There were the "great ABCDs" of the brother acts: The Allens, The Bolicks, The Callahans, and the Delmores (I should include the Dixons), all fine duets, with a great range of musicality and singing styles. Perhaps the smoothest-sounding, vocally, were Bill and Earl Bolick, "The Blue Sky Boys", with harmony arrangements like sorghum molasses dripping from a gourd spoon. Instrumentally, the Allen Brothers were the most raucous, while the Callahans and the Delmores were pushing the virtuoso flatpick style with lots of verve. But there was something new and special about the sound of Bill and Charlie Monroe. Many have mentioned the blazing speed they brought to the music – to me the most distinguishing aspect of their sound was the drive they gave to the songs, a feeling of ever-leaning-forward, while still keeping one’s balance – like a runner approaching a finish-line tape. Despite their speed and drive, their songs never sounded rushed – there was that ever-present element of control which resulted in such a polished performance. Record log sheets from the Victor company confirm this aspect, and show that they were able to cut ten "sides" or songs in the space of half a day, all apparently, on the first take. To anyone familiar with the recording regimen pertaining today, this fact alone would be considered astounding.