Lovely value drivers
USRFobiwan,
The 15XB700 and the 15NBX700 look decent
, just a bit of an upgrade from the 15LB100 ....
It seems that moving up to the next level of motor force with 15" PA drivers can get expensive, as in the 15NW100 or the 15SW115 ..
USRFobiwan,
The 15XB700 and the 15NBX700 look decent
, just a bit of an upgrade from the 15LB100 .... It seems that moving up to the next level of motor force with 15" PA drivers can get expensive, as in the 15NW100 or the 15SW115 ..
Put it in a sealed box, use REW to measure response and distortion when subject to frequency sweeps at increasing voltages, use REW to determine when THD crosses 10%, take a note of the voltage, use that in the Hornresp sim and observe what it says about displacement in a sealed box of that size when driven at that voltage level.
Or, if you're already using it in a build, do the same thing outlined above, except use the sim of your build instead.
GKH,
Yes, I have a fold in mind that should work out to around 36" external
Well, I'm really curious!
If i had those drivers i might have to try that
Brian ,
Well alright, if it is really that easy then i might try that here sometime ... . If i understand this correctly the accuracy would depend on how closely the real-world movement of the driver's cone coincides with Hornresp predictions? Right? I wonder why companies like RCF and 18Sound don't just do it like this?
The 15LB100 driver wasn't in my possession .... Sebastian in Denmark owns a few of them and has had his hands on it's big brother the 18-500 as well, which he says look like they have the exact same motor (at least on the outside) when compared side by side, but it is possible that the voicecoil length is different ..... The measured parameters for the 18-500 certainly do look like the exact same motor on a larger cone........
Anyway, we used the voicecoil length and and gap depth provided for the 15LB100 to calculate it's Xmax .... It would be interesting to see how closely that calculated figure matches the actual measured 10% THD figure ..... I was able to talk him into getting the parameters measured by DATS , maybe someday i can talk him into the sealed box with REW method that you described .. . .
Brian ,
Well alright, if it is really that easy then i might try that here sometime ... . If i understand this correctly the accuracy would depend on how closely the real-world movement of the driver's cone coincides with Hornresp predictions? Right? I wonder why companies like RCF and 18Sound don't just do it like this?
The 15LB100 driver wasn't in my possession .... Sebastian in Denmark owns a few of them and has had his hands on it's big brother the 18-500 as well, which he says look like they have the exact same motor (at least on the outside) when compared side by side, but it is possible that the voicecoil length is different ..... The measured parameters for the 18-500 certainly do look like the exact same motor on a larger cone........
Anyway, we used the voicecoil length and and gap depth provided for the 15LB100 to calculate it's Xmax .... It would be interesting to see how closely that calculated figure matches the actual measured 10% THD figure ..... I was able to talk him into getting the parameters measured by DATS , maybe someday i can talk him into the sealed box with REW method that you described .. . .
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I am =)
GKH,
Yessir
That looks like the one that can be downloaded from Thomann...
We had a friend go a step further and had the 15LB100 drivers that he owns measured with a DATS (a Dayton product that measures driver parameters) , and the results of those measurements are what we used to generate the graphic in post #420 ..
GKH,
Yessir
That looks like the one that can be downloaded from Thomann...
We had a friend go a step further and had the 15LB100 drivers that he owns measured with a DATS (a Dayton product that measures driver parameters) , and the results of those measurements are what we used to generate the graphic in post #420 ..
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Maybe it would tell us something about their claims that they don't want us to know, LOL.
Seriously, Klippel measurement has been out for years, but very few driver manufacturers readily provide this data to DIYers like you and me, but they will happily provide "magnet weight", which is basically useless for designing an alignment. If we're using "Xmax" in our sims to determine how much output we can get before noticeable distortion, then it makes sense to measure at a particular peak distortion level that we're willing to accept and work backwards to derive a value for the the driver's "effective" Xmax. It's not a perfect approach, but it will provide results that can be useful in our sims.
aghast
Hehehe, right ...
That thought had crossed my mind!
Maybe the measured 10% THD figure is less impressive than their calculated Xmax.......
*sigh* Marketing.....
Speaking of .... One of our friends in the facebook group just bought himself a Dayton DATS V2 and measured one of the Twisted Sounds brand car audio drivers that had such amazing parameters published (which looked great in our recent cabinet design models in Hornresp) ........ Unfortunately upon first measurements the driver's measured parameters fall short of the published by a long shot ...... Much less motor force than promised ......
He is going to go over his settings, recalibrate and try again tomorrow , but to me this is starting to feel like flashbacks of my experiences with MCM house brand drivers
....
It is astounding that manufacturers and brands can get away with these sorts of shenanigans .....
.................
nevertheless HAPPY HALLOWEEN BRIAN!
Hehehe, right ...
That thought had crossed my mind!
Maybe the measured 10% THD figure is less impressive than their calculated Xmax.......
*sigh* Marketing
.....Speaking of .... One of our friends in the facebook group just bought himself a Dayton DATS V2 and measured one of the Twisted Sounds brand car audio drivers that had such amazing parameters published (which looked great in our recent cabinet design models in Hornresp) ........ Unfortunately upon first measurements the driver's measured parameters fall short of the published by a long shot ...... Much less motor force than promised
...... He is going to go over his settings, recalibrate and try again tomorrow , but to me this is starting to feel like flashbacks of my experiences with MCM house brand drivers
.... It is astounding that manufacturers and brands can get away with these sorts of shenanigans .....
.................
nevertheless HAPPY HALLOWEEN BRIAN!
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Speaking of .... One of our friends in the facebook group just bought himself a Dayton DATS V2 and measured one of the Twisted Sounds brand car audio drivers that had such amazing parameters published (which looked great in our recent cabinet design models in Hornresp) ........ Unfortunately upon first measurements the driver's measured parameters fall short of the published by a long shot ...... Much less motor force than promised
Don't right it off just yet. My DATs failed to measure the B&C 18TBX100 properly, but it seemed to perform Ok. I suspect it had something to do with the low voltage drive of the DATs and the compliance of the 18TBX100. Maybe spend some time putting together the power-amplified version of the REW impedance measurement jig (see link below) and use that to cross-check the measurements with DATs, using a higher-voltage signal to drive the speaker.
Impedance Measurement
Speaking of .... One of our friends in the facebook group just bought himself a Dayton DATS V2 and measured one of the Twisted Sounds brand car audio drivers that had such amazing parameters published (which looked great in our recent cabinet design models in Hornresp) ........ Unfortunately upon first measurements the driver's measured parameters fall short of the published by a long shot ...... Much less motor force than promised
How did the cabinet measure vs the model?
Box plans revamp is underway
BP1Fan,
The original plans for the box based on the published parameters is now no longer appropriate .... Once our friend Barnaby measured the drivers and saw the real T/S parameters he realized that a different cabinet will need to be designed .....
We found out that the measured parameters will work in a Super Planar 8th but the cabinet is large , however he says he does have a lot of space ... We will see .. . Brian also produced an OD-QWP (TL) model which will be a great solution for using up much less space ............ So if Barnaby cannot get Twisted to take these drivers back (and is left stuck with them) at least he has some viable options
BP1Fan,
The original plans for the box based on the published parameters is now no longer appropriate .... Once our friend Barnaby measured the drivers and saw the real T/S parameters he realized that a different cabinet will need to be designed .....
We found out that the measured parameters will work in a Super Planar 8th but the cabinet is large , however he says he does have a lot of space ... We will see .. . Brian also produced an OD-QWP (TL) model which will be a great solution for using up much less space ............ So if Barnaby cannot get Twisted to take these drivers back (and is left stuck with them) at least he has some viable options
Yes, that is right
Luca,
Circlomanen is correct ....
Many people just refer to the OD-QWP or even just the QWP as a "TL" (Transmission Line) .....
An OD-QWP is not extreme (in terms of SPL or efficiency) when compared to the high performance cabinets that we have been discussing here but It would be a very easy way for you to get the bass extension that you want in a compact cabinet, and the driver requirements aren't nearly as demanding ....
It may be exactly what you are looking for.
You can even go about it in a fancy and fun way by building an offset-driver quarterwave Karlson inspired variant called the "Karlflex" and loading it with a 15" driver like the 15LB100 ... Using the low-tuned option like Mr Mattcalf from Australia went with you will get solid response right down to 30hz with enough SPL to satisfy you in the living room, especially with a pair ....
Luca , this is all going off-topic here though so if you are interested just send me a message in private and i will respond with links to plans and details ..
Luca,
Circlomanen is correct ....
Many people just refer to the OD-QWP or even just the QWP as a "TL" (Transmission Line) .....
An OD-QWP is not extreme (in terms of SPL or efficiency) when compared to the high performance cabinets that we have been discussing here but It would be a very easy way for you to get the bass extension that you want in a compact cabinet, and the driver requirements aren't nearly as demanding ....
It may be exactly what you are looking for
.You can even go about it in a fancy and fun way by building an offset-driver quarterwave Karlson inspired variant called the "Karlflex" and loading it with a 15" driver like the 15LB100 ... Using the low-tuned option like Mr Mattcalf from Australia went with you will get solid response right down to 30hz with enough SPL to satisfy you in the living room, especially with a pair ....
Luca , this is all going off-topic here though so if you are interested just send me a message in private and i will respond with links to plans and details ..
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Many thanks to Matthew an Circlomanen for the fast
replay ! But if the OD-KWP is a Karlson or similar
I prefer to know more about the
Super Planar 8th configuration
Karlson hasn't a very clean and tight bass , and only a little gain
at the very bass frequency....
for the low frequency I prefer a simply double reflex
enclosure with bigs ducts ( a third of Sd for each one or a little more)
also if then I'll have only a pair of octave of extension or little more.
replay ! But if the OD-KWP is a Karlson or similar
I prefer to know more about the
Super Planar 8th configuration
Karlson hasn't a very clean and tight bass , and only a little gain
at the very bass frequency....
for the low frequency I prefer a simply double reflex
enclosure with bigs ducts ( a third of Sd for each one or a little more)
also if then I'll have only a pair of octave of extension or little more.
Luca , the original Karlsons were a completely different animal , but there are some modern K inspired variants which are Offset-Driver Quarterwave based designs like the "Karlsonator" and the "Karlflex" , so that is why i mentioned the one that i came up with ...
OD-QWP style TL cabinets can be made compact and can tune low ....They have wide bandwidth and are simple
.... 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.
We are currently building a nice little OD-QWP for a RCF LF18X401.
A great home-theater subb for my 15 year old son.
We are going to build a ROAR18 for this driver later on, but it is totally unusable in a home environment.
Measured parameters may not be what is published but still useful ..
Update on the Twisted TSX1000 12" D4s
After being measured by Barnaby Lange via DATS we were all disappointed to find out that the T/S parameters were not remotely matching the published parameters from Twisted's website, but after some work in Honresp we can see that these measured parameters are still useful... This sim is in Halfspace (open field) and this same box could be made smaller at around 450 liters for usage in a vehicle (add +18db roughly, depending on vehicle) ... Not bad at all really , just a big box ... These can also easily be made to work in smaller cabinets of other designs (with less output) .. .
Update on the Twisted TSX1000 12" D4s
After being measured by Barnaby Lange via DATS we were all disappointed to find out that the T/S parameters were not remotely matching the published parameters from Twisted's website, but after some work in Honresp we can see that these measured parameters are still useful... This sim is in Halfspace (open field) and this same box could be made smaller at around 450 liters for usage in a vehicle (add +18db roughly, depending on vehicle) ... Not bad at all really , just a big box ... These can also easily be made to work in smaller cabinets of other designs (with less output) .. .