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Car Forum / Driving, Maintenance, Tuning / Car Audio / April 2004Sub enclosure, sealed, ported, what!?
What is the biggest differance btw the diff type of sub enclosers? Not just those two, I believe there is one more I can't think of at the moment, lets say I'm going for two JLaudio w6 v2's, in the trunk of a 96Avenger ES...? What will each kind do? Maybe someoene will answer me this time! :+) Jk Thanks Buckshot >What is the biggest differance btw the diff type of sub enclosers? Not just >those two, I believe there is one more I can't think of at the moment, lets A couple points. Drivers for sealed tend to have lower efficiency and lower resonance. Ported drivers tend to have at least 3 dB more efficiency and higher resonance. Sealed enclosures will have a gradual low dropoff point, and ported ones the opposite.Ported boxes can have various sizes and tunning methods, and can sound more different in low response Q's. There are more variables here. greg "Buckshot" Jasonc87@comcast.BLAHnet wrote: >What is the biggest differance btw the diff type of sub enclosers? Not just >those two, I believe there is one more I can't think of at the moment, lets [quoted text clipped - 3 lines] >Thanks >Buckshot Here's the basic deal; a 10-inch or larger driver with good stroke in a smaller sealed enclosure can deliver 120 dB SPl at the driver position in a smaller car. If that same woofer is ported in a similar sized box (usually tuned to around 30 Hz) one can get 6-10 dB more SPL in the vicinity of the tuned frequency of the system at the expense of MUCH lower output below the tuned system frequency. A further disadvantage of the ported enclosure is that the driver is un-loaded by the air trapped inside a sealed box and you'll often need a high-pass filter to protect the driver from noise/damage when you play programs with program content below the tuned frequency of the system. > A further disadvantage of the ported enclosure is that the driver is un-loaded > by the air trapped inside a sealed box and you'll often need a high-pass filter > to protect the driver from noise/damage when you play programs with program > content below the tuned frequency of the system. Come now Mr. Nousaine, If people did this many speaker manuf would go out of buisness! While mentioning this to people I usually get a "Deer in Headlights" look, sometims sobbing while saying you mean I have to make a sacrifice at 30Hz to get 6 more dB? I guess you can't have your cake and eat it too! This is a VERY valid point, everyone with a vented enclosure should do this, let me rephrase, if you do not HPF vented enclosures you are doing it wrong! The box ain't makin noise below the tuning freq, why waste the power trying? I work in an industry where we HAVE to HPF subs or things get costly quick, do it and you won't look back, you may even notice you system developing more (gasp) low end with more coherence. Chad > What is the biggest differance btw the diff type of sub enclosers? Not just > those two, I believe there is one more I can't think of at the moment, lets [quoted text clipped - 3 lines] > Thanks > Buckshot The tuned port is to add resonation (the same way a jug resonates) where the power would normally drop off or cause speaker cone over excursion. The downside is that it's just a big hole below the resonant frequency. In most cases you won't want a ported enclosure for a car sub. Car sub enclosures are undersized so you can't place the resonation where it would sound good. It ends up booming in the midbass, buzzing from air turbulence, and leaking away the lowest frequencies. Tuned ports are better for home subs. The enclosure can be large enough to tune the resonance in the 30 to 15 Hz area. The speaker might even need the resonance to control excursion. When you can tune a sub to 20 Hz, it doesn't matter that everything below that is completely lost. >The tuned port is to add resonation (the same way a jug resonates) where >the power would normally drop off or cause speaker cone over excursion. >The downside is that it's just a big hole below the resonant frequency. Huh? The power drops off in a sealed enclosure? >In most cases you won't want a ported enclosure for a car sub. Car sub >enclosures are undersized so you can't place the resonation where it >would sound good. It ends up booming in the midbass, buzzing from air >turbulence, and leaking away the lowest frequencies. Car sub enclosures are undersized? What on earth are you talking about? >Tuned ports are better for home subs. The enclosure can be large enough >to tune the resonance in the 30 to 15 Hz area. The speaker might even >need the resonance to control excursion. When you can tune a sub to 20 >Hz, it doesn't matter that everything below that is completely lost. Does it seem to anyone else like this guy just took a bunch of random words he heard at his local car audio shop, and strung them together for the purpose of this post? My head hurts after reading this. Nick > >The tuned port is to add resonation (the same way a jug resonates) where > >the power would normally drop off or cause speaker cone over excursion. > >The downside is that it's just a big hole below the resonant frequency. > > Huh? The power drops off in a sealed enclosure? What he is saying is that as the frequency drops, so does the volume and it does this gradually in a sealed box. Whereas in a ported box it is tuned for a certain frequency, say 30 hz which will be the loudest and after that the volume drops off a lot more compared to say a sealed box. > >In most cases you won't want a ported enclosure for a car sub. Car sub > >enclosures are undersized so you can't place the resonation where it > >would sound good. It ends up booming in the midbass, buzzing from air > >turbulence, and leaking away the lowest frequencies. > > Car sub enclosures are undersized? What on earth are you talking about? He's referring to the box being small that the sub is in. > >Tuned ports are better for home subs. The enclosure can be large enough > >to tune the resonance in the 30 to 15 Hz area. The speaker might even [quoted text clipped - 8 lines] > > Nick Basically what you should know to avoid confusion is that a sealed box plays more accurately and is generally for sound quality. Ported boxes are more for SPL. Generally speaking rock and such sounds better in a sealed box, whereas rap and r&b and similar music sound better in ported. Hope this helps, Robbie >What he is saying is that as the frequency drops, so does the volume and it >does this gradually in a sealed box. Whereas in a ported box it is tuned >for a certain frequency, say 30 hz which will be the loudest and after that >the volume drops off a lot more compared to say a sealed box. I know exactly what he is trying to say, but he didn't say that at all. He said the power dropped, which is not the case, and could mislead someone who didn't understand what he's talking about. This guys does this alot I've noticed. >He's referring to the box being small that the sub is in. And what does that mean? If I have a sub that is designed for a 2.5 cubic feet sealed enclosure, and I have it in a 2.5 cubic feet sealed box, how is that box undersized? >Basically what you should know to avoid confusion is that a sealed box plays >more accurately and is generally for sound quality. Ported boxes are more >for SPL. Generally speaking rock and such sounds better in a sealed box, >whereas rap and r&b and similar music sound better in ported. I'm quit familiar with the general differences between ported and sealed boxes. Nick Blah sorry bout that I thought it was the original poster replying. I was going on too few hours of sleep last night but anywho. I'm well aware you know what you're talking about, I just thought I was replying to someone else. In fact I think you answered a few of my questions before but eh I'm still learning. > >He's referring to the box being small that the sub is in. > > And what does that mean? If I have a sub that is designed for a 2.5 cubic feet > sealed enclosure, and I have it in a 2.5 cubic feet sealed box, how is that box > undersized? He wasn't very clear but I took it to mean that you can't have a box in a car as big as you POSSIBLY could in a home theater but who knows. Robbie ....snip to content..... >In most cases you won't want a ported enclosure for a car sub. Car sub >enclosures are undersized so you can't place the resonation where it >would sound good. It is true that ported car subwoofers are often tuned to around 30 Hz and many owners want boosted output in the 30-50 Hz area for whatever purposes. However, if you examine enclosure recommendations provided by manufacturers you'll see that ported enclosures are almost always larger than recommended sealed enclosures. >Tuned ports are better for home subs. The enclosure can be large enough >to tune the resonance in the 30 to 15 Hz area. There are few commerically available ported home subwoofers tuned to 15 Hz. Indeed there are exactly none that have useful output below 15 Hz. Most are tuned to 25-30 Hz. Some even higher. The speaker might even >need the resonance to control excursion. When you can tune a sub to 20 >Hz, it doesn't matter that everything below that is completely lost. The term 'completely lost' needs examination; the difference is that a sealed enclosure naturally rolls of at 12 dB per octave below the resonant frequency of the system. A small sealed box usually has an Fsb somewhere between 45 and 60 Hz which is a good match for the cabin gain of a small listening room like a car where there is 12 dB per octave reinforcement as frequency falls. This enables a 10-inch high stroke woofer in a .75-1.0 ft3 sealed enclosure to generate 115-120 dB SPL @ 10 Hz with less than 10% distortion. A ported enclosure falls off at 24 dB per octave below the system tuning frequency effectively off-setting cabin gain below that frequency. While one can tune a system so final resaponse is acoustically flat not many do. Instead the typical system is designed with 6-10 dB of increased SPL at and just above the tuning frequency. But not everything is 'completely' lost below the tuning frerquency. As you mention another large problem with ported systems is port noise. With small enclosures and small port diamaters it's often hard to keep the port from grunting, puffing or making otherwise unpleasant noises. And, of course, there's the possibility of driver noises and damage if the driver itself isn't designed properly or the system appropriately high passed electronically. Thanks for the responses. With all this said what do you all think I should do for two twelves, I don't know what kind, or anyhting right now so its open for suggestions still. Anyways 2 12's in the trunk of a small-midsize car, Ported or sealed? Together or seperate? I was kinda thinkin of gettin creative with my enclosure Ill make some pictures of it, and post them, but I dont know what to do! Buckshot > What is the biggest differance btw the diff type of sub enclosers? Not just > those two, I believe there is one more I can't think of at the moment, lets [quoted text clipped - 3 lines] > Thanks > Buckshot I believe that the general concensus is ... the best box for you depends on your listening tastes. More info please ... also, if you plan on building the enclosure yourself, are you willing to try building a ported? > Thanks for the responses. With all this said what do you all think I should > do for two twelves, I don't know what kind, or anyhting right now so its > open for suggestions still. Anyways 2 12's in the trunk of a small-midsize > car, Ported or sealed? Together or seperate? I was kinda thinkin of gettin > creative with my enclosure Ill make some pictures of it, and post them, but > I dont know what to do! >I believe that the general concensus is ... the best box for you depends >on your listening tastes. More info please ... also, if you plan on building >the enclosure yourself, are you willing to try building a ported? I listen to MOSTLY Rock, and Rn'B, with ocasional country. I would most definitly be interested in trying to build a ported box if I could get maybe some general directions from somewhere. My tastes for the sound, aren't necesarilly LOUD, but good DEEP base that sounds well in the cabin. I would even be possibly interested in trying to work with fiberglass so I could keep most of my trunk space. I originally said two twelves, but two tens would be easier to tuck I think, I dunno waht to do. I kinda liked a design I saw on the JL Audio site. What subs are good sounding subs, and what do you think would give me solid deep base, but doesnt have to be the loudest car around? http://www.jlaudio.com/Gallery/Installdetail.cfm?Action=3&Veh_ID=626 << That setup I thought looked clean and Nice. >I believe that the general concensus is ... the best box for you depends >on your listening tastes. More info please ... also, if you plan on building >the enclosure yourself, are you willing to try building a ported? I listen to MOSTLY Rock, and Rn'B, with ocasional country. I would most definitly be interested in trying to build a ported box if I could get maybe some general directions from somewhere. My tastes for the sound, aren't necesarilly LOUD, but good DEEP base that sounds well in the cabin. I would even be possibly interested in trying to work with fiberglass so I could keep most of my trunk space. I originally said two twelves, but two tens would be easier to tuck I think, I dunno waht to do. I kinda liked a design I saw on the JL Audio site. What subs are good sounding subs, and what do you think would give me solid deep base, but doesnt have to be the loudest car around? http://www.jlaudio.com/Gallery/Installdetail.cfm?Action=3&Veh_ID=626 << That setup I thought looked clean and Nice. |
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