ALPINE mrp-m1000 Gain Setting Problem

[motoamster13200 10+ year member]

Im having issues setting my gain. My alpine f450 amp for my speakers went fine....but with my sub amp mrp-m1000 alpine for a JBL 12gti I can't even get close to setting the gain inless my volume is on max and the gain is all the way up. I am using a -3 60hz test tone trying to get 45.82 V for 700watts at 3Ohms. so the max volts i can get out of it is around 42 if the volume is above 80% with the gain maxed out. Something is not right. all equalizers, boosters, filters turned off , set to the lowest. I am running 0 gauge wire and have a kenwood 5v Kdc-x891. This amp should be able to put out at least 600RMS at 3 Ohms... maybe not?? Any ideas? Thanks

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[lvjeffro 10+ year member]

I might be wrong here but the alpine mrp-m1000 is a 2 or 4ohm amp I don't know if it is stable at 3ohms or not...That might be a problem... try running amp at 4 or 2 ohms and see if it makes a difference...HTH

 

[GLN305 10+ year member]

I think what you may be seeing is impedance rise with the subwoofer causing less power output. Try measuring the voltage with the sub disconnected and see what the highest voltage you can get is.

 

[GLN305 10+ year member]

I might be wrong here but the alpine mrp-m1000 is a 2 or 4ohm amp I don't know if it is stable at 3ohms or not...That might be a problem... try running amp at 4 or 2 ohms and see if it makes a difference...HTH

It will be fine at 3 ohms. The amp is 2 ohm stable meaning that it can handle loads as low as 2 ohms. This means anything above 2 ohms is OK.

 

[BoxdGM 10+ year member]

don't your turn the sub level to the max on the head unit for setting the gain? wasn't sure if ya missed that

 

[motoamster13200 10+ year member]

I think what you may be seeing is impedance rise with the subwoofer causing less power output. Try measuring the voltage with the sub disconnected and see what the highest voltage you can get is.[/QUO
When I was trying to set the gain, the sub was disconnected.

 

[motoamster13200 10+ year member]

don't your turn the sub level to the max on the head unit for setting the gain? wasn't sure if ya missed that

I didn't do this. I thought everything was supposed to be at 0 on the head unit...such as bass boost, sub level, etc.

 

[BoxdGM 10+ year member]

I turned loud mode, and all bass enhancers off and set sub level to +7 (max) and was able to reach voltage with around 1/3 gain at 3/4 HU volume on a -3 50hz tone. I saw u had all the bass boosts off but does your hu have a sub level setting?

 

[BoxdGM 10+ year member]

and that amp is 1000 at 2ohms I think and 500 at 4 so I'm sure you could get 600 easily at 3

 

[motoamster13200 10+ year member]

I turned loud mode, and all bass enhancers off and set sub level to +7 (max) and was able to reach voltage with around 1/3 gain at 3/4 HU volume on a -3 50hz tone. I saw u had all the bass boosts off but does your hu have a sub level setting?

My Headunit has a sub woofer adjustment. you can put it anywhere from -15 to +15. I had this on 0. If you are supposed to have this on 15? I will try it. Thanks

after you set the gain, did you leave the sub at 7? I always thought the sub sounded a little more distorted at 15 verses 0

 

[motoamster13200 10+ year member]

and that amp is 1000 at 2ohms I think and 500 at 4 so I'm sure you could get 600 easily at 3

Yes 600rms 4 Ohms and 1000 at 2 Ohms. I am looking for a bpx amp though.

 

[BoxdGM 10+ year member]

if you set your gain at +7 then change it to 15 it would cause clipping but if you set it at 15 you don't have to worry about sending a signal stronger than the amp is expecting so you can back it off a few levels for head room. if you set the gain at 3/4 vol and +15 and a test tone you will probably never blow your sub with music

 

[motoamster13200 10+ year member]

if you set your gain at +7 then change it to 15 it would cause clipping but if you set it at 15 you don't have to worry about sending a signal stronger than the amp is expecting so you can back it off a few levels for head room. if you set the gain at 3/4 vol and +15 and a test tone you will probably never blow your sub with music

That makes sense. Thanks. Ill give it a try.

 

[Fine Vol 10+ year member]

I have the amp on one RF p3 and it does a good job but after 25 min. it gets to hot and lowers its volume.

 

[pjhabit 10+ year member]

Yea, if you have an alpine hu. Put your sub level to +15 then set the gains.