Sub bottoming out or box issue?

[Digital Designs 10+ year member]

Ok, heres the story. I have a 15 inch DC level 4 with level 5 coils. I built my own box. It is around 3.3 cubes tuned to 32hz. The box is built for sub up, port back. The slot port goes across the bottom of the box all the way from one side to the other. Now, I used my DMM to set the gains so my ap15001d is sending the sub like 1200 RMS or so using Decafs test tone for amp setting. Well, the sub sounds awesome from the front of my car, but if you are back by the sub(2008 mazda 3 hatch...) it has a really loud almost slapping noise or something. It is hard to explain. It just sounds like plastic hitting plastic. The sub gets a TINY bit warmer in the center, but my old FI BL got a lot hotter off of around the same power and I never had an issue, I think it is a normal warmth if that makes sense. Anyways, the reason I am thinking it could be the box, is because when I planned it out, I didnt think about the port opening in the box being underneath the sub. It is also hard to explain, but if you look through the cutout for the sub from the top, you can see into the port opening a little bit(about 1/2 inch at most) Is this the reason for the slapping noise? Or could my sub be bottoming out? It does it from about 20 volume up to 26 volume(where I have the gains set for...) and it obviously gets gradually worse as the volume goes up. I know this is super long but I am stumped...

Click to read more...

 

[Louisiana_CRX 5,000+ posts]

set your crossover and subsonic filter properly

 

[Digital Designs 10+ year member]

set your crossover and subsonic filter properly

It is set just how I had it with my BL and my BL was fine. I think the only reason it would be bottoming out is because of too much power, not from playing below tuning. I can play songs with higher notes, and it still sounds like that.

 

[NoPh33rRaCiNg 10+ year member]

set your crossover and subsonic filter properly

x2. had same issue with my lvl 4's w/lvl 5 coils.

 

[Digital Designs 10+ year member]

x2. had same issue with my lvl 4's w/lvl 5 coils.

So why is it doing it? Isnt subsonic so it doesnt play too low? I mean, just about any song I play makes the sound...

 

[Louisiana_CRX 5,000+ posts]

you may be using two crossovers...the decks and the amps...you need to only use one...set your lowpass about 80hz...subsonic about 25hz

 

[Digital Designs 10+ year member]

I am sorry to argue, but I dont see how setting these differently will get rid of the slapping noise I am getting //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif I guess I just gotta try it tomorrow to see..

 

[Louisiana_CRX 5,000+ posts]

let us know if it works...what deck you running ?

 

[Digital Designs 10+ year member]

Same thing you were trying to sell me lol, Kenwood DDX512. I think I might have the crossover set on the deck too, not sure. I still dont understand how these settings are making my sub make this noise

 

[Louisiana_CRX 5,000+ posts]

set the crossover on deck on through...then just use the amps crossovers...you'll still have your sub level adjustments from the deck //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Digital Designs 10+ year member]

set the crossover on deck on through...then just use the amps crossovers...you'll still have your sub level adjustments from the deck //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

But you dont think my sub is bottoming out? Or my box is made wrong?

 

[chillin 10+ year member]

maybe its tinsel slap. Not sure if the dc's have this problem or not, but i know some subs do

 

[Digital Designs 10+ year member]

maybe its tinsel slap. Not sure if the dc's have this problem or not, but i know some subs do

It could be, I have never heard a sub with tinsel slap so it easily could be. But it looked like there was basically like a piece of carpet attached to the bottom of the cone, which I am assuming is to prevent tinsel slap?

 

[VWBobby 10+ year member]

meh, its a DC....its going to sound like S--- while getting loud. Everyone that I've heard is very loud as F--- but it has this Twannnnng that I can't explain.... I agree, start with the simple stuff like tuning. Then start trying to determine if the sound is coming from the sub itself (physical/mechanical flaw) or if the box is having some type of harmonic/loose panel or etc. Sometimes a baffle, or some part can break loose and start flapping in the breeze. I don't think speaker wires can do this, but you never know...especially if its on a tone, compared to music.

 

[TT2ENT 10+ year member]

I believe one of my Memphis subs makes noise ur talking about. Kinda like a tap on excursion. I think it was because the old box it was in had a leak. Just that one sub does it and you can only hear it if I flip my box over (downfire box)