Car Bass System Planner

Car Audio · System Planner

Plan your bass before you buy

Three choices — the car, the subs, the power — and you'll see how loud and how deep the system will actually play, plus exactly where every dB comes from. Then open the tuning sections to dial it in.

1 · The car

Pick the body style. This sets the interior size and how well the cabin seals — which is most of the bass story in a car.

In plain terms Your cabin is a sealed subwoofer box you sit inside. The tighter it seals, the more the subs pressurize it and the more free low-end you get — that's cabin gain. A hatchback holds pressure like a capped bottle; a convertible leaks it like a bottle with no cap.

2 · The subwoofers

How much cone you're moving, and what kind of box it lives in.

In plain terms Cone area is your paddle in the water: more paddle moves more air, and moving air is loudness. Two 12s beat one 15 on area. The enclosure is the leverage on that paddle — ported trades some depth for extra output in its sweet spot, sealed digs deepest and stays tight.
Driver & box tuning Fs is the note the cone naturally rings at, like a tuning fork — lower Fs, deeper reach. Qtc is how firm the sealed box's grip on that ringing is: low Qtc is a tight grip (flat, deep, accurate), high Qtc lets it bounce (punchy bump near resonance, boomier).
30 Hz

3 · The power

Amplifier power to the subs (RMS, not peak).

In plain terms Watts work like an earthquake scale — logarithmic. Doubling power buys you only +3 dB, and it takes ten times the power to sound twice as loud. That's why cone area and cabin gain are cheaper loudness than watts.
600 W

Predicted output · how loud it plays

— dB SPL

quiet 110strong 130extreme 150+

Where the loudness comes from

4 · Tune it

optional — open what you need
Where the bass cancels in this car seats & placement▸
In plain terms Slosh water in a bathtub and some spots pile up while others sit dead still. Bass does the same thing in a cabin — standing waves. Red zones boom, blue zones are moving opposite, and the dark lines are the dead-still nulls. You want the seats out of the nulls.
60 Hz
Best place to mount the sub searches every spot▸
In plain terms Push a sub into a corner and every nearby surface helps it shove air — each close wall is worth a few dB, free. Position also decides which cabin waves it excites. This checks every location and firing direction and ranks them for smooth, strong bass at both seats.
Crossover & blend with the midbass handoff▸
In plain terms The crossover is a relay-race handoff: the sub carries the low notes, then passes the baton to the door speakers. If both runners are in stride (in phase), the handoff is seamless — the black line stays flat. If their timing is off, they fight each other and drop the baton: that's the dip. Delay, polarity, and the all-pass are how you fix the timing.

Slopes are Linkwitz-Riley: each side is −6 dB at its corner and they stay in phase, so a clean handoff sums back to flat — no dip, no bump.

Tune the handoff. Distance and polarity are what you set on the DSP; the all-pass is for a dip that delay alone won't close.

0 in · 0.00 ms delay
0.0 dB
bends phase with no level change, to slide a stubborn dip out
75 Hz
0.70
sub band midbass band overlap (cancellation risk)
How this calculator thinks glossary & assumptions▸
dB SPL
Sound pressure level. +3 dB means double the acoustic power (barely a step louder to the ear); +10 dB sounds about twice as loud. 110 dB is a rock concert, 130 dB is jackhammer-at-arm's-length, 150+ dB is competition-lane territory.
Cabin gain
Below roughly 80 Hz the bass wavelength gets longer than the car, so the sub stops making waves and starts pressurizing the whole cabin like a piston. Tighter cabin = more of this free boost, and it grows as you go lower.
Boundary loading
A cone near a wall, floor, or corner can't waste energy in that direction, so more of it goes into the cabin — roughly +3 dB per nearby surface. This is why trunk corners slam.
Fs & Qtc
Fs is the driver's natural resonance; the sealed box raises it to the system resonance Fc, and Qtc says how damped that resonance is. Qtc 0.707 is the textbook balance; lower digs deeper and tighter, higher trades depth for a punchy bump.
Standing waves / nulls
At each frequency the cabin's reflections add up in some spots and cancel in others. A null is a cancel spot — EQ can't fix it, only moving the sub or the seat can.
Linkwitz-Riley crossover
A crossover family where sub and midbass are each −6 dB at the corner and in phase with each other, so their sum is flat. Timing errors (the sub sitting farther back) break that phase match — that's what delay, polarity, and all-pass repair.
What it doesn't know
These are planning estimates built from cone area, power, box type, and cabin acoustics. Real numbers depend on the specific drivers, box build, and install quality — use this to compare options, then verify with a meter.