Amplifier gain settings, rethinking the process..

[gstokes]

Clipping is a serious offense in the car audio community, don't get caught doing it. It's a hot topic and opinions vary but i want to share my thoughts on setting the gain, some people recommend a 75% volume level when setting the gain, that works perfect IF you don't turn the volume up higher than 75%, if you do it's clip city.

Set the gains at the volume level where you listen to the music, if it's WFO like me then turn the volume ALL the way up when setting the gains, if the gains were set at 75% volume now you're listening at 100% volume you are clipping the signal by asking the amplifier for more volume then it was adjusted to provide with a specific voltage, if you want 100% volume then set the gains with the volume at 100%.

That is unless you like listening to your music with the bass and treble turned all the way down, but we need to add some bass and treble soooooooo once you're done setting the gains dial em back just a touch to allow for a generous dose of bass and treble from the tone controls..

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[Syphlyn]

Use an o-scope or DD1 to find the Headunits clipping point and set the gains from there. If you have neither most people suggest 75% on the headunit to avoid clipping entirely because if your headunit sends a clipped signal it doesn't matter whether your amps are at 1% gain or 100% gain it's still clipping.

 

[Umbra]

I think someone needs a Wordpress account.

 

[gstokes]

Use an o-scope or DD1 to find the Headunits clipping point and set the gains from there. If you have neither most people suggest 75% on the headunit to avoid clipping entirely because if your headunit sends a clipped signal it doesn't matter whether your amps are at 1% gain or 100% gain it's still clipping.

very true but most people don't have a o-scope or DD1, i believe that would still hold true for a cheap head unit but modern head units have very low THD even at 100% volume level, for most people you are right though with a 75% volume level being safer for them. I push my system to the edge that much is true, but it has never sounded better..

 

[gstokes]

I think someone needs a Wordpress account.

I love to write, spend too much time on the computer.. SORRY //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[gstokes]

BTW, don't forget to run the engine when setting the gains, you won't see 14.2 with the engine off //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[keep_hope_alive Premium Member]

some modern head units still clip the output, especially if tone controls are used. my Alpine decks have not but I've measured clipping on other brands. it can be affected by the system voltage also.

the problem is worse when people use high level inputs or line output converters. the speaker outputs of head units will clip, and usually just above 75%.

75% volume is a safe level to use and makes sense because recording level varies. some albums (especially before 1990) are recorded quieter and you want some headroom.

the safe way to set gains is to set the input sensitivity to the voltage level of the pre-outs. that's why the units are there. if your amp is cheap and doesn't offer much for labels, then look at the input sensitivity range and assume it's linear.

clipping causes harmonics. if you turn up the high pass filter on the amp and play a low frequency tone, you can measure AC voltage and watch for a jump in level - that will be the point of clipping.

 

[trumpet 5,000+ posts]

Somebody did not watch all of JL Audio School of Sound. Clipping is not a dirty sin, it's necessary to get the full power out of your amplifiers in 99% of systems that average people buy. If you're massively overpowering everything then you need to be more cautious. I own an oscilloscope with a good reference CD, but I don't always get it out to tune a system.

 

[gstokes]

Somebody did not watch all of JL Audio School of Sound. Clipping is not a dirty sin, it's necessary to get the full power out of your amplifiers in 99% of systems that average people buy. If you're massively overpowering everything then you need to be more cautious. I own an oscilloscope with a good reference CD, but I don't always get it out to tune a system.

guilty as charged, i just came back in from setting the gains and mine were turned completely down to 200 millivolts and it was still LOUD, now the gains are set at 36.64V channels 1234 and 31.62V channel 5, it's so frikkin loud that i can't possibly turn it up over level 20 whereas before i was maxing it out at 35.

Here i thought i was pushing the envelope, NOT EVEN CLOSE !!

Now i understand the 75% thing //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[csu87 10+ year member]

guilty as charged, i just came back in from setting the gains and mine were turned completely down to 200 millivolts and it was still LOUD, now the gains are set at 36.64V channels 1234 and 31.62V channel 5, it's so frikkin loud that i can't possibly turn it up over level 20 whereas before i was maxing it out at 35. Here i thought i was pushing the envelope, NOT EVEN CLOSE !!

Now i understand the 75% thing //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

don't think you do but ok.

the reason for 75% is most people that are asking where to set the gain, don't understand that their headunit can clip and at what point it will clip at. The only way to ensure your amp is not clipping is to use an O-Scope or the DD1. Some experienced guys can listen to it and tell you where it is starting to hard clip, but a minor clip is hard to hear.

When I set my gains, I do the ear test 9/10 times. best way to do it outside of an o-scope imo if you know what you are doing, and Im too lazy to hook the scope up most times. The times I do use the scope is when I know my amp is bigger than my speakers and I am going to be pushing the speakers to the limits. Then, a minor clip could cause some issues.

 

[keep_hope_alive Premium Member]

Autosound 2000 Disc 102 has test tones that introduce clipping for a few seconds so you can hear clipping at a known time. helps in determining what clipping sounds like at that moment.

 

[gstokes]

don't think you do but ok.
the reason for 75% is most people that are asking where to set the gain, don't understand that their headunit can clip and at what point it will clip at. The only way to ensure your amp is not clipping is to use an O-Scope or the DD1. Some experienced guys can listen to it and tell you where it is starting to hard clip, but a minor clip is hard to hear.

When I set my gains, I do the ear test 9/10 times. best way to do it outside of an o-scope imo if you know what you are doing, and Im too lazy to hook the scope up most times. The times I do use the scope is when I know my amp is bigger than my speakers and I am going to be pushing the speakers to the limits. Then, a minor clip could cause some issues.

I purchased the PC Based USB Oscilloscope, soon i will better understand what you mean..

 

[T3mpest 10+ year member]

Somebody did not watch all of JL Audio School of Sound. Clipping is not a dirty sin, it's necessary to get the full power out of your amplifiers in 99% of systems that average people buy. If you're massively overpowering everything then you need to be more cautious. I own an oscilloscope with a good reference CD, but I don't always get it out to tune a system.

I've already tried to explain they issues with assuming clipping is a "car audio sin" (it's not) due to many various factors. Inaudibility of minor clipping, lack of thermal stress in many cases if it's managed well and actually getting some real ouptut from your amplifier, he doesn't listen.. Turn the hu to 3/4 turn gains up until you get "good" output from the quieterest speaker you own on most of the music you listen to recorded at normal volume. Turn everythign else up until it blends with that speaker. Gains are an acoustic level matching device they are not built to match input voltage to output voltage blindly ( I guess deafly would be more appropriate here). I mean if your way overpowering speakers you COULD use a device, but even then you can usually hear when things are being stressed. IF your getting noise in your system from bad gain setup, you either REALLY messed up your gain setting or had excessive noise to begin with that needs to be adressed.

 

[LosIsATool 5,000+ posts]

Why does this guy still post stuff? Aiming tweeters straight at your face now this...

 

[csu87 10+ year member]

I've already tried to explain they issues with assuming clipping is a "car audio sin" (it's not) due to many various factors. Inaudibility of minor clipping, lack of thermal stress in many cases if it's managed well and actually getting some real ouptut from your amplifier, he doesn't listen.. Turn the hu to 3/4 turn gains up until you get "good" output from the quieterest speaker you own on most of the music you listen to recorded at normal volume. Turn everythign else up until it blends with that speaker. Gains are an acoustic level matching device they are not built to match input voltage to output voltage blindly ( I guess deafly would be more appropriate here). I mean if your way overpowering speakers you COULD use a device, but even then you can usually hear when things are being stressed. IF your getting noise in your system from bad gain setup, you either REALLY messed up your gain setting or had excessive noise to begin with that needs to be adressed.

He wont listen, sorry you wasted your time typing this.