my subs sound like poo

[shaaaboobles 0]

I have 2 fi ssd 12's, they sound good on the high notes but not great, then when the low notes hit they sound even worse, they dont sound terrible, but I know they dont sound any where as good as they should, any help?

And when I set my gain with my dmm, I have to turn it all the way up to even get within two numbers of what its supposed to be,

Any help would be very appreciated

[altoncustomtech 773]

Sounds like you need help all the way around. Give us more info, what HU, what amp, what electrical, what's the specs on the enclosure? The more info you give us, the easier it will be to help you out.

[ssh 924]

What type of enclosure? Ported? if so whats it tuned at. sealed? whats the volume of it? etc

If you expect help then you need to give us more information then "it sounds bad"...

Hows your amp setup? wheres the lpf,ssf set at?

Whats your voltage at full tilt?

Are you using bass boost functions in headunit, eq, etc...

Edited July 11, 2010 by stefanhinote

[shaaaboobles 0]

My box is 37.5w x 21h x 15d tuned to 33hz with a port of 5.25w x 13 h x 25.75 long, on a saz-1500d wired to one ohm, no bass Boost, shitty Jensen head unit, stock electrical with an upgraded ground on battery but the voltage doesn't drop below 12.5

Edited July 11, 2010 by shaaaboobles

[altoncustomtech 773]

The tuning on the box seems WAY off, but I'm still calculating it.....

Are you POSITIVE the subs are wired in phase with each other and the voice coils on both subs are in phase? Chances are that you're having a difficult time setting the gains with a DMM because the output voltage on that Jensen unit is probably very low, but that shouldn't cause the problems you're experiencing. It really seems like another problem.

[shaaaboobles 0]

ya im positive my subs are wired right, but my port is on the side of my box and one of my subs is like right at the opening of the port, and ive heard of unloading because of that but im not sure what that means, and I calculated my port on the12volt.com but I might have done something wrong

[Kanaworm$ 292]

Make sure the RCA's are going to the inputs on the amplifier and not the BR in and BR out. Also I would double check your wiring on your subwoofers.

[cobra93 47]

If those are outside dimensions and 3/4" material, it looks like a 38 hertz tune.

What tuning were you looking for?

Edited July 11, 2010 by cobra93

[bassahaulic 155]

Sounds like it might be the radio.

[altoncustomtech 773]

If those are outside dimensions and 3/4" material, it looks like a 38 hertz tune.

What tuning were you looking for?

That's about what I was coming up with. Another question, is the box perfectly sealed up, no air leaks? Air leaks in a ported enclosure can ruin the function of the enclosure VERY quickly.

[shaaaboobles 0]

ya its all sealed up with silicone, next question, when you calculate the port do you put the net volume before or after the port displacement

[altoncustomtech 773]

I don't think you can add the port displacement to the calculation, you have no idea what the displacement will be until you know all 3 dimensions of the port. You have to use the target volume when calculating.

[shaaaboobles 0]

Well im a box designing so if someone could help me figure out port dimensions for a 33 hz tune on those box demensions that would be awosme

[altoncustomtech 773]

From the quick calculations I had done It looks like you'd need about another 8" of port length to get the 33hz tune. Not something that can be easily performed on an existing enclosure, it would also reduce the internal volume to about the minimum specs Fi recommends for the those subs.

DON'T quote me on that 8" either, that's just punching a few fast #'s in, to be dead on it would require much more precise figuring.

[shaaaboobles 0]

I can always make the box a little bigger, but would that help how my subs sound enough to be noticable

[altoncustomtech 773]

EVERYTHING effects the response of the subs. The problems you're having though I still don't feel that the enclosure's higher tuning is fully to blame. I'd still like to know that you've double checked all the wiring on the subs and tested them with a small battery to verify they're both moving and moving in the same direction. If that's truly kosher then we should probably look at other potential problems, I say this because just having a box tuned to 38hz instead of 33 shouldn't make the sound absolute crap unless you were already used to a very good low tuned setup before this and are comparing the two, just MHO.

[shaaaboobles 0]

Ill re-check them tonight after dinner, but the whole thing about the subwoofer "unloading" because how the port is placed I think could be one of my problems

[altoncustomtech 773]

It could be, but I don't think port unloading affects the sound through the entire played frequency range and generally causes problems like one sub to move further than the other and other weird happenings and then usually only under high power. Now that begs the question, are you noticing the bad sound at high volumes only or at any volume level? Are you seeing the subs moving in any other fashion than in unison?

Someone with better knowledge of port unloading should chime in here, I'm limited in my experience and knowledge of the problem, though I was always under the notion that it isn't really a problem for most daily drivers.

[shaaaboobles 0]

it sounds clean when its not turned up, but when i turn it up it loses its "tight" hitting sound and I cant see the subs because their right behind my seat

[aimone 4]

man i've dealt with this problem a few times with my system and my cousins that i maintain for her. i wouldnt blame it all on the box tuning but that does add to it. im betting its your head unit considering most jensens are crap and dont have sub outputs. it took me 6 months to convince my cousin hers sounded shitty because the dual head unit she had. it had no sub outs so u couldnt control the sub level or filters. once it got stolen and i helped her pick a new one i made sure it had sub outs and it made the subs sound 10x better.

also its taken me 3 tries so far to get my box tuned right. i think im still a smidgen off but as close 33hz as of yet. and i just got my saz1500 like a month ago and im still trying to get it adjusted right the ssf and the lpf are sensitive.

[shaaaboobles 0]

ya I already have the pos for sale lol, Im gonna try to build another box and at least see if it sounds better then, and Im going to recheck my wiring

[Duran 387]

I had a Jensen unit before it was stolen, it was nice. I loved that damn thing.

[Bob345 39]

I am very supprised that noone has mentioned his electrical. Stock electric with a sax 1500?!? I almost garantee that is the problem. You probably have a huge voltage drop. Did you do the big three? 1/0 awg powerwire? If you dident, I highly recomend you do

[aimone 4]

i've got a saz1500 too on stock electrical with 4ga big 3 along with stock and my single fosgate power hx2 15 sonuds great. 12.2 is as low as it drops at full tilt but also my alt and battery are only a few months old and it wont charge any higher than 13.0 anymore but i dont know how accurate my volt meter is, because my screen on my pioneer deh-p680mp busted so i cant use the voltage meter on it and it always ran a little higher then the one i use now just cant remember how much

p.s. im adding a second stock alt and a boat battery soon

Edited July 12, 2010 by aimone

[KU40 173]

Are the subs unloading? Is that the terrible sound you are hearing? It will be sort of a hollow, farty sound, coupled with the subs moving a lot. Is a subsonic filter on the amp set? Where is the highpass filter set? Any crossovers on the head unit? What outputs for the RCAs are you using on the head unit?

Going from 38 to 33 hz would definitely be noticeable. and having the sub close to the port is not the issue.

You say the subs are right behind the seat, do they hit the back of the seats?