has anyone tried setting their gains by using a multimeter. Theres instruction on jlaudios website:

http://mobile.jlaudio.com/support_pages.php?page_id=143

I got the test tones from:

http://realmofexcursion.com/

(50 hz and 1khz) for the front speaker amp and sub amp

Im trying to figure out if I should set the multimeter to read AC or DC voltage. anyone know?

I have a feeling from the tutorial that its AC but I want to be sure before I go blowing things up!

Thanks

 

You set it for AC. From looking at this site it seems to show you how to adjust gains using a multimeter, but it is not really the correct way to do it. The correct way to do it would also be using a scope to determine the clipping point of the headunit. Not all headunits clip at the same point. They seem to tell you to turn the headunit 3/4 of the volume, but some head units clip before that and some don't clip at all, even at full volume. The way they are showing you is kind of a shortcut method.

 

is there a way short of a scope to find that clipping point?

will this way at least get me close?

 

it will get you close. this is usually considered a good way, emphasis on good not great, way for the avg person to set their gains. from what i understand oscilloscopes are pretty expensive and not that common. if you have access to one or are willing to spend the money on one then go for it. if not, using a multimeter should be fine. however if you do it that way and it sounds like distortion is occuring, then bring the gains down til you hear it go away.

 

would it make sense to use the instructions at the bottom of this post:

https://my350z.com/forum/showthread....ight=test+tone

to find the clip point of the headunit and then use a meter to set the gain on the amp or are these two completly different methods? Prob going to set it up tonight

also before i start should i reset all the settings so that nothing is "on" ie tur the Eq off the sub down to 0 on the headunit or should i have it setup as i normally would (bass and treble set etc) and then go through the steps. ive read both ways just wondering what will give me better results

thanks again

 

Using an ocilloscope to find clipping isn' that hard. You play back a test tone - the pure tone makes seeing the clipping possible - and increase the output amplitude until you see the peaks of the waveform distort - typically they'll flatten out and start to form square waves.

Clipping destorys speakers and the music. I often hear people enjoying music with 3% or higher clipping. I look at them and ask them if they can't hear the massive distortion going on ... and I get this look: their hearing is so bad, destroyed from excessive volumes that they can't even hear the speakers crying out in pain.

 

i realize that using a scope os the best way to go but i dont have access to one! I wish i did but in place of using a scope i was just wondering if using the above technique would work...ie playing a tone with the gains down and turning the headunit up until it clips then turning it down a few clicks and then using a multimeter to set the gain on the amp.