engine sound simulator | Drone Hz, J-Pipe Length, Hear It

engine sound simulator | Drone Hz, J-Pipe Length, Hear It
Example of the result this page gives you

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How it works
  1. Enter your details in the free version below.
  2. See your result right away on this page.
  3. Need more? The full version adds what is listed under "What you get".

What you get: now vs after A/B with the same drive, garage of saved setups, record your run and download WAV, backup.

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Filled example (made-up): a V8 at 70 mph cruises at 2,178 rpm and drones at 145.2 Hz. A J-pipe cut with the room-air speed of sound (343 m/s) comes out 9.2 in too short and tunes to 202.7 Hz, so the $1,150 cat-back keeps droning at cruise. Type your own car below.

Engine sound apps play sounds; none tells you the note your car drones at on the highway. This page turns your speed, gears and tire into that note, plays it, and plays it again through the J-pipe that cancels it.

Your numbers

Your result

Cruise rpm in top gear-
Drone frequency (firing Hz = rpm x cylinders / 120)-
Speed of sound in your hot exhaust (m/s)-
J-pipe length for hot exhaust (in)-
J-pipe length cut with room air 343 m/s (in)-
Room-air pipe too short by (in)-
Room-air pipe actually tunes to (Hz)-
Exhaust money riding on the cut length ($)-

Everything updates as you type. Nothing is uploaded. This runs in your browser.

Hear it

Your engine note at cruise, synthesized from the firing frequency above (no recordings). Then switch the J-pipe and listen to the drone note drop out.

Stopped.

The rule inside

A 4-stroke engine fires each cylinder once every two turns, so the note is rpm × cylinders ÷ 120 Hz. A J-pipe is a closed side pipe one quarter of a wavelength long: length = speed of sound ÷ (4 × Hz). The speed of sound is √(γRT): it rises with gas temperature (NASA Glenn Research Center, “Speed of Sound”, read 2026-11-15), about 343 m/s in 20 °C air and about 480 m/s at 300 °C. Length is measured from the junction with no end correction; cut slightly long and trim.

Full version — $21 once: the Excel workbook with the same 12 live formulas plus the drone note and J-pipe length at 60 and 80 mph, to keep and compare your builds offline. Get the workbook

Get the full calculatorFull version: all tabs, your own file, works offline.

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Pro, $2.99 a month or $19.99 a year: now vs after A/B with the same drive, garage of saved setups, record your run and download WAV, backup.

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Example on the page: 70 mph × 3.21 × 0.67 × 336.13 ÷ 32.06 in = 1,578 rpm; on 315/70R17 tires with a 4.10 axle it is 1,881 rpm, and the speedometer reads 70 at a true 75 mph.

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Questions and answers

What does this page do?

Example: a made-up V8 at 70 mph cruises at 2,178 rpm and drones at 145.2 Hz; a J-pipe cut with the room-air speed of sound (343 m/s) comes out 9.2 in too short and tunes to 202.7 Hz, so the 1,150 dollar cat-back keeps droning.

Is it free?

Yes. The free version on this page works without an account. The full version ($2.99) adds: now vs after A/B with the same drive, garage of saved setups, record your run and download WAV, backup.

How do I use it?

1. Enter your details in the free version below. 2. See your result right away on this page. 3. Need more? The full version adds what is listed under "What you get".

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