Advice on drivers for Sub-woofer

[darrylis]

Thanks everyone for the suggestions. I'll make a choice and go from there.



My intention is to build one for the learning experience.

 

[darrylis]

Question on cabinet volume. Given that I will be purchasing this driver as suggested by Norman Dayton Audio DCS255-4 10" Classic Subwoofer 4 Ohm

and a design target of:

50l. (1.74ft3)
F3. 31hz
Tune 33hz
4" port. 14.6" long

I'd like to know how to factor in the additional volume required to compensate for damping, cone, flare? etc., if I've to get to net 1.74 cuft3.

I may use this to dampen the innards of the cabinet. https://www.homedepot.ca/product/rockwool-safe-n-sound-16-inch-o-c-for-2x4-wood-studs/1000421954

The density of this is 2.5 lb/ft^3, if that's useful, according to Comparing the Best Soundproofing Insulation Products • Soundproofing Tips

I also have polyfil, should I have any preference of one over the other ?

Also, I believe this is the port I should be getting PSP4-BKHT - Solen Electronique Inc.

In case I want to build the port into the wood, I'm assuming an opening of 3.14 * (4/2)^2 = 12.56 inch^2 is the correct opening area (since 4" is the diameter).

Please advise, thanks in advance.

 

[norman bates]

On a sub, i never add stuffing, not worth the money.

A 12" is around .125ft3, so maybe .1 ft3 ?

Subtract for the port too.

It wont be exact, there is a bit of variance in the drivers too.

 

[42476]

SB Acoustics SB23MFCL45-4, 8" Sub Woofer

I have this in the 4 Ohm version. With a plate amp, EQ, boost, etc. and in only 1 ft^3 closed box, it goes LOW! I have an in-room response down to 14 Hz! It is a really very well designed and built smaller sub-woofer but could put some 10 inch and even some 12 inch woofers and sub-woofers to shame! I haven't tried to calculate, model or sim. WITHOUT a plate amp with bass management though.

 

[norman bates]

Sealed .4ft3, f3 = 54hz
Ported .74ft3 f3 =32hz, tune 34
Speaker Box Enclosure Designer / Calculator

 

[42476]

Box recommendations:

Sealed box of 0.4 to 0.5 cubic feet for an F3 of 65Hz. You would need to use a bass boost or DSP to push the driver into lower frequencies. The F6 is 45Hz and F10 is 35Hz.

Vented box of 0.8 to 1.0 cubic feet with a 2" port by 8" long for an F3 of 35 to 32Hz.

For my SB sub; recommendations from the Madisound site. Many alignment choices for sure. I went with closed box because I already had the plate amp. It has many bass management features and controls.

Here are some other useful calculators:

HiFi Loudspeaker Design

They have added some newer calculators; These are very handy because you can easily compare sealed to vented; ideal to custom box size; the 3 most common vented alignments with the Ql choices of 3, 7 or 15. You can also quickly see what happens if you increase Qt due to the DCR of crossover inductors, wires, cables, etc.

 

[darrylis]

In the past I've heard about the Eminence 15a being used in an open baffle configuration.



Can anyone advise on the whether I can touch 30Hz and the size of the baffle.

 

[ProperOperation]

I'm curious to hear how your project is going. I'm pretty much on the exact same path. currently leaning toward the Dayton DCS305-4 with the SA-100 or SPA250 plate amp.

 

[Booger weldz]

Accurate ?

People get hostile over that one.
To me the phase angle wrap at the subwoofer point is where you hear problems.
I stuffed my 15s' port (tuned 27hz).
It wasn't any faster than the ported, just an octave less bass.
I think tuning 30hz and below is fine.
Even on the books, the transient response is the same as a sealed an octave above tuning.

I'd swear there was a 12" dayton that would have ported around 2.5ft3 and 25hz tuning.

Rss265ho4, 85 liter offset driver QW pipe maybe? (Ignore the highlights and arrows).

 

[waxx]

The 8" Dayton RS225-4 can do that. A 1 3/4 cuft with a 4" port of 17" 1/8 long will do it. This is a rough calculation of course. You can get this driver to 102dB roughly at that frequency, so it should do it in most cases. And the driver is good and cheap ($59.98 at parts express).