jcarver

05-28-2012, 07:13 PM

So first this may be better to be moved to one of the discussion forums because its only theoretical talk as I don’t really have this problem. If so someone just say so and I’ll post it there. If not this may help clarify things for me and possibly others. Please try to read the full post before replying.

So I’ve been giving some thought to how box size, sound output, and power input all relate to each other and I’ve come up with some grey ideas of how it all connects but I’d like to get a clearer picture. Here are some of the things I’ve seen reference which may or may not be true.

Smaller box = higher power handling, or as some call it less efficient. In either case the why isn’t important only that it takes more power to reach full excursion of the sub.

Larger box = full excursion on less power

If the box is to big the sub gets sloppy and slow to return.

If the box is to small the internal pressure forces the sub back out too quickly.

Given those to be true (if they are), I was thinking about the manufactures recommended box sizes and how they come to those number. Obviously they use a mathematical equation that I’ve seen and don’t completely understand as well as real world testing but I’m wondering if those can be manipulated a little to work in our favor. Here’s what I’m thinking.

In this scenario let’s say we have a 12” speaker that is rated at 500w in a 2.5cuft box. Ideally you put 500w to it in this box and you reach its RMS potential. Now let’s say we up the box size to 3.0 or 3.5 etc, and its power handling goes down. Based on my understanding of how a subwoofer works you get sound output by moving the air. So in this bigger box let’s say we reach the full excursion at 400w due to the oversized box. It should be moving the same about of air right? Would this mean the sound output would be the same in terms of SPL on less power? If not why not? Sound quality aside on this by the way, I know the wrong box size can mess with how it sounds.

So I’ve been giving some thought to how box size, sound output, and power input all relate to each other and I’ve come up with some grey ideas of how it all connects but I’d like to get a clearer picture. Here are some of the things I’ve seen reference which may or may not be true.

Smaller box = higher power handling, or as some call it less efficient. In either case the why isn’t important only that it takes more power to reach full excursion of the sub.

Larger box = full excursion on less power

If the box is to big the sub gets sloppy and slow to return.

If the box is to small the internal pressure forces the sub back out too quickly.

Given those to be true (if they are), I was thinking about the manufactures recommended box sizes and how they come to those number. Obviously they use a mathematical equation that I’ve seen and don’t completely understand as well as real world testing but I’m wondering if those can be manipulated a little to work in our favor. Here’s what I’m thinking.

In this scenario let’s say we have a 12” speaker that is rated at 500w in a 2.5cuft box. Ideally you put 500w to it in this box and you reach its RMS potential. Now let’s say we up the box size to 3.0 or 3.5 etc, and its power handling goes down. Based on my understanding of how a subwoofer works you get sound output by moving the air. So in this bigger box let’s say we reach the full excursion at 400w due to the oversized box. It should be moving the same about of air right? Would this mean the sound output would be the same in terms of SPL on less power? If not why not? Sound quality aside on this by the way, I know the wrong box size can mess with how it sounds.