[TylersEclectic]

What are the thoughts on the GRAS RA0402 coupler in regards to the new 5128? I love that a new approach and standard has come about though, so cool! I'm a fan of more information is better than less lol... a great read, and I look forward to the next portions and future updates as you learn and share your experiences @jude

 

[noplsestar]

@jude please also share the new Focal Stellia measurement!!

 

[eldus]

AKG K240 test when? lol. Will there be a section for measurements on the site?

 

[castleofargh]

We all hear highs differently?

Hmmm....

All, maybe not. But you can expect some variations between people. Just your left and right ears being of slightly different shapes, probably cause significant high freq differences at the eardrums. As to why high freqs and not so much lower frequencies? Well that's because high frequencies have shorter wavelengths. It's just physics. Being shorter, they are impacted more by smaller variations in shapes, volumes, distances(reflections, resonances). But of course it's not strictly limited to high frequencies.

There is another possible cause of perceived variations, it's the fact that our subjective experience of sound is always that of some waves bouncing on our body and being altered by it before reaching the eardrum. That's our constant experience of real sound and we're so used to it that our brain actually uses those as cues to locate the sound source. With headphones and IEMs, the sound source bypasses some of those acoustic changes from our body(because the driver is so close to the ear). That could ironically lead to hearing a sound closer to what another listener will hear, yet feel more differences in our subjective impressions. Because our brain is still applying the usual mental and personal compensation(think EQ in this specific context of measuring FR with dummy heads) onto a signal that only needed part of it. So you and I might listen to the same headphone and feel more differences in our experience of the signature than when we're both listening to a guy playing the guitar while sitting close to each other.

And the third possible cause for change: placement. How we put on the headphone. How tight is the clamp because of the size of our skull and forcing the driver a little closer as a result. How far we insert the IEM. All that will have some impact on the sound reaching the eardrum.

 

[sidecross]

All, maybe not. But you can expect some variations between people. Just your left and right ears being of slightly different shapes, probably cause significant high freq differences at the eardrums. As to why high freqs and not so much lower frequencies? Well that's because high frequencies have shorter wavelengths. It's just physics. Being shorter, they are impacted more by smaller variations in shapes, volumes, distances(refl of ralityections, resonances). But of course it's not strictly limited to high frequencies.

There is another possible cause of perceived variations, it's the fact that our subjective experience of sound is always that of some waves bouncing on our body and being altered by it before reaching the eardrum. That's our constant experience of real sound and we're so used to it that our brain actually uses those as cues to locate the sound source. With headphones and IEMs, the sound source bypasses some of those acoustic changes from our body(because the driver is so close to the ear). That could ironically lead to hearing a sound closer to what another listener will hear, yet feel more differences in our subjective impressions. Because our brain is still applying the usual mental and personal compensation(think EQ in this specific context of measuring FR with dummy heads) onto a signal that only needed part of it. So you and I might listen to the same headphone and feel more differences in our experience of the signature than when we're both listening to a guy playing the guitar while sitting close to each other.

And the third possible cause for change: placement. How we put on the headphone. How tight is the clamp because of the size of our skull and forcing the driver a little closer as a result. How far we insert the IEM. All that will have some impact on the sound reaching the eardrum.

Add to what has been written above, our individual brain and consciousness is an interpretation of reality.

When it comes down to evaluation, hearing is an art and not subject to a true absolute, and is a reason music as art is a human characteristic.

 

[TYATYA]

Error of measurement makes me always to do sine sweep a headphone, earphone by my gear and judgement by my ears.
Shure kse looks bad graph of FR but to my ears, only narrow peak at 6300Hz existing, not at 9k and not so high sound pressure

 

[Evshrug]

We all hear highs differently?

Hmmm....

Yes, @castleofargh made a great intro post covering most of the info!

All, maybe not. But you can expect some variations between people. Just your left and right ears being of slightly different shapes, probably cause significant high freq differences at the eardrums. As to why high freqs and not so much lower frequencies? Well that's because high frequencies have shorter wavelengths. It's just physics. Being shorter, they are impacted more by smaller variations in shapes, volumes, distances(reflections, resonances). But of course it's not strictly limited to high frequencies.

There is another possible cause of perceived variations, it's the fact that our subjective experience of sound is always that of some waves bouncing on our body and being altered by it before reaching the eardrum. That's our constant experience of real sound and we're so used to it that our brain actually uses those as cues to locate the sound source. With headphones and IEMs, the sound source bypasses some of those acoustic changes from our body(because the driver is so close to the ear). That could ironically lead to hearing a sound closer to what another listener will hear, yet feel more differences in our subjective impressions. Because our brain is still applying the usual mental and personal compensation(think EQ in this specific context of measuring FR with dummy heads) onto a signal that only needed part of it. So you and I might listen to the same headphone and feel more differences in our experience of the signature than when we're both listening to a guy playing the guitar while sitting close to each other.

And the third possible cause for change: placement. How we put on the headphone. How tight is the clamp because of the size of our skull and forcing the driver a little closer as a result. How far we insert the IEM. All that will have some impact on the sound reaching the eardrum.

Yes! This is born out in testing.
Just to add one more thing to what is written above: you mention high frequencies have shorter wavelengths, and sound being altered before reaching the eardrum. Not too long ago I learned that our ears actually have a resonant frequency in the highs. All tubes have a resonant frequency where the wavelength is reinforced by the cylindrical structure... just like when you're humming in the shower, you might notice a pitch that suddenly is louder and the space seems to hum with you (If you haven't tried this yet... it's fun to find the right pitch, makes you feel powerful!). Now our ear canals are much narrower, thus the frequency is higher, and as evident by all our different IEM ear tip size needs, we have different resonant frequencies.

This is why I found Jude's "T-1000" gif so funny... and an apt consideration of the trickiness of ear simulators. Not only are our outer ears different to some degree, so is the diameter and bend of our inner ears. I would like to know more about the material used for ear simulation... is the silicone a close enough approximation of how reverberant and absorptive our skin is? And how much of an effect does the hairs on our skin affect the sound, especially as I notice some of my ear hair growing longer, haha!

Keep this in mind next time someone says the treble is too hot or too weak... it might not be their preferences, hearing damage, or psychoacoustics, it could just be their different physiology (at least partially).

 

[Piotr Michalak]

Headphone Measurements: The New Standard, Part 1

Wrote to these guys for a quote. Received no response. I understand that these hats are not cheap. But straight ignoring a potential prospect doesn't lead to sales either. Maybe these are reserved for established brands only? But then, why publish videos on youtube and head-fi and have a contact form, rather than just make selective sales and presentations? I wanna build a professional rig. However if almost no one publishes these new-standard measurements and almost no one has this thing, what's the value of this? We will only see a measurement from Jude once in a while maybe?

 

[halcyon]

Wrote to these guys for a quote. Received no response. I understand that these hats are not cheap. But straight ignoring a potential prospect doesn't lead to sales either. Maybe these are reserved for established brands only? But then, why publish videos on youtube and head-fi and have a contact form, rather than just make selective sales and presentations? I wanna build a professional rig. However if almost no one publishes these new-standard measurements and almost no one has this thing, what's the value of this? We will only see a measurement from Jude once in a while maybe?

Hey, it's a Danish company, what do you expect?

 

[Makiah S]

Yes, @castleofargh made a great intro post covering most of the info!


Yes! This is born out in testing.
Just to add one more thing to what is written above: you mention high frequencies have shorter wavelengths, and sound being altered before reaching the eardrum. Not too long ago I learned that our ears actually have a resonant frequency in the highs. All tubes have a resonant frequency where the wavelength is reinforced by the cylindrical structure... just like when you're humming in the shower, you might notice a pitch that suddenly is louder and the space seems to hum with you (If you haven't tried this yet... it's fun to find the right pitch, makes you feel powerful!). Now our ear canals are much narrower, thus the frequency is higher, and as evident by all our different IEM ear tip size needs, we have different resonant frequencies.

This is why I found Jude's "T-1000" gif so funny... and an apt consideration of the trickiness of ear simulators. Not only are our outer ears different to some degree, so is the diameter and bend of our inner ears. I would like to know more about the material used for ear simulation... is the silicone a close enough approximation of how reverberant and absorptive our skin is? And how much of an effect does the hairs on our skin affect the sound, especially as I notice some of my ear hair growing longer, haha!

Keep this in mind next time someone says the treble is too hot or too weak... it might not be their preferences, hearing damage, or psychoacoustics, it could just be their different physiology (at least partially).

This also applies to harmonics, not just the reinforcement of a fundamental tone

https://testhifi.com/2019/08/09/fla...rally-weighted-intermodulation-disconsonance/

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.497.2126&rep=rep1&type=pdf

So yea some of the difference in how we hear is partially due to physiology! An @jude it's awesome to see you guys are yet again pushing the standard for headphone measurements! It'll be great to see the new measurements off this system

 

[jude]

It's been busy at Head-Fi HQ, but I am still working on Part 2 of the article, and will post it as soon as I can, and it will of course include more measurements.

On the topic of doing headphone measurements: So that we could fit the Brüel & Kjær 5128 into the isolation enclosure with the 45CA, we reconfigured the 5128-C into a 5128-B for now (using the Brüel & Kjær UA-2180 support foot). On the full torso only one fixture or the other can fit on the pneumatic platform inside the enclosure -- but with the disembodied 5128, both fixtures fit on it.

​

Fig.1: Brüel & Kjær 5128-B (using UA-2180 support foot) with the GRAS 45CA​

Again, there will be more measurements in Part 2. And after it's posted we will thereafter be posting measurements regularly (we'll try posting them weekly to start). We have many 5128 measurements dating back to last December (though there weren't many performed during our lockdowns here in Michigan between March and June), and hundreds of measurements from the 45CA over the years.

Also related to doing headphone measurements: When we've done headphone measurements with visiting industry guests, they'll regularly comment about the measurement notes we log in our Audio Precision APx projects. One headphone engineer I recently screen-shared with in a video call suggested we post examples of these on the forums, thinking a few of you may find these interesting, too.

Here's an example of measurement notes for IEMs (Fig.2 below). Each line represents one sweep (from which many measurements can be derived). Each seating is noted, and we usually run at least two sweeps per seating. We record which fixture was used, whether the measurement was uncompensated or compensated, the voltage level, who did the seating, which ear tips were used, and any other noteworthy things.

​

Fig.2: Screen shot of some of the measurement notes for IEM measurements​

When we do AE/OE (around-ear/on-ear) measurements (Fig.3 below), we also note anything worthy of mention about position over the ears, headband size setting in clicks away from the smallest setting if the headband sizer has detents (or in estimated distance if it doesn't).

NOTE: I previously discussed how headband size settings can affect sensitivity, with measured examples: Measuring headphone sensitivity

​

Fig.3: Screen shot of some of the measurement notes for AE/OE (around-ear/on-ear) headphone measurements​

As you can imagine, these project notes definitely come in handy.

Again, I'll be posting Part 2 as soon as I can, and then regular measurements thereafter. Thanks for your patience, everyone.

 

[jwbrent]

It's been busy at Head-Fi HQ, but I am still working on Part 2 of the article, and will post it as soon as I can, and it will of course include more measurements.

On the topic of doing headphone measurements: So that we could fit the Brüel & Kjær 5128 into the isolation enclosure with the 45CA, we reconfigured the 5128-C into a 5128-B for now (using the Brüel & Kjær UA-2180 support foot). On the full torso only one fixture or the other can fit on the pneumatic platform inside the enclosure -- but with the disembodied 5128, both fixtures fit on it.

​

​

Fig.1: Brüel & Kjær 5128-B (using UA-2180 support foot) with the GRAS 45CA​

Again, there will be more measurements in Part 2. And after it's posted we will thereafter be posting measurements regularly (we'll try posting them weekly to start). We have many 5128 measurements dating back to last December (though there weren't many performed during our lockdowns here in Michigan between March and June), and hundreds of measurements from the 45CA over the years.

Also related to doing headphone measurements: When we've done headphone measurements with visiting industry guests, they'll regularly comment about the measurement notes we log in our Audio Precision APx projects. One headphone engineer I recently screen-shared with in a video call suggested we post examples of these on the forums, thinking a few of you may find these interesting, too.

Here's an example of measurement notes for IEMs (Fig.2 below). Each line represents one sweep (from which many measurements can be derived). Each seating is noted, and we usually run at least two sweeps per seating. We record which fixture was used, whether the measurement was uncompensated or compensated, the voltage level, who did the seating, which ear tips were used, and any other noteworthy things.

​

​

Fig.2: Screen shot of some of the measurement notes for IEM measurements​

When we do AE/OE (around-ear/on-ear) measurements (Fig.3 below), we also note anything worthy of mention about position over the ears, headband size setting in clicks away from the smallest setting if the headband sizer has detents (or in estimated distance if it doesn't).

NOTE: I previously discussed how headband size settings can affect sensitivity, with measured examples: Measuring headphone sensitivity

​

​

Fig.3: Screen shot of some of the measurement notes for AE/OE (around-ear/on-ear) headphone measurements​

As you can imagine, these project notes definitely come in handy.

Again, I'll be posting Part 2 as soon as I can, and then regular measurements thereafter. Thanks for your patience, everyone.

Having pre-ordered an EE Odin, I’m looking forward to seeing a graph with the new measurement method.

 

[John Buchanan]

Jude,
this is a very interesting development, leading to more consistent and accurate comparisons of target and recorded responses that could be very valuable in headphone production. It would be nice to see an Inner Fidelity type reference omnibus of headphone measurements with the new B and K Hats 5128. There often seems to be a lot of difference between what is measured and what you hear.

 

[rattlingblanketwoman]

Thanks for sharing! This is all very interesting but I was expecting something even more radical when I read the title such as the development of whole new set of figures-of-merit that would in some psycho-acoustically way combine the effects of frequency response, volume, timing, imaging, etc.

Anyway, was there any discussion about whether the sample size of 40 people was sufficient to derive the statistics for the new standard? I would think that human variability may be such that we cannot easily generalize these measurements to a presumably Gaussian distribution that applies to all races but I’m no expert in this field.

Straight off the bat 40 seemed like a very small sample size to me too.

 

[halcyon]

Straight off the bat 40 seemed like a very small sample size to me too.

That is woefully inadequate even by statistics standards, not to mention human perception variance.

However, much higher samples sizes are much more expensive to test, thus this is understandable.

I think this is a good start!