Do You Miss Acoustic Suspension Speakers?

[fmw]

If I remember the literature from Advent back in the day, the idea was to use more compliant, longer throw drivers that would gain some control from the air pressure inside the enclosure. The longer throw would produce better bass response than a normal driver but not sound loosy goosy. My subwoofer has a very long throw driver that goes down to the low 20's in a sealed enclosure. I think it is the same idea except that the subs aren't trying to reduce the size of the enclosures while the acoustic suspension speakers were all about that.

 

[Kingnoob]

If I remember the literature from Advent back in the day, the idea was to use more compliant, longer throw drivers that would gain some control from the air pressure inside the enclosure. The longer throw would produce better bass response than a normal driver but not sound loosy goosy. My subwoofer has a very long throw driver that goes down to the low 20's in a sealed enclosure. I think it is the same idea except that the subs aren't trying to reduce the size of the enclosures while the acoustic suspension speakers were all about that.

Even cheap subs claim to be long throw , but high end ones that are big Xmax are far superior just cost significantly more . Only some pro subs cannot claim big Xmax ?

Acoustic suspension requires a certain amount of internal volume ?

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[dlaloum]

The issue isn't so much "long throw" as the ultra light suspension used in the original AS woofer designs...

The surround was designed to impose as little resistance to motion as possible... support was from the sealed nature of the box.

More recent woofers seem to be mechanically quite different, and their "heavier" surround, is then dependent on and requires more work to drive it, and the surround keeps it in place - hence is inherently providing more resistance as well.

Are there manufacturers making woofers specifically designed for old style AS use?

 

[shadyJ]

Are there manufacturers making woofers specifically designed for old style AS use?

Nope. Modern loudspeaker drivers have much more powerful motors, and the magnetic field is a much larger factor in the restoring force of the coil position than backspring pressure from the air.

 

[dlaloum]

Nope. Modern loudspeaker drivers have much more powerful motors, and the magnetic field is a much larger factor in the restoring force of the coil position than backspring pressure from the air.

Which also means, as a direct corollary, that more power is required to drive the woofer... (and possibly also, higher distortion levels when driven at lower SPL's?)

 

[ryanosaur]

(and possibly also, higher distortion levels when driven at lower SPL's?)

I wouldn't necessarily expect that. If the Driver is well designed, it should perform well within it's first bit of stroke. On the other hand, it is in pushing that stroke toward Xmax where one would begin to expect issues in compression or other distortions.

 

[Verdinut]

Nope. Modern loudspeaker drivers have much more powerful motors, and the magnetic field is a much larger factor in the restoring force of the coil position than backspring pressure from the air.

James,
Also, I think you will agree with me with the fact that compliance of the suspension of the currently produced drivers is quite stiffer than that used on AS woofers. That also contributes to making them less dependent on enclosure backspring pressure.

 

[MrBoat]

No. When I was a lad during the roomie years, there were Advents and JBL L100s in the house simultaneously. For the kind of music I listened to, and the concerts I witnessed, the JBL just trounced the Advents. I never really looked back and ported, higher displacement designs were more of a sure bet. The Advents didn't sound bad, but more like they were just in the wrong neighborhood, perhaps.

The JBLs got flogged hard for about 3 years before they moved on with their actual owner and he still has them in play. As I get older and less complicated, a good, full-range, ported design, manages to spin my little flywheel most days.

My current F-12 Tempests manage to cure the JBL itch, and bring modern neutrality/imaging etc. as a fusion of sorts. Still, after more than 4 decades in, the three essential requirements with full-range speakers remains constant, and everything else can be reasoned out with headroom and (at least tone controls) EQ.

 

[shadyJ]

James,
Also, I think you will agree with me with the fact that compliance of the suspension of the currently produced drivers is quite stiffer than that used on AS woofers. That also contributes to making them less dependent on enclosure backspring pressure.

It's not just the compliance, it is the linear range of travel of the suspension. Modern driver suspension can have a ton of computer modeling to extract every last mm of Xmax. Some spiders use different materials going from the outer to inner radius. There are all kinds of different surround designs too. They all work with the motor to get a level of linear travel that far surpasses anything that was possible in AS's day. I am not sure the principles of acoustic suspension could be updated using modern design methods where it could be competitive against regular loudspeaker designs.

 

[Verdinut]

It's not just the compliance, it is the linear range of travel of the suspension. Modern driver suspension can have a ton of computer modeling to extract every last mm of Xmax. Some spiders use different materials going from the outer to inner radius. There are all kinds of different surround designs too. They all work with the motor to get a level of linear travel that far surpasses anything that was possible in AS's day. I am not sure the principles of acoustic suspension could be updated using modern design methods where it could be competitive against regular loudspeaker designs.

No matter the type of suspension used In any sealed enclosure, there will always be some linearity distortion caused by compression and decompression of the entrapped air. That is why a well designed woofer or subwoofer in a vented cabinet will distort less while being more efficient than the driver in a sealed box.

 

[fmw]

Even cheap subs claim to be long throw , but high end ones that are big Xmax are far superior just cost significantly more . Only some pro subs cannot claim big Xmax ?

Acoustic suspension requires a certain amount of internal volume ?

Sent from my iPhone using

I have no experience with pro subs so I can't comment. The 15" driver in my home theater sub has a huge convex rubber surround that lets the driver move a lot of air. I have three other subs in the house and none of them have the kind of surround of the 15 incher in my home theater. They do a decent job but seem to struggle compared to the 15 incher. But they are smaller 10 and 12" subs so it isn't a fair comparison.

 

[Kingnoob]

I have no experience with pro subs so I can't comment. The 15" driver in my home theater sub has a huge convex rubber surround that lets the driver move a lot of air. I have three other subs in the house and none of them have the kind of surround of the 15 incher in my home theater. They do a decent job but seem to struggle compared to the 15 incher. But they are smaller 10 and 12" subs so it isn't a fair comparison.

Yeah I have a similar sub in my set up I rarely use , and now the tv died in that set up . Unfortunately my 15” won’t fit in the room my main set up is in. So i stacked two 10” subs.
The 15” can easily rattle my bedroom. Sure looks dirty in the pics yet it’s not that’s the clear coat messed up everything.
Any pics of your sub or brand etc ? Mines stereo integrity 15”.