Whats a aperiodically-coupled bass-reflex box?
 

Good Evening everyone :D.

What is a aperiodically-coupled bass-reflex box? I was told it is a older design that dynaudio and kef used I think in the 70's. I tryed to google it but, I really didn't find anything or info in the web. Is there a box program that you can get that models this type of box? A friend of mine said it is a made up word and box design and there is no box modeling program that can make this type of box. So again any info in this type of box and why I have not seen or heard anyone talk about this type of box desgn or use it would be a big help. Thanks jm

An aperiodic box has a resistive vent. That could be a sealed box with a leak introduced, or a vented enclosure where the vent is stuffed (or has other resistance).

Yes I a friend of mine told me that some thing but, is there a picture or better insight why no one is using it these days and why?

Try googling "variovent" for one example, or simply "aperiodic vent". Resistance is built into many vents, e.g., high aspect ratio slot vents. Stuffing a vent is a popular tweak. It's never really gone out of style :)

You won't find a modeler that models these.

An aperiodic box can ve seen as a reflec with a resistor in the vent. Depending on the size of the R the box will range from BR (0) to sealed (infinity).

As to being used, i use these techniques all the time.

dave

Yes, I remember a number of variovent equipped Dynaudio designs in old Elektor magazines.

WinISD will "model" an aperiodic box if you lower the Ql parameter of a sealed design. Of course it's then hard to equate this to a real-life resistive vent unless you've done it a bunch of times and have a feel for it, so you still need to measure your impedance curve to get Fc and Qtc to know how close you are and adjust things. The range of useful Ql is usually between 1 and 2. Above this it won't do much and below it's getting a bit extreme.

I see two possible uses for doing this: being forced to put a driver in too small a box or preparing a driver in an OK size box to be driven by a high impedance.

High aspect reflex vents with a lot of wall surface area probably work differently from the above though.

IG

This is it(?): North Creek Music's new MAPD driver loading
On second read of the original post, This isn't it. It instantly popped into my head when I read the thread title and I was compelled to post it.

No thats not it but, thanks for the thought? jm

Okay then how can I make this kinda box for the fostex fe126en drivers just wondering? jm