SVS SoundPath Subwoofer Isolation Feet

Can Nothing in Home Theater Ever Be Easy?

As happens far too often, a recent change I made that was supposed to be a small, simple tweak to my home theater equipment wound up turning into a much more involved project and a major time-suck. At the end of it, I know a lot more about acoustical problems in my room, but I also came away thinking that perhaps ignorance was bliss.

When I built my home theater, I worked very hard to soundproof the room so that noise from my movie-watching wouldn’t disturb my wife (and later, my kids) upstairs. Nonetheless, as good as I was able to get it, 100% soundproofing is practically a pipe dream in a real home environment. Short of tearing the entire house down and rebuilding from scratch, I had to settle for “very good” rather than perfection. Deep bass sounds in particular are extremely difficult to stop and can travel all through a house no matter what you put in the way to block them. For most of the content I watch, my soundproofing does its job and my family never hears anything. However, loud, explosion-filled action movies can sometimes result in bass transmission and even rattling upstairs.

In addition to this problem, I have struggled to get even bass response in my theater room, even after upgrading to a very high-quality SVS subwoofer. This has more to do with room acoustics than with the subwoofer itself. Specifically, in doing measurements while playing bass sweep test tones, I noticed a dip around the 60 Hz range. This is apparently very common in many rooms.

I held no illusions of finding a quick (much less cheap) fix for either of these issues. I had basically resigned myself to dealing with them until I decided to give the SVS SoundPath Subwoofer Isolation System a try. The idea behind this so-called isolation system is that placing a subwoofer on a floor (which most people do) results in a lot of energy transmission into the floor, which consequently causes rattling and travels through other adjoining surfaces. By raising the subwoofer higher up off a floor, you reduce the amount of that energy waste. According to the product listing:

“The SVS SoundPath Subwoofer Isolation System works with nearly every subwoofer brand and model to improve bass performance while reducing floor and wall vibrations, noise artifacts and complaints from neighbors or roommates. De-coupling a subwoofer from the floor results in inherently tighter and cleaner sounding bass. It’s also the next best thing to sound-proofing and ideal for carpeted rooms, hardwood floors or any space where room rattles, buzzes or vibrations are present.”

Those are some awfully big claims for what amounts to a set of padded rubber feet. “The next best thing to sound-proofing”? Knowing how difficult soundproofing actually is, that’s pretty hard to swallow. Even so, the product is not terribly expensive and I figured that I had little to lose in trying it. I can’t think of any scenario where using these would hurt my sound quality. Worst case, I’d notice no difference.

Jumping Down the Rabbit Hole

When I received the SoundPath feet, they were extremely easy to install and took barely a minute to attach. I wish I could say that there was nothing more to it and I experienced an immediate improvement in both bass quality and soundproofing, but that’s not quite what happened. Making one small change quickly spiraled into needing many more changes.

First off, any change to audio equipment like this, even as little as moving a speaker or subwoofer, requires a fresh Audyssey calibration to ensure that my automated room EQ processing can account for the new variables. As I explained earlier this year, my convoluted three-AVR Dolby Atmos setup makes running Audyssey much more complicated than an average user.

Having gone through that process, I ran some more bass sweep tones. Sadly, the 60 Hz dip was still present. No surprise, these little feet couldn’t fix that – not that I expected them to. The manufacturer made no such claims, and I knew that, realistically, raising the subwoofer up a couple inches couldn’t correct the root of the problem.

At this point, I basically abandoned my original interest in the SoundPath feet and became obsessed with that 60 Hz dip. I conversed extensively with a friend who’s an audio expert and came to the realization that this dip was caused by: 1) my subwoofer placement, and 2) the location of my primary listening position. Forget anything else I may have had in mind, now I needed to fix that.

Seating Location

My home theater room is fairly long, and when I originally installed my projection screen and equipment, I placed my recliners at roughly a halfway distance so that I could use the space behind them as an office area.

Home Theater Overhead View

It turns out that this left the seats very close to a room mode – basically a null point in the soundwave where certain bass note frequencies cancel out. Even though my subwoofer was producing those notes, they’re not audible in that position. My first step in correcting this was to move my seats forward a little bit to get them further away from the mode. Unfortunately, moving them really far forward where the bass was optimal would essentially leave me with my face pressed up to the screen. It’d also be pretty lousy for the sound from all my other speakers. I did my best to find a compromise, but nothing I tried was quite perfect.

Subwoofers

Next, I decided to pull my second subwoofer (the older one from before my upgrade) back into service for a dual-sub configuration. Ideally, when running multiple subwoofers, they ought to be identical, or at least have equivalent specs. I can’t do that at the moment. I can’t afford another new sub, so I have to make do with what I have and hope for the best.

After I purchased my SVS subwoofer, I did a Sub Crawl and settled on putting it near the front left corner of the room (Position 1 below).

Original Subwoofer Location

When using two subwoofers, the typical advice is to place them opposite each other, either with one in the center of the front wall and one in the center of the back wall, or in opposite diagonal corners. I started by trying the latter approach. Due to my furniture and other room constraints, the closest I could get were these spots:

Dual Subwoofer Locations Option 1

Unfortunately, that neither sounded nor measured very good, probably because the first subwoofer isn’t actually in the exact front corner, and my room is irregularly shaped with the back half being a narrower width than the front half. Whatever the reason, it didn’t work and I’d have to try something else.

Sadly, I can’t put a subwoofer in the center of my back wall because I have a desk there (and nowhere it can be moved to). That’s out of the question. After lengthy discussions and math calculations, what I decided to try was placing one subwoofer in the center of the front wall, and the other right in the middle of the mode, behind my seats in the approximate center of the room.

Dual Subwoofer Locations Option 2

The theory here is that placing Subwoofer 2 right in the null will cancel out the mode, allowing Subwoofer 1 to do its job better. Much of the math involved is above my head, but this was recommended as the most promising option.

Is It Any Better Now?

My results with this new setup are mixed, as I feared. On the plus side, bass sweeps measure a little better in the 60 Hz range. I still have a little dip there, but much less of one. Using two subwoofers has largely flattened that out. This is good news.

The bad news is that I have basically no bass activity below 30 Hz now. Whether that’s due to my room mode issues or the fact that one of my subwoofers is technically inferior to the other (or some combination of the two problems), I can’t say for sure. What it comes to is that I’m lacking infrasonic bass at the moment, which is a bummer.

Fortunately, not every movie soundtrack incorporates bass that low, and almost no TV shows do. The majority of what I watch in my home theater these days is TV, so I’m not having an immediate crisis to upgrade my subwoofers and change my configuration around again. On balance, fixing the 60 Hz dip is probably more important than anything below 30 Hz. A lot more bass activity happens in that higher range.

Nevertheless, I’m disappointed. More work is needed. Eventually, I’m going to have to save up and replace my secondary subwoofer with another at least as good as my primary sub, and I’ll probably need to do a lot more experimentation with where I place them.

What About the Feet?

As for the original tweak that started this whole process, I honestly don’t think I can give a fair review of the SoundPath isolation feet. I changed too many other variables in my room to know how much (if at all) the new subwoofer feet affected my results or improved my sound quality. It wouldn’t be fair of me to write them off completely, but what I can say is that I did not find them to be a miracle cure. Bass issues resulting from room acoustics are too complex for any simple fix, and true soundproofing requires a lot more effort and expense than just decoupling one subwoofer from the floor.

Ironically, moving my primary subwoofer to the front of my home theater room may have resulted in slightly more bass transmission upstairs, because the front wall it sits next to now runs directly up to the middle of my living room.

I think I’ll keep the feet in place, though. They aren’t hurting anything. If they do help even a small amount, I might as well leave them be.

17 comments

  1. Plissken99

    I might be further muddying the waters here, but have you considered trying a down firing subwoofer as your secondary? I used to have the SVS PB2+, which had dual 12″ down firing woofers, it was a beast. A down firing sub can add a tactile bass feel, in an odd room like yours it may fix things as well.

    • Josh Zyber
      Author

      I haven’t tried that, but I’m not sure it would make a difference. The problem is the room mode, which can’t be overcome just by throwing more power at it. The only ways to cancel a null are either to put a subwoofer directly in the center of it, or to place two subwoofers on opposite sides of it.

    • This may sound weird, but I actually buy down firing subs BECAUSE I have hardwood. I am actually trying to use the reflections as an advantage – the key here is that I don’t have to turn the sub as loud. I’m in an older hosue with crapey electrical wiring –
      watching something with a lot of bass results in overloads and flipping circuits. Lucky for me, whoever wired the house has like every outlet on a different circuit (I don’t think this was done on purpose, I think the person was just an idiot – its obvious that many of the outlets were added later). The advantage to this is that two extension cords lets my home theater be on three different circuit breakers, which helps. Power conditioner / battery on the amp and players and consoles, seperate UPS on a different circuit for projector, routers, modems and switches, and a seperate circuit for sub, powered recliners and lighting. However, even with doing all of this, I still have issues with a ton of bass. Downfiring means using the hardwood’s reflective surface to help carry the bass, and it works remarkably well.

      Of course, this works great for me, but it may work awful for you

  2. Mark Pitts

    Do you mean a room “node”?

    Have you considered a nearfield subwoofer set to be out of phase with the main subwoofer?

  3. Csm101

    Have you tried placing your main sub at the left wall between the black shelf and your seating facing toward the room?

  4. Derek

    Trying moving sub 1 to/towards front left corner of room. You might gain back a bit of low end with the corner reinforcement.

  5. Csm101

    I was told that the isolation feet work better on wood floors or upstairs if the top portion of the house is made of wood. If your basement is made of concrete, I don’t think it would make a difference. When I first started inquiring about SVS subs, I’m pretty sure it was Ed Mullen who told me not to bother with the isolation feet if my floor was poured concrete. You know you can always call them and see if they have any other ideas that you haven’t thought of.

  6. Ross

    I ran into a similar issue when I bought my SVS as well. I ran it with 2 Paradigm’s and had the same issue. I bought the Auralex sub riser and removed the Paradigms. They couldn’t keep up with the SVS. My bass now sounds and feels amazing. I also have concrete floors. I put a large shag rug in between my soundstage and couch and that really helped as well. I had 24 Auralex panels on my walls and ceiling for the better part of a year. I removed them because I didn’t like the look and I wanted to paint the side walls and ceiling black. I ran Audyssey to see how the difference was without them and I noticed that I liked the bass much more without the panels so I left them off. Also looks better now.

    Honestly my home theatre obsession has become a pain. I finally have my sound right and now I’m having a big question on calibrating my projector. After painting my walls and ceiling black it has improved the image greatly but since my projectors bulb is at 2100 hours and calibrated the image is becoming dim. I feel like I’m constantly calibrating with my light meter and I fear my meter which is an X-Rite i1 Pro is inadequate at reading the low end of grayscale. When I switch to the uncalibrated THX mode it looks much better and vivid. The image has much more depth and deeper blacks as well. I’m envious of my friends who buy TV’s and don’t fuss and enjoy them.

  7. Scott David

    You may have already tried this but how about an isolation platform for your sub? I have one from Auralex, that I use now, even though it’s placed on carpet, while living on the first floor. I got it for use in my previous apt where I lived on the third floor. Never had any complaints.

    • Josh Zyber
      Author

      That’s basically what the SoundPath feet are supposed to do. I’m not saying they didn’t work, just that they didn’t completely solve the problem in this specific case.

  8. The sub crawl that you linked to is an interesting thing I never thought to do, but it is so obvious. I tend to think “The sub is non-directional, it doesn’t matter where you put it”, but never really thought much about reflection. I may try this and see if there is somewhere I can get better sound at, Actually, after reading this article, it seems like the best place for a sub would be under my coffee table, but I think my current sub is too big to fit there.

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