Neat Momentum 4i Iso-Baric?

I have been keeping an eye on them as they look interesting and have some good reviews. But very little info out there. And no one has been bidding on them. Started at a much higher price months ago. Could be a steal.

This goes back a long way, so I hope that I'm recalling correctly here....

As I understand the principle, Isobarics load a second - usually indentical - active driver behind the woofer, together in a separate sub-enclosure within the speaker cabinet. The idea is to keep constant pressure on the woofer as its (short) excursion takes it out past the baffle into the room and then back behind the baffle into the speaker cabinet. The second driver should reduce the "braking" (damping) effect of compressing the air in a smallish sealed box (acoustic suspension). Bass is said to be tighter than that typically produced by ported designs.

I recall hearing an old isobaric design from Linn way back in the day and feeling that the quality of bass was pretty good, but not really impressive in either power or extension for a speaker of that size. Of course, that was many, many years ago - so I have no idea what modern Isobaric designs can achieve.

Good Luck

Marty

Thanks for the replies, but the Momentum 4i are no longer listed. The listing doesn't even show up on a google search.

Isobaric also called compound loading is basically two woofers mounted front to front or front to back with a very small airspace between them wired so the the cones move in the same direction. Advantages are half the distortion and that the pair only need 1/2 the cabinet volume behind them to achieve the same bass output. Disadvantages are half the impedance and the fact that you need two woofers.

In my Montana EPX i use this technique, each box use 4 woofers, 4 ohm wired in series parallel for a combined impedance of 4 ohms - tremendous bass out put for a relatively modest sized floor stander.

As always, good listening

Peter

The NEATS are back on teh site.

Anyone heard them?