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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => SR Forum Archives => LAB Subwoofer FUD Forum Archive => Topic started by: Antone Atmarama Bajor on December 29, 2006, 08:12:26 AM

Title: Can you find better.
Post by: Antone Atmarama Bajor on December 29, 2006, 08:12:26 AM
     I possed a challange a long time ago, and no one who tried to step up seemed to fully understand the criteria.

    Can anyone find any driver that bests the

lab12 as a general purpose subwoofer, subwoofer anywhere close to the same price range.

    I think it really takes the ability to model or measure other drivers against it to make these determinations.  As far as I found, the LAB 12 is still the best bang for the buck.

It seems some of the Higher XMAX much more expensive alternatives often seem to make mechanical noise well before over excurion is reached which to me makes them much less useful, and certainly not worth the added cost.

    I guess I will expand the criteria to can anyone find a single 18 that can get the same performance as 4 Lab 12 drivers in the same price range (As they are about the same SD and VAS).

    I dare you, tripple dog dare you to even.

Thanks for specing this kick ass driver Tom!!!

Antone-

   
Title: Re: Can you find better.
Post by: leon douven on December 29, 2006, 02:25:07 PM
this one??
acoupower 18"
the site seems offline

Best regards
Leon

1) High power handling. 2,000 to 3,600W RMS, depending on the application. 2) Flat response. Both drivers are flat +-1dB to 500 Hz. Not typical of high power subs... but that way by design. This extend response allows the drivers to be used with a wide array of crossover frequencies and slopes.
3) Very low power compression. Inaudible for most applications.
4) Super linearity. 100% linear BL product for +18mm of travel in EACH direction. Proprietary spider and precise details in the surround provide exceptional mechanical linearity and smooth overdrive characteristics.
5) Extremely low distortion, below the threshold of audibility for most of the output envelope.
6) We are experts in Acoustic Power Density. These drivers have the highest low frequency output ever obtained in standard 15" and 18" sizes thanks to 78mm of travel, high power handling and low power compression. In many applications, one driver can be used where two are being used now.
7) Relatively simple and bullet proof design. We believe in the KISS principle.
Parameters optimized for very low frequency performance. These drivers can still be used to generate ludicrous amounts of "standard" bass (50-100 Hz) if needed, but they have been designed to excel at very low frequencies, requiring little or no equalization for many properly designed subwoofer applications, maximizing the power available from amplifiers.

18"
Sd = 0.108 m^2
Cms = 106.6 um/N
Vas = 174 liters
Re = 6.2 ohms
Mms = 305 g See Below
Fo = 28.2 Hz
BL = 23.3 t*m See Below
Qe = 0.62
Qm = 8.90
Qt = 0.58
SPL = 90.5 See Below

The data above is derived from the impedance curves. Note that the Mms values above includes ALL of the acoustic mass as well, which is substantial in subwoofers. In addition, the actual BL values for these drivers is about 8% higher than the parameters above. As a result of both of these measurement artifacts, the calculated SPL 1W/1m dB's are lower than actual SPL's by 0.5 to 1.5dB. We have provided the actual SPL's in the data above.

Overall Diameter = 462mm
Mounting Holes = ( 6.4mm holes on a 441mm B.C.D.
Cut Out = 425mm ; Maximum thickness of baffle at cut out = 1.25" (32mm)
Weight = approximately 44 Lbs.
Depths assuming "drop in" or "standard" mounting:
Mounting surface to back of driver = 224.50mm
Mounting surface to top of surround roll, full excursion = 48mm
Diameter for the depth above = 345mm nominal. Suggest you use 355mm to account for the cumulative errors associated with cabinet and grill errors... depending on the application
Title: Re: Can you find better.
Post by: Antone Atmarama Bajor on December 29, 2006, 04:42:56 PM
     Yes a very nice driver, by a fantastic engineer.  But again you missed the point.  IS IT ANYWHERE NEAR THE SAME PRICE RANGE OF 4 LAB 12's??????

    There is also the added convieninence factor that one has the option to not build one ludicrously large cab when using the 4 12's.

Antone-
Title: Re: Can you find better.
Post by: Mark "Bass Pig" Weiss on January 01, 2007, 10:57:12 PM
Bassmaxx ZR18 would be my choice. More efficient than the AccouPower, and less expensive. And, a muc stronger cone, if you order it with the fiberglass/Kevlar cones. I don't consider a paper-coned driver to be a real woofer. Smile
Title: Re: Can you find better.
Post by: Antone Atmarama Bajor on January 02, 2007, 02:07:19 PM
     The Cones in the Basstech 7 are paper (pulp)  with some sort of EPOXY like resin holding them together.  They survive greater than 3:1 compression ratio loading.

    I believe the Lab 12's are some sort of epoxy impregnated paper.  I don't think radial or concentric fatigue is a common failure for Lab 12's.  There's nothing any less subwoofer worthy about them than Kevlar cone drivers.

    Again what is the Retail cost of the Bassmaxx drivers 1 18vs 4 Lab 12's?.

    The Adire Tumult 18 looks pretty damn cool too but an optimal vented enclosure for one of them makes an awfuly un-weildy box.

    For a little more cost than 4 Lab 12's you get a bit more extension and about the same sensitivity.  But Less Configurable.

    And Remember that a drivers sensitivity figures seldom has anything to do with its SPL performance below 80Hz.

Antone-

P.S. I have a sneaky suspicion that the AccouPower Drivers are inherently Better Sub Bass Transducers than any of the motors based off of the Aura/Seismic NRT designs.  They seem to be really monsters down to about 40Hz.  But don't seem to have a very linear response curve if you try and extend them down much lower.  Someone here mention something about Drivers with a really high BL tend to be better suited for Midbass/Bass.  I would be interested in hearing an elaboration.



 
Title: Re: Can you find better.
Post by: Tim Duffin on January 04, 2007, 12:19:49 AM
hardly any companies can make a speaker cheaper than eminence.  I think that is the reason for the low price.  Although I suspect that a jbl 2258 might be better than those 4 drivers.  

T
Title: Re: Can you find better.
Post by: Antone Atmarama Bajor on January 04, 2007, 09:28:35 PM
      Well this is what Harris Tech shows.

JBL Red
Lab 12 Orange

index.php/fa/7227/0/

    I did the prediction at 800 Watts as that is the JBL's RMS Rating.  The Labs would be a total of 1600.

   The JBL is obviously the Lord of all above 50Hz.  But not bellow.

   The 4 Lab12's also require ~4x the volume.

   I have done realworld half space measures of the 4 Lab12's in a vented Box VS.  A single JBL 2245, A pair of TAD 1603's and a Pair Of JBL 2225's.  The Labs were the kings of the deep in all cases.

   Eminence formerly Magnum 12's (Definimax) are much more expensive than the Lab 12's.  I'm not sure if you intended to imply that they make cheap speakers or they can make speakers cheaper than their competitors?  

Antone-

Title: Re: Can you find better.
Post by: Antone Atmarama Bajor on January 04, 2007, 09:54:17 PM
Just for fun here is the same graph with the Seismic Driver (I don't have TS params for the CGN) In two cabs.

    Yellow is Harris tech Recommended, Green is ~same vb as 4 lab12s

    Now about the same extension of the Lab 12's but 1 driver in 1 giant box.

index.php/fa/7228/0/

Very close, Xmax gets a little High I'm not sure what type of mechanical noise or THD starts happening with the Increased excursion, and those seismic certainly have a large reserve of that well beyond thermal limits.

    If the seismic cost is close to the same its a reasonable option but the 4 Labs still have 2 X RMS Power handling, and can be put into two or 4 smaller boxes making transport easier.

Antone-  
Title: Re: Can you find better.
Post by: leon douven on January 05, 2007, 12:34:11 PM
Hi Antone,

what about the acoupower 18 ?
ok ok these are expensive... but I'mm getting curious
how these would look in a graph

regards

leon
Title: acoupower cabs modeled.
Post by: Antone Atmarama Bajor on January 05, 2007, 07:51:16 PM
Well I don't have Le so don't expect the HF response to be so great.

Here are the graphs, I set max power at LAB 12's power limits 1600Watts RMS.  I'm actually surprised with the results.  Granted the Acoupower probably behaves a little better at high excursions.

    The accoupower has a vb of ~ 13cu' the port displacement makes it more like 17.6cu'.

    The Lab 12 has a vb of ~12cu' port displacement puts it up to 13cu'.

index.php/fa/7234/0/

Red=Acupower Orange=Lab12

I'm actually surprised with the predicted response.  And who makes an amp that delivers 3600watts?

I know the box and porting gets crazy because of the huge xmax of the driver.

    Again More expensive and less configurable for ~ the same performance in a larger package.

Antone-

Title: Re: Can you find better.
Post by: leon douven on January 06, 2007, 08:07:46 AM
Hi Antone,
looks verry good...
3600watts, Crown I-tech series... no prob.
regards
L.
Title: Re: Can you find better.
Post by: Mark "Bass Pig" Weiss on January 06, 2007, 09:23:18 PM
I did say they were Kevlar-impregnated fiberglass, not Kevlar alone--huge difference. My EVX180Bs have Kevlar cones are are pretty rigid, but the Bassmaxx cones are like the hull of a boat in terms of stiffness. I can't stress enough, the point that it's the cleanest driver I've ever tested. Its THD performance is more akin to high end amplifier ratings than woofer ratings.

I know that the paper cone version of CGN's 1808 goes for $695. But that's not a Bassmaxx ZR18. I'm sure the Bassmaxx are a bit more, due to the Kevlar-impregnated fiberglass cones and custom suspension components. Also, the motor is a bit different, with a longer pole piece. Since I bought mine as demo models (prototypes, actually), I don't know what the same configuration would cost as new.

I too considered the Tumult, but was offput by the low efficiency, same as with the Acoupower driver. Although the latter LOOKS impressive, with it's huge heatsink around the magnet assembly.

To my knowlege, the Bassmaxx SPL sensitivity rating is in the bass range. It's sensitivity at 30Hz and below is higher than any other driver that I have auditioned. And the only driver I've tested that's totally free of audible THD. As a result, the room makes more audible noise than the driver, when the test frequency is below 20Hz.

Resonant Technologies makes a driver with a 54mm Xmax, but the sensitivity is so low that you'd need 6,000W of power into it to get what I get with 1500 into the Bassmaxx driver. And my cabinets were not designed expressly for the Bassmaxx. They were designed around a pair of Altec 3184s in 1982. I'm currently drafting a design for a much more suitable cabinet, with a port area that is equal to the sum of all the cones' area, for increased room coupling of port output. I'm going to be building a scaled-down convertable prototype with 6" drivers for testing the old and new designs via realworld response measurements.

It should be interesting to see what sort of gains can be achieved with a vent over 700 sq in over a long enough path to achieve the same tuning I get with a 96 sq in vent of shorter length.

Title: Re: Can you find better.
Post by: Antone Atmarama Bajor on January 07, 2007, 05:22:47 PM
If you have the TS params of the CGN I'd love to model it.

    I so far seem to remember the Adire Tumult 18 Having the Best looking predicted Response down to ~16Hz in a vented Box.  But!!! That box needs to be at least 20cu'

    It looked even better to me than the graph of the, Acoupower even though I can't speak for the linearity VS xmax statement that Acoupower makes Vs any other driver.

    Acoupower claims Totally linear BL up to 18mm excursion but it has a 40something mm Xmax!?

Antone-

   
Title: Re: Can you find better.
Post by: Mark "Bass Pig" Weiss on January 10, 2007, 04:22:55 AM
The numbers from both manufacturers are somewhat confusing, in that there is "totally linear" and "Xmax" and seem to be treated as two different things.

CGN has their T/S parameters on their web site, but I have not gotten the T/S parameters on the Bassmaxx drivers. That's one thing I have to bother David Lee about in the coming months, as the project draws near.

My rough estimates call for a box that's about 34 cu ft, including a massive vent. Woofers will be in a slightly smaller enclosure within that big box.

This rendering is my concept of the box.
index.php/fa/7358/0/
Title: Re: Can you find better.
Post by: Tim Padrick on January 11, 2007, 11:29:25 PM
There's also the Worx Audio driver: http://www.worxaudio.com/product_desc_true.php?id=56
Title: Re: Can you find better.
Post by: Antone Atmarama Bajor on January 12, 2007, 12:43:41 AM
No TS parameters, no price!?

    Could have an 24"  Xmax for all I care, I can't model it, its of no use, except that the basket is shiny and read.  I do like a nice red speaker basket.

Antone-
Title: Re: Can you find better.
Post by: Tim Duffin on January 12, 2007, 01:43:00 PM
If you are bored- could you model 4 JL audio 12w3v2 drivers against the 4 lab drivers?  I know for a fact they have more xmax and power handling, but don't know what they would model.


T
Title: Re: Can you find better.
Post by: Antone Atmarama Bajor on January 12, 2007, 06:10:56 PM
     I'm going by what Bass box has for TS parameters (I had to calculate many of them).

    It claims a slightly shorter XMAX 11mm instead of 13mm for the Lab.

    The Power handling is 150watts per coil so 300watts, 100Less than the Labs.  I went with the 4ohm coil version though I could have done the 6 Ohm I suppose.

Here are the results:

JL audio red, Eminence Orange

index.php/fa/7403/0/

    Close but a slightly larger cabinet for a little less output.  Though the Lab cab is slightly lower impendance.  But this is comparing watt for watt, so it should be fairly accurate.

    HT Bass box normally has accurate default TS parameters.  But perhaps there was an error you can see what was used.  Whats the cost per driver??

Antone-





Title: Re: Can you find better.
Post by: Mark "Bass Pig" Weiss on January 12, 2007, 11:30:16 PM
Antone Atmarama Bajor wrote on Fri, 12 January 2007 00:43

No TS parameters, no price!?

    Could have an 24"  Xmax for all I care, I can't model it, its of no use, except that the basket is shiny and read.  I do like a nice red speaker basket.

Antone-



I'm in the process of trying to track down that information, as I'll be needing it this spring when I built the new cabinets. I'm not sure if the price is available, unless David is willing to sell the raw drivers. I got my four because he was in the process of moving to another cycle of drivers for testing. Definately a fortuitous opportunity, but as such, perhaps not easily repeatable?
Title: Re: Can you find better.
Post by: Peter Wing on January 13, 2007, 08:31:42 PM
Here is a driver that you could get great cost effectivness from..
This driver has been widely accepted as a great quality item by the DIY audio community.. despite the insane price.

http://www.mach5audio.com/product_info.php?cPath=48&prod ucts_id=38&osCsid=e8481273ddba91880943fd3473852bc0

This driver looks like it has been manufactured by Tc sounds--a well known speaker manufacturer.
http://www.tcsounds.com/

Title: Re: Can you find better.
Post by: Antone Atmarama Bajor on January 13, 2007, 09:00:29 PM
    MJ-18

I don't see anything similar under TC sounds.

    Bass Box pro doesn't exactly jive with the TS parameters provided but It modeled decently.  Good down to 30Hz.  A pair of them would be some competition for the 4 lab 12's as far as output and spl.

    Still not great bellow 30Hz, but the first less expensive contender I've seen that has decent performance.  At a little less than half the price I may have to prototype a pair of these.  It would be a little less volume than 4 of the Lab 12's.

   I wonder about the quality of the basket.  It has to be stamped steel and is the power handling RMS??? or Peak??  Another consideration.

     I'd say the MJ-18 is certainly a great value, I would like to know more about the quality of manufacture.

Antone-
Title: Re: Can you find better.
Post by: Nathan Lehouillier on January 13, 2007, 10:43:21 PM
Hi Antone,


I was looking at the 21w1400 18 sound driver.
I think the box would be bigger but it looks
to have the output capability to surpass equal
#'s per $.


Nate KDS&L
Title: Re: Can you find better.
Post by: Les Webb on January 14, 2007, 12:31:53 AM
Peter Wing wrote on Sun, 14 January 2007 01:31

Here is a driver that you could get great cost effectivness from..
This driver has been widely accepted as a great quality item by the DIY audio community.. despite the insane price.

 http://www.mach5audio.com/product_info.php?cPath=48&prod ucts_id=38&osCsid=e8481273ddba91880943fd3473852bc0




That is a very nice looking driver.  I wonder what shipping to the US is like?  Models well in WinISD for my applications.
Title: Re: Can you find better.
Post by: Antone Atmarama Bajor on January 14, 2007, 03:13:23 PM
      The 18sound is only higher output above 30Hz.

     You could try and make a larger than optimal Box to to a shelved extended bass response BUT!  You run out of Xmax way before the LAB12 driver.  The 4 Lab 12 drivers start to run out of xmax around 1600Watts.  So their usable power bandwidth is ~ the same as their RMS power handling.

    If you are looking above 30Hz its great and fine.  I'm interested in a comparable Sub Bass Driver.

Antone-
Title: Re: Can you find better.
Post by: Tim Duffin on January 14, 2007, 06:13:47 PM
you can get them for about 150 each all day, a little hunting could get them to you for 129 or so.  I think that the power handling is very conservative on the JL, by looking at its construction you could see that it has the capability of 2"+ mechanical xmax.

anywhoo-- thanks, I always wondered what they would model against a good pro audio driver.


T
Title: Re: Can you find better.
Post by: Antone Atmarama Bajor on January 14, 2007, 07:03:38 PM
     I'm not sure why xmech is even a spec other than to say, this is where you will cause physical damage to the driver.  The Lab 12 driver has a .8" (22mm) Xmech or ~1.6" Xmech Peak to peak. But is rated at 13mm Xmax.  I think once you exceed Xmax you are no longer effectively in the magnetic gap, or in a range where the magnetic field is not as stable, and the suspension is not as compliant.

    That is not a range you want the driver to operate in as it is where the driver either bottoms out or tears the spider or surround.

    I guess the best thing about having a Large Xmech is that the driver can survive certain types of abuse a little better before breaking.  I don't think it allows the driver to be able to displace more air.  At least not in desirable relation to the input signal.

    150$ is certainly reasonable.  There is one other driver that I've seen on a DIY sub site that has a error correction coil in the driver for servo correction.  That has similar specs to JL and Lab 12.  I didn't catch the price of the driver though.

JL audio and Mach 5 are the two contenders for the Best Value subwoofer motors award so far.

Antone-





   
Title: Re: Can you find better.
Post by: Mark Seaton on January 14, 2007, 07:35:40 PM
Hey Antone,

Just a little pointer...  Check out both TC's dB-500 and CSS's SD12.  Both drivers are actually reasonably close to the parameters for the LAB12 but are likely all too deep to fit in the LABhorn.  They also both have considerably more linear travel and should work very well in mid-size ported boxes you have been comparing.  The different drivers do have their benefits, but the added motor travel should be welcome in a non-horn loaded box, and actually help a good bit when used in a horn.

Happy modeling...
Title: Re: Can you find better.
Post by: John Schmidt on January 17, 2007, 11:03:52 AM
I haven't seen the T/S parameters yet, but have you looked into the JBL 2269 18" driver with 3.5" peak to peak? It's used in the VT4880A and VT4881ADP subwoofers.

Edit: Ouch!! I just checked the price - $2250 for the raw driver! Makes the 2268H look like a steal at $465...

John
Title: Re: Can you find better.
Post by: Antone Atmarama Bajor on January 17, 2007, 08:38:57 PM
     Thanks for those drivers.

   Both of them look like excellent subwoofers.  At a very competitive price.  I'm wondering about the ruggedness of the stamped basket that TC sounds is using.  Does it ping badly?

   Watt per watt the Lab12 models better than the other 2 by a few DB until about 20Hz for the TC sounds.  But the lab 12 also runs close to xmax at rated power and reaches higher excursion than the other two drivers.

    The TC and the CSS seem to need longer larger ports (2X the length of the LAB's)  This models to significantly reduce vent velocity.  It ends up that similar Vt required for all drivers.

     I never thought to hard about the difficulty's in finding a driver that would meet required parameters, to work properly in the lab horn, and would actually fit within its size constraints.

    I guess the fact that the Driver for the BT7 has no protruding motor structure is the reason why such a slim cabinet was achievable.

    The Sonicraft NRT 12 also looked interesting but a little more expensive, for a little less Power handling, a little less output, but more extension out to 16Hz.

    An Adire tumult 18 looks like fun.

Thanks again!!!

Antone-  
Title: Re: Can you find better.
Post by: sheldon harris on January 20, 2007, 06:08:24 PM
Antone Atmarama Bajor wrote on Fri, 29 December 2006 09:12

     
    I guess I will expand the criteria to can anyone find a single 18 that can get the same performance as 4 Lab 12 drivers in the same price range (As they are about the same SD and VAS).

    I dare you, tripple dog dare you to even.

Thanks for specing this kick ass driver Tom!!!

Antone-

   


the criteria is very hard to beat. especially for 4 lab12 drivers.

there is no way that a single 18" driver can have the same sd as 4 lab12s! example. typical 18" sd is about 180 square inch. typical 12" sd is about 78 square"  lab12 is about 79 or so
x 4 = 316 square inch total for 4 labs. vs. at best 180 sd for a single 18" thats an unfair advantage in favour of the labs.
unless i am understanding your post incorrectly.
my contender is the evx 1800   http://archives.telex.com/archives/EV/Speakers/EDS/EVX-1800% 20EDS.pdf
Title: Re: Can you find better.
Post by: Nathan Lehouillier on January 21, 2007, 02:00:55 PM
Hi Sheldon,


I mentioned this driver in an earlier post.
The major problem is it is discontinued.
I would be interested in finding these
drivers if you know were to get them.
I would think they were fairly expensive
in their day.

Nate KDS&L
Title: Re: Can you find better.
Post by: Antone Atmarama Bajor on January 21, 2007, 03:56:21 PM
     Oh if I said Sd, I was confused I really meant Vas, Vas I belive is more important than Sd when it comes to air displacement.

  4 12" drivers have about the same Vas as 1-18" driver.

    The EV looks like a fine driver down to about 30Hz in "clasic flat".  It does really well in a shelved box about the same Vt as 4 Lab 12's also.  Infact models almost the same SPL around 20Hz.  The Labs have 2X the power handling.  Certainly a great driver though.  To bad EV ditched it.  Its a much better sub driver than the JBL 2245 was.

Antone-
Title: Re: Can you find better.
Post by: sheldon harris on January 21, 2007, 06:15:10 PM
Nathan Lehouillier wrote on Sun, 21 January 2007 15:00

Hi Sheldon,


I mentioned this driver in an earlier post.
The major problem is it is discontinued.
I would be interested in finding these
drivers if you know were to get them.
I would think they were fairly expensive
in their day.

Nate KDS&L


i have no idea what the cost was as i acquired them by mistake when i was ordering evx180s which was about just under 300.00 a piece back then.
i am going to check to see if i still have the frames (i know i have dozens of evx frames that i never got around to re-coning.
Title: Re: Can you find better.
Post by: Peter Harris on January 27, 2007, 10:28:40 PM
Antone,
I am a newbe. I have a related question: is the LAB12 OK for a transmission line application?
I am building a Bailey TL enclosure and looking for a suitable driver.
Thanks for any6 good advice,
Peter
Title: Re: Can you find better.
Post by: Antone Atmarama Bajor on January 29, 2007, 02:13:59 AM
     That depends on what range you want your TL to operate at I suppose.  I thought most TL cabs where "full range" designs  Using the driver mounted on the face of a TL cover a relatively wide range, and possibly mounting a Tweeter on top for better HF extension.

    If you want a basic 2 way TL speaker I would say probably not your best choice.

    I haven't done much real TL Modeling.  I've tried plugging in the dimensions I might use for a TL segment into HORN RESP and seeing what its undamped response might look like but I don't know if its really a valid approach.

    However I do think that Tom Danleys Tapped horns like the DTS-20 can be thought of much like a complex multi segmented Transmission line.  It uses a driver rumored to be a variation on the Lab 12, and is most probably the most powerful subwoofer of its size on the planet.

     I would investigate some of the modeling softwares that are TL specific.  That may give you a better Idea of what can be done with the Lab12 in a TL.  If you want to get response down to at least 20Hz I think it will have to be a rather large or long TL cab/path.

Hope that helps some, as I have no specific answer for you.

Good Luck!!

Antone-
Title: Re: Can you find better.
Post by: Peter Harris on January 29, 2007, 02:48:03 AM
Thanks Antone. I will be using a single TL as a woofer together with a pair of Bose 601 that will cover mid and high range and I plan to cut off the TL close to 1000hz.My amp is a Rotel RA 1062 65W and I have a panel amp also 65W for the woofer with integral adjustable crossover. The set up is for home hi fi . I want to do the TL to replace an Isobaric woofer which is flat but not tight...very vague.
How do you think the crossover will go? I am told to avoid a summing passive crossover.?
Peter.
Title: Re: Can you find better.
Post by: Antone Atmarama Bajor on January 30, 2007, 11:44:26 PM
Lab 12 is not good much past 150-200HZ  I try not to use mine over 80Hz.

    If you wanted to make an acceptable passive xover it would have to be custom designed and optimzed.  You will probably have better luck with an active Xover.

    65 Watts??  A little under powered for the Lab 12.

    I'm guessing this is all just for a home stereo.

    I can't make any value judgement on the Isobaric, as I know what Isobaric is but that doesn't tell me anything else specific about components and design parameters.

   It being flat but not a tight sounding subwoofer doesn't really mean anything to me.  As I don't know what your bassis for comparison, but makes me fell that you may be falling for the legend of the Subwoofer with good Transient response, which is a contradiction.

Anyhow Sounds like fun, I suspect it will need to be quite large.

Antone-