Is some headlight dimming normal?

[Steveopevo 10+ year member]

I'm running 840 watts rms, did the big three plus Optima battery and h/o alternator and still getting dimming during heavy bass notes. I did all my upgrades because I'm planning on a bigger system but i'm concerned that with all I've done I'm still dimming. I've read some posts that say some dimming is to be expected due to voltage drops.

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[BnGRacing 10+ year member]

Are you running your amp

The other thing is 'RMS'. What the hell does that mean? Honestly, no one really knows as it's a pretty useless number. Average power over a given time is much more useful. With that, your 840w RMS amp may be producing an average power of 3-4x times that number. How? Easy, you jack the gains up. You're not making any more maximum power, eg; the voltage will only go so high, however it will stay at that voltage for a longer duration of time and **** up more current in doing so.

So ya, lower your gains. If you've set your gains with minimal overlap with some equipment to meter clipping you may have something else kinda funky going on. Something as stupid as the chassis of the alternator having a bad ground can cause electrical systems to do some weird things. I'd just make sure you're using the factory ground location on the block.

If you're trying to find the elusive Zero Ohm, well, your amplifier's efficiency goes right into the toilet at normal volumes. The amp will pull a lot more current, thus dropping voltage, and you'll get nowhere near the 80-90% efficiency ratings vendors brag about. That's physics for ya. So if you have a choice to rewire your woofers to 2 ohm instead of 1/2 - do it.

Lastly, have you checked voltage going into the amplifier?

 

[Steveopevo 10+ year member]

Are you running your amp
The other thing is 'RMS'. What the hell does that mean? Honestly, no one really knows as it's a pretty useless number. Average power over a given time is much more useful. With that, your 840w RMS amp may be producing an average power of 3-4x times that number. How? Easy, you jack the gains up. You're not making any more maximum power, eg; the voltage will only go so high, however it will stay at that voltage for a longer duration of time and **** up more current in doing so.

So ya, lower your gains. If you've set your gains with minimal overlap with some equipment to meter clipping you may have something else kinda funky going on. Something as stupid as the chassis of the alternator having a bad ground can cause electrical systems to do some weird things. I'd just make sure you're using the factory ground location on the block.

If you're trying to find the elusive Zero Ohm, well, your amplifier's efficiency goes right into the toilet at normal volumes. The amp will pull a lot more current, thus dropping voltage, and you'll get nowhere near the 80-90% efficiency ratings vendors brag about. That's physics for ya. So if you have a choice to rewire your woofers to 2 ohm instead of 1/2 - do it.

Lastly, have you checked voltage going into the amplifier?

My sub amp is 500 watts operating at 2 ohms, my wiring was done professionally, voltage is 14.2 at amps, and the gain is at 1/3. I thought even with a small amount of clipping it wouldn't have such an impact, obviously wrong. How do you check if your alternator has a a good ground?

 

[KTMrida4life 10+ year member]

My sub amp is 500 watts operating at 2 ohms, my wiring was done professionally, voltage is 14.2 at amps, and the gain is at 1/3. I thought even with a small amount of clipping it wouldn't have such an impact, obviously wrong. How do you check if your alternator has a a good ground?

So you have a 500W sub amp putting out 840W? Thats called clipping, and its also why your voltage drop is so bad. Trust me, I know.... been there done that

Set your gains using a multimeter. Get a multimeter and download a 50hz test track online. Put it on a ipod, cd, or thumb drive. No AUX. Play it at YOUR max volume, not your headunits. Mine is 42/50. Set it to that volume, set the multimeter to ACC and put the positive on the speaker + coming out of the amp and the negative on the -. In your case, you should be seeing 31V. Turn all the bass boosts off, on both the amp and your headunit.

If you dont know how, ask your shop to do it. Ask them to set your gains to 500W using a multimeter or oscilloscope.

 

[Fi_ 10+ year member]

I'm running 840 watts rms, did the big three plus Optima battery and h/o alternator and still getting dimming during heavy bass notes. I did all my upgrades because I'm planning on a bigger system but i'm concerned that with all I've done I'm still dimming. I've read some posts that say some dimming is to be expected due to voltage drops.

Any idea what your voltage drops down to on those heavy notes?

EDIT: NVM 14.2v

 

[Fi_ 10+ year member]

So you have a 500W sub amp putting out 840W? Thats called clipping, and its also why your voltage drop is so bad. Trust me, I know.... been there done that
Set your gains using a multimeter. Get a multimeter and download a 50hz test track online. Put it on a ipod, cd, or thumb drive. No AUX. Play it at YOUR max volume, not your headunits. Mine is 42/50. Set it to that volume, set the multimeter to ACC and put the positive on the speaker + coming out of the amp and the negative on the -. In your case, you should be seeing 31V. Turn all the bass boosts off, on both the amp and your headunit.

If you dont know how, ask your shop to do it. Ask them to set your gains to 500W using a multimeter or oscilloscope.

I'm not arguing that he is most likely clipping but if he is only dropping to 14.2v then that shouldn't be the problem. I run a big III, Big Battery and an efficient amplifier and never drop below 13v and I get some bad dimming others have mentioned it's probably my factory electrical. Could also be a ground or like the other guy said your chassis or alternator ground. Go back over all of your wiring make sure the grounds are good on everything that has a ground.

 

[Steveopevo 10+ year member]

So you have a 500W sub amp putting out 840W? Thats called clipping, and its also why your voltage drop is so bad. Trust me, I know.... been there done that
Set your gains using a multimeter. Get a multimeter and download a 50hz test track online. Put it on a ipod, cd, or thumb drive. No AUX. Play it at YOUR max volume, not your headunits. Mine is 42/50. Set it to that volume, set the multimeter to ACC and put the positive on the speaker + coming out of the amp and the negative on the -. In your case, you should be seeing 31V. Turn all the bass boosts off, on both the amp and your headunit.

If you dont know how, ask your shop to do it. Ask them to set your gains to 500W using a multimeter or oscilloscope.

I have two amps. High amp is 340 rms, sub amp is 500 rms. Alpine type R-12/ mrp-m500. I was told 14.2 while engine running was good. I don't have a multi meter but I've had the gain at 1/4 and still had some dimming. I read a good article stating that some dimming will always occur when your driving your subs hard so maybe nothing to worry about after all.

 

[SPLaudio 5,000+ posts]

something is up unless its a import car then those at idle have such lil voltage...