AJFrrranklin Posted May 4, 2016 Report Share Posted May 4, 2016 Do these box specs look good? Just a 18 yr old kid looking to learn more about car audio. Link to comment Share on other sites More sharing options...
AJFrrranklin Posted May 4, 2016 Author Report Share Posted May 4, 2016 Sorry about double post # when an engineer designs a box and gets a little carried away Just a 18 yr old kid looking to learn more about car audio. Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted May 4, 2016 Report Share Posted May 4, 2016 I can tell you put a lot of effort into that drawing and it looks very nice. As far as your design goes it looks like you have 3.35 cu ft net air space, is that correct? It also looks like you have two 3" ports for a pair of 12" subwoofers. You are most likely significantly undersized for port area. What subs are you using and what amp? "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
AJFrrranklin Posted May 4, 2016 Author Report Share Posted May 4, 2016 Thanks Triticum! Yes you are correct about the 3.35 cu ft. The two 3" ports are 9" long with the 1/2" flare at both ends. The subs are 12" Pioneer Champion Series PRO TS-W3003D4, they have an xmax of 13.8 mm or 1/2". I will either be running one or two Hifonics Brutus BRX1600.1D, don't know yet by I know that's what I will be running. Just a 18 yr old kid looking to learn more about car audio. Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted May 4, 2016 Report Share Posted May 4, 2016 OK, so for reasons I will never understand, Pioneer recommends a single 3" port for those subs, this is EXTREMELY undersized. I guess they probably recommend that so people will think their sbus will fit in smaller spaces. To get good performance you need to keep port velocity low. Under 22 m/sec is best, anything much above 30 m/sec and port compression will destroy your output. With two 3" ports you have just over 14 sq in of port area. On 1600 watts (a single BRX1600.1D) your port velocity is going to be like 90 m/sec, you will basically have a leaky sealed box. For best performance I'd recommend 25 sq in of port area per sub, or about three times what you have now. This is going to make things tough to fit, since as ports increase in area they need to increase in length to keep tuning the same. You could probably get away with 20 sq in per sub, but 25 would be better. Also, since those are 2 ohm DVC subs, with a pair you can wire them to 1 ohm final load, which will work well with a BRX1600.1D. I wouldn't run any more power than that though or you will probably let the magic smoke out of those subs. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
AJFrrranklin Posted May 4, 2016 Author Report Share Posted May 4, 2016 MI got the port size from psp precision aero ports. I don't understand why this wouldn't work? How do you calculate the port speed? Sorry I just need more explanation. I like learning as much as I can, like in my signature Just a 18 yr old kid looking to learn more about car audio. Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted May 4, 2016 Report Share Posted May 4, 2016 No worries man, everyone has to learn somehow. So to determine port velocity you have to use box simulation software. There are a lot of choices out there. WinISD works well and is free. If you don't want to use simulation software a ROUGH guideline is 15 sq in of port are per cubic foot of net volume. I don't like that guideline because its not always the right thing to do, simulation software gives a MUCH better answer, but its better than just using a 3" port and in your case it works out about right. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
AJFrrranklin Posted May 4, 2016 Author Report Share Posted May 4, 2016 Okay well I will try and design a new box by tomorrow then repost and see if it works out well. Thanks Triticum! Just a 18 yr old kid looking to learn more about car audio. Link to comment Share on other sites More sharing options...
AJFrrranklin Posted May 10, 2016 Author Report Share Posted May 10, 2016 Okay so new box design has a retangular port. 15" by 2" by 16.5 inches long. Does is sound correct? The total box dimensions and design are as shown. Just a 18 yr old kid looking to learn more about car audio. Link to comment Share on other sites More sharing options...
AJFrrranklin Posted May 10, 2016 Author Report Share Posted May 10, 2016 Just a 18 yr old kid looking to learn more about car audio. Link to comment Share on other sites More sharing options...
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