85 Vette, I bought a 4 channel amp. I want to hook up the rear speakers to one channel. I have door speakers AND front speakers. Can I hook all four up to the other channel?

 

Hmm so you want to run 5 or 6 speakers with a 4 channel amp?

If you are going to run 5 you will need to do some creative wiring. I am pretty sure you are saying that you want to run 6 speakers. Couple questions and then options:

What amp are you running? Specs? Is it 2 ohm stable?

You can run the entire system one of 2 ways. If the amp is 2 ohm stable you run the front 4 speakers off of channels 1/2 in parallel for a 2 ohm load and proper stereo imaging. (Setting of the gains here important) Then you run the rear 2 speakers off of channel 3/4.

If the amp is NOT stable to 2 ohms then you would have to pick which of the front 2 speakers are the least important to you (IE play the smallest amount of frequency range or to you sound the worst) and wire those 2 speakers with the rear 2 speakers in series for an 8 ohm load to the amp for channels 3/4. Then run your best set of front speakers to channels 1/2.

When you send the amp an 8 ohm load you do cut the power to those channels but can be corrected (somewhat) with some additional gain to those speakers.

G'luck
Fej

 

Brand: Phoenix Gold R8.0;4
RMS Power Output: 125W x 4 @ 2 Ohm
Peak Power Output: 200W x 4 @ 2 Ohm
Signal To Noise Ratio: 110dB
Frequency Response: 20Hz-20kHz
Built-In Crossovers: Variable 18dB
THD @ 4 Ohm RMS Power: 1%
Ohm Load Stability: 2 Ohm
Low Level Input: Yes
Built in Cooling Fan: No
Bass Control ****: No

I want to run my 4x6 front speakers and my door speakers on channels#1 and #2. Channel #3 and #4 would run my 6x9 set in the rear. I thought I may be able to parallel the fronts together, or
should I just pick the best set out of the 2 for the front set?

 

Nah that amp is 2 ohm stable you are golden

Run the front 4 speakers in parallel for a 2 ohm load to the amp on channels 1/2. Run the rear 6x9's on channels 3/4. Which headunit?

Basic set up.

Headunit at about 75-80% of max volume. (IE 27 out of 35 for Alpine)
Start with the gains on the amp all the way down for both channels.
Pick a CD you know well with a good dynamic range (rock music usually good here)
Unplug channel 3/4 RCA's (if you ran two sets, if not unplug speakers) and slowly turn the gain up on channels 1/2 (while at that initial starting volume on the headunit) until you start to hear distortion in the speakers OR you reach a volume that you would consider your MAX listening (usually will distort first). Turn it down a hair and call it good.

Do the same for channels 3/4 if imaging is not important to you. If it is "blend" in the rear speakers to accompany the fronts without overpowering them. The rear 6x9's are probably your main source for bass so I would probably think you would want decent power to them.

Remember the volume that you set the headunit at as this is your MAX volume without introducing too much distortion to the speakers. Most headunits will send a relatively clean signal up to around 75-80% of max volume.

Crossover points:

Somewhere around 100-120hz for a high pass on the front channels. (depends on quality and if you sound deadened or not, also if they are 5.25" or 6.5") Depending upon the quality of the 6x9's in the rear you could try to get them to play down around 60hz. Below that I doubt they will handle. May need them up around 80hz.

G'luck
Fej

 

with fej
Your amp will be fine but I'd be worried about your 4X6"s. With that kind of power, not only do you need to set your high-pass to above 100Hz I would also recommend a 500 Hz passive Bass Blockers on them.

 

Good idea on the 4x6's Knew. Something to move the crossover point up a bit on them is a good idea. I know they used to make "bass blockers" in name, probably worth a search. Could probably put something together out of Radio Shack with a bit of research to save those poor things from trying to play actual bass. Without one you will most likely be limited by this speaker in terms of your gain/volume settings as this speaker will distort trying to play the midbass region.

Fej

 

I would run the rears with the doors on the rear ch. Reason being your 2 ohm load will increase power to the 4 speakers, better to have usable power to the bigger speakers then turning down the gain on the front speakers. Then run the fronts off the front ch(1/2).