Sub1500 Enclosures

[JuniorJBL]

OK so many have had their 1500's for some time now and have built a cab or two.

What I would like to know is:

What size do you prefer?

I have used a 2.0 cu ft and a 3.0 cu ft. sealed boxes. I was finding that the 2.0 box sounded a tad better than the bigger box.

I would really like to hear from the ported box owners as well.

I was thinking of building a pair of dual 1500 cabs and would like to find the best design for this setup.

[MJC]

I've tried a 2.5 and a 4.0. I wouldn't tell any difference, so I use the 2.5 to save space.
Both sizes were actually the same box. The construction was two layers of 5/8" mdf, with all edges "stepped", creating rabbits. So all sides interlocked with each other.
To convert the 2.5 to 4.0 I built a four sided 8" extention. I just had to remove the back, that was held in place with thru bolts, add the extention, a bit more insulation, and then bolt the back to the extention.

Both sizes are sealed, I prefer the better transient response of a sealed box.

[Mr. Widget]

This has been discussed quite a bit. I am currently using both sealed and vented for a music system and for HT respectively.

Love them in both applications.


Widget

[maxwedge]

I like 'um sealed and mine is 5 cu ft for two.:bouncy:

[reconed]

I am in the process of making my first subwoofer project. I'm using the sub1500 in a 1.8 cu ft sealed box with electronic EQ. I chose the small 1.8 cu ft box because I don't have the space for larger units, and the sub1500 was specifically designed for small sealed enclosures. I plan to install a pair of these for use mostly for HT. I have the first box glued together, and I hope to test the first unit before the end of this week. I'll let you know how it sounds.

[sfogg]

I have L/R subs with a pair of Sub1500s in each sub. The cabinets are 6ft^3 sealed designs. In room they are basically flat to at least 10hz. TrueRTA doesn't go below 10hz so I don't really know where they roll off. Probably at 7hz which is where the high pass filter in the K2 that drives them is. Room gain is wonderful. ;)

Shawn

[JuniorJBL]

This has been discussed quite a bit. I am currently using both sealed and vented for a music system and for HT respectively.

Love them in both applications.


Widget

OK
After a long search I did find what you said about yours.
Sorry I did not search before but that thread is VERY long on top of reading other threads.

http://www.audioheritage.org/vbulletin/showpost.php?p=70528&postcount=452
;)

[Tom Loizeaux]

I am about to begin building a cabinet for my JBL Sub 1500 (at last!).
I've read most of the posts on this subject and still aren't sure I'm doing this correctly.
I plan on building a 2.5-3 cu.ft. sealed box and use the PE 250 watt plate amp with the 30Hz 6dB boost (#300-796). I expect to dial in just the right phase and just enough level to hear the low end fortify. I am going to use this with my 4343s running full range, so the sub with be adding VLF to the 4343s. I don't expect I'll need much level - but just enough to build the 30 to 50Hz area.
I've been listening to my JBL PB12 used this way and it sounds very nice.

Am I making the cabinet the right size, should I be making it sealed, and is the 250 watt plate amp enough power for my application?

Thanks,

Tom

[Mr. Widget]

Sounds perfect to me. The 250 watt amp should do the trick unless you have a large room or use the 4343s for playback at pretty high SPLs.

Does your Sub1500 have the dreaded orange glue?


Widget

[Tom Loizeaux]

...Does your Sub1500 have the dreaded orange glue?

Widget

Widget, I'm not sure! I've been looking at it. The glue between the spyder and the cone is clear, with tiny bubbles, but it's hard to tell about the glue on the outer edge because the spyder is an orange color and the glue makes it look dark...or wet. Serial # J864-05750 oval sticker 81H d JBD-1
("d" in red pen)
What do you think?

Tom

[Mr. Widget]

I'm not sure either... but it sounds like you are probably OK... I doubt that very many were improperly glued. We have heard of only a handful of failures.


Widget

[MJC]

I plan on building a 2.5-3 cu.ft. sealed box and use the PE 250 watt plate amp with the 30Hz 6dB boost (#300-796). I've been listening to my JBL PB12 used this way and it sounds very nice.

Am I making the cabinet the right size, should I be making it sealed, and is the 250 watt plate amp enough power for my application?

Thanks,

Tom
In comparing the PB12(which I have) to the sub1500, remember that the PB12 is ported and 8 ohm, and you're building a sealed sub1500, which is only 4 ohm. All that makes the PB12 much more efficient. The sub1500 is rated at 800w I don't think that 250w is enough.
I'm using a Crown K2 amp(800wpc) to power two sealed, 2.5cuft sub1500s in a room that is over 3100cuft, if I have the pocket doors closed going to the dining room. If the doors in that 8'8"x7'0" elliptical archway are open, then it is more like 5500cuft.
In that same room, I also have both L/R L212s connected to two B212 subs, and run them full range.

[Tom Loizeaux]

... remember that the PB12 is ported and 8 ohm, and you're building a sealed sub1500, which is only 4 ohm. All that makes the PB12 much more efficient. ...


Thanks for the post.

With the Sub1500 being 4 ohms, it will draw twice the power from the amp then an 8 ohm driver would. Also, I run the PB12 volume control at about "11:30" - whatever that means in terms of the power I'm using?

I want a plate amp for the Sub1500 and the variable phase, speaker level ins and mono summing are a good thing. What are my other choices?

Tom

[MJC]

Also, I run the PB12 volume control at about "11:30" - whatever that means in terms of the power I'm using?
I'm not sure about that, as I'm not currently using my PB12, at this time.


I want a plate amp for the Sub1500 and the variable phase, speaker level ins and mono summing are a good thing. What are my other choices?

Well, if you must use a plate amp, I prefer using a K2 stereo amp, then Parts Express has a 500w plate.http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=300-806