To port or not to port

Yona1973 · 02-28-2010, 08:59 AM

Well I just built my first speaker cab and I think I've done a decent job. After doing some additional reading I'm not sure if I need to port the back or not. Here is what I have done, the sides, top, and bottom is 7/8 white oak, the baffle and back is 3/4 birch ply cabinet grade. Loaded with a peavey scorpion 12" and a 2" port on the front. All joints are sealed up tight as well as the back. The internal dimetions are 21 1/2 X 17 1/2 X 7 3/4. Just woundering if I need to port the back or if any experianced builders see any inherant problems?

5er driver · 02-28-2010, 12:54 PM

As long as there is a tuned port on the front , it doesn't need a second port on the back.

MartyStrat54 · 02-28-2010, 01:15 PM

How did you decide on how big to make the port? It should be tuned no lower than 60Hz. You can't squeeze blood out of a turnip. Most guitar speakers are toast at 70Hz.

Yona1973 · 02-28-2010, 02:52 PM

the dimentions were copied close to but not exact to a Marshall JCM800 112 cab a friend has. the speaker and port placement was copied from it as well as the port size but I made a few measuring errors and mine has just slightly more airspace. the main reason I guess I'm asking is the cabinet has a beautiful warm sounding tone, but also has a bit more bass than I expected, this may be due in part from the denseness of the white oak, the thickness of the wood used or the fact that it only has a 2" port. where my friends cab he made a new back for his and cut a large opening in the back which might reduce the lower tones. I don't have the knowlage yet or the software to make sure I have enough porting to releave the pressure inside so as not to damage my speaker or effect the sound in a negative way. I have been reading about Qts I think it's called and that needs to fall in a set range to sound correct. Guess I have enough knowlage to be dangerous but not enough yet to make sure I got it right. since the dimentions are slightly off to the larger and the cabinet materials are not the same thickness or kind.

02-28-2010, 08:59 AM	#1 (permalink)
Yona1973 Junior Member Join Date: Dec 2009 Posts: 12	To port or not to port Well I just built my first speaker cab and I think I've done a decent job. After doing some additional reading I'm not sure if I need to port the back or not. Here is what I have done, the sides, top, and bottom is 7/8 white oak, the baffle and back is 3/4 birch ply cabinet grade. Loaded with a peavey scorpion 12" and a 2" port on the front. All joints are sealed up tight as well as the back. The internal dimetions are 21 1/2 X 17 1/2 X 7 3/4. Just woundering if I need to port the back or if any experianced builders see any inherant problems?

02-28-2010, 12:54 PM	#2 (permalink)
5er driver Senior Member Join Date: Dec 2007 Location: St. Augustine, FL Posts: 451	Re: To port or not to port As long as there is a tuned port on the front , it doesn't need a second port on the back. __________________ The 5er Driver's Home Jams Do You Really Think So So I'm No Knight Shit (You Have Me Wondering) Hellbent Coke and Joe Maybe It Will Be Happy For Some Reason On My Way Nice to Meet You (Again) Now Annoying In ((((((Stereo)))))) ............... Plug that beotch in an' let her rip!

02-28-2010, 01:15 PM	#3 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Now in Muskogee, by Tulsa Posts: 18,223	Re: To port or not to port How did you decide on how big to make the port? It should be tuned no lower than 60Hz. You can't squeeze blood out of a turnip. Most guitar speakers are toast at 70Hz. __________________ MARTY MARTIMUS MAXIMUS ONLINE TUBES AND OTHER STUFFHyperlink Wilder modded JCM 2204 (Sold my JMP to Joe.). Many other amps. Strats and Explorer are my main guitars.

02-28-2010, 02:52 PM	#4 (permalink)
Yona1973 Junior Member Join Date: Dec 2009 Posts: 12	Re: To port or not to port the dimentions were copied close to but not exact to a Marshall JCM800 112 cab a friend has. the speaker and port placement was copied from it as well as the port size but I made a few measuring errors and mine has just slightly more airspace. the main reason I guess I'm asking is the cabinet has a beautiful warm sounding tone, but also has a bit more bass than I expected, this may be due in part from the denseness of the white oak, the thickness of the wood used or the fact that it only has a 2" port. where my friends cab he made a new back for his and cut a large opening in the back which might reduce the lower tones. I don't have the knowlage yet or the software to make sure I have enough porting to releave the pressure inside so as not to damage my speaker or effect the sound in a negative way. I have been reading about Qts I think it's called and that needs to fall in a set range to sound correct. Guess I have enough knowlage to be dangerous but not enough yet to make sure I got it right. since the dimentions are slightly off to the larger and the cabinet materials are not the same thickness or kind.

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