Ultra driver vs. Plus driver text... (1 Viewer)

[Tom Vodhanel]

Out of respect for ACi...so that thread can get back on topic...I'm copy/pasting a post I made about these two drivers on HTF on 1-6-04.

If anyone has any legitimate questions, now is the time and this is the thread.

Tom V.
SVS
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Hi all,


First, remember that terms like “fast”, “tight” ,”musical” are subjective in nature. So by definition, what audio enthusiast A thinks is "fast/tight/musical"...audio enthusiast B may not. Also, human bias will enter into the equation at some point. for example, If a manufacturer goes into great detail about how “fast” their bass is...after reading enough about that...some folks will naturally have a predisposition to believe it. So when they get the product home...by god the bass IS fast.. (this is the same human workings that cause us to hear differences when painting the edge of your CD green---well, the website explained it in 5 pages with big words and they have a bunch of testimonials...so...)

When talking about "fast bass", a subwoofer reviewer once said to me..."oh yeah, the bass was so fast it got out of the room before I could measure it".

It is also important to consider the length of sound waves in this context and how that relates to their decay in a typical room. A 20hz sound wave is about 55ft long. The longer the sound wave, the more time it is going to take to decay. This longer decay time is often interpreted as “slow bass” simply because the bass doesn't *snap* to a sudden stop(as it may with a subwoofer that rolls off in the 35-50hz range). It isn't a coincidence that the majority of subwoofers that claim to be “tight/musical” are small/moderate sized sealed designs. If you look for objective performance data on these units, you'll notice there is one definite trend...they all tend to have a frequency response which rolls off in the 32-50hz range. Tom Nousaine has a lot of good FR data on a ton of subwoofers. Audio magazine and Audio Ideas Guide both used to have a lot of FR data in all their subwoofer reviews too. (AIG might still, haven't had time to pick up a copy for a few months).

Now, there is nothing wrong in preferring that type of sound...it is a personal preference after all. But the correlation between what you think is “fast/tight” often has little to do with any magic a given manufacturer knows...and more to do with the very basics of the units performance...the frequency response(and several other factors introduced below).

In the words of Bill Cosby, (paraphrased)"I told you that...so I can tell you this"...


Among SVS designs, the Ultra driver is definitely top dog. I'm not going to wax poetically about its design...it is just a very good unit(and very expensive). The dB12 (Plus driver) is also a very good design, just not up to the same standards. The same can be said for the ISD driver we use in the PCi/CS,PB-1 and PB-2isd subwoofers. At low volume levels, all three of these units are going to sound nearly identical...only as the volume levels increase will the qualities of the dB12 and then the Ultra driver manifest themselves into audible benefits. Just how MUCH the volume levels would need to increase depends on many variables...and just how audible the differences were...would depend on additional variables...including the listeners experience and insight into how these difference may present themselves during source material playback. Here is an example of how THD (total harmonic distortion) may present itself…

Let’s use 25hz and 90/95/100/105/110dB levels (just an example remember…)

The Ultra driver may produce

 

[frank manrique]

Hi, Tom!

Incredibly great stuff!

If only subjectivists (and certain objectivists too!) were to take this treasure trove of information to heart...just imagine the possibilities!.

Keep up the good work...

-THTS

"...hi, my name is Frank...and am an SVS bassaholic..."

 

[ErichH]

Thank you Tom

It's twue! It's Twue!
We know

E

 

[Scott Goldsmith]

Thanks for the technical info Tom. I personally don't care what the "technical aspects" of them are, I just know the Ultra driver is better, capable of more, etc, and that's why I ordered it. Some people just get too caught up in the technicalities of things Don't let them bug you

 

[Craig Chase]

Scott... Not trying to flame here... But what I had asked Tom was why Edward J M, Robb Roy, Paul Carleton and several others hear a difference at levels that won't even tax the ISD driver.

This was their TOTALLY subjective take on the Ultra driver... and noone has answered that yet...

 

[Robb Roy]

I wouldn't rule out number 5, either (at least in my case -- those other guys are much more experienced and smarter than I). I also biwired my mains and center and heard a difference, but can't tell you for certain it wasn't psychoacoustic. Never underestimate the power of cognitive dissonance... The difference I heard at lower volumes was extremely subtle, and it's been a while since I heard my old 20-39PC+, and we all know how bad auditory memory is. I don't remember exactly how I tried to describe the difference I heard, but I think I included form factor, EQ, and psychoacoustics as possibilities beyond just the driver.

I will be getting a PB10, so I can try to compare those at lower volumes to "see" what I hear, but that's not the "apples-ultra" to "apples-plus" comparison discussed here.

What I think would be interesting is your own blind listening impressions between a PC-Ultra and a 20-39PC+ at moderate levels.

-Robb

 

[Scott Goldsmith]

No flame taken, I read that other thread, long as hell, but read it. I don't fully understand all that in depth technical info on what makes a driver sound different than another, I would tend to bet the avg Joe thinks the Ultra sub sounds different because they paid for it.

I have never heard the Ultra, I have heard the PC+ and the ISD drivers, I couldn't really tell too much difference, I had one PC+ and 2 ISD's, so it isn't a fair comparison, both rocked and I didn't think about the sound difference.

I am sure the Ultra will play louder in the lower frequencies, so it may "sound" different because it's louder or you can hear it more, who knows.

But I just think some care too much about certain things and get bent out of shape/heated about them Not me though I love all bass, regardless of who makes it, etc No flame intented to those that care too much, I wish I knew enough to get bent out of shape or debate about it

 

[Craig Chase]

Hmmmmm... At normal levels, #'s 1, 2, and three won't matter... #4 COULD make a pretty big difference... and #5 ... errrrrrrrrr... ummmmmmmm... not good...

I DO agree with the idea that "I just like it better, because it sounds better to me"...

That being said... Some well respected SVS fans (remember, I own a B4+) have chided others for saying the same thing.... their preference for something in a subwoofer that was not measureable.

 

[Scott Goldsmith]

When you say chided are you saying they were bashed for saying they "heard" a difference and couldn't measure it? Do all audible differences have to be measurable? The difference between Polk speakers and Klipsch speakers are audibly different, but what measurement needs to be shown to let people know that?

That may sound stupid, but I don't claim to be very smart about techical in depth crap I just know what I like and would recommend.

 

[Craig Chase]

Scott... Yes... They were chided (bashed was likely too strong a word) for saying, for example, that a "Brand X" sub sounded better than an SVS because of subjective differences.

I have been on the receiving end of such chiding... and this from a blind test.

 

[steve nn]

When I had the PC-Ultra in the house I definitely could tell the difference between the TV-12 and the dB-12 driver. Of course much of that can be attributed to the different tunes presented in the PC-Ultra versus the 25-31CS+. I feel there is more to it though.

Soon I'll have the PB2-U (stock 25Hz tune) and the 10-ISD (20Hz tune??) which will make me more confident of what I think I think.

 

[Scott Goldsmith]

That's kind of weird, someone's opinion is always different than someone elses opinion. Not everyone likes the sound of certain things, like some people actually like Bose speakers Some don't like Klipsch, some don't like Paradigm, etc, it's all a matter of personal taste, if someone likes a certain sub more than another, who cares. Why should someone get bashed for it. Some people don't like loud bass, just subtle bass here and there, I love a lot of bass, I want to hear it all and feel it all, that's why I byu SVS subs, they satisfy my taste, is that bad?

Am I reading this correct or am I totally off track here?

 

[Craig Chase]

Scott... You are perfectly fine... no prob.

And yes, It is interesting to get more reports from those who hear a difference in the Ultra driver at lower levels...

 

[Scott Goldsmith]

Good, just didn't want to sound like I was rambling and not making any sense or not even on the right subject.

As for the low level difference, is the Ultra more sensitive than the db12 driver? If so it may be just that it reponds better at the low levels than the db12 driver. Is that was people mean by frequency response? Please ignore my stupidity, I really want to learn as much as I can so I can understand what people are debating about.

By the way, I keep forgetting to tell you, if you get bored of that B4+, there's always a warm spot on my carpet for it I love that sub, it has to be amazing to listen to!

 

[Craig Chase]

The B4+ is quite the machine... I have not heard anything that energizes a room like it....

 

[Geoff L]

We "all" don't hear the same nor like the same....
Add the oh so many other variables on top of that,,, and well..

Explains allot, would one not say.?

 

[Robb Roy]

Craig,

I am a big fan of what can be measured when it comes to subwoofers. I leave the possibility of what caused the difference in what I heard open – just because it wasn’t measured in my living room doesn’t mean it *can’t* be measured (including cognitive dissonance).

You’ll note I have never recommended an Ultra over the Plus based on the subtle and subjective difference I noticed between the two at lower volumes. If someone is bound and determined to have the best driver SVS has to offer, or if their listening environment, habits, and material call for it, then yes, I would recommend the Ultra driver over the plus, but not because of the subjective difference I experienced at lower volumes.

-Robb

 

[steve nn]

If someone is bound and determined to have the best driver SVS has to offer, or if their listening environment, habits, and material call for it, then yes, I would recommend the Ultra driver over the plus, but not because of the subjective difference I experienced at lower volumes.
__________________________________________________ _____

Well put Robb. I would agree with you.

 

[Craig Chase]

When I ordered the B4+, I was REALLY close to getting twin Ultras instead... SVS had an order cancelled on a B4+ (the guy changed the finish, so he still got the B4...) ... and offered me a great deal on the big boy...

But ya always wonder...

 

[Ned]

I spent the last 10 days comparing the 20-39CSi (mine), a 16-46CS Plus (borrowed), dual CS Ultra's (at a friend's), and dual Contrabasses (other friend's place). I'm still in the process of writing but I can tell you now there is a big difference as you move up the chain.