2 ohm speakers on a aftermarket deck
10-13-2010, 01:47 PM
#1
0 Watt CAFz'r
Thread Starter
Join Date: Mar 2006
Posts: 9
2 ohm speakers on a aftermarket deck
I was browsing the net today and came across this:
Need help with car speakers - 2 ohms with an aftermarket deck
Ok, here we go...
I have a 97 Prelude with 2 ohm rear speakers. I bought a Pioneer DEH-P4000UB deck today and when the sound gets too loud, the speakers cut in and out. I asked the Circuit City guy about it and he said it's because the speakers are 2 ohms and the deck and/or amp is running on 4 ohms so the speakers are being fed more power than they can handle. I understood this fine and accepted it... until I was looking for aftermarket speakers to replace the old ones.
I came across the JBL GTO927 6"x9" speakers and under the details, I found this little piece of info: 2-ohm impedance for extra power (compatible with all factory or aftermarket car stereos)
If these 2-ohm speakers are compatible with anything, why are mine cutting out? Why do these supply more power than 4-ohm speakers?
Thanks
You'll only get more power out of 2 ohms speakers if they're matched to a 2 ohm output impedence amplifier. When you hook up a 4 ohm amp to 2 ohm speakers you have an impedence mismatch.
Matched Z = max. P transfer.
Now I was under the impression that if you put 2ohm speakers on a aftermarket deck the draw of power would be too great and eventually the aftermarket radio would die. Who is right me or this other guy?
Need help with car speakers - 2 ohms with an aftermarket deck
Ok, here we go...
I have a 97 Prelude with 2 ohm rear speakers. I bought a Pioneer DEH-P4000UB deck today and when the sound gets too loud, the speakers cut in and out. I asked the Circuit City guy about it and he said it's because the speakers are 2 ohms and the deck and/or amp is running on 4 ohms so the speakers are being fed more power than they can handle. I understood this fine and accepted it... until I was looking for aftermarket speakers to replace the old ones.
I came across the JBL GTO927 6"x9" speakers and under the details, I found this little piece of info: 2-ohm impedance for extra power (compatible with all factory or aftermarket car stereos)
If these 2-ohm speakers are compatible with anything, why are mine cutting out? Why do these supply more power than 4-ohm speakers?
Thanks
You'll only get more power out of 2 ohms speakers if they're matched to a 2 ohm output impedence amplifier. When you hook up a 4 ohm amp to 2 ohm speakers you have an impedence mismatch.
Matched Z = max. P transfer.
Now I was under the impression that if you put 2ohm speakers on a aftermarket deck the draw of power would be too great and eventually the aftermarket radio would die. Who is right me or this other guy?
10-13-2010, 02:19 PM
#2
Administrator
Join Date: Feb 2006
Posts: 16,855
The first problem is that the guy appears to be after better sound but is still using deck power. 
If the IC in the deck can't handle the load that 2ohm puts on it then it's only a matter of time before it protects or fails.
If the IC in the deck can't handle the load that 2ohm puts on it then it's only a matter of time before it protects or fails.
10-13-2010, 03:15 PM
#3
Bad idea off of deck power. They work great off amps and the extra power is noticeable, but off a deck's ic, it's just a matter of time before it's cooked. I think the idea was good, but the product guys neglected to think about all those youngsters that would be cranking it most of the time. Maybe they're hoping the deck manufacturers will see the a trend and design decks that are 2 ohm capable.
10-13-2010, 04:50 PM
#7
[QUOTE=Big Pappa;617336]your right... but your oh so wrong for asking help at circuit city, future shop, best buy etc etc.[/QUOTE
You'll be surprised who works at FS, BB etc...on here. Some are world champs or in that category.
You'll be surprised who works at FS, BB etc...on here. Some are world champs or in that category.
10-13-2010, 07:37 PM
#9
500 Watt CAFz'r
Join Date: Oct 2009
Posts: 730
JBL markets 2 ohm speakers that are safe to run on 4 ohm systems due to impedance rise as the coils operate and get hotter. If you try and crank the system right off the hop, the amp inside the deck will shut down to prevent damage and come back on when it "sees" a safe impedance. The idea isn't to simply punch the volume when the coils are "cold" as they rest at roughly 2 ohm (creates a rise in power in the voltage rails inside the head's amp that they can't carry). The closer you are to 0 ohm, the closer you are to a short circuit, so if the amp's voltage rails can't safely deliver the new power level you'll have issues like this.
