$600 Subwoofer Shoot-Out: SVS PB1-ISD vs. Hsu STF-3 – Test & Review (1 Viewer)

[terence]

The disc has had that effect on me.

 

[Edward J M]

Hi Dave:

If you reference the Tech Section at the end of the report, you will see I had both the mic and the phantom power source professionally calibrated as one unit. I have over 250 correction factors that Kim Girardin provided to me, that were imported into the software.

Kim also gave me five FR curves for five other (different) ECM8000's he has tested in the past. They all have a somewhat different response curve, with most of the differences being in the 30Hz, and both subs certainly meet that criterion. If 114 dB at 30 Hz isn't enough for you, I don't know what is!

The output capability in the 20-30 Hz region is what separates good subs from great subs; that's why we call them "sub"-woofers. And that's why Hsu offers the variable tune VTF-3 and SVS offers the variable tune PB1+ and the PC+. And along the same vein, that's why the TN1220 and the 16-46 enclosures exist - some people want/need/crave high output at the lowest octaves.

But for a fixed tune box sub like the STF-3 and the PB1-ISD, the designer has the tough job of striking the best balance between sheer output capability, extension, and clean output at the lowest usable frequencies. With the advent of DVDs that contain loads of signal content in the 20-25 Hz region, usable extension and output in this frequency range takes on more importance - the customer expects the fixed tune sub to do justice to nearly all HT DVDs and music too. That's a tough order to fill!

Ed

 

[Rudi B]

That is not true. MP3 compression doesn't affect the infrasonics (and most parts of the audio spectrum) in any measurable or audible way. It will only cut the higher frequencies, 10Khz and up. Depends on the bitrate.

These two CDs aren't distributed via Internet because such was the deal with the organist that played on the recordings.

 

[David_Rivshin]

I'm assuming these include measurements up to 20KHz or higher? If so could I bother you for those? I use my ECM8000 for equalizing my mains and surrounds as well (Sony DA5ES with built in 3-band parametric EQ), and I believe I've seen FR numbers which indicated the ECM8000 was not flat near the extreme high end.
I'm not lucky enough to have access to equipment to measure the response of my mic, but an average of a small sample should be enough to get me into the ballpark.


Guess that also means that the RS SPL correction numbers are way off (at least for my meter) below 20Hz. *goes and looks at those values* Something doesn't make sense. In order for my ECM8000 and UB802 to be flat to 15Hz, the RS meter would need to actually become more efficient below 20Hz, and 15Hz would be the same sensitivity as 25Hz.
Perhaps the mic input on the UB802 has high pass on it at 20Hz? I think I measured the 1/4" input jack on the same circuit to be flat, but maybe I should do that measurement again. *checks specs* says bandwidth of 5Hz-100kHz, which doesn't exactly match with the theory of down 8dB at 15Hz.
*scratches head* something strange is going on here...

-- Dave

 

[Zack_R]

Awesome review Ed! Simply incredible what your enthusiasm and dedication to the hobby has afforded us!

I really like the objectiveness of the report. A lot of pro reviewers should be taking notes!

It's also interesting that the blind listening preference test pretty much confirms the THD / SPL / freq. response measurements. Both subs seem to be great performance values for the price and both companies should be proud of their achievements.



Yes, definitely. I can't think of too many people buying a sub for non-action type movies. It's often reported how few movies have bass content below 30 hz and even fewer movies with bass below 25 hz, seemingly to justify a particular subs weak

 

[Edward J M]

Dave,

Here are the correction factors for my particular ECM8000 and the UB1002 combined. As you know, they are specific to my test rig and cannot be applied to yours. As you can see, the rig was really pretty darn flat to begin with.

If you want to use them to "get into the ballpark", that's OK with me, but I wouldn't rely on them to stand up to third party scrutiny in a formal review. Enjoy!

It wasn't too expensive to get the rig professionally calibrated. Kim was very nice to deal with and I recommend him:

Kim Girardin
Wadenhome Sound
1400 Homer Rd. Suite 2
Winona, MN, 55987, USA

Phone: 507-454-8844

E-mail: [email protected]

Regards,

Ed


Edit: Numbers pulled to save screen space. I assume you have them by now, Dave.

 

[Edward J M]

Dave:

The PQ isn't the best, but here is the 5 mic overlay for the ECM8000. As you can see, most of the variation lies in the

 

[Edward J M]

Thanks for the kind words, Zack. Yes, it was pretty cool to see a trained set of ears (guitar and drum are his speciality) independently confirm what I had already measured.

Of course, he also heard the PB2-Ultra afterward, and that really impressed him too.

I agree - and I said as much in the review - these are both fine subs. Coming from a 20-39PC+, a PB2+, and now a PB2-Ultra, I'm pretty picky.

Another explanatory note: My relative scores are for the $600 price class. They cannot possibly be applied on a absolute basis, as there is simply too much variability in the world of subwoofers for that to be a valid approach.

If you buy a DD-18 for around $4,000, you can expect things like a remote control, GUI, 8 band auto calibrating PEQ, and all the rest of the goodies.

In comparison, for $600 I expect all the standard features on the sub amp. If it has the standard stuff and it seems to be well built with quality switch gear, then it gets like a good rating (say 80%). If it has additional features not commonly found in this price class (like a CV phase control, or variable tuning switches, or a single band PEQ, then it would rate higher (say 9-10).

Ed

 

[ScottCHI]

omg!

very impressive review.

somehow i missed it initially.

 

[Shane Martin]

Yeah I saw that too. Apparantly marko thinks that Ed is biased. Reading this review I would have thought that not to be the case.

 

[Richard_M]

Ed...

Thanks for posting the details for the Microphone, just have a couple of questions.

1. How does the temp/humidity affect the mics performance?

2. How long does the mic need to be powered on for it to stabilise?

Just trying to find out how much either of these things affects the mics performance.

Thanks

Richard

 

[Edward J M]

Hi Richard:

The UB1002 needs one minute to stabilize the phantom power source circuitry.

Well constructed condenser mics are apparently relatively immune to moderate changes in temperature, humidity, and barometric pressure. While I have no empirical data on the EM8000, B&K has some for their mics; I have provided a link for you to research.

The temp/humidity in the test household are typical and stable. Any change in mic performance (however small) would equally affect the results for both products, and as such a non-variable.

http://www.bk.dk/pdf/Bp0459.pdf

Regards,

Ed

 

[Richard_M]

Thanks for the info & link Ed...

I have always been curious that was all, but thanks I now know.


Richard

 

[Sebastian]

Ed,

That is one awesome review! I appreciate your time that you spent on it.
Thanks for posting it and sharing it with everyone!:star:

 

[Edward J M]

Thank you Sebastian.

To all readers:

I have been asked by several people to run THD-limited output in the >30-60 Hz region, just to provide a more complete picture of the relative clean output capabilities of both subs over a wider frequency bandwidth.

Any suggestions on the frequencies? I was thinking 35, 40, 50, and 60 Hz. What are your thoughts?

I was also asked to post the 18 Hz THD data, since the PB1 was noted in the report as having a significant extension advantage in the 18-20 Hz region. The people who made this request basically felt if I was going to note an extension advantage for the PB1, that I should also post the clean output capabilities of each sub at that frequency to provide a more complete picture. I really couldn't argue with the logic. What are your thoughts?

Regards,

Ed

 

[Robb Roy]

Ed,

I can't argue with the logic of the 18 Hz THD test, either, and can't wait to see it.

For the above 30 Hz tests, I'm not sure it tells much of interest to those who aren't masochistic -- both subs will be ridiculously loud. Then again, my own morbid interest would have me reading that material in no time flat.

-Robb

 

[Edward J M]

I know.....my thoughts exactly. Like I said in an earlier post, the data below 30 Hz is always the most important about how the sub will perform. Most subs really do tend to stablize in the 30-60 Hz region in terms of clean output, and Craig's data on the subs he is testing certainly corroborates this.

 

[Zack_R]

I'd actually like to see the testing below 30Hz to be in smaller increments for future reviews.

Something like 20, 23, 25, 28, 31.5. If the sub can go below 20 hz then I'd like to see a 16 hz and an 18 hz test.

Above 30 hz I agree with your suggestion.

The reason for the small increments below 30 is to understand the implications port plugging has on a given sub with that feature. The 5 hz increments will tend to leap frog over the additional demand placed on the speaker (potentially more THD) when tuning a sub down.

 

[Edward J M]

Definitely, Zack. That's why I did 20, 22, 25, 30. In addition to your excellent comments on the porting, it's important not to use too large of a jump, since a few Herz in the 20-30 Hz bandwidth represents a pretty large percentage of an octave. For example, dropping from 25 Hz to 20 Hz is about 1/3 of an octave.

 

[Edward J M]

Update:

I re-did the entire FR and THD data set for these two subwoofers, primarily for the following four reasons:

1) I installed a new audiophile grade sound card with a powerful DSP, 24 bit DACs, and a 108 dB S/N ratio. It has a lower noise floor, a much higher dynamic range, and better response characteristics to a digitally generated sweep.

2) In order to be completely consistent with Nousaine's methodology, I revised the method of calculating THD. The total SPL being seen by the mic is now being used to calculate THD.

3) I tracked down and isolated (this took nearly 50 hours) a code interaction problem between two TrueRTA program files which was causing a slight disparity between the total SPL being seen by the mic and the aggregate sum of the 1/24 octave FFT bins. The issue has been corrected, and the SPL calculator now correlates exactly with summation of the FFT bins.

4) The THD test frequencies were expanded and now include 18, 20, 22, 25, 30, 35, 40, 50, and 60 Hz. "Average SPL" results have also been calculated over three separate bandwidths for each subwoofer, using two methods - the mathematically correct method, and the more commonly accepted method used by Nousaine (which is a simple averaging of the dB values).

For the upcoming PB2-Ultra review, I will probably use a 5% THD limit (at least at the higher frequencies), since 10% THD from that monster in the 30-60 Hz bandwidth would probably get into the 135 dB range at one meter!

Finally, a better explanation of the rating/scoring system, and a more complete description of the amplifier feature set has also been included in the revision.

The Hsu STF-3 gained some ground in a few test areas, and the individual ratings and overall score naturally reflects that. The PB1 still scored higher overall with better deep extension and a higher overall THD limited output, but it was a close contest.

These method updates and revisions will naturally be included in all future product reviews, so it really became extremely important to generate a new data set from these two subs before they get sent to their new homes.

I hope readers and prospective buyers find the revised report useful in making an informed purchase decision.

Over the next few months, look for a few other sub reviews (besides the SVS PB2-Ultra) from different manufacturers.

That's about it!

Regards,

Ed