[Backsplash7]

Thanks for the suggestions, but being an MOT cable-maker myself I'm pretty well-attuned to how different combinations of wire and connectors can affect capacitance, inductance, impedance etc.
I agree with your suggestion that connectors using different metals in terms of capacitance (not conductivity as you state - you can't accurately measure that in connectors) can be beneficial as well as detrimental to the entire cables' sonic characteristics.
I don't agree however that 'pure-silver' as per your reference exists in cable form. I don't want to refute any other cable maker's claims but anyone selling silver wire really ought to state that it's either a silver/copper alloy or copper containing a percentage of silver and other metals. Pure silver is far too brittle to use in 'pure' form and in any case the electrical current of a cable travels over the surface of the conductor wire and not through it, so claiming the use of solid or 'pure' silver is pretty null and void anyway - whether it's 'pure' silver or SPC the current flow characteristics would be exactly the same for both.

Well, I'm not going to have an argument about cables and wires, I'm just making suggestions for things that might help bring out more performance.

Replacing the foam behind the driver with matching foam type and density, I have found to help with other older sennheisers. And in the one case, rather than going for a thinner and less dense filter foam in front of the driver, which I commonly see as a recommendation but makes things worse for me, I tried using a denser one, which I was told was closer to the old original ones from way back, that made a positive impact with no tradeoffs

 

[Chuck Dee]

Well, I'm not going to have an argument about cables and wires, I'm just making suggestions for things that might help bring out more performance.

Replacing the foam behind the driver with matching foam type and density, I have found to help with other older sennheisers. And in the one case, rather than going for a thinner and less dense filter foam in front of the driver, which I commonly see as a recommendation but makes things worse for me, I tried using a denser one, which I was told was closer to the old original ones from way back, that made a positive impact with no tradeoffs

That definitely makes a difference and I think a lot of attention was spent by Sennheiser to use that as the primary 'tuning' aspect of the HD5/6 driver design.
I also found that placing different and varied shapes of foam within the void that's created by the HD5* series headphone shells has a significant impact on bass tuning. With foam in place it speeds up the (attack) 'slam time' exponentially. Presumably due to transients being absorbed and not reverberating around inside the enclosure. I think this is the principle behind the HD265 enclosed design too. The whole shell is foam-filled making it incredibly bass-heavy!

The shell on the left is a stock HD565 with HD565 driver. The one on the right is an HD565 shell with an HD650 driver and a foam insert.

HD265 shell. Foamed up to the hilt!

 

[Backsplash7]

That definitely makes a difference and I think a lot of attention was spent by Sennheiser to use that as the primary 'tuning' aspect of the HD5/6 driver design.
I also found that placing different and varied shapes of foam within the void that's created by the HD5* series headphone shells has a significant impact on bass tuning. With foam in place it speeds up the (attack) 'slam time' exponentially. Presumably due to transients being absorbed and not reverberating around inside the enclosure. I think this is the principle behind the HD265 enclosed design too. The whole shell is foam-filled making it incredibly bass-heavy!

The shell on the left is a stock HD565 with HD565 driver. The one on the right is an HD565 shell with an HD650 driver and a foam insert.


HD265 shell. Foamed up to the hilt!

I don't know whether you have any of the older 500 series that came before the 5x5 lineup, but getting the foam right in the back of those is very tricky. For the 540 I ended up with the right type of foam, but I can't find it anywhere in the correct thickness, which I guess must be 1-2mm, but 6.25mm is definitely overdamped, but removing it sucks out most of the bass presence. How I wish spare foam parts were more available for all these older models!

 

[Hofy]

That definitely makes a difference and I think a lot of attention was spent by Sennheiser to use that as the primary 'tuning' aspect of the HD5/6 driver design.
I also found that placing different and varied shapes of foam within the void that's created by the HD5* series headphone shells has a significant impact on bass tuning. With foam in place it speeds up the (attack) 'slam time' exponentially. Presumably due to transients being absorbed and not reverberating around inside the enclosure. I think this is the principle behind the HD265 enclosed design too. The whole shell is foam-filled making it incredibly bass-heavy!

I really need to get out my HD565 and HD5franken5 and listen to them again and compare to my current favorite HD560S.