@Globalplayer, my thoughts exactly! For such driver with so much motor (magnet) it has pretty low bl. Did you see the Russian Pride S v.3 subwoofer, it's BL is 30. 36mm xmax, you can stand on the cone.
Globalplayer ,
The BL alone is completely meaningless, you need Re to make it meaningful ....... Notice how low the Re is here ..... . Apply the BL^2/Re formula to properly compare it against other drivers with different impedances , otherwise it is not a fair comparison ... .
You will find that the DDX 12 driver has quite a lot of motor force , plenty to control 280 grams of moving mass ....... No problem at all ...
Use the BL^2/Re formula guys!
BL alone is meaningless...
This driver is VERY strong ...
If you want i can calculate out the equivalent BL for this driver as if it were an 8 ohm driver just to demonstrate how strong the driver really is ..
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B&C 18IPAL has the same "problem" of "only" 24,5 in Bl and a Mms of 330 grams.
The really low Qts of 0,14 tells another story though.....
The SKAR DDX12D2 seems like a very nice driver. Somewhat similar in performance to a GAS PRO 12D2 or a GAS Alpha 12D2 (also a Qts of 0,33). GAS could be an available option in Europe.
Nice find! Extremely good bang for the buck. It should give an outstanding performance, even compared to top dollar pro audio drivers.
Regards,
Johannes
The really low Qts of 0,14 tells another story though.....
The SKAR DDX12D2 seems like a very nice driver. Somewhat similar in performance to a GAS PRO 12D2 or a GAS Alpha 12D2 (also a Qts of 0,33). GAS could be an available option in Europe.
Nice find! Extremely good bang for the buck. It should give an outstanding performance, even compared to top dollar pro audio drivers.
Regards,
Johannes
Yes, I know.
Low impedance...
But...
280g are 280g.
No matter how high the motor force.
Talking about transients/overshoots.
Equivalent BL calculations using Hornresp
Ok , just worked it out ....
If the DDX 12 were an 8 ohm driver (with an Re of 6):
It's BL factor would be 34.52
This sort of motor force is more than enough to control 280g of moving mass on an 8 ohm driver in a subwoofer application.... If you like i can bring up plenty of examples of PA drivers that have a similar amount of moving mass and LESS motor force ...
This is really easy to calculate out using Hornresp ....... It is just a matter of entering your new Re value and then clicking on the BL field , and it will ask for the driver's Fs and Qes again ... No need to touch anything else unless you will want to do some modeling with the altered Re , and in that case you will need to raise the Le (inductance) accordingly .... For example if you are multiplying the Re by a factor of 6 then you will have to multiply the initial Le by a factor of 6 ..
Ok , just worked it out ....
If the DDX 12 were an 8 ohm driver (with an Re of 6):
It's BL factor would be 34.52
This sort of motor force is more than enough to control 280g of moving mass on an 8 ohm driver in a subwoofer application.... If you like i can bring up plenty of examples of PA drivers that have a similar amount of moving mass and LESS motor force ...
This is really easy to calculate out using Hornresp ....... It is just a matter of entering your new Re value and then clicking on the BL field , and it will ask for the driver's Fs and Qes again ... No need to touch anything else unless you will want to do some modeling with the altered Re , and in that case you will need to raise the Le (inductance) accordingly .... For example if you are multiplying the Re by a factor of 6 then you will have to multiply the initial Le by a factor of 6 ..
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Matthew the BL^2/Re = 194.5 is really powerful I agree, compared to for example the a pro driver B&C 12TBX100 which has a BL^2/Re = 127.5.
For a car build it will probably work wonders and totally acceptable for short periods.
However I would love to see how long this driver will last 7+ hours at war volume.
I have tested car audio sub drivers in a PA environments and after a few hours of abuse most of the time they will simply give ups something (mostly the voice coil).
For a car build it will probably work wonders and totally acceptable for short periods.
However I would love to see how long this driver will last 7+ hours at war volume.
I have tested car audio sub drivers in a PA environments and after a few hours of abuse most of the time they will simply give ups something (mostly the voice coil).
USRFobiwan,
Heat buildup is definitely something to consider , after all the motor is having to push against a very stiff suspension on top of the moving mass , along with some substantial resonant loading from the high-order cabinet as well as the long column of air in the horn ....... That is a lot to be shoving back and forth ....
But then again if we are comparing two of the DDX 12s against a similarly priced 18" PA driver then we are talking about two different heavy duty voicecoils splitting the power that would be sent to the single 18" PA driver's voicecoil ...........
It would be a fun and interesting experiment to torture both options in high order cabinets, both driven with enough power to reach the high 120s decibel range to see which option fails first ...
Remember The Labhorn?
People gushed and gushed about the Labhorn for years .... It was considered a serious subwoofer for PA but it used two 12" drivers that are hardly indistinguishable from well built Car Audio subs (ones which honestly aren't even remotely as capable as these DDX 12s) ....
This is a situation where we are once again utilizing two drivers of this style loaded into a large PA horn for bass and subbass ...
I have the Labhorn inputs for Hornresp so it is easy for me to simulate ..... If you guys are curious i can overlap the Labhorn's curve and the Paraflex 2x12 curve ..... The Paraflex 2x12 is considerably smaller, you guys might be surprised by the results ...... I haven't done it yet but if anyone would like to see it i will gladly put it together and post it FOR THE SAKE OF SCIENCE!!!
People gushed and gushed about the Labhorn for years .... It was considered a serious subwoofer for PA but it used two 12" drivers that are hardly indistinguishable from well built Car Audio subs (ones which honestly aren't even remotely as capable as these DDX 12s) ....
This is a situation where we are once again utilizing two drivers of this style loaded into a large PA horn for bass and subbass ...
I have the Labhorn inputs for Hornresp so it is easy for me to simulate ..... If you guys are curious i can overlap the Labhorn's curve and the Paraflex 2x12 curve ..... The Paraflex 2x12 is considerably smaller, you guys might be surprised by the results ...... I haven't done it yet but if anyone would like to see it i will gladly put it together and post it FOR THE SAKE OF SCIENCE!!!
More driver chat
Hehehe, well i suppose it is
USRFobiwan , you said there are no Skar dealers in Europe? I understand it is really easy to get a dealership arrangement with them, do you have any local friends that work in the Car Audio biz? Maybe they would want to contact Skar and get set up ....
Anyway, are the "Massive" brand subs being sold in Europe? The GTX 10 looks like it has tremendous potential (and sells for half the price of the DDX12) .... Still need to verify the parameters on the GTX 10 though ...
We have a guy that is about to measure a really tough looking Soundqubed driver , hopefully those parameters will be useful , we will know soon enough ...
Mr Vansickle measured a few Ultimax 8 drivers recently and they look alright, in fact the measured parameters were surprisingly just slightly better than the published!
FURTHERMORE we will have a PA driver related update coming soon .... We have a friend in California building a Paraflex for a B&C iPAL 18 (the cabinet can actually host two of them when he buys a second) .... The initial build should be done this week ...... This will be the very first Paraflex loaded with a Pro driver in the real world!
hahaha! I always saw the LAB sub as a glorified car sub.
Hehehe, well i suppose it is
USRFobiwan , you said there are no Skar dealers in Europe? I understand it is really easy to get a dealership arrangement with them, do you have any local friends that work in the Car Audio biz? Maybe they would want to contact Skar and get set up ....
Anyway, are the "Massive" brand subs being sold in Europe? The GTX 10 looks like it has tremendous potential (and sells for half the price of the DDX12) .... Still need to verify the parameters on the GTX 10 though ...
We have a guy that is about to measure a really tough looking Soundqubed driver , hopefully those parameters will be useful , we will know soon enough ...
Mr Vansickle measured a few Ultimax 8 drivers recently and they look alright, in fact the measured parameters were surprisingly just slightly better than the published!
FURTHERMORE we will have a PA driver related update coming soon .... We have a friend in California building a Paraflex for a B&C iPAL 18 (the cabinet can actually host two of them when he buys a second) .... The initial build should be done this week ...... This will be the very first Paraflex loaded with a Pro driver in the real world!
Paraflex Pro is about to be born , sometime this week
You got it right USRF
The guy in California, that is Barnaby 
...
He bought the iPAL 18 a little while ago and loaded it into a reflex cabinet with large port, and that is how he used it up until the present. ... .
He is finally just now building the Paraflex for his iPAL... He might not be done for a few more days so you still have time Obiwan! hehehe
bummer and I thought i would be the first
Ricky beat me to it a few months or was it Barnaby? haha
You got it right USRF
The guy in California, that is Barnaby ...He bought the iPAL 18 a little while ago and loaded it into a reflex cabinet with large port, and that is how he used it up until the present. ... .
He is finally just now building the Paraflex for his iPAL... He might not be done for a few more days so you still have time Obiwan! hehehe
J R Vansickle of Paragon Concept in North Carolina owns a Smith & Larson Woofertester2 unit and has been measuring drivers lately ..
Yesterday he measured a truly remarkable driver ... It is the Skar Audio brand DDX 12, and we have some very exciting news to report!
The measured Parameters are extraordinarily suitable for our high-order cabinets like the Paraflex and the Super Planar 8th!!!
This is such a breath of fresh air after all of the disappointments we have experienced with Car Audio drivers lately
NOTE: The DDX 12 is most appropriate for cabinets tunings in the 33hz to 40hz range (the suspension is extremely tight , low compliance , so tuning far below the driver's Fs value is not really an option , Group Delay becomes an issue)
Ok guys , here they are:
Measured by J Vansickle of Paragon Concept
SKAR DDX 12" D2 (broken in)
Jan 7th 2018
Re = 0.9790 ohms
Fs = 38.4740 Hz
Zmax = 15.7128 ohms
Qes = 0.3420
Qms = 5.1471
Qts = 0.3207
Le = 1.0710 mH (at 1 kHz)
Diam = 254.0000 mm ( 10.0000 in )
Sd = 50670.7504 mm^2( 78.5398 in^2)
Vas = 22.2787 L ( 0.7868 ft^3)
BL = 13.9235 N/A
Mms = 280.1522 g
Cms = 61.0817 uM/N
Kms = 16371.5244 N/M
Rms = 13.1576 R mechanical
Efficiency = 0.3486 %
Sensitivity= 87.4414 dB @1W/1m
Sensitivity= 96.5646 dB @2.83Vrms/1m
Krm = 5.142E-03 ohms Freq dependent resistance
Erm = 721.087E-03 Rem=Krm*(2*pi*f)^Erm
Kxm = 22.562E-03 Henries Freq dependent reactance
Exm = 655.496E-03 Xem=Kxm*(2*pi*f)^Exm
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Here is a quick simulated Paraflex curve (below) .... I will post more detailed sims and curves in the near future as I put them together ..
This is two of the DDX 12s in a 210-ish liter 35hz tuned Paraflex using the "Lossy Le" mode in Hornresp ..... Driven to around the Xmax rating , maybe slightly over by 1mm or two , still in the very safe range
It is the estimated "in-vehicle" response which isn't quite 18db over Halfspace , and we are finding that this method is conservative ..
An externally hosted image should be here but it was not working when we last tested it.
If anyone is curious about the output in HALFSPACE I can tell you that two of these drivers in the 35hz tuned 210-ish liter cabinet produces about 130db at full power , and has solid response right down to 35hz , upper limits would probably be at least around 90hz before response starts to dwindle above that .............................. To put things into perspective it is nearly impossible to find a 18" PA driver for $320 that can match this output and extension in a 200 liter quarterwave loaded cabinet ....... PA 18s that are capable of this are usually much more expensive than $320 ...
Two of the DDX 12s can displace about as much air as an 18" driver with 15mm of linear one-way cone travel and has a combined power handling of 2000w RMS ..
SKAR DDX 12
WELL DONE SKAR!!! BRAVO!!!
Look at what I got 4 xmas!
I got a DATS too.
I just don't have the room behind the seat for 1 of your enclosures. I'm either going BP4 or tapped pipe (TQWP).
Attachments
Santa gave you Skars for Xmas! Hehehehe
Even better yet he gave you Skars and VDs !!
Four different VDs even!!
That dirty damned Santa 
..... When it comes to VDs sometimes sharing is not caring 
. Good to hear that you have a DATS BP1fan! They are so incredibly useful
When you measure those Skars be sure to let us know what the results are , it would be much appreciated
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