My box build plans... will this work?

ckunke002
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This is my first box i've ever tried to build. I just want somebody with experience to confirm that it will work for me, or that there's something I'm missing.

Box is for a Q 12".. wanted to give it 2.5 cubes tuned around 30-31 hz. This is what I came up with, does this look good/acceptable? Around 35 inches port length and about 14.5 square inches port area per each internal cube.

http://store.ficaraudio.com/q12/



 
Pretty big enclosure for a Q IMO. I run a 15 in 3.25 cubes for several years and it was a bottom end monster tuned at 32Hz...
Thanks for a response.. what would you suggest instead? I figured 2.5 would be about perfect, at the top end of the build range. And aside from the volume how does everything else look?

 
Okay, but it's simply a calculator lol.. and the math adds up. What's there that shouldn't be relied on here
Hey, I can't argue with you about the math adding up. I can do the math as well on paper to verify the re website. However that site does not take into account a lot of other parameters that the others do to give you the corrects specs for your sub. And what I mean is "specifically, your sub".
I don't make sub boxes, but I have made several in the past. I have bought from @BUCK and backed them up from re and they don't compare from the software he uses.

Also, re is always knocked on this forum for being inaccurate. Jus sayin.

 
Hey, I can't argue with you about the math adding up. I can do the math as well on paper to verify the re website. However that site does not take into account a lot of other parameters that the others do to give you the corrects specs for your sub. And what I mean is "specifically, your sub".
I don't make sub boxes, but I have made several in the past. I have bought from @BUCK and backed them up from re and they don't compare from the software he uses.

Also, re is always knocked on this forum for being inaccurate. Jus sayin.
I see. What would be a better alternative?

 
Man, first off, I wish you all the luck in the world getting your system where you want it. Secondly, I do not think you will get the sort of help you are looking for here. I too have been out to get a box built. I scoured the threads for information, and all I can find is people telling people that what they are out to do won't work. I have yet to see anything other than that, and just as your question sits unanswered as to what you could do, so do the many. You will get directed towards certain people to build for you, and I can only assume they do good work. I have contacted a few, and have not found any to be operating as a respectable business, but rather fly-by-night craftsmen. I am not knocking anyone in saying that, I myself operated in a similar way, and it provided the catalyst to become a legitimate operator in my chosen field.

If you are looking to build your box to the specifications given to you by a company that has millions to gain or lose, as well as their good name being put on the line, then build it. This is not rocket science. I only went looking to have a box built because I am far from my garage with the military right now. What I found was people telling me I would have to go to the home of the mountain king if I wanted a simple wood box made.BS. While it is true that there are many things that can effect the overall sound of your stereo, few things will be more detrimental to the sound quality than not building it because you were told not to. So, build your system to the best of your abilities, and enjoy it.

 
Man, first off, I wish you all the luck in the world getting your system where you want it. Secondly, I do not think you will get the sort of help you are looking for here. I too have been out to get a box built. I scoured the threads for information, and all I can find is people telling people that what they are out to do won't work. I have yet to see anything other than that, and just as your question sits unanswered as to what you could do, so do the many. You will get directed towards certain people to build for you, and I can only assume they do good work. I have contacted a few, and have not found any to be operating as a respectable business, but rather fly-by-night craftsmen. I am not knocking anyone in saying that, I myself operated in a similar way, and it provided the catalyst to become a legitimate operator in my chosen field. If you are looking to build your box to the specifications given to you by a company that has millions to gain or lose, as well as their good name being put on the line, then build it. This is not rocket science. I only went looking to have a box built because I am far from my garage with the military right now. What I found was people telling me I would have to go to the home of the mountain king if I wanted a simple wood box made.BS. While it is true that there are many things that can effect the overall sound of your stereo, few things will be more detrimental to the sound quality than not building it because you were told not to. So, build your system to the best of your abilities, and enjoy it.
Hahaha I really enjoyed that. Thanks for your advice! I will build it, but just trying to gather all the info I can to build the best one I can while I wait for it to arrive //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 
What about the particular sub makes you decide on that? I've never heard that much...
The xmax and piston area determine what size port you need for a given driver. With 28mm of xmax, the sub you have needs more port area than another 15" sub with 19 or even 11mm of xmax, as seen with a lot of entry level subs. Even though they're all 15s, they all have different abilities where moving air in and out of a vent are concerned and if you use too little port area, you wind up with poor performance and port noise.

And to clarify, xmax is the amount of distance the moving mass can be moved in one direction electrically. So a sub with 28mm of xmax can be moved by an amplifier 52mm peak to peak. That's about two inches and as you can imagine, that's moving a lot of air in one stroke.

 
The xmax and piston area determine what size port you need for a given driver. With 28mm of xmax, the sub you have needs more port area than another 15" sub with 19 or even 11mm of xmax, as seen with a lot of entry level subs. Even though they're all 15s, they all have different abilities where moving air in and out of a vent are concerned and if you use too little port area, you wind up with poor performance and port noise.
And to clarify, xmax is the amount of distance the moving mass can be moved in one direction electrically. So a sub with 28mm of xmax can be moved by an amplifier 52mm peak to peak. That's about two inches and as you can imagine, that's moving a lot of air in one stroke.
Interesting, thanks for the explanation. I knew that 28 xmax was quite a lot of excursion but didn't know I would need that much more port area.. so here i have it showing 2.5 by 14.5 inches... are you thinking something like 3" by 16? Couldn't there be potential downsides for going so big on port area?

 
Interesting, thanks for the explanation. I knew that 28 xmax was quite a lot of excursion but didn't know I would need that much more port area.. so here i have it showing 2.5 by 14.5 inches... are you thinking something like 3" by 16? Couldn't there be potential downsides for going so big on port area?
I'd go with something like 3-3.5 * 14.5 so that you don't increase the height of the box to accommodate the port. That will also increase the volume the vent consumes and the vent will need to be longer.

And yes, there are potential hazards to using too much port area but not "that much port area". That much port area is what that sub needs. If you were to put an entry level sub with 11mm of xmax in a box with that much port, you'd run the risk of mechanical failure due to over excursion of the sub. But that's not what you're doing. ;-)

Consequently, that's the primary reason prefab boxes get the bad rap they get.... 90% of them, and to be sure all the cheap ones, are made for low xmax subs. So, when people go out and buy a high xmax sub and stick it in a cheap prefab box, it sounds like shite and they blame the box builder for tuning it too high when in reality, it's probably tuned to a perfectly reasonable frequency (around 35Hz) and the real problem is that there isn't enough port area for the sub that's in it.

After all, there isn't much to wooden boxes and prefabs with the correct sub in them don't often fail and, they don't sound like shite most of the time.

 
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ckunke002

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