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View Full Version : My box build plans... will this work?



ckunke002
11-29-2013, 01:06 PM
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/

http://i223.photobucket.com/albums/dd215/ckunke002/ScreenShot2013-11-28at101643AM_zpsf388e256.png (http://s223.photobucket.com/user/ckunke002/media/ScreenShot2013-11-28at101643AM_zpsf388e256.png.html)

mlstrass
11-30-2013, 02:46 AM
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...

Staynlean
11-30-2013, 02:50 AM
Why you using re? It's not reliable.

ckunke002
11-30-2013, 03:30 AM
Why you using re? It's not reliable.

Okay, but it's simply a calculator lol.. and the math adds up. What's there that shouldn't be relied on here

ckunke002
11-30-2013, 03:32 AM
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?

Staynlean
11-30-2013, 03:40 AM
Okay, but it's simply a calculator lol.. and the math adds up. What's there that shouldn't be relied on hereHey, 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.

ckunke002
11-30-2013, 04:07 AM
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?

SamIam71
11-30-2013, 09:11 AM
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.

bbeljefe
11-30-2013, 10:12 AM
That looks like it will be okay but I would recommend closer to 20inē of port area per cube with that sub.

ckunke002
11-30-2013, 09:11 PM
That looks like it will be okay but I would recommend closer to 20inē of port area per cube with that sub.

What about the particular sub makes you decide on that? I've never heard that much...

ckunke002
11-30-2013, 09:16 PM
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 :D

SamIam71
11-30-2013, 09:44 PM
I am doing the same. Going to pick up MDF tomorrow. Have two Sundown SA8v2's and an alpine MRX-110 in the mail. Good luck man.

bbeljefe
11-30-2013, 10:09 PM
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.

ckunke002
11-30-2013, 11:05 PM
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?

bbeljefe
12-01-2013, 12:06 AM
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.

mlstrass
12-01-2013, 01:42 AM
That looks like it will be okay but I would recommend closer to 20inē of port area per cube with that sub.

Why would you suggest that? I've done several boxes for Q's and BTL's and 12-14^2 has been more then enough. Q has a rather loose suspension, so I wouldn't do that much port area....

---------- Post added at 12:42 AM ---------- Previous post was at 12:41 AM ----------

OP how much power do you have and what music do you mostly listen to?

bbeljefe
12-01-2013, 02:05 AM
Why would you suggest that? I've done several boxes for Q's and BTL's and 12-14^2 has been more then enough. Q has a rather loose suspension, so I wouldn't do that much port area....

---------- Post added at 12:42 AM ---------- Previous post was at 12:41 AM ----------

OP how much power do you have and what music do you mostly listen to?

Is this (http://store.ficaraudio.com/q12/) not the sub in question?

From the looks of the TS numbers, that's not a high compliance sub. Also, what is your benchmark for the claim; "more than enough"? Did you calculate port area before building? If so, what method/software did you use?

Did you build with less and more port area and then test the enclosures in controlled environments? If so, what were the results?

jeffdachef
12-01-2013, 02:27 AM
I see. What would be a better alternative?

winISD, its not the best of the best but its the best FREE downloadable box building software, lets you put the TS parameters of the sub in there and also shows you what the frequency response of the enclosure for the sub will be like in a graph. theres tutorials on youtube on how to use it.

ckunke002
12-01-2013, 04:00 AM
Why would you suggest that? I've done several boxes for Q's and BTL's and 12-14^2 has been more then enough. Q has a rather loose suspension, so I wouldn't do that much port area....

---------- Post added at 12:42 AM ---------- Previous post was at 12:41 AM ----------

OP how much power do you have and what music do you mostly listen to?

It's also worth noting I did not add on the additional spider option. I listen to a lot of hip-hop, but not much of the modern stuff that bassheads listen to when showing their cars. So that's to say not quite so much emphasis on 30-40hz boosted synth basses. I listen to a lot of jazz and alt/prog/indie rock and metal too, a lot of stuff with drum and bass grooves. I'm tuning to around 30/31 so I obviously don't want a big spike and do want it to dig low and be pretty balanced.

And i've done big 3 and have an HC1400 under the hood but that's it. I was planning on giving the sub about 900/1k at full tilt

ckunke002
12-02-2013, 12:12 PM
Bump?

mlstrass
12-03-2013, 02:52 AM
As long as you have some EQ to tame down the bottom end you should be happy....

ckunke002
12-03-2013, 05:23 AM
As long as you have some EQ to tame down the bottom end you should be happy....

So what would you suggest for internal cubes?

mlstrass
12-04-2013, 11:36 AM
3.25 - 3.75 net is what I'd do. with 12^2 port per net cube

ckunke002
12-04-2013, 11:40 AM
surely you're thinking of a 15 haha.. i have a 12.. so for 2.5 internal around 30 sq inches port? Does it matter how big width and height are just as long as it gets to that number?