Sennheiser HD600 - natural target V2 (Patreon)

I settled on V1a as base for my further adjustments and came up with V2, in reality this is already V8 as I have spent the last 2 days to optimise eveything. I thought I had a great improvement and wanted to post something already yesterday while finally discovering that the overall balance was simply not right. That's if one tries to stick too much to graphs instead of listening. This version should finally have the overall balance way more correct than all previous versions. It may not appear as much of a difference in the graph, but the difference is very noticeable when listening. I added a correcting filter at 1khz which gets the balance more correct as V1 simply had too much bass and too little mids. I readjusted all other filters to have an as correct as possible sounding spectrum when compared to the speakers. I am really close now, but there may be nuances which will still need some adjustment when I finally receice the KH80, I will need to perform another longer listening session in a more dampened room to really listen to "pink noise" and not something too altered.

Here is V2 compared to V1a in green overlaid with the reference spectrum:

I am not following my reference spectrum that precisely anmore and just use it as rough guide now, following that line too strictly messed everything up and I was not able to get the entire image right. I concentrated too much on some details but losing the whole spectrum out of sight which resulted in some balance errors.

You can also notice that I follow Oratory1990's OptimumHifi (blue) target way closer up to 2khz, this is where it obviously starts to drift apart but this part actually give the sound the necessary realism. If upper mids and especially treble do not have the correct balance it will never sound correct. First of all treble must be smooth with no gaps or peaks, and then it must have the correct amount compared to the entire rest, this will influence a lot how the overall sound will be:

This version may appear bright to some, but actually it is exactly how I perceive treble amount from speakers as well. I can still hear up to 16khz and then it becomes dead. I checked it with tone loudness matching from speakers and headphone and I was simply too soft in my previous versions, I could barely hear 15khz in my previous versions while from the speakers it was way louder, therefore I had to readjust the entire treble balance to get it closer to what I hear from real life as well. The HD600 stock will sound way more grainy and veiled because it is lacking a lot above 13khz, while having too much at 12.7khz at least for me. I always hear 12.7 louder within a spectrum also from speakers and I had to readjust this to a similar degree for V2 You should test this on your own to get the best possible results and then re-adjust those filters. Here the HD600 compensated for my new target:

To my surprise I even perceive the HD560S as more neutral now than I heard it before, but approaching this target towards speakers somehow changed my percpetion of what I regard as "neutral" and correct, and it would seem that my target definitely has more emphasis on the region at 6-8khz than most other targets, but without that boost the sound would be not close to what I perceive as natural sounding. Thus right now I would probably choose the HD560S as best affordable neutral allround-headphone for those wondering. The HD560S still has too much response around 6-9khz, but I would definitely regard it as more realistic sounding than the HD600 let alone the HD650 which is even darker. I may have to revisist the Sundara or some others which appeared too shouty for me before.

Listening to the HD600 with V2 compared to the HD560S they sound pretty similar but the HD560S is lacking that smoothness and refinement, and those always claiming the HD560S having a better sound stage etc, close to the HD800S blah blah, with V2 the HD600 sounds way more spacious and 3D to me than any other headphone let alone the highly praised HD800S especially for its sound stage sounds just off now. I cannot hear any more detail neither any better imagging. Here you can see the HD800S also compensated for my current target:

It has way too little mids while those peaks at 7 and 10khz are totally masking all details in treble above which is missing by several dB compared to what I personally perceive as neutral. I am still wondering why this expensive headphone became so popular, I simply cannot hear any real advantage over any other headphone.

Please let me know how this works for you. If you hear some weird peaks, try moving the headphone around a bit. I am basing my adjustments on heavily averaged measurements I did with various headphone positionings, thus trying not too bake a single position too much into my tuning. Thus it should still sound to some degree correct if you place the headphone differently, but any change in placement may emphasise different parts of the spectrum, this is simply how headphones couple with a human ear and unfortunately with every ear to a different degree. But I think I have the right balance now more or less and will just need to tweak some finer details from now on. The overall sound won't change much from now on and will be rather influenced by the given unit, pads, headphone positioning and listener's ears etc. Thus all my fine tuning I can perceive as improvement for my own, may be hardly noticeable to others as real improvement. But more important is that the overall balance seems correct now. I will talk about all filters in detail, what they do and how they may be optimised for someone else in my Hifi-level section for those interested. Neverthless I need to know if this version is perceived as an improvement for you as well. I need this feedback in order to know how others are perceiving the sound and to which degree it may be different. Keep in mind that also the ear canal geometry will influence the sound a lot, I noticed that with overears as well, before and after ear cleaning there was a noticeable difference, therefore it is close to impossible for me to get perfect results for everyone and I am already fighting to get it 100% right for myself.

After your feedback I will try to get a Qudelix 5K setting next, so please let me know what you think.

Update: added a slightly improved version 2.1. I let my son hear both and he also thought the new one is better, I also think my recordings sound smoother like this, therefore I am wondering if it's an improvement for you as well. Notice how those tiny adjustments can give such a big benefit. Although I seem to be departing from my original reference spectrum more, I definitely get a hearable improvement which makes me think that you just cannot believe any graph at all.

Black is V2.1, blue V2 and grey the refernce spectrum:

Update 2:

I don’t want to bother you with all those micro adjustments I am doing but I managed to get a quick Qudelix 5K setting based on 2.2 which I may improve a bit more before posting a final version, although from now on it will be only some tiny corrections which may not even be noticeable to others. For the Qudelix 5K I needed 2 additional correction filters and did some further adjustments to get the sound close enough to the desired result. The responses deviate a bit but I think it’s still quite decent.

I need to post it with 3 separate images as I have no way to compose them on my phone because I am already laying in bed and listening to some music with the new setting: