SVS PB16-Ultra Ported Subwoofer Review

[Auditor55]

I enjoyed the review. It was very thorough and seemed quite objective. I am a little confused about one aspect of the measurements, though. Is your testing methodology the same as Josh Ricci's? I remember that he is also testing at 2 meters ground plane, but are there other differences?

The reason I ask is because I have both the PB13 and the PB16, and the 16 seems to have audibly deeper extension than the 13. That is consistent with SVS's claimed performance for the sub, which indicates a one port tune of 13Hz (not 17Hz) +/- 3db. It is confusing to me that the 16 would have 4db more output at 16Hz (comparing Data-Bass numbers for the PB13 in one-port mode) but have almost identical performance at 12.5Hz.

I know that, in addition to claiming more low-end extension on the SVS website, and in thread posts, that was a specific design goal for the new PB16. The disparity in your tested performance and theirs at 280Hz seems essentially irrelevant to me, as you suggested. But, the disparity in performance below 16Hz is far more significant in my view, and more difficult to understand, given the larger cabinet, driver, excursion, port tune, etc. compared to the PB13. It also seems inconsistent with the observed performance that PB16 owners, including myself, are reporting.

Is this an issue that you were aware of and can comment on? Again, I am extremely surprised that you measured the PB16 (with a reported 13Hz port tune) at only 89.1db at 12.5Hz, when the PB13 (with a 15Hz port tune) measured 89.3db. Is this a difference in testing methodology between you and Data-Bass, and/or SVS?

Thanks for any clarification on this issue. I have three of the new PB16's (that I upgraded from 13's) in a large room, along with a nearfield PB13, that I kept. Even nearfield for increased tactile response, and level matched with the 16's, my 13 does not go quite as deep as the 16's, so this is something I would like to understand better.

Regards,
Mike

How large is your room?

 

[Auditor55]

Hello David,

It would be great to review the SB16, but for myself, I will not be able to review subwoofers until the spring, sadly, so if that does happen, it won't be for awhile.

As for the group delay, I am guessing that the higher levels of delay in the PB16 are probably mostly due to the subsonic filters used to protect the driver. The nonstandard driver designs and somewhat larger enclosure might also be contributors. But, like is stated in the article, this delay should not concern you, it is far too low in frequency to be offensive or even audible.

I really would like to get a review of the SB16.

 

[Auditor55]

Still no update on SB16 review?

 

[shadyJ]

It looks like a SB16-Ultra review will be happening but not until the spring, perhaps an April/May time frame. Sorry for the delay, but groundplane measurements are not possible in this neck of the woods until then.

 

[Andron]

I'd like to propose my answer for the phenomenon, James Larson noticed in the review, saying:

One slight oddity is that the second harmonic actually decreases as a percentage at the highest sweeps, and I don’t know why that would be, except if maybe the limiter became more active above a certain output level.

I think it's because of the 'natural limiter' of the reflex alignment = port compression.
I read, the port produces 2nd order distortion.
When the port compresses, the Subwoofer becomes yet a bit more like a closed box around the tuning frequency.
Cone excursion increases which leads to increased 3rd order distortion BUT the air in this, now semi-closed box, actually decreases harmonic distortion relative to the cone excursion due to linearization of Kms(X) of the driver's suspension, due to the now more prominent air spring coming into play again.
So, while the fundamental output decreases compared to the driver's excursion, it's more than compensated by the reduced, port generted harmonic with further reduction of the said 2nd harmonic by the now prevalent air spring. I can be wrong. Just a curious thing.

 

[shadyJ]

Interesting idea that port compression will make the driver behave as though it were in a sealed enclosure. It makes some sense though. Also an interesting idea that port compression will reduce port distortion relative to cone excursion at high output levels. A good way to investigate that would be to take a variable tuned sub out for a day and do much finer sweeps that what is in those charts, and then compare the 2nd HD vs 3rd HD for various port settings. I probably won't have time to do that myself, but maybe on a slow day during testing its worth a look.