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I NEED HELP I HAVE COMPETED IN IN NSPL I AM NOW PUTING TOGETHER A NEW SYSTEM IM CHANGING FROM TSW303C 12'S TOO TSW383CDVC 15'S POSSIBLY BUT THEIR VAS IS 21. SOMTHING CUBIC FEET MY CAR IS A 92 FORD 4 DOOR TEMPO ROUGHLY FROM FRONT SEATS TO DAS WINDO TO DAS TO SEATS AND FRONT FLOOR BOARD I HAVE GIVE OR TAKE 33 CUBIC FEET IM WANT TO RUN 6 15'S PORTED OR SEALD I HAVENT DECIDED BUT I NEED TO KNOW HOW WILL THE VAS AFFECT MY SPL AND HOW CAN I COMPENSATEWIIL THE LACK OF AIR SPACE MAKE MY FREQ HIGHER LOWER ETC ALSO DEPENDING ON BOX SIZE I CAN AD A FEW CUBIC FACE ALSO DOES THE REAR OF THE CAR AIR SPACE COUNT CONSIDERING IT WILL BE SEALD OF FROM THE FRONT
Posts: 375 | From: Fayetteville Nc | Registered: Jan 2000
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I NEED TO KNOW HOW THE VAS OF THE PIONEER 15S WILL AFFECT MY SPL AND HOW TO COMPENSATE IF POSSIBLE
Posts: 375 | From: Fayetteville Nc | Registered: Jan 2000
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Bobe: Vas is only one of the factor from speaker. In order to calculate proper box size, you must know at least also Fs Qts. Vas can tell you something, but not much.
15 inch speakers usually move more air, than 12 inch. This is not exact number but you need approximately 2 12" to equal one 15".
Ported boxes are more efficient than closed, and smaller boxes play higher than big ones.
Vas is not affecting SPL directly. It only affect box size. Usually bigger Vas mean bigger box. But efficiency of 15" is usually higher than 12".
Posts: 1820 | From: Ljubljana, Slovenia | Registered: Jan 2000
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HEY DR THANKS BUT I KNOW ABOUT THE BOX AIRSPACE FROM WHAT I SOME WHAT KNOW ABOUT VAS IS THATIT IS THE CALCULATED SPACE THE WOOFER FILLS UP NEEDS TO OPERATEFULLY SOMETHING LIKE THAT CORRECT ?SO I HAVE ROUGHLY 33 CUBIC FEET IN THE CABIN (FRONT OF THE CAR) THE VAS OF ONE TSW383DVC IS 21 SOMETHING CUBIC FT X 6WOOFERS IS A LOT OF VOLUMETO BE NEEDED SO SINCE I ONLY HAVE 33 CUB FT HOW WILL THAT AFFECT MY SOUND AND OR INCAR FEQUENCY RESPONSE THANKS Posts: 375 | From: Fayetteville Nc | Registered: Jan 2000
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Vas means: equivalent air volume, or the air volume having the same acoustic compliance as the speaker suspension. It is only factor about suspension. Not recommended box size!
Cabin is not sealed 100% so it don't act like speaker box. So cabin volume is not factor when calculating box (unless extreme SPL).
The more important is what kind of box you will have behind the woofer. Even if Vas is 21 cuFt, box can (must) be much smaller. It all depends what results you want to hear at the end.
In order to calculate proper box size you must also know Fs and Qts, if you want to perform basic calculations. If you have that I can help you, and if you find somewhere Vas, there should also be some other data.
Posts: 1820 | From: Ljubljana, Slovenia | Registered: Jan 2000
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OK DR I MUST BE CONFUSING YOU SOME WHERE I HAVE MY BOX PLANNED ALREADY WITH MY SPEAKER SPEC SHEET AND PROGRAMED WITH MY BLAU BOX PROGRAM SO I GOT ALL THE SPECS ON THE SPEAKER AND TWO PLANS FOR THE BOX I JUST HAVE TO MAKE UP MY MIND OF SEALED OR PORTED OK AND I PLAN ON COMPETEING IN SPL SO IN WHAT YOURE TELLING ME IS MY 6 I5S VAS WILL NOT AFFECT MY MEASURED IN CAR SPL READING? CONSIDERING I ONLY HAVE 33 OR SO CUBIC FEET IN MY CABIN AREA ? HEY IM SORRY IF IM FRUSTRATING YOU DUDE BUT I APPRICIATE THE HELP ITS JUST I THINK YOU WONT UNDER STANDING MY ? THANKS
Posts: 375 | From: Fayetteville Nc | Registered: Jan 2000
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I understand what you want to ask. I think, that your big Vas has nothing to do with cabin volume. Vas is only theoretical factor. It equivalent of air compared to speaker suspension in free air. When you build a box speaker is keept in place with suspension and amount of air in the box.
Unless you will have extreme SPL car, with totally sealed interior, volume of cabin don't play almost any role in speaker suspension.
Ported boxes can be 3 dB louder! So I suggest you to go with that. But be sure to have ports big enough. Bigger ports usually produce more SPL, but drawback is, that they must be longer than smaller ones. Be sure, that you have enough place between ports and back wall!
If you can, buy some sort of SPL meter. This way you can check some results before competition. Even cheapest one can be good investment. The only thing is, that with cheap ones you can only basically set system at lower levels, and clear biggest mistakes in determine: port lengths, resonant frequency, speaker placement, gain settings etc.
You are not frustrating me, I am writing answers for fun, because at the moment I have nothing better to do. And if you want, I can tell you more haw to set SPL car.
Posts: 1820 | From: Ljubljana, Slovenia | Registered: Jan 2000
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YEAH IM THE ONE IVE ALREADY TALKED TO ALLAN HE TOLD ME AND I MIGHT BYE BACK MY 400 AND HIS NEW 400S BUT IF YOU REMEMBER MY 8 PIONEER 12S THEN YOU KNOW IM A PIONEER FREAK I KNOW THEY ARENT THE BEST FOR COMP BUT THE HVNT LET ME DOWN YETEVERY NSPL SHOW IVE GONE TO AND OR CAR SHOW IVE PLACED AND IVE BEEN TALKING TO ALL IN FACT IVE BEEN TRYING TO GET HIMTO GET ON HERE THANKS GUYS OH WHO IS THIS
Posts: 375 | From: Fayetteville Nc | Registered: Jan 2000
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OH YEAH ACCORDING TO MY BOX PROGRAMI CAN REACH 100 DB BETWEEN 53 TO 65 HZ DEPENDING ON MY BOX SPECVB AND TUNING COMPARED TO 92 TO 94 DB IN SEALED BUT I LOVED MY SEALD PLUS IN A FLAT WALL ITS KINDA TRICKY TO ADD PORTS SO IVE GOT TO GET IN THERE AND DO SOME GOOD MEASURING OH NO PROB ABOUT PORTS IVE GOT SOME4 INC PVC LEFT OVER FROM A NOTHER PROJECT AND OR I MIGHT HAVE TO SLOT IT DEPENDING ON MY ROOM THANKS
Posts: 375 | From: Fayetteville Nc | Registered: Jan 2000
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HEY DOC ANY IDEA WHERE I CAN MAY BE GET A CHEAP GOLDLINE HAND HELD OR SOMTHING I KNOW OF KRISS AUDIO THAT HAS ONE THAT PLUGS INTO A MULTI METER BUT THATS STILL KINDA STEEP ALSO MY CABIN ISNT COMPLETELY SEALD BUT ITS PRETTY TIGHT BUT IM NOT GOING EXTREME IM TRYING TO STAY IN SEMI MODIFIED MINE WILL BE A DAILY DRIVER FOR A WHILEHEY CHECK OUT MY NEW POSTIN SPL I BELIEVE AND TELL ME WHAT YOU THINK THANKS
------------------ WHAT IM LUCKY ENOUGH TO HAVE N.C. PLATES U.S. AMPS UH OH STARTIN OUT LITTLE BUT HEY ALL THE LITTLE GUYS WATCH OUT FOR ME IM PIONEERING IN THE ART OF SPL IVE GOT JUICE
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i used to have the red scoupe that sat on the ground....15"tristars....4-15"wall....used to be in lowered atmosphere, but now i got a 4wd. been here about three years now. as a matter of fact, we were coming back from the olive garden tonite and i saw you up at the light at skibo and mcphearson church.....
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hey thats kool i had asked alan about you cus i didnt remember you we were do ing some plannig about what im going to do we were checking my blaubox to his term 1 yeah i went to wal mart for supplies(staple gun new jigsaw ) alright man maybe ill see you around later
------------------ WHAT IM LUCKY ENOUGH TO HAVE N.C. PLATES U.S. AMPS UH OH STARTIN OUT LITTLE BUT HEY ALL THE LITTLE GUYS WATCH OUT FOR ME IM PIONEERING IN THE ART OF SPL IVE GOT JUICE
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OK bobby, I think we have come to the conclusion in that Vas is not a ffactor in your car...do not worry about it any more. I think you know Scoupen..if ya saw him you would recognize him. Anyways..do the 6 15's in the ported box..not 8. Trust me on this one.
Posts: 9032 | From: Linden, NC | Registered: Jan 2000
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