General question on Carbon fiber tonearms versus aluminum

noromance

Dolby effectively filtered frequencies (-3 dB at 600 Hz/ -6 dB at 1.2 kHz/ -8 dB at 2.4 kHz/ -10 dB at 5 kHz) resulting in a removal of ambient information. Back in the 80s, we never used Dolby B or C as both sounded worse than the clear and airy unadulterated sound—albeit with tape noise.

Dolby NR does not "filter" frequencies and the result after NR is essentially flat when the system is properly aligned. That requires precise adjustment of Dolby level and bias/eq for the specific tape being used. The prevalence of cheap cassette decks and lazy or misinformed users contributed to Dolby getting a bad rap for filtering highs, which obviously remains to this day. But it is really unwarranted. Both Dolby B and C remain very, very effective when properly used. I still have an outboard Nakamichi NR-200 and on the rare occasion that I play a cassette I'm amazed at the fidelity of mix tapes I made decades ago.

@cleeds Thanks for pointing that out.  The Dolby equalization curve concept is no different than the RIAA concept we all live with when we play vinyl.  There is a Dolby pre-equalization of the music and a post equalization when playing, which reduces hiss.   RIAA pre-equalization and post equalization reduces surface noise.   

Since I wrote that first post, I realized I forgot about Titanium.  My first high end tonearm, a SME III, had a titanium tube, as do several tonearms today.   So, we have Carbon Fiber, Aluminum, and Titanium to consider as tonearm materials which can influence sound.

spatialking

... The Dolby equalization curve concept is no different than the RIAA concept we all live with when we play vinyl. There is a Dolby pre-equalization of the music and a post equalization when playing, which reduces hiss ...

Dolby and RIAA are similar but different. RIAA is an EQ curve while Dolby is a sliding band compression/expansion system. It's that sliding band that makes alignment to Dolby reference level so critical to Dolby working properly.