Can i take a 12 in subwoofer and cut a new hole in a 10 subwoofer box and it still work and sound right

Solution
Not likely. The box dimensions and port size are specific to not only the size of the subwoofer, but also the specific subwoofer. Two different 12" subwoofers may have entirely different enclosure specifications, and almost always do.

Will it WORK? Probably. Will it sound RIGHT? Maybe, but it's unlikely. If the enclosure is smaller, the base will be extremely tight, there will likely be port noise since the port will not have been designed for that subwoofers characteristics and if the enclosure is too small, and the port too restrictive, you will likely overheat the voice coil and damage the subwoofer if you drive it at normal power tuned to the wrong frequency.
Not likely. The box dimensions and port size are specific to not only the size of the subwoofer, but also the specific subwoofer. Two different 12" subwoofers may have entirely different enclosure specifications, and almost always do.

Will it WORK? Probably. Will it sound RIGHT? Maybe, but it's unlikely. If the enclosure is smaller, the base will be extremely tight, there will likely be port noise since the port will not have been designed for that subwoofers characteristics and if the enclosure is too small, and the port too restrictive, you will likely overheat the voice coil and damage the subwoofer if you drive it at normal power tuned to the wrong frequency.
 
Solution

ien2222

Distinguished
Actually, having the box small won't cause any more overheating than a larger one.

As for actually doing it, it'll sound fine...insomuch as it won't sound odd. However, it is extremely doubtful that you'll be making full use of any potential bass extension/total output that the 12 might have over the 10.
 
Your opinion is noted, however, since I've been designing custom boxes and used to work with several competition level shops doing custom fabs, I'm telling you flat out that you are wrong.

This goes for all speakers not just subs. Ideally the volume of the box creates a dampening effect on the movement of the speaker. If the volume is too small, it will dampen it too much, especially if it is a sealed enclosure. This will cause loss of frequency and introduce distortion. Distortion creates heat and heat sure as ********* hell WILL damage your voice coils and possibly the driver as well.

It will also reduce how fast the speaker can move - this also has many effects on performance including the potential for clipping. Note that if the walls of the enclosure flex - are not rigid - this compromises performance as well as the volume changes dynamically. All speakers benefit from having the proper type and size of enclosure and when an enclosure is significantly too small or too big, or the ports are not the right size, length and diameter, there will definitely AT MINIMUM be distortions or sound issues like lack of volume or muddy sound and at worst may, and in many cases does, damage the speaker in a relatively short amount of time.

It also takes more power to achieve the same amount of volume if the enclosure is too small. The small size of the box makes it harder for the speaker to move. As the speaker moves, the pressure difference inside the box is increased due to the small size of the box. If you are running a small amp, the reduced box size will cause additional strain on the amplifiers as well. Finally, if the speaker is not a high quality one with a very stiff cone, the small box will cause additional distortion due to increased cone distortion from the higher pressures. In summary, the system becomes much less efficient and potentially damaging to both the speaker and the amplifier.

And if the box is ported, and the volume is not accurate for the specific speaker as per the manufacturers suggested dimensions, it will definitely sound like crap.
 

USAFRet

Illustrious
Moderator


Unlikely it will actually sound "correct".

The box is built to a particular speaker. It would be better for you to delve into speaker design, and build your own box for that 12" driver.
Rather than hacking up the 10" box, and ending up with junk sound.
 
I guess I should have asked in the first place if this is a home stereo subwoofer or a car audio system? And as well, what the impedance of the subwoofer is. If you can find the model of the subwoofer, the manufacturers page usually will provide a recommended specification for the enclosure size for both ported and sealed enclosures. You can then use a box calculator to help determine if you are even within reasonably close tolerances and what frequency, based on port size or lack of ports, that the enclosure will end up being tuned to and then compare that to the recommended tuning point for that specific speaker.

If this is just for fun and sound quality is unimportant, then so long as you land within about 8-10db one way or another you will likely not be at risk of any serious damage although much also depends on how much power you are supplying to the sub and what the impedance of your amp is as well.

As USAFRet said, it would be a lot better if you simply built a box FOR that speaker. The result would likely be a lot better and the materials are probably in the 30-35 dollar range if you build it correctly using 3/4" MDF material. You don't even need to build a fancy port into it. A 3" or 4" round PVC port will work fine so long as it is tuned to the correct frequency or is at least within a fairly close range.