TP-027, Jerry Garcia / David Grisman wins a Writer's Choice Award from Myles Astor of Positive Feedback Online
Unfortunately I don't have published measurements as I have been redoing my lab setup and I'm without some of the necessary gear for a detailed test at the moment. With the Flux Magnetics extended response head (which is designed to give bottom end response at 30ips of -3dB at 20Hz) I would say the max would be maybe 20Hz to 30kHz at 15 ips. 30Hz-30kHz is the advertised response of a stock RS1500. It has heads that are compromised in length to better accommodate 7.5 ips playback as well as 15 ips playback...........These figures would apply pretty well to most tape machines of similar vintage, like the Otari MX-5050. Older machines like the tube output Ampex decks have heads with more limited top end. An old 300 or a consumer type 900 series machine with stock heads might only get to 12K or 15K on top.
I'm wondering if the revised tape wrap's main benefit is reducing scrape flutter.