I live in Calgary, and Mike in Red Deer is my closest DD dealer. (bought my 2512 from him). Go figure!

 

BTW, I don't get the whole "aperiodic membranes", Is this not just a fancy word for Acoustic Suspension??? or a dampening material behind a sub??? I'm confused??? Please enlighten me, so I can sell my customers "aperiodic membranes" too...I don't want to be "out of the loop", I live in a small town and it takes a while to catch on to the next big thing in the city???
Thanks,

 

If I recall correctly, they provide the same (tuneable) "resistance" using to the face of a sub which a proper enclosure would. That would allow you to mount 3-4 subs under your rear deck ot other such spots, almost in a free air config.
I remember reading about the founders (Eric & his brother, and their dad) who founded USD in CAR STEREO decades ago, putting only 2 15s, 2 12s and a pair of guides in their ride. (I may be confusing that car with Richard Clark's, unless he's their dad).
Anyway, COMPLETELY different ballgame than a flared end port

 

" aperiodic membranes"-I think that I am just going to call this style of enclosure or lack of "free air" or "acoustik suspension" or "let's just throw two subs in a board and see what happens"....We used to play alot with "free air", and with the right subs it was pretty good...very hard to tune, and was very sub specific.
It's good to see that I am not a total lost with the "aperiodic membranes"??? I had honestly never heard the term, we just called them something different...

 

BTW, at Mike's soundoff last year, we used the aeroport in our second run, and gained 3bd, just by flaring the port...amazing demo.

 

http://www.teamaudionutz.com/tutoria...iodic_Cookbook

3dB, huh? That's like turning your sedan into a hatchback! (Cabin gain)

 

You're quick,
We did not test before our first run, and then put the flare on one end of the port, and yes a disappointment of 135 turned into 138, which for our shop is disappointing most days. 1 12" sub, with 1 750watt amp (not bad), but at the end of the day, I would venture to say that the flare added 1-2db for sure, there are alway "tricks" to get louder, and we did incorporate some of the tricks in both runs....sooooo....who really knows????

 

Richard Clark bought the famous USD Grand National from Speaker Works. He claims to have done a lot of reworking of it but Eric Holdaway disagrees. It'd be sweet if this car went back on the circuit.

The most simple way to explain an AP setup is 'controlled free air'. At low frequencies the sound waves have enough energy to pass through the membrane like it isn't there, so you have the benefits of a large sealed box (trunk size). As the frequencies move up they have a harder time making it through the membrane so the cone's motion is controlled, like in a smaller sealed box. Back in the day when these were popular, your average 12 wanted about 3cuft to be happy and a 15 about 5cuft so they made sense. Now, not so much.

Typical results were deeeeeeeeeep bottom end and a reasonably controlled upper bass while sacrificing some sensitivity, ie not so loud without a shitton of power.

 

a more linear and controlled impedence response is another benefit especially when it comes to damping factor in an ap config

 

I seem to recall DC audio hitting in the 160's with 2 18's?(mayabe 15's), in an astro van last year....I get the concept, and it was great to see. although did not make it through the day with the subs, I recall the coils frying...which if the theory is correct, more power less control, bigger numbers???