Helmholz resonator and smoking soundports
A bottle can be tuned to a certain pitch by filling it partly with water. Hit it with a spood, or blow over the bottleneck and you will haer the pitch. The more water the lower the cavity volume and the higher the tone, the smaller the surface of the bottleneck the lower (yes lower) the tone.
A bottle can be tuned to a certain pitch by filling it partly with water. Hit it with a spood, or blow over the bottleneck and you will haer the pitch. The more water the lower the cavity volume and the higher the tone, the smaller the surface of the bottleneck the lower (yes lower) the tone.
The box of a guitar specially for the lowest bass tones can be regarded as a helmholz resonator with a cavity volume and a portsurface. Listen to an old Gibson Lloyd Loir L5 , a small body archtop with relative very small f holes. It produces an amazing deep base.
I have made this 18 inch archtop with 4 holes at the front and one hole at the rim. Maybe 4 times more hole surface compared to an old L5. It has an extreme powerful clear tone and doesnt have that boomy bass at all.
Made a picture from the inside of the guitar through the side hole. Notice the smoke comming through the hole reflected by the light.
