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Running 2 ohm JBL coaxils off HU?

4.7K views 37 replies 11 participants last post by  Regus  
#1 ·
I'm thinking about getting some JBL GTO628 coaxils to run for rear fill off my HU rear channels. Problem is they are 2 ohms. Will this fry my HY?
 
#11 · (Edited)
Or read the manual for the speakers. Most of the time when coaxials/components say 2 ohm, they are still safe to run off of the head unit. BTW, if it matters to you, you can get them brand new on amazon for $46.

From JBL's website:

True 4-ohm topology performance

For the most powerful performance, the GTO628 makes the best use of any amplifier by providing an optimum 2-ohm load. It uses a lower-impedance voice coil than a typical speaker to extract the most power and performance possible from all amplifiers engineered to drive loads of 4 ohms or less.
 
#14 ·
If you really want rear fill it would make more sense to follow what the manufacturer says and just get a pair of 4 ohm. I seriously doubt you will hear the difference overtop of the front stage.


Audio
Maximum power output ....... 50W Ă— 4
Continuous power output ... 22W Ă— 4 (50 Hz to
15 000 Hz, 5%THD,
4Wload, both channels driven)
Load impedance ...................... 4W to 8W Ă— 4


Copied from the manual online. No idea why it changed the impedance from U to W.
 
#17 ·
Will Infinity pay for your hu if you damage it? My main point is .....are the benefits worth taking the chance? the absolute minute difference you might possibly hear especially in a rear fill case are most certainly not worth taking the chance. Infinity, JBL, Harman can say anything they want to but my hu warranty is with pioneer and I will follow what they say.
 
#23 ·
It also can depend. I've actually had my Pioneer head unit thermal. I've also strangely had it thermal when connecting speakers with piezo tweeters to the head unit when testing. It seems Pioneer head unit amps do not like piezo tweeters, it must have caused inaudible amplifier osscilation, so if it's in a truck and you've got those piezo truck woofer boxes watch out.

So it shouldn't immediately destroy it but listening at loud levels can eventually cause heat to build up especially with 2 ohm speakers. Hopefully the thermal safety is working. I have on the rare occasion had an amplifier that didn't have a thermal safety properly working and burned up the output transistors but that was a long time ago. Basically you shouldn't be relying on your head unit's safety to keep you out of trouble. Just buy an inexpensive amplifier that's two ohm stable. You'll get louder and sound quality will improve with the added power.

The head unit is in an enclosed area with still air and in my car in particular if I had the heater on heat would build up in the dashboard and cause my head unit amp to thermal, it would have been worse if my speakers were 2 ohms.

I have an older Pioneer but it has the same chip amp as the newer ones. So it can depend on install too since I was thermalling and still might if I listen at very loud volumes for a long time with the heater on. And that's at 4 ohms per speaker.
 
#26 ·
Only reason running a 2 ohm speaker wouldn't be a good idea on an OEM HU is if your going to crank the volume up to full tilt!

More distortion at max level, yea that would be a problem.

You are not going to gain much by doing this but it is a noticeable difference.

If your hoping to to do this and getting a huge difference then you'll be disappointed.

Installed dozens of the 2 ohm JBL co-ax at a shop I worked at yrs ago and never had an issue. Other than they came back and added an aftermarket amp and/or HU .......NEVER did anyone come back because the OEM HU was bad due to the 2 ohm speakers.
 
#28 ·
So it sounds like those speakers aren't actually 2ohm speakers, the manufacture is telling you that so you think you're getting double the power. If they are truly 2ohm speakers then no, I wouldn't run them off of the HU if it isn't rated for 2ohms. Chances are, the speakers are closer to 3 or 4ohm speakers that will likely be ok for the HU; maybe they are just trying to appeal to the SPL crowd that thinks lower resistance means more power and better performance.

The way I look at it is that there are 2 possibilities:
1. They aren't actually 2ohm speakers and JBL is giving you very misleading info. They are trying to appeal to a certain crown that thinks lower impedance is better and so they will be fine.
2. They are 2ohm speakers and it's a bad idea to hook them up to your HU.

In both cases I'd look for different speakers.
 
#37 ·
There is actually a guy that chimes in on that thread at crutchfield that has an alpine hu that keeps shutting down with 2 ohm drivers hooked up to it. Infinity I believe. I still question the very small return in the end vs using a 4 ohm driver of similar sensitivity. To each their own.
 
#38 ·
I wonder if the guy on Crutchfield has run new wire to the Infinity 2 ohm drivers? As per the information from Andy W (which mirrors that on the Infinity website), when used as direct replacements for OEM speakers, their 2 ohm drivers would present a 4 ohm load once you took into account the overall impedance of the speakers and the OEM wiring loom and therefore will be fine when used with a HU or amplifier stable at 4 ohms. With uprated wiring the load could be low enough to cause a HU to shut down.

OP, are you planning on using these rear fill as replacements for stock speakers with the factory wiring? If so then you are probably fine to go ahead, although for peace of mind it might be worth checking with the HU manufacturer that it won't be an issue.