On Sat, 7 Apr 2012 08:50:33 +0100, "TonyL"
wrote:

Don Pearce wrote:


If they are foam or a
rubber roll, give them a go. You won't go far wrong with a large box,
although you might get better results from measuring the Thiele-Small
parameters and designing a proper box.

Rubber.


How involved do you want to get?


It is just a vague idea right now. They were bought as replacement drivers
for a very old pair of Wharfedale speakers a couple of years back and they
were fine. But then I found some replacement surrounds for the Wharfedale
units and restored them.

Would knowing T/S parameters help much in the case of a sealed enclosure?

My initial idea was just a big rigid box, stuffed with wadding. Box volume
being constrained by the fact that I want to stay married.

For a sealed box, no you don't need to know the T/S parameters. The
question is really one of diminishing returns as you make the box
bigger. This is determined by the stiffness of the speaker suspension
which is specified in T/S as an equivalent box size (smaller box =
stiffer suspension). There is no point making the box much bigger than
this, as the suspension stiffness will take over control.

The advantage of doing the measurements and making a ported box is
that it makes use of the speaker's resonance, coupled to the box/port
resonance to prop up the natural low frequency roll-off for a while,
extending the bass response. The cost is that once roll-off inevitably
sets in, it is much steeper, and the residue of the resonances can
make the bass a bit flabby unless it is all configured just right.
That can always be a future project, of course.

d