In message , Wally
writes
Chris Morriss wrote:

I've got 'WinSpeakerz' on the pc, so if you let me know the box
volume I could give you a reasonable idea of the LF response.

I'm looking at doing a Nautilus-style tubular enclosure. Some pictures...

http://www.wally.myby.co.uk/audio/sp...ExpoCab-01.jpg
http://www.wally.myby.co.uk/audio/sp...ExpoCab-02.jpg
http://www.wally.myby.co.uk/audio/sp...ExpoCab-03.jpg


If the prog can do such a shape, the dims are, in mm...

length - 400
dia large - 180
dia small - 40

The volume of the cab as drawn is 2.85 litres, which is too small for
extending the bass - KEF say 4L for a midrange box, 5-10 for bass/mid. So,
I'm wondering what could be acheived by keeping the narrow end of the pipe
open, like a sort of transmission line with some damping due to the rear
opening having a small area.


--
Wally
www.artbywally.com
www.wally.myby.co.uk/music



A 'nautilus shell' style enclosure is a difficult beast to analyse, and
it's out of my depth! (a closed, tapered transmission line).

You're right about the enclosure volume being a bit low for the B110 if
it was a simple sealed box, but still OK for a filter -3dB of 500Hz or
so.

For a simple sealed box of 2.85 litre with the B110, the Qtc is 0.944,
the -3dB point is 94Hz, and there is a broad resonant peak of approx
+1dB centred at 160Hz. (There are a number of flavours of B110. I don't
know how much the parameters vary)

With the right crossover this volume would still be OK as a housing for
the B100 if it was appropriately filtered as a midrange unit. (For
400/500Hz and above)

Perhaps others can help with the analysis of a closed or open ended
tapered TL?

--
Chris Morriss