Did my box design fail me?

[phemps 10+ year member]

How long is that port supposed to be? You do realize that effectively it extends about to where the paint ends on the back wall right?

Im aware that it would have some correction factor but looked like it wasnt gonna change it a whole lot. Do you think im tuned a bit lower than i intended? The port is 23 inches long. outside dimensions are 35.5 inches wide, 14 tall, and 30 deep. port is 12.5 x 6 internal . Sub baffle is doubled

 

[brian84corvette 10+ year member]

i used paint shop super crappy just to give you an idea of what the box might be acting like.

blue is your net.

green is acting like your port

and the red line is your port leingth

do a quick math and see what the numbers come up looking like for port tuning and net volume if indeed the box is acting like its drawin in crappy colors in this pic

 

[hispls 5,000+ posts]

i used paint shop super crappy just to give you an idea of what the box might be acting like.blue is your net.

green is acting like your port

and the red line is your port leingth

do a quick math and see what the numbers come up looking like for port tuning and net volume if indeed the box is acting like its drawin in crappy colors in this pic

More like this... .and even crappier paint skillz.

 

[hispls 5,000+ posts]

Im aware that it would have some correction factor but looked like it wasnt gonna change it a whole lot. Do you think im tuned a bit lower than i intended? The port is 23 inches long. outside dimensions are 35.5 inches wide, 14 tall, and 30 deep. port is 12.5 x 6 internal . Sub baffle is doubled

More likely you're tuned @ 27-28 and losing a bit of the net volume you think you have. IMO that's simply far too low to tune most subs. You'll wind up with a peak around tuning and a dip up in the 40-50hz range (where actual music happens).

 

[phemps 10+ year member]

More likely you're tuned @ 27-28 and losing a bit of the net volume you think you have. IMO that's simply far too low to tune most subs. You'll wind up with a peak around tuning and a dip up in the 40-50hz range (where actual music happens).

when i first started playing i was concerned it may have ended up lower than i thought but i definitely didnt suspect that much lower. Even if i cut the port back in this configuration, wouldnt the correction factors continue to extend the effective port length near all the way down that side? what would be a good way to help eliminate this go with a port in the center? i have never been quite sure how much to account for correction factors accurately and thought it wouldnt make such a significant difference

 

[phemps 10+ year member]

Also i was thinking i wasn't tuned quite that low because if i set my infrasonic accordingly, shite in the mid-upper 20s seems to even want to unload

 

[hispls 5,000+ posts]

when i first started playing i was concerned it may have ended up lower than i thought but i definitely didnt suspect that much lower. Even if i cut the port back in this configuration, wouldnt the correction factors continue to extend the effective port length near all the way down that side? what would be a good way to help eliminate this go with a port in the center? i have never been quite sure how much to account for correction factors accurately and thought it wouldnt make such a significant difference

I'm pretty certain that the port is behaving like my picture. Tricky when you're running into port length that's close to the length of the side and porting out the side for sure. Running a port down the center may put you in about the same place where the back side is too close to the back wall. Personally I'd make it much shorter and deal with high tuning, or narrow the port width to compensate with some inserts.

Also i was thinking i wasn't tuned quite that low because if i set my infrasonic accordingly, shite in the mid-upper 20s seems to even want to unload

Of course playing mid 20's subs will want to move a lot even at tuning.

 

[phemps 10+ year member]

I'm pretty certain that the port is behaving like my picture. Tricky when you're running into port length that's close to the length of the side and porting out the side for sure. Running a port down the center may put you in about the same place where the back side is too close to the back wall. Personally I'd make it much shorter and deal with high tuning, or narrow the port width to compensate with some inserts.
hmm i dont want to tune too high if its going to affect my low end a lot. In this situation wouldnt decreasing port area actually lower my tuning more? The other problem with cutting down the port is the volume changing as well and theres only so much i can do with the box already constructed. It seems as if the only easy way to go about it would be to build with the port external to some degree, but id really like to try and salvage this enclosure if possible. Thanks for your input

 

[brian84corvette 10+ year member]

if you can get in that box with a saw zaw and carefully cut away 6" of the port wall leingth - you could add 5 or 6 inches of external port to the outside with out too much trouble ? if you still have strange tuning on this box you could fabricate a loading baffle like i did on my ghetto blaster / loud for cheap build log.

my port was unloading like crazy before i built the baffle / loading wall in front of the port to force the subs to use all of the internal air space in my crappy box design

 

[phemps 10+ year member]

if you can get in that box with a saw zaw and carefully cut away 6" of the port wall leingth - you could add 5 or 6 inches of external port to the outside with out too much trouble ? if you still have strange tuning on this box you could fabricate a loading baffle like i did on my ghetto blaster / loud for cheap build log.my port was unloading like crazy before i built the baffle / loading wall in front of the port to force the subs to use all of the internal air space in my crappy box design

I think this may have to be what i try. I may try and trim a bit at a time and see how it reacts and then add externally. Personally id prefer not to go external at all though:crap:

 

[hispls 5,000+ posts]

hmm i dont want to tune too high if its going to affect my low end a lot. In this situation wouldnt decreasing port area actually lower my tuning more? The other problem with cutting down the port is the volume changing as well and theres only so much i can do with the box already constructed. It seems as if the only easy way to go about it would be to build with the port external to some degree, but id really like to try and salvage this enclosure if possible. Thanks for your input

My point was to shorten up the port so that it's behaving more predictable, then if you think you're tuned too high narrow the port opening to tune down. You're sacrificing some port area to low tune at that point but as I see it it's your best bet to dial in the tuning you're after.

Not sure what your definition of "music" is, but I find it difficult to find 35hz and down material on anything that is played at normal speed and not a bass test CD. I think that slowed down music is some of the most obnoxious **** on the planet, seriously, to the people who pretend to like that, is that what you put in your iPod and listen to when you're out for a walk or whatever?

 

[NASTY08IMPALA 5,000+ posts]

My point was to shorten up the port so that it's behaving more predictable, then if you think you're tuned too high narrow the port opening to tune down. You're sacrificing some port area to low tune at that point but as I see it it's your best bet to dial in the tuning you're after.
Not sure what your definition of "music" is, but I find it difficult to find 35hz and down material on anything that is played at normal speed and not a bass test CD. I think that slowed down music is some of the most obnoxious **** on the planet, seriously, to the people who pretend to like that, is that what you put in your iPod and listen to when you're out for a walk or whatever?

Exactly except for a few decaf songs i demo for ppl to show the lower end that stuff is crapp..get ur tuning mid to upper 30s and u will still be able to extend into the mid 20s fine.id try sacrificing the tuning first then port area 2nd

 

[T3mpest 10+ year member]

Bracing seems a little shoddy.. Not sure how long those panels are but I'd look into some panel bracing.. It'll also cut some airspace down and if you are getting any flex or coloration noises right now that could be why it sounds sloppy. It'll also up your tuning, so it's not a bad thing in any case possibly. If you want to know where your tuned, grab some test tones, make sure they are all the same recorded volume. Play each one at a moderate HU volume and wantch the cone move, your minimum cone movement point is your tuning.. When the trunk closes it also extends your port length if your within a port width of the trunk lid... Sometimes you NEED to be that close for the best loading and SPL though.

So basically use my ghetto test to find your boxes tuning.. Realize if your within 6 inches of you trunk in car it's a few hz lower than that.. That'll give you a good idea where to go from there. This stuff is all pretty simple I know, but sometimes car audio 101 type of stuff ends up being the problem, more often than not to be honest.

 

[phemps 10+ year member]

My point was to shorten up the port so that it's behaving more predictable, then if you think you're tuned too high narrow the port opening to tune down. You're sacrificing some port area to low tune at that point but as I see it it's your best bet to dial in the tuning you're after.
Not sure what your definition of "music" is, but I find it difficult to find 35hz and down material on anything that is played at normal speed and not a bass test CD. I think that slowed down music is some of the most obnoxious **** on the planet, seriously, to the people who pretend to like that, is that what you put in your iPod and listen to when you're out for a walk or whatever?

Yea really the only reason i play stuff that extends below that range is mostly for demos and i enjoy feeling the lows and moving air as well. Definitely not something i would listen to on a normal basis just cool to be able to play sometimes. It seems this is my best option at this point, other than starting from scratch which i may end up doing if this doesnt work out anyway. If i double the power im assuming im gonna be too big box wise anyway, this time i may try an adjustable aeroport too although ive always prefered having slots that arent external at all. It seems kind of hard to make a large flared tube sticking out of a box look decent in my opinion

 

[phemps 10+ year member]

Bracing seems a little shoddy.. Not sure how long those panels are but I'd look into some panel bracing.. It'll also cut some airspace down and if you are getting any flex or coloration noises right now that could be why it sounds sloppy. It'll also up your tuning, so it's not a bad thing in any case possibly. If you want to know where your tuned, grab some test tones, make sure they are all the same recorded volume. Play each one at a moderate HU volume and wantch the cone move, your minimum cone movement point is your tuning.. When the trunk closes it also extends your port length if your within a port width of the trunk lid... Sometimes you NEED to be that close for the best loading and SPL though.
So basically use my ghetto test to find your boxes tuning.. Realize if your within 6 inches of you trunk in car it's a few hz lower than that.. That'll give you a good idea where to go from there. This stuff is all pretty simple I know, but sometimes car audio 101 type of stuff ends up being the problem, more often than not to be honest.

Yes i admit i could have taken more time to work on better bracing. From what i can tell the box doesnt have any flex at all but i did think about it resonating enough to be coloring the sound. there's a sound on mostly the transient hits that sounds like that sort of popping sound you hear with heavy clipping when im playing a clean signal near full tilt and i cant quite figure out why. It doesnt sound to me like it could be the box making the noise. Unfortunately its gonna be near impossible for me to do some real good bracing inside without maybe cutting off the top baffle, which i, thinking i may be able to get away with, ive done it on another box before that i needed to change a bit for a temporary setup. then i could alter my tuning a little easier as well