Which Tannoys, folks?

[Reffc]

CAD mock up's completed. First one shows the bare cab cut for driver and ports:




There'll be some sneaky design such as burying small neodymium magnets set into the ply front baffle underneath the veneer, with corresponting magnetic strips set into the grill beneath the cloth so that the front lines of he woodwork will remain unspoilt with the covers removed. With the full length cover on, the cabinet will look like this:



Not unlike my older Horning Agathon Ultimates in front profile except larger! A shade under 1.3m tall but with rounded side panels.

[montesquieu]

Not unlike my older Horning Agathon Ultimates in front profile except larger! A shade under 1.3m tall but with rounded side panels.

Looks gorgeous Paul.

Does it come in 15in?

[Reffc]

Looks gorgeous Paul.

Does it come in 15in?

It can certainly be arranged Tom. A 15 inch driver would add 50mm all round on the dimensions (gross volume of 230 litres). No shrinking violets!

[montesquieu]

It can certainly be arranged Tom. A 15 inch driver would add 50mm all round on the dimensions (gross volume of 230 litres). No shrinking violets!

Tannoy seem to have gone to long slotted ports rather than the round tube approach which in some setups can be a bit 'obvious' (chuffing and wheezing). Any rationale for going either way? Is there method in calculating the opening size and placement?

[Reffc]

Tannoy seem to have gone to long slotted ports rather than the round tube approach which in some setups can be a bit 'obvious' (chuffing and wheezing). Any rationale for going either way? Is there method in calculating the opening size and placement?

The reason they've done that I think is largely cosmetic Tom, but I did find hat the crudely cut port (no shaped entrance etc) being narrow was a little wheezy and could make the bass a little slow sounding.

I've used a standard Helmholtz model to check the ports and have gone with an arrangement similar to that recommended by Alex Garner of Tannoy: Two 100 diameter ports 200mm long. I've placed these fairly high in the cab as that helps with bass speed (apparently) although I'm unsure of how it affects the mid-point standing wave (or vice-versa)which tries to form in tall cabs (max amplitude at the mid point) but have designed a lot of wadding around a central chamber at this point to negate that effect. I've also used WinISD to check and that model came out with a similar result (suggesting 3mm longer ports, but what is 3mm between friends?)

[walpurgis]

Your cabs look rather long. Will they be baffled to break up standing waves along the major dimension?

[Reffc]

Your cabs look rather long. Will they be baffled to break up standing waves along the major dimension?

The length isn't an issue on its own, as the formation and control of standing waves is a little more complex than just analysing the length. The internal length is 1.16m, reduced to an effective length of 1.13m due to internal acoustically non-transparent damping and wadding. In the middle, there will be additional wadding to help damp down the amplitude of any waves forming along the length although there will be holes or gaps to allow the lower ports to be driven properly. The internal dimensions have all been selected so that there are no equal multiples with respect to each other (this is very important) and the side panels curved to reduce internal reflections in that plane. There are also internal ribs which protrude 50mm into the cabinet asymmetrically spaced and these have internal cross bracing which also helps break up standing waves. In theory, they should be very well damped and controlled in this respect.

[Reffc]

Veneer's here...all 10 sheets!





Bellmouth ports

[Reffc]

Slow progress, as too many other things to do! Still, managed to get all materials now and totalling up the cost needed some smelling salts and sweet tea to bring me round!

Covered the ports in the same 12mm dense wool felt that will be applied to the inside of the speakers:



I've also modified the front baffle board design in an attempt to bring down the resonant frequency of the panel, and introduced an extra coupling brace. The baffle is now 25mm Birch ply with an inside panel of 6mm MDF glued to it and 2mm Bitumen sheeting applied to the MDF internal face plus 12mm dense wool felt. I'm taking no prisoners. These panels will be as acoustically dead as I can get them!

[Macca]

Hi Paul

Have you considered Deflex Panels rather than all that wadding - I had good results with them years ago - they kill the box reverb without deadening the sound.

http://www.madisoundspeakerstore.com...tandard-panel/