Obviously, i did not read it correctly. Why are woofers pointing to the right, when midbass, upper mid and tweeter are pointing forward? Why? Just to confuse? You know, i do not care. I posted my opinions, good luck.
Isobaric cone to cone and magnet to magnet alignments have also some advantages.
First is distortion cancellation, second is lower Fs and Qts caused by air mass between cones.
First is distortion cancellation, second is lower Fs and Qts caused by air mass between cones.
Reduction in second,mincrease in third. Not always a good trade-off. And if you have good woofers it makes no difference.
Something about one of the arrangements, slanted or straight. Ideally the volume of air in the chamber should act as a slug. Volume as small as possible.
dave
Dual opposed looks a way better design to me, they need double the amount of air in the enclosure compared to a single driver.
But if a single driver needs 40 liter give the DOS 30 liter each, with low fs 17hz and qts 0.32 drivers (scanspeak discovery subwoofers) its not a big problem.
And even in 30 liter the 2 drivers wil easy outperform a single sub with 5db or so
you need also double the power for best results plus 5-6db, but even with the same power it plays 2-3db louder then the single in 40 liter.
But if a single driver needs 40 liter give the DOS 30 liter each, with low fs 17hz and qts 0.32 drivers (scanspeak discovery subwoofers) its not a big problem.
And even in 30 liter the 2 drivers wil easy outperform a single sub with 5db or so
you need also double the power for best results plus 5-6db, but even with the same power it plays 2-3db louder then the single in 40 liter.
Well, I personally have no experience with Isobaric principle. I know that it is also used in Subwoofer systems too, as most of the litterature you find on the web deals with that... Very few information online seems to be available about the use as a woofer section of enclosures.
* Some companies used / still use the Isobaric principle in their enclosures on some models : SIARE (FR), LINN (UK), MonAcoustics (USA)...
* Vance Dickason in "Loudspeakers CookBook" states :
- QTS is the same.
- FS is the same.
- VAS is halved.
- Efficiency is the same.
- FS of the whole system is typically divided by root of 2.
- Transients are improved by the Isobaric air effect, at least until 150 to 300Hz.
- internal resonances of the enclosure are tamed by the isobaric chamber.
- power handling is doubled.
T
"Transients are improved by the Isobaric air effect...". Now that is something I would like to see measured!
Yes. This is what is told... But unfortunately, I did not found any studies about the subject ! 😕
T
I see @Palmspar - thanks !
That said - if I read correctly the description of the ARENDAL 1723 above - it seems that it is a "push-push" (in-phase speakers) disposition in a ported Bass-Reflex enclosure, not a "push-pull" (reverse phase speakers) Isobaric sealed construction. So it's a different "Animal", if I can say so ! 😉
T
Hi Nico,
WTH is this. I just brought home this one, it is far less analytical than my usual speakers, bu it is soo warm and good to my ears. What are those?
Apparently, the original KEF Concerto were not of the Isobaric type, but classic BR enclosures, conversely to what Nico Ras posted :
T
They look similar, but mine are transmission line, Concerto is BR as just mentioned above.
I removed B139, Inside is original Xo Kef SP1004 and B139 is SP1044 with date from 1975 🙂.
But I dont want to hijack this tread, these are not Isobaric speakers neither
Or A Fried R without the damping in the vent.
Lots of ways to improve that loudspeaker, particularly if using KEF’s XO.
dave
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Hi Dave,
Once I start to rebuilt these it will be new tread, and then I will surely try to tap on your knowledge.
For the moment, do you know where is the best to get rubber suspensions got B110? On one speaker there is small crack in rubber, not significant but I like to restore those .
Once I start to rebuilt these it will be new tread, and then I will surely try to tap on your knowledge.
For the moment, do you know where is the best to get rubber suspensions got B110? On one speaker there is small crack in rubber, not significant but I like to restore those .
PS, whats that ?