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Hey Petr,

The 8NDL64 is a crazy good deal, probably our highest performance 8" and almost our cheapest as well.
Just hits that convenient sweet spot.
Absolutely. They´re beasts. That was the reason for purchase. 2,5" voice coil and very strong motor will do badass things when driven properly and in groups.
So I really hope I´ll solve that noise issue one way or the other.

Anyway, for hi-fi applications I normally recommend something wider bandwidth like the 8MBX51 or the 8BG51. The NDL series is designed for line arrays, so full range enough but light weight and high power first of all - and assuming subwoofer support.
Yes, I´m well aware. Had this 8MBX51 "decision time" too. Very nice and light driver. The box will experience some regular PA usage though, so more robust motor and larger voice coil with higher impedance (efficiency) will be handy. I probably shouldn´t mention that "Hi-Fi" term. I meant mixed and home usage. Like, EAW KF394NT ballpark of power density and lovely sound. No LA I had a chance to listen to, would touch this. Especially not for close-up listening like 2-5m. And while the stereo speaker set will be made of 4 pieces of 8"s, and I don´t require LA output capabilities, it all fits together so it should work towards the expectations...
I also expect non-conventional design of mine will require a crossover, which will allow the box impedance to drop very low at the crossover point. Here again, higher impedance drivers come in very handy...
I will always use it with subs. For calmer listening sessions, crossover frequency should be around 80Hz, for PA usage, 95-105Hz will do. But it´s all in very early development stage. Time will tell how good decisions I made.
 

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Not exactly knowing JBL drivers (didn´t have these in my hands), but 10PLB76 should trash them both in general use.
But those drivers are not the same. Each have its specifics, and it is possible, that in certain application, JBL can give you better outcome. In other words, evaluating the driver alone is of no use...
Also, "best" answer can only be answered if we know "best in what discipline and application" it is to be used. Same as with "best car", "best meal" or other best things. :)
If I was to pick a 10" from B&C, not minding the weight, it would be exactly 10PLB76. It´s a beast!
 

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Not exactly knowing JBL drivers (didn´t have these in my hands), but 10PLB76 should trash them both in general use.
But those drivers are not the same. Each have its specifics, and it is possible, that in certain application, JBL can give you better outcome. In other words, evaluating the driver alone is of no use...
Also, "best" answer can only be answered if we know "best in what discipline and application" it is to be used. Same as with "best car", "best meal" or other best things. :)
If I was to pick a 10" from B&C, not minding the weight, it would be exactly 10PLB76. It´s a beast!
What would you use the PLB76 for? What application?
 

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How does the 10" B&C 10PLB76 stack up against the JBL 2012H or 2123H? What is B&C's best 10" driver?
Hard to say. JBL has traditionally made a different style of transducer from the majority of commercial suppliers, believe it or not there are "fashion trends" in transducer design and today's call for low Qts, sturdy cones, and stiff suspensions. I don't know anything about these old (or really even most current) JBL transducers: they are not really available for purchase, so not relevant to any of our customers.

Our "best" 10" woofer is always going to be a question of application, which I'd hope is your expertise - not mine! Anyway you can expect that most of our high power designs will be neodymium as that is what the majority of our customers demand.
 

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Hard to say. JBL has traditionally made a different style of transducer from the majority of commercial suppliers, believe it or not there are "fashion trends" in transducer design and today's call for low Qts, sturdy cones, and stiff suspensions. I don't know anything about these old (or really even most current) JBL transducers: they are not really available for purchase, so not relevant to any of our customers.

Our "best" 10" woofer is always going to be a question of application, which I'd hope is your expertise - not mine! Anyway you can expect that most of our high power designs will be neodymium as that is what the majority of our customers demand.
As far as usage goes, with regards to my question regarding the best 10" mid that is available in B&C's product line. The scenereo in which I am curious would be a 3 way tower home theater speaker. One that use a top of the line 1.4" compression driver such as the Radian 951BePb or even the JBL 2453 with a Be diaphragm upgrade on a nice waveguide like the Seos24 or a nice horn like the JBL 2384, using a nice 15" woofer to cover the lows like a JBL 2226 and have the best 10" B&C mid mounted either conventionally or in a mid horn. The 10" B&C mid could cross to the big JBL 2226 at say 250hz on the bottom and cross at say 800hz on top.
 

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As far as usage goes, with regards to my question regarding the best 10" mid that is available in B&C's product line. The scenereo in which I am curious would be a 3 way tower home theater speaker. One that use a top of the line 1.4" compression driver such as the Radian 951BePb or even the JBL 2453 with a Be diaphragm upgrade on a nice waveguide like the Seos24 or a nice horn like the JBL 2384, using a nice 15" woofer to cover the lows like a JBL 2226 and have the best 10" B&C mid mounted either conventionally or in a mid horn. The 10" B&C mid could cross to the big JBL 2226 at say 250hz on the bottom and cross at say 800hz on top.
Why not a 1.4" co-axial compression driver crossed nice and low to a 15" woofer? The BMS 4594 can handle a 375- 400 hz crossover easily.

375 hz wavelength is 36.16", depending on the horn you choose, you might be within 1/4 wavelength at 375 hz. ;)

BMS shows a suggested 300 hz crossover for the 4594ND.

Source: http://www.bmsspeakers.com/fileadmi...1-04_coaxial_neodymium_compression_driver.pdf
 

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I was thinking exactly that. The three way stereo towers topology is close to obsolete now, so if one is to build new system with this "BEST" in his head, he should look elsewhere.

On the other hand, if one is going to build his best nostalgic oldschool setup, but with newer, far more capable components than ever before, I can see that urge too.

While 10PLB76 is very capable driver, and would work in some horns, I wouldn't pick particularly that one for midrange in suggested band and usage.
I would also think twice about the JBL for the bass. Something with Fs of 40Hz and Xmax of 7mm is not that good anymore.
Hope I didn't do more harm then help with this post.
 

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That grin started to creep through towards the end. Gotta love 4 layers of neo wire wrapped around an iron former. Real men love iron formers... :cool:

Shut up and take my money!
Real men love iron formers...
Especially on a shakeweight.
 
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So the B&C 15DS115 is in the literature now, happy to say. Now let's see what kind of evil ideas come up. I am wondering if this might be an option for an upgrade to my mains. Currently I'm running a trio of JBL EON 612M's, and while I was quite surprised at how good they sound for an entry level live sound unit, they run out of steam well before my 21DS115 TH does. Which is notable, as when a threesome of 500 watt 12" 2-ways 11 feet from my nose won't cut it, that's a fairly capable sub. Granted, the EON's are not a stellar unit, but used only for a magazine write-up before I got my hands on them, the price was damn well right.

If size were not an issue, what might be the highest output design a person might come up with to run 60 or 80 to 800hz, that could be feasible for a DIY. Hmmmm ...
 

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So the B&C 15DS115 is in the literature now, happy to say. Now let's see what kind of evil ideas come up. I am wondering if this might be an option for an upgrade to my mains. Currently I'm running a trio of JBL EON 612M's, and while I was quite surprised at how good they sound for an entry level live sound unit, they run out of steam well before my 21DS115 TH does. Which is notable, as when a threesome of 500 watt 12" 2-ways 11 feet from my nose won't cut it, that's a fairly capable sub. Granted, the EON's are not a stellar unit, but used only for a magazine write-up before I got my hands on them, the price was damn well right.

If size were not an issue, what might be the highest output design a person might come up with to run 60 or 80 to 800hz, that could be feasible for a DIY. Hmmmm ...
Tractrix horn loaded 10. :D
 

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I feel less and less sure about how to handle Xmax and Xvar parameters of the B&C. I know what it means on the paper, but it is very different for ones ears. For example IPALs and some new DS driver have Xmax parameter higher than Xvar, and I´m about to believe, that the Xmax is rather the usable cone excursion, but for example 8NDL64 makes much more "distortion" even under Xmax. So these parameters became to be of no use for me.... How easy it was in the old days, without sufficient parameters, and when we were happy enough from the luck we had, if it sounded good. :-D
 

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Hey. Hope it is not a mortal sin to poke this topic with some new dumb question.
After some time, I´m buying second piece of 21DS115, to put it in very compact enclosure .
I was looking at IPAL drivers, but it didn´t look well, value wise (for compact bassreflex box).


Anyway, back to the question.
It has been said, that B&C used Aluminium voice coil winding to put more turns into the magnetic gap, to give it more motor force.
I was digging deeper into this Aluminium voice coil thing, and I still cannot wrap my head around it due to “apparent physics” of things.
One needs to have 1,6x of wire area/volume of Aluminium to get to the conductivity per length compared to Copper.
Then Accounting for Bl, (21SW115 vs 21DS115), on top of that, one needs double the wire length to get to the adequate outcome of Bl.
Then the 21DS115 has longer coil with smaller Resistance.
We´re talking about 3,5x more wire volume here. The magnetic gap possibly cannot be that wide for the flux density it has, can it?
It looks like to me like it cannot work "just like that". I believe B&C left one magic piece of fact away from us in this Aluminium story.. Can anybody help me solving this obvious thing mathematically (Resistance, wire length and volume) so the outcome makes sense?

Thanks.
 

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Another thing to consider is that copper is 3.3X denser than Al, so some (all?) of the benefit additional motor strength will be nullified by having more mass to move.
 

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Yes, I´m aware of that, Yet 21DS115 having greater Mms than 21SW115 and having longer coil doesn´t indicate that there is nullification of things by weight at all. All points to the possibility that there actually is 3,5x more volume of the Al in the coil. But.... HOW THE???
It does make sense until you start with math. Then you find that the wire should not fit in the gap. That dissolves all my lasting brain cells...
 

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I feel less and less sure about how to handle Xmax and Xvar parameters of the B&C. I know what it means on the paper, but it is very different for ones ears. For example IPALs and some new DS driver have Xmax parameter higher than Xvar, and I´m about to believe, that the Xmax is rather the usable cone excursion, but for example 8NDL64 makes much more "distortion" even under Xmax. So these parameters became to be of no use for me.... How easy it was in the old days, without sufficient parameters, and when we were happy enough from the luck we had, if it sounded good. :-D
Hey Petr,

As far as I'm concerned Xvar is the only parameter you should consider. It is based on empirical measurement of the Bl and Kms parameters. Maybe you feel you can get more or less in a particular design from a particular woofer, but the yard-stick of Xvar is consistent and you can apply the same "windage" to any model using that measurement.

Xmax on the other hand is measured using the standard ( 1/2 Hcoil - 1/2 Hgap ) + ( 1/4 Hgap ). It doesn't consider the real parameters of the loudspeaker or suspension limitations whatsoever, so it's easy to make good looking Xmax figures in a loudspeaker that can't actually behave at those levels.
 

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Hey Petr,

As far as I'm concerned Xvar is the only parameter you should consider. It is based on empirical measurement of the Bl and Kms parameters. Maybe you feel you can get more or less in a particular design from a particular woofer, but the yard-stick of Xvar is consistent and you can apply the same "windage" to any model using that measurement.

Xmax on the other hand is measured using the standard ( 1/2 Hcoil - 1/2 Hgap ) + ( 1/4 Hgap ). It doesn't consider the real parameters of the loudspeaker or suspension limitations whatsoever, so it's easy to make good looking Xmax figures in a loudspeaker that can't actually behave at those levels.

Hey Bennett.
Thanks for response. I would generally agree that it is wise to not detach oneself too much from this vital piece of data. Maybe stronger drivers have this advantage where restoring force of the spider and surround is very minor compared to the motor force (and compared with other drivers), so it might push little further with fixed distortion number, yet the speaker still won´t run any far ahead from the issue...

Would you please mind to comment on those "Aluminium winding" speaker differences compared to copper based windings? From parameters, it seems to me like the magnetic gap would need to be huge, or the wire will not fit in there. Yet with huge gap, the magnetic flux would drop badly. I might be missing something, but apparent logic doesn´t work here, as I cannot get to count the wire size and length to fit it into the gap mathematically with these drivers...
 

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Would you please mind to comment on those "Aluminium winding" speaker differences compared to copper based windings? From parameters, it seems to me like the magnetic gap would need to be huge, or the wire will not fit in there. Yet with huge gap, the magnetic flux would drop badly. I might be missing something, but apparent logic doesn´t work here, as I cannot get to count the wire size and length to fit it into the gap mathematically with these drivers...

I'd really like to know the answer to this as well.
 

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It has been said, that B&C used Aluminium voice coil winding to put more turns into the magnetic gap, to give it more motor force.
I was digging deeper into this Aluminium voice coil thing, and I still cannot wrap my head around it due to “apparent physics” of things.
One needs to have 1,6x of wire area/volume of Aluminium to get to the conductivity per length compared to Copper.
Then Accounting for Bl, (21SW115 vs 21DS115), on top of that, one needs double the wire length to get to the adequate outcome of Bl.
Then the 21DS115 has longer coil with smaller Resistance.
We´re talking about 3,5x more wire volume here. The magnetic gap possibly cannot be that wide for the flux density it has, can it?
It looks like to me like it cannot work "just like that". I believe B&C left one magic piece of fact away from us in this Aluminium story.. Can anybody help me solving this obvious thing mathematically (Resistance, wire length and volume) so the outcome makes sense?
Hey Petr,

The short story is that the windings are in fact four layers of aluminum wire, and the gap is larger to accommodate them. It's difficult to compare the DS series to the SW or IPAL series as they are all different designs separately optimized. I asked Italy to provide some more technical information, and here it is:

B&C Speakers SpA said:
The 21SW115 voice coil is a split design, so the BL value has been somewhat reduced to have a more linear force factor behavior even with a large excursion in comparison to a voice coil that does not have the split winding.

The 21DS115 is not a split design and it has a four layer winding, so much more wire is immersed in the magnetic field.

Even if the 4 layer (thicker) winding calls for a larger gap width (this explain the lower flux density of the 21DS115 – 0,8 T instead of 1,15 T of the 21SW115), the resulting BL value is nevertheless higher than that one of the 21SW115.

Essentially: The magnet structure design, its related flux strength inside and outside the gap, and the voice coil winding design establish a complex interaction whose mathematics are far beyond the possibilities of a pocket calculator. No easy formulae here, as far as I know. This is the reason why we use FEA software and have several engineers who are specialists in using it and applying the results to practically manufacturable transducers. It’s the only way to have a meaningful picture of what is happening.
 
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