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

[ScottCHI]

what color carpet?

 

[Lew Crippen]

I suppose that outdoor testing would call for green or perhaps brown.

 

[Poh Ser]

Not being able to measure outdoors due to weather is the reason I moved from Boston to Sunny So. Cal! I can do a lot more testing outdoors throughout the whole year.

My remark about even reviewers can make mistakes was in response to your comment about how we 'suddenly invalidated all the indoor THD data that Hsu Research has quoted for years that was generated by icons like Tom Nousaine, Floyd Toole, Howard Ferstler, Don Keele, and John Johnson'. It was not aimed directly at you. As I pointed out, Don Keele does his distortion measurements outdoors. Unless you can prove otherwise, I think my observation about how room acoustics can potentially bias the test results is a valid point.

Clearly I do not expect our test results to match. Besides test equipment differences, how the test equipment is used, background noise levels, unit to unit variations in the subwoofer and test equipment will make the results differ.

Looking at your harmonic distortion results, it showed 10 dB difference in max output at 10% harmonic distortion between 40 Hz and 60 Hz for the SVS. My guess is its due to room effects. My measurements of the SVS outdoors showed less than one dB difference between 40 and 63 Hz (I use 1/3 octave data points like all the other reviewers do). I would suggest that you take your SVS outdoors and see if you still get the 10 dB difference in output between 40 and 60 Hz with the 10% harmonic distortion criteria.

Also, looking at your spectra for the 20 Hz distortion test for the SVS, you may not have used a large enough sample for your analysis. The spectra around the fundamental should fall off more quickly. My best guess (I don't have TrueRTA, so if there are experts on TrueRTA out there, please correct me if I am wrong)is that your sample size is too small for the program to apply a very steep filter to give accurate results. Certainly you should NOT be adding the spurious sidebands around 20 Hz to get a 'total' output. It is simply there because the filter is not steep enough. The 20 Hz signal is being picked up by the 19 Hz band. When you feed a subwoofer 20 Hz, it does NOT generate 17, 18, 19, 21 or 22 Hz. Also, how accurate is the signal you are feeding the subwoofer? I see the peak in the spectra is one band below 20 Hz.

Regarding your comment about my not having sent you the STF-2, I need to point out that I never received a reply from you. I do not have your address or your agreement for me to send you a STF-2 for measurements. Not surprisingly, I have not sent you the subwoofer if I did not get your address or your agreement to do a retest.

Lt us start out with the STF-2. PM me your address and phone numbers.

 

[Edward J M]

How unfortunate. I replied immediately to your PM last week. I will resend my reply to you at once. You will note my original reply was probably within 30 minutes of receipt. Sounds like HTF was responsible for that glitch. Please check your PM mailbox.

Finally, I have a question regarding your testing of the PB1-ISD (and I mentioned this in my PM reply to you also). When you removed the baseplate, did you reinsert the screws into the enclosure to seal the holes? If not, the PB1 enclosure will leak air from the screw receptacle holes, and the performance will be significantly compromised. Please retest the PB1 if this was the case.

Regards,

Ed

 

[Poh Ser]

Of course we did screw back the screws after taking off the base plate. The same applies to testing our subs - even though the subs are laid on their sides, we have the feet screwed in. You don't seriously expect us to forget to do something that elementary...

 

[Edward J M]

Never hurts to double check, no offense intended. I trust you received my PM? If so, I look forward to receiving your STF-2 and I will share all test data with you, and I hope you do the same so we can compare FR and THD notes under identical test conditions. I will test the STF-2 in exactly the same manner you do.

 

[Poh Ser]

Yes, I did. Thank you. I sent a reply to your email address rather than the PM. I don't check my PM much, so I prefer for you to email directly at [email protected]. I will send out the sub next week sometime. Have a good long weekend.

 

[Matt_Smi]

This should be interesting, as an STF-2 owner, I look forward to your test results of it Ed

 

[frank manrique]

quote:

"Not being able to measure outdoors due to weather is the reason I moved from Boston to Sunny So. Cal! I can do a lot more testing outdoors throughout the whole year."

Oh, yeah? Where in So. Cal...Orange County? LA County? San Diego? Or Riverside County?
Man, So. Cal is soooo damned overcrowded (and am being generous!) and rife with noise pollution at any given time in daylight hours that I it find hard to believe that any outdoor measurements can be taken without tainting or skewing the results somewhat...

-THTS

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

 

[Craig Chase]

Frank - I just tested my B4+ outside, and there was a concrete truck pouring a foundation for a new house, traffic noise... generally 60 dB of background noise on average.

I don't think it hurt the results. By the way, it did hit 118 dB outside at 20 Hz... with below 10 % distortion, at 119 dB, distortion jumped to 13 %... so I stopped there

I think Poh Ser Hsu is likely able to test outdoors. I also think Ed is quite capable, too.

I am looking forward to the results here...

 

[Edward J M]

Outdoor measurements are best, certainly. I try to test outdoors when I can, but in upstate NY, that's about 5 months of decent weather. The next comparo or shoot-out - if it occurs within the next few months - will have outdoor measurements included.

Maybe I'll build a little testing platform outside with some heat tracer.....yeah, that's it.....

 

[Craig Chase]

Ed - Yes, it was tuned at 20 Hz... And it is a scary thing to do with a $2500 passive subwoofer.

The K2 is a monster, also... The clip lights did not come back on...

OH... and the cement truck is safe... PHEW !

 

[CurtisSC]

There are very quiet areas...mine is great.

I would think you could take measurements of the ambient noise as well...and then calculate them out.

 

[Craig Chase]

Curtis, you are right, there are quiet places anywhere. Besides, even 60 dB of background loise is neglible.

For example, against a 120 dB peak subwoofer output, the 60 dB background noise we had here would represent 0.1 % THD... neglible in this type of testing.

And I am sure Dr. Hsu will not have a cement truck one block away...

 

[Edward J M]

Not even.

120 dB + 60 dB = 120.00000434 dB. No, I'm not kidding.

 

[Cam McFarland]

Can't let it rest.....you guys probably point & laugh at
the mentally challenged, too...........

 

[Craig Chase]

Cam - I Totally agree... especially when Poh Ser Hsu has taken the time to work with Ed and HTF on continuing the test process....

I love good banter as much as anyone (I know, a shock...

But... This went over the top...Gents... please, no more smarta** comments, ok?

 

[frank manrique]

quote:

"Ed - Yes, it was tuned at 20 Hz..."

You mean 20 Hz with one vent plugged?

"The K2 is a monster, also... The clip lights did not come back on..."

What does this mean? Please enlighten me as I'll eventually go the Crown amp route too!...

-THTS

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

 

[frank manrique]

quote:

"There are very quiet areas...mine is great."

Yeah, well...I wish you would have seen Redlands back in late '69 (and even through the late 80s for that matter) when I first moved in with my newly acquired bride (a native Californian born in Whittier but raised in this University town since she was two years old--do the math!)--it would have re-defined the phrase "great quiet areas" for damned sure... :rolleyes

-THTS

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

 

[Lee-c]

Well, with the PB1-ISDv coming out soon for only $100 more, there will be no contest in this
price category for box subwoofers. This supercharged version of the PB1-ISD is going to
be even more incredible.

I wonder how much boost in SPL at 18, 20 and 25Hz we will see with the v version. Any guesses, Ed?