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SVS SB16-Ultra Sealed Subwoofer Measurements and Analysis

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The SVS SB16-Ultra was tested using ground plane measurements with microphone at a 2 meter distance in an open setting with well over 100 feet from the nearest large structure. The sub was tested with woofer facing the mic. The subwoofer’s gain was set to maximum, and the low pass filter was left off. Weather was recorded at 58°F and 27% humidity. 58°F is a bit lower temperature than what is dictated by the CEA-2010 protocol which specifies a range of 65°F to 80°F, but the difference that such a minor change would make would be minute.

SB16_Frequency_Response.jpg 

Frequency response of the SVS SB16-Ultra 

The SB16-Ultra’s frequency response is impressively flat. We measure a +/- 3 dB window of 18 Hz to 330 Hz. While that does not quite match SVS’s own spec of 16 Hz to 460 Hz, it is extraordinarily good nonetheless. The +/- 1 dB window is an astonishing 30 Hz to 200 Hz. This is a supremely linear sealed subwoofer. The low end seems to roll off at a slightly steeper rate than the expected 12 dB/octave slope typically found in sealed subs, and this suggests that a mild high-pass filter is implemented in the amplifier’s DSP. Some people might dismiss the usefulness of such an extended high-end response in a subwoofer as we see in the SB16-Ultra, but I do prefer having the freedom to run the speaker/subwoofer crossover higher than the standard 80 Hz without a gap in the bass response.                              

                      SVS SB16-Ultra CEA-2010 Maximum Clean Burst Output Measurements
                                             Referenced to 2 meters ground plane RMS

Test Frequency (Hz) Max Passing Measurement (dB) Total Harmonic Distortion (%) Harmonic Threshold Limiting
10 83.9 14.4 3rd Harmonic
12.5 88.8 15.6 3rd Harmonic
16 94.7 17.5 3rd Harmonic
20 100.1 17.6 3rd Harmonic
25 106.4 19.7 3rd Harmonic
31.5 113.1 13.5  
40 115.2 12.3  
50 116.2 7.4  
63 116.5 10.1  
80 116.0 8.2  
100 116.3 7.1  
125 116.8 9.7  

The above table shows the CEA-2010 measurements taken from the SB16-Ultra, which tests its burst output within certain distortion limits. They basically show how loud a subwoofer can be for a brief moment while staying somewhat clean. As always, our measurements have been referenced to 2 meter RMS, which is 9 dB down from the standard requirement for the measurements to be shown at 1 meter peak.

This is an excellent showing, particularly from 20 to 31.5 Hz. One feature that can be discerned right away is that the SB16-Ultra driver has more to give at 31.5 Hz and up, were the amplifier able to give more power. Above 31.5 Hz, this driver is taking all the juice that the 1,500 watt amp can give and is asking for more. Below 31.5 Hz, the driver can be pushed to its limits, but its performance ceiling in this respect is extremely good considering the driver diameter (SVS’s spec of a 16” is a bit generous; I measured 15.5” from frame’s edge). One interesting exercise we can do to get a sense of the differences between the overhung and underhung driver designs of the 16-Ultra driver is compare these measurements to those of the PB16-Ultra in sealed mode. We see that the sealed PB16-Ultra has more deep bass capability but the SB16-Ultra has more mid-bass capability.

Another interesting comparison we can do with the SB16-Ultra CEA-2010 measurements is put them up against SVS’s former flagship sealed subwoofer, the SB13-Ultra, reviewed by Audioholics. A couple of notable details emerge. First, we see that in the extreme deep bass frequencies of 10 Hz and 12.5 Hz, they are nearly on par, but the SB16 starts to pull ahead at 16 Hz and keeps its lead until 63 Hz. At 25 Hz and 31.5 Hz we see the SB16-Ultra has a very substantial 5 dB gain over the SB13-Ultra, nearly doubling its output. Above 63 Hz, the SB13 pulls ahead, perhaps due to a much lighter weight of its moving parts. 

CEA_10_12.jpg      CEA_16_20.jpg

CEA_25_31.jpg     CEA_40_50.jpg

CEA_63_80.jpg     CEA_100_125.jpg

Frequency Breakdown of CEA-2010 Burst Measurements for the SVS SB16-Ultra

The above graphs show the frequency spectrum of the increasing CEA-2010 bursts as reproduced by the SB16-Ultra. Essentially, it depicts the behavior of the subwoofer reproducing short burst tones at successively louder levels, with each test tone raised by boosting the input gain by 1 dB until no more output was to be had from the subwoofer. The frequency marked above the graphs note the fundamental tone being tested, and this can also usually (but not always) be discerned in the graphs by the horizontal axis frequency point of the “main ridge,” the highest levels on the vertical axis. The noise below the fundamental (that random spikiness to the left of the main ridge) should be ignored. What should be looked at are the smaller ridges to the right of the fundamental; these are the distortion products of the fundamental, and it is here where we see how cleanly the subwoofer handles a given output level. These are mostly harmonics: whole number multiples of the fundamental.

In these graphs, the SB16-Ultra shows itself to be an extremely low-distortion subwoofer. At low frequencies we can see that the third harmonic is always the dominant distortion product, which indicates a balanced design as far as excursion goes. The SB16-Ultra keeps things well-controlled in the deep frequencies until it is pushed to the edge of its performance envelope. This is ideal behavior, in that it gets the most out of the driver but does not let the driver fly too wildly past the point of linear excursion. In the upper frequencies, the second harmonic becomes the predominant distortion product, but it only appears in vanishingly small quantities, and certainly nothing that is audible. It is likely the result of induction, and the SB16-Ultra remains extremely clean at these frequencies even when pushed as hard as possible. This is evidenced in the CEA-2010 measurements where distortion, at its worst, was still only measured in single digit percentages for many of these frequencies. To sum up the behavior here, the SB16-Ultra has relatively clean output in deep bass for a sealed subwoofer, and no significant distortion to speak of at 50 Hz or above. Exceedingly linear performance is on display here.

SB16_long_term_compression.jpg  

Long-term Output Sweep Measurements for the SVS SB16-Ultra 

SB16-Ultra shows itself to be an extremely low-distortion subwoofer.

Testing for long-term output compression was done by first conducting a sweep tone where 50 Hz hit 90 dB with the subwoofer 2 m from the microphone. We then conduct further 20 second sweeps by raising the gain by 5 dB until no more output could be rung out of the subwoofer. In these tests we can see that the SB16-Ultra does not start to lose its shape until the 105 dB sweep, although not by much at that point. At the 110 dB sweep, the low-end rolloff rises to the mid 30 Hz range, and the response knee becomes sharper at the highest output sweep, after which the SB16-Ultra was not able to produce any more output. This compression behavior is overall pretty good. The ideal is for the frequency response to maintain its same exact shape from low output levels to the highest output level, but, of course, that will never occur in practice. In practice, however, the response of the SB16-Ultra does not change dramatically. The rolloff does hike up to about 35 Hz where some response from the upper teens to 35 Hz is lost, and that is the driver losing its EQ’d shade by running out of displacement ability.

There is a lot of output to be had here. From 40 Hz to nearly 200 Hz, the SB16-Ultra is running right along 114 dB at its highest sweep level. SPLs below that level are good as well. Using the SB13-Ultra as a point of comparison, at 60 Hz and above they have about the same output, but below that point the SB16-Ultra’s displacement advantage gives it a clear lead. From 20 Hz to 40 Hz, the SB16-Ultra holds about a 4 dB advantage, which is about a 60% increase in performance.

SB16_THD.jpg 

SVS SB16-Ultra Total Harmonic Distortion per Long-Term Output Sweeps 

The above graphs show total harmonic distortion for the sweeps done on the ‘Long Term Output Compression’ tests, and they essentially depict at what drive level and frequency the subwoofer loses linear playback. The performance shown here by the SB16-Ultra is very good for a sealed subwoofer of its size. As seen in the CEA-2010 testing, this is an extremely low distortion subwoofer above 30 Hz. At nominal levels of 90 and 95 dB, the SB16 hovers around 1% THD above 50 Hz, which is about as low as most popular music digs. Even when pushed to the very edge in this frequency range, it doesn’t surpass 5% THD, and this makes the SB16-Ultra a superb choice for typical music recordings. In deep bass, distortion does not go over 20% THD for 90 and 95 dB at any frequency. Once pushed to the 100 dB sweep level, it does surpass 20% THD, but is still mostly in control of itself. Below 20 Hz and above 105 dB, it does start to lose control, but few sealed subwoofers can hold it together in this performance region. There is a lot to admire here, both for mid-bass performance and deep bass performance.

SB16_Harmonic_2nd_3rd.jpg     SB16_Harmonic_4rth_5th.jpg

SB16_Harmonic_6th_7th.jpg     SB16_Harmonic_8th_9th.jpg

Component harmonics of the SVS SB16-Ultra 

The above graphs depict measurements of the constituent harmonics from the long-term output sweeps. These are the individual harmonics that compose the total harmonic distortion graph above them. As with the burst testing, we see that the third harmonic is the chief offender here, and it mostly rears its head below 25 Hz. This is where the driver is running out of excursion, and we can see that since the third harmonic is what is cropping up above all else, that both sides of the cone’s travel are being inhibited, by either the suspension or the voice coil leaving the ‘gap’, or the region of magnetic flux that it reacts against. This distortion profile indicates a high level of optimization for the driver. The more audible higher-order harmonics are insignificantly low until the SB16-Ultra reaches the bleeding edge of its performance envelope. The overall picture here is that the SB16-Ultra will not produce audible distortion until driven to its limits, and even then it would only occur at deep frequencies. 

 SB16-Ultra Group Delay v2

Group Delay of the SVS SB16-Ultra 

Group delay is the measurement of how much time it takes for individual frequency bands of an input signal to be produced by the speaker. It can indicate that some frequency components are developing slower than others or are taking longer to decay. It is generally thought that 1.5 sound cycles are needed for group delay to be audible at bass frequencies, although there is an argument that group delay should remain under 20 ms to be completely unnoticeable, but that is likely meant for mid and upper bass frequencies. The SB16-Ultra puts on a very good showing here. Group delay doesn’t surpass one cycle until just above 30 Hz, at which point it is far too deep in frequency to approach audible, which is still the case even as delay surpasses 1.5 cycles at just above 20 Hz. In the region where group delay would be a concern, the SB16-Ultra keeps everything below a single cycle. The SB16-Ultra sounded tight and didn’t exhibit any overhang in my listening sessions with it, and this graph explains why. This sub is as sharp as a tack.

 SB16_Low_Pass_Frequency_Effects.jpg     SB16_Low_Pass_slopes.jpg

Low-Pass Filter Effects of the SVS SB16-Ultra 

The above graphs simply show the effects of some of the low-pass filter settings, with the left graph showing the range of frequencies that can be filtered and the right graph showing the effects of the different slopes. The SB16-Ultra has a low-pass frequency range of 30 Hz to 200 Hz using slopes of 6, 12, 18, and 24 dB per octave rolloffs. For those not using external bass management, the SB16-Ultra should be able to find a frequency and slope that will help it blend in with the main speakers seamlessly due to the very fine adjustments that can be made with its low-pass filter.

 

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Recent Forum Posts:

RXP posts on March 04, 2019 03:54
shadyJ, post: 1216024, member: 20472
It does very good in deep bass for a since sealed subwoofer of its size. If you can accommodate a ported sub, like a PB13-Ultra, you can get a lot more deep bass output for the same price. The extension rating in this case ignores the distinction between ported and sealed subs, because the truth is a lot of people do not understand the difference between ported and sealed subs. Those who are after deep bass around the same price point can do better if they can handle larger enclosures.

I based my purchasing decision on this logic when I went for an SVS PB13 in my main theatre. Then I wanted a sub for my office I was shocked at the performance of the SB2000 I ordered for a smaller room (4mx2.5mx2.6m )

In the US the rooms tend to be bigger, but in the UK they're smaller. I made a PVG calculator that's available here. Just input the yellow cell. Any errors you notice let me know. The slower roll off of a sealed sub works really well in smaller rooms. Of course, the rigidity of walls and the materials of your house mean you may get significantly less.

Knowing now what I know - I'd have preferred to get a couple of sealed PB13's. I'd get deeper extension in my room at reference levels and save some space. They're also much easier to move around and ship if you decide to sell. Of course if I had a much larger room, ported is the way to go. Hopefully the Pressure Vessel Calc makes that clear to potential purchasers
shadyJ posts on October 18, 2017 12:18
It is generally not a good idea to mix ported and sealed subs, if all those subs are in one system.
Rolljdc posts on October 18, 2017 10:32
I know the difference in ported and sealed box subwoofers as I have a combination of both (Rythmik D15SE, Rythmik LVR12, 2 Golden Ear Forcefield 4's, and the aforementioned SVS SB16 Ultra. I know that ported or one with passive radiators extends deeper and has more output than sealed, and sealed is a thighter and speedier but less output and less deeper extension. As you can see, I have a combination of strengths and weaknesses in my system. The question is since the SB16 have substantial output in the 16-30hz, why would you rate it 4 star? Also the sound is probably the best I have heard in my past ownership of subs, and it ranks below the PB16? Just sayin (my opinion)…..
shadyJ posts on October 16, 2017 19:34
Rolljdc, post: 1216006, member: 83881
“The SB16 isn't just about performance. Yes, if you want raw SPL, there are other subs that can get louder. The SB16 has good performance, extensive features, great looks, and all the customer service amenities that come with SVS. Regarding performance, the SB16's wheelhouse is the range of 16 Hz and 30 Hz. No other 15” is going to touch it there."
I just got done setting up and listening with my SB16 Ultra. What the review said about the deep bass performance and extension, well should'nt that warrant a 5 star rating for the extension? Just scratching my head about that.
It does very good in deep bass for a since sealed subwoofer of its size. If you can accommodate a ported sub, like a PB13-Ultra, you can get a lot more deep bass output for the same price. The extension rating in this case ignores the distinction between ported and sealed subs, because the truth is a lot of people do not understand the difference between ported and sealed subs. Those who are after deep bass around the same price point can do better if they can handle larger enclosures.
Rolljdc posts on October 16, 2017 16:43
“The SB16 isn't just about performance. Yes, if you want raw SPL, there are other subs that can get louder. The SB16 has good performance, extensive features, great looks, and all the customer service amenities that come with SVS. Regarding performance, the SB16's wheelhouse is the range of 16 Hz and 30 Hz. No other 15” is going to touch it there."
I just got done setting up and listening with my SB16 Ultra. What the review said about the deep bass performance and extension, well should'nt that warrant a 5 star rating for the extension? Just scratching my head about that.
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