Dunlavy
Very interesting and helpful.
From your description, it sounds like some type of bedding foam.
Any other info on Dunlavy would be appreciated.
My diy speakers are modeled after the SCIV, but using 8’s instead of 10’s.
Thanks again.
Very interesting and helpful.
From your description, it sounds like some type of bedding foam.
Any other info on Dunlavy would be appreciated.
My diy speakers are modeled after the SCIV, but using 8’s instead of 10’s.
Thanks again.
Johnny k
Read your post about Dunlavy interior stuffing.
I searched for the Dunlop Hypersoft HS 1730, and as you stated, it is no longer produced.
I assume it was to absorb all interior sounds and reflections.
Any idea if Dunlavy used a suitable substitute?
Read your post about Dunlavy interior stuffing.
I searched for the Dunlop Hypersoft HS 1730, and as you stated, it is no longer produced.
I assume it was to absorb all interior sounds and reflections.
Any idea if Dunlavy used a suitable substitute?
Dunlavy used HS1730 exclusively as far as I know.
My IV, SC-1’s & SM-1’s all use it.
It has a different feel than many other foams I have used.
It is a Latex foam with a very consistent pore size when looked at under a microscope.
It definitely has a “memory foam” type feel to it....
My IV, SC-1’s & SM-1’s all use it.
It has a different feel than many other foams I have used.
It is a Latex foam with a very consistent pore size when looked at under a microscope.
It definitely has a “memory foam” type feel to it....
Thanks to johnnyk.
Contacted a firm in Australia called:Luxaform North.
You are right again!
They do not produce the foam that Dunlavy used any longer.
Suggested replacement is:”AA2240.
Now all I have to do is trace this.
Thanks again.
Contacted a firm in Australia called:Luxaform North.
You are right again!
They do not produce the foam that Dunlavy used any longer.
Suggested replacement is:”AA2240.
Now all I have to do is trace this.
Thanks again.
Well, just received a message from Luxfoam.....
I had asked about AA2240 as a replacement for HS1730 and this is what she responded with....
“Hi John,
Yes it is what we used to replace it.
Found that it wasn’t nearly as good though so no longer use it.
There may be other foam retailers such as Joyce or Premier that sell something more like it.
Kind regards,
Caroline
Luxafoam North
33 George St
Avalon NSW 2107
0414 468 434
I had asked about AA2240 as a replacement for HS1730 and this is what she responded with....
“Hi John,
Yes it is what we used to replace it.
Found that it wasn’t nearly as good though so no longer use it.
There may be other foam retailers such as Joyce or Premier that sell something more like it.
Kind regards,
Caroline
Luxafoam North
33 George St
Avalon NSW 2107
0414 468 434
Ill take a look at those other manufacturers of “Memory Foam”.
It seems to be an “elusive” product.
Thanks for posting.
It seems to be an “elusive” product.
Thanks for posting.
Another clue to Dunlavy’s designs as mentioned by JD is modeling speakers as “distributed line” antenna theory.
I think if you research “acoustic impedance” some clues can be found.
Reading some google patents about manipulating A.I. Can be done several methods.
Aperiodic, mesh on font or back of speaker, stuffing……
What is nuts to me is Dunlavy speakers such as ; Aletha, Athena, Corinthian, SC-IIIA
Is getting the bass extension claimed from a Scanspeak 25w8565 in a 2 ft3 enclosure.
He always claimed critically damped alignments which should be almost 6.0 ft3
I think if you research “acoustic impedance” some clues can be found.
Reading some google patents about manipulating A.I. Can be done several methods.
Aperiodic, mesh on font or back of speaker, stuffing……
What is nuts to me is Dunlavy speakers such as ; Aletha, Athena, Corinthian, SC-IIIA
Is getting the bass extension claimed from a Scanspeak 25w8565 in a 2 ft3 enclosure.
He always claimed critically damped alignments which should be almost 6.0 ft3
Great info for more research.
Did a search of Dunlavy’s antenna designs.
Acoustic impedance too.
He was a smart guy!
Thanks for posting.
Did a search of Dunlavy’s antenna designs.
Acoustic impedance too.
He was a smart guy!
Thanks for posting.
I'm not sure if this is the right thread for this, but here goes. I am currently building a subwoofer with previously owned drivers. The vintage Scanspeak 10" will be in a bipolar slightly oversized box. I wish to protect them, since I will be using an also previously owned oversized power amp. These have a resonant frequency of 29hz, plenty deep enough for my apartment.
Is it feasible to just make a second order passive filter at the resonant peak, using that peak for impedence calculations?
Not sure if the nominal paralleled 4 ohm rating would work.
I do have an active 4th order fixed line level crossover available that has a built in 2nd order highpass at 32 hertz, but would prefer to only use a plate amplifier for this.
Is it feasible to just make a second order passive filter at the resonant peak, using that peak for impedence calculations?
Not sure if the nominal paralleled 4 ohm rating would work.
I do have an active 4th order fixed line level crossover available that has a built in 2nd order highpass at 32 hertz, but would prefer to only use a plate amplifier for this.
Using passive filters around 30hz can get very expensive very fast, even 300hz can be quite costly.
Not to mention that you waste a fair bit of power/headroom from your amplifier, even if it is "oversized" it might not be if you use passive filters that low.
It is possible, yes, but perhaps not the best solution.
If you already have an active filter setup it will most likely be far superior to any passive.
Not to mention that you waste a fair bit of power/headroom from your amplifier, even if it is "oversized" it might not be if you use passive filters that low.
It is possible, yes, but perhaps not the best solution.
If you already have an active filter setup it will most likely be far superior to any passive.
If you use your smartfone as a sound source you can install for free a 15 or 32 band equalizer like "Extra EQ" (you have to test the software for sound quality) and then you can correct any given enclosure for your drivers to your delight.
You can install for this purpose a measuring tool "Spectroid" and play a sound file with pink noise with a second smartfone feeding your amplifier. Or you have on a CD a pink noise track.
The measuring with a smartfone might not be 100% exact but the frequency response is only a first hint for adjusting bass level as a linear frequency response. In the end your ear judges if there is still some db to be corrected.
You can install for this purpose a measuring tool "Spectroid" and play a sound file with pink noise with a second smartfone feeding your amplifier. Or you have on a CD a pink noise track.
The measuring with a smartfone might not be 100% exact but the frequency response is only a first hint for adjusting bass level as a linear frequency response. In the end your ear judges if there is still some db to be corrected.