I am upgrading the stereo system in my IROC in phases. Phase I is complete: an Alpine 7861 head unit, Alpine 6x9's and Boston Acoustics 4x10's in stock locations. I'm happy with the system so far, at normal to medium volume levels there is little audible distortion, but when I crank it up it distorts pretty quick. Whether the speaker(s) are distorting because they can't handle the 7861's output (rated 45wx4) or the 7861 doesn't have the power to sustain the volume levels I want, I don't know, but I suspect the latter is true. If so, I need more power, but I need some advice on how to install it.

I am getting a small amp, an Alpine MRP-F356 rated 4x75w or 2x180 . I'm not sure how to install this in the system. The 7861 has 2 pre-outs and an extra 'sub-out' (I think), but I'm not buying a sub right now. I'm guessing a typical installation would be to run one of the pre-outs to the amp and just connect my speakers to the amp. Or, are any of the following possible?

1. Bridge the 7861's amp (?) and drive the BA's with it, run the pre-outs to the amp, run it 2x180 and drive the 6x9's with it.

2. Forget the pre-outs and run high level inputs to the amp.

3. Some other combination of low and high level connections.

I really want to use the power in the head unit if I can. What are my options? How would you install it? I just have to wait on that sub. Thanks.


Amp Specs
http://www.competitionsound.com/mrpf356.html

 

87kevroc,
Since you have a 4 channel amp and your head unit has plenty of preouts, I would run your current 4 speakers off the alpine amp in 4 ohm stereo using two sets of RCA's. I couldnt tell from the info if this amp has separate gain, treble, bass etc controls.
Maybe somebody else will comment.
HTH

 

You can't bridge the internal amps in the head unit, but the head unit DOES have enough output power for your 4x6s. I would run 2 sets of RCAs to the amp and amp all 4 speakers. When you get a sub down the road, take the amp off the 6x9s and bridge those 2 channels for the sub, and run the 6x9s off the deck. Don't forget to set the crossover on the amp at "High pass" for the 4x6s.

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What jim said is how my system is set up. Only i have the RCA's running off the InLine Converter which is tapped into the 6x9 speaker wires. I did this becuase im running my stock swiveling Berlinetta radio, which doesnt have pre-outs.

You have the right idea, just run RCA's back to the amp, but thats not all. Dont forget about running Power Wire all the way back to the "+" terminal of the battery and the Remote cable run to either the Ignition fuse or to the Remote output wire in the back of your Head Unit..Oh yea and remember to run the Power Wire on one side of the car, and the RCA's on the other..

quite a pain in the *** ..

kev

 

Well it's obvious I'm kinda challanged in this area 4x10, thanks for being patient. Couple things I've learned since the original post. There are two (not three) pre-outs, the 7861 can control the rear set while at the same time disabling the rear speaker outputs. Also, the amp has a 5th channel for a sub.

So I could follow Jim's suggestion of simply amping all 4 and when I get the sub plug it in to the 5th channel. Or, I could drive the front speakers from the 7861, run the rear pre-outs to the amp, bridge it, and drive the 6x9's. This may be asking alot of my little 4x6 dash speakers. Of course I like deep, tight bass but I like vocals and guitar solos in front, as well as other mid and high range frequencies. I also may be giving up some level of control with this configuration as I don't see how I could limit low frequency up front.

Any other thoughts or ideas on this? It looks like the simplest idea is the best here, I just want to take advantage of all the knowledge and experience out there. Thanks.