I stopped at a yard sale while they were cleaning up for the day. Guy gave me an enclosure that was actually made to fit my exact truck and even has the matching tan carpet on it. Looks homemade, but solidly constructed.
I can figure out the volume, but the way it's made has me confused.
It is one shared volume cut for two 12s with a short 3" single port on top. I thought shared volume was a no-no, (other than isobaric) but I've only ever built two ported enclosures. Is this a viable design, or did the guy just do a hack job? How do two subs work sharing the same ported volume?
I can figure out the volume, but the way it's made has me confused.
It is one shared volume cut for two 12s with a short 3" single port on top. I thought shared volume was a no-no, (other than isobaric) but I've only ever built two ported enclosures. Is this a viable design, or did the guy just do a hack job? How do two subs work sharing the same ported volume?
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The subs would work together just fine if the signal was mono. That's the case for series or parallel monoblock powered systems for example. In terms of loading, it would function more or less like one moving mass, one system. But just split into two parts?
That's what my brain was thinking, but I've heard a few times before that it wasn't a good idea.
I'm tempted to cut it into two boxes and go with smaller, sealed enclosures. I certainly don't need the SPL (or massive size) of twin ported 12s in that tiny truck.
I'm tempted to cut it into two boxes and go with smaller, sealed enclosures. I certainly don't need the SPL (or massive size) of twin ported 12s in that tiny truck.
It's a bad idea to put a stereo system together in one shared volume on a boombox, for example. That would cause issues from phase to loading to resonances..
2 subs sharing the same space is fine as long as they are identical drivers and they both receive an identical signal. I can't attest to the single 3 inch port as that is dependent on the sub and it's recommended box size and port dimensions specified by the manufacture.
Ok. Good to know. I'll see if I can spec something to fit in there once I calculate volume. The port length is easy to change if it falls within something that a 3" hole can do efficiently.
Nice having hearing while it lasted. This is a case of a freebie that's going to cost me money 🙂
Nice having hearing while it lasted. This is a case of a freebie that's going to cost me money 🙂
So... assuming I find something with T/S parameters that work with half the volume of this box, buy two.... then cut the port length in half? Or double it?
You have to go with what the manufacture recommended port size which should be specified in size and length for that specific box dimension, or whatever box design program you use tells you for port dimensions.
Right, but I've never seen a manufacturer list recommendations for two drivers in double the volume. They would list a recommended volume and port for a single driver. So when I double it, do I cut the port in half or double it?
Either you have to double the port size, such as a 3 inch round port doubled is approximately 4.25 inches round according to square inch volume, or you have to add a 2nd port of the recommended size. The port length should remain the same for either single or twin ports.