Slightly off the wall, but bear with me...

Whatever subs I end up with, there will come a time when the large 3-way
boxes I'm using at present will no longer contain bass drivers and will be
replaced. The replacement cabs will likely use the existing KEF B110 and T27
drivers.

I'd like the small cabs to be as free of possible resonances and similar
effects as is feasible. To this end, those Nautilus snail shell thingies
have interesting enclosures for the mid-range drivers - very non-box-shaped,
and there's no baffle board.

Assuming I'm able to fabricate an enclosure of this type, would the general
principle of a cylindrical cab with a rounded interior shape and no baffle
work well with my drivers? If so, what materials might be suitable? I
envisage a volume of around 8 litres, rough outer dimensions being 150mm
diameter and 300mm or so long. So far, I've considered the following
construction approaches...

Cut a series of rings out of MDF, glue them together to create a tapered
cylinder, then work them to get a smooth surface.

Mould the cabinets out of GRP. Could there be resonances with this approach?
If thickness will reduce them, how thick would be good enough? 10-12mm?

Make them out of some sort of resinous paste, perhaps using wire
reinforcement for the main structure and metal plates for fitting points.
How about car body filler for this approach? If not, what other paste-type
materials are worth looking at?


--
Wally
www.art-gallery.myby.co.uk
Moving soon to: www.artbywally.com

On Tue, 13 Jan 2004 15:16:59 -0000, "Wally"
wrote:

Slightly off the wall, but bear with me...

Whatever subs I end up with, there will come a time when the large 3-way
boxes I'm using at present will no longer contain bass drivers and will be
replaced. The replacement cabs will likely use the existing KEF B110 and T27
drivers.

I'd like the small cabs to be as free of possible resonances and similar
effects as is feasible. To this end, those Nautilus snail shell thingies
have interesting enclosures for the mid-range drivers - very non-box-shaped,
and there's no baffle board.

Assuming I'm able to fabricate an enclosure of this type, would the general
principle of a cylindrical cab with a rounded interior shape and no baffle
work well with my drivers? If so, what materials might be suitable? I
envisage a volume of around 8 litres, rough outer dimensions being 150mm
diameter and 300mm or so long. So far, I've considered the following
construction approaches...

Cut a series of rings out of MDF, glue them together to create a tapered
cylinder, then work them to get a smooth surface.

Mould the cabinets out of GRP. Could there be resonances with this approach?
If thickness will reduce them, how thick would be good enough? 10-12mm?

Make them out of some sort of resinous paste, perhaps using wire
reinforcement for the main structure and metal plates for fitting points.
How about car body filler for this approach? If not, what other paste-type
materials are worth looking at?

There was a design recommended by Wharfedale back in the sixties that
used a concrete drain pipe for exactly the purpose you describe. I'm
sure that with a little searching round the bigger plumbers you could
find something suitable.

d

_____________________________

http://www.pearce.uk.com

On Tue, 13 Jan 2004 15:16:59 -0000, "Wally"
wrote:

Slightly off the wall, but bear with me...

Whatever subs I end up with, there will come a time when the large 3-way
boxes I'm using at present will no longer contain bass drivers and will be
replaced. The replacement cabs will likely use the existing KEF B110 and T27
drivers.

I'd like the small cabs to be as free of possible resonances and similar
effects as is feasible. To this end, those Nautilus snail shell thingies
have interesting enclosures for the mid-range drivers - very non-box-shaped,
and there's no baffle board.

Assuming I'm able to fabricate an enclosure of this type, would the general
principle of a cylindrical cab with a rounded interior shape and no baffle
work well with my drivers? If so, what materials might be suitable? I
envisage a volume of around 8 litres, rough outer dimensions being 150mm
diameter and 300mm or so long. So far, I've considered the following
construction approaches...

Cut a series of rings out of MDF, glue them together to create a tapered
cylinder, then work them to get a smooth surface.

Mould the cabinets out of GRP. Could there be resonances with this approach?
If thickness will reduce them, how thick would be good enough? 10-12mm?

Make them out of some sort of resinous paste, perhaps using wire
reinforcement for the main structure and metal plates for fitting points.
How about car body filler for this approach? If not, what other paste-type
materials are worth looking at?

There was a design recommended by Wharfedale back in the sixties that
used a concrete drain pipe for exactly the purpose you describe. I'm
sure that with a little searching round the bigger plumbers you could
find something suitable.

d

_____________________________

http://www.pearce.uk.com

On Tue, 13 Jan 2004 15:16:59 -0000, Wally wrote:

This might interest:
http://www.lungster.com/l/speakers/sonotubefaq.html

--
Jim H jh
@333
.org

On Tue, 13 Jan 2004 15:16:59 -0000, Wally wrote:

This might interest:
http://www.lungster.com/l/speakers/sonotubefaq.html

--
Jim H jh
@333
.org

Don Pearce wrote:

There was a design recommended by Wharfedale back in the sixties that
used a concrete drain pipe for exactly the purpose you describe. I'm
sure that with a little searching round the bigger plumbers you could
find something suitable.

I remember something like that (with the driver mounted in the side rather
than on the end). I'll be having a wander round the local DIY to check out
their audiophile-quality garden ornaments...


--
Wally
www.art-gallery.myby.co.uk
Moving soon to: www.artbywally.com

Don Pearce wrote:

There was a design recommended by Wharfedale back in the sixties that
used a concrete drain pipe for exactly the purpose you describe. I'm
sure that with a little searching round the bigger plumbers you could
find something suitable.

I remember something like that (with the driver mounted in the side rather
than on the end). I'll be having a wander round the local DIY to check out
their audiophile-quality garden ornaments...


--
Wally
www.art-gallery.myby.co.uk
Moving soon to: www.artbywally.com

Jim H wrote:

This might interest:
http://www.lungster.com/l/speakers/sonotubefaq.html

Indeed - cheers.


--
Wally
www.art-gallery.myby.co.uk
Moving soon to: www.artbywally.com

Jim H wrote:

This might interest:
http://www.lungster.com/l/speakers/sonotubefaq.html

Indeed - cheers.


--
Wally
www.art-gallery.myby.co.uk
Moving soon to: www.artbywally.com

I have a pair of 45 degree pipe enclosures - heavy ceramic. Interior diameter
is 12". Yours free - come and collect, Kensington London. 020-7602-2707

I had absolutely great results with some heavy concrete 45 degree angles I used
in Norway. They were presumably sewerage pipes that were extra robust to endure
freezing. One of the cleanest sounds I ever had. Totally inert and no standing
waves.


=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.