Hey, everybody!
Simple question (I think--but you know how that goes sometimes):
All things being equal between these two enclosures (same airspace, same port length, same construction, same vehicle, etc.), which one is preferable (ports in red)--(a) or (b)? They'll be facing the rear of a hatchback, in case that's relevant.
Or would you expect their sound/output to be identical? I imagine they would be identical, but I couldn't help but wonder if the two ports together in the center (b) might have turbulence or some other combined effect that they wouldn't have in (a). Or maybe they would theoretically, but it wouldn't be audible or otherwise detectable.
Hoping someone with more experience than I might weigh in. Thanks so much!
Simple question (I think--but you know how that goes sometimes):
All things being equal between these two enclosures (same airspace, same port length, same construction, same vehicle, etc.), which one is preferable (ports in red)--(a) or (b)? They'll be facing the rear of a hatchback, in case that's relevant.
Or would you expect their sound/output to be identical? I imagine they would be identical, but I couldn't help but wonder if the two ports together in the center (b) might have turbulence or some other combined effect that they wouldn't have in (a). Or maybe they would theoretically, but it wouldn't be audible or otherwise detectable.
Hoping someone with more experience than I might weigh in. Thanks so much!
Yes, i would think them the same. At the frequencies involved they are in much the same place.
What are you trying to build?
dave
What are you trying to build?
dave
Thanks for chiming in, Dave. Just looking to build (my first) standard, vented enclosure for two 12s. I've had these in a 4th order bandpass and, at the time (20 years ago!), they were the best thing I had ever heard! I'm a bit older now... looking for something simpler--but not as simple as a sealed enclosure (which I like--just going for some lower-end extension).
I've pretty much settled on this design and these dimensions--just didn't know whether there might be an advantage to (a) or (b). Thanks again!
If these are woofers, 2 ccabinet sare not really needed, and there is a huge advantage to mounting them push-push.
dave
dave
Yeah, they're 12-inch subs. The only reason they're partitioned separately is that I figured the center partition would provide some much-needed support on that plane. Can I ask what you mean by 'push-push' mounting? If you had said 'push-pull,' I would have assumed isobaric loading, but I'm not sure about 'push-push.' Thanks!
Push-pull does not imply isobarik.
Push-push ar eusing the 2 woofers pysically opposed, acoustically in phase. This gives active reaction force cancelation, removed some 90% (wild guess, maybe higher) of the box vibrational load.
Magnets together, drivers on opposite sides of the box.
The partition as brace breaks one of the fundemental general rules of bracing, you can do better.
dave
Push-push ar eusing the 2 woofers pysically opposed, acoustically in phase. This gives active reaction force cancelation, removed some 90% (wild guess, maybe higher) of the box vibrational load.
Magnets together, drivers on opposite sides of the box.
The partition as brace breaks one of the fundemental general rules of bracing, you can do better.
dave
Greets!
From dim memory without doing the math, 'b' will act as a single large vent WRT its end correction while 'a' will have two same-same ones, so a different tuning Vs 'b' for a given length.
'Sound' wise, the vent's HF BW, vehicle's acoustics will govern any differences.
From dim memory without doing the math, 'b' will act as a single large vent WRT its end correction while 'a' will have two same-same ones, so a different tuning Vs 'b' for a given length.
'Sound' wise, the vent's HF BW, vehicle's acoustics will govern any differences.
Hey, Dave... this took me down a rabbit hole, and I learned a lot on the journey. Thanks for expanding my horizon!Push-pull does not imply isobarik.
Push-push ar eusing the 2 woofers pysically opposed, acoustically in phase. This gives active reaction force cancelation, removed some 90% (wild guess, maybe higher) of the box vibrational load.
Magnets together, drivers on opposite sides of the box.
The partition as brace breaks one of the fundemental general rules of bracing, you can do better.
dave
A - With the ports on the outside works well with the drivers & ports vertically alligned, The ports then can help with thermal convection cooling. The drivers can be closer together, which can reduce beaming effects with higher frequencies, I have some mid tops configured like this.
B - Is a fairly common bass configuration where the drivers don't need to be closely coupled. By placing the port in the middle it can be a single wider port. The baffle has more inherent bracing as can be braced by the sides and the port walls. Probably works best horizontally when concidering cooling.
Both these configurations result in the same minimum front baffle area. Triangular corner ports can give a smaller frontal area - the increased depth then allows longer ports if necessary. Lots of parameters to concider!
B - Is a fairly common bass configuration where the drivers don't need to be closely coupled. By placing the port in the middle it can be a single wider port. The baffle has more inherent bracing as can be braced by the sides and the port walls. Probably works best horizontally when concidering cooling.
Both these configurations result in the same minimum front baffle area. Triangular corner ports can give a smaller frontal area - the increased depth then allows longer ports if necessary. Lots of parameters to concider!