# Amplifier Gain settings (without a dmm)



## getonerd

Quick Amplifier Tuning for Dummies. Well not really, but this is a quick and easy way to tune and calibrate your car amplifiers. 
Once you have all your speakers, amps, radio, and whatever else installed, set your equalizer to flat. This will be different on different radios, but basically you want the Bass, Mid, and Treble levels set at 0. 
Files

First you need to download these two mp3 files and burn them onto CD. (MP3 or regular audio will work) There is a 60Hz and a 1000HZ file. The 60HZ file will be used to tune your subwoofer amp. The 1000Hz file will be used to tune your mids/highs. 
•	60Hz (for bass) if u need test tones get it here
•	1000Hz file in next post (for mids/highs)
Radio Calibration


Let's start with radio / head unit level adjustment. Turn the Gain on the Mids/Highs Amp almost all the way down (~1/4). Set your amp OR head unit output to high-pass filter which will filter off any subwoofer signals so you do not have bass going to your regular mids/highs (Ignore this if you do not have a subwoofer installed!!!) Unplug your subwoofer amp (or turn it off). 
Load in the CD that you burned with the two test-tone files. Play the high pitched tone (1000hz) and begin increasing the volume on the head unit steadily. At some point you will hear it "clip". This will be a noticeable difference in the sound of the tone (the pitch will change). Once you have found the point where you hear the clipping, turn the radio down 2 notches and leave it at this level. Now pause the CD. This is the maximum level your radio will output without distortion. It will vary from radio to radio. Some brands have very bad output and will begin clipping very early, while others may not clip until the very end (if at all). 

Mids/Highs Amp Adjustment


now let us move on to the Mids/Highs Amplifier. Since we already know where the head unit clips, this part is easy. Make sure the head unit is still at the previous max level we found earlier. You may need some ear plugs for this one because it is going to get loud (especially if you are pumping some mean juice into those speakers ) Make sure you have quick access to the Amp's Gain (or level) adjustment. Play the high pitch tone (1000hz) again, but this time begin increasing the Amp's Gain. Increase it until you hear the same "clipping" or tone change you heard earlier. Now turn the amp level down just slightly under the clipping level. Done! Pause the CD (unless you want to go deaf). Your Mids/Highs Amplifier is now calibrated to your head unit. 

Subwoofer Amp


Now to shake the house and piss off the neighbors.. The subwoofer amp! Make sure you turn the sub amp on and the mids/high amp off (or unplug the RCA cables). Just as we did before, turn the Amplifier Gain almost all the way down. Turn the bass boost down to 0 (both on the head unit and the subwoofer amp. You should also turn on a low pass filter either on the head unit or on the Subwoofer Amp so that you get only bass tones going to your subwoofers. Make sure you can easily access the subwoofer amp's Gain level quickly. Turn on the low pitched tone (60hz) on the CD. Begin steadily increasing the Amplifier Gain until you audibly hear distortion and/or a tone change. There are two things going on here: A) your amp will be strong than your subs and will cause the speaker to over extend. (Distortion) B) Your subs are stronger than your amplifier and the amp will clip way before any damage to your subs will occur (tone change). 
If you do hear distortion do not exceed that level or your speakers will blow. You have now found the optimal subwoofer level for your system. Eject the CD and apologize to anyone you woke up in the neighborhood. 


Finishing Up


Make sure you hook everything back up and turn your head unit back down to a normal level. Now each of your stereo components is calibrated to each other. Go ahead and listen to your favorite music and tweak the head unit settings to your taste. If you want a little extra thump, increase the bass boost on the subwoofer amp slightly. Again this is a way of calibrating your system to reproduce music as it was recorded! Some people enjoy hearing nothing but bass so they should not follow this guide and just crank up the bass boost to +100. Everyone will look at them like they are idiots, but that’s ok because that is how they enjoy music.


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## t3sn4f2

DON'T USE THE TONES FROM THAT SITE!

I run the 1000Hz mp3 tone from the link directly without downloading and it totally screwed my EMU mixer and killed my sound. I had to restore XP back to a few days before to get my sound output back.

Not only that but the tone is not full scale, it's around -3dB. So if you use it to set gains, you will set everything to half the power your amp can put out and then you will over driver it when a true full scale music peak hits.


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## sam3535

IMO, much better tutorial to non dmm gain setting here: http://www.diymobileaudio.com/forum...orial-gain-setting-amplifier-power-usage.html


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## Austin

Or just get the test tones from the download section on this site:

http://www.diymobileaudio.com/index.php?pageid=audio_downloads


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## kyheng

Best is use your own ears to set gain and test.....


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## sam3535

kyheng said:


> Best is use your own ears to set gain and test.....


That is what the OP's post is about and the tutorial I linked to.


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## biig o

is using DMM better?


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## chad

biig o said:


> is using DMM better?


for many things other than setting gain


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