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SVS PB2-Ultra Test & Review (1 Viewer)

Edward J M

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Sep 22, 2002
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Actually, the platform under the PB2-Ultra has 4 heavy duty caster wheels. I had a few guys over practicing archery in the back yard, and they helped load it onto the platform.

I cinched the PB2-Ultra baseplate to the platform with a tie down to keep it from sliding, and we were off to the ground plane races, looking for all the world like kids dragging a very expensive toy box around on a wagon. ;)

Weather was just perfect that day - no wind and low 70's with sun and low humidity. And I'm happy to report the PB2-Ultra survived the experience with nary a scratch, and was utterly unfazed by my endless requests to belt out FR sweeps and sine waves at ridiculously high volumes.
:emoji_thumbsup:
 

Zack_R

Stunt Coordinator
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Nov 4, 2002
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Great review Ed! I enjoyed the compression analysis. Nice addition!

Having owned a CS Ultra for 1.5 years it is great to see some more objective testing of the TV-12 driver. To date, I have been able to gradually increase the spl of a given movie passage to a point in which the amp clips before the CSU ceases to increase it's output (per the rat shack). This is one of the reasons I liked the compression analysis.

Sounds like you are as thrilled with the way the driver sounds and performs in the gorgeous box enclosure as I am with spartan 2039 enclosure.

A few questions (Sorry in advance for some of the "if this then that" type of questions I'm asking)

1) In your THD testing did your ears detect a noticeable difference when the sub is playing at say 8% distortion versus 4% for a given frequency?

2) Do you think 10% THD is an acceptable maximum limit or should it be higher or lower than 10%? For that matter is there an audible difference between a sub that produces 2% distortion versus 1%?

3) Was the PB2U set in the 25 hz or 20 hz mode for the 20hz measurement @ 1 meter?

Since the ground plane measurements are so close in output between the 25 hz setting and the 20 hz setting when playing a 20 hz sine wave, I'd be tempted to run the PB2U in the 25 hz tune with the low pass filter disabled for both movies and music.

With the Ultra in this setting, I'm thinking the scene from Pearl Harbor would have netted about the same spl as the 20 hz setting.

FWIW, I obtained about the same differences in dB during a mild frequency sweep when plugging one port of the CSU for a 16 hz tune versus the stock tune.

I suspect if you had run a 27 hz or 28 hz test tone that the differences between the two tunes would be close to four dbs for that frequency. In the 16 hz tune my CSU is down about 4 dbs at 23 hz. Otherwise my observations mimics your max curve very close albeit at a lower tune.

4) I'm curious during the ground plane measurements if the microphone was placed 2 meters on the side that the ports face if you would have obtained a higher spl for the frequencies that mostly come from the ports?

5) Is there a way to quantify the sound difference you are hearing between the TV-12 and the dB12 (or any woofer)? I think the technology difference explains some of the sound differences when played at very loud volumes but what about the differences you are hearing in the more subdued volumes?

Thanks again for the great read and awesome review!
 

Steven_E_S

Auditioning
Joined
May 1, 2004
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14
This is the review I've been waiting for. My PB2 Ultra is being delivered this Wednesday. GREAT REVIEW. Only problem I have now is Bax Global says it will be delivered between 8 & 5 so a day off adds almost $200 to the cost. Sheesh money, money and mo money. hehehe
Steve
 

Robb Roy

Supporting Actor
Joined
Jul 15, 2002
Messages
711
Ed,



I haven't been ignoring you. I’ve wanted to write something about this beautiful piece of gear for some time, but the words fail me. It is so good that every time I try to describe it, I sound like a cheesy reviewer from one of the less useful audio rags. I will eventually say more once I get past the writer’s block.

The one easy thing to talk about is the appearance. I have never seen a digital photo that comes close to doing the craftsmanship of the SVS PB2-Ultra justice. If you were to purchase some kind of hand crafted, American made chest with this kind of quality, you could expect to pay what this sub costs. It is such a stunning piece of furniture, that when I look at it, I can’t help but think the fact it makes sound at all is a bonus. When company comes to visit, someone invariably remarks about what a gorgeous piece of furniture it is, and then asks what it is.

The sound is harder for me to describe because it’s just “there”. For music, everything just sounds like it should – every note from a bass, or drums, or organ sounds like the musician is in the room. It’s so natural you forget it’s there unless you go out of your way to pay attention to just the sub. For the most part, the same can be said for movies – special effects sound more life-like. When infrasonic material is reproduced, it fills and moves the room, and its occupants. This is one of those places that gets hard to describe without silly “rips through you”, “makes you worry about the structural integrity of your home”, “punches you in the gut”, etc. explanations. At any volumes I would dare listen, there is absolutely no port noise or audible distortion.

Compared to other subs? The only sub I’ve owned that comes close is the SVS 20-39PC+. I know that whatever I throw at this thing, the PB2-Ultra will reproduce it accurately at any volumes I would dare to listen, with absolutely no worries about whether or not the sub is missing something (or going to bottom out). The biggest difference between the SVS PB2-Ultra and every other piece of gear I’ve ever purchased? I have absolutely no desire to upgrade it.

-Robb
 

Wayne Ernst

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Feb 24, 2002
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Very nice work on the review, Ed. Needless to say, the content was nearly too much too read in one sitting. Fortunately, we have book marks. :)

Thanks again.
 

George_W_K

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Ed,


Stellar review. Way to go all out and provide such a thorough review. This, of course, means I hate you. It is my goal to one day own the TV-12 drivers, and then you've got to let me know how great they are!!! :D

Well, I'll enjoy the hell outta my PB2+ in the meantime. :) :)
 

Robb Roy

Supporting Actor
Joined
Jul 15, 2002
Messages
711


Hey, Ed got Bax to bring it into the house, and friends to help him with the outdoor testing. I had to drag the thing from the garage, through a narrow hallway, and into position by myself.

Since it's germane to this thread, here is the page where I put the pics of the PB2-ultra's arrival:

http://www.robbroy.net/HT/PB2-UltraArrival.cfm

-Robb

EDIT: I'm a lousy photographer with a cheap camera.
 

Robb Roy

Supporting Actor
Joined
Jul 15, 2002
Messages
711
Keith,

Thanks!



I remember when the PB2+ was announced I got excited. I literally thought to myself, however, that it wouldn't be worth upgrading from the 20-39PC+ unless I could get an SS series type of finish and Ultra drivers. Good things come to those who wait.

-Robb
 

Richard_M

Second Unit
Joined
Feb 8, 2001
Messages
265
Ed...

Fantastic and very thorough review.

If I need a new sub I know which one I would be looking at to purchase.

Makes for excellent reading, look forward to more in the future.

Dick
 

Edward J M

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Sep 22, 2002
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Hi Zack:

I knew you would be good for some excellent questions!


My theory (which could be bunk, of course) is that the motor strength (the BL product) is exceptionally high on the TV-12. The strontium ferrite magnets have an extremely high field strength (B), and the 10 layer flat wound voice coil also has a very high field strength (L) when an alternating current is passed through it. A high motor strength (BL) means good cone control. Also, the lower the inductance of the VC, the faster it can respond to changes in applied voltage, and the better the impulse response curve will be. SVS does not publish the inductance of the TV-12 VC (or any of its T/S parameters) because they are easily misunderstood and also are considered proprietary. Nevertheless, I would imagine the combination of a high motor strength and a low VC inductance are primarily responsible for the way the TV-12 driver sounds, even at low volumes.

Ed


http://www.adireaudio.com/Files/Tec...WooferSpeed.pdf
 

Edward J M

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Sep 22, 2002
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Steve, Dick, Wayne, George - thank you all for the kind words. George, the PB2+ is one hella subwoofer and you should enjoy the heck out of it.

It IS a long report, Wayne; I'm glad you took the time to read through it all, and used the bookmarks. There are many things that were pared down as it were. I'm considering hot-linking certain things (like equipment descriptions and generic explanations of testing and performance concepts) to my website to make future reports even more succinct while still including all the test data.

Robb - that was an awesome explanation. Time and again I find myself getting lost in the music, instead of focusing on the subwoofer; I suppose that is the greatest compliment one could pay to a subwoofer in a music application.

Enthusiasts try so hard to describe why a sub sounds a certain way - musical, lively, buttery transients, transparent, etc. And speaker designers try so hard to develop objective measurements to explain why. Sometimes I think neither group is completely successful. ;)

I do think a nice-looking FR transition from the speakers to the sub is probably one of the most underrated aspects of achieving good sounding bass. ANY sub can be made to sound rotten if it is poorly set-up and the room has bad acoustics.

Jack - again, coming from you that is a huge compliment. When I read about Yates' test methods, and saw that respected designers like Tom Vodhanel and Mark Seaton spoke so highly of them (and the fact that Tom V exclusively tests at 2M ground plane), I felt obligated to adopt similar test methods where ever possible. Imitation is the sincerest form of flattery, I suppose. :)

I got so wrapped up in that fascinating Adire tech bulletin on woofer speed, I forgot to hotlink it, and I have done so above, despite your inclusion of the same in your post.

It was really cool to see how adding mass to the woofer cone did not affect its impulse response, but adding inductance to the VC did. It appears (at least from this tech bulletin) that the faster a VC can shed stored current, the faster it can react to changes in voltage, and the more accurately it will track the constantly varying input signal. Is this the definitive explanation of transient response? I don't know, but the impulse response vs. inductance vs. mass curves are certainly worth a hard look.

Ed
 

Mark Seaton

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Mark Seaton
Ed wrote:


Nope, this is only the determinant of the rise of the transient. The phase response and low frequency response dictates the nature by which the impulse settles.

Hope this helps,

PS-great work on the review and measurements.
 

Mark Seaton

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Mark Seaton
Ed wrote:


Nope, this is only the determinant of the rise of the transient. The phase response and low frequency response dictates the nature by which the impulse settles.

Hope this helps,

PS-great work on the review and measurements.
 

Craig Chase

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In case noone noticed... Mark Seaton had his Contrabass subwoofer tested by Ultimate A/V ... where objectively it was among the top subwoofers tested. It delivered roughly 115 dB outside... at 20 Hz/one meter... Impressive performance, to say the least.

Ed, you just got Kudos from Mark, deservedly so, for your review.

That makes you one of the "big boys"...
 

Craig Chase

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Craig
In case noone noticed... Mark Seaton had his Contrabass subwoofer tested by Ultimate A/V ... where objectively it was among the top subwoofers tested. It delivered roughly 115 dB outside... at 20 Hz/one meter... Impressive performance, to say the least.

Ed, you just got Kudos from Mark, deservedly so, for your review.

That makes you one of the "big boys"...
 

Edward J M

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Joined
Sep 22, 2002
Messages
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Thanks, Mark! This is pretty heady stuff......let me see if I've got this straight.

1) The mass of the cone affects the sensitivity, but not the frequency response.

2) Inductance affects the upper frequency response, but inductance only has to be low enough to not affect the FR within the normal operating bandwidth of the subwoofer. Since the TV-12 maintains a flat response out to beyond 200 Hz, that would certainly seem sufficient for nearly any application.

3) Impulse response cannot be attributed to a single factor, but is affected by a combination of variables like inductance, phase response, and low frequency response.


Hmm...perhaps this issue speaks to the heart of why the TV-12 driver sounds so darn good - a high motor strength that remains linear (BL vs. excursion), and a well-designed suspension?

Also, what does "loading linearity" refer to?

Sorry for the 20 questions, TIA. And thank you for the compliments; your's and Tom's posts about the ongoing Yates review, power compression, and outdoor testing were largely responsible for the test methodology I used in this review.

Ed
 

Edward J M

Senior HTF Member
Joined
Sep 22, 2002
Messages
2,031
Thanks, Mark! This is pretty heady stuff......let me see if I've got this straight.

1) The mass of the cone affects the sensitivity, but not the frequency response.

2) Inductance affects the upper frequency response, but inductance only has to be low enough to not affect the FR within the normal operating bandwidth of the subwoofer. Since the TV-12 maintains a flat response out to beyond 200 Hz, that would certainly seem sufficient for nearly any application.

3) Impulse response cannot be attributed to a single factor, but is affected by a combination of variables like inductance, phase response, and low frequency response.


Hmm...perhaps this issue speaks to the heart of why the TV-12 driver sounds so darn good - a high motor strength that remains linear (BL vs. excursion), and a well-designed suspension?

Also, what does "loading linearity" refer to?

Sorry for the 20 questions, TIA. And thank you for the compliments; your's and Tom's posts about the ongoing Yates review, power compression, and outdoor testing were largely responsible for the test methodology I used in this review.

Ed
 

Matthew Todd

Second Unit
Joined
Jan 3, 2000
Messages
338

I was planning on putting a B4+ in my dedicated theater room when I get it finished, but now I'm wondering what about using 2 PB 2 Ultras instead. Cost wise, it would be more to go for the 2 Ultras ($3500 for a B4+ and K1 vs $4800 for 2 PB2 Ultras).

What are your thoughts on this?

Matt
 

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