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View Full Version : Reduced port area = Happiness :D *pics*



Xprime4
05-29-2009, 10:53 AM
I wasn't fully satisfied with the enclosure i builded two weeks ago. My subs are Aq sd2.5, the old american made model. Box size is 7.5 before subs and port displacement. My old box had a big *** port. Around 18inch/sq per ft/cu

http://i371.photobucket.com/albums/oo152/xprime4/box10.jpg?t=1243607824

I had these subs in approx the same volume with a smaller port area before, and they weren't sounding as great at all. I mean, the bigger port area was definitively louder ... but it was also too peaky. It was tuned to 38hz. From my testing, there was a huge peak around 35-45, which was making it sounds like **** on music. The transition response wasn't that great either and the subs were having hard times doing fast kick drum. It was sounding "boomy" and unclear at every level. I wasn't enjoying my substage so it was pretty much off in the last weeks.

So yesterday, i decide i wasn't going to do another box, but i wanted to cut the port area a little. So i went to Home Depot, bought a 48x48 mdf 3/4 sheet and cut it in the initial port mdf dimension. 20.75x 16 and 15/16 (my height is 17) That way, i could still be able to put those in the port without problems.

http://i371.photobucket.com/albums/oo152/xprime4/HPIM2459.jpg?t=1243608290

So i glued 1.5 thick mdf to the port and put some sillicone in the leftout holes. I put some tape in the inner port and i sanded the corner.


Now i'm happy again :D From my calculs, i'm back to around 12inch/sq per foot/cu with a 33.25hz tuning. The subs are hitting lower, sound shitload better and are definitively a huge step over what it was sounding like few hours priors. Transition response is now great and the subs almost sound as good as the fiQ18 I had few months ago in my car. The Q is still hitting lower, i'm pretty sure the fs is lower.

Cliff:

-Port area affect a lot the sq and the spl. I won't ever go over 12inch/sq per foot/cu in a daily setup.

-If you don't like your box, you might be able (in a slot on at least) to "repair" it.

-I love Spl, but it can ruins music when you're too much spl oriented.

-Audioque subs still play low with high tuning, but they are ALOT flattier and sound shitload better with lower tuning and small port area

Have a nice day, i'll be in my car listening some music under the rain


btw, i might have lost a db or two, but that's not that important since i'm not going to comps... and do you really like your peaky basslines anyway?

mmouse57
05-29-2009, 11:27 AM
I agree those ports sizes on some boxes are redic to big.

if done right you can use a 3in x 8in port on 3 w7 jl 10's and it will never show signs of noise. but some guys do like 5x14, lol just dont see why you wnat such a big port if you can get the smallest size possible to sound just right :)

nice build :)

Xprime4
05-29-2009, 03:14 PM
I agree those ports sizes on some boxes are redic to big.

if done right you can use a 3in x 8in port on 3 w7 jl 10's and it will never show signs of noise. but some guys do like 5x14, lol just dont see why you wnat such a big port if you can get the smallest size possible to sound just right :)

nice build :)

thanks a lot Mmouse57 for caring, it seems like you're the only one :crap:

caraudio'er are only interrested in number on tl....

mlstrass
05-29-2009, 03:18 PM
if those are 15's then your box size is way too small. That would cause the lack of bottom end and peaky response. I've used boxes tuned to 42Hz with 18-20^2 per cube of port area with no problems at all.

My current set up is tuned to 40Hz with 18^2 of port and it sounds very good on rock, jazz, blues, metal, etc...

Xprime4
05-29-2009, 03:24 PM
well the lows always been there, even if the box is a bit on the small side. The bass was just too muddy for me with a such huge port area. Maybe it would have been better if i had 4ft-4.5ft net per sub, but space is kinda of an issue... look at my sign

Aq subs are kinda versatile (sp???) they can go loud and low even when tuned high, but they can give extremly detailed sound when tuned low with smaller port area. With my old port, they just didn't have the punchiness aq subs are know for...

WOT
05-29-2009, 03:26 PM
They sound like **** with little port area

Im literally building a new box for my sdc 2.5 15's this second (came in to eat a freezie) and going with over 100sq in of more port than the last box

And i guarantee its gonna sound better. I think I will be around 17sq in / cube @ 38

mlstrass
05-29-2009, 03:57 PM
Bigger enclosure would help a ton, but if you don't have room nothing you can do. I did a wall last year with 4 15's in 12cubes and it was decent, but nothing like the new set up.

To get rid of the muddy bass cutting the EQ at 31.5/50Hz can work wonders. My SQ set up has those settings at -2 to -4 and there is NO boomy sound or exaggerated bass at all. I listen to everything but new rap, so that's how I listen 99% of the time...

oxsign
05-29-2009, 04:02 PM
Sorry to jack your thread, but i do have aquestion regarding this exact thing.

Is the amount of sq" of port per cube done gross or net?

I'm getting ready to build a box that is 5 cubes (net) with 65sq" of port tuned to 43Hz. I'm going a little more for daily SQ, but I would like it to get loud too.

P.S. It's for 3 sound splinter 12"s.

Xprime4
05-29-2009, 04:04 PM
They sound like **** with little port area

Im literally building a new box for my sdc 2.5 15's this second (came in to eat a freezie) and going with over 100sq in of more port than the last box

And i guarantee its gonna sound better. I think I will be around 17sq in / cube @ 38

what ratio port area/box vol did your last box was? it looked pretty small from the picture i remember

also, i don't have enough equalizing band to get down to 31hz. I did test with some fast kick drum bassline and it's now 10x sharper with the 12in/sq vs 18in/sq... at least with my box volume

mlstrass
05-29-2009, 04:06 PM
Port area is for NET volume of the enclosure...

shellfish
05-29-2009, 04:54 PM
bigger port=louder
smaller port=better sq
Is that right? As far as i remember everyone here always rants about huge ports...

Xprime4
05-29-2009, 05:42 PM
bigger port=louder
smaller port=better sq
Is that right? As far as i remember everyone here always rants about huge ports...

From my experience, it works like this. But then, at higher level, if your port ain't big enough, you'll experiment port noise. Bigger port area usually = peakier @ the box tuning freq.

Spl'er just don't give a **** about how it sounds...