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Emile

DIY bass bins - dual 12" woofers

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Hi All,

 

Hoping to get some advise.  Trying to duplicate the sound of my KPT-904's (OK; get "close" to their sound) for use in a small (12x12x8') stereo room. Have an extra pair of K-510's (w/ B&C 75 drivers) which I will use separately (via DSP) with these bass bins. Tried finding CF4's, but no luck. Still talking with a CF3 seller, but the guy is a major pain ... wants top dollar for a "version 3" set, which is the worst of the series.

 

So; why not build a couple of boxes? Thinking ported/slotted, very roughly 18x16x36", of course with pro woofers. Would like the box to go down to say 40Hz.  Upside is taken care of by the 510 horns, kicking in at 500-600Hz. Looking at Eminence Delta 12LFC ( https://www.parts-express.com/eminence-delta-12lfc-12-driver-4-ohm--290-464 ), but I am sure you may have better suggestions :D Just picked up a Crown XLS 402 (300wpc at 8Ohms) to drive them.

 

OK; have NOT found any design plans and also NO calculator for dual woofer bins.

 

Appreciate your help :D 

 

Many thanks, Emile

 

Add-on ... yes, know you will recommend something like KPT-684's ... unfortunately just do not have room for those beasts :( 

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Dual woofers are easy, double everything. 

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2 minutes ago, JohnA said:

Dual woofers are easy, double everything.

Haha ... didn't think it was that easy :D  But now I know, don't have to buy $100 software. :D Thanks!

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3 minutes ago, jason str said:

Look for the large vented cabinet. >here<

Jason, Thanks!  Shows Vtot = 3.5 cuft.  So in my case I'd go to 7 cuft or roughly 18x18x36 which is "doable" in this small room :)  OK; assume Vtot is INTERNAL  dimension, without the ports? 

Cheers, Emile

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I would do 4 corner ports personally.

 

Corner triangular ports will strengthen the cabinet and reduce turbulence.

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Looks like a good choice except that it is limited to 10 watts at 40 Hz.  Need to use a good filter at 40 Hz. 

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@Emile   This lets you pick the drivers (or enter new driver parameters), and the number of drivers... lots of options.

 

WinISD   http://www.linearteam.org/

 

Cheers!

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25 minutes ago, JohnA said:

good choice except that it is limited to 10 watts at 40 Hz

John, thanks!  But have "no clue" what that means :(  Could you explain?

Many, many thanks, Emile

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What about JWCs DBB?

OK they're 15"s but hey you're worth it:)

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8 hours ago, Emile said:

John, thanks!  But have "no clue" what that means :(  Could you explain?

Many, many thanks, Emile

 

All drivers have a travel limit (Xmax).  All drivers need more travel as frequency drops (and it increases at the rate of 12 dB/octave) to maintain output.  In this case, the driver hits its travel limit about 40 Hz and due to the box tuning, it only takes 10 watts to hit Xmax  at 40 Hz.  I think it takes 2 watts at 35 Hz.  Now, that's no problem if you turn on a 40 Hz high-pass that is at least -12 dB/octave.  -12 dB/octave will cut the power below the filter "knee" as fast as the cone travel increases preventing damage. 

 

One of the graphs in Jason's link shows the max allowable power per frequency, based on cone travel. 

 

Xmax is the max travel allowed in one direction.  Twice Xmax is the total travel out to in. 

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15 hours ago, Emile said:

Hi All,

 

Hoping to get some advise.  Trying to duplicate the sound of my KPT-904's (OK; get "close" to their sound) for use in a small (12x12x8') stereo room. Have an extra pair of K-510's (w/ B&C 75 drivers) which I will use separately (via DSP) with these bass bins. Tried finding CF4's, but no luck. Still talking with a CF3 seller, but the guy is a major pain ... wants top dollar for a "version 3" set, which is the worst of the series.

 

So; why not build a couple of boxes? Thinking ported/slotted, very roughly 18x16x36", of course with pro woofers. Would like the box to go down to say 40Hz.  Upside is taken care of by the 510 horns, kicking in at 500-600Hz. Looking at Eminence Delta 12LFC ( https://www.parts-express.com/eminence-delta-12lfc-12-driver-4-ohm--290-464 ), but I am sure you may have better suggestions :D Just picked up a Crown XLS 402 (300wpc at 8Ohms) to drive them.

 

OK; have NOT found any design plans and also NO calculator for dual woofer bins.

 

Appreciate your help :D 

 

Many thanks, Emile

 

Add-on ... yes, know you will recommend something like KPT-684's ... unfortunately just do not have room for those beasts :( 

Emille. Don't you think I already modeled it before I gave you the advice? Insulting as this may be, I'm sorry I wasted my time. So you go ahead and seek other variable wrong or right "opinions" and see what "maybe" comes out OK. Below is a double size Super Heresy with twin bass ports 2 volt drive, as prescribed in PM.

DoubleStackSuperHeresyDeltaPro12A.jpg

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15 hours ago, Emile said:

So; why not build a couple of boxes? Thinking ported/slotted, very roughly 18x16x36", of course with pro woofers. Would like the box to go down to say 40Hz

 

You really don't need dual woofers and why re-invent the wheel?  Here is exactly what you need, a pair of flat packs for mid bass modules.  These go down to 30 Hz.

 

https://www.diysoundgroup.com/home-theater-speaker-kits/home-theater-extras/midbass-modules.html

 

If you're not familiar with DIYsoundgroup and their excellent products which are sold slightly above cost, let me know and I'll fill you in on the best kept secret in DIY speakers.

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5 hours ago, JohnA said:

 

All drivers have a travel limit (Xmax).  All drivers need more travel as frequency drops (and it increases at the rate of 12 dB/octave) to maintain output.  In this case, the driver hits its travel limit about 40 Hz and due to the box tuning, it only takes 10 watts to hit Xmax  at 40 Hz.  I think it takes 2 watts at 35 Hz.  Now, that's no problem if you turn on a 40 Hz high-pass that is at least -12 dB/octave.  -12 dB/octave will cut the power below the filter "knee" as fast as the cone travel increases preventing damage. 

 

One of the graphs in Jason's link shows the max allowable power per frequency, based on cone travel. 

 

Xmax is the max travel allowed in one direction.  Twice Xmax is the total travel out to in. 

 

Best to use a 24 dB/octave high pass filter to protect the woofer.

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8 hours ago, justinsweber said:

Mini Punch 🙂

Yea I still cannot get a hold of GotHover, I must be on his S@#t list. Will he make somebody a kit of these?

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23 hours ago, Emile said:

Hi All,

 

Hoping to get some advise.  Trying to duplicate the sound of my KPT-904's (OK; get "close" to their sound) for use in a small (12x12x8') stereo room. Have an extra pair of K-510's (w/ B&C 75 drivers) which I will use separately (via DSP) with these bass bins. Tried finding CF4's, but no luck. Still talking with a CF3 seller, but the guy is a major pain ... wants top dollar for a "version 3" set, which is the worst of the series.

 

 

 

OK; have NOT found any design plans and also NO calculator for dual woofer bins.

 

Appreciate your help :D 

 

Many thanks, Emile

 

Add-on ... yes, know you will recommend something like KPT-684's ... unfortunately just do not have room for those beasts :( 

 

I would either go with Claudes advice and build a double Super Heresy Cabinet or go the KLF-30 bass bin route with the Ciare woofers

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