Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner

1 - 7 of 7 Posts

·
Registered
2002 chevy trailblazer_lt
Joined
·
3 Posts
Discussion Starter #1 (Edited)
I have searched the forum extensively, but am not finding a clear answer. I need to replace the rear speakers in my 02 TB but am having a difficult time locating 8 ohm replacements. Will the aftermarket 4 ohm speakers be OK with the factory head unit or will they overheat the unit? No Bose, and not using the Onstar.

If there is a thread- please direct me to it! thanks!
 

·
Registered
2008 gmc envoy_denali
Joined
·
437 Posts
Are you sure the stock speakers are 8 ohms? I thought I remembered fluking them at 4 ohms, but if you're reading 8 maybe try some Pro Audio speakers? Something from Parts Express, I've heard the Selenium 6" speakers in person and they sound great.
 

·
Registered
2002 olds bravada
Joined
·
214 Posts
I can second him, on my non bose, I had to pull the speakers out to install my sound deadining front is 4ohm, rear are 8ohm
I am sure that 4ohm would be ok for the rear, I think GM just put 8ohm in the rear so they were not as loud as the front, just to make the rear a fill in . I am sure GM of all companies would not spend the extra money to use a different type of amp for the rear channels in the head unit.
just my two pennies.
 

·
Registered
2009 chevy
Joined
·
6,431 Posts
Are you sure the stock speakers are 8 ohms? I thought I remembered fluking them at 4 ohms, but if you're reading 8 maybe try some Pro Audio speakers? Something from Parts Express, I've heard the Selenium 6" speakers in person and they sound great.
Keep in mind, that audio systems are measured in terms of impedance, not resistance.

A Fluke multi-meter will give the dc resistance of the coil windings. Impedance is the ac resistance offered by the coil winding while under power. This value varies, as the frequency of the ac voltage changes.

Impedance and resistance share ohms law results, so that when speakers are connected in series, the impedance values are added, as well, when in parallel, the values are reduced.

Generally, vehicle audio systems (because we only have a 12 volt supply) use 4 or 2 ohm amps and speakers. The thought being, that low load equals high volume.

The difference between front and rear may be a result of speakers being in series, or in parallel.
 

·
Registered
2003 gmc envoy_slt
Joined
·
361 Posts
I'm not an Audio guru but the "ohm" referred to in a speakers rating is not a DC resistance "ohm" rating but an Impedance(based on reactance to AC voltage and frequency) "ohm" value. Impedance cannot be measured with a simple ohmmeter. Try this: http://www.teamrocs.com/technical/pages/resistance_impedance.htm
and maybe a google search on audio impedance.:m2:
 

·
Registered
2008 gmc envoy_denali
Joined
·
437 Posts
I'm not sure how that related to my post, but I understand the concept. Regardless if you use 1, 2, 4, or 8 ohm speakers, the impedance will change with frequency, that is a given.
 

·
Registered
2002 chevy trailblazer_ls
Joined
·
5 Posts
I just put Inifinty 6032cf's in the front and rear. Had them in a week on the factory hu before upgrading that to a Sony MEX-BT3800U. Sounded nice on the factory hu.
 
1 - 7 of 7 Posts
Top