odd resistance

[jonbearsmt 919]

ok i have 2 nightshade V2 D1s and as far as i can remember my coils always sat at pretty much even 1 with a variance of .1 or so ...

so in series they would be at 2 ohms per sub... then of course paralleled to 1 ohm at the amp ...

well today i was out testing some new songs.. and my subs never get hot .. but today i heated them.. and when i was done playing i checked my temperature of the dust caps and they were both pretty hot.. 1 being hotter then the other... no problem the shades are beast they can take a little heat...

so after that i went to the store, then on the way home i played my stereo again .. but it was not as loud... first thought shit.. i burned a coil ..

so i came home. pop the trunk grabbed the DMM.. and heres what i found.

2 ohms at the amp.. where it should be 1

i un hooked the subs from the amp and DMMEd each sub should have been 2 ohm.. but it was at 3 ohms each side.

i know that the impedance of the sub should be a dual 1.. but most often the resistance is higher... i know this... and 1.5 on each coil would make 3 ohms persub.. and leave me with a final load of 2 ohms... but like i said ... i remember my subs metering out 1.ohm.

its alot of work for me to pull the box and subs to check each coil. but im going to do it soon.

any ideas guys?

[stevemead08 752]

.7 per coil, 1.4-1.5 each sub

[stevemead08 752]

did you pull em out yet?

[stevemead08 752]

did you pull em out yet?

[ricksi30 923]

Agreed D1's usually read ~ .7

Hopefully it's just a disconnected wire somewhere.

[KyleBrown 121]

Agreed D1's usually read ~ .7

Hopefully it's just a disconnected wire somewhere.

this

[jonbearsmt 919]

Agreed D1's usually read ~ .7

Hopefully it's just a disconnected wire somewhere.

i dont see how.

[ricksi30 923]

Agreed D1's usually read ~ .7

Hopefully it's just a disconnected wire somewhere.

i dont see how.

How do you have the wires coming out of the enclosure? I would inspect everything on the exterior, if nothing seems off you'll have to pull them.

[jonbearsmt 919]

if one of the wires on the side of the box would have come off then the sub would not meter at all.. as each sub is in series.

[Quentin Jarrell 671]

Did you let them cool and re measure.

[jonbearsmt 919]

Did you let them cool and re measure.

just did that....and tried a different dmm....same shit

[Impious 1,476]

Did you let them cool and re measure.

Was going to be my question.

Resistance will increase if the coil is hot.

[Impious 1,476]

Did you let them cool and re measure.

just did that....and tried a different dmm....same shit

Missed this post when I replied.

You're going to have to pull them out & measure the coils.

[Tirefryr 1,742]

Always measure at the coil since the wire and it's connection will add resistance. Shouldn't be much, but there are instances where a connection can be an issue.

[jcarter1885 995]

Did you let them cool and re measure.

Was going to be my question.

Resistance will increase if the coil is hot.

Same thing I was thinking, heat will change resistance.

[jonbearsmt 919]

like i said,. they are cold. i dont see the short run of wire i have causing a 1 full ohm ..... ill pull the subs when i get a chance....

[sundownz 197]

Touch your DMM leads together and see what it says.

If the coils were "half broken" then resistance on one side would double as they are bifilar wound coils -- a D2 is actually Quad-4 for example. Then two 4 ohm windings are in parallel per side for 2 ohms.

[jonbearsmt 919]

Touch your DMM leads together and see what it says.

If the coils were "half broken" then resistance on one side would double as they are bifilar wound coils -- a D2 is actually Quad-4 for example. Then two 4 ohm windings are in parallel per side for 2 ohms.

so i may have two half broken coils one on each sub... at the same time.?

you know whats funny.... im not even mad at my self... i wanted to pull the box anyway,... and i wanted to recone the subs to dual 2's any how..... i had just NEVER seen this issue before. blew my mind.

Edited April 13, 2012 by bigjon

[sundownz 197]

Touch your DMM leads together and see what it says.

If the coils were "half broken" then resistance on one side would double as they are bifilar wound coils -- a D2 is actually Quad-4 for example. Then two 4 ohm windings are in parallel per side for 2 ohms.

so i may have two half broken coils one on each sub... at the same time.?

you know whats funny.... im not even mad at my self... i wanted to pull the box anyway,... and i wanted to recone the subs to dual 2's any how..... i had just NEVER seen this issue before. blew my mind.

Most likely not -- it would say ~2 ohms more than likely if they were half out.

See the first part of the post; touch the DMM leads together and see what it says first.

[jonbearsmt 919]

Touch your DMM leads together and see what it says.

If the coils were "half broken" then resistance on one side would double as they are bifilar wound coils -- a D2 is actually Quad-4 for example. Then two 4 ohm windings are in parallel per side for 2 ohms.

so i may have two half broken coils one on each sub... at the same time.?

you know whats funny.... im not even mad at my self... i wanted to pull the box anyway,... and i wanted to recone the subs to dual 2's any how..... i had just NEVER seen this issue before. blew my mind.

Most likely not -- it would say ~2 ohms more than likely if they were half out.

See the first part of the post; touch the DMM leads together and see what it says first.

my DMM reading jumps around ALOT.. when i i touch them togather... but it settles at 1. and .9 so 1 ohm i guess.

[edouble101 314]

Your dmm isnt reading correctly

[jonbearsmt 919]

both my DMMS are wrong?

i have alot of speakers laying around here... i just metered them all.... every 4ohm speaker i meter reads 4 ohms.... every 8 ohm speaker 8 ohms every 2 ohm speaker meters 2 ohms.......

go back out to my car... 2 ohms at the amp.

[Quentin Jarrell 671]

Remember 4 ohms is nominal not the a actual resistance. For example a Fi two ohm coil is 1.4 Not sure of the sundowns

Edited April 13, 2012 by Audibel Customs

[edouble101 314]

Resistance across your dmm leads should be zero, no resistance.

Are the batteries in your meter good? Are your dmm leads properly connected to the meter?

Which dmm that you have? How do you have it set?

[16K 159]

did u pull them out of the box and look at them yet ??

sounds like a fried coil to me