catman Posted July 15, 2017 Posted July 15, 2017 (edited) G'day all, in a thinking mood about RIAA equalisation this afternoon I had a read of this interesting Wikipedia article on the subject of RIAA equalisation: https://en.wikipedia.org/wiki/RIAA_equalization There is a lot in it, including the rationale behind various 'tinkerings' over the years. The comments regarding the 20 Hz IEC amendment are 'interesting' and show that it was possibly a 'not so good' idea in the first place and wasn't particularly popular with manufacturers, although I have a 'gut' feeling that the NAD PP2e includes it. On the other side of the spectrum, the question of the 'Neumann' 50 KHz roll off is likewise interesting but honestly I don't really see any merit for the 'ERIAA curve'. The 'ongoing' RIAA treble roll off aspect is seemingly ignored by many manufacturers who use the very popular and easy to implement feedback type RIAA equalisation around your typical op amp stage, as the typical non-inverting op amp stage cannot provide true ongoing treble roll off due to the nature of the non inverting op amp amplifier stage. However, in the end does it really matter? In all honesty, I'm not overly sure! Having heard and built many different phono stages that employ all these different approaches to RIAA equalisation, purely on the basis of listening, all I can say is that all these different approaches have the potential to sound great. I will say though that my very best sounding phono and 'dynamic' stages are 'probably' those employing hybrid (part active and part passive) or full passive RIAA equalisation. All because we like listening to records! Regards, Felix. Edited July 15, 2017 by catman Spelling.
audiofeline Posted July 18, 2017 Posted July 18, 2017 I was not aware that there were different RIAA curves, I naively thought the standards were standard by the time they were universally adopted (at least in audio). Now it appears that the standards are about as fixed as IT standards are which have been fiddled with by Microsoft.
Roumelio. Posted July 18, 2017 Posted July 18, 2017 (edited) The RIAA standard was commissioned before all this nonsense about loudness. SEE: Loudness war When the RIAA equalization standard was written the inherent bandwidth limitations of the recording equipment and cutting lathe imposed their own ultimate upper limitations. Inherently it was near impossible to produce any noise above 20khz and not much over 16khz Most all music except for certain Motown and jukebox music was also designed for 60db due to the limitations of tape and record players. An issue with the recording process and cutting lathes for records led to frequencies above 20khz to be cut, as well as most of the frequencies nominally below 30hz (which most people can't hear when there's so much going on anyway.) Modern music has far greater bandwidth than this (although more bandwidth is not inherently always beneficial). The so called eRIAA now exists. The "enhanced RIAA" attempts to compensate for the changes in frequency response curves and loudness, although as you are beginning to find out this is also not something that is beneficial. If you listen to music now that is normalised and brickwalled for listening spaces somewhere in the 75-85db range you begin to realise just how terrible modern music can be, see the link as above. At this point one steps back and says well "Ill be darned..." Maybe those old guys that run vintage class A amplifiers were onto something about why they sound better and maybe its not just about THD or the ultimate amount of loudness one can achieve in music. People are starting to realise as they become more discerning listeners that music without any peaks in the natural wave form sounds like crap and now we have all this conversation about not "brick walling" music which is forcing studios to get rid of normalisation and compression to begin with and so groups like Daft Punk came along and said "we're not going to do all this loudness normalisation and require all of that compression" and came out with the 2013 Grammy award winning Random Access Memories (among others...) Edited July 18, 2017 by Roumelio.
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