Comparison between the Hsu VTF-3 HO and the SVS PB12-Ultra

[Ilkka]

There's a whole bunch of other graphs that are important too, which are not being presented on this thread. I think a good place to look is the subwoofer shootouts at www.avtalk.co.uk and then Google the terms they use on those graphs.

I'm partial, but I would also suggest these two links for some graphs and explanations.

http://www.avforums.com/forums/showthread.php?t=247703

http://www.avforums.com/forums/showthread.php?t=259890

 

[Stone__Man]

thanks Josuah, and Ilkka for sharing the links. Peace

I don't feel I can ever have too many takes on this subject.

On with the comparo

 

[Eddie Horton]

I, too, would like to know why the graphs were taken with the mic in different spots for each sub. Especially, since the graphs were presented in a way that made me think the HSU graph was for a certain piece of program material at a given volume, and the next SVS graph was for the same piece of program material at the same volume. It's only natural to assume the mic is in the same place. Yeah, I know what happens when you assume, but otherwise the graphs of the two subs on the same material are meaningless. Maybe not meaningless, but certainly less meaningful. Not trying to ruffle any feathers, and etc.

 

[initech]

Ok, I'm failing to see what this is all about. Sure, there are some technical questions we might have in our heads. Yet, Craig is posting his thoughts and some graphs along the way. He said, I think, that he was going to listen for several weeks. So, I'm wondering why all the critics at this point. Its not like he's submitting this for an end all professional review.

Possibly there have been some valid points raised. Yet, I wouldn't lambaste someone until his final thoughts were posted. Then if I had questions, I think its fair to ask them and take him to task.

Also if someone is moronic enough to make a purchase before all the results are in, well I'm not sure if any differences would really matter.

as an aside, mac murray makes a mean 2002 pinot...

 

[jakeman]

I, too, would like to know why the graphs were taken with the mic in different spots for each sub. Especially, since the graphs were presented in a way that made me think the HSU graph was for a certain piece of program material at a given volume, and the next SVS graph was for the same piece of program material at the same volume. It's only natural to assume the mic is in the same place. Yeah, I know what happens when you assume, but otherwise the graphs of the two subs on the same material are meaningless. Maybe not meaningless, but certainly less meaningful. Not trying to ruffle any feathers, and etc.

Hi Eddie,

Methinks you and others are continuing to read far too much from these imprecise rough graphs. To me they were nothing more than unique plots of Craigs particular room. Your room would show different looking curves. Remember they were done in an HT basement room whose dimensions are going to produce some large nodes which will be excited or diminished by each subs distinctive anechoic FR, the direction of the driver/ports, and the placement of the mic. In that regard a difference of a couple of inches will alter the shape of the graph so don't get so hung up on the graphs. Craig has stated many times that the "optimum" test will be done when weather permits and as such I was surprised anyone tried to read much into the graphs. Try to see through the malicious attempt by one poster to distract everyone from the excellent work Craig has done here.

John Johnson dealt with the problems associated with in-room testing very well by using a large room and close mic placement to minimize room resonances. He also used instruments which attempted to adjust for the time delay of room echo. Perhaps some graphs a la Johnson with mic placement 1 metre or 12" from the Ultra driver or ports would be interesting and would make an good though still imperfect comparison with the review graphs while we wait for the outdoor tests. Even then expect some imprecision because of the different port/driver configurations and Craig's room. Bottom line: the measurements are too imprecise to get overly concerned or draw conclusions. That's why the subjective impressions are far more informative. If you want the best graph of performance so far its still this one and its a mighty fine looking linear curve considering it was done indoors.

 

[bossobass]

Ilkka,

"And remember that we know what Ultra's GP response looks like, it's already boosted in 20-60 Hz range."

Actually, I always thought of it as being flat from 20-40Hz, then dropping like a rock to 80Hz.

Looking at your overlay of HO and Ultra, I see only this (keeping in mind they are in-room casual graphs, as I did when they were first posted):

15-50Hz, Hsu graph varies 9dB, SVS graph varies 11.5dB
20-80Hz, Hsu varies 13dB, SVS varies 13.5dB

Given that the Ultra is known to have an 8dB or so variance at 2M, GP from 20-80Hz, most of that being from 40-80Hz, and not knowing the Ho's 2M, GP FR performance, I really fail to see the big deal.

I believe that if you had simply asked the question that you would have received the answer...no big deal. If you had asked politely for a certain measurement, Craig would have obliged, but wait your turn...we all have dumb little requests, and mine was before yours.

Craig is having fun with a new model subwoofer, the way he enjoys the process, which is usually a few weeks or so. I enjoy reading along and being part of the fun.

Have a seat. Relax. Have a good time.

Bosso

 

[craigsub]

Here is the disclaimer which I put at the top of the 3 in room graphs ...

Here are some in room sweeps using the QuickSweep function of TrueRTA. TrueRTA's Quicksweep takes a 1/24th octave sweep - then allows a smoothing to be applied. This is with 1/6th octave smoothing.

This is the type of response one usually gets with no eq ... in fact, most are worse.

I thought that got the point across that these measurements were not intended as a barometer for performance, but rather that they showed the diffilculty of getting a flat, in room response. Yes ? No ?

 

[jmprader]

...I thought that got the point across that these measurements were not intended as a barometer for performance, but rather that they showed the diffilculty of getting a flat, in room response. Yes ? No ?

From my responsive posts elsewhere, your words were never lost on me and I'm sure many others here have some basic understanding of the difficulty in getting a flat room response. Now that background noise levels have diminished, I for one am looking forward to some more opinion, insight and polite discourse.

 

[craigsub]

From my responsive posts elsewhere, your words were never lost on me and I'm sure many others here have some basic understanding of the difficulty in getting a flat room response. Now that background noise levels have diminished, I for one am looking forward to some more opinion, insight and polite discourse.

That would be a good thing ... polite discourse. I am leaving on a biz trip in about a half hour. I am hoping to get some more listening done Saturday, followed by some outdoor GP tests on Sunday.

For the outdoor tests, I am planning on using the SVS PB10-ISD as a "barometer", as Ed Mullen and Ilkka have already measured it.

By using it as a barometer, then also measuring a VTF-3HO, it will be pretty easy to make reasonable comparisons to its objective performance vs. all the other subwoofers each of those two have measured.

For example, we know that Ed measured the PB10 as delivering about 94 dB @ 20 Hz, and the PB12-Plus as delivering about 102 dB (I am doing this from memory - so if I am off by a dB or 2, let's not go Ilkka on me, ok ? ) ) ...

So ... If our PB-10 delivers 94 dB, and the VTF-3 HO delivers 99 dB @ 20 Hz (this is just speculation, so please do not post this later saying that "HEY, YOU SAID IT WOULD DO 99 DB ... NOW YOU SAY 101 DB. YOU SHOULD BE FLOGGED !!!!" ... ), it would be reasonable to say the Pb12-Plus is 3 dB stronger @ 20 Hz than is the HO...

Hopefully this makes sense to everyone. I really want a situation where people come away from this confident in the objective perfomance of the new VTF-3 HO.

PS ... "Go Ilkka on me" was for humor ... think "go Postal" ... this disclaimer was necessary to keep things fun.

 

[bobgpsr]

smoothing TrueRTA quick sweeps

To actually smooth to 1/6th octave using TrueRTA you save a normal 1/24 octave quick sweep to a memory and then pull down the "smooth" function off of the Utilities menu. It gives you the opportunity to also shift the smoothed result by 10 dB so you can see the before and after smoothing.

For example as measured with my DIY Tumult sub using a Quick Sweep normal 1/24th octave and also 1/6 octave smoothed (shifted up by 10 dB).

or just changing TrueRTA to 1/6 octave after a 1/24th octave sweep (which just samples the 1/6 octave points, interconnecting with straight lines):

notice how either smoothing or just setting 1/6th octave misses the 80 Hz room null and the dips at 52 and 57 Hz. These sweeps were done using a LinearX M31 calibration microphone in my unfinished basement.

Bob

 

[ssabripo]

boooooo!

Not even 80dB's out of a Tumult Bob???

hehehe....

 

[bobgpsr]

...Not even 80dB's out of a Tumult Bob???..

Sherv,

You know better. When I took those sweeps, I had just before set a actual 80 dB(c) SPL as measured by a Radio Shack SPL meter using pink noise. However I did not bother to calibrate TrueRTA for the absolute level. I've noticed that TrueRTA's quick sweeps seem to be at a 25 dB higher level than its pink noise levels. A comparision can be seen here:
http://www.avsforum.com/avs-vb/showthread.php?p=7378838&&#post7378838

I've yet to try to find the actual just under compression level of my DIY sub. Sill working to minimize air leaks. But this is getting off topic......

Bob

 

[ssabripo]

hehe....just busting your chops Bob! it's all fun and games...you doing good.

I wouldn't even dare mess with TUmults! I'm actually planning on getting one or two in a sealed configuration....I may ask for some do's/dont's from ya!

 

[steve nn]

I'm actually planning on getting one or two in a sealed configuration....I may ask for some do's/dont's from ya!
Today 01:31 PM

What type of bass license do you carry sherv. You do have to try it out though...with the use of LT or the mono BASSIS, you'll be impressed I guarantee.

 

[ssabripo]

What type of bass license do you carry sherv. You do have to try it out though...with the use of LT or the mono BASSIS, you'll be impressed I guarantee.

well....first things first...I gotta work on the wife approval this summer. Hmmmm, maybe a nice trip somewhere or a piece of jewelry or something

 

[steve nn]

well....first things first...I gotta work on the wife approval this summer. Hmmmm, maybe a nice trip somewhere or a piece of jewelry or something

I got that all figured out for you Sherv..this is what you do. Pull your driver out of your vented you just built (down the road) and put it in a sealed design! Store the vented enclosure out in the garage and swap back and forth as your desires dictate. In time you could feasibly have three, four..eight enclosures stored out in the garage on their own special shelf. Huh? A new driver now and then wouldnt hurt for variety though.

 

[jimsfield]

Going Ilkka? You gotta love how language evolves, especially on the Net.

 

[Ajax]

I think it should made a rule that, when Craig does these comparisons, he's not allowed to go on business's trips or spend time with his family. I mean, REALLY! How could those things be more important than us?

 

[craigsub]

OF course, Nothing is more important than subwoofers ... Jack, I apologize to you and everyone else for leaving.

My wife, upon hearing that I would be home tonight, ran out and got King Kong ... It will be family movie night at the Chase Ranch.

As for these two subs - about halfway through this, and there is no clear cut leader. They are both excellent performers.

Hopefully, we can now continue, and keep it friendly.

 

[Ajax]

I'll be curious to hear what you think of "Kong."

"Amen" to the "keeping it friendly" thing.