Amplifier Setting Tutorial
Outline:
Setting up an amplifier can be a very confusing and intimidating process for newbies. I created this to help guide those people through the process in what I consider to be a simple and easy way.
Preparation:
Things you should do and will need:
1) Read the owner’s manual(s)
2) Familiarize yourself with your equipment
3) Determine the final load of your speaker(s)/sub(s)
4) A calculator
5) A digital multimeter
6) A test tone CD
7) A print-out of this guide
A pen or pencil
9) A notepad
Note: All tests should be done with the engine running while using the calculation methods, at least for the part where you’re measuring.
Step 1: Setting up your head unit
1) Turn off all filters (low-pass and high-pass)
2) Set your EQ settings to 0 (i.e. Bass, Treble, Mid)
3) Turn off loudness
4) If you won’t be using the head unit’s internal amp, turn it off (if possible)
Step 2: Choosing the test tones you’ll use
Tones can be found here:
http://www.caraudio.com/forum/showthread.php?t=164136
I’ve provided 4 different sets of tones and I’ll give a brief description of why one would use that particular set of tones.
0 dB:
Pros – No chance of clipping, very small chance of damaging equipment
Cons – Most music won’t reach 0 dB unless you’re running full range speakers, so you probably won’t get full performance
-3 dB:
Pros – Small chance of clipping with music in subs, small chance of damaging equipment, better performance than 0 dB
Cons – Small amount of clipping on peaks with some music (speakers)
-6 dB:
Pros – Better performance than -3 dB and 0 dB
Cons – User must be able to detect stress in equipment to prevent damage, moderate amount of clipping with some music (speakers), small amount of clipping with some music (subs)
-10 dB:
Not recommended for amateurs
As implied in the above descriptions, the choice of music you listen to may influence the tones you use as well. With pretty much all genres, I found that the mids had peaks above -1 dB, so I wouldn’t recommend that newbies use anything higher than -3 dB for setting the speaker amplifier. However, bass (20 Hz - 80 Hz), is a completely different story. I’ve analyzed a few dozen different songs from a variety of genres with Adobe Audition and here are some briefs descriptions.
Rap/Hip-Hop/Pop – Most of the songs in these genres had peaks in the -9 dB to -3 dB range. I recommend using 0 dB or -3 dB tones if you primarily listen to these genres.
Rock/Metal/Jazz/Classical – Most of the songs in this genre had peaks in the -12 to -6 dB range. I recommend using 0 dB, -3 dB, or -6 dB tones if you primarily listen to these genres.
After choosing the tones, download them and burn them to a CD.
Step 3: Setting up your speakers
If using the head unit’s internal amplifier:
Method 1: By ear
1) Using music you’re familiar with, turn up the volume until you begin to notice distortion or you achieve the desired volume (whichever comes first)
2) Write down the volume
3) Change music to a bass heavy track and set to repeat (if your HU has no HPF, disregard this and the following)
4) Turn on the high-pass filter and set to the highest frequency
5) Turn up the volume to the volume written in Step 2
6) Turn down the HPF frequency until you begin to notice audible distortion
7) Use the lowest HPF frequency with no distortion
Turn the volume down to 0 and turn off head unit
Method 2: Calculation
1) Open your owner’s manuals and find the RMS power output of your head unit’s internal amplifier and the rated RMS input for your speakers. Write down both and use the lower of the two in the next step.
2) Calculate the desired voltage using the formula: Voltage = SQRT(Power*Resistance)
3) Write down the desired voltage
4) Set the volume to 0 and turn off the head unit
5) Unhook one of the speakers
6) Attach the leads of the multimeter to the speaker wires (do not ground speaker wires or leads)
7) Set multimeter to measure AC voltage
Turn on the head unit
9) Adjust the balance and fade to only the speaker that is unhooked (i.e. If using front right speaker, balance to the right and fade to the front)
10) Insert the test tone CD
11) Fast forward to the 1000 Hz track and set to repeat track
12) Turn volume up until you achieve the desired voltage
13) Write down the volume
14) Turn the volume down to 0 and shut the head unit off
15) Unhook the leads from the speaker wires
16) Hook the speaker back up and remount
17) Turn the head unit back on (if your HU has no HPF, disregard this and the following)
18) Insert a bass heavy track and set to repeat
19) Turn on the high-pass filter and set to the highest frequency
20) Turn up the volume to the volume written in Step 13
21) Turn down the HPF frequency until you begin to notice audible distortion
22) Use the lowest HPF frequency with no distortion
23) Turn the volume down to 0 and turn off head unit
24) In the future, do not exceed the volume written in step 13
If using dedicated speaker amplifier:
Method 1: By ear
1) Turn the gain/sensitivity all the way down (counter-clockwise)
2) Turn head unit on
3) Insert music you’re familiar with
4) Turn volume up to maximum volume you will normally use or 80% of maximum volume
5) Turn the gain up until you reach the desired volume or you notice audible distortion
6) Turn the volume down
7) Turn the high-pass filter on. If your HU and amp both have HPFs, use the one with the most flexibility (continuously variable > selectable > fixed) (if your head unit and amplifier have no HPF, disregard this and the following)
Turn the HPF up to the highest frequency
9) Insert a bass heavy track and set to repeat
10) Turn the volume up to the volume written in Step 9
11) Turn down the HPF frequency until you begin to notice audible distortion
12) Use the lowest frequency with no audible distortion
13) Turn the volume down to 0 and turn off the head unit
Method 2: Calculation
1) Open your owner’s manuals and find the RMS power output of your amplifier and the rated RMS input of your speakers. Write down both and use the lower of the two in the next step.
2) Calculate the desired voltage using the formula: Voltage = SQRT(Power*Resistance)
3) Write down the desired voltage
4) Turn the gain/sensitivity all the way down (counter-clockwise)
5) Unhook all speakers from the amplifier (unhook at the amplifier, not at the speakers)
6) Insert leads of multimeter into one of the channels and tighten slightly
7) Set multimeter to measure AC voltage
Turn head unit on
9) Insert test tone CD
10) Set track to 1000 Hz and set to repeat
11) Turn volume up to maximum volume you will normally use or 80% of maximum volume
12) Write down the volume
13) Slowly turn the gain up until you reach the desired voltage
14) Turn the volume down to 0 and turn off head unit
15) Remove multimeter leads from the amplifier
16) Hook speakers back up to the amplifier
17) Turn head unit on (if your head unit and amplifier have no HPF, disregard this and the following)
18) Turn the high-pass filter on. If your HU and amp both have HPFs, use the one with the most flexibility (continuously variable > selectable > fixed)
19) Turn the HPF up to the highest frequency
20) Insert a bass heavy track and set to repeat track
21) Turn the volume up to the volume written in Step 12
22) Turn down the HPF frequency until you begin to notice audible distortion
23) Use the lowest frequency with no audible distortion
24) Turn the volume down to 0 and turn off the head unit
25) In the future, do not exceed the volume written in Step 12
Step 4: Setting up the subwoofer(s)
Setting the gain/input sensitivity:
1) Open your owner’s manuals and find the RMS power output of your amplifier and the rated RMS input of your speakers. Write down both and use the lower of the two in the next step.
2) Calculate the desired voltage using the formula: Voltage = SQRT(Power*Resistance)
3) Write down the Sub Voltage
4) Turn the gain/sensitivity all the way down (counter-clockwise)
5) Unhook all subwoofers from the amplifier (unhook at the amplifier)
6) Insert leads of multimeter into one of the channels you’ll be using (if you’re bridging the amplifier, use the terminals you’ll be using)
7) Set multimeter to measure AC voltage
Unhook the speakers from the speaker amplifier or turn off the amplifier’s internal amplifier
9) Turn head unit on
10) Insert test tone CD
11) Set track to 60 Hz and set to repeat track
12) Set to the volume written down in the speaker setting stage
13) Slowly turn the gain up until you obtain the desired voltage
14) Turn the volume down to 0
Setting the subsonic filter (if available):
1) Determine the tuning frequency of your enclosure (if using a sealed enclosure, turn SSF off or to minimum frequency)
2) Calculate the desired SSF frequency by using the formula: SSF = Tuning*3/4
3) If number is not whole, round to the nearest integer
4) Write the SSF frequency down
5) Calculate the desired SSF voltage by using the formula: SSF_Voltage = 0.707*Sub_Voltage
6) Write the SSF voltage down
7) Turn the SSF to the maximum frequency
Set track to the SSF frequency and set to repeat track
9) Set to volume written down in speaker setting stage
10) Turn down the frequency on the SSF control until you reach the SSF Voltage from step 6
11) Turn the volume down to 0
Setting the low-pass filter:
1) Turn off the head unit
2) Unhook the multimeter from the sub amp
3) Hook up the speakers and sub(s)
4) Turn the low-pass filter on. If your HU and amp both have LPFs, use the one with the most flexibility (continuously variable > selectable > fixed)
5) Turn the LPF frequency to the minimum frequency
6) Insert music you’re familiar with
7) Turn the volume up to a comfortable level
Turn up the LPF frequency until one of the following is true: the sub stage and speaker stage blend perfectly, you can tell the bass is coming from the rear, or the bass starts sounding weird. If the latter two, use the highest setting before audible anomaly.
9) Turn volume down to 0 and turn off head unit
Level matching:
Use your head unit controls to attenuate parts that overpower the rest of the system
