If I get a new head unit with a power output of 4X50 watts and am already using a separate amp for my front speakers, what happens to the front two channels on the head unit? Are they useless to me? Can I bridge the channels and end up with 2X100 watts? Wishful thinking?

Also, with being able to use low-level outputs, will this increase the sound quality in my fronts? That's pretty much the whole idea of upgrading the HU, correct?

 

Bridging the outputs on a system that was never designed to be bridged is a bad idea. The outputs are not matched, so you will always be back-driving one of the outputs, and the impedance drop from bridging them will put undue strain on the internal amps. Bad idea...

Whether or not they are useless to you is another matter. You can run Bass Shakers with them, you could run a 3rd set of speakers with them to increase the sound stage, or you could leave them hanging...your choice.

I'm debating how to answer the last question to avoid unnecessary arguments without a long explanation, BUT...if you use quality shielded cable from HU to amp, yes, the low-level outputs will offer you a higher quality of sound.

 

Like MacGyver says...you cannot bridge the outputs. Another thing people need to understand about internal amplifiers on h/u is that when they state something like 4 x 50W (regardless if it is RMS or not) what this means is that each channel will make 50W, it does NOT mean that you will get 50W on ALL CHANNELS AT THE SAME TIME. Check your specs. If it says 50Wx4 ALL CHANNELS DRIVEN...you will get 50W x 4 on all channels, most do not say this.

To answer you last question, yes use the pre-amp out (avoid any distortion caused by the internal amp). I like to use coax cable with RCA connectors on them as the connection to the amplifier.

Just my 2 cents.

 

Thanks guys.

 

Okay, I'm ready to buy the Alpine 7894 which has an internal 4X60 watt amp. I'm going to use the RCA outputs for the fronts and the internal amp for my rears. Fronts are Focals (can't remember the model #, but it's the yellow ones.) Rears are Kenwood KFC xr600. Amp will be a Phoenix Gold 4 channel. I want to run the rears with the HU amp, the fronts with two channels of the PG amp, leaving two channels bridged on the PG amp for the JL audio stealthbox.

My question is this: Will the signal through the pre-amp outs be as clean as if I had purchased the Alpine 7895 HU (no internal amp) and purchased a 5 channel amp (JL Audio 500/5) and ran two channels to the fronts, two channels to the rears and one channel to the sub?

Thank you.

 

Anyone?

 

Yes, it will be clean but the 7895 will most likely sound better because it will have a better pre-amp stage (but then you are in a convertable).

Also your hu will not be putting out a true 60W (RMS or peak) to all channels unless it says ALL CHANNELS DRIVEN. Personally I would go with the 5 channel amplifier, it will be much cleaner than the internal amplifier and this is important as it is going to be reproducing the majority of the frequency range. Just look at the size of the power wire on your hu and compare it to the wire size on the amplifer...power out cannot exceed power in...small wire...small power in.

I think someone else on the board already went through exactly the same comparision you are trying. Try doing a search on Alpine 7895...sorry I cannot remember who it was.

BTW, I will be using a pre-amp only hu in my S2000 as soon as I feel like installing it...still enjoying the mechanical music .

 

Thanks Matrix. I'm going to take your advice and get the 7995. As soon as my SWI-X arrives from Lucid, I'm going to install the 7995 and JL Audio 5/100

BTW where is the SWI-X eye mounted? Doesn't it need to "see" the IR receiver on the HU?

 

post some pics when your finished your installation.

As for the eye...I would try a few locations around the ir reciever of the hu before you finish installing the trim. Can't say for sure as I have not tried this yet. Hopefully someone else can chime in also.

 

The LED has a pretty wide dispersion pattern, so you can get away with some crazy angles...on mine, the LED actually points more towards the passenger than the head unit, but it seems to have no problem working. Cover up portions of the faceplate with your hand while using the remote to see where the receiver LED is located, then point the transmitting LED in that general direction.