OHM issues and impedence matching transfoermers

[herbykw 10+ year member]

I have two coils parallel to one channel of the amp. The cone moves in and out, with a slight clicking noise. from outside i can not see anything in the way or that should make noise.

Looks like someone had repaired one or more voice coils, one of the four terminals were brass and the other 3 are chorme

Oddly, the brass terminal is the only one that i got a reading even close to advertised. Before i moved the wires it read 1.5 ohms. two of the other terminals would not read anything, and one read 4ohms, then i moved the cone, and now i can not get any reading on it either.

am i using the meter right? i never have done this before.

 

[herbykw 10+ year member]

I dont know the exact model number of the sub. I know its a MA Audio 15" hard kore quad voice coil 1.5 ohm and rated at 5000w rms and 10,000w peak. Thats about it. I bought it used.

 

[mil81 10+ year member]

Yeah dude, both your voice coils should be reading the same. The fact that one went from 4 ohms to non readable, is quite suspect. Also, if you push the cone down straight, you shouldn't be hearing any sounds, like the clicking you were explaining.

It doesn't sound to me like you had anything wrong with the wiring, so I don't think it was anything you did that hurt the speaker.

You do have some misunderstandings about what Impedence, and "Ohms levels" mean though. Impedence, or Ohms, in this case is basically a measurement of resistance. The less the resistance (Ohm reading), the more power can flow through. So having the speakers in a lower impedence level, is actually more risky than having a higher level.

I hope that made sense.

 

[Zakerid 10+ year member]

1.5/1.5= around 1.
1.5/1.5/1.5/1.5= below .5

you Fail at OHMs law

 

[lilmaniac2 5,000+ posts]

no you don't need an impedence matching transformer, they are made specifically for spl cars

 

[mil81 10+ year member]

you Fail at OHMs law

LOL. That is funny.

 

[audioatg 10+ year member]

Your approximation of 1.5 being around 1 is quite a big difference, especially being that DCR is almost always below nominal impedance. In your case a 2 ohm nominal sub is quite different than a 1 ohm nominal.
Either way I fail to see where he is paralleling all coils to a single channel?

You know your right. But Im just guessing at what hes doing just like everyone else is. He hasent been on to tell us more about it. Looks to way I have read it hes running it two channel. Two coils per channel. I have a APX quad coil .7....I run it series then parallel.

 

[audioatg 10+ year member]

you Fail at OHMs law

Actually No I dont. but you keep thinking that.

 

[lilmaniac2 5,000+ posts]

Actually No I dont. but you keep thinking that.

actually yes you do, when wiring multiple things in parallel with the same impedence you dont divide it by itself, you divide it by the number of items in the circuit

2/2/2/2 = 1 just as 1/1 is = 1

so yes you do

 

[DidUHearThat? 10+ year member]

Sounds like the sub was damaged and repaired before you bought it and may not have been working properly or was damaged again after the repair.

That is a draw back of having so many voice coils, too many parts to have fail.

I would find a new sub to go with that amp.

 

[ultimate157 5,000+ posts]

actually yes you do, when wiring multiple things in parallel with the same impedence you dont divide it by itself, you divide it by the number of items in the circuit
2/2/2/2 = 1 just as 1/1 is = 1

so yes you do

He's not dividing, that's his parallel notation (Actual parallel notation is || )

Therefore, 1.5 || 1.5 || 1.5 || 1.5 = 0.375

 

[lilmaniac2 5,000+ posts]

He's not dividing, that's his parallel notation (Actual parallel notation is || )
Therefore, 1.5 || 1.5 || 1.5 || 1.5 = 0.375

so if parallel notation is ||, and he had a slash which normally denotes division, how can you say its parallel notation lol

 

[audioatg 10+ year member]

so if parallel notation is ||, and he had a slash which normally denotes division, how can you say its parallel notation lol

Next time Ill put huge spaces inbetween everything........Back to the subject at hand. So does he know he has blown the sub. So he was wiring two coils per channel...

 

[lilmaniac2 5,000+ posts]

Next time Ill put huge spaces inbetween everything........Back to the subject at hand. So does he know he has blown the sub. So he was wiring two coils per channel...

Sorry for assuming that / meant division, like it is on a calculator.

check your battery in the dmm, if its dying you may get inconsistant readings, although I'm pretty sure the sub is blown

 

[audioatg 10+ year member]

Whats the lowest that amp can handle two channel mode. I kindof find it odd that the sub blew that fast. Unless it already had problems.