HDC3 Box build help

[GhostMemphis 10+ year member]

O.k. so after changing all the wiring and alternator and batteries my two 12" HDC3's (copper) are still not hitting loud or low enough for me. So I am thinking it has to be that my box is to small (just over 4cubic feet 35W x 16H x 16D external measurements). I talked to mike and he gave me dimensions to make a box that is around 5.5 cubic feet, but I have a question about whether it is better to have them in a shared chamber or separate chambers. Which would you suggest and why?

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[jake760 10+ year member]

Thats only about 4 cubic feet gross, way too small for those subs after you figure in sub and port displacement. I would put them in about 4.5 cubic feet net after all displacements, common chamber.

 

[GhostMemphis 10+ year member]

Mike gave me the dimensions to get 5.5 cubic ft before and 4.517 after displacements (29W x 17H x 20D internal) in a common chamber. I just have to find a good box builder in the Maryland area (or and online builder who can ship it to me) to get it built and tuned to spec.

MY biggest question was basically is there any audible difference between common chambers or separate chambers.

 

[RAM_Designs 5,000+ posts]

MY biggest question was basically is there any audible difference between common chambers or separate chambers.

Single chamber boxes take up less space because of a couple things.

1) You're able to use a little less air space per sub when sharing a common chamber.

2) You don't have to use two ports which would each need to be a little longer than a single larger port containing the same port area.

I always use a common chamber myself, just saves that little extra space. Also, if the box you're about to build is only 1ft^3 different going from gross to net volume, then I'd imagine the port is either too small or tuned too high. But people do swear by tuning the HDC's higher than normal(although I've seen a lot of people complain about a lack of low-end).

Do you know what the box is tuned to, and how big is the port?

 

[pro-rabbit 5,000+ posts]

Mike is right. Im ah..."used" to the Audioque product if you will //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif 4.5 if about right. He likes to tune a bit higher then I do though.

 

[GhostMemphis 10+ year member]

This is what mike sent me to go off of to have the box built.

I would do 28(w)x17(tall)x20(deep) this will give you 5.509 cubic ft, then you multiply it by .82 to get volume after displacements... 4.517 perfect for the sub, then total x 16sq" to get port area, so 72.28 is the port area and then divide by the height of the box, 72.28/15.5= 4.663 is how wide the port opening needs to be and the length of the port needs to be 18" long... This will give your your internal dimensions including all displacements, and will tune the box at the 35hz.

Edit* He later sent me an email and told me to make it 29 inches wide.

 

[pro-rabbit 5,000+ posts]

Lol, call mike and ask him for my number //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif lol

 

[GhostMemphis 10+ year member]

PM sent rabbit

 

[RAM_Designs 5,000+ posts]

This is what mike sent me to go off of to have the box built.
I would do 28(w)x17(tall)x20(deep) this will give you 5.509 cubic ft, then you multiply it by .82 to get volume after displacements... 4.517 perfect for the sub, then total x 16sq" to get port area, so 72.28 is the port area and then divide by the height of the box, 72.28/15.5= 4.663 is how wide the port opening needs to be and the length of the port needs to be 18" long... This will give your your internal dimensions including all displacements, and will tune the box at the 35hz.

Edit* He later sent me an email and told me to make it 29 inches wide.

That's not tuned to 35hz, it's actually in the 39-40hz area.

 

[GhostMemphis 10+ year member]

wow I am glad I posted here. I want it tuned as low as I can get it to give me slamming lows, but also nice output on the high bass notes.

 

[pro-rabbit 5,000+ posts]

We will get it worked out for you.

 

[GhostMemphis 10+ year member]

I trust that you will. You guys seem a lot more knowledgeable than me or anyone I know. Plus I am pretty skeptical of the audio shops near me. They are only about a quick buck. They out right lie to you about anything to make money. Case in point before I learned about the difference in wires I was sold 25 feet of Q-power 1/0 gauge for 9 bucks a foot, and they claimed this was the best wire that money could buy...

 

[armyatc 10+ year member]

I trust that you will. You guys seem a lot more knowledgeable than me or anyone I know. Plus I am pretty skeptical of the audio shops near me. They are only about a quick buck. They out right lie to you about anything to make money. Case in point before I learned about the difference in wires I was sold 25 feet of Q-power 1/0 gauge for 9 bucks a foot, and they claimed this was the best wire that money could buy...

WOW. if you are ever looking for great wiring etc. google KNUKONCEPTZ

 

[GhostMemphis 10+ year member]

WOW. if you are ever looking for great wiring etc. google KNUKONCEPTZ

Yea I have learned about them and actually bought a fee things from them lately. I went with the shok comp power wire tho. and 2/0 welding wire for the big 3 this time. That situation was about a year and a half ago, but lets just say thanks to me being military and them ripping me off my commander worked on getting their store put into or post papers.

P.S. armyatc if you are still in afghan good luck. I know how it is out there (I just returned from my 4th tour out there.)