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Old 26th February 2003, 09:46 PM   #1
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Location: USA
Default pro-subwoofer question

I have not worked on speakers in forever... I just became happy with my system and accepted the fact that I would never need to build more speakers though I still want to deep down.

Anyway, I have been commissioned by a friend to build a subwoofer for him that will give a lot of output. So, Why not use a pro-sub? Would it just be bad?

I have done most everything I need to do for it... it will be this:

18"W x 18"D x 30"H
Volume= 5.625 cu. ft.
using one Eminence Delta-12LFA
tuned to 25Hz via 4.00"W x 7.15"L port

Is this tuning frequency too low? It says 45Hz is its lowest, but that isn't true for any speaker...

Would this work and give some serious output with this amp?

The idea is to get max output for least money... What do you think of this?
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Old 26th February 2003, 10:03 PM   #2
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Location: Mars
These are popular woofers for sub-duty. There are others
of course.

12" Shiva
http://www.adireaudio.com/diy_audio/...dire/shiva.htm

15" Tempest
http://www.adireaudio.com/diy_audio/...re/tempest.htm

15" Tumult
http://www.adireaudio.com/diy_audio/...ire/tumult.htm

18" Maelstrom (higher sensitivity rated, lower excursion)
http://www.adireaudio.com/diy_audio/.../maelstrom.htm

You can find white papers on these woofers with
completed cabinet designs.

Talk to John @ Stryke for tips, he has some new
AV12 and AV15 woofers that look amazing too.
http://www.stryke.com/

These woofers are a higher calibur than the Eminence brand,
but they may require a little more power to drive well.

If money is an issue, then the Eminence may be your
only option.
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Old 27th February 2003, 06:15 PM   #3
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The NHT 1259 would also be an excellent choice for this application. With the volume you've got, you wouldn't even need the port.
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Old 1st March 2003, 08:18 AM   #4
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Default pro sub

The thing is..
using a pro speaker normally it is higher efficency meaning u dont need as much power..

.dont tune below resonance.


eg i wud rather a 94db/1watt speaker with 30hz resonance
than a 88db speaker with 18hz resonance (1x12inch wont do 18hz particulry well unless it has a kw of power.

u want the most output for smallest money? Dont go super low freq or ul be inefficent generally.

>eminence is high resonance high efficiency.


ive heard good things about the NT1259
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Old 1st March 2003, 12:13 PM   #5
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Pro sound drivers have more distortion, and this will definitely be noticeable in a side-to-side comparison of two subwoofers, one subwoofer using a pro sound driver and one subwoofer using one of the drivers listed above.

The reason for this is that pro sound subwoofers are not completely linear in their travel. They have a good deal of suspension excursion but only 4-5mm of that is actually linear (that is, where the motor has control over the cone.) This is because PA drivers are only supposed to be loud and sound decent, not be musical and tight. You really do not want one of these PA woofers for high-fidelity sound, only for high-output Pro Audio applications where the driver has to play loud, semi-controlled, and not blow up when a large power transient enters it. Pro sound subwoofers also in general have a high free air resonance frequency, and do not have a frequency response that goes below 30Hz (until you get into the 18" woofers.) You want response down to 25Hz or 20Hz if you can get it, but you won't get it from a PA driver.

Adire Audio uses a special version of a 10" PA woofer in one of their designs. The woofer has a large vent in the pole piece which allows a coaxial tweeter to be added. But the PA woofer in question is made differently from the off-the-shelf version of the same model woofer from Eminence.
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Old 1st March 2003, 01:30 PM   #6
Wizard of Kelts
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Location: Connecticut, The Nutmeg State
The link to the amp does not work. Is this amp a four ohm amp or an eight ohm amp?

Reason: If you hook two 8 ohm speakers in parallel to form a 4 ohm unit, their sensitivity rating goes up 6 dB. So two eight ohm speakers rated at 88 dB, when hooked up in parallel, will actually be 94 dB and will give full power when hooked up to a 4 ohm amp. (When they are hooked up to an 8 ohm amp, that is another story).

Naturally, when you hook two speakers up in parallel, you must double the volume of the box to get the same F3 cutoff.
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