DivineCurrent
500+ Head-Fier
I'm not sure where to post anything EQ related, as there are multiple EQ threads in many different places. Since what I am doing requires a computer and software, I thought I should post it here.
I want to share with everyone what I've been experimenting with, which is measuring headphones using in ear binaural microphones and correcting the frequency response with EQ. I am using these microphones from the Sound Professionals: https://www.amazon.com/gp/product/B00HAL0ZWU. They create very good binaural recordings, and work very well for other purposes just like what I am about to show you. I use these microphones with the Zoom H1 recorder.
Let me say first that this may be a very unorthodox way of measuring and adjusting headphone frequency response using EQ. However, I have found that this method makes my over ear headphones sound better. All measurements you see online use some sort of artificial dummy head device with ears that do not match exactly your own ear shape. As a result, the frequency response measurements you see everywhere do not match what your ears are hearing, sometimes the differences are very large, especially above 5 Khz. So far, I have tested this way of equalizing with the Sennheiser HD650, and the Beyerdynamic DT880. With this method, I have equalized the sound of these two headphones to sound extremely similar, following a typical speaker target curve within the Room EQ Wizard software. With it, the peaks of the DT880 are gone, and the treble performance of the HD650 is better, with the option of removing the mid-bass hump. I don't claim to know everything about audio science and frequency measurements as a whole, I just know this following method works very well for me, and I want to share this method so others can try it out.
Using Room EQ Wizard, I measure one earcup at a time, with a 10-20,000 Hz sine wave. The software automatically gives you a frequency chart after the measurement is complete.
Check levels before you measure. Levels around -15 dB work the best, and give room for peaks to be measured without clipping the microphone. I use my headphone amp to adjust the levels, but you can increase or decrease the mic sensitivity to get the required levels. Make sure you test the tone at comfortable normal listening levels, the same level you would listen to music. Make sure the binaural mics are not loose inside your ears, because their position can affect the frequency a lot.
Make sure under Preferences you have the left mic recording the left driver, and the right recording the right. Don't record both at the same time, or you will have one driver affecting the measurements of the other.
Here are the measurements of the left and right drivers of the Beyer DT880 respectively. That stuff at the bottom is phase response, which I have no knowledge about. Also, I set these graphs to have 1/24 octave smoothing, which you can adjust by clicking on the gear at the top right corner of the graph. No smoothing may be more accurate, but looks uglier.
Anyway, there is a peak around 5.5 Khz, and 8-10 Khz. There is a dip at 6.8 Khz, which may be the result of the shape of my ears, as it is also present with the HD650. For now, don't worry about the dips and focus on the peaks. These measurements confirm how well matched the drivers are. Due to pad wear and my irregular shaped head, my HD650s are not nearly as well matched in the mids. Anything above 10 Khz take with a grain of salt, because often the graphs do not represent what you hear in that area. I do not hear that large of a dip at 11-12 Khz, could be that the mics are placed right at the ear canal and not inside of the ear canal, where resonance can occur.
Once you have completed measuring both drivers, Click on the EQ button on the top right. On that page, you can customize the target curve to whatever you want. I find the default curve to work well for me tonally.
Under EQ filters, you want to try and match the frequency response to your desired curve. I had to use almost all 20 filters to get my desired response, but that shouldn't be a problem if you are using EqualizerAPO, which REW can output directly into. You can add as many filters as you want to EqualizerAPO, as far as I know.
There's a lot going on in this graph, but you can see the light blue shaded part is your EQ, the dark red line is the original response, and the light red line is your predicted response after EQ.
Keep in mind this is a graph for one driver, often the EQ you apply to one driver won't match the other one exactly enough. Luckily it didn't take much tweaking the right driver EQ for the left driver for the DT880, as they are already matched well.
Don't try to make it absolutely perfect, because it won't be. I brought down the response from 8-14 Khz a decibel from the target line because it sounded still too bright in that area for me, and also sounded bright with sine sweeps in that area. After applying EQ, you can take measurements again and see the actual result. Many times, it will not look like this predicted line.
EDIT: I forgot to mention, there is an option within the Filter Tasks tab that says "Match response to target". This automatically EQ's the original headphone's response to match the target curve for you. It tries to use the least amount of filters to achieve the target, so this may be the best way to correct the response. I set the flatness target to 1 dB.
Now, if you have EqualizerAPO installed, you can easily export a text file to the config folder to apply this EQ. If you want to measure both channels like what I am doing, just add a (Channel: L), and (Channel: 2) to your config file, with the corresponding filters underneath. It should look something like this:
I added a Preamp setting so that there will be no clipping.
That's pretty much it. I like to use SineGen to confirm that what I am hearing is close to flat, as I don't like to rely on just the graphs. You can get that program here: http://www.tucows.com/preview/502787
You can use any EQ program you want, but I just happened to have REW as an EQ and measurement program installed already. I found it's very easy to make headphone graphs with, and I couldn't find any other free programs online that make measurements. You could even make your EQ settings with REW and copy all the filter settings into your own EQ program.
Have fun experimenting, and if I didn't explain something correctly or missed some important detail just let me know.
I want to share with everyone what I've been experimenting with, which is measuring headphones using in ear binaural microphones and correcting the frequency response with EQ. I am using these microphones from the Sound Professionals: https://www.amazon.com/gp/product/B00HAL0ZWU. They create very good binaural recordings, and work very well for other purposes just like what I am about to show you. I use these microphones with the Zoom H1 recorder.
Let me say first that this may be a very unorthodox way of measuring and adjusting headphone frequency response using EQ. However, I have found that this method makes my over ear headphones sound better. All measurements you see online use some sort of artificial dummy head device with ears that do not match exactly your own ear shape. As a result, the frequency response measurements you see everywhere do not match what your ears are hearing, sometimes the differences are very large, especially above 5 Khz. So far, I have tested this way of equalizing with the Sennheiser HD650, and the Beyerdynamic DT880. With this method, I have equalized the sound of these two headphones to sound extremely similar, following a typical speaker target curve within the Room EQ Wizard software. With it, the peaks of the DT880 are gone, and the treble performance of the HD650 is better, with the option of removing the mid-bass hump. I don't claim to know everything about audio science and frequency measurements as a whole, I just know this following method works very well for me, and I want to share this method so others can try it out.
Using Room EQ Wizard, I measure one earcup at a time, with a 10-20,000 Hz sine wave. The software automatically gives you a frequency chart after the measurement is complete.
Check levels before you measure. Levels around -15 dB work the best, and give room for peaks to be measured without clipping the microphone. I use my headphone amp to adjust the levels, but you can increase or decrease the mic sensitivity to get the required levels. Make sure you test the tone at comfortable normal listening levels, the same level you would listen to music. Make sure the binaural mics are not loose inside your ears, because their position can affect the frequency a lot.
Make sure under Preferences you have the left mic recording the left driver, and the right recording the right. Don't record both at the same time, or you will have one driver affecting the measurements of the other.
Here are the measurements of the left and right drivers of the Beyer DT880 respectively. That stuff at the bottom is phase response, which I have no knowledge about. Also, I set these graphs to have 1/24 octave smoothing, which you can adjust by clicking on the gear at the top right corner of the graph. No smoothing may be more accurate, but looks uglier.
Anyway, there is a peak around 5.5 Khz, and 8-10 Khz. There is a dip at 6.8 Khz, which may be the result of the shape of my ears, as it is also present with the HD650. For now, don't worry about the dips and focus on the peaks. These measurements confirm how well matched the drivers are. Due to pad wear and my irregular shaped head, my HD650s are not nearly as well matched in the mids. Anything above 10 Khz take with a grain of salt, because often the graphs do not represent what you hear in that area. I do not hear that large of a dip at 11-12 Khz, could be that the mics are placed right at the ear canal and not inside of the ear canal, where resonance can occur.
Once you have completed measuring both drivers, Click on the EQ button on the top right. On that page, you can customize the target curve to whatever you want. I find the default curve to work well for me tonally.
Under EQ filters, you want to try and match the frequency response to your desired curve. I had to use almost all 20 filters to get my desired response, but that shouldn't be a problem if you are using EqualizerAPO, which REW can output directly into. You can add as many filters as you want to EqualizerAPO, as far as I know.
There's a lot going on in this graph, but you can see the light blue shaded part is your EQ, the dark red line is the original response, and the light red line is your predicted response after EQ.
Keep in mind this is a graph for one driver, often the EQ you apply to one driver won't match the other one exactly enough. Luckily it didn't take much tweaking the right driver EQ for the left driver for the DT880, as they are already matched well.
Don't try to make it absolutely perfect, because it won't be. I brought down the response from 8-14 Khz a decibel from the target line because it sounded still too bright in that area for me, and also sounded bright with sine sweeps in that area. After applying EQ, you can take measurements again and see the actual result. Many times, it will not look like this predicted line.
EDIT: I forgot to mention, there is an option within the Filter Tasks tab that says "Match response to target". This automatically EQ's the original headphone's response to match the target curve for you. It tries to use the least amount of filters to achieve the target, so this may be the best way to correct the response. I set the flatness target to 1 dB.
Now, if you have EqualizerAPO installed, you can easily export a text file to the config folder to apply this EQ. If you want to measure both channels like what I am doing, just add a (Channel: L), and (Channel: 2) to your config file, with the corresponding filters underneath. It should look something like this:
I added a Preamp setting so that there will be no clipping.
That's pretty much it. I like to use SineGen to confirm that what I am hearing is close to flat, as I don't like to rely on just the graphs. You can get that program here: http://www.tucows.com/preview/502787
You can use any EQ program you want, but I just happened to have REW as an EQ and measurement program installed already. I found it's very easy to make headphone graphs with, and I couldn't find any other free programs online that make measurements. You could even make your EQ settings with REW and copy all the filter settings into your own EQ program.
Have fun experimenting, and if I didn't explain something correctly or missed some important detail just let me know.
