Why not acoustic suspension?

Magico speakers are closed box. I'm not sure if they are acoustic suspension although I think they claim it. But I suspect they are not.

Sonically, you can tune any closed box to a given transfer function, closed box or acoustic suspension. The advantage of acoustic suspension is smaller boxes but at the price of lower efficiency. What may have been especially important about acoustic suspension is the smaller box because stereo and acoustic suspension came about the same time. And the smaller boxes made two speakers more acceptable.

One problem that was basically ignored when acoustic suspension first came out was efficiency. The tube amps of the day were underpowered(the super popular Dynaco Stereo 70 was rated at 35 watts optimistically and 50/60 watts was a big deal) for acoustic suspension so they were never heard at their best. When we finally got good, high power amps it was too late and bass reflex had taken over.

As to bass response. The knee point(-3 dB) is usually lower for bass reflex than closed box. So for most music bass reflex sounds bassier. However reflex rolls off faster and deep down closed box, while reduced in bass, takes over. Plus and I think most important a great closed box is more accurate in bass quality(less bass overhang) than a great bass reflex speaker. The problem seems to be that most listeners like the bassier sound of extra overhang perhaps because we're used to it since reflex rules.

It is for posts like this that I keep coming back to Audiogon! Great discussion, learned several things about the two sets of vintage acoustic speakers I own, KLH Model 17 with up-graded tweeters, and a mixed pair of AR-2’s (one = 3-way AR-2ax; one = 2-way AR-2a). The 3-way sounds much better to me. The plan is to convert the AR-2a to an AR-2ax, but that will mean replacing the baffle in the AR-2a. 

I’ve used this acoustic suspension/sealed speaker- Opera Seconda off and on for 15 years.

Currently use ESL’s.

Convincing/impactful bass at all volume levels. 2 REL subs used for full immersion. A poor mans Sonus Faber-Italian, beautiful veneer/leather. I use tube power.

I am still enjoying my vintage pair of AR-2ax speakers, owned since the late 1960's!  They have the impregnated cloth woofer surrounds, which did not deteriorate like the foam surrounds that AR used in later production runs in the 1970's. 

I did have to replace the corroded level controls, a single mid-range and a single dome tweeter - but these 10 inch woofers have survived all these years, and still sound great.  They really shine when reproducing pipe organ recordings, and I never felt the need to add subwoofers to my system.  These relatively compact acoustic suspension units can smoothly pump out the low frequencies, without distortion or boominess.  A shame that these types of speakers have almost disappeared from the market place today!