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?

Please note that the Nautili do *not* use a cylindrical midrange
enclosure, it's diffraction characteristics are much closer to those
of a sphere. See the classic Olsen plots from the '50s to see the
difference this makes.

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?

KEF used commercial fishing floats for the 'Eureka' project in the
'70s. Alternatively, why not use concrete? It's easily moulded onto a
chicken wire armature, and very rigid.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Stewart Pinkerton wrote:

Please note that the Nautili do *not* use a cylindrical midrange
enclosure,

Well, I was envisaging a tapered pipe, perhaps with a domed interior end
opposite the driver. Not a plain cylinder, IOW.


... it's diffraction characteristics are much closer to those
of a sphere. See the classic Olsen plots from the '50s to see the
difference this makes.

I'll googlify on that...


KEF used commercial fishing floats for the 'Eureka' project in the
'70s.

Interesting.


Alternatively, why not use concrete? It's easily moulded onto a
chicken wire armature, and very rigid.

Could do. I was thinking of car body filler because it can take a very
smooth finish - I guess it could be used as a final layer on concrete.


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

Stewart Pinkerton wrote:

Please note that the Nautili do *not* use a cylindrical midrange
enclosure,

Well, I was envisaging a tapered pipe, perhaps with a domed interior end
opposite the driver. Not a plain cylinder, IOW.


... it's diffraction characteristics are much closer to those
of a sphere. See the classic Olsen plots from the '50s to see the
difference this makes.

I'll googlify on that...


KEF used commercial fishing floats for the 'Eureka' project in the
'70s.

Interesting.


Alternatively, why not use concrete? It's easily moulded onto a
chicken wire armature, and very rigid.

Could do. I was thinking of car body filler because it can take a very
smooth finish - I guess it could be used as a final layer on concrete.


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

On Tue, 13 Jan 2004 18:00:55 +0000 (UTC),
(Stewart Pinkerton) wrote:

On Tue, 13 Jan 2004 16:05:08 -0000, "Wally"
wrote:

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...

The Wharfedale design used the driver mounted vertically in the end of
the pipe, with a conical reflector suspended above it.

And didn't it use the Super 8 RSDD driver that got discussed to death
here recently?

d

_____________________________

http://www.pearce.uk.com

On Tue, 13 Jan 2004 18:00:55 +0000 (UTC),
(Stewart Pinkerton) wrote:

On Tue, 13 Jan 2004 16:05:08 -0000, "Wally"
wrote:

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...

The Wharfedale design used the driver mounted vertically in the end of
the pipe, with a conical reflector suspended above it.

And didn't it use the Super 8 RSDD driver that got discussed to death
here recently?

d

_____________________________

http://www.pearce.uk.com

Stewart Pinkerton wrote:

The Wharfedale design used the driver mounted vertically in the end of
the pipe, with a conical reflector suspended above it.

Maybe it wasn't the Wharfdale that I saw (a picture of). I do remember a
drainpipe jobbie with the driver in the side. Rogers, maybe?


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

Stewart Pinkerton wrote:

The Wharfedale design used the driver mounted vertically in the end of
the pipe, with a conical reflector suspended above it.

Maybe it wasn't the Wharfdale that I saw (a picture of). I do remember a
drainpipe jobbie with the driver in the side. Rogers, maybe?


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

Jim H wrote:

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

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

The only place I found in the UK that makes tubes like
Sonotube(tm) is Essex Tube Windings in Tilbury.
http://www.essextubes.com
The don't seem to have any distributors but will make
any size you want. They take credit cards and will deliver,
presumably in a protective cardboard tube.

A 12" woofer at one end of a 10' pipe behind the settee would
make an interesting TL sub.

--
Roger.

Jim H wrote:

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

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

The only place I found in the UK that makes tubes like
Sonotube(tm) is Essex Tube Windings in Tilbury.
http://www.essextubes.com
The don't seem to have any distributors but will make
any size you want. They take credit cards and will deliver,
presumably in a protective cardboard tube.

A 12" woofer at one end of a 10' pipe behind the settee would
make an interesting TL sub.

--
Roger.

Old Fart at Play wrote:

The only place I found in the UK that makes tubes like
Sonotube(tm) is Essex Tube Windings in Tilbury.
http://www.essextubes.com
The don't seem to have any distributors but will make
any size you want. They take credit cards and will deliver,
presumably in a protective cardboard tube.

Cheers - I'll have a shoofty.


A 12" woofer at one end of a 10' pipe behind the settee would
make an interesting TL sub.

eyes gap behind sofa...


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