These strings, I find, are the ideal set for my Bassix acoustic/electric upright bass; tuned to orchestra rather than solo pitch they are flexible, warm and hold their tuning well. To my ear they sound mellower than the Dominant set previously used, although these are great strings too. I have not bowed the Spirocores, but for fingerstyle they have a great feel and sound. Amplified or acoustic, they have a true double bass timbre. Thomann, as always, posted them very quickly and they arrived at my home in the UK three days after ordering - quicker then some domestic orders!