Just a curious question...

[needtubes]

I have been on the hunt for exactly what I am looking for in a sub (which is proving impossible to find). Anyway, I stumbled upon the JL Audio 13W7, which is huge, has huge Xmax, can work in very small sealed and PR boxes and put out quite high SPL doing it. In fact, it appears to best my Blueprint 1503 in all respects at first glance.

So, I was just wondering... Why doesn't anyone else use or talk about this beast? A search of the forums returned only about four threads. I know it is expensive, but if you look around, you can find them for $600 brand new on eBay. I know they probbaly have enormous inductance (so, I would be getting nowhere in my case going from Blueprint 1503 to this), but otherwise, the specs look pretty good. I, personally, would almost rather buy one of thes than a new Tumult.

So, I was just wondering what others' thoughts were about this driver. It seems as though it could be promising...

[Stocker]

Mostly folks around here tend to use home audio speakers in the house, car audio speakers in the car, and mostly they talk about home audio; this is a car sub.

That said, with a properly designed box (usually way bigger than for the same driver in a car), a good car sub can do well at home.

[95Honda]

Just alot of better subs out there for $600, I think that is the only reason. I used a 13W7 in the home stereo for a long time, I loved it, it sounded great. JL did a phenomenol job designing the W7 series, but they are overpriced. When I was offered more than I payed for my W7, it was out the door and I upgraded.

[needtubes]

95Honda-

Just wondering... What did you upgrade to?

I like the allure of an impressive-looking driver and am having conflicting ideas about my sub design between one impressive woofer or two or more "lesser" woofers...

[95Honda]

I tried an Adire Maelstrom after that, sold it because it would reach it's mechanical limits very easily, had a Brahma 15" sub for a while, got rid of that, it was nice, but didn't have enough output by itself, a Pair of Type-R 15s (blah), a pair of Tumults (sounded awsome, but I blew 3 of these in 2 years, my fault), and now a pair of modified XXX 18s..... I like the XXXs...

[nunayafb]

...exactly what I am looking for in a sub...

could you elaborate on this please, Im curious what specifically you are looking for?

regarding the 13w7, what are you looking for ht subbass, music range bass ~40hz cutoff or loudness? Also with only 3ohms wired in series (DVC) you might have trouble finding an amp that can drive it safely. If I was in the position to spend that much money on one sub it would be a tumult 18D2, but im not.

Anyways just my two cents

[needtubes]

could you elaborate on this please, Im curious what specifically you are looking for?

They say that what I am looking for is impossible because of physics... Which, I must agree to, really...

I want a small-to-mid sized box (less than 4 cubic feet) that has extremely low distortion, high SPL (at least 115dB sustained from 30Hz up) all the way to 20Hz (-10dB max at 20Hz anechoic, preferably no more than -5dB at 30Hz), has all the slam one wishes for HT (which my current sub does, but it is just too large), but plays ultra musically for classical music/soundtracks (my current sub is 'ok' here). Also, for occasional rock music, I need clean, distinct control so the quick kick drum beats are clean and clear (not exactly a strong suit of my current sub).

I think I can achieve most of this by using a PR sub. If I use two PR's with very high mass (thinking 1800 grams, which is nearly 5 pounds, IIRC) in a relatively small box (2.5-3.5 cu.ft.) with a suitably low-distortion, extremely high excursion sub driver, it should all work pretty well. The way I figure it, for classical music, the excursion will not be very long (except for low bassoon/string bass/tuba/etc. notes), so the cleanliness and detail should be there because the PR's won't lend much delay to the system because they will weigh too much to move unless the sub driver is really pushing some air. Maybe I am imagining this, though. Anyway, in theory, it also seems as though it will retain all of its depth and slam since I'll be able to dig deep while retaining good SPL down low.

I am just searching for that suitable, low-distortion, high-X-max driver. My current driver (Blueprint 1503, which has 26mm X-max) seems like it will work, but I don't have a lot of faith in it because of its supposed high inductance, which undoubtedly will affect the sound in the much smaller box that is tuned higher. Currently, in its 7 cu.ft enclosure tuned to 15-18 Hz (I forget which, really) it sounds quite clean, although still muddy on top with rock music, and a little too boomy/over exaggerated for classical music soundtracks. But, it has immense slam and goes really deep, making movie experiences amazing.

I bought a Behringer Feedback Destroyer, but I haven't had time to analyze my room yet (if I ever do get to it at all...). So, that is what I am looking for. In short, servo-performance for music, huge-sub performance for HT, all from one relatively small PR box. And, to top it off, I don't want to spend a lot (I could, but for some reason, I just have this feeling that subs should be cheaper and I feel cheated when I have to pay $600 for a driver, even a cool looking one).

[nunayafb]

It sounds like you and I are in the same position except for spl, dont care about going that loud.
To help select a good woofer, what size room do you have? what are the mains and how low do they go cleanly?

...because they will weigh too much to move unless the sub driver is really pushing some air.

If they move at high volume or low frequencies, they will also move at low volume and high frequencies. Dont know much about PR but ive read others mention problems with too much mass.
Have you considered an LT ciricuit?
Personally I would stay with sealed, if you dont mind the clamshell look (you can cover it with grill cloth)I would go two subs isobaric. This configuration halves the box size requirement, and having two drivers mechanically out of phase "cancels" non-linearities in the suspension and motor.

[95Honda]

A few points of my opinion I would like to add-

Passive Radiators only add cost over a properly sized vented design, nothing else (assuming space is less of a concern than efficency).

A vented box will give you more output and less distortion than a sealed box. (Again, assuming space is not a concern)

An LT is an inefficent design that should only be used because of space constraints.

Use a larger or multiple woofer if at all possible and cut your excursion down.

Isobaric adds 2X the driver cost and not much else, unless you are primarily concered about size, again.... There isn't a whole lot of audible distortion that occurs because of suspention non-linearities in the drivers currently avalible.

For a subwoofer, displacement is king for bottom octave performance. Don't expect much from little woofers with average throw.....

[nunayafb]

A vented box will give you more output and less distortion than a sealed box

Yes, but not below resonance, if you tune ported boxes too low you get low frequencies but the rest of the bass isnt quite as good. If you tune it optimally, you get clean bass like you mentioned however you sacrifice the really deep "HT" bass. With classical music that he listens to, like me, I would prefer low group delay so that the sub integrates with the mains better and sounds more coherent. I know there is not alot of data (maybe now there is) on audibility of group delay at those low frequencies but I have always prefered sealed anyway.

Use a larger or multiple woofer if at all possible and cut your excursion down.

this would be nice but he has that, he wants smaller. Larger woofers usually need larger boxes. Multiple woofers... double up on woofers double box size. You are right, that is the best way but hes not looking for that. Im going to be reworking an 18" with a bad foam surround, I have room for it and am ok with a fairly large box. This is why I asked him how big his listening area is, you can get away with smaller cones in smaller rooms.

Isobaric adds 2X the driver cost and not much else

unless

you are primarily concered about size

or

audible distortion

You said there is not alot of audible distortion, it would be nice to get rid of what there is, right?
ALL suspensions and motors have some degree of non-linearities, it doesnt hurt to minimize it especially when you can halve your box size in the process. with isobaric you can run two 18's or 15's and maintain compactness, low excrusion and high spl.

Sorry to be so combative but Im trying to focus on what he wants not what you and I consider to be acoustically best. Im sure he know bigger is better, and large boxes are better for low bass, he has one!


Btw needtubes I modeled the 1503 in winisd, no wonder you dont like the musicality of it. The woofer rolls off really early, and the 16-18hz tuning with that box size produced a roller coaster FR and lots of group delay. Unless the new 1503's have different specs from yours, that would explain the muddiness.