From the Eminence website:
http://www.eminence.com/eminence/pages/products02/new/newfor2004.htm
"We are also now offering a 10" version of the LAB12 called the HL-10A. This speaker is great for horn-loaded applications."
http://www.eminence.com/eminence/pages/products02/new/newfor2004.htm
"We are also now offering a 10" version of the LAB12 called the HL-10A. This speaker is great for horn-loaded applications."
mikee12345 said:
inefficient woofer + PR needed ?
Plugged numbers into Bullock and White's DOS BOXMODEL. Those Thiele-Small numbers add up to a senstivity of of 87.1@1W/1M. Not bad at all.
mikee12345 said:
32hz with 1 cubic ft =smoke stack ports
PR would be helpful. Might be fun calculating how much space the port for a Ported Box would take up.
I'd try a 90mm vent, which would only need to be 600mm, which is still quite long, but not too bad. And I would use very generous flares. Or use a downfiring port with a smaller than usual clearance designed to lower the effective tuning by 2 - 4 Hz. So the 90mm vent could then be nominally tuned at say 36 Hz, and be 460mm long, which isn't as bad at all. I know of a local speaker builder who uses this technique, although I haven't tried it myself.
I'm already anticipating some will say that it will have "one note bass," perhaps it is a knee jerk reaction, perhaps it is true, but it's worth a thought.
regards,
Paul
I'm already anticipating some will say that it will have "one note bass," perhaps it is a knee jerk reaction, perhaps it is true, but it's worth a thought. regards,
Paul
Flares are significant.
I have not yet used them.
My understanding is that a port flared on both ends is equivalent to a straight pipe of double it's area-not double it's diameter, double it's area.
So a 2" flared pipe is about equivalent to a 3" straight pipe, a 3" flared pipe is approximately equivalent to a 4" straight pipe.
I wonder if downward firing ports, even those with normal spacing to the ground, do not couple the port output to the ground so well that smaller diameter vents can be used. Just a guess.
I have not yet used them.
My understanding is that a port flared on both ends is equivalent to a straight pipe of double it's area-not double it's diameter, double it's area.
So a 2" flared pipe is about equivalent to a 3" straight pipe, a 3" flared pipe is approximately equivalent to a 4" straight pipe.
I wonder if downward firing ports, even those with normal spacing to the ground, do not couple the port output to the ground so well that smaller diameter vents can be used. Just a guess.
kelticwizard said:
Yes flares are significant. With my AV12 subs, they are absolutely essential, cos my AV12 is blumin' hard to design for a vented box! (if you want it as small as possible as I do).
I have experimented with flares quite a lot. In fact, I made three different flares turned on the lathe out of MDF, one using a single layer of 18mm MDF, one used 2 layers, the third used 4 thicknesses and has a very large radius. I placed a 2 layer flare (radius = 36mm) on the inside, and then placed the three different flare sizes on the free end when there was a 15 Hz tone playing, which is normally quite loud when the cone is moving say 35mm. There was significant improvement for the 18mm flare over having nothing, then a tiny improvement with the 36mm flare, and I think a tiny improvement with the 72mm flare, although it is actually hard to judge.
For a downward firing vent to achieve a lower tuning point (effectively 2-4 Hz lower), the clearance under has to be relatively small - say 35 - 50mm for a 100mm vent. This can introduce problems as if you have a vent without a flare and have it downfiring, the increase in turbulence is dramatic. A smaller vent would not be advisable. This is in fact where flares need to be larger. This is where the 72mm flare radius becomes necessary.
The beauty of downfiring the vent in this way, as I see it, is that you can make the nominal tuning higher, and avoid a vent that is so long that it will have unwanted resonances. I threw a 1m 100mm vent in my 70L test boxes so they were tuned at about 18 or 19 Hz and when you tap the cone, the vent whistles - but I didn't want to cut up the vent til I had made a few decisions. I haven't yet determined if the downfiring vent idea is really going to work.
regards,
Paul
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