We've put together a comparison of these two impressive headphones Sennheiser HD 660 S vs Beyerdynamic Custom One Pro Plus. Based on our rating, HD 660 S has a total rating of 8 out of 10 vs 7.5 out of 10 for Custom One Pro Plus.
The Sennheiser HD 660 S is better headphones in this comparison. Check Sennheiser HD 660 S price