simon5 said:
thanks simon5.
it is hooked up right now in my car powered by an old school rockford amp. the enclosure is 2.25 cu ft, slot ported tuned to 28 hz as per JL specs.
now i am confident to buy a plate amp. plate amps are very rare in the philippines. i have to get mine from the US or get it from a diy'er who's selling a decent one though.
I used a 10" JBL GT4 http://www.motor-world.co.uk/show_prod.php?prod_id=5449 to extend the range of my PMC DB1+s. The box is undersized to produce a system resonance of 51Hz and is then equalized using a double integrator as per http://sound.westhost.com/project48.htm. The internal volume is only 18.1 litres less the basket. The undersized box / double integrator is subject to a patent. http://www.audioannals.com/04481662-Long-Wickersham-txt.htm The full document is available if you use "DjVu" http://www.djvuzone.org/download/index.html
(My understanding is that patents are effective for 20 years, so this one is no longer active).
This is a novel and (apart from the amplification) inexpensive way to extend the range of your main speakers. The double integrator equalizer means that the speaker needs 12db more power at 25Hz than at 50Hz, but 12dB less power at 100Hz than at 50Hz. This is a narrow band of operation so power requirements are not as great as you might first suspect.
I don't see any disadvantage in using a car sub for this project!
Tony
(My understanding is that patents are effective for 20 years, so this one is no longer active).
This is a novel and (apart from the amplification) inexpensive way to extend the range of your main speakers. The double integrator equalizer means that the speaker needs 12db more power at 25Hz than at 50Hz, but 12dB less power at 100Hz than at 50Hz. This is a narrow band of operation so power requirements are not as great as you might first suspect.
I don't see any disadvantage in using a car sub for this project!
Tony
An externally hosted image should be here but it was not working when we last tested it.
This remind me of a rather perverted idea i struggle too lay off my mind.
I have 2 of these:
http://www.rockfordfosgate.com/rftech/library/1998/5_Subwoofers/RFR2212-TS.pdf
and 2 of these:
http://www.rockfordfosgate.com/rftech/library/1998/5_Subwoofers/RFR2215-TS.pdf
A pair of midwoofer called Macrom Integra 224W (8,5")
and finally a pair of Morel 28mm tweets.
The idea are as following:
15" in separate boxes. 160L tuned to 23 hz (up too 50hz)
12" used as low midbass in 35L sealed (50-120hz)
8,5" in 25L sealed (from 120-3000hz
and the tweets from there and up.
Bi or maybe even triamped (eventually with hipower Plate amps on the woofers)
Maybe a tad expensive too build, but migth be worth it
Or what?
Attached pic are just a rough drawing, done with paint
I have 2 of these:
http://www.rockfordfosgate.com/rftech/library/1998/5_Subwoofers/RFR2212-TS.pdf
and 2 of these:
http://www.rockfordfosgate.com/rftech/library/1998/5_Subwoofers/RFR2215-TS.pdf
A pair of midwoofer called Macrom Integra 224W (8,5")
and finally a pair of Morel 28mm tweets.
The idea are as following:
15" in separate boxes. 160L tuned to 23 hz (up too 50hz)
12" used as low midbass in 35L sealed (50-120hz)
8,5" in 25L sealed (from 120-3000hz
and the tweets from there and up.
Bi or maybe even triamped (eventually with hipower Plate amps on the woofers)
Maybe a tad expensive too build, but migth be worth it
Or what?
Attached pic are just a rough drawing, done with paint
Attachments
Hi again, I just got a couple of Infinity Reference 1230 12 inchers.
VOICE COIL DC RESISTANCE: REVC (OHMS) . . . . . . 3.40
BL (TM) . . . . . . . . 14.63
VAS (LITERS) . . . . . 78.50
CMS (µM/N) . . . . 195.40
MMS (GRAMS). . . . 174.21
MMD (GRAMS) . . . 167.15
FS (HZ) . . . . . . . . 27.27
QMS . . . . . . . . . . . 6.14
QES . . . . . . . . . . . . 0.47
QTS . . . . . . . . . . . . 0.44
XMAX (MM) . . . . . . 12.25
What can I do with them for a home theatre subwoofer?
VOICE COIL DC RESISTANCE: REVC (OHMS) . . . . . . 3.40
BL (TM) . . . . . . . . 14.63
VAS (LITERS) . . . . . 78.50
CMS (µM/N) . . . . 195.40
MMS (GRAMS). . . . 174.21
MMD (GRAMS) . . . 167.15
FS (HZ) . . . . . . . . 27.27
QMS . . . . . . . . . . . 6.14
QES . . . . . . . . . . . . 0.47
QTS . . . . . . . . . . . . 0.44
XMAX (MM) . . . . . . 12.25
What can I do with them for a home theatre subwoofer?
Tony
I would put each one in a 35 litre box (undersized) and equalize with this:
http://sound.westhost.com/project48.htm
or this:
http://sound.westhost.com/project71.htm
depending on where your main speakers roll off. (See my post above).
Tony
I would put each one in a 35 litre box (undersized) and equalize with this:
http://sound.westhost.com/project48.htm
or this:
http://sound.westhost.com/project71.htm
depending on where your main speakers roll off. (See my post above).
Tony
I have got a US blaster usb-2100, seen in most stores for 419 euro, I bought in on sale for 60 euro's (and 10 euro's shipping ).
Check it out here: http://www.xs4all.nl/~loosen/us blaster subwoofer/
It's designed to play in a ported box of about 50 liter, in which it can have an f3 of about 32 hertz.
Closed is absolutely horrible because of the low vas.
I don't care if it's a car woofer or not, for 419 euro's it just can't be bad.
).Check it out here: http://www.xs4all.nl/~loosen/us blaster subwoofer/
It's designed to play in a ported box of about 50 liter, in which it can have an f3 of about 32 hertz.
Closed is absolutely horrible because of the low vas.
I don't care if it's a car woofer or not, for 419 euro's it just can't be bad.
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