JL Audio 12" W6 Design Support Needed

[ma7rix13]

Was looking at building a W7 via Simple Infinity Kappa Sticky but ended up getting some first generation W6's from my buddy. I am still very undecided in terms of building sealed vs. ported. Using WinISD and reviewing several other sealed designs (zaphaudio, The Drake, etc.), it seems I can "design" my own with slightly higher confidence in the result (as compared to ported).

Sealed (win isd'ish recommended):
With 3.75ft^3; Fsc is 34.62 Hz, Qtc = .705, F3 = 35 Hz. Excursion is 'maxed' around 46 Hz but the impedance spike should compensate (i think, using 300 Watts).

Sealed (JL Audio recommended):
With 1.25ft^3; Fsc ia 51 Hz, Qtc = 1.00, F3 = 40 Hz. Seems way to high for home use. I assume JL is compensating for car gain here.

Ported (Using Infinty Kappa Specs):

With 7.32 ft^3; Tuning freq = 15 Hz, Port Resonance 123Hz, F3 = 22 Hz. However, cone excursion is off the charts (22mm @ 22 hz). This design seems infeasible for these drivers.

Any help would be great. Planning on using Behringer ep4000, 2500, or 2000. Thinking about 4000 to allow room for expansion.

Size does not matter (well, for box size), looking for nice, clean bass for music and HT, not looking for spl whatsoever.

thanks,
Paul

 

[annunaki]

This driver presents a tricky alignment. It requires a lot of balance from a number of different perspectives.

It ultimately depends upon how large of an enclosure you can live with, but the most suitable alignment I can come up with is a 5.5ft^3 net enclosure tuned to 21hz. This yields an anechoic f3 of 23hz at about 107.2db with 200 watts rms. It does allow +/-3db response from 23hz-79hz between 107.2db and 110.2db. A single slot vent of 2.5" x 14" x 33.875" will allow vent velocities well below 17m/s.

One can get a 3hz lower f3 at the cost of 2.5ft^3 increase in enclosure size and a 2hz lower tuning frequency but it increases excursion further past xmax. And it increases enclosure size by 2.5ft^3!!!!!


This driver in this alignment requires a lot of assumptions however.

#1 It MUST use a 20hz infrasonic filter of at least 12db/oct (2nd order)

#2 It MUST NOT have much if and power above 200 watts.

#3 Excursion limits are easily reached which is why input power must be lower
The above alignment assumes the driver to allow +10% above linear xmax prior to audible distortion setting in.




All in all a single 12W7 would easily equal or surpass nearly 3 of these 12" drivers looking at displacement numbers alone. It would also do so with lower overall distortion to boot.

You can do this project but it will be very limited in what you can accomplish. A Dayton RSS315HF would easily outperform this driver now days for a touch over $100.00.

15 years ago this was one of the best drivers in the market place. Technology has moved on. Though I am fond of JL's products there is a reason why this driver now no longer produced, it is simply obsolete. Even the base model W1v2 series offer's a higher level of performance now with improved linearity.

 

[ma7rix13]

Thanks. I really needed another opinion...

I think I will just build a sealed enclosure with a EP4000 as a temporary setup and then upgrade to the W7's or something more 'modern' sub in the future. (right now I am using a Infinity 8" BU-1) so this should be a nice upgrade for the time being.

What do you think about the sealed design? Is it reasonable for a temp setup?

 

[ma7rix13]

Oh yea, forgot to mention. I have 2 of these for a left/right config...

 

[annunaki]

I would suggest the vented option here.

The sealed option will begin exceeding xmax at around 42 hz making it useless in the home for any sort of theater use below this frequency.

 

[ma7rix13]

But around 40Hz the impedance is 10 ohms. Shouldn't this compensate for the 'lack of excursion'. [Note: this logic was developed from Zaph's 12" Dayton sub build in his archives section, http://www.zaphaudio.com/archives.html]

 

[annunaki]

But around 40Hz the impedance is 10 ohms. Shouldn't this compensate for the 'lack of excursion'. [Note: this logic was developed from Zaph's 12" Dayton sub build in his archives section, http://www.zaphaudio.com/archives.html]

No since the driver is at excursion limits and more at that frequency. Sure the actual input power rolls back due to impedance but the sub is still moving past limits.

 

[lsiberian]

Get the Dayton drivers or look around for the Infinity Perfect series. Sometimes they are on craigslist for around 50 bucks.

 

[ma7rix13]

Yea, I have abandoned this W6 project. I just ordered a JL 13w1v2 and Behringer 2000. I have a four day weekend and should have the box built by Monday. Be on the look out for a new build thread!