wierd subwoofer pop at certain frequencies

[MadAudio 10+ year member]

hi all been having a bit of trouble with my subs ... as the title says at certain frequencies

in the begining everything was fine subs would hit hard as crap. Then one day few weeks ago i was driving around and all of a sudden without changing the volume subs started making this horrible popping noise.So i stopped car checked all the connections i could at the time everything seemed fine but still go past certain volume pop pop pop ... honestly it sounds like something got jarred loose i know it sounds silly but anyways.

i drive car home with music off and start trouble shooting checked ohm load with dmm at the posts and it reads 1 ohm ( havent checked directly on subs yet will do this 2morrow). Rechecked amp gain and and they read 37v wierd cause i had originally set them to 35v so i reset it back to 35v its more bearable but the popping is still there . so i thought maybe something in the electrical system is fooked so i drove car to local parts place had them check charging system and alt is fine but battery was fubar so i i bought a shiny new yellow top ( i know i know but its all i can get where i live ) and no change other than more powerful start ups. other than that they sound great and hit very hard but its driving me nuts

subs are 2 premier spl2000 wired to 1 ohm they are rated @ 750rms each sub ssf@around 36hz any lower and popping noise gets worse

the box is 1.75 cu.ft. per sub ported to 42hz

amp is a nine.1 gain set at 35v=1225w@1ohm

HU is eclipse 8445

when i set the gain for the sub i had non fader output on hu set to +3 but at that level some some songs pop like crazy setting non fad out to 0 gets rid of most of the pop but i lose tons of bass

car alt is 110 amp

also i dont know bout this but i found it a bit wierd that the dmm read 1 ohm exact off the posts none of my other subs have ever measured exact on the ohm load its usually a bit lower or higher but these measured 1 ohm on the nose and i also dont have any headlight dimming anymore where i used to get quite a bit of dimming at night

thanks for any help solving this

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[Moe Lester 10+ year member]

its tuned way too high and you are playing frequencies under tuning and bottoming them out, that is why they are popping...

 

[MadAudio 10+ year member]

the tune # i got from plugging in the specs to winisd not sure if its correct i basically built it to the specs on the premier sheet 1.75cu.ft. ports 4"x6.5" but winisd reported that as 45 hz so i made the ports a bit longer almost 8" which winisd reported as 42 hz but was as big as i could go at the time without using a elbow .. well i might be able to go a bit longer ill try in the morn

but funny how it sounded absolutely fine for like 2 months then all of a sudden pop

if this indeed is the problem what do you suggest i port 2? i think i can go as long as 9.5 inches without using a elbow winisd reports that as 39 hz what do you think?

ohh and thanks for the help

 

[slicks5150 10+ year member]

qouted from mad audio.

i drive car home with music off and start trouble shooting checked ohm load with dmm at the posts and it reads 1 ohm ( havent checked directly on subs yet will do this 2morrow). Rechecked amp gain and and they read 37v wierd cause i had originally set them to 35v so i reset it back to 35v its more bearable but the popping is still there . so i thought maybe something in the electrical system is fooked so i drove car to local parts place had them check charging system and alt is fine but battery was fubar so i i bought a shiny new yellow top ( i know i know but its all i can get where i live ) and no change other than more powerful start ups. other than that they sound great and hit very hard but its driving me nuts

read here for setting gain controls. section 63 on the right hand side of the site.

http://www.bcae1.com/

 

[MadAudio 10+ year member]

SLICKS5150

i set the gains using the tutorial that can be found here http://forums.caraudio.com/vb/showthread.php?t=63933 set the volume to my desired top end 62 out of 90 set the bass output to what i wanted in my case +3 used a 45hz 0db ref sinewave and set the gains to 35v output at 62 volume

1200wrmsx1ohm(sqrt)=34.6v i settled for 35v but for some reason when i rechecked after they starting popping voltage read 37v not 35

so im not sure what your trying to say ...

i was just saying its wierd that i set the gains to 35v and they read 37v as thats a pretty big difference

35x35=1225 watts 37x37=1369 watts

moe lester

i did as u suggested and made port a bit longer now they are 9 inches long and ALOT of the pop is gone so right now im headed outside to cut some pvc longer about 11 inches so that once mounted it will be around 10.5 inches long that should give me a tune of close to 38hz ill let you know how it goes cause im not sure i can make them that long straight

thanks for all the help people

 

[MadAudio 10+ year member]

well just finished cutting and installing new ports 11"x4" winisd reports this as 37 hz as well as ticking off my nieghbor during testing ( i apologized nicely) //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

anyways the pop is still there a little more than before but not as much as orginally but other songs have taken on a new life one song hit so hard it vibrated my head when before the bass was really low on that track at this point im thinking the subs might have gotten damaged although the way most songs hit ( very very hard and clean) make me think its something else....

any ideas?

 

[Slaugh 10+ year member]

is it the same pop you hear in this case?

http://www.cashmoneyuploads.com/view/v123183/

 

[jrz126 10+ year member]

maybe you are running the amp too hard. Do you know for a fact that the amp can do 1200Wrms?

Chances are the amp is over rated and you are pushing it into clipping

 

[JimJ 5,000+ posts]

subs are 2 premier spl2000 wired to 1 ohm they are rated @ 750rms each sub ssf@around 36hz any lower and popping noise gets worse

Biggest line right there.

Moe's right - the drivers are simply unloading under tuning and that lovely noise you hear is the driver bottoming itself out.

 

[MadAudio 10+ year member]

SLAUGH

not really mine really is a POP

jrz126

the amp is a nine.1 rated 1200@1ohm rms

Jack Frost

i have to agree also, like i said in my last post the way they hit hard and clear on some notes makes me think its something in the setup i did wrong so today i retuned down to about 37 hz from my understanding the ssf should be about 5hz below tuning? so at 37hz tune ssf should be about 30-32hz?

i think you and moe have got it right to as what the problem is but what else can i do to fix it?

 

[MadAudio 10+ year member]

bringing the dead back to life

i was never able to get rid of the noise totally, till last week i decided to little by little go over every setting between hu and amp. redid xovers on amp reset ssf pop still there ,xovers on hu etc pop still there ... then just for kicks i decided to mess with the time alignment the 8445 comes with what seem to be preset delay settings for different vehicles and when i first installed system i set it to minivan and left it as thats what im driving so i tried different car types and when i set it to compact all of a sudden the bass returned in a scary boombastic way. my rearview mirror didnt vibrate it dropped! one sec im looking out the back window through the rearview mirror next second im looking at carpet through the rearview mirror . before if i set the non fad output to more than +2 i got the pop now i can take it to +5 at same volume level and its clean as a whistle .

i went to the iserv/audio download eclipse website and when i checked the settings on minivan in time alignment it showed a +3 db in the subwoofer slot . but when set to compact there is +0 db in the subwoofer slot so im guessing that in combination with my not so powerful electrical system were driving the amp into clipping causing the pop.

what do yall think?