SVS Auto EQ Review: Does It Really Improve Bass Response?

What is SVS Auto EQ?

It’s been a long time coming, but SVS’s much-delayed Auto EQ automatic room correction system for compatible SVS subwoofers is finally here. SVS promised to have an automated equalization system back at the launch of the 17-Ultra  |Evolution Series in October of 2024. At launch, they said it wasn’t ready yet but would be soon. “Soon” can be a subjective term, so they can arguably be said to have made that time frame, at least in terms of geological time scales, so I will allow it. It is here now, so the question is, how well does it actually improve in-room bass response? With some of SVS’s latest 3000 R|Evolution Series subwoofers in-house, along with SVS’s optional calibration microphone, I decided to investigate.

Getting Started

SVS’s auto equalization system is a part of their smartphone control app that can be downloaded from any major app store. I downloaded the SVS Subwoofer Smartphone Control App from Google Play for my Android phone, but it can work on Apple’s iOS and Amazon’s Fire platforms as well. The app is free, but it will only work with 17-Ultra, 5000, and 3000 R|Evolution subwoofers; it is not backward compatible with older Series.

SVS has made running the app a very easy task. Simply start the app, select the device that you want to measure the subwoofer with, whether it be the optional SVS mic or your smartphone mic. If using a smartphone microphone, place the mic four inches away from the front of the sub, run through a test tone sweep, and then place the mic at the listening position and run another test tone. After that, the app processes the data and calibrates the sub. When using SVS’s microphone, the user can skip the step of recording a near-field response of the sub, since the software knows the characteristics of the microphone.

This is the easiest auto EQ system I have ever used. That must have been what caused SVS to take so long to get it going. They understood that most people who have receivers with auto EQ systems like Audyssey and YPAO seldom take the time to use them, likely because they can be a bit complicated, especially with the need for extra equipment like a separate microphone. SVS is the only one that lets you use a mic that most people have on their person all the time. That had to have taken a lot of time to get right.

When SVS announced that they were launching an auto EQ system for their subs, I wasn’t blown away because there are many auto EQ systems out there, even ones that come with subwoofer systems. However, the ability to use your smartphone mic for the calibration was what took me by surprise. When I read that, I had to think that it was extremely ambitious by SVS, almost to the point of insanity, because of how much microphones can vary between all the devices that the app can run on. How will they compensate for all of the different microphone responses in the wild?

The solution was actually fairly simple and obvious in hindsight. The first step in SVS’s auto EQ process, recording a test tone so close to the sub itself, is the app measuring the mic’s response. It can do this because it knows exactly how the sub is supposed to perform in that test tone sweep at such close proximity. Taking an acoustic measurement so close to the subwoofer itself can eliminate the room’s effects on the subwoofer. The app compares the response it knows it is supposed to be getting versus the one it is receiving from the device's microphone. Once it understands the microphone’s response, it can compensate for that and measure the room’s effect on the response with the listening position measurement. It’s a neat system, but my guess is that it is only effective for bass because of how little low frequencies are affected by objects that are not large and very dense.

The microphone that users can buy from SVS (for a very reasonable cost: $45 shipped at the time of this writing) should work better than the smartphone mic since the software should have deep familiarity with that mic’s response. Also, that mic should be of higher quality than typical smartphone microphones, especially for low-frequencies which is what this application centers on.

A Few Measurement Results

Just for reference, the above response is the SVS SB-3000 R|Evolution’s anechoic response. As usual, we see SVS’s usual near-ruler-flat response. It is a neutral response that will inevitably be damaged by the acoustics of typical domestic rooms.

I ran the measurement routine for a few different places in my bedroom and measured the before-and-after effects on the response of SVS’s Auto EQ system. What follows are some of the results. Please keep in mind for the following graphs that the response curves are separated for better visibility, and that the overall amplitude level is not actually changed by SVS's Auto EQ system.

The above graph is of frequency responses that correspond to position 1 in my room. The raw room response (the green curve) for that subwoofer placement was not great, although not unusually bad either. Without equalization, the response was just two dips centered around 57Hz and 95Hz along with some high Q spikiness above that range. Using the equalization from the smartphone’s microphone (the blue curve) helped flatten out the response a lot. The peaks around these dips have been reduced considerably, and we are left with a much more neutral response. Using SVS’s microphone for calibration (the brown curve), the response was flattened out even more. This is an excellent result and is proving to be one of the better systems I have used. The equalization system took down the peaks and managed to shore up the response around the 57Hz dip. The improvement it made wasn’t just a more neutral graph curve; it was also readily audible. I am astonished at how well it handled this task with just a smartphone mic, and of course, SVS’s mic was that much better.

What about Deep Bass?

The equalization did temper down the deep bass below 40Hz a bit. Many people do prefer a rising response in low frequencies, so if you don’t want a flat response all the way down, you can use SVS’s parametric equalizer to bring up the response in deep bass to your preference. Just keep in mind that boosting the deep bass can make subwoofers run into their excursion limits quickly, especially sealed subwoofers.

The above image shows what the SVS app measured the room response to be (in white), and it also shows the predicted improvements. The actual post-equalized response isn’t quite as picture-perfect as what the SVS app shows, but it was still a major improvement nonetheless. SVS’s predicted result is just a projection of what its equalization should produce. Many equalization programs depict a projected result, but rarely do they match the actual result. The only way to know for sure is to measure the corrected response, which no auto EQ systems do that I have seen.

Let’s try a couple of other subwoofer locations in the room to see what the app can do…

The unequalized room response for my next sub spot (the green curve) is pretty bad; it is basically just a low-Q null centered at 53Hz followed by a peak at 90Hz. The Auto EQ app had its work cut out for this one. With the phone microphone (the purple curve), the equalizer took down a lot of bass below 40Hz as well as trimming the peak at 90Hz. It also trimmed some upper bass peaks too. The result with the smartphone mic is not perfect but it is a definite improvement. Using the SVS microphone improved things even more. It relaxed the deep bass trim while flattening out the rest of the range. The 53Hz dip still remains, but there isn’t much an equalizer can do about that, but its severity has been lessened, and everything else has been made more neutral. The null can only really be addressed acoustically, so the thing to do at this point would be to add a subwoofer that shored up the dip. Even so, the sub sounded pretty good after equalization, particularly using the SVS calibration mic.

The above graph is from yet another subwoofer position in my room. This one is interesting because what we see in both the EQ’d and non-EQ’d responses is two narrow dips, one at 59Hz and another at around 110Hz. What the SVS Auto EQ app does here is what I would expect. It mostly just trims the responses outside of the nulls. The improvement that it yields is substantial. What is interesting here is that it can also tighten the dip from 45Hz to 50Hz a bit. Again, it seems to trim deep bass more from my smartphone microphone calibration than from the SVS microphone calibration. The SVS microphone calibration is superior to the smartphone mic calibration, but there is no surprise there since phone microphones are not usually the most high-fidelity devices.

The SVS equalization doesn’t try to shore up the nulls, thankfully. Trying to shore up the nulls would be a waste of energy since it would essentially be the subwoofer fighting its own acoustic reflection. The sub would be just dumping wattage into a black hole. This is what we advocate for a multiple-subwoofer setup: Use one sub to address the inevitable nulls left by the room response of the other sub.

Conclusion

SVS’s Auto EQ system turns out to be a pretty cool and effective equalization system that is a cinch to run. My guess is that a lot of people who may not bother with auto-equalization functions will actually run SVS’s Auto EQ because it is so easy. That being the case, one thing that SVS might want to stress is that it needs to be rerun every time the sub is moved to a new location. SVS does note that in the app, but it may pay to emphasize that fact a bit more. Audio enthusiasts will know that, but it isn’t something the general public will intuitively understand.

By making the equalization system able to be run on a smartphone alone, SVS has made an automated equalization system for everyone (or at least everyone who has an SVS subwoofer). I haven’t ever been convinced of the need for an app to control a subwoofer, since most subwoofer controls are something you set up once and then leave them be, but SVS has presented a good justification for a subwoofer control app since their Auto EQ system actually works and makes automated room correction so easy that anyone could do it within minutes. For those who really want to button down the response, I think investing in SVS’s calibration microphone is a good idea since it did yield a very tangible improvement over my smartphone mic. It has been a long wait for the SVS Auto EQ app, but I would say it was a worthwhile investment on SVS’s part, because this really does make a tangible improvement in the sub’s sound quality, and I am sure a lot of people will see that when they hear the changes it can make. Bravo SVS!