Why not acoustic suspension?

@dynamiclinearity  After this thread sparked my memory about those old speakers, which i thought, in my youth, were just white van speakers, I went googling and realized that what I actually owned were the ESS-made Cannon TLS 1030's. 😭

Hi Erik. I've cited this before. The most famous small closed box speaker is the BBC LS3/5a and it is NOT acoustic suspension. Acoustic suspension speakers tend to be small because it does relate to how they work but small doesn't mean acoustic suspension.

Sealed boxes really sound boxy when used for home theater, especially with dialog. You can test by plugging the center channel or the mains if you use phantom center. I haven't tested it for music but I'd imagine it's the same.

There are 2 critical components in an Acoustic Suspension speaker 1) a truely sealed box 2) a woofer that is essentially floppy and unable to operate correctly in free air.  The spider and suspension of an AS woofer are extremely compliant, and the woofer cone will essentially "ring" following the signal.  The woofer design requires the fixed volume of air in the cabinet to add a damping force to the woofer while in use.  The cabinet is fully sealed (non leaking), and the air compresses as the woofer receives signal.  The amount of air compression and force with which it pushes back to restore a pressure balance in the cabinet can be calculated, and then used to damp woofer motion and prevent ringing or distortion.  An AS woofer can reach very deep, with shockingly low amounts of distortion.  The offset is low efficiency, and a requirement for a lot of power to get the best from the woofers.  AS speakers are typically paired with higher powered amplifiers compared to a ported design.

Non AS designs include closed boxed, or infinate baffle designs- Bozak speakers are infinate baffle.  The box may be sealed, but the woofer will also work quite well in free air, and does not need the restorative force of the internal air volume to produce distortion free bass.

The LS3/5a box is lossy....while it appears sealed, some air does escape from the joints between sections of wood.

Ported designs are more efficient, so they can play louder with less power.  Ported designs can be made to deliver acceptable bass response (not as deep in general as AS designs), but in a smaller cabinet.   One can use off the shelf components instead of requireing custom designed drivers.  All of this translates to a manufacturing cost.

With the trends favoring vintage or vintage inspired designs, I am surprised that only KLH has introduced AS design speakers.  They have been well received, and by all accounts sound wonderful.

With the trends favoring vintage or vintage inspired designs, I am surprised that only KLH has introduced AS design speakers.

Guess Magico, ATC and YG have ceased to exist