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[Paul Lea]

I know, another thread about home brew subs...... sorry in advance. 

I have 20 of the P. Audio Clones of the JBL 2241H 18" drivers.  They are loaded into old Cerwin Vega cabs that are pretty much one note wonders and they are falling apart.  The drivers are all in good shape and most have been reconed over the past two years.

I am trying to find out what box specs I would need to build to make them into a standard dual 18" front firing setup.  I would have to believe that in the right box they would be more tunable and also take up less space in a truck.

Anyone ever built a box these drivers and care to share the box design?

[Paul G. OBrien]

Anyone ever built a box these drivers and care to share the box design?

A quick and dirty solution would be to simply copy the dimensions of the JBL SR4719 and bolt the drivers in, however a better solution would be to plug the T/S specs for the clones into WinISD Pro to generate a box size and tuning and then just build to that spec. Note that the larger and lower tuned the box is the less power the drivers will handle.

[Jon Geissinger]

A quick and dirty solution would be to simply copy the dimensions of the JBL SR4719 and bolt the drivers in, however a better solution would be to plug the T/S specs for the clones into WinISD Pro to generate a box size and tuning and then just build to that spec. Note that the larger and lower tuned the box is the less power the drivers will handle.

I agree with Paul. Build newer versions of the same box.

[Stu McDoniel]

I know, another thread about home brew subs...... sorry in advance. 

I have 20 of the P. Audio Clones of the JBL 2241H 18" drivers.  They are loaded into old Cerwin Vega cabs that are pretty much one note wonders and they are falling apart.  The drivers are all in good shape and most have been reconed over the past two years.

I am trying to find out what box specs I would need to build to make them into a standard dual 18" front firing setup.  I would have to believe that in the right box they would be more tunable and also take up less space in a truck.

Anyone ever built a box these drivers and care to share the box design?

Check your theile small parameters on your drivers and compare it these Selenium
18" drivers..  One of these sub boxes might work just fine for you

http://www.parts-express.com/mfg/selenium/selenium-cabinet.cfm

[Iain.Macdonald]

I know, another thread about home brew subs...... sorry in advance. 

I have 20 of the P. Audio Clones of the JBL 2241H 18" drivers.  They are loaded into old Cerwin Vega cabs that are pretty much one note wonders and they are falling apart.  The drivers are all in good shape and most have been reconed over the past two years.

I am trying to find out what box specs I would need to build to make them into a standard dual 18" front firing setup.  I would have to believe that in the right box they would be more tunable and also take up less space in a truck.

Anyone ever built a box these drivers and care to share the box design?

Hi,

Which P Audio driver do you have? I don't agree with the idea of just building a copy of the JBL box, or a newer CV box. The reason for the one note wonder is possibly because the CV box is not correct for the P Audio driver. Just because the P Audio looks like a JBL driver does not mean that it is the same.

Iain.

[Paul Lea]

This is the P-Audio Driver, http://www.usspeaker.com/homepage.htm

Billed as a clone of the 2241 by P-Audio themselves.

I am nearly certain the Driver was not matched correctly to the old CV box, the previous owner had done this. Then used tunings for the EAW Sb1000 to run it.  Not my favorite sub sound.

I figured since the P-audio was a JBL Clone, might as well build the box that JBL had originally built for it.  Of course, this only applies if the P-Audio is a true replica of the JBL Driver.

[John Halliburton]

This is the P-Audio Driver, http://www.usspeaker.com/homepage.htm

Billed as a clone of the 2241 by P-Audio themselves.

I am nearly certain the Driver was not matched correctly to the old CV box, the previous owner had done this. Then used tunings for the EAW Sb1000 to run it.  Not my favorite sub sound.

I figured since the P-audio was a JBL Clone, might as well build the box that JBL had originally built for it.  Of course, this only applies if the P-Audio is a true replica of the JBL Driver.

Your link is to the front page at US Speaker.  What model number is the driver?

Never mind, I found it.

T/S Parameters:

Resonant Frequency (fs)                                 33 Hz
 
Impedance (Re)                                             5.1 ohms
 
Coil Inductance (Le)                                       1.5 mH

Mechanical Q (Qms)                                       7.11
 
Electrical Factor(Qes)                                    .31

Total Q (Qts)                                               .30
 
Comp. Equivelant Vol. (Vas)                            10.96 ft3 / 310.84 Liters
 
Effective Surface Area (Sd)                            .124 m2
 
Voice Coil Overhang (Xmax)                            5.5 mm

Reference Efficiency                                      3.47%


Fairly efficient, not much excursion at all.

Best regards,

John

[John Halliburton]

And for the two versions of the 2241:

2241G
Fs=35hz
Qts= 0.4
Qms= 5.7
Qes= 0.43
Vas= 311.5liters
Eff= 2.9%
Pe= 600watts
Xmax= 7.62mm
Re= 2.5ohms
Le= 0.86mh
Sd= 0.123
Bl=13.6
Mms= 145g






2241H
fs=35hz
Qts= 0.4
Qms= 5.7
Qes= 0.43
Vas= 311.5liters
Eff= 2.9%
Pe= 600watts
Xmax= 7.62mm
Re= 5.0ohms
Le= 1.75mh
Sd= 0.123
Bl= 19.2
Mms= 145g

Not the same beasts at all.  Almost 40% more excursion capacity in the JBL, and Qts is more desirable for a better "natural" alignment, both big game changers.

Best regards,

John

[Paul Lea]

John, thanks!  I guess I should just get WINISD and start hunkering down to see what kind of box would be best for them and start from the ground up. Should be interesting, thanks to all for the responses.

[John Halliburton]

John, thanks!  I guess I should just get WINISD and start hunkering down to see what kind of box would be best for them and start from the ground up. Should be interesting, thanks to all for the responses.

If I had 20 drivers as you do, I'd consider designing a single 18" cabinet, make the vent generously sized, and see if a good size with some truck pack dimensions on a couple of side can be laid out.

With the ever easier deployment of subwoofer arrays, twenty single 18" cabinets gives you something to play around with.    You can always configure them in a more traditional method as well if desired.

1/4x1/4x1/3=22.5"x22.5"x30ish"
1/4x1/3x1/3=22.5"x30"x30"
1/4x1/4x1/2=22.5"x22.5"x45" This may seem large, but one of the first things compromised by many manufacturers is final cabinet size-an ideal alignment will be larger than most commercial designs using the same driver.  Crunching numbers and modeling, then prototyping will let you decide. 

Put dual Speakon NL8 connectors on each cabinet, so you can daisy chain sets of cabinets using less overall cable runs.

Best regards,

John

[Derek Konop]

I know, another thread about home brew subs...... sorry in advance. 

I have 20 of the P. Audio Clones of the JBL 2241H 18" drivers.  They are loaded into old Cerwin Vega cabs that are pretty much one note wonders and they are falling apart.  The drivers are all in good shape and most have been reconed over the past two years.

I am trying to find out what box specs I would need to build to make them into a standard dual 18" front firing setup.  I would have to believe that in the right box they would be more tunable and also take up less space in a truck.

Anyone ever built a box these drivers and care to share the box design?

Are the CV boxes the semi-folded horn earthquake style? An older version of this? http://www.cerwinvega.com/pro-audio/folded-horn-subwoofer/el-36c.html

Derek

[Paul Lea]

Similar to those.  Honestly they dont do to bad of job, they just plug up to much truck space.

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