OMNIFEX said:- 3dB @ 19.7 Hertz
i dont understand the -3db bit
514 Liters (Outer Dimensions)
fB = 20Hz
meaning?
94.5 - 95.5 dB from 21.6 - 37 Hertz (2.83 volt)
meaning?
Two 15 inch woofers. (8 ohm each)
which ones?
A little under $200.00 for both woofers. (Your
saving 100 pounds!!!)
my budget is £200
What do you think?
is this good? im a complete newbie to audio.
It has very low efficiency but will play some very low bass.
DPL12
http://www.adireaudio.com/diy_audio/drivers/adire/dpl12.htm
Big box too.
DPL12
http://www.adireaudio.com/diy_audio/drivers/adire/dpl12.htm
Big box too.
OMNIFEX said:
I disagree. If you can build a stout box, a sub is a very good project to get your feet wet -- and you can save big bucks over a commercial unit.
And i would advise always using a pair of drivers (in push-push) instead of a single 12.
2 x 12 instead of a 15
2x15 instead of an 18
Value for the $$ it is hard to beat 12" because the market segment is VERY competitive.
A sealed (or aperiodic) box with room gain is going to sound better than a ported enclosure. If you can afford the volume a TL is nice too.
And remember Hoffman's Iron Law. Low Bass, Small Box, and high efficiency just don't go together.
dave
Matttcattt said:
A taken to extremes example:
An externally hosted image should be here but it was not working when we last tested it.
There has been a lot of talk about push-push -- do a search.
Transmission Line
example:
An externally hosted image should be here but it was not working when we last tested it.
Wll Low Bass, Big Box, Low Efficiency go together?
Yes.
dave
i got an idea.
2 x 12" push push for bass topped by...
2 x 6" push push (baffle step comp) for mid...and...
1 x 1" for everything else (2k+)
Q1: when doing 2 x 6" push push (80Hz+) does one have to use a series L with the rear woofer to roll it off or does having the 2nd woofer facing the rear do that anyway?
Q2:how much distance between 2 woofers in a push push? 12", 15"?
Q3: for a push push TL using 2 x 12" and expecting a F3 of 30Hz wont the box be huge (I am thinking of using audio concpets DV12s).
Q4: for 2 12" side by side Sd doubles hence voice coil has to move half distance for same SPL hence more linear bass does the same apply to push push.
2 x 12" push push for bass topped by...
2 x 6" push push (baffle step comp) for mid...and...
1 x 1" for everything else (2k+)
Q1: when doing 2 x 6" push push (80Hz+) does one have to use a series L with the rear woofer to roll it off or does having the 2nd woofer facing the rear do that anyway?
Q2:how much distance between 2 woofers in a push push? 12", 15"?
Q3: for a push push TL using 2 x 12" and expecting a F3 of 30Hz wont the box be huge (I am thinking of using audio concpets DV12s).
Q4: for 2 12" side by side Sd doubles hence voice coil has to move half distance for same SPL hence more linear bass does the same apply to push push.
Matttcattt said:
You want the drivers as tightly connected as possible mechanically as you can get so as to cancel as broad a range of Newtonian force as possible (every action has an equal & opposite reaction). Usually, a piece of hardwood between the magnets is what gets used. A block of solid aluminum or brass would probably be better. Magnet directly to magnet is best.
The picture above is the concept taken to extremes.
It is a very rare driver that allows you to bolt the drivers together thru the pole-piece. Note that on the PR-2s the magnet is inside the basket and the driver was designed to have a lag bolt thru the polepiece to screw it into a brace in the cabinet -- bolting it to another speaker is an extension of that use.
If you tried to bolt 2 drivers together that didn't have the basket enclosing the magnet, the possibility exists that you could pull the magnets loose.
dave
Matt, don't bother with any of the drivers from Maplin (I work there btw LOL), they are all PA, ie VERY efficient and don't go as low as most 6.5's. 
Goto BK Electronics and get yourself a couple of BSB 10-500's, awesome woofers, only 10" but they have a P-P excursion of almost 50mm and they're only £130.
I built a sub for a friend recently, using 2 BSB 10-500's in a sealed box, with each woofer on an opposite side of the enclosure (cancel each others vibrations) in push-push with a Linkwitz transform and 1000w amp.
They can reach into the mid 20's happily, but their fotre' is making the place shake
Goto BK Electronics and get yourself a couple of BSB 10-500's, awesome woofers, only 10" but they have a P-P excursion of almost 50mm and they're only £130.
I built a sub for a friend recently, using 2 BSB 10-500's in a sealed box, with each woofer on an opposite side of the enclosure (cancel each others vibrations) in push-push with a Linkwitz transform and 1000w amp.
They can reach into the mid 20's happily, but their fotre' is making the place shake
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