Short version

The subwoofer crawl works, but it's still a band-aid. You put the sub in your seat, then crawl the floor listening for the spot where the bass stays even, not loudest, and that's where the sub goes. It's free and better than guessing, but it only helps one seat, and it moves the holes in your bass around instead of removing them. If you can put a second matched subwoofer in the room instead, do that and skip the crawl entirely.

Clever, but still a band-aid

The subwoofer crawl works, but it's still a band-aid. It's a clever way to find the least-bad spot for ONE subwoofer. If one sub is what you have, go for it. If you can put a second matched subwoofer in that room instead, do that and skip the crawl entirely.

Whoever thought of it, it's brilliant! I want to say that up front, because the rest of this reads like I am down on the technique and I am not. I am down on the situation that makes you need it.

What the crawl actually is

You take your subwoofer and you set it up in the seat where you sit most of the time. Then you play content and you crawl around on the floor, listening, looking for the best possible response. Wherever the bass sounds best down there is where the sub goes.

It sounds backwards the first time you hear it. It's not.

Bass between two points in a room behaves the same in both directions, like a mirror. Put the sub where your head will be, then put your head where the sub will be, and what you hear on the floor is what you'll hear in the chair once you swap them back. That's the whole trick, and it's the reason a crawl beats guessing.

It also costs you nothing but an afternoon, which is more than I can say for most of the advice out there.

How to do it

1. Pick content you know cold. Something with steady, repeating bass you've heard a hundred times. Your favorite scene, your favorite track. You're comparing spots, not auditioning music, so the same thirty seconds on repeat is perfect.

1. Put the sub in your main seat. Up on the cushion, facing the room the way it normally would. If it's a big ported sub, get a second person, and DON'T wreck your couch or your back over this.

1. Set a moderate volume, then leave the volume alone. Every time you touch that knob you throw out your comparison.

1. Get on the floor and crawl. Along the front wall, along the side walls, into the corners, out along the likely spots. Keep your ear down at the height the subwoofer's driver will sit at.

1. Listen for even, not for loud. Corners will be the loudest place in the room almost every time. Loudest is not best. You are hunting for the spot where the bass stays full and stays THERE as the notes change, instead of booming on one note and vanishing on the next.

1. Mark the winner, put the sub there, and rerun your room correction. You just moved a speaker, so everything your receiver measured before is out of date.

Then adjust the gain by ear. Always trust your ears.

What the crawl won't do for you

Here's the part that gets left out of most other write-ups of this.

The reason you're crawling in the first place is because of the standing wave effect. Bass waves are long, they bounce off your walls, and they run into themselves. Where they line up you get a loud spot. When they cancel you get a dead spot, and the dead spots for one frequency are in completely DIFFERENT places than the dead spots for another frequency. That's the pattern I call Swiss Cheese Bass, and a single subwoofer always produces it. It's physics, not a brand problem.

So you crawl around with your favorite content playing, and your favorite content really hits in one spot, and you put the subwoofer there. That's great. You're still missing other frequencies that are being cancelled out, because you're running a single.

You didn't remove the holes. You moved them, and you picked which ones you can live with.

And it only works for that seat. Move one seat over, two seats over, and the bass is different again. If you're the only one who ever watches anything in that room, that's great, but you're still missing some bass in your spot too. If you have a couch full of people, you just "optimized" one cushion, as best as it can be optimized. It's still not a "sweet spot", it's just slightly better than it was.

Why I don't bother

I tried the crawl years ago, and I was never really satisfied with the results. Since I've been running this channel I've been running dual subwoofers, and dual subs eliminated the need to even bother with a crawl for me. Any time I've run a single sub, my reaction was to turn it off in favor of matching duals, even if they're a quarter of the cost. It's not going to work. You can't "unhear" correct bass.

This is why I only review matching dual subwoofers. It's my goal to tell you how a subwoofer actually sounds and how it performs, and I can't do that with a single sub sitting in a standing wave. It's quite frankly impossible, physics wise. Whatever that sub does well, the room is hiding a LOT of it from me.

Two subs in two different places excite the room differently, so one of them tends to put output right where the other one has a hole; that's a simplistic way to look at it. You're not chasing the least-bad chair anymore. I've had people listen to my system and it's never what they expected, because they can hear ALL of the bass, as deep as they can hear! It's also MUCH more comfortable and clear, with a LOT more sound energy in the room, even at lower volume. That's a different experience from the norm, and the way you get it is dual deep subwoofers in your room.

The problem nobody warns you about

A crawl tells you where the subwoofer wants to go. Your house gets a vote too.

My theater is also my living room, so I can't go sticking subs wherever I like. When I ran one big sub, it only fit in one place, the corner, and a sub crawl was pointless. It could only go one place. On another setup I could move the sub inside about a four foot footprint and that was it, for aesthetic reasons that were not negotiable. Partner Acceptance Factor is real, and it's a bigger constraint than most of the internet admits.

So before you haul a sixty pound, or worse a 200 pound sub onto the couch, walk the room and be honest about where that cabinet is actually allowed to live. If the honest answer is one or two spots, you do not need a crawl. You need to decide between them, and then get as much of your response back as you can with speaker distance settings and a careful crossover instead. Or go dual and easily fix the problem, while gaining clarity, tightness, comfort, and impact.

If a single sub is what you have right now

Do the crawl. It's better than nothing, I'll give it that, and it's free.

Then set your distance properly, because on a single sub the distance setting is doing more work than people realize.

And put "second matching sub" on the list ahead of every other upgrade you are considering. Not a bigger sub, unless your subwoofer is not a true deep bass subwoofer, then plan for 2 matching deep bass subs.

I ran a genuinely excellent big 15" ported sub for a year and a half, and then put two of the most affordable 10" ported subs SVS made at the time up against it for about the same money, and the pair resolved my dead spots. Brute force in one sub will not overcome the need for two. I wrote that whole comparison up on 1 Big Sub VS 2 Smaller Subs.

Two matched subwoofers is the sweet spot. Not one, not four. 2 more explosive subs are more impressive than 4 less explosive subs. At a minimum, dual PB-1000 Pro's or any matching dual ported SVS subwoofers. That's the kind of bass I can easily vouch for. Matching matters, so don't pair a big one with a little one, or a sealed one with a ported one. The pair follows the weaker sub.

Where to put the two of them is its own conversation, and the short version is that it's a much more forgiving problem than placing one. My preference is inboard of my left and right speakers for the most impact and clarity. Corner loading degrades both for more output, which you could get from a gain increase on the subwoofer itself. My Best Subwoofers List gives you a brief overview for each subwoofer.

My actual advice on the subwoofer crawl

The blunt advice I'd give to anyone that I truly care about: Don't put yourself in a situation where you have to use it.

I don't ever anticipate needing to. It's just something to avoid. It's a cheap band-aid, it's a compromise, and you're not going to get great bass response if you find yourself needing to do it. If you have to do it, cool, it'll be better than not. Just know what you're settling for while you're down there on the carpet.

Hopefully that helps, and thanks for stopping by,

Ryan B.

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