sub experts... whats wrong with this sub?

[tcguy85 10+ year member]

http://s111.photobucket.com/albums/n159/cavalier94sq/?action=view&current=MVI_3690.flv

http://s111.photobucket.com/albums/n159/cavalier94sq/?action=view&current=MVI_3687.flv

its a brand new shiva-x. i know it's hard to tell how much excursion is going on but it's not very much. at about 1/2" of excursion it starts making that nasty scratching clicking sound.

BTW, this sub has 27mm of one way xmax. so it's no where near bottoming out. from what i have read, this sub is a bottom less design anyway. all suspension limited.

what do you experts think is wrong with it?

Click to read more...

 

[Canaan 10+ year member]

mis-aligned coil.

 

[Grinder1989 5,000+ posts]

mis-aligned coil.

Or the screws/bolts holding the basket could not have been tightened down correctly.

 

[tcguy85 10+ year member]

mis-aligned coil.

thats what i'm thinking.... anybody else agree.?

very slight pressure on certain parts of the surround will either make the sound get worse, or better.

 

[tcguy85 10+ year member]

Or the screws/bolts holding the basket could not have been tightened down correctly.

the screws holding the motor to the basket?

 

[Ed Lester 10+ year member]

1st, sounds like you are playing frequencies too low for the sub to stay linear and the coil could be hitting the pole piece.

2nd. The coil can be mis aligned and hitting the pole piece

 

[Grinder1989 5,000+ posts]

Yea. The basket is held down by screws....if the screw holes are not perfect or the basket is messed up at the holes or they are not tightened down right, it will mis align the basket causing the coil to rub. It sounds like a manufacturer defect to me.

 

[WildSebring 10+ year member]

thats what i'm thinking.... anybody else agree.?
very slight pressure on certain parts of the surround will either make the sound get worse, or better.

x2 on the misaligned coil..

A guy on here a couple days ago had the same problem with a DLS Ultimate sub....coils tested good but made that funky scratching sound...

Mis-aligned coil is all.. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[tcguy85 10+ year member]

1st, sounds like you are playing frequencies too low for the sub to stay linear and the coil could be hitting the pole piece.
2nd. The coil can be mis aligned and hitting the pole piece

there is no way your 1st choice is possible. this sub has 27mm one way xmax. it should move a hell of a lot farther than 1/2" total w/o any odd noises.

25.4mm = 1 inch.

so this thing has over 2" peak to peak linear excursion. the xmech is 35mm. sp she isn't anywhere near bottoming out, this sub is suspension limited anyway. it won't hit the back plate.

 

[tcguy85 10+ year member]

x2 on the misaligned coil..
A guy on here a couple days ago had the same problem with a DLS Ultimate sub....coils tested good but made that funky scratching sound...

Mis-aligned coil is all.. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

ok thats what i though from the start.

looks like a gotta get a replacement. it's pretty crappy cause the box, the packaging inside the box and the sub itself all look perfect. so it isn't a shipping problem.

what sucks is that it took 9 days to get this thing. i'm gonna have to ask them to 2nd day air me a replacement. i cannot wait another 9-10 days.

 

[Grinder1989 5,000+ posts]

2. Is right. Call the manufacturer and tell them you have a defective sub....problem solved.

 

[Ed Lester 10+ year member]

there is no way your 1st choice is possible. this sub has 27mm one way xmax. it should move a hell of a lot farther than 1/2" total w/o any odd noises.
25.4mm = 1 inch.

so this thing has over 2" peak to peak linear excursion. the xmech is 35mm. sp she isn't anywhere near bottoming out, this sub is suspension limited anyway. it won't hit the back plate.

It has nothing to do with Xmax and bottoming out.

It has to do with non linear movement.

I have seen it many times before when frequencies that were too low were played, especially with subs with no acoustical suspension i.e. no enclosure. Or a ported enclosure where the F3 was above the frequency being played.

Can I ask what frequency was being played?

 

[tcguy85 10+ year member]

It has nothing to do with Xmax and bottoming out.
It has to do with non linear movement.

I have seen it many times before when frequencies that were too low were played, especially with subs with no acoustical suspension i.e. no enclosure. Or a ported enclosure where the F3 was above the frequency being played.

Can I ask what frequency was being played?

i don't remember which frequency i was playing in which videos. it doesn't matter anyway, the cone was only moving a half an inch tops. and if i put just a tiny bit of pressure on certain spots of the surround the noise would go away, other spots it would worsen.

i first noticed the sound when i was playing pink noise and using my rta to set phase and t/a. i can't stand loud pink noise, so it doesn't take much to get it to make the sound.

i kinda figured it was a misaligned coil but just wanted some other opinions before i call them tomorrow and tell them thats what is wrong. in all my years of audio this is the first problem have had with a defective item. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[Ed Lester 10+ year member]

i don't remember which frequency i was playing in which videos. it doesn't matter anyway, the cone was only moving a half an inch tops. and if i put just a tiny bit of pressure on certain spots of the surround the noise would go away, other spots it would worsen.
i first noticed the sound when i was playing pink noise and using my rta to set phase and t/a. i can't stand loud pink noise, so it doesn't take much to get it to make the sound.

i kinda figured it was a misaligned coil but just wanted some other opinions before i call them tomorrow and tell them thats what is wrong. in all my years of audio this is the first problem have had with a defective item. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

I have seen misalighnment problems before too.

They will just recone it or send you recone parts. Should be easy enough.

 

[muskyhunter567 10+ year member]

i dropped a midbass once and it sounded like what yours is sounding like, the magnet was a little off set from the basket, and you could hear the coil kinda rubbing a little bit when you would push in it just right, banged on it a little bit and got it lined up again and she worked great, good old radioshack speakers, and sorry to thread jack but whats an rta and how do you set phase? and whats t/a? i just wanna know the phase thing cause ive got two L7s and they dont move in sync with eachother and it bothers me, good luck with the sub though