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HSU VTF3R or SVS PB2 ISD (1 Viewer)

CurtisSC

Screenwriter
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Jan 28, 2003
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Geez Rob....took you this long to pipe in? Were you having fun reading the thread? I know a lot of others have.
 

Tom Vodhanel

Senior HTF Member
Joined
Sep 4, 1998
Messages
2,241
Hi Guys,

I just received an email asking me when HF reviewed a 16-46PC+? I had no idea what he was talking about...but he linked this thread and now I see how it could be confusing. Just to clarify for everyone to avoid further misunderstandings and the inevitable emails I'd get as a result...


Howard Ferstler has only reviewed the old ( about 3 generations old now) 16-46PC and the 25-31PCi. His quote of the 16-46PC being $850(which caused the confusion since the 16-46PC+ is $875) is as dated as the SVS he reviewed. The 16-46PCi is $649. The updates include (but aren't limited too) the new ISD 12" driver and the new BASH amp. If anyone is interested in the performance differences between the older cs/pc driver and the new ISD a quick search on this forum and others will turn up a ton of user feedback from guys who have upgraded their SVS. The new BASH amp is very important for primarily two regards...it is much more powerful (190w vs a FTC confirmed >300w for the BASH) and we were able to customize the EQing of the BASH amps exactly to our needs. We weren't able to do that with the older *rcm* style amps. The end result is a much flatter freq-response. Hopefully we'll be able to convince HF to review another SVS soon...maybe as part of a big subwoofer shootout?..:)


Tom V.
SVS
 

Zack_R

Stunt Coordinator
Joined
Nov 4, 2002
Messages
220
Having tested my SVS Ultra and BIC America Sub and my Main speakers set to large (subs off), I was very suprised at how close the 1/12 per octave graphs were between all three, to a certain point.

The BIC is a 12" front firing woofer with 2 three inch ports tuned to around 30 Hz. My mains are acoustic suspension Sansuis with 15 inch woofers and the Ultra is a 12 inch driver in the 2039 enclosure. Both the Ultra and the BIC are passive but for this test I powered both with one channel of the Samson 1000 or 500 watts.

In my bumpy room the BIC and SVS had the closest curves down to around 30 where BIC rolled off and the Ultra chugged on to ~16. My Mains ran out of gas around the 38-40 Hz range although the graph sort of hid that because the sound was heading into a null.

This test was performed at 85db ~15 feet from the subs / speakers. So I'm ASSUMING that neither product was outputting any measurable distortion.

However,and its a very BIG HOWEVER. When I played many musical selections in the same db range as the 1/12 octave test (85DB) and choosing selections that didn't go below 30 Hz the Ultra was head and shoulders above the rest.

Certain rap music I played that contained slow and deep bass, the BIC and Ultra were on par. But if you were to play most any hip hop or metal selection the Ultra was much better at articulating multiple bass notes where the BIC sort of blurred the bass. I mean you could hear the bass drums and bass gutiar but it was a little *out of focus* as compared to the Ultra.

I think most speakers can handle a single tone within their limits pretty accurately. But when you play music you are now throwing multiple bass frequencies at a woofer and some woofers just do a better job than others at reproducing multiple bass frequecnies at varying spls. It could also be a combination of cabinet, ports, etc.

I also think when playing music, that this is when THD that would not be present on test tones could be present with music at the same db level. This, to me, is why I think some prefer certain woofers over another even though there is no quantifiable proof that one speaker would be that much better than the other (based on graphs). If you get into high spl graphing, such as Brian Weatherhead did in his 2001 review, the limitation of a sub will probably surface.

In my situation, I was able to quantify the difference I was hearing with the Avia subwoofer calibration test and the spl meter. When you perform this test, Avia plays a portion of the frequecny range from 35-70. It meanders around so to speak. Remember my room has a bumpy response for all speakers tested. Well when it was the BIC's turn, the SPL meter hardly budged as the bass for the sub woofer pink noise played. It was if the woofer could not respond fast enough to the changing input signal. As well you could not hear much of a differnce either (C-Weighted slow) When it was the Ultas turn you could hear and consequently see the SPL meter swing to the changing bass pitch during the pink noise.

I did this test months ago but I'm planning on retesting because I have since found a location about 13' from the sub that gives a much smoother response curve. I'm hoping this smoothness may show a subs weakness as there are fewere nulls that can hide a poor response. I'm not optimistic that it will though because I think the real test is with multiple bass notes, such as music.

So after writing all that, I think when you start comparing two high caliber subs such as the HSU and SVS PC+, even the little Avia needle swing test may not offer much aid in quantifying the results. Then you are left with a subjective impression unless you can somehow check for distortion while the music is playing.
 

Rick Hilst

Grip
Joined
Oct 26, 2003
Messages
16
I think an objective comparison can be made between subs if (1) the tests are performed using a consistent scientific basis and (2) the tests are performed by someone who has no bias going in. I think if either of these are not true, then the results are likely to be biased, maybe not even intentionally.

I think where there is a significant difference (e.g., one sub trailing off at 30 Hz and the other sub going down to 16 Hz) between subs, even a non-scientific comparison will obviously identify clear-cut differences. When the subs are much closer in capabilities, I think that a more scientific and unbiased approach is required to determine which one is "better".

Part of any scientific analysis would have to include an identification of the variables to be measured, how to compare those variables and what weight to assign each of those variables. Getting agreement on what these variables are and how to measure and weigh them is likely to be an argumentative process. For example, sheer loudness (max dB) seems to be greatly emphasized in many of these forums and therefore seemingly would be a variable that should get a heavy weighting. However, my personal opinion is that loudness is a relatively unimportant variable. I have no intention of playing a sub that gets anywhere near the 115+ dB levels that are bantered about in some postings. As long as a sub plays loud enough that I get the full HT experience (for me), anything more would be unimportant and of no additional value to me.

On the other hand I might rate the importance of a flat frequency response curve over some range (say 20-100Hz), minimal harmonic distortion and minimum overhang as more important factors. Someone else might put a heavy emphasis on a sub going to very low frequencies (~10 Hz).

The bottom line is that any analysis that is going to be acceptable to anybody other than those supporting the "winner" is going to have to be clearly done in a scientific fashion and done with everything agreed to and defined before the analysis is done. As far as I know, this type of comparison of subs has not been done. All the comparisons I have read have had an iffy scientific basis and a lot of subjective versus objective conclusions.
 

Edward J M

Senior HTF Member
Joined
Sep 22, 2002
Messages
2,031
Rick:

I invite you to partner with me and contribute to the development of the testing set-up and methodology.

If we do ground plane testing, this won't be terribly difficult, because about the only variable at that point will be mic placement.

The thing I see which needs to be ironed out is where to place the mic, as the two enclosures are radically different in configuration (long tube vs. box).

I'm thinking perhaps laying the SVS on its side (suitably supported at the top with a small block of wood to keep it level with the baseplate) so its woofer and ports are at the same height as the HSU.

If the woofer and ports aren't at the exact same height, we can place something under the HSU to make it so.

Then we can keep the mic at the same height and attitude and distance for each test run.

To make sure the relatively long distance between the SVS woofer and ports does not become an issue, I'm thinking a 2 meter distance for mic placement, as measured to the centerline of the woofer/ports.

As for testing, how does this sound (again shooting from the hip and subject to your input):

1) 1/24 octave frequency response sweeps at 95, 100, and 105 dB from 10-100 Hz in the following tunes:

SVS 20 Hz, 16 Hz
HSU 22 Hz, 18 Hz

2) THD analysis at 15 Hz, 20 Hz, 25 Hz, 30 Hz and 40 Hz at 95, 100, and 105 dB or until 10% is reached, whichever comes first.

For the 15 Hz test, the SVS will be run in the 16 Hz tune, and the HSU will be run in the 18 Hz tune.

For all other THD tests, the SVS will be run in the 20 Hz tune, and the HSU will be run in the 22 Hz tune.

How does that sound for starters?

Regards,

Ed
 

Paul_Ptaaty

Stunt Coordinator
Joined
Oct 16, 2003
Messages
77
Ed,

Looks like you have put up what looks to be a good test, and as "scientific" as we can hope for.

So are you going to be testing the VTF3 vs the 20-39 PC+?

It was noted that when the VTF3 is again available it will be slightly upgraded. Maybe the test should include the upgraded sub, just so there are no lingering doubts.

This should be a pretty interesting test! It would be nice to throw a PB2-ISD in the mix as well, as it should be more capable over 25 Hz, but who knows how close lower than that.
 

Edward J M

Senior HTF Member
Joined
Sep 22, 2002
Messages
2,031
Hi Paul:

Well I was thinking of trying to find a local VTF-3 since testing the latest version would mean buying one and reselling it, probably at a loss. I think buying one just to test it and return it is unfair to the company and underhanded and I won't do it.

Testing any PB2 ground plane would be a real chore and will require some friends with strong backs. I have a three level spinal fusion with more titanium parts bolted to my spine than the Terminator, so I won't be lifting/moving my PB2+ anytime soon. :b

Also weather will figure into this since I do live in upstate NY and inclement weather is right around the corner. Ground plane testing in the snow is out of the question. It might be neat to watch the ports blow snow around, but it wouldn't be fair to the electronics. ;)

Of course, any objective shoot-out will have repeatable data and witnesses/owners are welcome and there will be nice digi-pics showing the sub/mic configuration for each.

Details on the test rig specfics and calibration of same will be posted along with the shoot-out report so there will be no questions about the equipment or the validity of the data it generates.

Regardless, I'm committed to getting it done, one way or the other. Any upstate NY VTF-3 owners want to pony-up? Free unlimited beer (after the testing of course) and pizza is in the offing if you want to participate in the shoot-out.

Ed
 

CurtisSC

Screenwriter
Joined
Jan 28, 2003
Messages
1,412
Edward,

Give Hsu Research a call or drop them an email. That is what I did with Ron and told him my full intentions.

I'm with Paul and think the latest interation of each sub should be used, but I realize that may be difficult. I realize it may cause a sting to the credit cards, but maybe with some prodding from us, the companies may help out a bit.

With the new VTF-3's, from information on the Hsu forum it looks as though the latest interation will be downfiring, which should help with the placement issues that you mentioned earlier.

Regardless of the objective/subjective results, I'm just glad another SVS owner, such as yourself, will get a chance to hear a Hsu sub.
 

Edward J M

Senior HTF Member
Joined
Sep 22, 2002
Messages
2,031
Curtis - you've made some in-roads over there - can you break the ice for me?

Is there someone over at the HSU forum who might want to buy the latest generation VTF-3 after the shoot-out? No bottoming or audible distress will be allowed, and a strict 10% limit will be placed on THD, so the sub should be nicely broken in, but not abused, after the testing. I know it has been out of stock for a while, so there should be some takers?

Rick - are you pre-set on HSU, or are you going to be a hold-out for the test results? You strike me as the analytical sort, so I'm betting you'll want to see the numbers first? If not, maybe you would like to buy the HSU regardless of the outcome?

We can also do in-room testing to see the effect the room has on the subs (the software quick sweep has a long gate and allows room effects to fully develop, unlike the short gate MLS). That's always cool to see. You get boundary gain, room gain, and the room's acoustic "signature", replete with peaks/nulls.

With boundary gain, the amount of power needed to reach a given SPL will be considerably lower, so THD at a given should drop accordingly as compared to ground plane.

The nice thing about ground plane is that it removes the room effects completely, and really lets you see how the sub responds in a quasi anechoic environment. When a manufacturer claims (for example) 18-150 Hz +/- 1 dB, there is no way that can be verified if the room is included in the equation.

Rick - any thoughts yet on the testing methodology with respect to mic placement and sub orientation? Again, the objective with ported subs to the evenly split the distance between the woofer and the ports, and make sure the overall mic distance to the sub centerline is the same for each (I'm thinking 6 feet). I was also thinking of keeping the mic horizontal, at a height of about 20", directly facing the subwoofers.

Regards,

Ed
 

CurtisSC

Screenwriter
Joined
Jan 28, 2003
Messages
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Edward,

I will make a call over there and see what I can do.

May I also suggest throwing in a blind listening comparison as well?
 

Edward J M

Senior HTF Member
Joined
Sep 22, 2002
Messages
2,031
Thanks, Curtis! A double blind subjective evaluation will be possible only with helpers/owners/witnesses. We'll see where this thing goes.

As we discussed, a person can prefer the sound of a sub which actually measures inferior to a competitor. There is nothing wrong with that, but the choice to purchase should be made with that knowledge.

For example, some people actually prefer the sound of high THD at low frequencies. A 25 Hz tone with 50% THD will have a bunch of sound at 50 Hz and some at 75 Hz (and so on) and might sound "fuller" or "more complex" to some ears. And then there is the issue of mid/upper bass harmonics emphasis previously dicusssed in this thread.

Regardless of personal preference, the world of subwoofing is dominated with specs, numbers, and bench racing. It's all too easy to selectively quote outdated data, or deliberately mix test results from different methodologies (like MLS vs. ground plane vs. in-room) to make sub A seem far superior to sub B when in reality it is not true.

For example, Doc Johnson uses MLS and places his mic near the woofer cone. His FR curves have a unique signature to them, typically showing a peak around 50 Hz and a slow decline below that. This could be a function of the test method, and could also be a function of the fact that the woofer output itself will trail off as the frequency drops and the resonator (far from the mic with his method) takes over. A ground plane sweep of the same sub with the mic equidistant from the woofer and the ports will likely show a considerably different curve.

Is one test method worse than the other? Not really - as long as the tester remains consistent from sub to sub. The real differences between two subs can only be deciphered under identical test conditions using identical methodology. That is why Nousaine's data is so popular. Same room, same location, same mic distance, same THD-limited SPL testing.

Apples to apples.
 

Wayne Ernst

Senior HTF Member
Joined
Feb 24, 2002
Messages
2,588
Is there someone over at the HSU forum who might want to buy the latest generation VTF-3 after the shoot-out? No bottoming or audible distress will be allowed, and a strict 10% limit will be placed on THD, so the sub should be nicely broken in, but not abused, after the testing. I know it has been out of stock for a while, so there should be some takers?
You might want to ensure the Hsu sub is sold before you publish the results of your testing. :)
 

Robb Roy

Supporting Actor
Joined
Jul 15, 2002
Messages
711
Ed,

You mentioned posting results with pictures, etc. Let me know if you need any Web space for that, and I'll happily host that stuff at robbroy.net.

-Robb
 

Robb Roy

Supporting Actor
Joined
Jul 15, 2002
Messages
711
Oh, and if it gets too cold in NY, you're more than welcome to bring that unlimited beer to sunny AZ all winter long!

-Robb
 

Jack Gilvey

Senior HTF Member
Joined
Mar 13, 1999
Messages
4,948
As we discussed, a person can prefer the sound of a sub which actually measures inferior to a competitor. There is nothing wrong with that, but the choice to purchase should be made with that knowledge.

For example, some people actually prefer the sound of high THD at low frequencies. A 25 Hz tone with 50% THD will have a bunch of sound at 50 Hz and some at 75 Hz (and so on) and might sound "fuller" or "more complex" to some ears.
I remember reviews of the Sunfire "True Sub" that referred to the tremendous "bass presence". A boatload of harmonics along for the ride will tend to sound that way.



:emoji_thumbsup: :emoji_thumbsup: :emoji_thumbsup:
 

Edward J M

Senior HTF Member
Joined
Sep 22, 2002
Messages
2,031
I've got 5 meg of website space, so I'll probably be OK. I can remove some stuff if it gets crowded.

Oh, and if it gets too cold in NY, you're more than welcome to bring that unlimited beer to sunny AZ all winter long!
Tell me what you like. www.highfalls.com

Talk about a thread hi-jack. Color me guilty........:b phew!
 

Sasha_G

Agent
Joined
Mar 7, 2002
Messages
45
In terms of performance, I think a fairer competition would be HSU TN-1220 tube vs the SVS tube. Don't both cost around $849?

Or, how about the upcoming STF-3 box vs. the SVS box that costs $599? Our first generation STF-3 will be coming out at the end of the month.

Boxes vs. Boxes, Tubes vs. Tubes.

I'll try and get Dr. Hsu's permission for this. I like that Edward J M is looking at more than Max SPL. Almost nobody listens to constant 115 dB bass anyhow. There might be a split second peak, but that it.

Sasha
HSU Research
 

CurtisSC

Screenwriter
Joined
Jan 28, 2003
Messages
1,412
Thanks for chiming in Sasha!

OK....so if it can be worked out, TN1220HO with the Hsu 250watt plate amp($849 includes shipping) and the 20-39PC+($825+shipping) or 16-46PC+($875+shipping).

OR

The new STF-3($599 includes shipping) and the PB1-ISD($599+shipping).

I think that is what Sasha is proposing. Hope it can be worked out.

The nice thing is the I believe the TN1220 is in stock.
 

Rick Hilst

Grip
Joined
Oct 26, 2003
Messages
16
I have been at work and this has been my first chance to catch up on this thread.

I would like to propose that we do this using a "benchmark" approach. With a benchmark approach, the general procedure to follow would be:

o Define what the benchmark is to determine
o Define the criteria for the benchmark
o Determine who/what will be included in the benchmark
o Solicit input from the participants (i.e., vendors) in the benchmark as to their input on the benchmark criteria
o Adjust the benchmark criteria based on vendor input
o Get agreement from all the participants that the benchmark is a fair comparison. If a vendor chooses to drop out, then allow that vendor to explain why and include that explanation in the results
o Perform the benchmark. Give each vendor the opportunity to react to each result and offer suggestions on how to get "better" numbers. Be fair and do the best possible job of making each vendor's numbers look the absolute best.
o Analyze the results and publish the conclusions

I have other stuff I have to do now (I'm painting part of the house as part of the WAF for purchasing all this audio/video equipment). If I have time I'll post some ideas on the first two or three bullets later.
 

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