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Starke Sound SW15 and SW12 Subwoofer Measurements & Conclusion

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 SW12 outdoor testing.jpg

Testing on the SW12 and SW15 was conducted with the microphone facing the woofer at a 1-meter distance and then scaled back to 2-meters in our graphs by subtracting 6dB in output. The temperature was recorded at 65F degrees with 80% humidity. The subwoofers’ gain was set to maximum, phase was set to 0, and the low pass filters were left off.

SW12 SW15 freq responses.jpg 

The above graphs show the measured frequency responses for the SW12 and SW15 subwoofers. Both subs exhibit a fairly neutral response, although the +/-3dB windows of the manufacturer’s specifications do seem somewhat optimistic. These subs hold a flatter response down to deep frequencies than what would be expected of a sealed subwoofer, and that is due to DSP shaping of the response. The SW12 has a bit more energy in the response in mid-bass frequencies, and I would guess that is due to the lighter moving mass of the smaller cone. For the same input level, the SW12 might sound a tad punchier, at least until it reaches its limits. Both subs do have usable output above 80Hz although it is a bit down in level compared to the rest of the frequency range. Nonetheless, they should be able to accommodate higher crossover frequencies should the user wish for that.

SW12 CEA2010 measurements.jpgSW15 CEA2010 measurements.jpg

Bassaholic LargeThe above CEA-2010 measurements are short-term bursts that show the subwoofer’s clean peak SPL before heavy distortion sets in. Our measurements have been referenced to 2-meter RMS, which is 9dB down from the standard requirement for the measurements to be shown at 1-meter peak. However most publicly available CEA-2010 measurements are shown at 2-meter RMS, so we followed that convention. Both the SW12 and SW15 put up a good showing here with unexpectedly strong measurements in deep bass output at 31Hz and below. I would guess that was a range that Starke Sound wanted to engineer the drivers to have particularly good performance in seeing as how they were not going to have the benefit of ports or passive radiators. These measurements leave no doubt that these drivers have a serious amount of displacement for their size. The SW12 earns a Bassaholic “Medium” room rating, and the SW15 earns a “Large” room rating. (read more about Audioholic’s Bassaholic room rating system). The SW15 roughly averages around 3dB more headroom than the SW12, and that is about what one would expect given the design differences. In my listening experience, I would have sworn it had more headroom than just that, but that could have been also partly due to the fact that the SW12 hit its head on the ceiling much more audibly when pushed to the limits. The SW15 seems to have a more pronounced level of output at 50Hz to 63Hz that we will get a closer look at below in our long-term compression testing. 

SW15 compression sweeps.jpg 

Testing for long-term output compression was done by first conducting a 20-second sweep tone where 50Hz hit 90 dB with the subwoofer 2 meters from the microphone. We then conduct further 20-second sweeps by raising the gain by 5dB until no more output could be wrung out of the subwoofer. These tests show us the long-term continuous headroom that the subwoofer is capable of. I was not able to fully test the SW12 using this method since it shut down output at high levels in deep frequencies, so only the results for the SW15 will be shown. The SW15 retains its response shape up to 95dB before compression starts to squeeze low frequencies. At higher drive levels, it ends up with a peak centered between 50 to 60Hz which I would guess is the result of induction. A shorting ring or two might have flattened the response out more at the higher drive levels, but it would also have incurred more cost for manufacturing the driver. 

SW15 THD.jpg 

The above graphs show the corresponding total harmonic distortion to the long-term output graphs. Essentially, they depict how linear the subwoofer remains for the corresponding drive level seen in the long-term sweeps. The quantity being measured is how much of the subwoofer’s output is distortion and is shown here as a percentage. The distortion performance shown here by the SW15 is fairly good. At nominal drive levels, distortion is extremely low, hovering around 1% in mid-bass at the 95dB test sweep and not even breaking 10% until near 10Hz. Even at the maximum drive level, distortion is not bad in mid-bass and can barely break 10% which is very unlikely to be audible in real-world content. As with all sealed subwoofers, distortion skyrockets in deep bass as the driver reaches the end of its linear throw. Distortion doesn’t really blow up in deep bass until the 105dB sweep, and we have to keep in mind that this sub rolls off its response rapidly below 20Hz, so its output, distorted or otherwise, is significantly lower than output above 20Hz.   

SW15 2nd harmonic.jpg   SW15 3rd harmonic.jpg

The above graphs depict measurements of the constituent harmonics from the long-term output sweeps and are what the total harmonic distortion measurements are composed of for the 2nd and 3rd harmonics. These individual harmonics can give us a clue as to what might be the cause of some quirk or non-linearity. We are only showing the 2nd and 3rd here because they more or less reflect the higher even-order and odd-order behaviors, although higher-order harmonics tend to be much further down as a percentage of distortion compared to the second and third. Much of the mid-bass distortion of the SW15 looks to be a consequence of induction. We can see this since most of the distortion in that range is even-order, and there is a notch coincident with the peak of the response. If the even-order distortion were the result of some asymmetry of the motor force or the suspension, it would likely be more even across the entire bandwidth rather than leaving a notch at 50Hz. Its correspondence with output level also looks to be more steady rather than a sudden jump; a sudden jump in distortion would indicate the driver has hit some kind of travel limit, but induction-based distortion rises at a more even pace. Again, the use of shorting rings would have significantly reduced distortion above 50Hz, although what distortion there is not a whole lot.

SW12 SW15 group delay.jpg 

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 20ms to be completely unnoticeable, but that is likely meant for mid and upper bass frequencies.

The time-domain behavior shown by the SW12 and SW15 is admirable. 20ms group delay is not breached until under 40Hz where it is too deep to make an audible difference. Starke Sound seems to have used 1 cycle as a target at which to keep group delay under. The rise in lower frequency group delay seen here stems from the filters used to equalize the response. If Starke Sound relaxed these filters, the subs would have had a more traditional sealed sub response shape meaning less deep bass until the sub has reached its limits. Starke Sound has found a good balance that keeps things quick in the more audible ranges while exchanging delay for more output where delay no longer carries as much of an audible penalty. The bottom line here is that these subs give the users nothing to worry about if they want a “fast” sub. These measurements demonstrate very good reaction times, and that is in line with my own listening experience with the SW subs.

Conclusion

SW15 outside hero.jpgBefore bringing this review to a close, I will briefly go over the strengths and weaknesses of the product under review, and, as always, I will start with the weaknesses since I am the kind of person who wants to hear the bad news first. The good news is that there isn’t much bad news about the Starke Sound SW12 and SW15 subwoofers. My only complaint is that when the SW12 is pushed very hard, it is not prevented from making some fairly distressful noises. It might have been better to use some somewhat stricter filters to inhibit that behavior, although that might have come at the expense of a bit of output and extension. Many owners probably won’t push the sub that hard, but if you crank the volume up on some content that has very deep bass, the SW12 might audibly complain about that.

Aside from the SW12’s behavior at its performance limits, I did not find any significant shortcomings with the SW subs. Their performance, on the whole, is good, especially in deep bass for sealed subs at their price point. Their deep bass headroom is needed given the shape of their frequency response which is weighted a bit more the low-end than most sealed subwoofers. The time-domain behavior is careful not to exceed a cycle of delay despite the shaped response. These characteristics make them a great choice for movies or music, and I enjoyed the subs with everything that I listened to. SW12 hero angle2.jpg

The $200 price increase from the SW12 to the SW15 is a worthwhile step-up as you're getting 50% more subwoofer performance for only 25% more cost.

Outside of the performance, these subs look fine and are not enormous, so they are good choices where size and aesthetics preclude large ported options. They are not back-breakingly heavy either, and that carries a much greater advantage than most people realize. Being able to move the sub around without it turning into a major logistical challenge is useful for when you are looking for optimal placement for sound in-room or are looking to relocate the sub for any other reason. One of the major draws of the Starke Sound SW subs is the pricing. These are very affordable subs given their spec set, and Starke Sound’s aggressive pricing indicates that they mean business in this market.

One thing I would say is that if you are able to make the jump from the SW12 to the SW15, it is a well-worthwhile step up. For only $200 more, you are getting significantly more subwoofer, not just in size but also in performance. Going by the average of the burst test data, you get about 50% more subwoofer performance for only 25% more cost. The SW15 was also able to keep its cool better when pushed hard. The SW12 is a fine sub for circumstances that need a smaller size, and it does pack a real punch for the amount of space that it uses, so if you can not accommodate the larger SW15, the SW12 can still dish out a nice bass sound for your system.

Starke logo2.jpg

The SW12 and SW15 subwoofers can be purchased from Starke Sound directly. They come with a 3-year warranty as well as a 30-day trial period. If you are not happy with the sub, Starke Sound will arrange for free return shipping, so buyers have nothing to lose by giving these subs a try. Anyone looking for an affordable, no-nonsense sealed sub is certain to be quite happy with these subwoofers, and I doubt that Starke Sound will be seeing many returns of these. 

 

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

  • StarStarStarStarStar — Excellent
  • StarStarStarStar — Very Good
  • StarStarStar — Good
  • StarStar — Fair
  • Star — Poor
MetricRating
Bass ExtensionStarStarStarStar
Bass AccuracyStarStarStarStar
Build QualityStarStarStarStar
Fit and FinishStarStarStarStar
Ergonomics & UsabilityStarStarStarStar
FeaturesStarStarStar
Dynamic RangeStarStarStarStar
PerformanceStarStarStarStar
ValueStarStarStarStar
Attached Files
About the author:

James Larson is Audioholics' primary loudspeaker and subwoofer reviewer on account of his deep knowledge of loudspeaker functioning and performance and also his overall enthusiasm toward moving the state of audio science forward.

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Recent Forum Posts:

Jshaw81 posts on February 13, 2022 14:27
Boomzilla, post: 1538997, member: 61571
With a Starke Sound SW-15 on order, I'm wondering if the DSP-LF unit from Parts-Express might be able to flatten the sub's frequency response? Obviously, Starke has used some built-in, plate-amp DSP already to obtain the curve they're producing from this sub but my use of the DSP-LF wouldn't be anything extreme. What I'd want would be to remove the bulge in the frequency response curve between 90Hz. and 20Hz. I don't feel any need to raise the curve below 20Hz. It would seem to me that, in theory at least, such DSP would possibly reduce distortion and make the response more linear?

I also have a question on where to locate the DSP-LF in my signal chain. My preamp offers bass management, so the sub signal will be attenuated at 12dB/octave above 90Hz. I could insert the DSP-LF immediately after the analog output of the preamp, then feed the signal to my wireless transmitter, and then run the wireless receiver directly into the sub. Alternately, I could run the preamp output directly into the wireless transmitter and insert the DSP-LF between the wireless receiver and the sub. Regardless of location, the DSP-LF will introduce another set of A-D / D-A converters between the preamp and the sub. So questions:

1. Will the improvement in frequency response achieved with the DSP-LF unit be worth the added distortion added by the unit's A-D / D-A converters?

2. Is there any advantage to locating the DSP-LF between the preamp and the wireless sub transmitter vs. between the wireless sub receiver and the sub?

Factoids that may inform potential answers:

I do not play loudly. Average listening level is from 60-70dB.
My room has acoustical treatment including absorbers, diffusers, and although there are no traps, every corner of the room is vented to other areas of the house
There are no prominent standing waves, and those that do exist, the DSP-LF unit has successfully attenuated
I primarily listen to music, not movies, and want my system balanced for music first
Associated equipment:

Mac mini running Roon
Emotiva Big Ego+ DAC
Emotiva PT1 preamplifier
Emotiva PA-1 mono power amps or Crown PSA-2 power amp or Black Ice Audio F22 tube amp or Heathkit SA-3 modified tube power amps
Klipsch RP-600m speakers (modified with internal damping materials)
I have two of those subs in order. Can’t wait to listen to them. I would probably get the subs and listen to them before spending any money on them.
Boomzilla posts on February 11, 2022 14:01
With a Starke Sound SW-15 on order, I'm wondering if the DSP-LF unit from Parts-Express might be able to flatten the sub's frequency response? Obviously, Starke has used some built-in, plate-amp DSP already to obtain the curve they're producing from this sub but my use of the DSP-LF wouldn't be anything extreme. What I'd want would be to remove the bulge in the frequency response curve between 90Hz. and 20Hz. I don't feel any need to raise the curve below 20Hz. It would seem to me that, in theory at least, such DSP would possibly reduce distortion and make the response more linear?

I also have a question on where to locate the DSP-LF in my signal chain. My preamp offers bass management, so the sub signal will be attenuated at 12dB/octave above 90Hz. I could insert the DSP-LF immediately after the analog output of the preamp, then feed the signal to my wireless transmitter, and then run the wireless receiver directly into the sub. Alternately, I could run the preamp output directly into the wireless transmitter and insert the DSP-LF between the wireless receiver and the sub. Regardless of location, the DSP-LF will introduce another set of A-D / D-A converters between the preamp and the sub. So questions:

1. Will the improvement in frequency response achieved with the DSP-LF unit be worth the added distortion added by the unit's A-D / D-A converters?

2. Is there any advantage to locating the DSP-LF between the preamp and the wireless sub transmitter vs. between the wireless sub receiver and the sub?

Factoids that may inform potential answers:

I do not play loudly. Average listening level is from 60-70dB.
My room has acoustical treatment including absorbers, diffusers, and although there are no traps, every corner of the room is vented to other areas of the house
There are no prominent standing waves, and those that do exist, the DSP-LF unit has successfully attenuated
I primarily listen to music, not movies, and want my system balanced for music first
Associated equipment:

Mac mini running Roon
Emotiva Big Ego+ DAC
Emotiva PT1 preamplifier
Emotiva PA-1 mono power amps or Crown PSA-2 power amp or Black Ice Audio F22 tube amp or Heathkit SA-3 modified tube power amps
Klipsch RP-600m speakers (modified with internal damping materials)
Eppie posts on December 02, 2021 12:04
shadyJ, post: 1521030, member: 20472
The 15" is now marked down to $539! That is a massive discount and well worth the money for that sub. That has to be the best deal going for sealed subs at the moment.
The free shipping applies to Canada too, which is a nice bonus.
shadyJ posts on December 01, 2021 14:53
The 15" is now marked down to $539! That is a massive discount and well worth the money for that sub. That has to be the best deal going for sealed subs at the moment.
shadyJ posts on November 05, 2021 00:32
CajunLB, post: 1514123, member: 89809
These subs are on Black Friday sale for 489/629 for the 12/15” models.
Somehow I missed this before. $629 is a ridiculously good price for the SW15. They really should be flying at that price. It's a good basic sealed 15".
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