Equalization: A Primer
So, we've gone over the basics of DSP. So far we've covered time alignment and level matching to help you tune. Another major aspect of tuning is using the EQ to help resolve problems. Now, some may say EQ isn't necessary. I say that depends: what is your goal? What do you want to achieve in a car? What speakers do you have, how is your install set up, did you pay attention to the driver basics section and how it impacts your crossover choice?
Let's put it this way:
If you have a speaker that has few problems outside of it's beaming point then you're ahead of the game. If you cross the speaker before modal issues take over then that's a help. If you aren't doing either of these then you need to know that the speaker is going to cause you all sorts of problems and you're going to be going hard to work on the EQ to correct these problems. Compounding it more is the simple fact that some problems can't be resolved via EQ. You can't fix a cancellation null in a speaker due to surround or basket resonance. Not going to happen. You can't fix a modal issue in one axis and it not affect other axes. What about your installation... do you have resonance in an enclosure? If so, good luck correcting for that with standard 1/3 octave EQ.
But, let's say you've got the system set up to the best of your ability (install and basic tuning methods already discussed). When it comes to using your DSP’s equalizer, there are essentially two different methods you can use:
Each of these methods has some advantage over another, but there is no single ‘best’. What I find is a good mix of ear and measurement will net you the best response.
"Why can't I use just one of these methods?"
"Why not just use method only? "
Because of the human factor: We don’t always understand what the data is showing us and misinterpret it, therefore creating more problems than we set out to fix.
So, we've gone over the basics of DSP. So far we've covered time alignment and level matching to help you tune. Another major aspect of tuning is using the EQ to help resolve problems. Now, some may say EQ isn't necessary. I say that depends: what is your goal? What do you want to achieve in a car? What speakers do you have, how is your install set up, did you pay attention to the driver basics section and how it impacts your crossover choice?
Let's put it this way:
If you have a speaker that has few problems outside of it's beaming point then you're ahead of the game. If you cross the speaker before modal issues take over then that's a help. If you aren't doing either of these then you need to know that the speaker is going to cause you all sorts of problems and you're going to be going hard to work on the EQ to correct these problems. Compounding it more is the simple fact that some problems can't be resolved via EQ. You can't fix a cancellation null in a speaker due to surround or basket resonance. Not going to happen. You can't fix a modal issue in one axis and it not affect other axes. What about your installation... do you have resonance in an enclosure? If so, good luck correcting for that with standard 1/3 octave EQ.
But, let's say you've got the system set up to the best of your ability (install and basic tuning methods already discussed). When it comes to using your DSP’s equalizer, there are essentially two different methods you can use:
- Ear
- Correlated Pink Noise or 1/3 Octave Pink Noise: these tracks can be used for tonality adjustments and centering of frequencies that may jump out of band
- Measurement
- SPL Meter used with 1/3 Octave Pink Noise or tones
- RTA
- Impulse
Each of these methods has some advantage over another, but there is no single ‘best’. What I find is a good mix of ear and measurement will net you the best response.
"Why can't I use just one of these methods?"
"Why not just use method only? "
Because of the human factor: We don’t always understand what the data is showing us and misinterpret it, therefore creating more problems than we set out to fix.
- "Measurements don’t lie, right?"
- Well… sure, they tell you what they tell you. But what if you are measuring the wrong way? Doesn’t help you, does it? There are numerous tutorials on how to measure yet there’s still a lot of questions and potential for better ways to measure. Additionally, you may want to believe you fixed a problem because it’s visually not there, but what if you fixed the wrong thing? What if the bump at 1khz you knocked down was merely next to a null that can’t be fixed? So, you knocked down 1khz 9dB and you thought you fixed it only to sometime later realize you didn’t fix the real problem and the truth is that you can’t really do anything about the null anyway. Bummer.
- Well… sure, they tell you what they tell you. But what if you are measuring the wrong way? Doesn’t help you, does it? There are numerous tutorials on how to measure yet there’s still a lot of questions and potential for better ways to measure. Additionally, you may want to believe you fixed a problem because it’s visually not there, but what if you fixed the wrong thing? What if the bump at 1khz you knocked down was merely next to a null that can’t be fixed? So, you knocked down 1khz 9dB and you thought you fixed it only to sometime later realize you didn’t fix the real problem and the truth is that you can’t really do anything about the null anyway. Bummer.
- "Why can’t I trust my ear?"
- No one says you can’t. You should, however, question your brain.
- The problem with using your ear is simply that it’s easy to miss things or even to focus too much on something while altering what was good to begin with.
- For example, let’s say you hear a problem at 1khz; it’s pulling to the left. So, naturally, you start cutting the left side at 1khz and boost the right side at 1khz. Problem solved, right? Until you get in your car the next morning and it’s STILL there.
After some playing around you found that the problem really is due to a reflection from your right speaker. You wanted to believe you were fixing the problem and so you did… but you really didn’t. Another potential problem could be the issue at 1khz is due to a reflection; a harmonic of 500hz is causing the issue and if you wanted to fix the root of the problem, you needed to adjust 500hz. Not 1khz.
- No one says you can’t. You should, however, question your brain.
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