Problem setting gains on amps

[vincent714028 10+ year member]

After setting gains to minimum I've tried turning the head unit to 75% volume only to continue to hear music. Is this normal? There shouldn't be any music, right?

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[kross 10+ year member]

I believe this is normal. It does it on mine, too.

 

[vincent714028 10+ year member]

I decided to leave my volume at 30 as a max. I don't know what the max volume is for a pioneer 490ib but since the music was playing at minimum amp sensitivity I didn't want to blow my speakers.

So, with the head unit volume at 30 and subs disconnected I measured ac voltage. Now, my amp for the subs produces 125 watts at 4 ohms so if my math is correct I should measure about 22.36 volts. However, at minimum sensitivity I'm measuring .125 volts and at maximum I'm measuring about 8 volts.

I've tried 3 different meters, 2 dmm's and 1 analog. They all read the same.

Anyone have suggestions?

The amp in question is an Alpine MRV-1000.

 

[DBfan187 5,000+ posts]

use volume 61/62.

 

[IgnoreMe 5,000+ posts]

dont worry about it. you hear music because there is a signal coming through. the gain is on minimum, but minimum still means there is a signal.

dbfan187 has an oscilloscope and he has tested a few units and knows where they begin clipping.

set the volume to 60 (just to have a nice even number) and follow the gain tutorial. youll be fine.

 

[vincent714028 10+ year member]

Thanks. I'll try that.

 

[vincent714028 10+ year member]

After setting head unit volume to 60 I measured the ac voltage with amp at minimum sensitivity and the meter read 27.69 volts. This is already well above where I need to be. Then I turned down the volume to 50 and measured again where it read 10.5 volts.

Should I use this as my max volume or do I need a more powerful amp?

 

[vincent714028 10+ year member]

So, I ended up setting my maximum at 40 and turning up the gain to match the voltage. Great, right, I've got a thumper. Unfortunately my satellite amp is now reading 3 volts at max gain. Ssssooooo, to make the satellite amp work I have to increase my max volume to, say, 50 or 60. However, as before, when sub amp is set to minimum gain at a max volume of 50 the voltage is too high.

What should I do? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[kross 10+ year member]

Put a line driver on the RCA's that go to the satellite amp?

 

[vincent714028 10+ year member]

Thanks I'll look into that.

I also noticed today that on a particular song ( Smashing Pumkins, Bullet with Butterfly Wings) with a heavy bass line that woofer excursion is HUGE. It seemed like it was bottoming out, if that makes sense. The amp is 500x1 rms for a sub that is 300 watts max rms so I set the gain for 300 instead.

Is this type of woofer movement normal or is it distorting?//content.invisioncic.com/y282845/emoticons/eyebrow.gif.fe2c18d8720fe8c7eaed347b21ea05a5.gif

 

[vincent714028 10+ year member]

I think I figured out the problem. Some people suggest that you set your bass boost settings before you set the gain. This will reduce your max volume. Leaving settings at 0 when setting gains will even out the satellite amp and sub amp. Am I right?

 

[kross 10+ year member]

The bass boost on the amp should always be left at 0. All it does is add distortion.