I agree. I love the spirocores on this bass. I tried the stock which where very articulate but very little thump. Then tried obligatos which were on my old eub. They feel and sound very good to my ears. A growly tone with fair punch but they dont work well with the mags. Then i tried pirastro permanent since i liked the obligatos so much. Btw the obligatos are very easy to bow. The permanents had mote of a thumpy sound and bit brighter but i really missed rhe growl of the obligatos. They also bow really easy. Finally i decided to try spiro mittels expecting them to be to bright but definitely growly. For the first couple days they were fairly bright but not as much as i had expected. This reminds me that i did try ns traditionals as well but they had a very bright top end with a thumpy low end. One may say they sounded scooped. Just not enough mids to cut through a dance rock band as i experienced. Yeah, i also do everything from jazz to pop so i have to take cutting through a fairly loud band into consideration. If i was doing strictly supportable jazz the permanents probably would have been fine. So back to the spiros. They have midrange tone that cuts and growls far better than the other strings. More along the lines of my fav obligatos but punchier. In fact the e and a string are quite remarkable. One thing to note is that the mittels are higher tension than the obligatos and the stock strings but i dont have an issue with it. If you are used to the stock strings it will take a bit to get used to. I simply prefer a beefier string so i can dig in more. The only real negative i found is that like mentioned above the spiros are quite challenging to bow. In conclusion for a growly string and my wide range of styles this is the string for me. If i must bow more in the future ill swap back on the permanents or obligatos. Hope this helps.