Running Infinity 2 Ohm Speakers off the Head Unit

[portishead]

Hi all;

I know I am probably killing this speaker upgrade thing to death but, I have been looking at the lower end speaker upgrade (below the Focal's) and I am finding the Infinity reference series seem nice sounding with the higest efficiency. The only thing blocking me from buying and installing them is the 2-Ohm rating factor. Will this potentially overheat and fry the factory head unit?

Another question is Crutchfield is saying 5-1/4" speakers for both front and rear. Metra is saying 6.5" will fit (without any brackets). I am wondering if anyone has done 6.5"'s and what aftermarket brackets you purchased to accomplish this (Scosche or otherwise?) or if no brackets are required at all. Has anyone measured the factory speaker openings in the front and rear of the Rav? If so please post your results.

I was also considering installing speaker baffles behind the aftermarket speakers to improve the bass response since the doors seem to be vibrating a lot from the rear of the factory speakers (robbing them of some output from the front).

I am not looking to invest a lot of money as this is a lease and I am planning on returning it in a couple of years but would like to enjoy the years of driving it while I have it.

Thanks in advance.

[The G Man]

You would want to match the impedence from the speaker to the amp output for rated power and efficiency.

[joebxr]

Your money is better spent on replacing the headunit. An Alpine will do very nicely and when you end the lease, you pop it out and put factory headunit back. This is an easy swap that will surprise you.

[aapitten]

I do not know a ton about car audio. But I do quite a bit with sound systems in theaters churches, etc. Could you just run the speakers in series to get the ohms up to a number the amp can safely drive? (fyi when speakers are in series the ohms are added. ex. two 2-ohm speakers in series=4ohms)

[SweNorth]

Originally Posted by aapitten

I do not know a ton about car audio. But I do quite a bit with sound systems in theaters churches, etc. Could you just run the speakers in series to get the ohms up to a number the amp can safely drive? (fyi when speakers are in series the ohms are added. ex. two 2-ohm speakers in series=4ohms)

It is possible, but not an optimal solution. First of all, you will end up with a mono system. Another problem is that you can only use one chanel from the headunit, because if you bridge the two chanels you will be back at 2-ohms again

[The G Man]

Yeah u definitely dont want to do that.

[Rickl]

Originally Posted by portishead

The only thing blocking me from buying and installing them is the 2-Ohm rating factor. Will this potentially overheat and fry the factory head unit?

Any amplifier has a wattage rating. To get that maximum rating transferred to the speaker, the speaker impedance must equal the amplifiers internal impedance. If the impedance of the speakers don't match, the power ( meaning heat) dissipated inside the amplifier will be greater than designed for, for any given volume level.

What this means (for example) is if the volume control was set to 50%, the volume at the speakers would be louder if the impedances match. It also means that the amplifier would run cooler if the imdedances match.

Since the amplifier will be running hotter than normal, it means the amplifier might reach it's maximum safe temperature at 80% volume, rather than 100% volume. Most modern amplifiers have thermal protection, so they will shutdown when they get too hot to avoid permanent damage. But as I said earlier, the volume of the speakers will be less than normal for any given setting, so the maximum volume out of the speakers might sound like only 70% of what it would be with the correct impedances.

Your idea to put 2 speakers in series to obtain the proper impedance would work. You just replace each single 4 ohm speaker with two 2 ohm speakers in series. It will look like a single speaker as far as the amplifier knows. I'm just not sure where you will get the space to add the extra speakers.

Rick

[joebxr]

Try removing 1 door speaker to see if there is a ohm rating on the back of the magnet...that might help you know what you can/can't do.

[aapitten]

Good point Swe, I had thought about the front-back balance, but kind of neglected the left right balance (hence STEREO system)... to much work with mono systems.

[The G Man]

I have done it b4, u can wire it so you will just lose the fader and not your balance and still have stereo. The problem is that now your amp is running at half power. The best thing to do is to just buy the right speaker.