port location effects?

[cshaw 10+ year member]

so, im currently redesigning yet another enclosure for my home theater mains. was wondering what the effects, pros, cons are on port placement. using a 3 inch round port. ive already built 2 test boxes with one sealed, and one ported. ported works great for both music and movies for me. so top near tweeter or on bottom below mid or just rear firing? pros cons?

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[cshaw 10+ year member]

wwweeeeeeeeee!!

 

[cshaw 10+ year member]

for example the 1st test box. thinking of making it taller with the port on the bottom 2 inches away from the mid.

 

[Supergumby5000 5,000+ posts]

too many variables to be able to tell which is going ot perform better. try both, let us know

 

[cshaw 10+ year member]

im starting now. not that worried about it, just wanted to learn. port on bottom, tweet centered at the top rounded edges, stained birch and everything. thanks though.

 

[PV Audio 5,000+ posts]

for example the 1st test box. thinking of making it taller with the port on the bottom 2 inches away from the mid.

Jesus Christ, that is a garbage setup. For reasons that I won't bore you with, never have the port above the tweeter if on the same baffle. Have it either at tweeter level ala Polk or below. You need your tweeter at ear level, not the bass output. If you're not using a tower, you should never want a tweeter to not have at least one mid or woofer below it.

 

[PV Audio 5,000+ posts]

And your thoughts for the 2nd build are what you need.

 

[PV Audio 5,000+ posts]

im starting now. not that worried about it, just wanted to learn. port on bottom, tweet centered at the top rounded edges, stained birch and everything. thanks though.

I wouldn't bother spending money on birch and finishing if you're just learning. It will be a waste of money.

 

[cshaw 10+ year member]

i agreed when i first heard it. tweeter next to the port and so close to the edge doest work. off axis response was crap. to say the least.

im doing this version ported with port on the bottom and a little bit wider and taller.

 

[cshaw 10+ year member]

I wouldn't bother spending money on birch and finishing if you're just learning. It will be a waste of money.

well ive had my hand at a about 6 sub boxes by now ported and sealed, but these are just testers and look like crap, but i think i will work on my finishing with these since their for a good friend. plus he is helping and throwing in for supplies anyway.

but honestly i would not mind if you dont, if you can explain a little bit more on rear vs front ports. i always leave the baffle last so i still can decide later.

 

[Walled_Taurus 10+ year member]

Try one with port building off the wall thats what finally seemed to work on some house boxes i built some time ago. I might add it was with a 10inch woofer though.

 

[PV Audio 5,000+ posts]

well ive had my hand at a about 6 sub boxes by now ported and sealed, but these are just testers and look like crap, but i think i will work on my finishing with these since their for a good friend. plus he is helping and throwing in for supplies anyway.
but honestly i would not mind if you dont, if you can explain a little bit more on rear vs front ports. i always leave the baffle last so i still can decide later.

I'd be glad to when I get back this evening. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[cshaw 10+ year member]

thanks pv audio, any links or something to get me started on research is good enough, i dont need to be spoon feed.

 

[Linkz 10+ year member]

I generally build with the tweeter up top; Followed by the sub port then mids. Then the sub below those. I keep spacing between each component even but not exceeding 3". The mids are all on the same level and spaced a few inches apart. Generally 2 mids (8") one Hf horn and a 15" or 12".

I can post an unfinished example if you want.

 

[cshaw 10+ year member]

so from a little bit of research ive come to understand that around the tuning of the enclosure, there is actual sound output from the port. previously i thought the port only served to move air. the biggest and seemingly only problem with a port on the front baffle is mid range leakage out of the port causing distortion or cancelation at certain frequencies. but understanding these things i wanted to build a set of enclosures with front firing ports to learn from.

anyway, heres where i am working on them in my spare time. my friend opted for flat black instead of my suggested textured fleck stone. i may clear coat the front birch baffle with a semi gloss or stain it once and one clear. what do you guys think?