KOTR Sound Off


1: Hearing Protection is provided & is advised to be worn during the SPL testing process.
2: Disclaimer for damage against equipment & personal injury due to exposure of high SPL levels MUST be signed before any test is to be carried out.
3: Engines can be left running / idling - The accelerator is allowed to be pressed if the participant feels that this may help to increase his / her score, whilst playing a test tone.

4: All SPL categories can have as much bass amps - speakers etc that will fit into the available space of the category that their system falls into.
4a: Batteries can be positioned anywhere throughout the vehicle - Amplifiers that are not used for powering subwoofers can also be positioned anywhere throughout the vehicle.
5: All categories can have as much sound deadening / strengthening mods as the owner wishes.
6: No restrictions on any type of playback equipment - Cd Players , DVD Players, I-POD, USB, SD, Hard Drives etc can all be used.
7: There are normally no restrictions on the amount of time it takes to carry out an SPL test.
7a:However if the tests are being carried out in an open day / event where prizes or trophies are being given out or there are many people waiting to be tested (Over 15), then there is an advised 30sec time limit for each frequency attempt.
8: The testing is normally carried out by using an officially available test CD or a digital form of test CD.
8a: However if the participant feels that their system can play certain frequencies louder by actually playing music instead of the test tones that are provided on a Test CD etc then they are free to try using that method.
9: The use of external battery supplies and power sources which are outside the vehicle are currently prohibited.
9a: Battery trays are allowed however they must be positioned within the inside of the vehicle - The only exception is Rule 9b.
9b: Build downs to stored batteries from below the floor pan are allowed provided the tray has been constructed in a safe manner and also completely seals the batteries from the outside of the vehicle - rendering the battery tray as part of the internal structure of the vehicle.
10: More than one person can be inside the vehicle whilst testing.
11: The SPL sensor can be placed on either the passenger or drivers head rests.
11a: The SPL sensor, once positioned on passengers or drivers head rest must remain in that position throughout the SPL testing process.
11b: You cannot swap the positions mid testing but you can re-test with the sensor on a different side.
Any higher scores can be taken as the participants systems score.
This benefits system that are built for other SPL formats as the port is usually to one side of the vehicle.


1: Any combination of doors, windows or sunroofs, even the boot, can be opened or closed to try & and achieve a higher SPL score.
3: Doors, windows, sunroofs, roofs and body panels etc can be pushed against to try & achieve a higher score.

This is where two subs are mounted in such a way as to provide extra motor strength but still using the same cone area as a normal subwoofer.
Clam shell method is the most popular method of mounting in this way.
Any system which participates using this type of set up will have each clamshelled pair of subwoofers classed as one Subwoofer As the new rules for 2011 will be based on cone area and power...


1: The standard SPL test does not allow for any kind of port or box alterations in which to increase specific frequencies.

The idea of this test is to see just how well your normal, Sound system performs at playing low bass.


1: If you manage to beat your systems previous best score at any frequency, with EXACTLY the same BASS BOX SYSTEM - PORT CONFIGURATION and MAKE of SUBWOOFER set up that you used before, then that score will be upgraded and your overall score updated to suit.