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#1
Posted to rec.audio.car
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sub woofer box problems, need info
we currently tried making a band pass box to put into back of a jeep
wrangler, with the back seat still in the vehicle, however it dosent function as well as i had hoped. the boxes sound is weak, and we dont know what it is due to. we are running 2 type e alpines, 750 watts each and a 1200watt ultimate amp. the box itself has to be the problem, beacuse the amps were being used in another box sucessfuly, with subs. the cubic feet is meant for two 10ns, so we have adaquate space. we need your input on what we should do to improve performance, and or make the sound more powerfull. thanks for all future imput. |
#2
Posted to rec.audio.car
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sub woofer box problems, need info
what are the specs on the box you built? -- KU40 |
#3
Posted to rec.audio.car
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sub woofer box problems, need info
ruens wrote:
On Wed, 13 Jun 2007 17:40:47 -0700, minuteman wrote: we currently tried making a band pass box to put into back of a jeep wrangler, with the back seat still in the vehicle, however it dosent function as well as i had hoped. the boxes sound is weak, and we dont know what it is due to. we are running 2 type e alpines, 750 watts each and a 1200watt ultimate amp. the box itself has to be the problem, beacuse the amps were being used in another box sucessfuly, with subs. the cubic feet is meant for two 10ns, so we have adaquate space. we need your input on what we should do to improve performance, and or make the sound more powerfull. thanks for all future imput. A little more info would be helpful such as available space you have to work with, and speaker size. More to the point: what exact models of speakers, their T/S parameters, and how you've got them wired, would help. Also be useful to know how the box is designed, and what it's constructed of - 1/2" plywood 1" MDF. |
#4
Posted to rec.audio.car
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sub woofer box problems, need info
In article . com, minuteman wrote:
we currently tried making a band pass box to put into back of a jeep wrangler, with the back seat still in the vehicle, however it dosent function as well as i had hoped. the boxes sound is weak, and we dont know what it is due to. we are running 2 type e alpines, 750 watts each and a 1200watt ultimate amp. the box itself has to be the problem, beacuse the amps were being used in another box sucessfuly, with subs. the cubic feet is meant for two 10ns, so we have adaquate space. we need your input on what we should do to improve performance, and or make the sound more powerfull. thanks for all future imput. When I make a BP box, I use the calculations to predict SPL and filtering. The only way to verify the box is run a sweep test outside the vehicle, best outside in the yard. By comparing actual to predicted, this will tell if it working as it was predicted. greg |
#5
Posted to rec.audio.car
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sub woofer box problems, need info
You have to use software or factory specs to make a bandpass box. I did one before I could get it a long time ago and it worked nice, it was tuned low and I hooked a small house stereo to my PC with some nice bookshelf speakers....it sounded great, could play CD off the PC, and could play radio too. It went loud for PC speakers and thumped. It was about 30 or 35W/ch stereo. All that you did was hooked it up parallel with no crossover, that is why I made one with a DVC 10". Anyway, later I ran out of room and made a smaller 8" one because the 10" made more than enough bass. It didn't work! I moved my stuff later and bought a small speaker set with sub for the PC. Ran the 10 in a car briefly but it didn't go loud enough for that and was tuned too low. One day I plugged both into winISD and the 10" was right on for what I wanted, but the 8"....it was all wrong. Turned out it was an IB speaker and had a nasty response curve; it only hit in two different Hz and nothing between. Even changing the box would not fix it. Also the box and port has to be real close to right or it screws it up. I did use the 10 box with a bought 10 BP (both single driver) and it worked real nice, mine was low and that one was higher. Problem was it filled my whole trunk. -- s3sqguy |
#6
Posted to rec.audio.car
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sub woofer box problems, need info
In article , s3sqguy wrote:
You have to use software or factory specs to make a bandpass box. I did one before I could get it a long time ago and it worked nice, it was tuned low and I hooked a small house stereo to my PC with some nice bookshelf speakers....it sounded great, could play CD off the PC, and could play radio too. It went loud for PC speakers and thumped. It was about 30 or 35W/ch stereo. All that you did was hooked it up parallel with no crossover, that is why I made one with a DVC 10". Anyway, later I ran out of room and made a smaller 8" one because the 10" made more than enough bass. It didn't work! I moved my stuff later and bought a small speaker set with sub for the PC. Ran the 10 in a car briefly but it didn't go loud enough for that and was tuned too low. One day I plugged both into winISD and the 10" was right on for what I wanted, but the 8"....it was all wrong. Turned out it was an IB speaker and had a nasty response curve; it only hit in two different Hz and nothing between. Even changing the box would not fix it. Also the box and port has to be real close to right or it screws it up. I did use the 10 box with a bought 10 BP (both single driver) and it worked real nice, mine was low and that one was higher. Problem was it filled my whole trunk. I think you need software, and driver specs. Actually you don't need software, as I did before software was available, use longhand. By using bandpass, you can modify elements to make it fit in your application, such as Q, S, SPL, and bandwith. Sometimes it will not work since there are limitations on those and the driver. grge |
#7
Posted to rec.audio.car
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sub woofer box problems, need info
On Jun 19, 10:08 am, s3sqguy s3sqguy.2sf...@no-
mx.forum.carstereos.org wrote: Turned out it was an IB speaker and had a nasty response curve; it only hit in two different Hz and nothing between. Even changing the box would not fix it. Yep, not all drivers are suitable for bandpass enclosures. On a somewhat related note, here's how modifying the various components of a single-reflex bandpass enclosure will alter you response curve (this is all from ancient memory...let's see if I remember correctly): * Sealed chamber: controls high-pass filter. The larger this chamber is, the lower your HP f3 will be and the lower the mechanical power handling will be for the enclosure. Conversely, shrinking this chamber will increase your HP f3 and increase mechanical power handling. * Ported chamber: controls the overall efficiency and bandwidth of the system. Increasing the size of this chamber (while keeping the tuning frequency constant) will make for a narrower passband with a smoother frequency response, though if you get too narrow it'll look like Mt. Fuji--a single peak in the middle of the band. Shrinking this chamber (again, keeping the fb constant) will result in a wider passband and the double-peak response curve you described. * The port: controls the center point of the passband. Increasing the tuned frequency will shift the curve to the right (up the audio spectrum) and decreasing the fb will shift the curve to the left. It's important to note that designing a SRBP's is a lot like flying an old-skool helicopter. In an older helicopter (one without all the modern computers), changing one control (e.g. speed of the rotor) requires changes to the others to keep you from losing control of the craft. The same is true in a SRBP--changing the port, for instance, will not only change the high pass f3, but it'll also change the shape of the response curve, so it's not like you can just simply tune lower and get the same response curve just at lower registers. If you attempt to design a bandpass enclosure sans computer software, you are either really macho or really naive...I'm not sure which. I surely would never want to try it without good modeling software! -dan |
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