AKG K245 Review

[isostasy]

I found a cheap listing for these as parts/not working so bought them as a base for installing Peerless 50mm drivers. But to my surprise (pleasant or disappointed, depending on your viewpoint), they work perfectly! What could I do but give them a listen and take some measurements?

AKG says 'The new K245 represents the culmination of decades of refinement—from the transducers, to the porting, to the fit and finish', that they 'offer the best-in-class frequency response', and that the 50mm drivers offer 'greater low-frequency extension and detailed bass reproduction'. This sounds like a good amount of effort going into either R&D or copywriting. RRP is $89 USD but they are on sale for less than that most places I looked.

(from headphonecheck)

I quite like the design, it's reminiscent of a few different AKG models put together. There is a folding mechanism which is unique in combination with the suspension strap.

Unfortunately this does not fit small heads like mine very well, though I have found this to be the case with other suspension strap designs. I put some foam under the strap and held it in place with one of those wool headband wraps and this solved the problem. Sticking a HD650 foam pad on with double sided tape would probably work well too.

The pads, conversely, do not feel very roomy. They're 53mm inside which is plenty front-to-back but I have to give them a wiggle each time I put them on to ensure the tops and bottoms of my ear are tucked in rather than pressed against my head by the pad. Even then my lobes feel a bit squished against the inside of the pad.


Measurements

My new approach to measurements is to take both in-ear and flat-plate coupler measurements. This is to avoid being mislead by some deficiencies of the FPC, and it also provides confidence when I can see agreement between each system. I make new reference measurements with my HD6XX every time I do in-ear measurements because it is almost impossible to place the mic in the same position each time.

Channel matching was excellent so following measurements just use R for easy readability.

This looks pretty good. Bass response is great! Now to check with an in-ear measurement:

This is promising as features seem broadly consistent across both measurement systems. The deep 8kHz dip on the HD6XX and tall ~8.5kHz peak on the K245 both correspond to a phase shift so I'm not sure about EQing that. The FPC showed the K245 was elevated in the whole region 6-11kHz above the HD6XX however, so will need listening to see if there are any problems here.


Listening

These are not bad at all. The 1-2kHz dip, combined with the already warm tilt, makes it sound a bit closed in and lacking clarity in the mids. This makes some songs a bit artificial sounding.

With the following EQ I think it sounds really good and fixes those issues completely:

PK Fc 1350 Hz Gain 3.70 dB Q 2.200
PK Fc 200.0 Hz Gain -2.00 dB Q 1.200

Just the first 1350Hz filter makes a big improvement, and the second is if you want to reduce the apparent warmth a bit more (this is the same filter I use for my HD6XX).

I tried multiple ways to see if I could bring up 3-5kHz but it always sounded worse.

I had a go at reducing the broad treble elevation as well but I don't think it's bothersome enough to require any EQ. I think a proper GRAS measurement would be the only way to confirm if it's 'real' or not anyway. Without EQ some cymbals appear slightly pronounced which is nice. With EQ a sort of shimmer is removed from some songs which may appear like some coloration is being removed. It's a wash really.

This is a starting point if you are bothered:

PK Fc 7400 Hz Gain -4.50 dB Q 5.000
PK Fc 8680 Hz Gain -2.00 dB Q 5.000


Conclusion

I really like these! They need at least the 1350Hz filter to sound their best, then it's just a matter of adjusting bass and treble to taste. I can't think what would be better for the price. I would really like to see someone with an industry standard rig measure them still.

My main reservation is availability of pads. AKG don't appear to offer replacements at all which is disappointing. There are options from Geekria in pleather and velour but I'm wary of the changes to FR these might bring.

Thanks

 

[IAtaman]

Thank you for the write-up, it was a nice read.

Bass response looks really good for what is advertised as an open back.

In some regions FR seems to be quite close to that of HD6XX with FPC but quite different with in-ear mics. Why is that, different acoustic impedance? Which one is more reliable based on your listening tests?

It was super cheap on amazon.co.uk with free international delivery so ordered one. Should arrive in a week or so - looking forward to testing it.

 

[isostasy]

@IAtaman thanks yes the bass is one of the best features! Definitely doesn't require any boost, though it does handle a low shelf if you want to shake your brain.

r.e. the differences between the FPC and in-ear, I just found out a way to compensate using the calibration feature in REW:

So agreement is pretty much perfect until 2kHz then some small differences until 5kHz then massive differences.

I'm fairly certain 2-4khz difference is due to distance from the microphone on the FPC. The only headphones I have found to measure 'true' here in the sense that they match in-ear measurements are on-ear headphones or those which couple tightly to the ear such as Sennheiser HD6xx series. As soon as you you put on a headphone with angled drivers or thicker pads you see a dip here which isn't 'real'. This becomes apparent when you try to EQ it and up and it sounds bad. @solderdude has spoken about this before and sometimes draws a line on his measurements to show 'perceived' response because of this (see his HD560S review).

People have called this out in the past, with arguments such as "it's on a flat plate, this represents FR before the ear, therefore all headphones should be treated equally, there is no 'perceived' response" but from my experience this is not the case and solderdude is correct. I measured a pair of Hifiman HE400SE the same way and you can see exactly the same phenomenon, though even more extreme (~5dB shortfall at 3kHz on FPC) because the Hifiman has thick and angled pads.

The dip around 4.6kHz agrees on both though this is a red herring because in reality it shifts slightly depending on how you put the headphones on. i.e. there is a dip around there but it appears to be a phase shift, maybe from some interaction with the ear, so differs with placement. This might be something to do with why amir says not to EQ areas with phase shifts. I tried adding EQ filters here but it always sounded bad, probably because it is so deep and narrow that if the headphones are in slightly the wrong place it doesn't match up and you just give yourself a massive peak. The fact it's narrow is a blessing too however as it means it is not noticeable listening to music.

And then above 6kHz, I'm guessing the main part you're talking about, is a bit of a crap-shoot and it depends what you mean by 'reliable'. The massive 8kHz peak on the in-ear K245 measurement is definitely not real and depending on the mic placement measurements can be all over the place, which I would say means they are therefore not 'reliable'. At this point I think you're seeing more about the ear itself than the particular headphone being measured.

At gun-point I'd say the FPC is more 'reliable' here because it suggests there is some elevation above the HD6XX, and this is audible in that it brings some sounds such as cymbals louder in the mix if you listen out for it. This is with the caveat that it almost certainly doesn't differ from the HD6XX precisely the same way as it measures. A FPC is so physically different to an actual ear that trying to draw solid conclusions about the treble response is a fool's errand. This kind of comes back to what amir always says even about his GRAS system I think.

Above about 15kHz ignore it completely, I'm using cheap uncalibrated electret mics so there's just no meaningful info there.

As for why there are such big differences, I don't know enough to say I got lost a long time ago in the 5128 thread when they were talking about impedance.

Let me know your thoughts when it arrives!

 

[IAtaman]

Thanks to unsustainable wonders of international shipping, just received it in less than a week.

First impressions:

• Bass is amazing! Like, LCD-X level amazing. Without any boost. Holy moly, what black magic is this - are these really open back?
• It was sounding a bit nasal, even with that -2db at 200Hz to me. I moved it down a bit to 150hz and increased it to -2.5db which made it better. I am one of those people who like the tuck of Harman target at around 200hz.
• I combined the two sharp filters at 7400 and 8660 to one Q=3 one at 8000 and I think I am happy with it.
• Something is a bit off tonality wise still but I can not put my finger on it. I am gonna listen to this a bit more later with more focus when I got the time.
• Hot take : K245 > K371

Cans are a bit small but still covers my ears rather than sitting on top of them. They are light, comfortable. They fold nicely. At first impression, they have good detail and spatial qualities as well. They don't require a 500mW amp to drive. I think they have the potential to be an amazing headphone. Thank you for the inspiration to buy these, could not be happier.

Looking forward to spending more time with them.

 

[an5783]

Great to see more love for these headphones. I've had them for a year or so and love them. They get way more use than my K712s, although the K245s can't compete on soundstage. Thanks both for sharing your thoughts on PEQ.

There's an extensive thread discussing these cans (as well as the K175 and K275) and some mods over on head-fi, if you want more details on other people's thoughts on tonality and replacement pads (which still remains inconclusive...). The latter pages refer almost exclusively to the K245. I joined ASR just now to point you there as I figured you'd both find it interesting. Not sure if posting URLs is permitted here, will see if the mods allow it.

New AKG headphones K175, K245, K275

Looks interesting, although I don't understand why that headphone design and foldable....

www.head-fi.org

 

[IAtaman]

@isostasy do you have the setup to measure distortion by any chance?

 

[isostasy]

@isostasy do you have the setup to measure distortion by any chance?

I do have distortion measurements from REW but I don't know if they're accurate. I don't know the correct process for producing reliable distortion measurements at all to be honest... I always thought you need to do some calibration with the soundcard and mic to begin with but I might be wrong?

n.b. I have replies to the above posts but will come later when I have time.

 

[isostasy]

Thanks to unsustainable wonders of international shipping, just received it in less than a week.

First impressions:

• Bass is amazing! Like, LCD-X level amazing. Without any boost. Holy moly, what black magic is this - are these really open back?
• It was sounding a bit nasal, even with that -2db at 200Hz to me. I moved it down a bit to 150hz and increased it to -2.5db which made it better. I am one of those people who like the tuck of Harman target at around 200hz.
• I combined the two sharp filters at 7400 and 8660 to one Q=3 one at 8000 and I think I am happy with it.
• Something is a bit off tonality wise still but I can not put my finger on it. I am gonna listen to this a bit more later with more focus when I got the time.
• Hot take : K245 > K371

Cans are a bit small but still covers my ears rather than sitting on top of them. They are light, comfortable. They fold nicely. At first impression, they have good detail and spatial qualities as well. They don't require a 500mW amp to drive. I think they have the potential to be an amazing headphone. Thank you for the inspiration to buy these, could not be happier.

Looking forward to spending more time with them.

Good to hear you like it! It's definitely open back, though I think the front volume is completely sealed so it would meet the definition of semi-open. There is porous black paper under the grille so you can't see straight through like you might expect.

Did you use the filter to fill in the 1.5khz dip and still find it nasally? I may try a broader filter at 8kHz as you have done because, after more listening, I am starting to think there is too much treble. Maybe this is contributing to your sense something is off in the tonality.

Great to see more love for these headphones. I've had them for a year or so and love them. They get way more use than my K712s, although the K245s can't compete on soundstage. Thanks both for sharing your thoughts on PEQ.

There's an extensive thread discussing these cans (as well as the K175 and K275) and some mods over on head-fi, if you want more details on other people's thoughts on tonality and replacement pads (which still remains inconclusive...). The latter pages refer almost exclusively to the K245. I joined ASR just now to point you there as I figured you'd both find it interesting. Not sure if posting URLs is permitted here, will see if the mods allow it.

New AKG headphones K175, K245, K275

Looks interesting, although I don't understand why that headphone design and foldable....

www.head-fi.org

Thank you, I had looked through but don't have an account over there.

I was going to write some long responses to some of the opinions expressed there but instead will just advise to take the discussions around pads and mods with a large handful of salt. People can write all sorts of clever sounding stuff about impedance and damping and and resonance and nonlinearities but if there is no evidence of what they talk about in frequency response measurements then it is of limited value.


Do you have any idea what measuring equipment is being used here?

 

[IAtaman]

Let me preface all below with the fact that I am not a trained listener, nor I think I have any special skill or ability when it comes to hearing, and that I do not know anything about acoustics. All this is just playful experimentation for me.

Good to hear you like it! It's definitely open back, though I think the front volume is completely sealed so it would meet the definition of semi-open. There is porous black paper under the grille so you can't see straight through like you might expect.

Is it definitely open back? When I cup my hands on the earcups, sound changes a bit but not by a much, as opposed other open backs I have with which tonality starts to change when my hands come close to the earcups. I read the thread @an5783 shared (thanks for that by the way) and I understand there are gaps at the back, but I am no sure why closing the earcups makes so little difference to the sound.

Did you use the filter to fill in the 1.5khz dip and still find it nasally? I may try a broader filter at 8kHz as you have done because, after more listening, I am starting to think there is too much treble. Maybe this is contributing to your sense something is off in the tonality.

I did. It did not fix the tuning issue for me.

I was playing with the EQ, trying to AB it with other headphones ( I think I am going to add AB functionality to camillaNode as it is a pain in the back to level match and AB) and I have landed on 2 LS filters for the bass.

Filter 1: ON LSC Fc 60 Hz Gain 3 dB Q 0.7
Filter 2: ON LSC Fc 300 Hz Gain -1.8 dB Q 0.7

For 1K-2K region, I thought the hole was not unlike that of some Hifiman headphones so I "stole" the filters from Oratory's Hifiman XS EQ for the same range, and I have to say, they sound a lot better to me now and that nasal quality is all but disappeared. Something still sounds a bit off, a bit "resonant" if that makes sense, but I am quite happy with this for now.

For the 5-8K region, I played with that area as well, and landed on a double filter like yours. Here is what I use at the moment. Give it a try if you can please and let me know what you think.

Preamp: -9dB dB
Filter 1: ON LSC Fc 60 Hz Gain 3 dB Q 0.7
Filter 2: ON LSC Fc 300 Hz Gain -1.8 dB Q 0.7
Filter 3: ON PK Fc 1450 Hz Gain 1.7 dB Q 4
Filter 4: ON PK Fc 1950 Hz Gain 4.3 dB Q 1.78
Filter 5: ON PK Fc 5000 Hz Gain -3.1 dB Q 3
Filter 6: ON PK Fc 7600 Hz Gain -3.5 dB Q 2

 

[isostasy]

Let me preface all below with the fact that I am not a trained listener, nor I think I have any special skill or ability when it comes to hearing, and that I do not know anything about acoustics. All this is just playful experimentation for me.


Is it definitely open back? When I cup my hands on the earcups, sound changes a bit but not by a much, as opposed other open backs I have with which tonality starts to change when my hands come close to the earcups. I read the thread @an5783 shared (thanks for that by the way) and I understand there are gaps at the back, but I am no sure why closing the earcups makes so little difference to the sound.


I did. It did not fix the tuning issue for me.

I was playing with the EQ, trying to AB it with other headphones ( I think I am going to add AB functionality to camillaNode as it is a pain in the back to level match and AB) and I have landed on 2 LS filters for the bass.


For 1K-2K region, I thought the hole was not unlike that of some Hifiman headphones so I "stole" the filters from Oratory's Hifiman XS EQ for the same range, and I have to say, they sound a lot better to me now and that nasal quality is all but disappeared. Something still sounds a bit off, a bit "resonant" if that makes sense, but I am quite happy with this for now.

For the 5-8K region, I played with that area as well, and landed on a double filter like yours. Here is what I use at the moment. Give it a try if you can please and let me know what you think.

It is open, see image here from above head-fi thread: there's permeable black paper over all those holes in the housing which means it looks closed. I admit there's loads of junk in the the middle of the cup but this is the case with AKG models like the K702 also. The driver itself is uncovered too.

Contrast this with the closed K275 which has no holes in the cup and the driver has a plastic cover.

I can make a measurement with the cup covered if you like?

I gave your EQ a go, I find the 1950Hz adds too much. Here's what it looks like:

Otherwise it's quite similar, I wonder if the reduction at 7.6kHz is the main thing contributing to your preference. I'm not sure about the reduction at 5kHz: the measurements suggest this is already in deficit but then it does sound like something is going on in the area you EQed.

 

[IAtaman]

It is open, see image here from above head-fi thread: there's permeable black paper over all those holes in the housing which means it looks closed. I admit there's loads of junk in the the middle of the cup but this is the case with AKG models like the K702 also. The driver itself is uncovered too.

Contrast this with the closed K275 which has no holes in the cup and the driver has a plastic cover.

I can make a measurement with the cup covered if you like?

Yes, that is the exact post I was referring to when I said I read the thread an5783 shared and I understand there are gaps at the back.

Thank you for the offer. I do not want to create too much bother for you, but if this is also interesting to you and if you don't mind measuring how covering the cup changes the FR with K245 and HD6xx I would be interested to see that.

I gave your EQ a go, I find the 1950Hz adds too much. Here's what it looks like:

View attachment 300028

Otherwise it's quite similar, I wonder if the reduction at 7.6kHz is the main thing contributing to your preference. I'm not sure about the reduction at 5kHz: the measurements suggest this is already in deficit but then it does sound like something is going on in the area you EQed.

Thank you very much for this. I take it blue line is my made up EQ from the hump at around 2K. That looks like to much indeed. I will dial it down 2db and see how that works.

For 7.6K area - I am not sure but I don't think so. Without that is sounds a tad bit shrill but not nasal.

 

[IAtaman]

I find myself using these cans almost exclusively the last couple of days and I have been really enjoying them. I think these will be my headphones of choice to take with me on vacation. My only complaint is the size of the pads - they are a bit too small for me. I am tempted to order a pair of Brainwavz 100mm round, perforated earpads in the hopes that they are gonna fit my ears better. I am a tiny bit worried that I am gonna lose any track of the tuning and will not have any measurements to refer to with those pads but I can live with that for a while. Maybe I will get some in-ear mics and measure them on my head and see how that goes after holidays.

 

[isostasy]

I find myself using these cans almost exclusively the last couple of days and I have been really enjoying them. I think these will be my headphones of choice to take with me on vacation. My only complaint is the size of the pads - they are a bit too small for me. I am tempted to order a pair of Brainwavz 100mm round, perforated earpads in the hopes that they are gonna fit my ears better. I am a tiny bit worried that I am gonna lose any track of the tuning and will not have any measurements to refer to with those pads but I can live with that for a while. Maybe I will get some in-ear mics and measure them on my head and see how that goes after holidays.

I haven't been using them much but took them out for some measurements which has thrown up some interesting things:

When I measure headphones with leather pads I place a layer of foam on the flat plate, otherwise the seal is 'too good' and becomes unrepresentative of the true response. This is supported by my in-ear measurements which show that the perfect seal on the flat plate does not match the lower end response on my actual head.

However in the case of the K245 you can see that rather than just affecting just the bass, e.g. by causing roll-off when seal is breached as is typical, varying the seal tilts the entire response to about 6kHz.

With a perfect seal, which is impossible on your head (unless you're bald maybe?), you get a hefty bass boost and a big dip in the midrange. If you completely breach the seal it tilts all the way up and the response just becomes flat throughout this region. The orange trace is what I started with, and which happened to match my in-ear measurement in bass response and that 1.5kHz dip as well.

The issue clearly is that with such a seal-dependent response, judging preference and designing EQ becomes very difficult. This is what I'm trying currently:

PK Fc 1350 Hz Gain 3.70 dB Q 2.200
PK Fc 200.0 Hz Gain -2.00 dB Q 1.200
PK Fc 7400 Hz Gain -6.00 dB Q 5.000
PK Fc 8680 Hz Gain -4.00 dB Q 5.000
PK Fc 4230 Hz Gain 3.00 dB Q 2.000

First two are the same, the I took a couple more dB off the 7400Hz and 8680Hz filters from before, then I added the 4230Hz to address the measured dip there.

I think it's getting there but, at 6 filters, it's undermining the premise of a neutral open back with enough bass to minimise the need for EQ.

I don't know what the answer is to this unfortunately. An industry standard measurement might help but if the seal variations on the FPC translate to real life usage, it's difficult make a definite judgment of sound quality and EQ recommendations.

n.b. hand covering back cup for your interest:

It is certainly a small difference though I imagine completely sealing off the cup would be more significant.

 

[IAtaman]

n.b. hand covering back cup for your interest:
It is certainly a small difference though I imagine completely sealing off the cup would be more significant.

Thank you very much for that. Seems like barely any change in bass and lower mids which aligns with me experience I think, and if anything hand covering the back acts like an EQ filling in the hole at 1.5k region

I haven't been using them much but took them out for some measurements which has thrown up some interesting things:

View attachment 301041

When I measure headphones with leather pads I place a layer of foam on the flat plate, otherwise the seal is 'too good' and becomes unrepresentative of the true response. This is supported by my in-ear measurements which show that the perfect seal on the flat plate does not match the lower end response on my actual head.

However in the case of the K245 you can see that rather than just affecting just the bass, e.g. by causing roll-off when seal is breached as is typical, varying the seal tilts the entire response to about 6kHz.

With a perfect seal, which is impossible on your head (unless you're bald maybe?), you get a hefty bass boost and a big dip in the midrange. If you completely breach the seal it tilts all the way up and the response just becomes flat throughout this region. The orange trace is what I started with, and which happened to match my in-ear measurement in bass response and that 1.5kHz dip as well.

That is very interesting. That blue line has the tuck of the -2db filter at 200Hz, and from 300hz to 4K, it tracks HD6xx quite well - that is very promising.

I realize it is a complex interaction and there is no way to be sure until it is measured, but allow me ask anyway - do you think the "leakage" introduced by perforated ear pads can bring the natural response closer to that blue line? That would be a major win if it did frankly - better comfort, better out of the box tuning, better thermal management for the ears - what more one can ask!

The issue clearly is that with such a seal-dependent response, judging preference and designing EQ becomes very difficult. This is what I'm trying currently:

PK Fc 1350 Hz Gain 3.70 dB Q 2.200
PK Fc 200.0 Hz Gain -2.00 dB Q 1.200
PK Fc 7400 Hz Gain -6.00 dB Q 5.000
PK Fc 8680 Hz Gain -4.00 dB Q 5.000
PK Fc 4230 Hz Gain 3.00 dB Q 2.000

First two are the same, the I took a couple more dB off the 7400Hz and 8680Hz filters from before, then I added the 4230Hz to address the measured dip there.

I think it's getting there but, at 6 filters, it's undermining the premise of a neutral open back with enough bass to minimise the need for EQ.

I don't know what the answer is to this unfortunately. An industry standard measurement might help but if the seal variations on the FPC translate to real life usage, it's difficult make a definite udgment of sound quality and EQ recommendations.

I agree. I did stipulate once five filters ought to be enough for any good headphone as well, but If perforated ear pads works as the blue line suggests, then I suspect it would be easier to tune it correctly. I like how they look, and given how portable, easy to drive, and light they are and how sturdy they look, if comfort and tuning can be improved with some ear pads, then I think it will definitely be worth it.

PS. Both HD800S and HE1000v2 has 10 filters each as per Oratory so if this little device can get away with 6, I think that is fine.
PPS. Ordered the perforated pads from Brainwavz. They should arrive in a day or two - fingers crossed.

 

[IAtaman]

PPS. Ordered the perforated pads from Brainwavz. They should arrive in a day or two - fingers crossed.

Got the pads yesterday. They fitted nicely although the installation was a bit tricky. Comfort is much better both in terms of ear fit and heat accumulation. This is now one of the most comfortable pair of cans I own. I can barely start to feel that I have a set of headphones on my head after 30 mins - very happy with them.

Sound wise, I am afraid I am on my own as I got nothing other than my ears to rely on at this stage until I got a pair of in-ear measurement mics or something. Initial impression on how it sounds: the EQ I was happy with before does not sound right with the larger earpads. I will play around a bit and see if I can hone in on a set of filters that I am happy with.

 

[IAtaman]

I have been ABing with 800S EQ'ed to Harman with K245 and landed on below EQ for the time being which sound quite correct to my ears. I am going to do a bit more comparison tonight but I think we have a winner here.

Preamp: -6dB 
Filter 1: ON LSC Fc 30 Hz Gain 2 dB Q 0.7
Filter 2: ON LSC Fc 70 Hz Gain 3 dB Q 0.7
Filter 3: ON PK Fc 1500 Hz Gain 3 dB Q 3
Filter 4: ON HSC Fc 1000 Hz Gain -2 dB Q 0.7
Filter 5: ON PK Fc 8000 Hz Gain -3 dB Q 2
Filter 6: ON HSC Fc 12000 Hz Gain 2 dB Q 1.41

 

[IAtaman]

@isostasy I think I would like to get a pair of in-ear measurement mics. Any recommendations?

 

[isostasy]

I realize it is a complex interaction and there is no way to be sure until it is measured, but allow me ask anyway - do you think the "leakage" introduced by perforated ear pads can bring the natural response closer to that blue line? That would be a major win if it did frankly - better comfort, better out of the box tuning, better thermal management for the ears - what more one can ask!

Possibly, though I think all you need is a less than perfect seal against the head. A fully perforated earpad is adding even more airflow all around. This might reduce bass too much.

I would have thought a hybrid pad which is the same as stock but with velour on the surface that makes contact with the head would be best.

Got the pads yesterday. They fitted nicely although the installation was a bit tricky. Comfort is much better both in terms of ear fit and heat accumulation. This is now one of the most comfortable pair of cans I own. I can barely start to feel that I have a set of headphones on my head after 30 mins - very happy with them.

Sound wise, I am afraid I am on my own as I got nothing other than my ears to rely on at this stage until I got a pair of in-ear measurement mics or something. Initial impression on how it sounds: the EQ I was happy with before does not sound right with the larger earpads. I will play around a bit and see if I can hone in on a set of filters that I am happy with.

Do they not fit loosely due to being a few mm wider than the cups?

I have a pair of earpads that look similar to these but I don't know if they are the same size or even if they are the same material.

@isostasy I think I would like to get a pair of in-ear measurement mics. Any recommendations?

All I'm using is a small electret microphone wired to 3.5mm plugged straight into my laptop's mic input. I don't think you get very good SNR this way but it's evidently good enough for making crude comparisons of headphones on your own head. I've seen these Primo mics recommended and I might get some if I'm more serious about it in future, but for now I've just been using cheap ones from a bulk electronics supplier, I think it was these ones. +-3dB isn't great but then again over 20-20,000Hz not bad and there is no need for perfect or even good linearity anyway.

If you literally want a "pair" as you say that's a bit harder because then you need an interface with stereo mic inputs. This would probably mean something like a Scarlett 2i2 which has 2 x mono mic inputs but I'm not sure how you'd wire things up then. I'm not sure if you need to wire them for phantom power. I'm not electronics savvy enough unfortunately.

 

[MayaTlab]

If you literally want a "pair" as you say that's a bit harder because then you need an interface with stereo mic inputs. This would probably mean something like a Scarlett 2i2 which has 2 x mono mic inputs but I'm not sure how you'd wire things up then. I'm not sure if you need to wire them for phantom power. I'm not electronics savvy enough unfortunately.

If you want to stick to plug-in power with stereo mics, I've used both the Zoom H1n and the Rode AI-micro (with a splitter like this, as the latter can't power a stereo mic from one input only : https://www.thomann.de/fr/soundman_splitter_adapter.htm).

 

[IAtaman]

Do they not fit loosely due to being a few mm wider than the cups?

They have a bit of a give if you like, but I'd not call them loose. Will take a photo tomorrow.

I really enjoy them. They are the top pair in my rotation by "hours on head" metric since I got the new pads . I'll be leaving for vacation soon and these will be coming with me as well.

If you literally want a "pair" as you say that's a bit harder because then you need an interface with stereo mic inputs. This would probably mean something like a Scarlett 2i2 which has 2 x mono mic inputs but I'm not sure how you'd wire things up then. I'm not sure if you need to wire them for phantom power. I'm not electronics savvy enough unfortunately.

If you want to stick to plug-in power with stereo mics, I've used both the Zoom H1n and the Rode AI-micro (with a splitter like this, as the latter can't power a stereo mic from one input only : https://www.thomann.de/fr/soundman_splitter_adapter.htm).

I have no idea. I am literate in electronics but not in acoustics. All measurement I see are stereo so I thought that is what's needed. Plus, maybe my left pinna is a bit bigger or a bit flatter or a bit different then the right one that might be significant in some way or another, so get a pair while you are at it I figured . You gents think a pair will not be necessary?

My plan is to measure HD600 on my head a few times and make that my reference to compare it to other headphones, starting with K245s with Brainwavz perforated pads. I have a few more headphones so I thought maybe I might even be able to build myself a larger set of reference measurements to at least have something to refer to when adjusting tuning.

Those Primo EM25s look good to me. I will order a few and play around with them. On the link you shared, it says Primo suggests the EM258 as a possible replacement for the Panasonic WM-61A. I found Panasomic WM-61A online as well. Shall I get those two, are they better in any way, or maybe more standard?

Dayton Audio also has this iMM-6 calibrated mics. They are like $20. Maybe I can get that and use it with the calibration file it comes with which might make life easier?