sealed box sounds to small (Alpine Type X
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=59864
Printed Date: April 23, 2024 at 1:09 PM
Topic: sealed box sounds to small (Alpine Type X
Posted By: casaus19
Subject: sealed box sounds to small (Alpine Type X
Date Posted: July 22, 2005 at 8:24 AM
i just made a sealed box for an alpine type "X" 12 for a ford mustang convertible. i made the box to what the recomended specs showed(still learning box sizes) and the box barely fits in the trunk. when we hooked it up it sounds like it does not have enough airspace. and i can't make it much bigger because of fitment issues. any help on a good volume for that sub or how to make it sound better would be great
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Imagination is more powerfull than knowledge
Replies:
Posted By: oonikfraleyoo
Date Posted: July 22, 2005 at 9:44 AM
I think thats just the way that sub sounds, sorry. I had one for a minute and its a very dissapointing speaker. You could try a ported box, but I'm not sure you could get it to fit if the sealed box barely does. ------------- Nik
Jeeputer Progress
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Posted By: placid warrior
Date Posted: July 22, 2005 at 4:49 PM
how bout adding some polyfill or something, cut a square of it, roll it up and staple it to the corners to keep it as far away from the sub as u can.
Posted By: ss-installer
Date Posted: July 22, 2005 at 11:59 PM
i agree, try tuning the box with polyfill. you do have the amp set on low pass right? what is the frequency set at?
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Posted By: placid warrior
Date Posted: July 23, 2005 at 2:30 AM
yea...if u dont have a crossover or the crossover is set wrong it can sound really cr@ppy too.
Posted By: DYohn
Date Posted: July 23, 2005 at 9:48 AM
What makes you think the enclosure is too small? A small enclosure results in a boomy system that appears to have too strong midbass and less low bass. In a subwoofer crossed over properly at 80Hz or so, this may mean not much output at all, especially if the enclosure is very small. Adding polyfill at a ratio of 1 pound per 1 cuft of enclosure volume will increase the effective size of the enclosue by about 40%. This means a 1 cuft enclosure with 1 pound of acoustic fill will act as a 1.4 cuft enclosure. And the fill should be between the woofer and the back wall of the enclosure for best effect, loosly filled. It does not matter if it touches the woofer, except that in very high powered systems the magnet can get hot and the polyfill may burn... I quickly ran the T/S of that Alpine woofer and it requires a pretty large enclosure. I got 145 litres (5.1 cuft) for a sealed enclosure (resulting in a -12 db/oct slope below 40Hz) or 146.5 litres (5.2 cuft) ported, tuned to 18Hz (4" port 17.25" long) which gave the best performance. Relatively flat down to 30Hz, a +2db port peak at 20Hz and -24 db/oct below that. Impressive. How large is your enclosure? ------------- Support the12volt.com
Posted By: stevdart
Date Posted: July 23, 2005 at 11:45 AM
This thread should be renamed something like "Alpine type X enclosure size" so that searchers can see the info here, DYohn. I know I'd want to find this again if I were looking for some good direction on building a box for these. :)
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: DYohn
Date Posted: July 23, 2005 at 2:23 PM
you got it. ------------- Support the12volt.com
Posted By: casaus19
Date Posted: July 23, 2005 at 11:32 PM
so in this case i am really a newb. the biggest that i could get the box was roughly 1.75 cuft. if that subs needs so much air space how am i gonna be able to do that in the mustang when it was hard enough to get the 1.75 box in the trunk. but those stats are nice to hear thanks.
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Imagination is more powerfull than knowledge
Posted By: DYohn
Date Posted: July 24, 2005 at 9:23 AM
Alpine recomends 1.75 cuft for this woofer? That is entirely too small and will turn this sub into a mid-bass at any normal listening volume. 1.75 cuft is probably being recomended because Alpine knows not many people can put a proper size enclosure in their car, and that car audio power is cheap. If you pump a continuous 2KW into this thing in a small enclosure you may be able to overcome the compliance limitations and create appreciable SPL in the sub frequencies. But if it was me, I'd use this as a killer home theatre sub in a 5.2 cuft ported system with a 500 watt plate amp. That would make those T-Rex footsteps shake the fillings out of your teeth. But in a car, I'd use a different woofer. ------------- Support the12volt.com
Posted By: customsuburb
Date Posted: July 24, 2005 at 10:45 AM
hmm.. when I model the type x 12 in a 1.75 cf sealed box in WinISD it shows a flat response with an F3 of 32 hz. Here is a screenshot showing the graph. https://www.omarnyc.com/uploads/public/New%20Folder%20(10)/WinISD%20screen%20shot.JPG
Posted By: DYohn
Date Posted: July 24, 2005 at 6:06 PM
Interesting. When I put the T/S from Alpine's web site into WinISD and go for default optimized enclosure, I get 5+ cuft. I didn't try to model 1.75. I still think it's make a killer HT sub and not a very efficient car audio sub. Your screen shot won't come up, by the way. ------------- Support the12volt.com
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