Zaphs B3S's with aperiodic membrane?

[GuyPanico]

In an attempt to make the B3S's even smaller, could one use an aperiodic membrane? Then decrease the cabinet volume maybe 2/3 or 3/4. I would of course have to play with the baffle step. But my ears are not tuned terribly well, so I dont need perfection. Any thoughts would be appreciated.

 

[planet10]

Surely worth a try... we are just embarking on a similar project with the CSS FR125S -- we'll see how they work stuffed into a 4 litre enclosure.

dave

 

[owdi]

AFAIK, in order for an AP to be effective it needs to vent into a volume separate from the driver, because it's out of phase. If you want really small why not try dipole?

Dan

 

[planet10]

AFAIK, in order for an AP to be effective it needs to vent into a volume separate from the driver, because it's out of phase.

That's news to me. Most aperiodic boxes vent to the outside. the Dynaco A25 being the most famous.

dave

 

[noodle_snacks]

AFAIK, in order for an AP to be effective it needs to vent into a volume separate from the driver, because it's out of phase. If you want really small why not try dipole?

Dan

I'd also question the logic in going dipole with this driver, i think the excursion limits, by the time you'd equalised everything would severely limit output.

I thought aperiodic vents basically acted as an acoustic resistor between the inside and outside of the box, simulating the effects of a larger box (air inside the box becomes more compliant), at the cost of a higher f3 and a steeper 18db/oct roll off.

 

[planet10]

[I thought aperiodic vents basically acted as an acoustic resistor between the inside and outside of the box, simulating the effects of a larger box (air inside the box becomes more compliant), at the cost of a higher f3 and a steeper 18db/oct roll off.

pretty much....

http://p10hifi.net/tlinespeakers/TLS/downloads/TedJordanAperiodic.pdf

dave

 

[sreten]

Hi,

The Vas of of the B3S is 0.8L, the box volume 3.2L.

Box volume is not part of the design, its actually lazy re-use
of existing boxes which the article should make more clear.

Aperiodic loading is pointless as as stated they should be used
with an active crossover, sealed box loading down to 1L is fine.
Baffle step changes should not be an issue, with same baffle width.

For full range use the Aurasound driver is the 3" bass champion.

/sreten.

 

[planet10]

For full range use the Aurasound driver is the 3" bass champion.

I can't disagree with you there sreten

Pretty good eleswhere as well -- and if you want to guild the lily, it plays well with the Apexjr $1 tweeter.

dave

 

[soongsc]

pretty much....

http://homepage.mac.com/tlinespeakers/TLS/downloads/TedJordanAperiodic.pdf

dave

I think the Jordan Watts were designed with this in mind, however, once they were enclosed in very small boxes, the aperiodic design lost it's function.

 

[Jim McPherson]

Hi,

The Vas of of the B3S is 0.8L, the box volume 3.2L.

I've seen you quote this many times sreten. Were did you get this info?
According to:
Parts Express
And:
Solen
The VAS of the B3S is 1.6L or 0.06 cu. Ft. The box volume of 3.2L is double VAS, this doesn't seem "lazy" to me. It seems like a reasonable box size. Sure it could be smaller, but 1L is surely too small.

-Jim

 

[sreten]

I've seen you quote this many times sreten. Were did you get this info?
According to:
Parts Express
And:
Solen
The VAS of the B3S is 1.6L or 0.06 cu. Ft. The box volume of 3.2L is double VAS, this doesn't seem "lazy" to me. It seems like a reasonable box size. Sure it could be smaller, but 1L is surely too small.

-Jim

Hi,

An externally hosted image should be here but it was not working when we last tested it.

As measured by Zaph - which I'd rather believe.

1L is too small for 1.6L, but not for 0.8L.

/sreten.

 

[Jim McPherson]

Well that makes sense. Thanks, that's very interesting. I'll be able to put that too the test soon. I've built a 3.2L enclosure and a 1.6L enclosure for the B3S, I'll take some FR measurements and note the differences.

-Jim

 

[sreten]

Hi,

Qbox 1L = 1.34 (red), 1.6L = 1.22 (yellow), 3.2L = 1.12 (green).

Shown no stuffing. This peak interacts with with the active c/o setting.

/sreten.

 

[planet10]

As measured by Zaph - which I'd rather believe.

One thing that i have discovered is that they both could be right. Measured T/S parameters are quite sensitive to measurement conditions. One has to think of the T/S parameters as a series of interrelated curves with the predominant input variable the voltage drive.

This means that the nice little world we have built to use T/S parameters to design our boxes is rocked... how your driver will respond in your box is dependent on how loud you play it.

This has moved me even more in the direction i have been heading already... designing boxes that have a greater tendency to work well anywhere on the T/S curves. Aperiodic is one of those.

dave