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Hi folks...

Neatness aside, is there any real advantage or disadvantage of having 2 two-channel amps instead of a four-channel amps to power four coaxial speakers (no subs)? Let's assume that there is no major difference in wattage. For example, would there be any advantage or disadvantage of having two separate 50W x 2 amps as opposed to a single 50W x 4 amp? Again, neatness is not an issue, but I'm more concerned about current draw from the alternator and battery. I assume that total RMS wattage of all amps is the big concern, not necessarily how many amps you have, so I assume that there is no real difference between having two 50W x 2 amps and a single 50W x 4 amp, but I would prefer to ask the opinion of others first. :wink:

I currently have a two-channel amp to power my front speakers. I've been daydreaming about amplifying my rear speakers as well, but I'm not sure whether to keep my existing two-channel amp and add a second two-channel amp to power the rears, or to get a four-channel amp to power all fours (which would put my two-channel amp to pasture).

Just an idea... I'm happy with the way my stereo sounds right now. :)

Any ideas or suggestions would be greatly appreciated. Thank y'all. :)
 

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It'll be significantly cheaper to buy a second 50WX2 amp than getting a single 50WX4 amp. A 50WX4 amp is relatively high end and will cost you a lot, assuming that is RMS wattage you're talking about.

The draw on your alt. won't be any different. The only thing to watch for when wiring multiple amps is to insure you've got a fused distribution block for your power and a single grounding point for both of them so you don't end up with a ground loop.

If space isn't an issue I think another 2 channel amp is the way to go for what you want.

Having said that, you won't notice a significant difference by amping your rear fill speakers. I think your money is better spent on a head unit, sound deadening material, or bass.

Check out my car domain page if you want to see how I did all this.
 
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machman said:
It'll be significantly cheaper to buy a second 50WX2 amp than getting a single 50WX4 amp. A 50WX4 amp is relatively high end and will cost you a lot, assuming that is RMS wattage you're talking about.

The draw on your alt. won't be any different. The only thing to watch for when wiring multiple amps is to insure you've got a fused distribution block for your power and a single grounding point for both of them so you don't end up with a ground loop.

If space isn't an issue I think another 2 channel amp is the way to go for what you want.

Having said that, you won't notice a significant difference by amping your rear fill speakers. I think your money is better spent on a head unit, sound deadening material, or bass.

Check out my car domain page if you want to see how I did all this.
Thank you for your suggestions! Yes, I checked out your CarDomain page a long time ago. It looks like you have an awesome setup for your RAV4. Don't worry... in my old Tercel, I once held down an amplifier under the seat with Velcro too. :p Mind you, it was one of those really small Jensen amps that I used to power the 4" speakers on my door panels.

Two things...

a) Is it absolutely imperative to have a distribution block if I want to hook up more than one amp?

b) If I choose not to use a distribution block (assuming that it is OK not to use one), do I still need to ground each amp to the SAME spot?

Given the complexity of a multi-amp setup, I might as well get a singe four-channel amp, or just settle for the two-channel amp that I have now, which already sounds pretty good for my needs... no pounding bass, but clean highs and mids (thanks to my amplified front Infinity speakers), and pretty decent bass (mostly from my unamplified Rockford speakers in the back). I'm sure that I can score a good deal on four-channel amps this Boxing Day, but I won't hold my breath. :lol:
 

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EHinthe604 said:
Thank you for your suggestions! Yes, I checked out your CarDomain page a long time ago. It looks like you have an awesome setup for your RAV4. Don't worry... in my old Tercel, I once held down an amplifier under the seat with Velcro too. :p Mind you, it was one of those really small Jensen amps that I used to power the 4" speakers on my door panels.

Two things...

a) Is it absolutely imperative to have a distribution block if I want to hook up more than one amp?

b) If I choose not to use a distribution block (assuming that it is OK not to use one), do I still need to ground each amp to the SAME spot?

Given the complexity of a multi-amp setup, I might as well get a singe four-channel amp, or just settle for the two-channel amp that I have now, which already sounds pretty good for my needs... no pounding bass, but clean highs and mids (thanks to my amplified front Infinity speakers), and pretty decent bass (mostly from my unamplified Rockford speakers in the back). I'm sure that I can score a good deal on four-channel amps this Boxing Day, but I won't hold my breath. :lol:
You're most welcome. It's tough getting good advice on this kind of good stuff. ...having said that, take my advice with a grain of salt too, it's only from personal experience.

Answers to your questions:

1) YES ! ! ! You'll want a main fuse within 18" of your battery terminal, and a fused distribution block wherever you decide to split off to your two amps. You can pick them up on ebay for $30. The main fuse should be able to hold the amount of power both amps will draw, the fuses in your distribution block should hold the same size fuse as the fuse in the amp it's sending power to. This helps prevent blowing your amps up and prevents your car from catching fire.

2) In order to prevent a ground loop and other problems, be sure to ground both amps to exactly the same spot. You can get an unfused distribution block for this purpose for about $10 on ebay. If you don't use an unfused distribution block just be sure to use one bolt to ground both wires to your frame, and be sure to make sure you've sanded it down to the bare metal.

No question, a 4 channel amp install is easier. If you've got the funds, do it. One thing to keep in mind is to make sure it's well matched to your speakers. Infinities are notoriously shitty sounding when under powered. Mine will handle 80W RMS and I power them with 50W RMS and they're fine. Any less than that and they might as well be $50 speakers instead of $200 speakers.

There are some set up issues to keep in mind too that you may or may not have addressed. If your from speakers have a built in crossover, be sure to run "full" pass to them from your amps crossover because the speakers can identify what frequencies they can best handle. If your speakers don't have crossovers, you'll need to tweak your high pass settings a bit to match the frequency handling of the appropriate speaker pairs.

Hope this helps.

Cheers,
 
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machman said:
You're most welcome. It's tough getting good advice on this kind of good stuff. ...having said that, take my advice with a grain of salt too, it's only from personal experience.

Answers to your questions:

1) YES ! ! ! You'll want a main fuse within 18" of your battery terminal, and a fused distribution block wherever you decide to split off to your two amps. You can pick them up on ebay for $30. The main fuse should be able to hold the amount of power both amps will draw, the fuses in your distribution block should hold the same size fuse as the fuse in the amp it's sending power to. This helps prevent blowing your amps up and prevents your car from catching fire.

2) In order to prevent a ground loop and other problems, be sure to ground both amps to exactly the same spot. You can get an unfused distribution block for this purpose for about $10 on ebay. If you don't use an unfused distribution block just be sure to use one bolt to ground both wires to your frame, and be sure to make sure you've sanded it down to the bare metal.

No question, a 4 channel amp install is easier. If you've got the funds, do it. One thing to keep in mind is to make sure it's well matched to your speakers. Infinities are notoriously shitty sounding when under powered. Mine will handle 80W RMS and I power them with 50W RMS and they're fine. Any less than that and they might as well be $50 speakers instead of $200 speakers.

There are some set up issues to keep in mind too that you may or may not have addressed. If your from speakers have a built in crossover, be sure to run "full" pass to them from your amps crossover because the speakers can identify what frequencies they can best handle. If your speakers don't have crossovers, you'll need to tweak your high pass settings a bit to match the frequency handling of the appropriate speaker pairs.

Hope this helps.

Cheers,
THANKYOUTHANKYOUTHANKYOU!!! Thank you very much, machman! Frankly, when it comes to car stereos, I'm a total green. I was on the verge of installing two amps without a distribution block, merely due to COST of all things... tsk tsk tsk! :oops: Now, I will definitely use a distribution block for both power (fused) and ground (unfused).

Actually, I took the plunge and got a good deal on an amp and a power kit. (Actually, the savings aren't as obivous, since the amp kit doesn't come with RCA interconnects :( but I think I still got a good deal.) Now, I will have to send my MTX amp back to the repair depot in Kelowna, BC and put the new Alpine amp in its place (under the driver seat). When I get the MTX amp back from repair, I will relocate it to under the passenger seat with the new wiring kit. At that point, I will then install the distribution blocks for both power and ground. Man, it will cost me a few more bucks, but hey, better safe than sorry, eh? 8)

You are correct about how crappy Inifinity speakers sound when underpowered. When I first switched my front speakers to the Inifinity, they didn't sound that much better than my stocks... definitely better highs and mids, but so-so lows. I had kept my MTX amp on high-pass because I thought that Inifinity speakers simply could NOT handle the bass. However, just the other day, I switched my MTX amp from high pass to full pass. Man, I was blown away by the difference. :shock: Initially, I had kept it on high pass because I thought that the Inifinity could only handle high frequencies, given my experience without the amp. However, with the amp on high pass, it just sounded AWESOME.

Right now, I plan to use my Alpine amp to power the Inifinity speakers in front and my MTX amp to power my Rockford Fosgate speakers in the back. However, I will have to play around with the crossover settings on the amps once both amps are in operation. Currently my (unamplified) Rockford Fosgate speakers have decent bass, but I'm sure that once I amplify them, they will sound awesome, to the extent that I will cancel plans for a subwoofer. :p

I will keep the forums updated. Thanks again, machman. :)

PS: ONE MORE THINK, machman... how did route your ground wire from one amp to the grounding distribution block under the other seat?

PPS: Actually, ignore the last question. :p I just went outside to check. There is enough room under the centre console to route the ground wire from under one seat to under the other seat. :lol:
 

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You're right. If you remove the center console there is a bundle of wires that runs under it from side to side. I just tucked my 8 guage wire beside it so it wouldn't rub.

Sounds like you're ready to rock. Let me know if you have any more questions. I'll do my best to help.
 
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machman said:
You're right. If you remove the center console there is a bundle of wires that runs under it from side to side. I just tucked my 8 guage wire beside it so it wouldn't rub.

Sounds like you're ready to rock. Let me know if you have any more questions. I'll do my best to help.
Hi again, machman...

Other random thoughts that came across my mind after I sent the more recent reply... I am a total green when it comes to installations, so I don't mind spending an extra buck or two to get it done professionally, but I'll definitely call the shots.

Right now, I have 10 gauge power wire running from the battery, along the firewall, to an existing grommet on the driver side, under the side trim, to my existing MTX under my driver seat. Here are the mods, in the following order (some of which I have already mentioned):

1. Replace the MTX with the new Alpine amp, using all existing wiring. Send the MTX to the service depot in Kelowna.

2. As soon as I get my MTX back, I'll install it under the passenger seat.

3. Run a NEW 4 gauge wire from the battery (with an AGU fuse in a glass holder), through the exising passenger side, to terminate to a fused distribution block, mounted in the interior side of the firewall.

4. Re-route my existing 10 guage power wire (running to my passenger side) to the newly-mounted fused distribution box.

5. Run a NEW 8 gauge wire from the fused distribution block to the relocated MTX amp under the passenger seat.

6. Install a NEW ground distrubition block next to my amp under the driver seat.

7. Run a NEW 8 gauge ground wire from under the passenger seat to the newly-installed ground distribution block under the driver side. Also, connect the existing 10 gauge ground wire from the under-driver-seat amp to the ground distribution block.

8. Run a NEW 4 gauge ground wire from the ground distribution block to the existing drilled ground post (drilled drilled the installation of my original amp).

One more thing... regarding the power-on wire... should I run two separate power-on wires from the head unit, or should I simply daisy-chain the power-on from amp to amp? Given that I am only running two amps, I don't think that I need to relay the power-on wire.

Another thing... if I used a FUSED power distribution block, do I still need to fuse each "output" wire? (Of course, I plan to have an AGU fuse holder on the "input" wire.) If I don't need to fuse each individual "output" wire, I can retire my existing Stinger slot-style fuse holder.

Thanks again!!!! :) :) :)
 
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