...Percentage wise, how much better did it sound?
I've found that the results of demastering my music tracks to be all over the map: some improved dramatically...and others, not as much. But I've found that over 90% of my recorded music library is noticeably improved using this technique--to the point that I generally demaster (in some way) virtually every newly acquired CD that comes into my library.
SACD disc tracks cannot be demastered (i.e., ripped DSD files), and DVD-As and Blu-Ray PCM music multichannel discs are sometimes okay as-is, or sometimes
heavily clipped by the mastering people in order to make the tracks sound louder directly off the disc. Running
Clip-Fix, then
Normalize... on these generally reconstructs most of the clipped peaks and returns the overall track loudness back to as-recorded levels (i.e., near zero on the ReplayGain scale), and eliminates the harshness and induced odd-order harmonics due to the clipped peaks from the released mastering effects. Demastering processes use the inherent precision of numerical methods, not the inherent fuzziness of analog reconstruction processes.
I've applied these processes using
Audacity freeware to many thousands of music tracks, mostly ripped from older used CDs--but also for a handful of vinyl rips, which are usually plagued by much noisier conditions, but sometimes have a much higher dynamic range remaining particularly on popular recordings made since 1991. Some older recordings are just not available on CD (digital format).
The best results always are gleaned from the best quality CD tracks, which are also usually the oldest CD versions with the highest retained dynamic range, and were generally released before 1991. These are also the least expensive to buy used on outlets like Amazon Marketplace and Discogs. These discs generally sell below $6 USD/disc nowadays, but as recently as four years ago, these prices were below $4/disc (i.e., the shipping & handling cost only). A little digging on Discogs and the DR-Database to find the highest retained dynamic range disc version available is the ticket to much improved listening pleasure.
On a time-spent basis per disc, I can now stay slightly ahead of the playback of the tracks ripped from CD while doing initial (coarse correction) demastering of each individual CD track using
Audacity in real time. But note that I've had lots of experience demastering tracks--about 10 years and perhaps 25-30 thousand individual tracks completed, probably in excess of 2000 hours/year spent in demastering music tracks.
For popular music genres, generally each music track must be demastered individually, while classical music discs generally can be demastered using a single demastering EQ curve (after declipping, which is done first via macro--called a "chain" in
Audacity). Jazz discs are somewhere in between classical and popular discs in terms of using single custom demastering EQ curves for the entire disc or by individually derived EQ tracks for each track.
But I strongly recommend
getting the SPL and phase response of your loudspeakers under control first, since this has such a strong effect on the subjective listening results, particularly when using horn-loaded loudspeakers in getting rid of the all-pass phase growth of the loudspeaker's crossover filters and time alignment of each loudspeaker "way", This is basically to achieve minimum phase loudspeaker response first before demastering. Otherwise, you'll be finding yourself re-doing your demastered tracks again to rebalance the resulting bass response, which is >3 dB more subjectively apparent on minimum phase loudspeakers in my experience.
Chris
