Acoustifoam Users Guide - Part 1
Part 1: Picking the right size
If you use a bar style shoulder rest with side clamps I recommend getting 2 Acoustifoams to match the support of your old shoulder rest.
There are 11 different sizes for the Acoustifoam. The shortest, size #2, is 7/16”. Each size increases it's height by 1/8”. For example, size #3 is 9/16”. See the chart below for the full list.
| Shoulder Rest Size | Height of Acoustifoam |
| Size 2 Shoulder Rest | 7/16" |
| Size 3 Shoulder Rest | 9/16" |
| Size 4 Shoulder Rest | 11/16" |
| Size 5 Shoulder Rest | 13/16" |
| Size 6 Shoulder Rest | 15/16" |
| Size 7 Shoulder Rest | 1 1/16" |
| Size 8 Shoulder Rest | 1 3/16" |
| Size 9 Shoulder Rest | 1 5/16" |
| Size 10 Shoulder Rest | 1 7/16" |
| Size 12 Shoulder Rest | 1 11/16" |
| Size 14 Shoulder Rest | 1 13/16" |
The best way to estimate the correct size is to measure the height of your current shoulder rest from the point where it touches the surface of the instrument to the point where it touches your body. Take this measurement from the left side (the side which touches the chin) and then the right side (the side closest to your bow).
Find two Acoustifoams whose height comes closest to matching the measurements you took without going over. For example, if the right side was 1½” and the left side was 1 3/16” inches you would select a size #10 and #8.
If you use a sponge for a shoulder rest then I recommend getting one Acoustifoam to replace it.
Measure the thickness of your sponge from the point where it touches the surface of the instrument to the point where it touches your body.
If the sponge's thickness is ½”, select the size #3 Acoustifoam
If the sponge's thickness is greater than ½” add 1/16” to it's measurement and find the Acoustifoam size that comes closest to this sum.
When in doubt, feel free to contact us with questions!