Except... large excursion is ALWAYS BAD for sound quality. For a number of reasons, among which: non-linearity in suspension, back-EMF proportional to displacement, etc.
To obtain a target SPL at a given frequency, the required volume displacement should be obtained by maximising Sd, not Xmax.
The old adage "if you can clearly see the diaphragm moving, then it's distorting" still applies.
To obtain a target SPL at a given frequency, the required volume displacement should be obtained by maximising Sd, not Xmax.
The old adage "if you can clearly see the diaphragm moving, then it's distorting" still applies.
Based on the Sd, the estimated cone diameter is 157mm. What is that? A 6.2" driver? or a 7.2" driver?
Sadly there is no standard size.
@marco_gea
Sure. But not everybody has space or a wants a 21+" bass horn subwoofer + 4 way loudspeaker in their home. So if you can't maximise Vd(x), then minimising BL(x), Kms(x), Le(x) and Sd(x) is a worthwhile endeavor.
Sadly there is no standard size.
@marco_gea
Sure. But not everybody has space or a wants a 21+" bass horn subwoofer + 4 way loudspeaker in their home. So if you can't maximise Vd(x), then minimising BL(x), Kms(x), Le(x) and Sd(x) is a worthwhile endeavor.
Everything is fluent in speaker design ... large cones have lower upper limits! Cabinet has more structural problems ... it all depends on your design goals!
The large excursion Scan Speak 7inch underhung driver has a broad 2dB dip between 200 and 800Hz due to excessive uncompensated coil inductivity (copper ring/motor) ... a potential weakness for the final sound of a passive speaker or a too fat sound depending design decisions .
Distortion? Well read or ask PURIFY , they have virtually eliminated DISTORTION at all!
Of course you could use FOUR 8 inch distortion purifiers from denmark instead of ONE oldcone-oldstyle-oldspeaker-oldertime-wondercone implimentation of your dreams
Too Many Choices is a real problem in speaker design , once you get infected by this TMC-virus , you'll never get cured
The large excursion Scan Speak 7inch underhung driver has a broad 2dB dip between 200 and 800Hz due to excessive uncompensated coil inductivity (copper ring/motor) ... a potential weakness for the final sound of a passive speaker or a too fat sound depending design decisions .
Distortion? Well read or ask PURIFY , they have virtually eliminated DISTORTION at all!
Of course you could use FOUR 8 inch distortion purifiers from denmark instead of ONE oldcone-oldstyle-oldspeaker-oldertime-wondercone implimentation of your dreams
Too Many Choices is a real problem in speaker design , once you get infected by this TMC-virus , you'll never get cured
Without taking anything whatsoever away from Purifi -they have not 'virtually eliminated distortion'. The drivers certainly are low distortion for their size / type, and very good they are too -but it still exists. As measured by Yevgeniy: https://hificompass.com/en/speakers/measurements/purifi/purifi-ptt65w04-01a
What matters is SD and not the basket outer diameter. SD of these Kartesians is 193 cm2, a typical 6,5" driver has 130-140 cm2, a typical 8" has 220-230 cm2.
Exactly, "for their size".
Take most well-designed (i.e., not dirt cheap) 15" woofers and, at the same target SPL, the distortion will be WAY LOWER.
Lemme adjust your taste : THE MOST SEXIEST WOOFER ALIVE !!!
Summore stuff to crunch on your lowspeed biocomps :
https://www-homecinema--fr-com.tran..._sl=fr&_x_tr_tl=en&_x_tr_hl=de&_x_tr_pto=wapp
Summore stuff to crunch on your lowspeed biocomps :
https://www-homecinema--fr-com.tran..._sl=fr&_x_tr_tl=en&_x_tr_hl=de&_x_tr_pto=wapp
Almost certainly, assuming quality design, but on principle I'm a fan of 15in - 16in HE woofers and have been for years (preferably of the vintage Altec persuasion -which sadly my wallet doesn't extend to), so 'no news [but definite agreement when space permits] there'.
Last edited:
No thanks. 'Woofer' and 'sex[y]' are not words I usually put together.
With Emilia Clarke, Sophie Ellis-Bextor etc., very definitely. I can't say I feel molten passion for a lump of metal, deep profile cone & a ring magnet, but different strokes for different folks, as they say...
Last edited:
Regarding distortion , years ago I found a research PDF on the web (maybe AES society) stating the self-distortion of the human ear around 90dB is 1-2% and has a falling but irregular distribution for harmonics up to k5!
Earl Geddes (gedlee.com) should know that fact but I do not remember stating this by him in all the years he was active in so many discussions! (makes me wonder why)
The discussion about distortion is somewhat misleading , an acoustic bass has typically a k2 of 50% (spectrum analyser like Audacity or Goldwave) , for instance check Lady d' Arbanville by Cat Stevens ... how could you detect 1% more distortion if the "signal" itself is quite a lot "distorted"?
Btw my earspeakers Stax Lambda pro comes with a printed measurement of the manufacturer showing 0.1 - 0.3 % distortion (k2/k3) for the whole audio band , but at 120dB !!
So to me it's very strange to talk much about distortion but no one seem to realise what we already have as a reference since the late eighties! Is the audio biz totally mad or do we have a massive case of hidden corruption here?
Sorry for the bad news but you can't fool all the people all of the time! (Peter Tosh/Wailers , R.I.P.)
regards , The DIY Detective
Earl Geddes (gedlee.com) should know that fact but I do not remember stating this by him in all the years he was active in so many discussions! (makes me wonder why)
The discussion about distortion is somewhat misleading , an acoustic bass has typically a k2 of 50% (spectrum analyser like Audacity or Goldwave) , for instance check Lady d' Arbanville by Cat Stevens ... how could you detect 1% more distortion if the "signal" itself is quite a lot "distorted"?
Btw my earspeakers Stax Lambda pro comes with a printed measurement of the manufacturer showing 0.1 - 0.3 % distortion (k2/k3) for the whole audio band , but at 120dB !!
So to me it's very strange to talk much about distortion but no one seem to realise what we already have as a reference since the late eighties! Is the audio biz totally mad or do we have a massive case of hidden corruption here?
Sorry for the bad news but you can't fool all the people all of the time! (Peter Tosh/Wailers , R.I.P.)
regards , The DIY Detective
I might postulate that relative phase and harmonic distribution of the distortion being added to the recording of the instrument or other sounds might make the difference detectable. Instruments are made up of harmonics, sidebands, beats and resonances, but if adding or subtracting something that is uncommon in that natural sound, it might be noticeable once it reaches a certain magnitude. It can be assumed this is why some loudspeakers sound better or worse than others. It’s a topic entirely in itself and can be quite interesting.
About the woofers, I usually don’t complain about this type of thing, but those prices are excessive. It’s as though +$1000 drivers have become soup du jour in DIY.
The attraction to a smaller size woofer is understandable, but I don’t see any technology to avoid the increase in modulation distortion as diaphragm excursion increases. The doppler effect on higher frequencies is going to be audible at those Xmax levels, and it might even be assumed there will be someone, somewhere who will DSP the response to take advantage of the higher excursion capability for low-frequency extension. That seems to be what users are doing with Purifi drivers.
About the woofers, I usually don’t complain about this type of thing, but those prices are excessive. It’s as though +$1000 drivers have become soup du jour in DIY.
The attraction to a smaller size woofer is understandable, but I don’t see any technology to avoid the increase in modulation distortion as diaphragm excursion increases. The doppler effect on higher frequencies is going to be audible at those Xmax levels, and it might even be assumed there will be someone, somewhere who will DSP the response to take advantage of the higher excursion capability for low-frequency extension. That seems to be what users are doing with Purifi drivers.
Luckily there is plenty of music with tons of "distortions" that gives you everything you need to enjoy every second of the audio massage of your brain and you will forget anything else , short listen examples :
https://www.jpc.de/jpcng/poprock/de...t-of-singles-and-12-inch-version/hnum/5148131
Track 1 - first CD , when the bass and drum comes in , any discussion about distortion numbers turns to dust!
Sound quality is excellent for this CD release and interesting to recognize what has been fine tuned in arrangment and sound balance plus adding effects in a half-dozen versions of the same song!
Singers voice is remarkable on this song , guess its real hard to find someone whos able to Catch Up
ps .. "I found out having wasted too much time now washing away the tears" ... yes my dear you have used THE WRONG STUFF to feed your ears!
https://www.jpc.de/jpcng/poprock/de...t-of-singles-and-12-inch-version/hnum/5148131
Track 1 - first CD , when the bass and drum comes in , any discussion about distortion numbers turns to dust!
Sound quality is excellent for this CD release and interesting to recognize what has been fine tuned in arrangment and sound balance plus adding effects in a half-dozen versions of the same song!
Singers voice is remarkable on this song , guess its real hard to find someone whos able to Catch Up
ps .. "I found out having wasted too much time now washing away the tears" ... yes my dear you have used THE WRONG STUFF to feed your ears!
No need for new stuff if the old stuff is far much better than your dearest dreams :
This tune is from 1971(!) .... no computers at all!
That's why I am building my own loudspeakers where no other decides what is important and what not! Sorta pure capitalism/macho territory and I LOVE it
This tune is from 1971(!) .... no computers at all!
That's why I am building my own loudspeakers where no other decides what is important and what not! Sorta pure capitalism/macho territory and I LOVE it
Ehm well, I think you missed a bit of a very important note here.
Companies like Kartesian or Purifi (there are many others) actually focus on having extremely low nonlinearities.
Meaning minimizing things like back-EMF, non-lineair behavior in BL(x), Kms(x), Le(x).
Exactly like @tktran303 said.
So as a general rule, what you're saying is right, but pointing that out for these particular speakers is a bit of using the wrong example. These kind of speakers often compare pretty well to a size bigger.
That being said, everything is relative obviously.
In a case and context that someone has money to spend, needs to compromise is total size and volume, these kind of drivers are great.
In many other situations not so much, because a slightly bigger other woofer or two other woofers will probably perform very similar. But not everyone is able to fit a 15 inch in his/her room.
Also, there is only so much SPL you can get out of these (see it as an extremely well performing 25W amplifier).
Personally, seen the price, I think it's a hard one to swallow, I can come up with so many other solutions for that price.
I think the quantities they are making are just extremely low.
It's unfortunately, I have been in contact with them a few times on a professional level.
They seem really great people, wanting the right thing in the world of loudspeakers.
But these kind of prices are extremely hard to sell or use for projects when there are so many other alternatives (often cheaper).
Looking and comparing several 3rd party measurements, they are doing well, but I would most definitely not quantify it as eliminating distortion at all!
In mid-range there are many other alternatives, similar size or otherwise 8 inch or 10 inch, that perform similar or even better.
For low-range there are tons of options available that perform way better.
There are only very few options that are great at both.
But a full-range system is way to much of a compromise for me compared to a (very simple) multi-sub system.
So the fact that it's great at both is bit of a useless case imo, especially for that money.
Last edited:
[virtually eliminated DISTORTION]
Hello ... the magic word here is : HEARING THRESHOLD (for distortions)
Numbers become meaningless if the distortion products are very low , the masking effect works usually very well .... so my statement was meant in context from a higher complex perspective!
And - making judgements about speaker sound quality in ordinary rooms makes not much sense too ....
Hello ... the magic word here is : HEARING THRESHOLD (for distortions)
Numbers become meaningless if the distortion products are very low , the masking effect works usually very well .... so my statement was meant in context from a higher complex perspective!
And - making judgements about speaker sound quality in ordinary rooms makes not much sense too ....