JJ. Posted February 20, 2012 Report Share Posted February 20, 2012 (edited) Hi guys currently sorting out an enclosure for my new 18" lvl 4 DC's X2 now I want to do something a little different I am putting them in a box approx 14cuft less displacement of subs and want to put the port on top of the box scooped from back to front of box so port will be above the subs, I am assuming it is the same as doing a slot port inside the box except you obviously do not need to remove port displacement from the box?. Not sure on exact port dimensions yet but I want it to be windy so tuning to 27-29hz as last install of 4 x 15" lvl 4's was tuned to 33hz and want to try a bit lower this time again another reason for external port as it will be far easier to change. I am also assuming its just a case of cut a slot out of the top panel left to right with whatever width then just building the port onto that?. any pics or diagrams would be great and also advice. on a side note they are being powered by a SAZ-4500D clamped at 4936w @13v Thanks JJ Edited February 20, 2012 by JJ. Quote Alpine 9855r 2 x DC AUDIO LVL 4 18" 2 x Hybrid Audio Technologies L8 2 X Hybrid Audio Technologies L3 2 X Hybrid Audio Technologies L1 PRO 1 x SAZ 4500D 2 X SAX 50.4 AudioControl Matrix + AudioControl Epicentre 160 8 X hawker genesis deep cycle batteries Link to comment Share on other sites More sharing options...
Joe X Posted February 20, 2012 Report Share Posted February 20, 2012 The length of the external art of the port longer than the length of the port itself? Quote Link to comment Share on other sites More sharing options...
JJ. Posted February 20, 2012 Author Report Share Posted February 20, 2012 The length of the external art of the port longer than the length of the port itself? not sure what you are saying dude?. If this helps it's a scale model in google sketch up?. Obviously it will have plenty of flaring on the port top of port is 2" thick and sides will also have extra material added to round those over the same amount. Quote Alpine 9855r 2 x DC AUDIO LVL 4 18" 2 x Hybrid Audio Technologies L8 2 X Hybrid Audio Technologies L3 2 X Hybrid Audio Technologies L1 PRO 1 x SAZ 4500D 2 X SAX 50.4 AudioControl Matrix + AudioControl Epicentre 160 8 X hawker genesis deep cycle batteries Link to comment Share on other sites More sharing options...
Joe X Posted February 21, 2012 Report Share Posted February 21, 2012 Yes if the length of the port is 24 and is all external, the "length of external port" field cannot be above 24 (like 36). And ok if your drawing was made just fast but the holes of the subs cannot be that size. Quote Link to comment Share on other sites More sharing options...
412 CVX Posted February 21, 2012 Report Share Posted February 21, 2012 the port length includes the part that's external, you're just telling the program how much of the 24" port is external... the holes for the subs can't be that big. you have to account for the outer mounting ring which adds approximately .75" to the diameter of the sub (the actual number should be listed on DC's site) your output is going to suck if the box is tuned to 28 hz. you don't need to tune THAT low unless this is a home theater box. 30-35 hz should be good for daily and still drop lows it looks like there's 3 common port walls based on the sketchup model, but the port width needs to be 36.5" width. If you're running 4500 watts to these subs i sure as hell hope you've got good electrical and you tune the system right. i'm not even sure they can take a 4500 lastly, since you're running so much power to the subs, you at least need to double up on the baffle, and some bracing wouldn't hurt either. Quote Just say no to Ground Pounder Customs. My temp system build log More box buildssome cars do over 170db with one sub, so clearly my two 12"s can do that in my car, with my knowledge too! look out bitches! I'm with captain stupid. Link to comment Share on other sites More sharing options...
412 CVX Posted February 21, 2012 Report Share Posted February 21, 2012 (edited) dbl post... Edited February 21, 2012 by 412 CVX Quote Just say no to Ground Pounder Customs. My temp system build log More box buildssome cars do over 170db with one sub, so clearly my two 12"s can do that in my car, with my knowledge too! look out bitches! I'm with captain stupid. Link to comment Share on other sites More sharing options...
JJ. Posted February 21, 2012 Author Report Share Posted February 21, 2012 Whole box will be 2" thick and be braced the sketch up was just to show better than I could describe what I am thinking the port will be a drop on port again not part of the box. I checked DC and I do have room on the front for two subs again it's a quick sketch up I'm not that great with it tbh. 8 batteries and two alts so electrical is good. So the box should work ok and you guys reckon to tune a little higher 30-31??. Any other changes you can see need to be made?. Could some run through the Torres calc for me to show how it should look and where I have gone wrong? With a screen shot if poss first time using this program I usually use BBPro but my comp with that on is dead JJ (null) Quote Alpine 9855r 2 x DC AUDIO LVL 4 18" 2 x Hybrid Audio Technologies L8 2 X Hybrid Audio Technologies L3 2 X Hybrid Audio Technologies L1 PRO 1 x SAZ 4500D 2 X SAX 50.4 AudioControl Matrix + AudioControl Epicentre 160 8 X hawker genesis deep cycle batteries Link to comment Share on other sites More sharing options...
Skullz Posted February 21, 2012 Report Share Posted February 21, 2012 (edited) Your not accounting for the port being external with torres, in order to account for the port use the port as internal and find the net volume of the box and once you know that you'll have to add that to the actual gross volume and then subtract the sub and any displacements and enter that into the desired net volume in the lower right corner to get your actual tuned frequency. With everything you have shown and given dimension wise you'll be tuned to 24.5hz which is awfully damn low, i might be off a tad but that's as close to what you'll be tuned to as i could quickly figure out. Edited February 21, 2012 by Skullz Quote 01 Ford focus ZX3 Pioneer AVH-X491BHS PPI PC 4800.2 Morel Maximo 6.5" x2 Link to comment Share on other sites More sharing options...
412 CVX Posted February 21, 2012 Report Share Posted February 21, 2012 you didn't account for any bracing in the calc. fix the external port like suggested. also, there's not enough port area per cubic foot. shoot for 14-16 with those subs. Quote Just say no to Ground Pounder Customs. My temp system build log More box buildssome cars do over 170db with one sub, so clearly my two 12"s can do that in my car, with my knowledge too! look out bitches! I'm with captain stupid. Link to comment Share on other sites More sharing options...
JJ. Posted February 21, 2012 Author Report Share Posted February 21, 2012 Thanks guys will drop little one off at school and have another look at Torres calc, looks a great program just need to get my head around it. JJ (null) Quote Alpine 9855r 2 x DC AUDIO LVL 4 18" 2 x Hybrid Audio Technologies L8 2 X Hybrid Audio Technologies L3 2 X Hybrid Audio Technologies L1 PRO 1 x SAZ 4500D 2 X SAX 50.4 AudioControl Matrix + AudioControl Epicentre 160 8 X hawker genesis deep cycle batteries Link to comment Share on other sites More sharing options...
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