high note slop

[shackleford]

so recently ive begun to feel as if my box has started falling apart. it almost sounds like an air leak in a sealed box. its not a scratchy coil and its not the hum of my x-over killing a freq. it sounds as if the backpressure in the box becomes excessive above like the mid 40s. i dont know how else to describe it it sound like my subs are fighting to execute the push pull of the highs. this may simply be due to the higher thd of my older amp im currently using. but around and under tuning the box moves air great and sounds smooth as hell even when the notes start to lose there noise as they get farther away from the tuning freq it still has good Power handling and sub control. with no sub sonic ive yet to bottom out and im running a 4-ohm stable amp at 1. but my highs sound like dickcheese any ideas of what might be my problem?could my box rise be fighting my cabin gain? if that even makes since. also my box has visible flex and looks to swell up like an greatly overcharged battery.
ive read my Car peaks at like the low 60s could this have something to do with it the cabin gain causing my pushing of the power envelope to become the envelope opening? i dont think ive done any damage yet and havent been beating on them. but im just worried. also should i cornerload in my hatchback trunk or reflect off of the glass of the hatchback(i drive a 2000 beetle)

[shackleford]

on tcsounds website reading up and i found the perfect word to describe what i believe im eperienceing "compression distortion". too little port area? or box flex?

[SINTORMAN]

Originally Posted by shackleford

on tcsounds website reading up and i found the perfect word to describe what i believe im eperienceing "compression distortion". too little port area? or box flex?

most likely the box if it didn't start out sounding like that. A poorly built box will degrade and weaken over time.

Rebuild the box.

I would do a box that is sub up port back but you can also turn sideways to try sub up port side. Which sometimes works well.

[shackleford]

if i Build my own box which is becoming likely after hearing what the assclowns at the local shops want for a box its going to be a wedge for my hatch so i can maximize my ft^3. im playing around on RE audios box builder but it only allows me to have the port facing towards the wedged side which i dont know how it will affect tuning if it were to be moved to another side. also the box rockford list for my subs does not account for port volume and the min&max ported box volumes are 1.79ft^3? so wtf do i do subtract port area and then aim for that on RE?
did subtract out the port area in rockfords schematic i plan to run over 1k on this box and what ive worked out is about 17in^2/ft^3. whats a good ratio to aim for in that dept? how is the port's physical placement going to affect the perfomance of my subs? any do and donts? also is it ok to corner load my port in the hatch of my beetle? how much space do i need between the port and the surface infront of it? can i run the subs facing up and have my amps on the angled hatch side be cooled by my box's airflow?

[shackleford]

i think the problem im experiencing is really nothing more than dramatic port noise given i only have about 12in^2 port area per ft^3.

[98Civic]

Don't use the calculator on RE's site, it is not accurate. Torres Box Calculator works well. I could be wrong but I don't think your port area is whats causing noise. The box I have now is 10 in^2 per cube on an Obsidian 15 on 1000rms and I have no port noise.

[shackleford]

ok well i dont think the subs are blown..... my air velocity at the port seems a little reckless. i am running a fosgate p601s at 1 ohm currently until my brz1200 comes back from repair. could it be a combination of undersized port and how close i physically am to my box. my head in my car is no more than 4ft from the port. however i must note no one else that gets in my car seems to be able to hear the nois im hearing. it not the subs reaching there mechanical limits as they continue to move more when volume is increased. its not a scratchy coil/s i would be able to feel it, this it what happened to my first subs. the subs looked ok when i rewired my box. so im not sure what it is i seriously think the backpressure in my box is causing air leaks to open up and cause this noise. it doesnt appear until around 30 on my HU my EQ is relatively flat and i never play past 40 on it with the HU peaking in volume at 50.

[shackleford]

Its officially port noise.when its making the noise its moving a crazy amount of air that I'd say is comparable to a few hairdryers running all at once

my freind has http://www.bassslammer.com/products/carpeted/BASSslammerBS212V.pdf and is willing to sell it to me for $20 its a little undersized so id get a little better power handling, but i never got why RF said 1.79cu ft strictly in a ported enclosure especially when they dont event account for port or sub displacement in this reccomendation. but it has much more port area. so my question is do you think 5/8" is going to blow up like mine currently has or is this prefab company somewhat reputable?


EDIT: im buying it its $150 box crutchfield thats been discontinued for the chance of good louder bass for $20 im not going to turn the offer down