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Bronze Member Username: OhiopilotPost Number: 14 Registered: Nov-04 | The case: 2003 BMW Z4 - crappy stock sound removed. Pioneer DEH-P8MP Head Unit w/XM and AUX modules. Front: 6.5"/4"/1" component set (JL Audio XR653 70W RMS 4ohm w/crossover) Rear: Only spaces for 6.5" and 4", used another XR653 set with 1" tweeter omitted. Front/Rear driven by a JL Audio 300/4 amp ***SUB*** JL Audio 10W3v2 Dual 4ohm Coils, 300W RMS (150 per coil), wired at 2ohm to a JL Audio 250/1 mono amp. ***BOX*** I have dimensions/plans for either sealed or ported box, as well as amp settings and all for either choice. (.625 cu ft sealed F3=43.8Hz, 1.125 cu ft ported, 33.7Hz) Sub is in the tiny trunk, only about 30" deep, 34" wide and 12.5" at lowest point toward the back (close fit for box). Both seats are practically directly against the wall between trunk and cockpit. ****QUESTION FOR DEBATE**** What is the best orientation for this sub? Face tailgate, face front bumper, face sideways? The best *space-wise* is facing rear or facing front. However, with the effort and $$$ spent on the system to this point, I'd prefer to get max'ed performance from the sub without overpowering the cockpit speakers. I look forward to your feedback and opinions here. |
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Bronze Member Username: OhiopilotPost Number: 15 Registered: Nov-04 | Second question set: This MDB material, that's just the medium-coarseness particle board sold at any Home Depot or Lowe's, right? If there is a specific grade or coarseness, please share. The picture I saw here http://www.bcae1.com/spboxnew2.htm looked pretty normal to me, as long as you get 3/4" thick. As for the insides of the box, do you fill it will any material? I know I've seen home audio subs loosely packed with material similar to chair stuffing. Do you always glue, or is nailing/screwing parts together okay? Finally, what do you caulk with, specifically? Just any old silicone sealant? Thanks in advance. Never built a box before, but seems easy enough. |
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Bronze Member Username: OhiopilotPost Number: 19 Registered: Nov-04 | bump... |
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Bronze Member Username: BusinessboyPost Number: 65 Registered: Sep-04 | just any decent 3/4 mdf will do. polyfil does the job - or any foamy type of material. yep i glue and use wood screws. - dont need to nail. yep i used a silicone sealant - anything to make it airtight. |
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Bronze Member Username: Mr_keboAlbertville, Al USA Post Number: 42 Registered: Nov-04 | Hey paddy! im trying to figure out how to get some dimensions to make a 1.2 cu ft box. Think you can help me out.the max lentgh it can be is 15 inches, the max depth is 9 inches and the max height is 21 inches |
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Bronze Member Username: OhiopilotPost Number: 20 Registered: Nov-04 | The link in my second post in this thread, http://www.bcae1.com/spboxnew2.htm , had a very easy to understand calculator for calculating box dimensions/volumes. And please, no thread hijacking...thx. |
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Bronze Member Username: WojoproPost Number: 12 Registered: Nov-04 | Polyfil is the cheapest... You can even buy it at radioshack! Woodscrews is way better than nails... Its alot tighter of a seal. You dont have to use the glue but it is a recommendation... Scratch that... Its a must! |
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Bronze Member Username: OhiopilotPost Number: 27 Registered: Nov-04 | Okay, construction question is sufficiently answered. NOW, how about the positioning question? ****QUESTION FOR DEBATE**** What is the best orientation for this sub? Face tailgate, face front bumper, face sideways? The best *space-wise* is facing rear or facing front. However, with the effort and $$$ spent on the system to this point, I'd prefer to get max'ed performance from the sub without overpowering the cockpit speakers. |
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Silver Member Username: Zacdavis~Post Number: 239 Registered: Sep-04 | hey ray, i have quite a bit of experience in spl, what kind of car do you have. the reason i ask is because many vehicles load and resonate differently. |
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Bronze Member Username: WojoproPost Number: 13 Registered: Nov-04 | I would have to say facing the tailgate in this car. |
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Silver Member Username: Zacdavis~Post Number: 242 Registered: Sep-04 | oops, i didnt even read his first post, duhh. i havent had any experience building boxes for that particular car. although i'd say goin with a sealed box might be best for you since space is an issue in your car. if you build the box "square" you can always try it with the subs up or back by simply flipping it, just an idea for ya |
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Coolthings Unregistered guest | This seems like the right place to ask this but I also hear things about tuning the box, can somone please explain this and how its done? |
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Bronze Member Username: OhiopilotPost Number: 28 Registered: Nov-04 | Zac, thx. I'm actually going to build both a sealed AND a ported box and try them both. You're probably right, sealed will be more versatile, and it all may be equal due to the small amount of trunk volume. My initial impulse was to face the sub forward, but then I realized how close it would be to the head/seat (just other side of the cockpit rear wall) and decided that probably would kill any sound from the rear channel mid-range speakers. Coolthings, tuning is a general term. For example, JL Audio subwoofers ship with factory recommendations as to exact dimensions of the box to build. Hell, it even varies the dimensions of the baffle wall based on the OHM rating of the same model speakers, it's that precise. In general, there are calculators out there, like the one listed above on that website, for calculating and building a box if your manufacturer only gives you performance values for the sub. In the end, though, remember the key phrase: everything is RELATIVE. Quality of materials, fit and finish are also factors in sound quality. Have fun, enjoy the project, and enjoy the sound that first time you power up your new toy, knowing that you may not be a sound engineer at Skywalker Ranch, but at least you built a box and a sound system that makes YOU happy and sounds good to YOU. In the end, that's all that matters, not some arbitrary Q rating. Finally, thank you to everyone who has given input on this thread. It was helpful to confirm my suspicions and I'm sure helped plenty of lurkers out there as well... |
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Bronze Member Username: OhiopilotPost Number: 29 Registered: Nov-04 | According to JL Audio, the recommended external dimensions for a box for their 10w3v2-D4 sub is as follows (presuming 3/4" material used): Sealed: 18" Wide, 11" High, 9" deep (Fc 54.8Hz, F3 45.8Hz, Qtc 0.97) Ported: 23" Wide, 12" High, 12.875" deep, port slot 1.25" wide, 10.5" High (Centered Vertically), 24.875" total slot length, Internal port extension wall 12" (Port Tuning 33.7Hz) |