Speakers impedance

tibimakai

San Dimas CA
:
USA
:
2014 CX-5 Touring
I have always wanted to know, how many ohms has per channel my setup.
Forgot to measure them, when I have replaced my speakers.
I have a Polk Audio amp for the door speakers, which can work down to 2 Ohm/channel.
My Infinity speakers are 3 Ohm speakers and the 3.5" Polks are 4 Ohm speakers.
I have looked at the schematics and it seems like the tweeters are installed in parallel with the door speakers.
I'm calculating the total resistance and it seems like it is 1.71 Ohm.
I'm wondering, how safe it is, to run them like this.
I'm also thinking about installing another set of Polks in the D pillars(maybe next month).
 
Your calculation is right.
Although its never a great idea to run under the rated impedance, I would not be too worried about being 15% under.
The problem with running under the rated impedance is that you can over draw your amp really easily.
So as long as you don't push the amp above 2/3 power you should be fine.

I'm not sure about your speaker setup, but I'm guessing you have 4 infinity speakers in your doors and then 2 polks in the dash??? (also assuming your Polk amp is a 4 channel amp)
If that's the case, throwing 2 tweeters on the back channels should not be a problem. If that's not the case...
Adding another speaker is probably not a great idea. It would drop your impedance down to 1.2; 40% under the rating (if you use a 4 ohm tweeter)
 
I have a set of component speaker in front and the Polks in the dash hooked up in parallel(factory wiring).
I also have the same component set in the back and I'm thinking about adding, the 3.5" Polks in the back in the d pillar. This way they would be equal.
The amp, is a 4 channel Polk PA660.4.
 
I think you will be ok in the short term, but remember that amp is class A/B and those tend to want to run hot. I used those series of Polks before and they had some heating issues even on 2 Ohm nominal loads. Adjust your gains properly and keep an eye on the amp's temperature but I think you will be ok. Once the speakers heat up a little and more than likely from the factory wiring you will be closer to 2 Ohms once it is all said and done at the amp.
 
The Polk amp is rated at 75W x 4 channels @2 ohms. (For reference, most after market in dash receivers are either 25W x 4 or 50W x 4)
You will have plenty of headroom, so I wouldn't worry about going a little under the impedance rating.

I have a similar setup with 3.5" polks in the front and then Tweeters in the d pillar.
Only real difference is that my door speakers are 4ohm. But my amp is rated at 50W x 4
 
I have set the gain properly, I have a scope. It heats up quite a lot, but I did not have any issues yet. I live in LA area, where it gets pretty hot as well.
For a while, I will be fine with this setup then.
Thank you for your answer. I feel better now.

I'm starting to upgrade my setup and I'm already started buying new speakers.
Yesterday, I have received the first set, Focal PS165FX(Flax series).
I'm even thinking about getting the PS165F3, if Ican find a good deal somewhere.
 
I have set the gain properly, I have a scope. It heats up quite a lot, but I did not have any issues yet. I live in LA area, where it gets pretty hot as well.
For a while, I will be fine with this setup then.
Thank you for your answer. I feel better now.

I'm starting to upgrade my setup and I'm already started buying new speakers.
Yesterday, I have received the first set, Focal PS165FX(Flax series).
I'm even thinking about getting the PS165F3, if Ican find a good deal somewhere.

One reason I stopped using those Polks amps. They just run hot overall. Probably not the most efficient class A/B design but they are also inexpensive.
 
They cost me, $40 each broken from the bay and I have repaired them, for a couple of bucks.(PA660.4 & PA880)
My other question it would be, if I will install the Focal component, what should I do with the 3.5" Polk.
Right now they are connected, but with these better components, I'm wondering if they are still needed?!
Should I leave them there connected ion parallel with them, or I should remove them?
 
I would say remove them. The Focals should be engineered to work for the audio spectrum as a set. Properly tuned they should sound fine.
 
Thanks, that is what I have thought that I should do.
I will just hold off on the d pillar install than and get another set of Focals in the door.
 
Back