EMMA Sound Pressure League

The EMMA Sound Pressure League is made for those kinds of competitors who are interested in the maximum level of volume in their cars – not forgetting about a safe installation and neat appearance. To guarantee similar conditions and fairness to all competitors, the amount of subwoofers will be regulated in the following terms in all categories:

  • All the installed and connected woofers will be calculated as shown in the table below.
  • It is defined, that one 25cm=10” woofer will be counted as one woofer. Since not all people have 10”woofers installed, the following calculation key will be used.
Number of woofers Size of woofer Classification Circumference (No longer than)
1x 25cm =10” Equals 1 woofer 78,5cm
1x 30cm =12” Equals 2 woofers 94,2cm
3x 20cm = 8”/6”x9” Equals 2 woofers 62,8cm (per 8”)
1x 38cm =15” Equals 3 woofers 119,3cm
1x 46cm =18” Equals 4 woofers 144,4cm

Judging procedure for all ESPL classes:

  • Installation check according to the matrix.
  • Measurement with closed doors.
  • Measurement with open doors.


  • ESPL E-Category 2 Woofer
  • ESPL E-Category 4 Woofer
  • ESPL E-Category 8 Woofer
  • ESPL E-Category 16 Woofer
  • ESPL X Unlimited