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How To Tune A Monoblock Amp In 8 Steps: A Noob Mini-Guide

Last Updated on: May 17, 2022

Are you having some trouble with your monoblock amplifier?

That’s totally fine! We all find ourselves struggling with technology every once in a while; especially with devices that require a lot of trials and errors.

But let’s not focus on that…

Let’s focus on the fact that you’re in the right place and we’ll do our best to help you tune that amp!

Keep reading so that we can get started.

The Basics Of An Amplifier

To start, we need to know what an amplifier is. 

When musicians perform instruments on stage, they usually need an external device to amplify the sound so that everyone in a large audience can hear clearly. 

The usage of an amplifier, however, is not limited to musicians. Everyone can be a musician and utilize an amplifier, from DJs to high school students. Some people even have amplifiers in their homes to help them rehearse.

An amplifier is simply a version of a speaker packed with more power. 

An amplifier, like a speaker, has several external knobs and switches that need to be adjusted from time to time to ensure optimal operation and sound quality to prevent distortion.

Monoblock Car Amplifier Tuning Methods

A monoblock car amplifier is a one-channel amplifier. 

A monoblock amp is designed to drive a whole full-range system, not just one speaker or one subwoofer. Only one tweeter, midrange driver, and subwoofer can be used with a monoblock amplifier.

If you have a car amp and you want to make use of its peak worth, then you have to tune it especially if you also have another amplifier for door speakers. There are multiple steps involved for each method but the process is the same. Tuning a car amp may be tricky, but not very difficult.

How To Tune A Monoblock Car Amp Manually

The manual method of tuning an amplifier is said to be the easiest and the most affordable one since it does not require any specialized tools or skills, but only perseverance and diligence to avoid any unnecessary distortion. 

Here are 8 steps on how to tune a monoblock car amp that you can use as a guide:

Step 1: Amp’s Gain Setting

Grab an RTA and adjust the amplifier gain for the subwoofer to get hit with 75% estimated power. 

Do not concern yourself with the loudness as it may become significantly louder in the following steps.

Step 2: Adjust Subsonic Filter

With the use of the RTA, set the filter at approximately 20 Hz. 

Significant energies at a frequency below 20 Hz may still be present, however, this is a significant step to prevent abnormal cone movement.

Allow it to have room for movement to avoid distortion but not to the point that it doesn’t reach its natural resting point.

Step 3: Fine Tune The Subsonic Filter And Phase Adjustment

With your ears and an RTA, select a few frequencies in the 20-30 Hz range that irritate you. 

These may be peaks or nulls. Also, rather than just looking at the frequency response graph, look at the group delay plot. This will help you determine if you’re hearing a peak or a null.

Once you’ve discovered these peaks/nulls, use the filter to drop them down an octave by using negative values (for example, -3 will move it 3 octaves below where it is now). 

You may need to shift the phase of the sub out by +/-180 degrees to get rid of some peaks/nulls in this area.

Step 4: Achieving Maximum Output

Using an RTA, adjust your crossover so that no big peaks or nulls appear between 20 and 80 Hz.

Using your ears and an RTA, set the phase of the subchannel to be as close to the mains as feasible (you shouldn’t notice many peaks or nulls with just bass, but if you do, use no more than +/-180 degrees).

If you can’t make it seem flat and smooth, that’s alright; the idea is to limit the corrective action to a minimum.

Finally, adjust the crossover point on the front channels so that they don’t play anything in the 40-80 Hz zone while playing a track that relies on bass at reference level. This will assist you in maximizing your time.

Step 5: Adjust The EQ

Tune for max output.
Do not pay too much attention to distortion sounds; focus on achieving your goal tune.

Step 6: Fine Tune The EQ

Now, using an RTA and your hearing, remove any peaks or nulls in the 20-70 Hz region by trial and error until it sounds crisp and full. You want it to sound as excellent as possible and free of distortion because this is where the majority of your sound quality originates from.

An imbalanced EQ could result in subwoofer rattling and other noises – something you wouldn’t like to experience while listening to your favorite songs!

Set all the gain control on your amps to just below peaking once you’ve gotten the amp sounding smooth in the low end (this will probably mean turning them down about 20%).

Finally, using an RTA, adjust the crossover on the front speakers such that no frequencies below 40-50 Hz are played. This will increase output while also providing additional headroom for powerful bass transients.

Step 7: Turn Up Playback Volume

The key to avoiding distortion and having decent sound quality from a subwoofer is to make sure it has as few peaks and nulls as possible between 20 and 80 Hz. 

Because EQing out peaks/nulls in this range is considerably easier than EQing out peaks/nulls in the lower frequencies, getting them tuned incorrectly will help you get decent sound quality without spending too much time on EQ.

Once you’ve got everything set up for maximum output, turn up the playback level until it starts to sound bad (you’ll hear bass clipping), then turn it down till it sounds good again. 

Any peaks or nulls that appear now will be louder than before, so either re-run your RTA or double-check your car amplifier settings or leave it alone.

This is to keep the sub sounding as good as possible while reducing bass clipping and distortion.

Now, using an RTA and your ears, adjust the sound quality by removing any peaks/nulls in the 20-70hz area to remove distortion and make it sound as smooth as possible. Instead of boosting certain frequencies, this usually entails EQing away a lot of nulls.

Once you’ve got the EQ looking good, bump up the playback volume until it starts to sound bad (bass clipping), then turn it down until it sounds good again. 

Peaks and nulls that appear in the sound quality tuning stage will be stronger than previously, so either re-run your RTA or double-check your EQ settings or leave it as it is.

Step 8: Test Drive

You can now give it a try. 

From here, to ensure the sound and music that you listen to, tweaking the car audio system is recommended for you to avoid distortion as well.

It is recommended to install second battery for car audio. This will act as your monoblock amp’s source of power and free up your primary battery to take care of your car’s other functions.

Headbanging dudes

How To Set Up Monoblock Amplifiers With A Multimeter

This alternative procedure is sure to be of help if you cannot grasp the manual method.

  1. Use the digital multimeter to measure the speaker’s hindrance
  2. Disconnect the speaker’s power supply wire
  3. Determine the positive and negative station
  4. Connect the black probe to the negative terminal and the red probe to the positive of the digital multimeter
  5. Read and record the impedance (Ohms) portrayed in the multimeter
  6. Compare the recommended wattage output of the amplifier to the impedance
    1. Look for the user manual for more information
    2. Compare and contrast figures against recorded speaker resistance
  7. Look for the target AC voltage
    1. V = √ ( Wattage × Speaker Impedance)
  8. Calculate
  9. Unplug all accessories
  10. Turn off equalizer
  11. Set amp gain to zero
  12. Set the maximum volume of the head unit to 80%
  13. Play a 60 Hz test tone CD
  14. Securely plug the RCA cable back
  15. Enjoy quality car audio

How To Tune A Subwoofer Amp

  1. Reduce the volume of the head unit to the lowest setting. Make sure it’s not muted because you’ll need to hear how the subwoofer amplifier sounds while tuning to make the exact adjustment.
  2. If there is a bass boost option, turn it off or remove it.
  3. Set your low pass filter to a frequency range of 100-140 Hz.
  4. Reduce the subwoofer amp’s volume to the bare minimum.
  5. Now gently and steadily increase the amp’s level to the loudest it can go without causing distortion.
  6. Set the amp’s level to the maximum level at which you achieve the required output.
  7. If you want to add a bass boost to the sub amp’s sound then, you can do it by adjusting the bass on the deck unit. A bass boost is ideal because it equalizes the sound and enhances low frequencies.

Frequently Asked Questions

What LPF should be set on an amplifier?

With only one amplifier receiving a signal from your head unit, you can play car audio of your choice at 75% volume at most with the LPF filter on your amp set to its maximum position. Adjust the frequency until you no longer hear of high frequencies from the subwoofers.

What Hz is best for bass?

A 20-120 Hz rating is the recommended option. The lower the Hz, the deeper the bass is. Some quality subwoofers have this Hz range. I recommend a subwoofer with below 80 Hz if you’re a bass type of a person.

What is the purpose of subsonic on an amplifier?

This helps you reduce the intensity of car audio that is at low frequency. Moreover, it decreases the amplitude of low notes that you feel more than you hear.


Conclusion

Now that you know not only how to tune a monoblock amp but also how to set up monoblock amplifiers with the use of various methods, choose what you think suits your situation best. 

Remember that regularly tuning the amp will ensure that it generates high-quality sound. Failing in not tuning it, on the other hand, would result in poor sound quality, distortion, and inefficient use of the amp’s capabilities. 

Whatever the case may be, remember to treat your musical instruments and accessories with care. If you find yourself confused in tuning any of your instruments, feel free to do research on the internet or ask for professional help.

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