How To Setup Car Audio 7 Band EQ Using RTA

Some simple audio improvement are actually free. This applied to all audio system, not only at home, but also in the car. For instance, the car audio by nature has all audio feature on the head-unit itself to tuning the sound as we like to hear. The most cases, we are using it to improve the bass and treble based on what we think it is makes sound better. But mostly it turn out to become an awful sound quality. In this post, I will share some tips to make an adjustment on your car head unit EQ properly. It is more likely professional approach that you will find in audio workshop and it is not only makes the EQ setting close to match with the car environment, but it rewarded with better sound as well.

Before begin this setting, let me first explain all supporting equipment to make this setting rewarding, and here they are:

1. Car radio or the head-unit that capable to setting the EQ. The more number of EQ would be better.

2. Speakers upgrade to the wider frequency response with all supporting mounting.

3. A smartphone and RTA Apps.

4. Pink Noise sound generator or similar with the track-21 on EMMA SQ Competition disc.

5. This article explanation.

6. Time and patience.

In my example, I will show my EQ setting on my daily car. This is 2017 Honda Brio, a small car for Asia market. It is very comfortable to drive. It has modern design inside-out with moderate 100 horsepower for city cruising. Quite okay didn't it?! For sure I have replaced the factory radio or I often call it the head-unit several times. You can find my post here when I am using Sony single disc head unit, then replace to more suitable to the car dash-board with Pioneer AVH-G115DVD. You also can find my post about it here. You can see from the photo that this Pioneer is perfectly match to the car interior. It is flush to the dash-board panel and I don't have any complain about this matching. Sound wise? It is not better than Sony head-unit before and that is why this EQ setting come in place to fix the sound issue.

Note to be taken that the more EQ setting you had on the car head-unit, the more flexible you can adjust the EQ to the desired frequency response. Most of OEM car radio has only 2 band EQ, you will know it by the BASS and TREABLE setting. This will give limitation for you to adjust individual EQ for sure. My Pioneer above has 7 EQ setting which also very limited but still after the adjustment it works well than factory EQ presets. You can also install external device like DSP or amplifier, but on my case, I only using as minimal as I can to approach better sound. Until today, I am not yet install any external amplifier in my car. I has very clean setting by using only the head-unit and speakers. You can see my cable socket from factory socket head-unit to the Pioneer is using the after market socket. I made it very clean connection and it just like a factory cable socket adapter. It is hassle free for sure and I love it.

The most important aspect besides the head-unit EQ numbers is the speakers that you are using. Most factory speakers are junk. Especially for the car like this, you cannot expecting to get the better sound from it. I suggest you to replace them right away, but in correct approach. Tips for finding the speakers for factory replacement is not aim for higher wattage. Because we are only using the amplifier from the built-in head-unit, so nominal 20 watt speakers is very sufficient. Mostly aftermarket speaker for car has information about this direct factory speaker replacement. Means it is more flexible to use in any car with the nominal wattage match to the head-unit. In my case I find the JBL GT7 is very suitable.

It is a coaxial speaker design and if you like the split speakers, which this JBL GT7 also have, means the tweeter can be mounting higher than the mid-range speakers then it is also better in terms of sound imaging. The main reason I choose this coaxial speakers is because it is very simple. It is direct replacement to the factory cable, no need for me to re-route the extra cables for the separate tweeter.

By using the after-market speakers means you also have to buy the speakers mounting adapter. The more popular cars has many option to choose for this accessories. Same like this Honda Brio which I didn't have difficulty to find it anyway. This speaker mounting adapter not only to make the installation easy and clean look, but it replicate the factory speaker mounting to adapt with after-market speakers. Also I using the O-ring foam to close the gap between speakers and the door trim. This makes the sound wave more direct and efficient to the listener. Simple words, the bass response more tight and the mid frequency more sound lively. Anyway, I only replace the front speakers and leave the rear speakers factory removed. It back to your own preference, but my approach to using only the front speakers is to create more focused center imaging. For sure you can approach this method without remove the rear speakers by only using the FADER adjustment in the head-unit by fully push it to the front and let the rear speaker mute.

Others initial setting on the car head unit are should be in FLAT mode. Means all EQ or BASS and TREBLE in the '0' level. No LOUDNESS setting activate, no others sound mode activate as well. So, after confirm all above setting on the head-unit that you are using, also the speakers that capable to produce wider audio frequency than the factory one, then here we are now ready to setting the EQ.

We need proper tools to measure the audio frequency response produce by the speakers that we want to measure. I am using iPhone 11 because it is the best hardware I can find. I used to have Samsung Galaxy Fold before and other brands as well, still the hardware is not better than the iPhone. In this case, the sensitive microphone is very essential. No discussion about this, it is magnet for fanboy out there:)

The App to run the audio measurement is Real Time Audio Analyzer, in short we call it RTA. There is many RTA Apps but I can suggest you to try the Audio-control RTA for free. This App not only measure the audio frequency in 1/3 octave, means it has 30 band frequency to measure, but it also has the speakers polarity check. I think this will be discussed separately, but I suggest you to have proper polarity speaker cables installation, means the speaker positive wire from the head-unit goes to positive terminal on the speaker as well, vice versa with the negative wire. In short all speaker wiring should give the speakers in the positive phase. Otherwise this EQ setting would never be set correctly.

Are you still with me? or it is already confusing? Ok good then, I continue.

Then run your car engine and park it in the safe place, turn on the aircon so you can relax for a while. Take your EMMA SQ Audio CD, buy it first if you don't have one or you can use any pink-noise from others source. This EMMA CD has this pink noise for about 5 minute on track-21. I turn the ON the Repeat setting so I can focus on the graph frequency response on the RTA while I adjust the EQ band on the car head-unit one by one.

The RTA is simply pick the pink-noise sound from the speakers to the microphone on the smartphone. Normal sound level to be measure is about 60 up to 70 decibel. In my head-unit volume level, it is mark 22 on the volume level when doing this test. The maximum volume is 50 and mostly I listen music from 11 up to 19 in volume level. The perfect RTA graph is aim for the most flat graphics as you can. You will see from the first time the sound and RTA running, the graph is far from flat. From the EQ setting on the head-unit, try to toggle one by one the EQ frequency and find the changes on the RTA display. Adjust it until you get the best possible flat audio response read by the RTA. That is why the more number EQ setting on the head-unit will give the more flat response on the RTA.

And this is the best audio frequency response that I can achieved with the Pioneer 7 band EQ setting. Not the prettiest response by the way. There are also much peaks and dips on the graph that you cannot fix by this small amount EQ number for sure. I also spending about an hour to get this setting by back and forth testing between the pink-noise and the real music playing. Then I adjust it again to make it better and better. This approach is needed and time consuming for sure. If we set the EQ based on the RTA display only, you will find that mostly on lower frequency or bass response is not audible enough when playing you favorite music.

You might want to test this new EQ setting to the real driving environment. Which more likely there will be a minor changes on the EQ setting based on listener preference rather on the RTA. In my experience with this setting, because the engine and tire noise are in between the bass and mid-range, so I should turn ON the loudness of this Pioneer at the Low setting. This Loudness setting in Pioneer HU has 3 different option which the Low is suits to me. It boost the bass up while there is audibly no changes for mid and treble frequency response.

So after all steps explained above, the sound quality right now is far better than before. Sound more airy, more fuller and staging is simply wider compare before the setting or using presets EQ. It is very rewarding sound result and more over, this is the correct and free approach for best setting possible you can get from simple car audio setup like this.

Disclaimer: Any statement and photos in this article are not allowed to copy or publish without written permission from the writer. Any injury or loss from following tips in this article is not under writer responsibility.