Not really a ton of Xmax from this 12", but $180.
Lots of BL, Fs of 54Hz may be okay for a 40hz tapped horn.
B&C 12FW76 12" Professional Woofer 8 Ohm | 294-5951
Lots of BL, Fs of 54Hz may be okay for a 40hz tapped horn.
B&C 12FW76 12" Professional Woofer 8 Ohm | 294-5951
Ooooh Art, I was about to personally challenge you to a death match over this point. But I decided it might be wise to do a bit of research before I embarrass myself.
The phase shift idea I was first exposed to by a nationally known acoustics engineer/recording studio designer back in the 1980's. It reinforced my previous experiences designing home stereo speakers and PA tops, as the flatter I could get the frequency response straight out of the box, the better they sounded to me.
The best evidence I could find to support your position was "myth 6" of this: Exposing Equalizer Mythology
I am not totally convinced either way. There is a big difference in striving for a "pure" sound in a recording studio versus a PA based dance party in a gymnasium with horrible acoustics. Since you used the terms "generally" and "almost always" in your comments, I guess both of us will live to see another day.
To me, this is a personal preference. You seem to be doing this on a professional level, and you probably have assistant with dolly's to do the grunt work. For me, if I have to life something over 50 lbs., my old heart get beating pretty rapidly.
It seems I may be the only one interested in comparing these various Lab12 designs, but I would like to see this post function like a product test to give designers feedback on what people like/dislike about their designs. Personally, I hope to use it to gain design knowledge for myself.
3)Better to have it and not use it, than to not have it and (have your kids and grand kids) miss it.
Very good point. But that is also a personal point - someone may prefer a slight SPL boost over a low frequency extension. But I think I will take your advice though for what ever I end up building. Thanks.
That is another personal preference. I have a fair amount of money but am pretty frugal. But some young guy, making minimum wage, would have to work about a week to buy a Lab12.
You are right again. But the benefit of the Lab12's long illustrious life is that there are many subwoofers built with it to compare.
I probably won't either, but Amazon sells them for $140-$150 every few months, and they are still a very capable driver.
Hey spenserh, welcome. It sound like you are pretty experienced for a lurker. Don't worry about making stupid comments here, that is my job!
That was your cabinet huh? Wow, nice job. It is great that this was the post that got you to start posting here. It is also interesting that you mentioned the BFM T30. That is another cab I found when I was researching Lab12 designs. That may be a future contender if the post continues. It would be GREAT to hear you input on the difference between these two designs.
Those were some great comments you made on your real-life experiences with the Dual Lab12 BR cabs. What made you choose to build these particular cabs over others? Are there any other comments you care make about this design and how it has worked out for you? Thanks
B&C 15TBW100, B&C 18TBW100.
But this thread imposed a Lab 12 PA handicap, so they are not allowed
.
Let's see-, 10% of your music could use a 1/6th octave extension that no one will notice (except you, if you happen to be comparing it with some GK Ultraphones or a computer), but it costs you double the truck and storage space, driver and amp count.
Most would not find that "worth it".
It took me a while to make the decision that a 35 Hz TH was "good enough" for portable PA use, but in 40 years have never been more happy with any cabinet in terms of output, size and cost per performance.
The top cabinets I use weigh 50 pounds, that is about as much as I feel comfortable lifting over my head, though I wheel 5 of those in and out of a 5x8 trailer in one trip.
I generally do all the two wheel dolly work on the PA cabinets I use presently, the rest of the system is on wheels and stagehands (God willing..) push that in.
At any rate, when you grow up with top cabinets weighing as much as 440 pounds, 150 pound subs (which are seldom lifted) seem like patio furniture to move, even for a 1956 model 150 pound guy
.Thanks for the kind welcome
My biggest issue with the Tuba subs are that they don't meet the hype. It sounded good, got (fairly) loud for it's size, but it didn't best a single 18 BR as claimed by the designer, and it was a tough build for a beginner, after firing up the first one I wasn't inclined to invest the effort to build more.
Art's Dual Lab 12 sounds good, and the build is straightforward, it's limited by it's efficiency and power rating which is relatively low by modern standards. Again, it didn't best the mentioned single 18 reflex in max spl, but it sounded noticeably "nicer" - nice enough that a lampie complimented them without being questioned.
I think you probably hit the nail on the head Art, the extra extension would be nothing more than an ego boost!
Random observations:
1) About 13 years ago on the basslist there was some talk of doing a version of the Lab12 with XBL, but nothing ever came about though. (IIRC, the Adire Audio Shiva, Tempest, and Lab12 were/are made by Eminence.)
2) If you like the benefits of XBL, the Alpine Type R and Type S drivers offering something similar. Basically a flat BL curve.
Here's a comparison of four of these drivers:
driver: Eminence Lab12 / Alpine SWR-12D2 / Alpine SWS-15D4
voice coil diam: 2.5" / 2.6" / 2.6"
power handling (rms): 400 / 1000 / 500
xmax: 13mm / 20mm / 15mm
displacement: 0.65871 liters / 0.958 liters / 1.1685 liters
FS: 22hz / 31hz / 27hz
data is from here:
Eminence LAB 12 Professional 12" Subwoofer Speaker | 290-570
http://support.alpine-usa.com/products/documents/OM_SWR-10D2_4_12D2_4.pdf
http://support.alpine-usa.com/products/documents/OM_SWS-101215_D4_2.pdf
IMHO, those Alpines are tough to beat. Even at $200-$300 each, they offer features that the Lab12 doesn't have. A flat BL curve and higher displacement. The higher FS is very useful for a tapped horn, as the bandwidth of a TH is highly influenced by the FS of the driver. Basically a driver with an FS of 22hz tends to work well in a sub-20hz TH, and that's often more sub-bass than you need for music.
The kicker is that the Alpines are dirt cheap. If someone can show me an underhung woofer with over a liter of displacement for under $130 delivered, I'm all ears. I know there are some drivers that offer more displacement for the money, but none have a BL curve like these drivers do.
Here's the prices:
Lab12 : $175 delivered
SWR-12D2 : $162 delivered
SWS-15D4 : $129 delivered(!)
An externally hosted image should be here but it was not working when we last tested it.
The flat BL curve implies that there's some type of split gap motor, similar to XBL.
Alpine has a patent on it. (www.google.com/patents/US6639993)
Generally these types of motors sacrifice maximum BL for flatter BL over the curve... Basically the parameters of a conventional loudspeaker change at high excursion. These don't, or at least not as much.
TLDR: the distortion on the Alpine is likely lower than the LAB12. But you'd have to measure them in an identical box to be sure.
Alpine is using Klippel.
I know that car audio subwoofer specs are often completely full of BS, but these Alpines seem to be an exception. (The RMS power handling seems exaggerated on the Type Rs, which is why I included the voice coil diameter in the comparison.) As far as efficiency goes, the LAB12 is hardly efficient. In fact, that was one of the things that was so unique about the sub. When Danley published the design most horn subs used low xmax drivers with high efficiency. Danley went for a high xmax driver with low efficiency, because maximum output is generally set by displacement, not by power handling. Especially for subs.
The Type Rs have a beastly 70mm of xmech. I am literally listening to a Type R tapped horn as I type this, and it's possibly the cleanest sub I've ever owned. Honestly my only complaint is that it's SO clean, sometimes the lack of distortion makes it sound a little too 'polite.' But it can certainly take some abuse.
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I use the Type Rs in my car - see my review here: Alpine Type R 12D2 - Car Audio | DiyMobileAudio.com | Car Stereo Forum
Measured distortion was 7~10dB less at lower frequencies than my previous subwoofers (which weren't bad drivers either). And yes, they can move some serious air.
Measured distortion was 7~10dB less at lower frequencies than my previous subwoofers (which weren't bad drivers either). And yes, they can move some serious air.
Yeah I actually kinda feel bad for Alpine. If you look at patents.google.com* they're investing a lot of time and effort advancing the state of the art. Lots of great technology in the Type R and Type S drivers, and this is particularly unusual in the world of car audio, where style often trumps substance.
If you read the reviews some have complained that they don't get loud enough.
But I think the *real* problem is that ultra-low distortion and high power handling subs just *sound* different. You get so used to hearing the distortion, when it's gone it sounds like the sub is doing something wrong
* here's the patent for increased power in the Type R : https://www.google.com/patents/US7634101
Brian,
You mentioned that the tests were not near Xmax, (and probably not near full power either) it would be interesting to see what the distortion levels are at both.
I have tested distortion of the Lab 12 in sealed, ported and tapped horns, would be interesting to compare the Type R.
Just from looking at the patent for increased power in the Type R I'd expect power compression to be far less than the Lab 12.
It would be difficult to do that in-car, as at those levels panel flex and other things would have contributed significantly to the distortion measurements. But my listening tests suggest that distortion from the 12D2 remains pretty low even at higher levels, levels at which my previous drivers were screaming for mercy, LOL.
^^^ This pic says a lot. You can see the Alpine's 70mm of xmech is no joke. I see a lot of car audio drivers where they slap a huge surround on a woofer to give the impression that it has a lot of xmax, but then you flip it over and the woofer is 5" deep. The Alpine Type R eights are nearly as deep as they are wide.