High Efficiency Speaker Asylum Need speakers that can rock with just one watt? You found da place.

---

[ Follow Ups ] Thread: [ Display  All  Email ] [ High Efficiency Speaker Asylum ]

---

[ Alert Moderator ]

---

My TS / what if's OLD box-package is dead, soooo ...... ? help?

Posted by Timbo in Oz (A) on March 7, 2007 at 21:26:07

Briefly, I have the opportunity to try out some baffle Diffraction Step (BDS-Eq) and ELF(-ish)* experiments with a 2nd pair of matching spheres. They'll sit UNDER the main pair of spheres I now have. Like a stack of the older Gallos!?

* using, IF required a '6th order assisted' alignment. IE an Rb tuned to as low as 2/3rd Fs, PLUS a '2nd order with gain' active HP filter. After a 2nd order LP filter (@150hz plus) - adjusted by ear for BDS compensation.

Foster(x now) FW202 8 inch bass driver, 23litres true Vb, counting it and the port volume. Port was 6.6cm by 15.5cm, and back then the target Fb WAS 38hz, QB3. The only specs for this driver are here at

http://db.audioasylum.com/cgi/m.mpl?forum=hug&n=110031&highlight=FW202,+Foster&r=&session=

Can someone check those numbers please?

NB what I am asking for below is 'a base-line check' - that I won't be tuning the 'new Vb' unfeasibly low for the drivers.

So, the new column of spheres - aka the tower of ball-power ;-)! - will begin with each of this 2nd pair - facing downwards! -
- 15 inch/38cm flat baffle, and approx 24 inch o.D.

Onto - and into, for stability - a squat and dense cylinder of 5 layers of scrounged processed-board, all glue/pressed, in a 60cm/24" circle.

The resulting mounting will sit above the existing 60cm round white pavers on three ~8cm or less ~ legs. This should be dead enough, even with the cut out down its middle for IF I leave the bass driver IN the sphere.

But, it could also be used to add some volume to the enclosure, and also to add an extension to the length of the existing port. (Noting that this extension port would be inside the thickest part of the MDF 'wall'!).

It may be that the new Vb and new port length WILL give a kneed response, and require a bit of 2nd order active boost - IE a '6th order 'Rbox. I'll be filtering below the Fb point achieved anyway!

I have sufficient scrap/scrounged MDF plus some chipboard to have a slab whose available height - for adding extra volume - would be 9.8cms or a bit less.

The feasible cut-out's surface area? The sphere's existing port is going to be firing down into matching tunnel cut through the MDF layers, and MUST have good seals at ALL those glue joints!

So, the cut out can't be completely regular, whic is bugger for easy measurements! I ended up with - 'a 30cm circular central hole, but with a flat section one one side'! Like a slice |) cut off one side, widest depth being = 8 cm's. IE a 22cm x 30cm 'cylinder'.

Anyone here dare?

to estimate the NEW Vb? and

to help me figure out what the Fb might be, ball park!?

?

Though it 'has' a nice tight large area slot to fire into, beside its woofer, # B&W did this for the N801's slot-loaded (woofer and) port, eh?

YES I knew there COULD/should be a 'knee' - BEFORE the 4th order slope starts! WHEN a '2nd-order filter with gain' could be used to help out. BTA floor and room-gain may be sufficient anyway.
Warmest

Timbo in Oz
The Skyptical Mensurer and Audio Scrounger

And gladly would he learn and gladly teach - Chaucer. ;-)!

'Still not saluting.'

This post is made possible by the generous support of people like you and our sponsors:

Kimber Kable

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---