Well reading through my Great sound stereo speaker manual (good book for novices by the way) I saw the isobarik config and it seems to have good qualities. It looks like it allows a fairly uniform pressure on the outside driver while the inside driver has a big space behind it to soak up displacement. I know alot of poeple look at this as a low freq application, but could this work well with say 4" tang bands? And I would definently be doing the format where the driver behind is facing the outer drivers magnet, since clamshelling would not work so well for full range 
Also on a side note, what do you think of Aperiodic enclosures, they seem like a the best of sealed and ported. This is another possiblty I'm thinking about.
Also on a side note, what do you think of Aperiodic enclosures, they seem like a the best of sealed and ported. This is another possiblty I'm thinking about.
Isobaric (k) loading..
..will be no use for small drivers like the Tangbands.
The main advtantage of Isobaric loading is to use drivers that would require a really big cabinet to be used in a cabinet of half the volume. If you are using isobaric loading in a two way or less, then the bass driver will have to operate at a high enough frequency that the rear driver will be interfering with operation. You need to low pass the rear driver at a low frequency (for a three way, front and rear driver can be low passed at the same low frequency.)
The other advantage of isobaric is like double glazing. Less sound reflection from the cabinet gets through the two woofers.
I wouldn't consider isobaric loading on anything below an 8" driver, probably larger with todays drivers.
..will be no use for small drivers like the Tangbands.
The main advtantage of Isobaric loading is to use drivers that would require a really big cabinet to be used in a cabinet of half the volume. If you are using isobaric loading in a two way or less, then the bass driver will have to operate at a high enough frequency that the rear driver will be interfering with operation. You need to low pass the rear driver at a low frequency (for a three way, front and rear driver can be low passed at the same low frequency.)
The other advantage of isobaric is like double glazing. Less sound reflection from the cabinet gets through the two woofers.
I wouldn't consider isobaric loading on anything below an 8" driver, probably larger with todays drivers.
Re: Isobaric (k) loading..
What Richard says covers off most of it. Isobariks were a favorite of mine for sometime.
What happens when drivers are isobariked at high frequencies is that as the reproduced frequencies approach the dimension of the 1st enclosure you get a dip in the response.
The comment about double glazing is often missed when people talk isobarik -- it can be a significant positive benefit in terms of removing the box signature from the sound.
All that said one of the most enjoyable speakers i ever built -- midrange dip & all -- was a set of isobarik MTMs with 4 KEF B110s & a T27.
Now-a-days i use two drivers in a push-push configuration, which besides helping to eliminate the box from the equation has other positive benefits.
dave
Now-a-days
RichardN said:
What Richard says covers off most of it. Isobariks were a favorite of mine for sometime.
What happens when drivers are isobariked at high frequencies is that as the reproduced frequencies approach the dimension of the 1st enclosure you get a dip in the response.
The comment about double glazing is often missed when people talk isobarik -- it can be a significant positive benefit in terms of removing the box signature from the sound.
All that said one of the most enjoyable speakers i ever built -- midrange dip & all -- was a set of isobarik MTMs with 4 KEF B110s & a T27.
Now-a-days i use two drivers in a push-push configuration, which besides helping to eliminate the box from the equation has other positive benefits.
dave
Now-a-days
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