And so, I started listening to the standard Oratory equalizer, it seems in principle not bad, but something is wrong, I decided to compare what is so magical in the frequency response of the HD 668B, and I found a clear difference, this is a hole at 3-4k, Solderdude has about such a failure is described as “laid back, sweet”, well, I added a filter something like PK 3.3K -4 dB Q3, well, it seems to be what I like, but somehow not quite again, in some way degree too much.
And today I decided to measure them, albeit with a microphone on the laptop screen, but it should have shown the difference between the channels and something else, and I also decided to measure them immediately with the Oratory equalizer (08.2023).
Well, this is the imbalance I got: the 2.6K - 3.9K areas are up to 5 dB more on the right channel (exactly the area that I had a lot of), and on the left channel the 4K - 6.5K areas are up to 3 dB more, the rest seems to be approximately in balance.
I decided to correct this difference with a channel-by-channel equalizer, the second picture is what came out in the end, well, I want to say it sounds better, I tried turning these equalizer bands off and on in A/B format and the option without them sounds crooked in terms of stereo, but with filters It doesn't seem ideal either. And now you don’t need a 3.5K filter, because... I removed this frequency in one channel and now it sounds normal. I also want to say that before I saw the imbalance on the graph, I heard that in a familiar track I heard, let’s say, a clicking sound in only one channel, although before it seemed to be in both.
In general, I expected, of course, better quality from Sennheiser, which asks $200 for plastic headphones, seemingly for sound, because I can get HD 599 with the same chassis for $130.
P.S. The frequency level below 1K and above 7K on the graphs is slightly different, but I think this is not so important, this is due to the huge leakage, different pressure levels and positions.
P.P.S. I took a closer look, in all measurements the area of 7.5-11K in the right channel is 1-2 dB larger, I’ll also try to remove this
P.P.P.S. And the right channel has less bass in all measurements, but it’s not so obvious by ear, but there seems to be something like that