I bought a headphone aftermarket cable for my Sennheiser HD800s and yes the cable made a noticable imporvement.
You cannot buy another of one like mine whic hwas a limited run from a small cable maker.
But the major brands should be able to do the job.
on TheCableCo site Cardas has earphone cables available with the correct ends for the Sennheisers.
Other brands may also be available with the Sennheiser ends.
PS My HD800s headphones took a LONG time to break in fully.
You cannot buy another of one like mine whic hwas a limited run from a small cable maker.
But the major brands should be able to do the job.
on TheCableCo site Cardas has earphone cables available with the correct ends for the Sennheisers.
Other brands may also be available with the Sennheiser ends.
PS My HD800s headphones took a LONG time to break in fully.