Sealed Versus Ported
07-24-2004, 07:18 PM
#22
Guest
Posts: n/a
As you move higher in frequency from the tuning frequency a ported box behaves more and more like a sealed box. This is direct from Mark ***uda of Rockford during RTTI training. I personally prefer the SBB4 alignment as it provides very flat frequency response yet has whiat I call "area under the curve" It plays very low and stays pretty flat.
07-24-2004, 07:35 PM
#23
Goalie Man
Join Date: May 2003
Posts: 1,412
i have met mark and bashed out this topic with him in depth. smart man but what i boiled down to was this.. a properley designed and built ported box, built exclusively for a specific vehicle, will always outperform a sealed box. to this i agree, but......... my point is sealed is easier to build, and there are far more drivers that will fit the box, and we dont have to worry about a subsonic filter and we can have a varience of up to 25% and still have excellent results. lets see as an installer do i really want to spend two to three weeks measuring the car, finding the transfer function of the vehicle getting its exact aqustical responce once a ported enclosure is put in it, remember the car will act as a sealed chamber creating in essence a band pass design, so now we have to factor in air mass loss do to leaks in the vehicle!!! holy crap batman, as mark says , ported is the way to go, easier to build no. and i cant argue with him on that. he never ever lost.. and as he puts its, if its going to be done right, why do anything other that which is perfection. last point i really dont care to show my car off on the internet, if you are curious and want to see it, you know where i work, or even better come to a usaci show and i will gladley show it to you. i have been at dave oakleys show and the stoon show and am registed for kamloops calgary and portland. hope to see you there, promise i will buy you a drink.
07-24-2004, 07:43 PM
#24
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Posts: n/a
Ok but if the vehicle is creating a bandpass, it is doing it with either a ported or sealed box so that part gets thrown out. Yes you can misize the box quite a bit if it's sealed but why would anybody that owns a tape measure misize a box by 25%? The only huge advantage a sealed box has over ported is it's size and in many applications sealed is the best answer, but for me and most of my customers it's because a ported box simply won't fit. I build ported boxes probably two to three times as much as sealed. I used sealed in all my previous personal systems except for 2. I will be using sealed in my SX 2.0 because I need as much trunk space as possible, but my Beetle which will be an SQ comp car I am going ported.
07-24-2004, 07:45 PM
#25
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^ So you like sealed because you can build quick, sloppy size boxes and throw random woofers in it? Interesting.
Yeah - that sounds lame but so does all that crap about air mass loss and transfer function. [img]graemlins/jack.gif[/img] Why would one need to figure it for vented but not sealed? That's right, they wouldn't.
A subsonic filter is not required in any system but benefits most of them.
Lets try to stick to reality.
Yeah - that sounds lame but so does all that crap about air mass loss and transfer function. [img]graemlins/jack.gif[/img] Why would one need to figure it for vented but not sealed? That's right, they wouldn't.
A subsonic filter is not required in any system but benefits most of them.
Lets try to stick to reality.
07-25-2004, 09:12 AM
#27
Originally posted by Dukk:
We did some testing the other day in a car - the dude got over 4db "free" by adding a vent to his sealed enclosure
We did some testing the other day in a car - the dude got over 4db "free" by adding a vent to his sealed enclosure
Still never heard of that much of an increase from just adding a port, though.... [img]graemlins/dunno.gif[/img]
Anyway... I like ported boxes, ported low for SQ... ported high for SPL... but my overall preference for in car SQL are large sealed boxes....
07-25-2004, 10:37 AM
#28
Goalie Man
Join Date: May 2003
Posts: 1,412
lets see i like to build a quick box ok. sloppy size??? what the heck does that mean, oh ya anything under 1ft cubes is sloppy and anything above is tidy.. come on paul give me a break. your smarter than that!! and throw random woofers in. sorry again but i cant build my customer a box unless i know what driver they have! that way i can play with the drivers thiele small parameters to get the best results out of the sealed box. (unless the driver is specifically made for ported, ie avi or cerwin vega ect.) i think we are getting alittle to touchy on this one. so again i like ported boxes but for me , thats me, i strongley recommed to people who want good sound on a resonable budget go sealed, ported just takes to much time and it pretty much hit or miss. lets be honest, no matter what box design you choose, all the computer programs that we have at our disposal, i dont know of any that can factor in the actual interior of the car itself. which as you know will greatley affect the overall effect of the said box. so all things being equal sealed is by far the least effected by internal car volumes and thus works more often than not.
07-25-2004, 01:50 PM
#29
Originally posted by Haunz:
</font><blockquote>quote:</font><hr />Originally posted by Dukk:
We did some testing the other day in a car - the dude got over 4db "free" by adding a vent to his sealed enclosure
</font><blockquote>quote:</font><hr />Originally posted by Dukk:
We did some testing the other day in a car - the dude got over 4db "free" by adding a vent to his sealed enclosure
Still never heard of that much of an increase from just adding a port, though.... [img]graemlins/dunno.gif[/img]
</font>[/QUOTE]The 'cabin loading' was already there as the sealed box was already in the car. The box already had a slot port in it that was covered over when the put the new woofers in. They metered the car as sealed. Uncovered the ports and metered again. 4 dB gain. Yep, it was all in the port.
07-25-2004, 03:04 PM
#30
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Posts: n/a
Originally posted by quart man:
lets see i like to build a quick box ok. sloppy size??? what the heck does that mean, oh ya anything under 1ft cubes is sloppy and anything above is tidy.. come on paul give me a break. your smarter than that!! and throw random woofers in. sorry again but i cant build my customer a box unless i know what driver they have! that way i can play with the drivers thiele small parameters to get the best results out of the sealed box. (unless the driver is specifically made for ported, ie avi or cerwin vega ect.) i think we are getting alittle to touchy on this one. so again i like ported boxes but for me , thats me, i strongley recommed to people who want good sound on a resonable budget go sealed, ported just takes to much time and it pretty much hit or miss. lets be honest, no matter what box design you choose, all the computer programs that we have at our disposal, i dont know of any that can factor in the actual interior of the car itself. which as you know will greatley affect the overall effect of the said box. so all things being equal sealed is by far the least effected by internal car volumes and thus works more often than not.
lets see i like to build a quick box ok. sloppy size??? what the heck does that mean, oh ya anything under 1ft cubes is sloppy and anything above is tidy.. come on paul give me a break. your smarter than that!! and throw random woofers in. sorry again but i cant build my customer a box unless i know what driver they have! that way i can play with the drivers thiele small parameters to get the best results out of the sealed box. (unless the driver is specifically made for ported, ie avi or cerwin vega ect.) i think we are getting alittle to touchy on this one. so again i like ported boxes but for me , thats me, i strongley recommed to people who want good sound on a resonable budget go sealed, ported just takes to much time and it pretty much hit or miss. lets be honest, no matter what box design you choose, all the computer programs that we have at our disposal, i dont know of any that can factor in the actual interior of the car itself. which as you know will greatley affect the overall effect of the said box. so all things being equal sealed is by far the least effected by internal car volumes and thus works more often than not.
