Mobile Chassis Dyno Posted January 30, 2011 Report Share Posted January 30, 2011 Guys, I have used both the search function and google to try and educate myself about the differences in displacement requirements for sealed and ported enclosures. Why is it that a ported enclosure is typically double the displacement compared to a sealed enclosure for any given subwoofer. Obviously this is the way it works. I just want to understand how a ported enclosure needs so much more displacement over a sealed enclosure. My only guess is it has something to do with how the sound waves travel inside the enclosure. Also when talking about RMS power. Is this rating typically the same for both ported and sealed or can we figure on an increased power handling for a sealed enclosure providing we do not overheat the coil? Be easy on my guys. I tune 1000 horsepower twin turbo mustangs and vettes. When it comes to enclosures I admit the only thing I know how to build is sealed enclosure. Quote Warm Regards, Dyno Brian 1997 Ford Probe |Sony Head Unit|Alpine V12 AccuClass-D MRD M1000 Amplifier|4 RE AUDIO SRX12D4 12's|Mids and Highs coming soon!| |1998 Mustang GT Twin Turbo|1986 Mustang GT Single Turbo|1996 Mustang Mystic Cobra N20|1995 Mustang Cobra 5,000 miles| 2002 ZO6 Link to comment Share on other sites More sharing options...
Freshman6969 Posted January 30, 2011 Report Share Posted January 30, 2011 holy fuck an actual intelligent question? wow free bump for you sir Quote Legal TL scores145.6 on the dash sealed up in the low 40hz area with the port out145.5 on the dash sealed up @30hz with the port inless then 1k clamped on a 3.5k! Why would you EVER WANT flex?huh?...flex is what can make the lows lower and more air being pushed correct? My FeedbackJeep-BuildlogPT LOSER buildlog Link to comment Share on other sites More sharing options...
Mobile Chassis Dyno Posted January 30, 2011 Author Report Share Posted January 30, 2011 holy fuck an actual intelligent question? wow free bump for you sir I am trying. When it comes to something I do not understand it is better to ask those who have been doing this for a long time and have a good reputation regarding the question being asked. Quote Warm Regards, Dyno Brian 1997 Ford Probe |Sony Head Unit|Alpine V12 AccuClass-D MRD M1000 Amplifier|4 RE AUDIO SRX12D4 12's|Mids and Highs coming soon!| |1998 Mustang GT Twin Turbo|1986 Mustang GT Single Turbo|1996 Mustang Mystic Cobra N20|1995 Mustang Cobra 5,000 miles| 2002 ZO6 Link to comment Share on other sites More sharing options...
AMI CUSTOMS Posted January 30, 2011 Report Share Posted January 30, 2011 You have to account for the port in the displacement. That is as simple as it gets. And sealed allows the sub to load properly so you get an increase in handling, this is why 4th orders are so damn loud. LOL Quote TEAM SOUNDQUBED -- TEAM SOUTH TEAM S.O.B. - Founder & Captain 3x Streetbeat World Record Holder 2017 MWSPL 1st place Mayhem & 4th Xtreme 4 2016 MWSPL 1st place Mayhem/2nd Adv 4/2nd Xtreme 4 2015 MWSPL 2nd place Mayhem & 4th Xtreme 4 2014 USACI 2nd place Streetbeat 5 - 162.6 db 2014 MWSPL 2nd place Xtreme 4 - 144.9 db 2013 USACI 1st place Streetbeat 4 - 161.9 db 2013 USACI 1st place Street Q+ - 162.8 db 2013 MWSPL 3rd Kaos2 & 4th Xtreme 4 2011 USACI 2nd place MOD 1001-2k - 160.0 db 2011 MWSPL 4th place: Adv3 - 157.8 db, Kaos2 - 150s db, Xtreme4 - 140s db 2010 ARSPL 1st place 501-750 - 160.3 db Arkansas loudest Best score to date 164.4 db - Termlab Outlaw Streetbeat 4 - 161.9 db Streetbeat 5 - 162.6 db MWSPL on Dash Legal door open (Music) - 162.5 db Sealed on dash Legal (Music) - 161.1 db - Termlab THE BLACK NASTY CURRENT BUILD & FAB The Black Nasty (6) 15 Rebuild Log 2012 (4) 15 Walled Sierra Build Log Evo X build log Facebook page The Black Nasty Link to comment Share on other sites More sharing options...
AMI CUSTOMS Posted January 30, 2011 Report Share Posted January 30, 2011 What I mean to as you might not realize is in a ported enclosure, lets say then inter dimensions of the port are 12 x 12 x 12 so that is 1 cubic ft, that subtracts from the displacement along with the subs and bracing. Quote TEAM SOUNDQUBED -- TEAM SOUTH TEAM S.O.B. - Founder & Captain 3x Streetbeat World Record Holder 2017 MWSPL 1st place Mayhem & 4th Xtreme 4 2016 MWSPL 1st place Mayhem/2nd Adv 4/2nd Xtreme 4 2015 MWSPL 2nd place Mayhem & 4th Xtreme 4 2014 USACI 2nd place Streetbeat 5 - 162.6 db 2014 MWSPL 2nd place Xtreme 4 - 144.9 db 2013 USACI 1st place Streetbeat 4 - 161.9 db 2013 USACI 1st place Street Q+ - 162.8 db 2013 MWSPL 3rd Kaos2 & 4th Xtreme 4 2011 USACI 2nd place MOD 1001-2k - 160.0 db 2011 MWSPL 4th place: Adv3 - 157.8 db, Kaos2 - 150s db, Xtreme4 - 140s db 2010 ARSPL 1st place 501-750 - 160.3 db Arkansas loudest Best score to date 164.4 db - Termlab Outlaw Streetbeat 4 - 161.9 db Streetbeat 5 - 162.6 db MWSPL on Dash Legal door open (Music) - 162.5 db Sealed on dash Legal (Music) - 161.1 db - Termlab THE BLACK NASTY CURRENT BUILD & FAB The Black Nasty (6) 15 Rebuild Log 2012 (4) 15 Walled Sierra Build Log Evo X build log Facebook page The Black Nasty Link to comment Share on other sites More sharing options...
nCOMP1337 Posted January 30, 2011 Report Share Posted January 30, 2011 I wish I could help ya, but it is a relief when there is a question that isnt a person fairly new to car audio trying top get others to do work for them Quote Link to comment Share on other sites More sharing options...
Mobile Chassis Dyno Posted January 30, 2011 Author Report Share Posted January 30, 2011 You have to account for the port in the displacement. That is as simple as it gets. And sealed allows the sub to load properly so you get an increase in handling, this is why 4th orders are so damn loud. LOL Damn, I can not believe I did not think of taking port displacement into account. That makes a world of sense to me. Thank you for the reply. Care to explain more why a 4th order is "loud"? If not I will get back to google and put my fingers to work to find the answer. Not sure what Transmission Line is considered. I had a customer come to my shop who had 4 8's in a T line and was blown away how much louder it was then my 4 12's sealed. Thank you again. Quote Warm Regards, Dyno Brian 1997 Ford Probe |Sony Head Unit|Alpine V12 AccuClass-D MRD M1000 Amplifier|4 RE AUDIO SRX12D4 12's|Mids and Highs coming soon!| |1998 Mustang GT Twin Turbo|1986 Mustang GT Single Turbo|1996 Mustang Mystic Cobra N20|1995 Mustang Cobra 5,000 miles| 2002 ZO6 Link to comment Share on other sites More sharing options...
AMI CUSTOMS Posted January 30, 2011 Report Share Posted January 30, 2011 (edited) You have to account for the port in the displacement. That is as simple as it gets. And sealed allows the sub to load properly so you get an increase in handling, this is why 4th orders are so damn loud. LOL Damn, I can not believe I did not think of taking port displacement into account. That makes a world of sense to me. Thank you for the reply. Care to explain more why a 4th order is "loud"? If not I will get back to google and put my fingers to work to find the answer. Not sure what Transmission Line is considered. I had a customer come to my shop who had 4 8's in a T line and was blown away how much louder it was then my 4 12's sealed. Thank you again. 4th order? It is basically both boxes combined, it is a sealed chamber that the subs are in and on front of that is a ported chamber, the ratio of ported cubes to sealed cubes determines the output and it is basically the best of both worlds, only thing is a 4th order for just one 15 is huge generally 15+ cubes. And T-line is just a box with a very long ass port more or less. Edited January 30, 2011 by AMI CUSTOMS Quote TEAM SOUNDQUBED -- TEAM SOUTH TEAM S.O.B. - Founder & Captain 3x Streetbeat World Record Holder 2017 MWSPL 1st place Mayhem & 4th Xtreme 4 2016 MWSPL 1st place Mayhem/2nd Adv 4/2nd Xtreme 4 2015 MWSPL 2nd place Mayhem & 4th Xtreme 4 2014 USACI 2nd place Streetbeat 5 - 162.6 db 2014 MWSPL 2nd place Xtreme 4 - 144.9 db 2013 USACI 1st place Streetbeat 4 - 161.9 db 2013 USACI 1st place Street Q+ - 162.8 db 2013 MWSPL 3rd Kaos2 & 4th Xtreme 4 2011 USACI 2nd place MOD 1001-2k - 160.0 db 2011 MWSPL 4th place: Adv3 - 157.8 db, Kaos2 - 150s db, Xtreme4 - 140s db 2010 ARSPL 1st place 501-750 - 160.3 db Arkansas loudest Best score to date 164.4 db - Termlab Outlaw Streetbeat 4 - 161.9 db Streetbeat 5 - 162.6 db MWSPL on Dash Legal door open (Music) - 162.5 db Sealed on dash Legal (Music) - 161.1 db - Termlab THE BLACK NASTY CURRENT BUILD & FAB The Black Nasty (6) 15 Rebuild Log 2012 (4) 15 Walled Sierra Build Log Evo X build log Facebook page The Black Nasty Link to comment Share on other sites More sharing options...
Mobile Chassis Dyno Posted January 30, 2011 Author Report Share Posted January 30, 2011 A friend of mine who is pretty sharp in building ported enclosures is offering to both design and build an enclosure for me for free so I can see the difference between ported vs sealed. All I have to do is buy the materials. This is really tempting considering the fact my answer to increased SPL is to add cone area and more power. I have been telling him I want to go from my 4 12's and 1000 watts of RMS power to 4 15's and 3000 watts of rms (Staying sealed). He said why bother spending that kind of money when I can get you louder with just an enclosure. I think I am going to give him the green light and build me an enclosure. I am probably the only dyno shop in the country who owns a twin sensor term lab and does not do any car audio installs. LOL. Quote Warm Regards, Dyno Brian 1997 Ford Probe |Sony Head Unit|Alpine V12 AccuClass-D MRD M1000 Amplifier|4 RE AUDIO SRX12D4 12's|Mids and Highs coming soon!| |1998 Mustang GT Twin Turbo|1986 Mustang GT Single Turbo|1996 Mustang Mystic Cobra N20|1995 Mustang Cobra 5,000 miles| 2002 ZO6 Link to comment Share on other sites More sharing options...
Ray Posted January 30, 2011 Report Share Posted January 30, 2011 Sorry I missed this.. In a sealed box you are only hear the front wave of the speaker.. Kind of like how a piston on has compression at tdc Imagine if a piston would build compression on both the up and down stroke.. Same theory, kind of.. With porter you are able to "hear" both the front and back wave. In theory, 2 of your 12's in a potted box, will be just as loud as 4 in your sealed box. Quote 2008 California state record holder 157.2 Bassrace2009 California state record holder 157.0 BassraceRollin 50's 158.7db2009 King of Cali Bassrace2009 USACi score 160.5 @ 42hz Link to comment Share on other sites More sharing options...
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