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box-less
Dodge Dakota
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3/24/2003
12:45:59
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 Subject: slotted vs. ported
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First off, this may be long, sorry
I actually have a few questions.
1.What is better, and why, slotted enclosure or ported? Or is it just a personal thing?
2. When you are building a slotted box, how do you figure the cube in, since the box isn't sealed on all sides? And, does the slot size matter?
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conig
Dodge Dakota
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3/24/2003
16:24:04
|  RE: slotted vs. ported
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a slot is basically a square or rectangle port. yes you need to figure the dispacement of the slot into the enclosure when building it.
I've run ported and slotted in my opinion a slot is better I get virtually no port noise at all with my current set up. on occasion though I can hear the voicecoils working. on that eastside boys song i don't give a f%$# I can hear the coils in the middle of the song were the song slows down. I'ts kindof cool though because the subs are moveing real slow and real far but no noise comes out of them.lol
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JMII
Dodge Dakota
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3/24/2003
19:47:39
|  RE: slotted vs. ported
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What conig said is true - slotted is better if you can do it because it can reduce the port noise greatly.
"the subs are moveing real slow and real far but no noise comes out of them"
Well... that is because the frequencies are too low for your box to reproduce. I'm kind of shocked you have not blown a woofer yet! The Hz comming from the amp are lower than the Hz your box is ported/tuned to. You should consider putting a sub-sonic filter on your set-up as ALL ported (or slotted) boxes should have one to protect the subs from ultra low bass.
- John
http://home.mindspring.com/~jntmoore/truck/home.html
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conig
Dodge Dakota
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3/25/2003
11:19:08
| RE: slotted vs. ported
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wow didn't know that. weres a good place to get a filter.
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lowdaksport
Dodge Dakota
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3/25/2003
12:02:41
| RE: slotted vs. ported
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my class d amp has one built in i think a lot of class d amps do.
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JMII
Dodge Dakota
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3/25/2003
12:06:45
|  RE: slotted vs. ported
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Most of Audio Controls EQs/Pre-Amps and Crossovers have sub-sonic filters on them. Go to www.audiocontrol.com and read up. Not only can the sub-bass damage your speakers it wastes amplifer power pushing sound waves you can't even hear because they are too low.
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conig
Dodge Dakota
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3/25/2003
13:34:36
| RE: slotted vs. ported
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my amp has a crossover. its an alpine mrv 1507. now that im confused I thought that the crossover blocks frequencys above were you have the crossover set. EX-if I set the crossover at 60hz i only lets frequencys under 60hz to the subs.
or is it vise versa? I'm starting to question my knowledge now and feel dumb with all the stereos I've put together in cars.
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JMII
Dodge Dakota
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3/25/2003
19:30:10
| RE: slotted vs. ported
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Depends on the type of crossover:
High pass lets frequencies above go on to the amp whiile at the same time it blocks the lower ones. A low pass filter or crossover does the opposite. Most crossover are two-way (like the ones used in components - between mids and tweeters) with a high & low side - from a fixed or adjustable Hz.
It's pretty fool-proof because you'd know if it was the wrong once hooked up as you mids would muffed by too much bass and subs would not hit as they were getting almost no bass at all :)
Keep in mind a crossover does not complete block the frequencies... it just lowers them gradulately as you get further from the setting - this is the slope of the crossover. For example a 12dB/octave slope is pretty soft compared to a 36dB/octave filter which would be good for a subsonic filter since it's so steep. Slopes are 6, 12, 18, 24 & 36 dB per octave - with 12 being the most common.
120 to 80Hz is a good area for setting between your subs and your mids depend on speaker size (bigger mids like 6.5" can handle some low bass). Next a subsonic filter set at somewhere between 18 to 42Hz depending on your box/speaker/amp/crossover slope combination. Sealed boxes can handled (and thus produce) the deeper/lower bass so you can go without a filter on them, but your really just wasting amplifer power and pushing the speaker hard for no reason.
Some people go crazy trying to get thier systems to hit super low like at 20Hz only to find out you can't hear that low anyway. But you can FEEL it... thats for sure :) it takes your breath away!
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matt
Dodge Dakota
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1/21/2005
14:27:19
| RE: slotted vs. ported
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i have a slotted box for to 12's (MTX thunder 4000) there rated at 200 RMS @ 4 Ohms
i'm using them in my house the amp i'm using is an 1970's ventage sansui 9090db Worth about 300 on ebay
its rated at only 100 watts @ 8 ohms per channal
since i can only hook up 8 ohms to it i run the to subs in series i can make my voice coils pop (the sub is bottoming out) but it does only with sub sonic frequencies like the HALO one soundtrack #15 (word of causion to anyone you might try)
i think slotted is way better cuz it will pruduce a better frequencies cerve throust all the frequencies you set for the sub i listen to Rock Rap and Techno so i need a box that will sound good for all of it and it does
for those who like to built there own boxes slotted is easy but you can also tune the box by cutting the secendary wall instide the box
sence my amp is 100 and my speakers are 400 i took the secondary wall completly out sounded alot better
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