holes in the back of speaker cans

my friend and i are building some speaker cans. his dad told us we need to have a hole somewhere so the enclosure is not airtight and so the air behind the speakers has somewhere to go when the speakers are on. we were going to cut a hole and put gortex over it so no water gets in, but is it even necessary?

hey, this is the friend making the cans. i already drilled the holes for the gortex piece so the air can flow behind the speaker. whats more retarted, trying something new and putting the gortex over the holes (from the inside of the can) or putting putty over the four holes (each 1 inch in diameter) and pretending it never happened...

You do not need any holes in speaker cans for proper performance. You will get better performance with them sealed as air tight as possible. If your can is only 4" deep, you would need some holes or your sound would come out in a higher pitch as the woofer fights the small amount of air available for movement. If your can is at least 8" deep, seal it up. Possibly put a little poly fill in it to take out some of the reverb from the walls of the can. Look at all the speaker cans for sale, no holes Hope that helps...

You want it to be totally sealed. No holes.

Sorry

why no holes. is it because of protection of the speaker or sound reinforcement. And if its for sound reinforcement how would speaker cans differ from home audio and professional studio recording speakers which have holes in the back. If anything it seems there would be a greater need for holes because pvc is a more dense material than wood and carpet and so would not be able to absorb as much of the sound. thoughts?

Speakers with holes are called 'bass reflex'. The priciple is that a smaller speaker in a small enclosure will produce more (and deeper) sound if it is ported. Also intrinisic to this theory is low power. However if you are using larger speakers in larger enclosures with more power the port will actually hinder the reproduction of crisp sound. The moving part of a speaker is called the cone. It is moved back and forth (up to 10K times per second) by an electro magnet. In speakers with low power the magnet is unable to move the cone effectively in a sealed environment. In speakers with high power the magnet will move the cone too fast in an unsealed environment.

Therefore a good qaulity speaker with good power should be unported.

Hope that Dave the Science Guy explanation helps.

If you are going to "port" a speaker it needs to be specifically designed. Location, diameter and port tube length are all variables to consider.