[b0dhi]

So if the resonance is at our ears, shouldn't we be EQing reality too? That resonance is just as present when you're listening to a live band or any other sound.

Remember that those measurements are what arrives at the ear, not what arrives at the mind. They don't account for processing the brain does.

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[PiccoloNamek]

No, we should not be EQing reality, nor does the resonance that I speak of occur when listening to live sound. The resonance occurs with headphones, earbuds, and in-ear monitors specifically due to the acoustic impedance mismatch phenomenon.

I just performed a very interesting test. I put my headphones down on my desk, and turned SineGen up to its loudest output. I ran through the entire frequency range, and as far as I can tell, my headphones have a nearly perfectly linear frequency response. It is only when I actually put them on, so that the transducers are closely coupled with my ear canal and eardrum, that the frequency response becomes uneven.

Quote:

Remember that those measurements are what arrives at the ear, not what arrives at the mind. They don't account for processing the brain does.

I don't know what this is supposed to be about. The experiments that we are using to find the resonance peaks are repeatable and verifiable, and confirm the data contained in the graphs I posted.

 

[iriverdude]

Shouldn't you EQ to correct for your own hearing range, taking into account any loss ie at higher frequencies if you've older or have mild hearing loss?

 

[PiccoloNamek]

If you're equalizing for both peaks and notches, that should take care of itself during the equalization process, as you attempt to achieve a uniform response to the sine wave and pink noise sample.

 

[b0dhi]

This is ISO 226:2003, which by the way is measured using speakers, not headphones:

The resonances of the outer ear as well as the inner ear are apparent.

What I'm saying is that if that's how sound is perceived in the real world (not flat), what would be the purpose of EQing flatness into our perceived audio resonse?

 

[PiccoloNamek]

Those are equal loudness curves, which describe the sound pressures needed to perceive a uniform response to sine waves at a particular loudness, with the very high and very low frequencies needing more and more boosting as the overall loudness level drops... and also have absolutely nothing to do with what I am talking about. Perhaps you should read this quote, carefully:

Quote:

Originally Posted by Linkwitz Labs The 7.5 kHz peak is due to the acoustic impedance mismatch between transducer, ear canal and ear drum causing a half wavelength resonance in the canal.

This is the problem I am talking about, and the problem I am trying to fix. It is an inevitable part of the headphone experience, and does not occur with speakers or in live situations, to my knowledge. The point of equalizing your headphones to flat is so that they give the purest possible reproduction of music. If you are equalizing properly, you will not have to worry about equal loudness curves, because that will take care of itself during the process. At any rate, the deeper problems of psychoacoustics are beyond the scope of this tutorial.

 

[oqvist]

Quote:

Originally Posted by oqvist /img/forum/go_quote.gif Interesting. However how can you get equalizers to work and still run bit perfect if you have an external DAC? I have an Elite PRO which have equalizers built in. Seems like you can´t use equalizers with foobar with asio for example. I guess getting an external EQ costs a lot or is there a good bang for the buck solution here

I quote myself... Learned that software eq is a bad thing and I noticed there is actually relatively cheap equalisers out there.. The ones I seen before has all been like 1000$ ones

 

[b0dhi]

Quote:

Originally Posted by PiccoloNamek /img/forum/go_quote.gif Those are equal loudness curves, which describe the sound pressures needed to perceive a uniform response to sine waves at a particular loudness, with the very high and very low frequencies needing more and more boosting as the overall loudness level drops... and also have absolutely nothing to do with what I am talking about. Perhaps you should read this quote, carefully: This is the problem I am talking about, and the problem I am trying to fix. It is an inevitable part of the headphone experience, and does not occur with speakers or in live situations, to my knowledge. The point of equalizing your headphones to flat is so that they give the purest possible reproduction of music. If you are equalizing properly, you will not have to worry about equal loudness curves, because that will take care of itself during the process. At any rate, the deeper problems of psychoacoustics are beyond the scope of this tutorial.

It's isn't just very low and very high frequencies, it's also frequencies between 1 and 10khz, which have lots of non-linearities. That much is obvious by just looking at the graph.

My question is how will someone know - just by listening, not measuring - what's caused by the headphone impedance mismatch and what's caused by the inherent resonances in the hearing system? There's a lot of non-linearity in the ISO speaker tests around 7khz already, without headphones (and related impedance mismatches) getting involved.

 

[zantetsuken]

thanks to the OP for the Electri-Q equalizer. good program =)

i still havent gone through what you hvae said in full detail but i will give it a bash. i dont know much about EQ just yet in intricate detail. i just clicked the "analyser" button and set it to output and then equalized based on the output graph it gave me.

 

[PiccoloNamek]

Quote:

My question is how will someone know - just by listening, not measuring - what's caused by the headphone impedance mismatch and what's caused by the inherent resonances in the hearing system?

I only just barely understand the concept of acoustic impedance as it is (too much math!), so I cannot provide a good technical reply to this. There are ways to test for this though. The best way I can think of would be to use a pair of studio monitors that you know to have a flat output, and a pair of headphones that you know to have a flat output (such as STAX, for example.)

Use the SineGen program with both the speakers and the headphones and note where the perceived amplitude of the sound increases. With the speakers, the sound will be more or less uniform, with an increase around 2.5-3kHz due to the pinna. If the speakers are truly flat, there will not be any sharp peaks in the upper mids or highs. With the headphones, however, the response will start to become increasingly jagged above 2kHz, with a sharp peak in the 5-8kHz range. You can verify the presence of the problem by taking the headphones off, placing them on the desk and turning the volume up to where you can hear a 1kHz tone clearly. If you run the frequency sweep again, it will suddenly appear to be much more uniform in amplitude. Put the headphones back on, and the problem comes back.

The human auditory system does not normally create such a large peak in that specific frequency range. It can only be due to the unnaturally close coupling of the headphones to the ear canal and eardrum. When I listen to music on my studio monitors, it does not have the exaggerated high frequency energy that it does when I listen with my headphones unequalized, even though my headphones have a technically flatter response.

Quote:

thanks to the OP for the Electri-Q equalizer. good program =) i still havent gone through what you hvae said in full detail but i will give it a bash. i dont know much about EQ just yet in intricate detail. i just clicked the "analyser" button and set it to output and then equalized based on the output graph it gave me.

Unfortunately, the analyzer does not know what you are hearing, so equalizing based on what it tells you does nothing. If you are interested, you should start with SineGen as soon as possible and see what you can find out.

 

[zantetsuken]

Quote:

Originally Posted by PiccoloNamek /img/forum/go_quote.gif I only just barely understand the concept of acoustic impedance as it is (too much math!), so I cannot provide a good technical reply to this. There are ways to test for this though. The best way I can think of would be to use a pair of studio monitors that you know to have a flat output, and a pair of headphones that you know to have a flat output (such as STAX, for example.) Use the SineGen program with both the speakers and the headphones and note where the perceived amplitude of the sound increases. With the speakers, the sound will be more or less uniform, with an increase around 2.5-3kHz due to the pinna. If the speakers are truly flat, there will not be any sharp peaks in the upper mids or highs. With the headphones, however, the response will start to become increasingly jagged above 2kHz, with a sharp peak in the 5-8kHz range. You can verify the presence of the problem by taking the headphones off, placing them on the desk and turning the volume up to where you can hear a 1kHz tone clearly. If you run the frequency sweep again, it will suddenly appear to be much more uniform in amplitude. Put the headphones back on, and the problem comes back. The human auditory system does not normally create such a large peak in that specific frequency range. It can only be due to the unnaturally close coupling of the headphones to the ear canal and eardrum. When I listen to music on my studio monitors, it does not have the exaggerated high frequency energy that it does when I listen with my headphones unequalized, even though my headphones have a technically flatter response. Unfortunately, the analyzer does not know what you are hearing, so equalizing based on what it tells you does nothing. If you are interested, you should start with SineGen as soon as possible and see what you can find out.

does this work with crappy headphones? im still waiting for my HD650s to come in so right now im just using a crap pair of TDK's. i tried to listen out for peaks how do i tell which is a peak? it all sounds normal to me. sorry if im asking silly questions here.

 

[leeperry]

ok I'm playing around w/ Ozone4 PMEQ in 32float(Ozone works internally in 64float) in ffdshow, it seems pretty good if I kill a small spike around 7K...need to run more tests.

basically what you wanna achieve is kill resonances if I got it right, the same type or resonance you would get on a resonating low pass filter used for electronic music?

I'm not sure how to find out whether there's more resonating freqs, but I'm still RTFM at this point.

I always thought of EQ as a calibration LUT file on a monitor, and this type of EQ tries to make the original stereo stream "match" our body natural freqs response it would appear

anyhow, the before/after is shattering

PS: the snare drum in "I wanna be your dog" is also resonating to death <click> <click> fixed

PS2 : there's some remaining resonances, easy to hear with the "don't let me be misunderstood" track on the KB1 sountrack.....need to find them and annihilate them

 

[leeperry]

alright, now we're talking business

the hiss at the beginning of "nancy sinatra - bang bang" on the KB1 soundtrack is perfect to hear resonances

Nancy's voice sounds even more natural that it ever did before

 

[geremy]

I was planning to use the burn-in wave generator which can generate white noise, pink noise, user defined frequency sweeps and single tone sine waves.

 

[PiccoloNamek]

Quote:

Originally Posted by leeperry /img/forum/go_quote.gif alright, now we're talking business the hiss at the beginning of "nancy sinatra - bang bang" on the KB1 soundtrack is perfect to hear resonances Nancy's voice sounds even more natural that it ever did before

Awesome! Now that's what I'm talking about. Looks awfully familiar too...

My response.

Linkwitz's response. Notice that the HD414's had some problems in the 2.5kHz range, too. But look at the response he discovered for the high frequencies. I'm beginning to see a pattern here.

Quote:

Originally Posted by geremy /img/forum/go_quote.gif I was planning to use the burn-in wave generator which can generate white noise, pink noise, user defined frequency sweeps and single tone sine waves.

The Burn in Wave generator does not allow for the sweeping of the sine wave by hand, though, which is important for determining where the peak is and how loud it is relative to other frequencies.

Quote:

does this work with crappy headphones? im still waiting for my HD650s to come in so right now im just using a crap pair of TDK's. i tried to listen out for peaks how do i tell which is a peak? it all sounds normal to me. sorry if im asking silly questions here.

It will work with any pair of headphones. I've even equalized cruddy pairs of grocery store headphones, just for kicks. To tell what is a peak and what isn't, just put the headphones on, load up the SineGen program (which I provided a link to), and press the "Power" button. Use the frequency slider to move the tone slowly up and down the frequency range. If there is a peak, you will perceive it as a sharp and sudden increase in volume on a particular group of frequencies.

You know, I think I will post some samples of music that I have heard that easily reveal the presence of the anomaly. They will be helpful demonstrating the problem to others.