What parameters to watch for in a basketless PR

[goldyrathore]

I am trying to understand a basketless PR like this one Audio Innovation - by Dan Marx www.danmarx.org

How does the characteristic of surround affect the parameters of the PR. After all there are plenty of choices to make with surround type, foam vs rubber, stiff vs loose ones etc.
What are the design goals in such a PR?

Can someone help me understand.

Thanks,
Goldy

[GM]

Same as for any other direct radiator AFAIK, the higher the suspension's compliance a proportionately less mass required for a given Fs and vice versa and of course a very rigid diaphragm for max radiation efficiency.

GM

[Andrew Eckhardt]

Looks like bull to me. It's still going to rock a Lot compared to using a spider. The critical thing for supressing this isn't the type of suspension used but the distance between a pair, which this innovator seems to be unfortunately trying to minimize.

[GM]

Yeah, me and a couple of others on the old 'FR' forum thought so too back when he first published it, but we tried it using the ultra cheap corrugated cardboard diaphragm units and in tiny cabs with 4"- 5.25" 'FR' drivers that required relatively large, long vents it worked fine, but no way would we consider it for a high excursion app.

GM

[18Hurts]

SLAPS Passive Radiator

Earthquake has been making that type for a few years.

[moray james]

A good friend has a pair of ESS Heil AMT 1D and the ten inch rear passive has only one suspension. These speakers make lots of very deep clean sounding bass so it can work well. Dual suspension will obviously be requires for high levels of travel if you want to keep things stable. I would guess the woofer (in the AMT) has a linear travel of 2.5 mm tops and an X-max of perhaps double that. Oskar knew what he was doing. Best regards Moray James.

[moray james]

I would like to make a correction. The speakers my friend has are AMT2's they have 1D crossover boards with some parts left off. So these are a ten inch front mounted pressed steel basket woofer and a ten inch rear mounted passive with only one suspension. And while they sound very authoritative I would guess 40 Hz maybe a little lower but they are convincing all the same. Nice speaker. Thanks. Best regards Moray James.