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Old 01-11-2004, 07:38 PM   #1
94tegRS
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6th order bandpass

ok, I only had one sub coming and was planning on getting a 2nd one soon. the way my amp is built I would either have about 700 watts RMS to each and with one sub it will get a bit over 1000 watts RMS to the one sub. now I was designing a ported box but went out to build it today and realized I had to shorten it heithwise alot to be able to get it in/out of the trunk and only have room for a mid sized sealed box. but the -3dblines way up at 38.

a sealed box of the same size but with only 1 sub only brings it down to 36.

a ported of this size tuned to 24 and the -3db point is at 24 db, peak is only up 1 db around 38-60db, and the port length required works out perfect for the dimensions I can use to build the box.

but I have been playing with a 6th order bandpass on winisd and have it to where the -3db crossover points are 29 and 98 Hz. and the peak is at +5.4db@42Hz and +5db@72Hz and the peak dips in the middle down to +4@55Hz. I usedn the signal generator through the aux input on my home theater system and I would be fine with that cutoff I think. I like the real lows. I am sure that my home system pounds out the lows nowhere near how my 1000 watt 12" will but I think I got an idea of the performance, plus with that huge peak within the cutoff points means where it does play it will be L-O-U-D! right? I think I am gonna try this box and see what happens but just have a few questions about it. will the box not being designed for the higher bass frequencies but the sub getting them damage the sub at all? I am pretty sure my cd player has a HPF for the speakers that I can set to 120 and then I can probably cross my amp over at about the same and just let the subs handle the LOW LOW's and the sopeakers handle the rest.

and my final question is that what 6th orders are best for, tuning differnet sets of subs/midbass drivers to handle different frequency ranges wihtout expensive electronic crossovers or something??
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Old 01-11-2004, 07:39 PM   #2
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Re: 6th order bandpass

and you dopnt need to say anything if im correct, but im assuming the rear chamber is the chamber that hoiuses the basket.
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-01 R1-04 daytona 600-94 teg RS-95 teg LS
-91 teg RS-92 teg GSR-94 civic CX hatch (3 times)
-94 civic DX-96 civic HX-97 Accord LX-72 superbeetle
-74 beetle-84 silverado-66 c10-74 maverick-78 280z
-84 200sx-86 tercel wagon-95 mustang V6
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Old 01-11-2004, 11:52 PM   #3
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Re: 6th order bandpass

after hours and hours(not an exageration) of refiguring the volume after refiguring the port displacement over and over for both chambers.
I got it setup about the only way possible to fit where I need it to. -3db cutoffs are at 25Hz and 95 HZ and peaks are at +4.5db@36Hz and +6@70Hz and the valley in the peak is +3db@50Hz. not the best plot I guess but I re put on my old box I had built with my old sub and the -3db point is at 30Hz on the old box and first peak is same db jump but @ 40Hz.

and I liked the way it sounded so I guess the slow boomy sound is what I like. I am gonna see what it sounds like soon, Ill have it built tomorrow most likely so ill post a pic of it when its done. I got the 3/4 MDF/plexi/glue/screws/carpet/ports today so I am going at it tomorrow morning.

and one question? all the port doesnt have to be in the chamber correct? the length of the port for tuning accounts for the air inside the port itself, not how much air is inside the port inside the chamber itself, because one chamber needed a longer port than would fit in the chamber, so I have both ports coming from the same face, and the long one for the small chamber goes all the way through the other chamber and then enters the chamber it is for about 8 inches. only way I could get it to work. will that work, if i get a no before i start ill redesign, if not im starting the project and ill see how it works when finished.

and thanks for all the help on this box.
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-01 R1-04 daytona 600-94 teg RS-95 teg LS
-91 teg RS-92 teg GSR-94 civic CX hatch (3 times)
-94 civic DX-96 civic HX-97 Accord LX-72 superbeetle
-74 beetle-84 silverado-66 c10-74 maverick-78 280z
-84 200sx-86 tercel wagon-95 mustang V6
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Old 01-12-2004, 02:03 AM   #4
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Re: 6th order bandpass

man, I was making sure it would work and found out that there wasnt enough room on the middle divider to mount a 12" sub and have a 3" pipe pass through so I just spent another very long time doing more math and got it worked out finally and it will work this time. and now the cutoffs are 23 and 93 Hz, and the paks are even at +5db@ 31 and 71 Hz and the valley drops to +2.25@47 Hz.
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history:
-01 R1-04 daytona 600-94 teg RS-95 teg LS
-91 teg RS-92 teg GSR-94 civic CX hatch (3 times)
-94 civic DX-96 civic HX-97 Accord LX-72 superbeetle
-74 beetle-84 silverado-66 c10-74 maverick-78 280z
-84 200sx-86 tercel wagon-95 mustang V6
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