Why not acoustic suspension?

I listen to AR9's that are 45 years old. They, to me, are the perfect example of the old acoustic suspension system. They were a reference speaker of their day. Many things have come and gone in the last 45 years. I still enjoy listening to my AR9's, nearly every day. They have the bast bass that I've ever owned, maybe the best that I've ever heard. They are no slouch in mid or highs either. They are a very well designed speaker system. I would never get rid of them. I might try something new at some point but if I don't, I'm OK with what I have as well. 

The AR9 was real acoustic suspension but a hanger on. By that time bass reflex had taken over. It became harder and harder to do acoustic suspension as bass reflex took over. Many(most?) speaker companies buy their drivers from a few main suppliers. And the suppliers build what sells. And bass reflex was what was selling. To get an acoustic suspension woofer you either had to design your own or pay a supplier to build something special for you which, of course, is more costly than standard designs.

And closed box is hard to sell now. It sounds different. Bass reflex sound is what most people have heard and what they think bass sounds like. There are very few closed box designs today. Off the top oif my head there's Magico, a top of the line design. But I don't know if they are acoustic suspension or closed box though I think they use the term acoustic suspension. They use closed box because they know it has less ringing that bass reflex.

@dynamiclinearity Wouldn't Legacy Focus SE be sealed enclosures? 

I may be too old school to "like" the new stuff. I really don't know. I get curious about the open baffle stuff, find it interesting but that's about as far as it goes for me. I have absolutely nowhere to listen to any new concepts or designs. I am very accustomed to what I do listen to and I don't ever get tired of it. I also have a pair of KEF R107's. They have a nice sound as well. 

I have to correct myself. I just looked at the Legacy Focus SE specs and it says that they are rear ported. 

Here ya go!

Acoustic suspension speakers are a specific type of sealed-box design that rely on a specially designed woofer and the air inside the cabinet for low-distortion, controlled bass, whereas general sealed-box speakers may not use this specialized driver design and may prioritize simplicity, compactness, and ease of construction.

Acoustic Suspension Speakers

Design Principle: Acoustic suspension speakers employ a woofer with very soft, compliant suspension components, and the air sealed inside the cabinet acts as a spring to return the cone to its rest position 

 

HUMAN Speakers+1

. This design provides a linear restoring force and reduces distortion, particularly at low frequencies 

 

Wikipedia+1

. The woofer’s mechanical suspension (spider and surround) primarily holds it in place without exerting most of the restoring force 

 

Audioholics

.

Performance Characteristics:

• Tighter, more controlled bass with a gentle roll-off (typically 12 dB/octave below resonance) 

   

  1

  .
• Lower distortion and better transient response compared to vented designs 

   

  2

  .
• Compact cabinet size with efficient bass performance, often delivering deep frequencies from a small enclosure 

   

  2

  .
• Precision and musical accuracy are prioritized over maximum output or absolute efficiency 

   

  1

  .

• 

  

  4 Sources

Applications: Ideal for hi-fi audio where accurate bass reproduction is more important than sheer bass extension or loudness. Often used in home stereo and critical listening setups 

 

HUMAN Speakers

.

General Sealed Box Speakers

Design Principle: A sealed box speaker, sometimes called a closed or sealed enclosure, does not have any ports or vents and relies on the air inside the box to provide some damping to the woofer 

 

All for Turntables

. Unlike dedicated acoustic suspension designs, it may use standard driver suspensions and does not necessarily optimize low-distortion bass behavior.

Performance Characteristics:

• Controlled bass with a smooth, gradual roll-off below the driver’s resonant frequency 

   

  1

  .
• Simpler and easier to build than an acoustic suspension system 

   

  1

  .
• Generally less sensitive and less efficient in producing very deep bass compared to acoustic suspension speakers of equal size 

   

  1

  .
• Still provides tight bass and works well in small spaces but may require more amplifier power to achieve the same output 

   

  2

  .

• 

  

  4 Sources

Applications: Commonly used in a variety of home and professional speakers, subwoofers, and bookshelf systems where simplicity, cost, and compactness are desired. These speakers may not attain the extremely low distortion levels of a true acoustic suspension speaker 

 

All for Turntables+1

.

Key Differences

Feature	Acoustic Suspension	Standard Sealed Box
Woofer design	Specialized compliant driver	Standard driver
Restoring force	Air spring in the cabinet	Combination of cone suspension and air
Bass roll-off	Gentle, 12 dB/octave	Gradual, may vary depending on driver
Distortion	Very low, well-controlled	Moderate; can vary
Cabinet size	Compact yet deep bass	Compact, sometimes less bass efficiency
Efficiency	Requires more power for same SPL	Slightly easier to drive
Application focus	Audiophile accuracy and transient response	Consumer or general-purpose use

In summary, all acoustic suspension speakers are sealed box designs, but not all sealed or closed boxes are true acoustic suspension systems. The former emphasizes specialized drivers and precise air-spring control to achieve high-fidelity, low-distortion bass, while the latter prioritizes simplicity and ease of integration into a room 

 

Audioholics+3

.