Hello!
I have two HD599 pairs, which I enjoy quite a bit.
I also have a pair of HD560S, which I tried to like but to no avail..
So, I went ahead and swapped the HD560S 120Ohm drivers with the 50Ohm drivers from one of my HD599 pairs.
You just unscrew the baffles from both pairs, desolder the drivers and then solder and screw the HD599 ones in the HD560S housing.
NOTE: You can use the HD559 as a 'donor'. They're using the exact drivers/baffles.
Here you see the HD5699 'hybrid'!

Basically it looks like a typical HD560S.
Until you put them on and notice that something HAS audibly changed.
---------
From here on I attest my personal opinion (and rant), so please bare with me:
The 'HD5699' doesn't sound 'sterile' and/or flat anymore..
HD560S, while it's measuring good, I think it lacks body and impact. It has soundstage and is not grainy, I'll give it that.
But some important parameters for real music enjoyment, namely body, pace and impact, were missing.
When you create a headphone simply to look good on papers, based on whatever current 'target response', you might end up with a 'flat' sounding pair.
Sorry Sennheiser but this is still an HD5xx series headphone and folks enjoy them for their laid-back, full-bodied character that gives life to music.
For uber-technical 'neutrality' and 'follow the graphs' orthodoxy, there are myriads of other models out there. I have an HD600 for that I think..
My point is, who cares if it measures great but it hurts your ears after 10 minutes, or you need a graphic equalizer to enjoy music?
-End of rant-
-----------
How does this 'hybrid' sound?
In a nutshell, a bit better than the good old HD599.
Probably due to the slightly different shell of the HD560S (wider grill holes and no plastic overlay).
It gives more focus and impact to the sound.
Lows are better articulated and go deeper, mids keep their presence but are better controlled and highs become less grainy.
Soundstage increased a bit, both in width and in height.
Separation of instruments and sense of depth also improved.
Maybe, it has to do with reduced resonances resulting in better driver control?
I don't know, but the result is good (to my ears at least).
So folks, if you enjoy the sound of your HD599/598 but feel your HD560S falls short of your expectations, you might want to give the 'HD5699' a try.
You can always revert back to stock, if you are not impressed.
Have fun and thanks for reading!
I have two HD599 pairs, which I enjoy quite a bit.
I also have a pair of HD560S, which I tried to like but to no avail..
So, I went ahead and swapped the HD560S 120Ohm drivers with the 50Ohm drivers from one of my HD599 pairs.
You just unscrew the baffles from both pairs, desolder the drivers and then solder and screw the HD599 ones in the HD560S housing.
NOTE: You can use the HD559 as a 'donor'. They're using the exact drivers/baffles.
Here you see the HD5699 'hybrid'!

Basically it looks like a typical HD560S.
Until you put them on and notice that something HAS audibly changed.
---------
From here on I attest my personal opinion (and rant), so please bare with me:
The 'HD5699' doesn't sound 'sterile' and/or flat anymore..
HD560S, while it's measuring good, I think it lacks body and impact. It has soundstage and is not grainy, I'll give it that.
But some important parameters for real music enjoyment, namely body, pace and impact, were missing.
When you create a headphone simply to look good on papers, based on whatever current 'target response', you might end up with a 'flat' sounding pair.
Sorry Sennheiser but this is still an HD5xx series headphone and folks enjoy them for their laid-back, full-bodied character that gives life to music.
For uber-technical 'neutrality' and 'follow the graphs' orthodoxy, there are myriads of other models out there. I have an HD600 for that I think..
My point is, who cares if it measures great but it hurts your ears after 10 minutes, or you need a graphic equalizer to enjoy music?
-End of rant-
-----------
How does this 'hybrid' sound?
In a nutshell, a bit better than the good old HD599.
Probably due to the slightly different shell of the HD560S (wider grill holes and no plastic overlay).
It gives more focus and impact to the sound.
Lows are better articulated and go deeper, mids keep their presence but are better controlled and highs become less grainy.
Soundstage increased a bit, both in width and in height.
Separation of instruments and sense of depth also improved.
Maybe, it has to do with reduced resonances resulting in better driver control?
I don't know, but the result is good (to my ears at least).

So folks, if you enjoy the sound of your HD599/598 but feel your HD560S falls short of your expectations, you might want to give the 'HD5699' a try.
You can always revert back to stock, if you are not impressed.
Have fun and thanks for reading!
Attachments
Last edited: