JBL4607 4507 port mod, w/wo 3015lf

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Since time is not on my side....

I can have a 4507 box, but I believe its a 4607? It has a 2225h and the two way xover in it so I assume its not set up as a sub.
Does anyone have the correct port size for the 4507 w the jbl and the modded
port size for a 3015lf handy? looking for 80-100hz and below.

Gotta either use the 2225 for now or borrow the 3015lf from another cab as a temporary solution while I build something more long term that fits in an suv.
I'll be keeping the box to go with a couple of stage monitors later along with a
gemini 400 bi amped amplifier bolted to the back.
 
Change the size of the ports (double the length). As you don't want to do this, or can't because of int. dimensions, then reduce the number of ports to half so that you have only two ports with the same length (block the other two so that you can use the speaker later).
With the JBL you had tuning to 40Hz and F3 43 Hz (JBL 2226H),
with Eminence KappaLite3015LF you have 30Hz tuning and F3 47 Hz but with better LF extension.
 
Thanks, that makes this cab look usable for now. Plugging ports is always a cool way to go keeping the cab intact.
If I were crazy enough, and if there was room, would doubling the port length via a 90 degree smooth elbow like JBL did on some studio monitors increase the overall output a couple db?
Pulling the crossover box out (if its in a box) would replace some of the lost volume.
 
1) Plugging ports is always a cool way to go keeping the cab intact.
2)If I were crazy enough, and if there was room, would doubling the port length via a 90 degree smooth elbow like JBL did on some studio monitors increase the overall output a couple db?
1)Plugging ports lowers tuning, but increases chuffing, and using a driver with higher Xmax will "blow out" the ports at high volume.
2) Doubling port length will lower Fb, output will go up slightly at the lower tuning but be reduced above.
 
1)Plugging ports lowers tuning, but increases chuffing, and using a driver with higher Xmax will "blow out" the ports at high volume.
2) Doubling port length will lower Fb, output will go up slightly at the lower tuning but be reduced above.

That will probably work as they will be under modded PV15's and crossed either 65hz via a mackie 1400I or through a tdm crossover. It'll probably get me by for the moment till life stabilizes and I can get a van. Building a pair of ss15 or even thams would be better but I don't have the luxury of a workspace anymore. Bjornosubs probably wont fit in the SUV either.
 
JBL 4507 Port Mod

Hi Y'all,

I may be looking at this all wrong, but, if the data on the ports I found @ audiokarma is correct, the port particle velocity on the unmodified 4507 is already on the high side (@ Xmax), w/ the 3015LF it gets to be clearly too high (@ Xmax). Take a look at the two attached Hornresp records, and, please, let me know what I got wrong here, or what you consider appropriate port particle velocities for PA purposes.

My guess would be 4ea. 4"Dia. x 12" long ports.

Regards,
 

Attachments

  • 4507_dims_port_2003_audiokarma_doucanoe.jpg
    4507_dims_port_2003_audiokarma_doucanoe.jpg
    58.7 KB · Views: 179
  • 1jbl4507.txt
    981 bytes · Views: 55
  • 2jbl4507.txt
    979 bytes · Views: 44
Last edited:
Oliver,

The 4507 was designed for use with the JBL 2225 which has only 5.08mm Xmax, I'd agree that almost doubling Xmax (3015LF has 9.6 mm Xmax) would require larger port volume if one wants to take advantage of the output the additional excursion avails rather than create four fan jets :^).

What Fb did you guess would result with 4ea. 4"Dia. x 12" long ports?

Art
 
Last edited:
Hi Art,

The 4507/2225H is the attached file 1jbl4507.txt in Post #9; file 2jbl4507.txt is for the same box w/ the 3015LF.

Changing the ports to 4ea. 6"Dia. x 12" long gives a Helmholtz frequency of 39.14Hz (Loudspeaker Wizard). I'll attach the simulation for the bigger longer ports using the 3015LF (note: I took 5L off the Vrc (now 140L instead of 145L), and increased Eg to 48.0 (Dd=9.6118mm @ 57.25H).

Regards,

P.S.: I found a JBL tech document for the "4647A Low Frequency System", basically a 2226H w/ a 4507 box, you might look for that one for some published measurements.
 

Attachments

  • 3jbl4507.txt
    987 bytes · Views: 65
Last edited:
Hi screamersusa,

Post #11: "...4ea. 6"Dia. x 12"long..."

That's a "typo" it should say: 4ea. 4"Dia. x 12"long, and that's basically what I would recommend for the 3015LF in that box, it should be an easy fix, now strange plumbing required.

I took the information from audiokarma and JBL and made you a quick drawing, hope your boxes are similarly sized.

Regards,
 

Attachments

  • JBL_4507_3015LF_Ports.pdf
    34.2 KB · Views: 100
I'm dying with anticipation on the best port size.... thanks guys!!!
Look here,
You are asking for trouble. :D
If you look at my post your question was already answered (post#3).
Then, if you keep asking (more answers, it might help you or not, and it's fine with me) you will receive the same answers or... different ones that migh take you further away from the solution you need or not.
Let's analyze here the beautiful drawing that is linked in the previous post by tb46. It's fine but have in mind that it's a different alignment. (You don't mention what is the alignment you want, for the record) So because you are using it as a sub I gave you a low (30Hz) tuning.
The above tuning (by tb46) is about 41Hz with those (4x) 4" x 12" ports, if you want that, what you will get below in LF - you can simulate in any software available for free - will be:
F3 41 Hz
F6 35 Hz
F12 28 Hz
F24 20 Hz

Now let's check a different alignment, Eminence KappaLite3015LF with 30Hz tuning and better LF extension (from post#3:
(4x) 3" x 13.6" ports (one constraint is the internal dimensions of the speaker and ports have the JBLs original section/diameter)*
F3 47 Hz
F6 36 Hz
F12 23 Hz
F24 16 Hz

*Or something in between, we don't know.
Besides, you can also vary the tuning 40Hz, 35Hz, 32Hz or lower, there's not one unique solution.
You have to mention several things here.

Power:
http://www.eminence.com/pdf/Kappalite_3015LF.pdf
Driver is 450W (RMS)

Amp is:
Mackie - m1400
1400 watts @ 4 ohms bridged
1000 watts @ 8 ohms bridged

So the closer to 900W would be "1000 watts @ 8 ohms bridged", be careful. ;)

Then, you can make a "new speaker" meaning by this cutting new ports or not. You have to pay attention to that fact, to place a 4" port in the place of a 3".
I would say that the higher tuning is the "boing, boing"- one note sub, but hey, I'm not the judge (it can also result better for parties and the lower tuning being too muffled. Also the lower tuning will relieve the sub of excursion to lower frequencies. Have in mind that the higher tuning (41Hz in this case) gives an excursion of 17mm@30Hz with 900W(RMS) or 78.52 V, close to disaster (look at the Xlim for this driver). You need to be more specific not just leaving the work of guessing for us. I guess there is already enough material for you to think about...
I'm not saying here that everything I'm saying it's right, but for you to pay attention to every little detail, after all, I may be missing something also but you have to understand that reverse engineering is not an easy task and you should be more tankful also and specially when you mention so many constraints. :)

ps: you are in the good track, helped here by various members. I'm out from this thread. Regards.
 
Thanks TB46
Im seriously considering just building two new cabs instead of another 4607. Might be easier than modding the original cab and might be able to adjust a little to fit in the Explorer sport.
Perhaps I could drop all 4 ports to the bottom?. Gonna have to put a grille on it and I hate blocking ports.
That's a better option. Driver needs a larger enclosure after all. Best. :)
 
That's a better option. Driver needs a larger enclosure after all. Best. :)

Thanks inductor... If I could fit my Furysubs in the explorer....I'd simply use them as I have them :)
I'm basically looking to put low kick thump 40-70 under the peaveys for karaoke.
In a cab close to the peavey size that I cab build simply and dont have to time align. If I could I'd buy different drivers to build a hi/fi type karaoke sub I would.
If the wife needs to dj, we'll have to rent a trailer for the furysubs.
Cant sell the 3015lf, cant move the fury's, gotta move the 3015's for now into
something that will do the job. Not gonna run 900w at war volume for kj.
 
OK, what is the max HxWxD o.d. dims you can can live with?

BTW, what are the Kappalite's specs? I just noticed I have several different sets and they're not close enough to just use the mean. The most conservative set dictates at least a 10 ft^3 cab to get down to 40 Hz.

GM
 
Last edited:
Hi Inductor,

In Post #6 you are saying: "...ports are over dimensioned..."

Using 2ea. 3"Dia. x 6.25" long ports: @ 40Hz the port velocity is 21m/sec, and @ 30Hz
36.5 m/sec. What do you consider appropriate port particle velocities for this sub, and PA use? This tuning also looses SPL @ Xmax versus the original tuning, and v. the 4ea. 4"Dia. x 12" long tuning. The 4ea. 4"Dia. x 12" long ports provide to me the clearly superior tuning for the 4507/3015LF combination. A single 8"x12" port would also be a possibility.

I'll attach the Hornresp export file.

Regards,
 

Attachments

  • 4jbl4507.txt
    974 bytes · Views: 46
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.