[cupofwrathcom]

This video explains how to use the program called "Equalizer APO" to improve the sound of speakers and headphones. I'm a believer in this, but part of the difficulty is using the software itself which can be confusing.



The idea is to flatten the peaks and raise the dips to hammer the response flat.

Of course some people want no filters and 100% natural analog sound. I see both sides, but I believe a n huge improvement in sound quality is possible with software like Equalizer APO. It works well on full range drivers, which most headphones are.
Of course it all comes down to the measurements.

 

[msing539]

The idea is to flatten the peaks and raise the dips to hammer the response flat.

Yeah but not flat.

 

[cupofwrathcom]

Yeah but not flat.

It's like trying to flatten a dent, it will never be perfect.

 

[msing539]

It's like trying to flatten a dent, it will never be perfect.

Lol no what I meant is we don't try to EQ a totally flat FR.

 

[cupofwrathcom]

Lol no what I meant is we don't try to EQ a totally flat FR.

Trying to make the FR totally flat is a fool's errand. Most headphones are small full range cones that go into break up and so the peaks can be notched and dips can be raised a little. At least you don't have to deal with the room like with speakers.

 

[catscratch]

As far as EQing to flat goes...

We hear resonances and time domain issues as peaks, and if you try to EQ to a completely flat FR, what you end up with is dips in the FR where the resonances are which will affect the tembre.

The flip side of this is, resonances will ALSO affect the tembre, so trying to leave them alone isn't really the right thing either. You basically need a subtle touch - you reduce the peaks, flatten out the midrange, bring the bass to a level that you want, and use both sine sweeps / test tone generators as well as pink noise to hear where the overt colorations are. You should get the FR close to flat, but you don't need to obsess over a ruler-flat FR at least in the highs.

Also, APO is not a very good equalizer, and it has limitations. Putting in high-q filters, generally above Q3 or so, will introduce artifacts into the sound. To get the FR ruler flat in the highs you usually have to stack multiple high-q filters together, and that will always sound terrible and overprocessed.

However even APO is a powerful tool that can transform many headphones into something much better, and it's free. It's well worth learning how to use it.

The TL;FR is, do the minimum amount of EQ you can get away with and use a smooth a curve as you can.

The best way to do this is to start with headphones that don't need much EQ in the first place. But that, uh... sort of limits your options lol. Most headphones absolutely suck as far as FR accuracy goes.

 

[cupofwrathcom]

As far as EQing to flat goes...

We hear resonances and time domain issues as peaks, and if you try to EQ to a completely flat FR, what you end up with is dips in the FR where the resonances are which will affect the tembre.

The flip side of this is, resonances will ALSO affect the tembre, so trying to leave them alone isn't really the right thing either. You basically need a subtle touch - you reduce the peaks, flatten out the midrange, bring the bass to a level that you want, and use both sine sweeps / test tone generators as well as pink noise to hear where the overt colorations are. You should get the FR close to flat, but you don't need to obsess over a ruler-flat FR at least in the highs.

Also, APO is not a very good equalizer, and it has limitations. Putting in high-q filters, generally above Q3 or so, will introduce artifacts into the sound. To get the FR ruler flat in the highs you usually have to stack multiple high-q filters together, and that will always sound terrible and overprocessed.

However even APO is a powerful tool that can transform many headphones into something much better, and it's free. It's well worth learning how to use it.

The TL;FR is, do the minimum amount of EQ you can get away with and use a smooth a curve as you can.

The best way to do this is to start with headphones that don't need much EQ in the first place. But that, uh... sort of limits your options lol. Most headphones absolutely suck as far as FR accuracy goes.

There are some good thoughts in this post. A couple things to consider is that Equalizer APO contains many different filters. There are high shelf and low shelf and notch filters etc. It also has equalizers. My experience has been Its better to adjust the sound with simpler filters because this prevents things like artifacts. Just like having a too complex crossover can be detrimental so can too much digital processing.

Its a powerful tool but it comes to down to proper use and measurements. it also can't adjust the dispersion of sound from a speaker so it has its limits. Headphones remove the room and dispersion/phase issues which is nice. Equalizer APO is also great for something like a full range on an open baffle that's hard to design a crossover for.

 

[cupofwrathcom]

double post,

 

[Dixter]

so here is a question for ya.... lets say we take a nice headphone and a EQ/DSP box and a set of in ear microphones.... with the microphones in the ears and the headphones being worn over the mics we let the box perform a frequency sweep of say 20 to 20K and the box now has a recording of how the headphones frequency response is and how the headphones interact with the outer ears of the person wearing the headphones.. so now we tell the box to create a EQ where the Frequency Response of the headphones gets adjusted to perfectly flat... now lets take the mics out of the ears to expose the inner ear to the headphones that are now perfectly EQ flat... and now we get to listen to the different frequencies and fine tune the Flat EQ... maybe your left ear has an issue with high freq and you get to adjust both the inner left ear and right ear... so now we have a perfectly flat frequency response of those headphones all the way to the inner ear.... so lets just call that Reference EQ..... now lets go to a super fancy audio store and the owner lets you bring your box into one of his sound demo rooms.... the room is perfectly tuned and he has the room filled with speakers and amps costing say $250K... so you set up the box so it will play the frequency sweeps thru those speakers/amp and you are sitting in the room with those in ear mics again... but now the box is recording each of the speakers in the room and its position in relation to where your head is pointed.... so now you have a recording of each speaker how it sounds from your left ear and your right ear... now with the box, you apply the sound demo room over the top of the reference EQ... now you have a set of headphones that sound exactly like that audio store demo listening room... you might have paid $1500 for those headphones... but now your sitting at home in your listening chair and you are listening to a $250K demo room... with your favorite songs or movie.... sounds cool doesn't it... and if you like the demo sound room better because you can " feel " the speakers while playing then all you have to do is hook up a sub woofer to the box.... now it sounds cool and you get the tactical also...

 

[Dixter]

double post,

what kind of setup do you use... headphone and amp ??

 

[cupofwrathcom]

so here is a question for ya.... lets say we take a nice headphone and a EQ/DSP box and a set of in ear microphones.... with the microphones in the ears and the headphones being worn over the mics we let the box perform a frequency sweep of say 20 to 20K and the box now has a recording of how the headphones frequency response is and how the headphones interact with the outer ears of the person wearing the headphones.. so now we tell the box to create a EQ where the Frequency Response of the headphones gets adjusted to perfectly flat... now lets take the mics out of the ears to expose the inner ear to the headphones that are now perfectly EQ flat... and now we get to listen to the different frequencies and fine tune the Flat EQ... maybe your left ear has an issue with high freq and you get to adjust both the inner left ear and right ear... so now we have a perfectly flat frequency response of those headphones all the way to the inner ear.... so lets just call that Reference EQ..... now lets go to a super fancy audio store and the owner lets you bring your box into one of his sound demo rooms.... the room is perfectly tuned and he has the room filled with speakers and amps costing say $250K... so you set up the box so it will play the frequency sweeps thru those speakers/amp and you are sitting in the room with those in ear mics again... but now the box is recording each of the speakers in the room and its position in relation to where your head is pointed.... so now you have a recording of each speaker how it sounds from your left ear and your right ear... now with the box, you apply the sound demo room over the top of the reference EQ... now you have a set of headphones that sound exactly like that audio store demo listening room... you might have paid $1500 for those headphones... but now your sitting at home in your listening chair and you are listening to a $250K demo room... with your favorite songs or movie.... sounds cool doesn't it... and if you like the demo sound room better because you can " feel " the speakers while playing then all you have to do is hook up a sub woofer to the box.... now it sounds cool and you get the tactical also...

Listening of a recording of music played through expensive speakers. Isn't what you want. Its like recording a movie at the theaters through your iphone. Every time something is played and rerecorded it gets changed by the room. Sometimes it can pick up a live music sound.

With speakers the room is very important and the sound is bouncing all over the place so its very complex. Headphones are much simpler but I wouldn't say equalizer apo is bad for speakers, just trickier. Say you have a ribbon and want to adjust the response it would work well. You could also do an entire crossover with dsp which some people do.

 

[Dixter]

Listening of a recording of music played through expensive speakers. Isn't what you want. Its like recording a movie at the theaters through your iphone. Every time something is played and rerecorded it gets changed by the room. Sometimes it can pick up a live music sound.

With speakers the room is very important and the sound is bouncing all over the place so its very complex. Headphones are much simpler but I wouldn't say equalizer apo is bad for speakers, just trickier. Say you have a ribbon and want to adjust the response it would work well. You could also do an entire crossover with dsp which some people do.

I don't think you understood my post... I'm not recording the music... the box sends out frequency sweeps to determine the frequency response of each speaker in the room... that recording gets turned into an EQ file and that EQ gets loaded on top of the flat EQ from the headphones to your ears.... recording studios use this method to create records and movies.... it will allow the recording studio to handle 24 channels of music over a set of headphones... you can't tell the difference between you sitting in that audio demo room or if you are sitting in your living room...

 

[cupofwrathcom]

what kind of setup do you use... headphone and amp ??

I have speakers that I designed with a full range and woofer. I prefer soft cones, domes, small full rangers. There character of a driver can't be changed digitally. Paper will always have a certain sound vs metal. Some disagreement with this.

 

[cupofwrathcom]

The equalization is supposed to make the room flat. So if you use that profile in a headphone you've made it less flat. Maybe you'd get lucky and like the sound.

 

[Dixter]

I have speakers that I designed with a full range and woofer. I prefer soft cones, domes, small full rangers. There character of a driver can't be changed digitally. Paper will always have a certain sound vs metal. Some disagreement with this.

and the sound signature of you custom speakers can be emulated 100% and applied to your headphones... you can't tell the difference in the sound signature .... Audeze has a software plug in called Audeze Reveal+ plugin ... they implemented the tech I wrote about and that plug in has a couple of recording studios they have EQ setup for the particular speakers used in those recording studios but you get to chose what headphone model you are wearing for the emulations...