SVS PB2000 Subwoofer Upgrade
My current sub configuration is composed of two front SVS PB12-NSD’s and two rear SVS SB2000’s. So when I was given the opportunity to “upgrade” my front NSD’s to a pair of the newer PB2000’s subs I though that the new combination might give me a little extra something. So did it?
The PB2000’s are an upgrade from the NSD’s in that they have an improved driver and slightly higher power amplifier. The cabinet is the same as the NSD’s but the new driver and higher power amplifier are the same as those used in the SB2000. This results in improved bottom end response below 32Hz, providing a slightly higher SPL and being more extended.
Frequency Response Plots From The SVS Website.
For those that read my white paper on mixing and matching different types of subs you will have realized that such an upgrade it is not a straightforward process. So I was not particularly looking forward to going through what I went through originally. Although I had learn’t what to do to align the last four subs, this set of four unfortunately presented a quite different time, phase and EQ requirement. Read on.
I will spare you all the gory setup details, being similar, but much faster than the original EQ routine that I went through described in my white paper above. Fortunately after reversing my original phase inversion required for the previous subs, all four subs had positive impulse responses that were easily time aligned using my Rane ad22 dual channel delay, see graphs 2, 3 and 5. After setting each of the four subs to 75dB SPL and using REW to generate a 5Hz to 300Hz sweep, driving all 4 subs simultaneously, I ran the REW EQ routine to generate the frequencies, gains and Q’s that were entered into my SMS-1, an 8 band digital parametric equalizer. As always, the resulting measured rooms frequency, decay and impulse responses virtually matched those predicted by REW. Using the sub distance control in my Denon AVP A1 the equalized four subs step response was time aligned to that of the Audyssey XT32 equalized front Genelec 1038’s and the overall sub level was adjusted to match the 1038’s. Now basically all was done.
NOTE: I did not re-run Audyssey XT32 in my Denon AVP A1 as nothing had changed that affected the satellite speakers. I ran the REW sweep by including the Denon Audyssey XT32 sub EQ in the signal chain so it was taken into account during the measurements and REW EQ process. There was virtually no difference between the frequency, decay and impulse responses of the 4 subs either with or without the Audyssey EQ from the previous PB12NSD/SB2000 subs. I assume the reason being that the coefficients that were in the AVP Audyssey sub EQ were negligible, as it had been run over my previous very flat PB12NSD/SB2000 SMS-1 sub EQ (graph 4), that was very similar to the new PB2000/SB2000 response over the Audyssey EQ range.
So here is a quick overview of the subs various responses, nothing changed for the satellites:
Graph 1: Frequency Responses of PB2000 and PB12-NSD Pairs – No EQ
Note the lower bass output from the PB2000 between 5Hz and 20Hz. The PB2000 roll-off above 125Hz is due to the Audyssey sub settings in the Denon AVP.
The unequalized responses of the existing two SB2000’s is not shown as it did not significantly change. See the white paper pages 2, 7 & 8 for their responses.
Graph 2: Impulse Response of PB2000 Pair Only
Virtually identical and no timing Errors.
Graph 3: PB2000 & PB12-NSD Pairs Impulse Response Comparison -(Time Offset Removed)
Graph 4: SMS-1 Equalized Responses – PB2000/SB2000 Pairs (With AVP Audyssey XT32 sub EQ) & PB12-NSD/SB2000 Pair (Without AVP Audyssey XT32 sub EQ)
EQ at 13Hz or lower is not possible as the SMS-1 has no bands below 15Hz and the Denon Audyssey XT32 EQ assumes the dip is the systems natural bass roll-off point.
PB2000 roll-off above 125Hz is due to the Audyssey sub channel settings in my Denon AVP.
Graph 5: Impulse Responses For The PB2000/SB2000 and PB12-NSD/SB2000 Pairs After EQ – (Impulses time aligned for comparison)
Graph 6: Waterfalls For The PB2000/SB2000 and PB12-NSD/SB2000 Pairs
Graph 7: Group Delays For The PB2000/SB2000 and PB12-NSD/SB2000 Pairs
The PB2000/SB2000 group delay is far more uniform below 13Hz but higher.
Graph 8: Front Genelec 1038 Responses To 1KHz With The PB2000/SB2000 Sub Pairs Equalized And Time Aligned.
Sub crossover to all Genelec 1038’s is at 40Hz.
Result Comments
What was surprising was that the supposed improved bottom end response of the PB2000 shown above and in this earlier post did not manifest itself in my room as can be seen in graph 1. The PB2000’s frequency, phase and group delay responses did not integrate optimally when added to the SB2000’s and there was no way to improve it, resulting in an increased uneven response below 15Hz that could not be corrected and a room decay below 20Hz that was slightly inferior to my PB12-NSD’s, see graphs 6.
The good news was that the combined four subs provided a relatively flat frequency response down to 15Hz, see graph 4 and maintained a smooth crossover to all my satellites at 40Hz and 60Hz, see graph 8. Also the decay between 20Hz and 30Hz, see graphs 6, notably improved and is probably more audible than the small room decay increase below 20Hz (This increase is also a function of the increased levels).
So was it all worth it? To my surprise yes. I used my two reference vinyl test albums for a quick check; Mo-Fi – Dire Straits Brothers In Arms and Sheffield Lab 3 – The King James Version – Harry James and His Big Band.
The two most notable improvements were:
- Kick drums presented with a cleaner deep “punch” and “slam”.
- Acoustic double basses were cleaner, more “open” and had more “air” around them.
I have also watched several movies that have good bass and have noted an increase in bottom end “depth” and “punch”.
After extensive music and movie listening tests the PB2000/SB2000 decay increase below 20Hz was never audible, nor was the increased uneven frequency response below 15Hz an issue.
Only time will tell if I will return to my pair of PB12-NSD’s, but probably not!
Click on the following links for the SVS sub web pages:
Read my original post on aligning four subs here.
Here is my white paper on my original four sub alignment process SUB-SONICS.
