Subwoofer Placement Calculator

There is no single right spot, which is why a tool like this exists. A subwoofer's output combines with the reflections bouncing between your walls, floor and ceiling, and that combination is different at every position in the room — for the subwoofer and for each seat.

Corners are the usual starting point because a corner couples into every room mode at once, giving you the most output for the least power. That is not the same as the smoothest result: exciting every mode strongly can make peaks and nulls more pronounced. Along a wall, roughly a quarter or a third of the way along, often trades a little output for a flatter response.

The honest answer is that it depends on the dimensions of your room and where people actually sit. Set your room and seats above, then move the subwoofers and watch the seat-to-seat spread.

Because of room modes. At low frequencies the sound wave is comparable in size to the room itself, so it reflects off the walls and interferes with itself. In some places the reflections add and you get a peak; in others they cancel and you get a null.

Those peaks and nulls sit at fixed positions in the room. A seat parked in a null at 45Hz will sound thin no matter how much you turn up the subwoofer, while the seat beside it may be booming at the same frequency. Differences of 10 to 20dB between seats in the same row are entirely normal in an untreated rectangular room.

This is the number the tool reports as spread — the gap between the best and worst seat.

If more than one person watches at a time, usually yes — and it is the single most effective change available to you.

One subwoofer can be positioned to sound excellent at one seat. It cannot be positioned to sound the same at four seats, because the peaks and nulls are fixed in space. Two or four subwoofers placed so their modal patterns partly cancel each other flatten the differences across the whole seating area.

The research most people cite here found that multiple subwoofers at wall midpoints or in opposite corners dramatically reduce seat-to-seat variation. Try the presets above: switch between one subwoofer and the four-corner arrangement and watch what happens to the spread.

It can fix a lot, but not this specific problem. EQ is applied to the signal, so every seat receives the same correction. If one seat sits in a null at 45Hz and another has a peak at the same frequency, cutting 45Hz helps the second seat and makes the first one worse.

A null is also missing energy rather than excess energy. Boosting it burns amplifier headroom and pushes the driver hard for very little audible gain, because the cancellation is still happening in the room.

The order that works is placement first, then room correction. Get the seats agreeing with each other physically, then let correction refine what remains. That is why we treat placement and calibration as two separate steps rather than one.

It is the best place for output, and often a good place, but it is not automatically the best place for even bass.

A corner sits at a pressure maximum for every room mode, so the subwoofer couples efficiently into all of them — typically several dB more output than the same subwoofer mid-wall. If you are short on headroom, that matters.

The trade-off is that exciting every mode strongly tends to make the peaks and nulls more pronounced across the room. With multiple subwoofers, positions that deliberately cancel each other's modal patterns usually beat four corners on evenness. Model both and compare the spread.

Yes, though usually less than moving it horizontally. Height determines how the subwoofer couples into the vertical modes between your floor and ceiling.

A subwoofer on the floor sits at a pressure maximum for every vertical mode, which is efficient. Lifting it onto a riser moves it up toward the null of the first vertical mode, which can either help or hurt depending on where your ears sit relative to that same mode.

The tool has a riser height field on each subwoofer for this reason, and seated ear height on each row, so the vertical geometry is modeled rather than assumed.

It is a good guide to relative differences and not a substitute for measuring. The model sums rigid-wall room modes up to third order with adjustable damping, which captures the behavior that dominates below roughly 100Hz in a rectangular room.

What it does not know about is your actual room: doorways and openings, wall construction and how much energy passes through rather than reflecting, furniture, and any existing acoustic treatment. It reports relative levels between seats, not absolute SPL, and it assumes a closed rectangular box.

Use it to compare arrangements and narrow the options before moving anything heavy. Confirm the result with measurements in the actual room.

A resonance created by sound reflecting between two opposite surfaces. When half a wavelength fits exactly between two walls, the reflection reinforces the original wave and the room rings at that frequency.

Every pair of surfaces produces its own series: length, width and height, plus combinations involving several surfaces at once. A 13.5 by 21 by 9ft room has its lowest mode near 27Hz, right in the range a subwoofer covers, which is why bass behaves so differently from the rest of the spectrum.

Expand "Room modes below 100Hz" above to see the ones your dimensions produce.