Multiple amp wiring information

[MrVicious97]

Ive been doing some searching for information on this topic but have come up short. I was wondering if some of you audio gurus would mind endulging a few noob questions about amplifier installation.

 

I have an alpine MRP-F450 4xchannel amp pushing a pair of infinity ref components in the front and infinity ref speakers in the rear. I also have 2 alpine type r 10" subs being powered by 2 alpine MRP-M650 amps. My questions are as follows.

 

1) What is the best way to wire signals to the mono amps? The 4xchannel has 2 rca passthroughs. I have tried to use Y connecting rca's to connect the 4xchannel to each of the mono amps.

 

2) Would it be better to wire the subs in series with the amps or parallel. Ive been recieving a lot of distortion when the system is running high.

 

Any other info would be significantly appreciated. Thanks in advance for any help anyone can offer.

[mevanvt]

Ive been doing some searching for information on this topic but have come up short. I was wondering if some of you audio gurus would mind endulging a few noob questions about amplifier installation.

 

I have an alpine MRP-F450 4xchannel amp pushing a pair of infinity ref components in the front and infinity ref speakers in the rear. I also have 2 alpine type r 10" subs being powered by 2 alpine MRP-M650 amps. My questions are as follows.

 

1) What is the best way to wire signals to the mono amps? The 4xchannel has 2 rca passthroughs. I have tried to use Y connecting rca's to connect the 4xchannel to each of the mono amps.

 

I'd use the y's but if you aren't getting enough of a signal you will need a line driver.

 

2) Would it be better to wire the subs in series with the amps or parallel. Ive been recieving a lot of distortion when the system is running high.

 

Do you mean wire the subs to each other in parallel or the voice coils (I really hope you mean voice coils)? Why did you go with 2 amps for the subs? This will cause problems b/c it will be difficult to set the gains the same. You could be having some distortion because of this but most likely it is because you have the gains set too high and it is clipping. Please post some more info on those subs and people will be able to help you out a bit better.

 

Any other info would be significantly appreciated. Thanks in advance for any help anyone can offer.

 

1

[MrVicious97]

1

Thanks mevanvt.

The subs are alpine type r 4Ohm subs. They are SWR-1042D. 500W RMS/1500W Peak. I decided to go with 2 mono amps because they produce 400W RMS. Driving 2 subs off of 1 amp is completely out of the question.

[mevanvt]

Thanks mevanvt.

The subs are alpine type r 4Ohm subs. They are SWR-1042D. 500W RMS/1500W Peak. I decided to go with 2 mono amps because they produce 400W RMS. Driving 2 subs off of 1 amp is completely out of the question.

 

Wire those voice coils in parallel. Then you can pull 600 watts rms from those amps b/c they'll be seeing 2 ohms. You just need to be careful not to set the gain too high because you might blow them. I don't have any experience with alpine so I don't know how much of a pounding they can take but from what I remember hearing about them they should be able to take a good deal of abuse.

 

As for matching the gains I would use an rta or a voltmeter. I can't remember how to do this but there is a tuturial on JL's site about it.

 

edit: Are these boxes in sealed enclosures or vented? Do they share a common air chamber or do they have their own chambers?

 

-Mike

[MrVicious97]

Wire those voice coils in parallel. Then you can pull 600 watts rms from those amps b/c they'll be seeing 2 ohms. You just need to be careful not to set the gain too high because you might blow them. I don't have any experience with alpine so I don't know how much of a pounding they can take but from what I remember hearing about them they should be able to take a good deal of abuse.

 

As for matching the gains I would use an rta or a voltmeter. I can't remember how to do this but there is a tuturial on JL's site about it.

 

edit: Are these boxes in sealed enclosures or vented? Do they share a common air chamber or do they have their own chambers?

 

-Mike

They are in a dual sealed enclosure. They do not share an air space. This is just to tide me over untill I get get some custom side well mounted sealed boxes.

[Boulderguy]

Do your sub amps have mono or stereo inputs? And the pass-thrus, two RCA outs or two sets of stereo RCA outs? If it were me, I'd just send the rt channel to 1 sub amp, the left channel to the other. Summing those twowith Y-connectors may cause impedance issues leading to your distortion problem.

 

About the distortion, can you be more specific about the problem?

 

And +1 on the parallel wiring, just keep the gains set reasonably.

[MrVicious97]

Do your sub amps have mono or stereo inputs? And the pass-thrus, two RCA outs or two sets of stereo RCA outs? If it were me, I'd just send the rt channel to 1 sub amp, the left channel to the other. Summing those twowith Y-connectors may cause impedance issues leading to your distortion problem.

 

About the distortion, can you be more specific about the problem?

 

And +1 on the parallel wiring, just keep the gains set reasonably.

 

The subs have stereo inputs. I have them wired with the + and - leads connected to the outside inputs. The subs also have jumpers between the 2 - inputs and between the 2 + inputs.

The 4channel has 1 pair of outputs=1right and 1 left. The pics be low are my amps and sub. The distortion problem is a garbled crackling sound when the volume is cranked up a bit. I know that the amps should be able to handle the kind of power I am asking from them because when I only had 1 amp hooked up it hit hard and accurately.

[Boulderguy]

So the distortion is in the subs, not the mains, right? Are you running the sub amps mono or stereo?

 

Also - this will seem unrelated but bear with me - does your main amp have 2 or 4 gain adjustments total? And are the fr/rr mains both X'ed over at the same point?

[mevanvt]

The subs have stereo inputs. I have them wired with the + and - leads connected to the outside inputs. The subs also have jumpers between the 2 - inputs and between the 2 + inputs.

The 4channel has 1 pair of outputs=1right and 1 left. The pics be low are my amps and sub. The distortion problem is a garbled crackling sound when the volume is cranked up a bit. I know that the amps should be able to handle the kind of power I am asking from them because when I only had 1 amp hooked up it hit hard and accurately.

 

One more question. Are you running a cleansweep or other equivalent product or are you running high lvls/LOCs? Sounds like you might not be getting enough voltage to your preouts on the sub. Try splitting them like the above poster said and see if that helps.

Question: Is it ok to run one sub for L and one for R or will you get a funky sound?

[Boulderguy]

OK, just looked at the Alpine site manuals for those models. Strange that the sub amps, which are monoblocks, require a stereo input. It cautions that using a mono input may reduce output.

 

This can mean a few different things - maybe the main amp output doesn't have enough juice to split between two sub amp inputs at volume (impedance issues with the Y-connector)?

 

Or maybe when you had them hooked up previously you used one input on the sub amps, thereby reducing final output and not overtaxing the amps?

 

Maybe the input into the main amp - before going to the sub - has problems at volume (this would cause distortion in all speakers, not just the subs)?

 

This of course assumes all the obvious reasons why speakers distort arent' a problem - gains too high, adequate ground, unrealistic expectations, etc. For now, I'd try going with a single channel output from the main amp to each sub amp & see if it solves the problem.

[MrVicious97]

So the distortion is in the subs, not the mains, right? Are you running the sub amps mono or stereo?

 

Also - this will seem unrelated but bear with me - does your main amp have 2 or 4 gain adjustments total? And are the fr/rr mains both X'ed over at the same point?

My amp has 2-gain adjustment 1 gain knob for the 1 and 3 speaker=left side, and 1 for 2 and 4 speaker=right side. I dont know if this will help but my power is through a fused distrobution block. My grounding is through a block as well.

[MrVicious97]

One more question. Are you running a cleansweep or other equivalent product or are you running high lvls/LOCs? Sounds like you might not be getting enough voltage to your preouts on the sub. Try splitting them like the above poster said and see if that helps.

 

Question: Is it ok to run one sub for L and one for R or will you get a funky sound?

I do not have a CS or 3sixty yet. I am only running a line out converter.

[tdjanke]

OK, just looked at the Alpine site manuals for those models. Strange that the sub amps, which are monoblocks, require a stereo input. It cautions that using a mono input may reduce output.

 

This can mean a few different things - maybe the main amp output doesn't have enough juice to split between two sub amp inputs at volume (impedance issues with the Y-connector)?

 

Or maybe when you had them hooked up previously you used one input on the sub amps, thereby reducing final output and not overtaxing the amps?

 

Maybe the input into the main amp - before going to the sub - has problems at volume (this would cause distortion in all speakers, not just the subs)?

 

This of course assumes all the obvious reasons why speakers distort arent' a problem - gains too high, adequate ground, unrealistic expectations, etc. For now, I'd try going with a single channel output from the main amp to each sub amp & see if it solves the problem.

 

Typically mono amps have a stereo RCA in order to obtain bass freq content from either the left or right channels. Some source units have a left and right sub output, some have 2 outputs, both with the same signal and some may have one. On the amplfier side of things, if there are 2 inputs use them. Each input is weighted appropriatly ( 1/2 + 1/2 = 1 ) If you only use 1 input, you will get half the output because the amp expects the other input to contain signal as well. There's nothing involved with the impedance of the Y adapter.

 

If you look at home powered subwoofers, some have 1 input, some have 2 and some of those have 2 have a selection switch to choose how many of the 2 inputs you are using. This simply adjusts the weighting of each signal so that you get maximum output.

 

 

As for the distortion issue, my vote is for improperly set gains.

[Boulderguy]

I suppose what struck me as odd about the mono/stereo inputs is there's no way to use a single channel input w/o losing output.

 

I'd agree about gains being most likely, but check the quality of your ground - not the block, but where you connect to the frame. Is it clean? No paint? You didn't ground to the spare tire, did you?

 

At 2 ohms, each of those sub amps is pushing 600w (in theory), so total you're looking at a roughly 1500w rms system - do you have the power capacity to feed it properly?

[MrVicious97]

I suppose what struck me as odd about the mono/stereo inputs is there's no way to use a single channel input w/o losing output.

 

I'd agree about gains being most likely, but check the quality of your ground - not the block, but where you connect to the frame. Is it clean? No paint? You didn't ground to the spare tire, did you?

 

At 2 ohms, each of those sub amps is pushing 600w (in theory), so total you're looking at a roughly 1500w rms system - do you have the power capacity to feed it properly?

My power kit is rated to handle 100 amps. The ground was drilled though the franme under the rear passenger seat. Definitely did not ground to the spare tire. I might just have to get 0 gauge wiring to accomodate the power requirements of all the amps.

 

Thanks again to everyone who has offered me assisstance on this issue! I feel like such a noob

[Boulderguy]

2g cable is plenty, just be sure the spot you grounded to is clean, as in paint removed & bare metal. Makes a big difference. Otherwise it's probably gain adjustment.

 

Don't feel like such a freshman, you know a lot more than many of the posters we see on here!

[Boulderguy]

Hey, one other idea, a long shot - try using the hi level inputs on the main amp instead of the LOC you have upstream. Should be able to use the rear speaker leads for it pretty easily.

[MrVicious97]

Hey, one other idea, a long shot - try using the hi level inputs on the main amp instead of the LOC you have upstream. Should be able to use the rear speaker leads for it pretty easily.

I filed down the grounding area a bit to expose the bare metal without the coat, it helped quite a bit but Im still not getting the punch from the subs that I expected. When I was running a single type r off of a single amp it was hitting pretty hard. Figured 2 would nearly blow my windows out. I do not believe my expetations are unreasonable for these specific subs. I think I need to have someone with a little more expertise in this field to lend a hand tunning my amps. Thanks again for the advice.