Duel 12 T60 changing from labs

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Armchair Pirate
Posts: 60
Joined: Wed Jun 29, 2011 11:53 am

Duel 12 T60 changing from labs

#1 Post by Armchair Pirate » Fri Mar 20, 2020 4:06 pm

It's been quite some time since I've posted here but I've stumbled across some 12-inch drivers that I would like to replace the labs with. It's only $100 more per pair. But they are 2000-watt continuous. Using the information provided do you guys think this would be a good idea?

B&C 12NW100-4 12
Resonance Frequency 44 Hz
Re3.8 ?
Qes0.21
Qms5.8
Qts0.2
Vas43.3 dm3 (1.53 ft3)
Sd531.0 cm2 (82.3 in2)
??1.69 %
Xmax9.0 mm
Xvar10.0 mm
Mms120.0 g
Bl24.38 Txm
Le1.79 mH
EBP209 Hz

Nominal Diameter320 mm (12.0 in)
Nominal Impedance4 ?
Minimum Impedance5.0 ?
Nominal Power Handling1000 W
Continuous Power Handling2000 W
Sensitivity92.0 dB
Frequency Range45 - 1500 Hz
Voice Coil Diameter100 mm (4.0 in)
Winding MaterialCopper
Former MaterialGlass Fibre
Winding Depth25.0 mm (1.0 in)
Magnetic Gap Depth12.0 mm (0.5 in)
Flux Density1.2 T
Built so far
4x Duel Lab 12 T60 30"

Next
2x DR280
2x D12 T60

SethRocksYou
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Location: Sacramento, California, USA
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Re: Duel 12 T60 changing from labs

#2 Post by SethRocksYou » Fri Mar 20, 2020 4:20 pm

With less Vd, it would be a step backward.

Only 478cc to the LAB's 659cc

Go ahead though, I'll buy your LABs :mrgreen:

Armchair Pirate
Posts: 60
Joined: Wed Jun 29, 2011 11:53 am

Re: Duel 12 T60 changing from labs

#3 Post by Armchair Pirate » Fri Mar 20, 2020 4:24 pm

Even with almost 4x the power handling?
Built so far
4x Duel Lab 12 T60 30"

Next
2x DR280
2x D12 T60

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Bill Fitzmaurice
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Re: Duel 12 T60 changing from labs

#4 Post by Bill Fitzmaurice » Fri Mar 20, 2020 4:46 pm

Armchair Pirate wrote:
Fri Mar 20, 2020 4:24 pm
Even with almost 4x the power handling?
Read page 2 of your plans. The Qes is also way too low, Fs is too high, and 1000w isn't four times 400w.

Grant Bunter
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Re: Duel 12 T60 changing from labs

#5 Post by Grant Bunter » Fri Mar 20, 2020 4:53 pm

My older T60 plans don't show the usual desired target TS specs for drivers for that cab, probably because the only recommended drivers are either 2 x lab12 or 1 x lab15.

So, what's different with the driver you've put up for consideration?
Seth has already pointed out Vd is lower.
As well as that, Xmax is lower, impedance is lower, Qts is lower, Fs is higher.
Also, no where in the literature I could easily find, does it say the B&C above is suited to horn loading, the SPL chart isn't standard, and I'll stop there.

You can't just look at "2000W" even though it's up top in flashing neon ready to be a dangling carrot :)
And just to show you why, it says 2000W continuous up the top, but 1000W nominal down the bottom on the spec sheet I found

When you find what you think are appropriate drivers, check out the specs of what's recommended, and see if what you're looking at is within 10% of all specs. One TS spec may be a little out, but still may get a nod from the designer (eg Bill)

Then the questions become, what would be the voltage limit (because it's actually a voltage displacement limit)?
And if that's no better, then it's not a good replacement option.

It's said so many times on the forum, if you want more volume, add more cabs...

http://www.bcspeakers.com/en/products/l ... w100-4.pdf
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

Armchair Pirate
Posts: 60
Joined: Wed Jun 29, 2011 11:53 am

Re: Duel 12 T60 changing from labs

#6 Post by Armchair Pirate » Fri Mar 20, 2020 5:03 pm

I've been through enough speakers to know that the wattage rating, taken at face value could be Peak, continuous or just flat outright bulshit. With that being said. These are B&C drivers, which are really damn good drivers. I don't know where you're reading the 1000 watt because the literature I found says it's 2000 watt continuous 4000 Watt peak. Reason I was asking for input is because things like qts, fs and xmax are things that I don't understand.
Built so far
4x Duel Lab 12 T60 30"

Next
2x DR280
2x D12 T60

Grant Bunter
Posts: 6355
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: Duel 12 T60 changing from labs

#7 Post by Grant Bunter » Fri Mar 20, 2020 5:17 pm

Armchair Pirate wrote:
Fri Mar 20, 2020 5:03 pm
I've been through enough speakers to know that the wattage rating, taken at face value could be Peak, continuous or just flat outright bulshit. With that being said. These are B&C drivers, which are really damn good drivers. I don't know where you're reading the 1000 watt because the literature I found says it's 2000 watt continuous 4000 Watt peak. Reason I was asking for input is because things like qts, fs and xmax are things that I don't understand.
They can be damn good drivers, and not work well in horns.

Where I got my figures is from the link I posted, but I'll post it again
http://www.bcspeakers.com/en/products/l ... w100-4.pdf
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

Grant Bunter
Posts: 6355
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: Duel 12 T60 changing from labs

#8 Post by Grant Bunter » Fri Mar 20, 2020 5:24 pm

Just so you know, driver displacement limits are calculated by Bill, based on modelling in his designs, and working through TS specs from highest importance to lowest.

So, highest importance is Xmax and impedance.
All the rest are less important to varying degrees, but, in this case, the B&C has both lower impedance, and Xmax.
While lower impedance often leads to a lower voltage limit (yet output will be the same if Xmax was similar), I think once Vd is thrown into the equation output will not be perhaps what you might expect based on the manufactures chart...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

jimbo7
Posts: 684
Joined: Fri Dec 28, 2012 10:45 am
Location: St. Louis

Re: Duel 12 T60 changing from labs

#9 Post by jimbo7 » Fri Mar 20, 2020 6:01 pm

So are your Labs are for sale?
BFM builds:
XF212
T24 BP102 24"
2x SLA's 6-5" mids, 9- gt-302's
2x AT 14" MCM 55-2421
TrT 5" MCM 55-2421
AT 18" JBL GTO804
2x OT12 flat array
2x SLA Pro 2-Alpha 6's 2-Goldwoods
2x T39 24" 3012lf
Simplex 10 BP102

Armchair Pirate
Posts: 60
Joined: Wed Jun 29, 2011 11:53 am

Re: Duel 12 T60 changing from labs

#10 Post by Armchair Pirate » Fri Mar 20, 2020 6:41 pm

Grant, I'm sorry that I didn't see you posted the link the first time. But even on your link it says 2000 watt continuous . Also, I understand that bill was very specific with his calculations which is why I came to this forum to ask for advice rather than just buying drivers and slapping them in. I was hoping that the significantly higher power handling at 4 Ohms would cause the cabs to thump even harder, especially in the 60hz range. Unfortunately, outside of continuous power and ohm rating I don't understand what any of those other numbers mean. which is another reason I was asking for advice. Jimbo, if it turned out these drivers were going to be a significant Improvement then my labs would be for sale. They're practically brand new and the revamped, higher power 600 watt versions. I appreciate your time.
Built so far
4x Duel Lab 12 T60 30"

Next
2x DR280
2x D12 T60

SethRocksYou
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Joined: Thu Sep 10, 2009 8:06 pm
Location: Sacramento, California, USA
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Re: Duel 12 T60 changing from labs

#11 Post by SethRocksYou » Fri Mar 20, 2020 7:44 pm

Armchair Pirate wrote:
Fri Mar 20, 2020 5:03 pm
Reason I was asking for input is because things like qts, fs and xmax are things that I don't understand.
https://www.eminence.com/support/unders ... aker-data/

Grant Bunter
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Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
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Re: Duel 12 T60 changing from labs

#12 Post by Grant Bunter » Fri Mar 20, 2020 7:45 pm

Armchair Pirate wrote:
Fri Mar 20, 2020 6:41 pm
Grant, I'm sorry that I didn't see you posted the link the first time. But even on your link it says 2000 watt continuous .

Yes, it does, at the top. And 1000W nominal at the bottom, so which one is correct? It doesn't say peak 4000W anywhere in the one I posted up.

Also, I understand that bill was very specific with his calculations which is why I came to this forum to ask for advice rather than just buying drivers and slapping them in.

Yes. And he's already mentioned that Qes is to low, Fs to high. Asking for advice is always a great move :)

I was hoping that the significantly higher power handling at 4 Ohms would cause the cabs to thump even harder, especially in the 60hz range. Unfortunately, outside of continuous power and ohm rating I don't understand what any of those other numbers mean. which is another reason I was asking for advice.

That's ok. There's plenty of great resources on the net that will tell you what all the TS specs are and what they mean, but it can take a little longer to understand them. Just google "What do Thiele Small paramaters mean?"

Going to 4 ohm drivers within itself can be a bad move, it depends on driver response, especially if you wire parallel in cab and not in series (in this particular case), and amplifier stable load capability.
Why?
Because if you ignore acoustic impedance from the cab itself (and I always do when working out amp loads), then parallel wired, you have a 2 ohm nominal load per amp channel, you require a 2 ohm load stable amp, and, even if you already have one, you're running it as hard as you can, which reduces amp life, increases incidence of thermal shutdown, blah blah blah. There will also be certain frequencies below 2 ohms.


Jimbo, if it turned out these drivers were going to be a significant Improvement then my labs would be for sale. They're practically brand new and the revamped, higher power 600 watt versions.

I'm wondering, when Bill says 400W, that is a voltage displacement limit based on both Xmax and thermal limits
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

SethRocksYou
Posts: 904
Joined: Thu Sep 10, 2009 8:06 pm
Location: Sacramento, California, USA
Contact:

Re: Duel 12 T60 changing from labs

#13 Post by SethRocksYou » Fri Mar 20, 2020 8:52 pm

Armchair Pirate wrote:
Fri Mar 20, 2020 4:24 pm
Even with almost 4x the power handling?
Power handling is how much power it can take before the coil melts.

Vd is the displacement of the cone, which directly correlates to volume. More Vd, more volume. It's calculated from the surface area of the cone, Sd (the old πr²), multiplied by the distance the cone travels, xMax.

If you want more output, find a driver with higher Vd. :thumbsup:

Armchair Pirate
Posts: 60
Joined: Wed Jun 29, 2011 11:53 am

Re: Duel 12 T60 changing from labs

#14 Post by Armchair Pirate » Fri Mar 20, 2020 9:22 pm

Thank you to everyone who took the time to respond. I wish you all the best.
Built so far
4x Duel Lab 12 T60 30"

Next
2x DR280
2x D12 T60

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Bill Fitzmaurice
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Joined: Tue May 02, 2006 5:59 pm

Re: Duel 12 T60 changing from labs

#15 Post by Bill Fitzmaurice » Fri Mar 20, 2020 9:31 pm

SethRocksYou wrote:
Fri Mar 20, 2020 8:52 pm
If you want more output, find a driver with higher Vd.
It also must have specs within the usable range as stated in the plans. That's the first thing one must do when considering a driver, in any and all of our designs.

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