sa12, two or four ohm?

[Alan1986]

Hey what's up guys? New to the forums but have been browsing for a while trying to gain as much knowledge as possible.

Anyway I have a question and will try to provide enough info while also keeping it short.

I just recently purchased a hifonics brx 2400 with the intention of running 2 sa12s (currently I only have one in a prefab box) in a custom box. Well the brand new amp wouldn't put out any sound so I sent it back to have it replaced so a friend let me borrow his jl 500 amp. I had my sa12 out of the box and put my dmm on each coil and they both read 3.1 give or take and my friend said to wire it in parallel and if his amp went into protect that would mean I did in fact have a 2 ohm sub as I ordered from woofrsect bc he said his Jul is not 1 ohm stable. the box it's self says it's a 2 ohm. Well after listening to bassnector for 20 minutes straight on the way home I felt the amp and it wasn't the least bit warm, like not at all. so did I get a 2 or 4 ohm sub? Batteries in my meter may be a little old but that to would also mean I have a 4 ohm sub. emailed sundown 2 days ago with no response. Any help will be greatly appreciated.

Edit, post is probably jumbled up bc of I'm dealing with multiple kids at the moment lol.

Click to read more...

 

[cfox10 10+ year member]

Hey what's up guys? New to the forums but have been browsing for a while trying to gain as much knowledge as possible. Anyway I have a question and will try to provide enough info while also keeping it short.

I just recently purchased a hifonics brx 2400 with the intention of running 2 sa12s (currently I only have one in a prefab box) in a custom box. Well the brand new amp wouldn't put out any sound so I sent it back to have it replaced so a friend let me borrow his jl 500 amp. I had my sa12 out of the box and put my dmm on each coil and they both read 3.1 give or take and my friend said to wire it in parallel and if his amp went into protect that would mean I did in fact have a 2 ohm sub as I ordered from woofrsect bc he said his Jul is not 1 ohm stable. the box it's self says it's a 2 ohm. Well after listening to bassnector for 20 minutes straight on the way home I felt the amp and it wasn't the least bit warm, like not at all. so did I get a 2 or 4 ohm sub? Batteries in my meter may be a little old but that to would also mean I have a 4 ohm sub. emailed sundown 2 days ago with no response. Any help will be greatly appreciated.

Touch your multimeter leads together... what does it read? That's how far off your meter is.

Seeing as it's sitting at 3.1, a lot of meters can be off by .9 or more in some cases. I'd just check it and see.

 

[adulbrich 5,000+ posts]

If each coil is reading 3.1 ohms, it's probably a "dual 4" coil sub. Actual DC resistance of the coil is usually a little less than what it's advertized to be, unless it is a "true dual 4 ohm" or something like that.

I know Incriminator gives lots of coil options like "true" resistance coils that are exactly what they say. otherwise, dual 1's usually read .7 and dual 2's usually read 1.4 on each coil.

Depends on the sub and the manufacturer though.

EDIT: Yes, DMM leads have resistance. Completely slipped my mind. Probably is a dual 2

 

[Alan1986]

Thank you both for the quick replies. I left my meter at work today so I'll run back up there tomorrow and get it and see what it says with the leads touching together. But if it is a 2 ohm then shouldn't it put that non 1 ohm stable jl amp in protect. Especially heavy bass music for 20 minutes straight. I've been listening to bassnector and scillrex back and for to work every day 20 plus minutes straight and that amp never gets remotely warm. I could care less what ohm it is just want to know which sub to order next week and what sundown amp I'm going to get.

 

[Alan1986]

Just all the research I've seen in testing voice coil impedance the always show something real close to the specified resistance, mine on the other hand is showing in the middle lol.

 

[adulbrich 5,000+ posts]

Impedance rise may be keeping you in the safe zone, but it's impossible to know unless you do a frequency sweep that Hispls is always talking about, so I won't say anything more on the subject.

 

[A_Contraptions]

also make sure the dmm batteries are good. some meters go wonk when there low

 

[DaytonLax14 10+ year member]

What does the meter read when you connect it to the terminals on the actual box? Do that and let us know.

I've had both dual 2 ohm SA12s and dual 4 ohm SA12s....

The dual 4 read 3.7ohms

The dual 2 read 1.8 ohms

 

[Umbra]

Replace the battery and remove corrosion from the probes by rubbing them down with steel wool, or a light sandpaper. See if that gets you closer to 2 or 4.

Also, like cfox suggested compensate for the resistance in you probes by touching them together and then subtracting that number you get from your measurement.

My guess is that it's a 4 and the meter's off.

 

[Alan1986]

Impedance rise may be keeping you in the safe zone, but it's impossible to know unless you do a frequency sweep that Hispls is always talking about, so I won't say anything more on the subject.

Who is Hispls?

 

[Alan1986]

What does the meter read when you connect it to the terminals on the actual box? Do that and let us know.
I've had both dual 2 ohm SA12s and dual 4 ohm SA12s....

The dual 4 read 3.7ohms

The dual 2 read 1.8 ohms

Ok thanks, I'll do that first thing tomorrow!

 

[Alan1986]

Replace the battery and remove corrosion from the probes by rubbing them down with steel wool, or a light sandpaper. See if that gets you closer to 2 or 4.
Also, like cfox suggested compensate for the resistance in you probes by touching them together and then subtracting that number you get from your measurement.

My guess is that it's a 4 and the meter's off.

Leads are pretty clean visually but I'll do that and post back the results.Thank you.

 

[DaytonLax14 10+ year member]

Ok thanks, I'll do that first thing tomorrow!

I should clarify that the readings I mentioned in my post were not what the dmm was reading when it was connected to the terminals on the box. But by you providing us the dmm readings when it's connected to the box, it will help us narrow down what impedance the sub is wired to, which will help us determine if it's a dual 2 or dual 4.

Try a different multimeters if you or your buddy has one.

 

[Alan1986]

I should clarify that the readings I mentioned in my post were not what the dmm was reading when it was connected to the terminals on the box. But by you providing us the dmm readings when it's connected to the box, it will help us narrow down what impedance the sub is wired to, which will help us determine if it's a dual 2 or dual 4.
Try a different multimeters if you or your buddy has one.

Will do! I'm a tech at a car dealership so I'll try a couple different meters.

 

[adulbrich 5,000+ posts]

Who is Hispls?

Another member on here. We argue.