On the right is a photo showing the unobtrusive modification.
Below are 6 short soundclips made before and after the port is fitted, in mp3 format (mono).
The frequencies of the notes being recorded range from 80Hz down to 60Hz.The recordings were made using a Sony ESM-MS907 microphone, which has a level frequency response down to 100Hz, below which it goes a little thin. The improvement in sound is at least as good as we've recorded.
The recordings were made in a room 13 feet (4 metres) square - small rooms such curtail extended bass response.
The recordings are based on the following notes, which are notated in contra notation (sounding one octave below classical guitar and 2 octaves below pitch)
|E||C||Descending scale played on string 5|
Note - you won't hear any difference if you listen on a laptop or a PC with a small speaker - you need good speakers to hear the deep bass!
The contrabass with the port fitted