phl 3450/3451 lower midrange response and crossover

thadman · 23rd October 2007, 08:40 PM

I've been doing some research and the PHL 3451 seems like an excellent driver suitable as a lower midrange. Other than some vague information, PHL doesn't provide much data concerning these drivers beyond thiele small parameters. I'd like to use them between 150 and 600hz mated to the ATC super dome.

#1 does anybody have FR graphs, distortion/csd graphs for these drivers? I'm very interested in FR graphs because these drivers are listed as high efficiency (100dB)...but at what frequency?

#2 How would these drivers handle a 150hz crossover (I'm going active, 24dB seems likely but 48dB is a possibility)? Could they still play with the utmost authority and fidelity at high SPLs, I'm not looking for any signs of strain. I'm not willing to cross any higher than 150hz.

#3 How much usable xmax do these drivers have. It's listed at 2.5mm, but how much of that is 99% strength?

#4 Where can I purchase these drivers?

#5 How do these drivers compare to the likes of 18sounds midbass/midrange offerings (10NdA520, 12NdA520)

Nelson Pass · 23rd October 2007, 09:46 PM

Quote:

Originally posted by thadman
#2 How would these drivers handle a 150hz crossover (I'm going active, 24dB seems likely but 48dB is a possibility)? Could they still play with the utmost authority and fidelity at high SPLs, I'm not looking for any signs of strain. I'm not willing to cross any higher than 150hz.

Hell, I cross them at 60 Hz with a single-pole and they don't
burp.

Cloth Ears · 24th October 2007, 12:20 AM

Quote:

Originally posted by Nelson Pass

Hell, I cross them at 60 Hz with a single-pole and they don't
burp.

Ahhh! The Rushmore. I always wondered if they were the 3450. I never thought that they would go as low as that, but I might have to change my crossover a bit now.

Thanks, Nelson!

thadman · 24th October 2007, 02:26 AM

At 150hz, won't we effectively be operating in 1/8th space if placed in a corner? Thats an extra 18dB vs full space.

377cm^2 (.375mm linear excursion) should achieve 92dB at 150hz

92dB operating in 1/8th space=
20(10^(92/20))=796214.34

796214.3411(8)=6369714.73

20log(6369714.73/20)=~110dB

Cloth Ears · 24th October 2007, 03:10 AM

Hi thadman,

From the literature on Nelson's Rushmore:
Within “Rushmore” there is sufficient Single-ended “Class A” amplification to routinely achieve 120 dB peaks with negligible acoustic distortion.

This includes a 3450 high-passed at 60Hz. So, if you can believe Nelson (and many do) then crossing at 150Hz should provide no problems...

thadman · 27th October 2007, 06:36 PM

It has a 90(+/-18)hz free air resonance, and you're operating it down to 60hz. I'm not questioning your experience, just wondering if we're talking about the same driver.

Magnetar · 27th October 2007, 10:53 PM

I had the 3451 - using it below 200 cycles is just plain nuts.

27th October 2007, 06:36 PM	#6
thadman diyAudio Member Join Date: Dec 2005 Location: west lafayette	It has a 90(+/-18)hz free air resonance, and you're operating it down to 60hz. I'm not questioning your experience, just wondering if we're talking about the same driver. __________________ "It is a profound and necessary truth that the deep things in science are not found because they are useful; they are found because it was possible to find them."

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23rd October 2007, 08:40 PM	#1
thadman diyAudio Member Join Date: Dec 2005 Location: west lafayette	phl 3450/3451 lower midrange response and crossover I've been doing some research and the PHL 3451 seems like an excellent driver suitable as a lower midrange. Other than some vague information, PHL doesn't provide much data concerning these drivers beyond thiele small parameters. I'd like to use them between 150 and 600hz mated to the ATC super dome. #1 does anybody have FR graphs, distortion/csd graphs for these drivers? I'm very interested in FR graphs because these drivers are listed as high efficiency (100dB)...but at what frequency? #2 How would these drivers handle a 150hz crossover (I'm going active, 24dB seems likely but 48dB is a possibility)? Could they still play with the utmost authority and fidelity at high SPLs, I'm not looking for any signs of strain. I'm not willing to cross any higher than 150hz. #3 How much usable xmax do these drivers have. It's listed at 2.5mm, but how much of that is 99% strength? #4 Where can I purchase these drivers? #5 How do these drivers compare to the likes of 18sounds midbass/midrange offerings (10NdA520, 12NdA520) __________________ "It is a profound and necessary truth that the deep things in science are not found because they are useful; they are found because it was possible to find them."

24th October 2007, 02:26 AM	#4
thadman diyAudio Member Join Date: Dec 2005 Location: west lafayette	At 150hz, won't we effectively be operating in 1/8th space if placed in a corner? Thats an extra 18dB vs full space. 377cm^2 (.375mm linear excursion) should achieve 92dB at 150hz 92dB operating in 1/8th space= 20(10^(92/20))=796214.34 796214.3411(8)=6369714.73 20log(6369714.73/20)=~110dB __________________ "It is a profound and necessary truth that the deep things in science are not found because they are useful; they are found because it was possible to find them."

24th October 2007, 03:10 AM	#5
Cloth Ears diyAudio Member Join Date: Dec 2001 Location: Melbourne, Australia	Hi thadman, From the literature on Nelson's Rushmore: Within “Rushmore” there is sufficient Single-ended “Class A” amplification to routinely achieve 120 dB peaks with negligible acoustic distortion. This includes a 3450 high-passed at 60Hz. So, if you can believe Nelson (and many do) then crossing at 150Hz should provide no problems... __________________ Jont. "It is impossible to build a fool proof system; because fools are so ingenious."

27th October 2007, 10:53 PM	#7
Magnetar Banned Join Date: Feb 2004 Location: Portal 2012	I had the 3451 - using it below 200 cycles is just plain nuts.