Amplifier Tuning Guide (the basics) by StereoInstaller1

7 minute read

Amplifier Tuning Guide (the basics) 

Compliments of StereoInstaller1 @ r3vlimited.com

4-12-2013

Quick tuning guide

I.Introduction

1. Preparation!

a. Expect to play your stereo very loud for an hour.
b. Make sure you have either the ability to run the motor or have an adequate battery charger connected.
c. Make sure you can get to all the controls and won't annoy anyone with your loud stereo. This is a simple but critical part of the installation.

2. Make sure all of your speakers are properly assigned (left and right, front and rear) and everything is working properly.

If you are not sure it is installed properly, don't waste your time reading this, get it all working properly first. Make sure all of your speakers are in phase, make sure everything works as it should.

II.Settings and Reference Volume

1. Set your deck "Flat". 

a. Turn off all "enhancements" your deck may have. Make sure bass and treble are at 0, and loudness or any other form of bass boost is off. Yes, I can explain why, but just do it. Tweak on it later, after tuning.

2. Reference volume. 

The idea here is to get all the clean signal voltage your deck has. Your stereo will sound better if you pump more volume in to your amps and leave the gains low, than if you were to pump only mid-volume to the amps and try and compensate with more gain.

a. First turn all the gains on your amp (s) down to zero. While you are looking at it, look for "EQ" or "BASS BOOST" and turn them off completely. Make sure your subwoofer is completely off at this point too. For this stage, make sure all the active crossovers everywhere are off, both in the deck and on the amp.

b. Now, play a nice sounding modern recording with a full range sound. Maroon 5 or JayZ, whatever, but something that is balanced and full range, not just boom. Female vocal is perfect.

Your gains are still all at zero. You should (depending on your amp) hear nothing. Or if you do hear something, it should be quiet/faint.

c. Turn up your deck to full volume. Then begin to turn up the Front Gain until you hear distortion. The volume on the deck should be 100% max, but since you have the gains low, it should sound clear.

This point here is important: Listen for clarity. If it is not completely clear, turn the gain down until all traces of obvious distortion go away. To double-check, bring the amp gain up just a bit and re-create the distortion before lowering it again.

d. Now repeat step “c” above for the rear speakers, making sure to do it with the front gain turned down as low as possible (but remember where you set it!)
Now that volume setting on the deck is your "reference" point. You will do all high volume tuning at that setting, so make sure you know it.

Now we can begin adjusting crossovers and fine-tuning gains!

III. Bring in the fronts! 

At this point, your deck should be playing at your "reference" volume point and your front/rear gains should be where you left off in step 2c and 2d. Your subwoofer should still be OFF.

1. Create distortion

a. First, turn the gain on the rear speakers all the way down. Next, bring up the gain on the fronts until you hear obvious distortion from your front speakers...don't try to destroy them, just a bit of "fuzzy" sound.

b. Now, turn on your high pass filters. You can do this in the deck (2nd choice) or on your amplifier (ideal in most cases) but set it to roughly 100Hz. Once you turn on the high pass, what little bass that speaker made should be gone and the sound should be clean and clear.

You will find that the higher the high pass frequency, the less distortion, but also the "tinnier" it will sound. The goal is to have as much "meat" to the sound without obvious distortion.

c. Take some time now to play with it, adjusting the high pass and the gains until you have achieved an ideal compromise.

So, at this point you should have your front speakers just blasting with zero bass, but nice and clean.

IV. Bring in the rears! 


1. Set the high pass on the rears to roughly 100Hz and raise the gains. You should be able to sit in the front seat and just hear the rears, the brunt of the music should be in front of you.

The goal here is to get an appropriate balance of sound from the front and the rears. That balance is 100% personal preference, make yourself happy here.

2. Now that you have a proper front/rear balance of sound, it’s time to do the same series of adjustments to the rear high pass that you did to the front high pass (See step III.1, but do the rears with the front gains turned down so the rears can be heard more clearly). See how much "meat" you can get out of them. All of these adjustments will likely be "fine tuned" once you have everything working together.

And now, let’s get some serious sound in this car, right?

V.Bring on the bass!

Before we turn the subwoofer on, let’s re-check. We know how loud we should have the volume, we know we should have our mids and highs are nicely balanced front to rear and play very clearly.

1. So, set your low pass filter to roughly 80Hz and turn up the gain!

What you will find is that the lower crossover point you use, the more the bass seems to come from the front, which is one of the main goals of quality car audio. If you choose a bigger "boom" you will find a lower setting might be preferable, all of this is basically personal preference. 80Hz is only a good basic starting point!

2. Your amp may be equipped with a "subsonic" filter. If it is, you should set it as low as you can, but do remember you will get more power handling if you set it higher. Typically, I set these to roughly 25Hz for a 10" or 20Hz for a 12"...again, this is all personal preference.

3.If you find your bass downs out your mid and highs, turn it down! If you find your mids and highs drown out the subwoofer, turn them down, but again, aim for that natural front/rear balance and don't forget how your highpass filters work, make it all "blend" nice and smooth.

VI. Fine Tuning

1. At this point your "reference volume" should be very loud, if not absolutely stupid loud. Try different musics, test tones (a "20Khz to 20Hz sweep" is fun, but play it quietly!) and don't be afraid to tweak things as needed. You will find that when everything is properly adjusted, your system can play anything from Mozart to Metallica, Jazz, blues, whatever.

2. So, now that you have a nice, natural, clean sounding system, go ahead and play with the EQ settings, bass, treble, whatever. Be gentle, adjust in small increments as all of these adjustments can play havoc with power handling... and please try to not use any EQ in the bass at all, vented boxes do their own "bass boost" and you can easily overheat your amp or your woofer...don't blow it up!

Good luck and happy tuning!

Luke