to get passionate about hifi in 1975
and I became an avid reader of UK magazines like hifi choice and what hifi
in particular hifi choice used to test different amps with the same speakers and the declared differences were quite remarkable
so I always thought that an amplifier could indeed make a difference
instead lately these blind tests have put my beliefs into crisis
for example in another test a very expensive hifi amplifier and a cheap PA amplifier with everything else being equal gave very similar results
in short I am dedicating myself to better understanding the speakers with the aim of putting together a decent 3-way

"each listener/tester could use the music of his choice." This is a MUST. Playing classical music to a heavy metal fan will make his results random. But if you let him choose his music, he will pick/like the same speakers as the classical recording engineer.

very interesting This means that a better speaker is better with any music Very good

"we have gone from the usual DBT questioning "wich is the one"? to "wich one you like best"?" We always do this.

in the end the listening pleasure is always the goal Good to know

There is MUCH more to say but ...
We do ABC tests rather than ABX as we get statistical significance much faster.
Test only ONE person at a time.

thanks again sometimes i read lines that leaves me puzzled like these ones

https://www.theabsolutesound.com/articles/tas-legacy-bowers-wilkins-801-loudspeaker/

Introduced in 1980, the B&W 801 almost overnight became the speaker for top-shelf recording studios and mastering suites. EMI, which later became Abbey Road, adopted the 801 as its reference monitor. Many other studios followed suit.

then i read about some distortion issues from the mid when the speaker is pushed a little with the cause being a too low xover point between woofer and mid
how is possible that a flawed speaker pleases so much professional recording engineers to become a classic in recording studio of such music labels ? are they deaf ?
it would be extremely helpful to assess these distortion issues with the help of measurements
now i have a key parameters and a rule
Never exceed the Xmax of a driver
a small step for an expert speaker designer a giant leap for gino
Thanks again and have a nice day
gino 🙂👍

 

[ginetto61]

Hi i just would like to link a video where the diaphragm size and excursion are put in relation to the SPL achievable
it is shocking to see how very low bass require many very big drivers