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One test my 20-39PC+ failed.


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#1 of 30 OFFLINE   Jesse Sharrow

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Posted April 12 2004 - 04:59 AM

First of all I want to you all to know that I love this thing. It is by far the best sub I have ever seen. As I have said the only sub I have ever heard that came close was the martin logan descent retailing for $2000 more than the SVS.

Now I have thrown alot of tests at this thing. Music, movies, you name it. It excells at music. Blows away the $2000 kef reference sub at work. Its alot more accurate.

Movies are incredible. Very powerful and it can play low.

The only thing that the Martin logan beat it at is the Nickel test. The martin logan descent is so solid you can put a nickel on the top of it on its edge. Then crank it and it wont fall off... well the SVS did this. I played some linkin park DVD-Audio and it stayed up... until I threw in monsters inc. Then it fell over. LOL. You guys proably think Im nuts. But Im still impressed. Just really low bass at reference level is what made it fall over. Im gonna leave a penny on it for a week see how many times it falls over.

Posted Image Posted Image Im listening to metallica DVD-Audio Black Album right now. Its incredible. I love this thing. No doubts at all in my mind.

#2 of 30 OFFLINE   MingL

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Posted April 12 2004 - 05:12 AM

Exactly what is the nickle edge test suppose to prove anyway? At bass frequencies, the sub is supposed to move all the air it can move. the moving air is proably what prevents the nickle from balancing on its edge.

Just curious coz this is the first time I've heard of a nickle edge test to decide the quality of a sub.

#3 of 30 OFFLINE   ScottCHI

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Posted April 12 2004 - 05:16 AM

he said that that was but one of the tests in "jesse's subwoofer gauntlet"
"All men are frauds. The only difference between them is that some admit it. I myself deny it."

#4 of 30 OFFLINE   Jesse Sharrow

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Posted April 12 2004 - 05:25 AM

To put it simply I dont care that it failed it!

#5 of 30 OFFLINE   Andy F

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Posted April 12 2004 - 05:31 AM

The nickel test relates to cabinet vibration. The Descent won't vibrate enough to tip a nickel over when placed on it's side on top of the sub. This speaks a lot to the sub/cabinet engineering.

With that said, would you notice a difference between the two other than the nickel?.... I'm not sure.

#6 of 30 OFFLINE   Edward J M

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Posted April 12 2004 - 06:26 AM

The ML design uses more than one driver, configured in such a fashion that reactive forces are cancelled.

The SVS 20-39PC+ uses a single downward-firing woofer which naturally can transmit some reactive forces. The fact that the sub can actually move on a smooth floor (unless the included compliant rubber feet are installed) at very high playback volumes is testament to the power of the dB-12 driver, and the extreme rigidity and strength of the cylinder enclosure.

Regardless, I would not view the lack of reactive force cancellation as a design flaw or a negative aspect of the sub; all single driver (and even dual driver mounted in the same plane) subwoofers will exhibit this characteristic to some extent.
Ed Mullen
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"What we do in life, echoes in eternity."


#7 of 30 OFFLINE   Wayne Ernst

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Posted April 12 2004 - 06:49 AM

Jesse,

Did you have the Martin Logan in the same room with the same audio source as you did with the SVS? If you were to take the Martin Logan home and run the test where you did with your SVS sub, I'll be the M.L. might also topple the coin too.
"My reality check ... just bounced"

#8 of 30 OFFLINE   steve nn

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Posted April 12 2004 - 06:56 AM

Ok! Then SVS passes the test then. Put a 50 lb sack of grain on top of it jesse and see if it will knock it off also? I predict it wont. Don't block the ports though.

#9 of 30 OFFLINE   Jesse Sharrow

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Posted April 12 2004 - 11:01 AM

OH MY GOD! Everyone listen! I love my SVS! I didnt like the martin logan as much as it.

Do I need to spell it out? LOL!

#10 of 30 OFFLINE   Robb Roy

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Posted April 12 2004 - 03:06 PM

Hmmm... I have never heard of said test until now. So I put a nickel on the edge of my PB2-Ultra earlier tonight. I've been playing music with 105+ DB uncorrected bass peaks, and that nickel hasn't moved one bit. I managed to drive my wife out of the house, but the nickel hasn't budged (although she did admit it was funny that a nickel could sit on its edge on the sub and not move). I'm inclined to leave it there until a cat or a movie knocks it down.

Somehow, I doubt the nickel makes my sub sound any better. Posted Image

-Robb

#11 of 30 OFFLINE   Chris A H

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Posted April 12 2004 - 06:44 PM

I am just so glad Jesse finally pulled the trigger! If there is hope for Jesse then there is hope for all!!

Posted Image Posted Image Posted Image Posted Image Posted Image

#12 of 30 OFFLINE   Edward J M

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Posted April 12 2004 - 11:47 PM

Robb - the PB2-Ultra is SUCH a rock solid piece. It feels milled out of a single piece of hardwood. Mine doesn't budge either, even at RL playback on a smooth laminate floor, and that's with just the stock feet! But it weighs damn near 200 pounds, too. Posted Image
Ed Mullen
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"What we do in life, echoes in eternity."


#13 of 30 OFFLINE   Michael R Price

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Posted April 13 2004 - 12:39 AM

Don't the large boxed SVS's have the drivers mounted on opposing ends to cancel 2nd order distortion? (And enclosure vibrations, too.)

#14 of 30 OFFLINE   ScottCarr

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Posted April 13 2004 - 12:45 AM

Michael

The PB2 line has 2 down firing drivers. I believe the B4 is the only one that has oppossing drivers

#15 of 30 OFFLINE   Chu Gai

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Posted April 13 2004 - 04:35 AM

I don't believe such an arrangement would cancel distortion Michael.

#16 of 30 OFFLINE   Bill Blank

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Posted April 13 2004 - 04:42 AM

I have to stop reading posts on SVS subs until I'm closer to pulling the trigger!

Jesse,

Does that Metallica DVD-A kick arse all the way through? I've been looking for some new hi-rez to pick up.

Bill

#17 of 30 OFFLINE   Edward J M

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Posted April 13 2004 - 04:45 AM

Simply mounting drivers in an opposing fashion to help cancel reactive forces might not reduce distortion (somebody should check on this just as an FYI), but a true push-pull configuration will.

The B4 has two drivers that fire into the cabinet on the forward stroke, and two drivers that fire out of the cabinet on the forward stroke. This cancels reactive forces and also reduces even order harmonic distortion.

M&K is a noted user of the push pull method.
Ed Mullen
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SVS

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"What we do in life, echoes in eternity."


#18 of 30 OFFLINE   Chu Gai

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Posted April 13 2004 - 05:17 AM

In a push-pull configuration, the elimination of distortion depends upon whether the device obeys a square law non-linearity. However speaker drivers don't obey this law and the mathematics that describe their behavior is more complex. If we assume that the two drivers are identical (now that's not something you're going to find in the real world at all) and have identical nonlinearities, then a push-pull configuration changes the nature of the nonlinearity from a nonsymmetric to a symmetric. I'd like to think that competent speaker manufacturers use good drivers, good cabinets with good bracing to achieve relatively low amounts of distortion.

#19 of 30 OFFLINE   Shane Martin

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Posted April 13 2004 - 05:47 AM

Quote:
I'd like to think that competent speaker manufacturers use good drivers, good cabinets with good bracing to achieve relatively low amounts of distortion
This is true of M&K but I haven't heard the B4+ to confirm that about SVS. Given the intense weight of the b4+ I'm pretty confident that they are able to achieve extremely low amounts of distortion.

#20 of 30 OFFLINE   Chu Gai

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Posted April 13 2004 - 05:59 AM

They seem very good at hitting the nail on the head.