low-mass aka cat in pidgeons
Not CLD, but another local who used to teach speakers in college, makes drivers, ESLs, dipoles etc, last night suggested
“These are the L/R speakers for the Plasma surround system, used above 50 Hz.
Front is 18 mm chipboard.
Top, bottom & sides are two layers of 3 mm MDF (3 mm is not a typo).
Back is single layer 3 mm MDF.
Raw box weight is about 2.5 kg. Inside is lined all over with 2 layers of "Bostic Sheetform", which took it up to about 6 kg.
The rebuilt Jordan-Watts (weighing 4 kg, and used up to 600 Hz) is decoupled from the box with thick felt gaskets.
Very little panel movement on music, and boxy coloration is nearly as low as the open-baffles in my main stereo system (these, of course, have none).
If I ever need box speakers, I will do this again, except I would interleave the 4 layers”
. .
Not CLD, but another local who used to teach speakers in college, makes drivers, ESLs, dipoles etc, last night suggested
“These are the L/R speakers for the Plasma surround system, used above 50 Hz.
Front is 18 mm chipboard.
Top, bottom & sides are two layers of 3 mm MDF (3 mm is not a typo).
Back is single layer 3 mm MDF.
Raw box weight is about 2.5 kg. Inside is lined all over with 2 layers of "Bostic Sheetform", which took it up to about 6 kg.
The rebuilt Jordan-Watts (weighing 4 kg, and used up to 600 Hz) is decoupled from the box with thick felt gaskets.
Very little panel movement on music, and boxy coloration is nearly as low as the open-baffles in my main stereo system (these, of course, have none).
If I ever need box speakers, I will do this again, except I would interleave the 4 layers”
. .
While Linkwitz
. . found that in his 5th page here
www.linkwitzlab.com/sb80-3wy.htm that 6 mm ply with 15 mm of damping (he did some home made) worked well.
From the original mahogany board(?), but it cut decay time by 75% time – I think due to the low mass.
(And lowered the resonance by a third of an octave)
Rick
. . found that in his 5th page here
www.linkwitzlab.com/sb80-3wy.htm that 6 mm ply with 15 mm of damping (he did some home made) worked well.
From the original mahogany board(?), but it cut decay time by 75% time – I think due to the low mass.
(And lowered the resonance by a third of an octave)
Rick
Dave
Some interesting ideas. (I’ll do an open baffle when space and time permit) . .
I’m hoping to avoid going nuts
(with sone other readin as well) I see the benefits of aperiodic. I wonder why they’re uncommon among commercial designs currently available?
the Fonken is a verry interesting combination, what would be the best choice for panels: birch ply, say 12 mm?
“Coupling as much of the driver to as much of the box as possible helps” -
doesn’t that maximise the transmission of driver vibration to the box?
Cheers
Some interesting ideas. (I’ll do an open baffle when space and time permit) . .
I’m hoping to avoid going nuts
(with sone other readin as well) I see the benefits of aperiodic. I wonder why they’re uncommon among commercial designs currently available?
the Fonken is a verry interesting combination, what would be the best choice for panels: birch ply, say 12 mm?
“Coupling as much of the driver to as much of the box as possible helps” -
doesn’t that maximise the transmission of driver vibration to the box?
Cheers
rick57 said:
They are hard to market, and no-one has accurate tools to model them... World design has an aperiodic kit, loosely base on the Dynaco A25 (same designer). The A25 could well be the speaker that holds the record for most units sold -- it was aperiodic.
that is as designed (uses a 18mm baffle). I am re-jigging for 15mm material for economy of material.
Exactly... instead of the baffle getting all the energy, we are spreading it over the entire box. A lower energy density means you are less likely to excit panel resonances.
dave
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