Dynamics Comparison

[Κώστας Φ.]

Μία σειρά άρθρων του audioholics, σχετικά με τις διαφορές στη δυναμική περιοχή μεταξύ των διαφόρων format.
Υπόψην πως δεν πρόκειται τόσο για αυστηρά "τεχνικά" άρθρα όσο για άρθρα γραμμένα απο τη μεριά του χομπίστα που το ψάχνει λίγο παραπάνω.
Μου φάνηκε αρκετά ενδιαφέρουσα δουλειά.

Part 1 - Dynamic Comparison of CD, DVD-A, SACD

"The CD is the most "compressed" (average signal amplitude higher in comparison to the peak) and DSD the "least" compressed. This means that if you adjust the relative levels of the three recordings such that the relative "energy" across all three are approximately the same, then the peaks and transients in SACD will be "higher" over DVD-A, which in turn will be higher than CD.

The differences are hard to see on this web page because I have shrunk the waveforms, but on Cool Edit they were quite obvious, and represents around a 2-3dB difference, which is significant enough to be audible. This difference was also noted empirically by me during recording, as I had to lower the gain for the CD and increase the gain for SACD.

If this difference is "real", as opposed to an anomaly in my equipment, then it could explain why some people don't like SACD compared to CD or DVD-A. The slightly lowered sound levels, if not compensated during the listening process, will cause SACD not to sound "as good" compared to CD or DVD-A.

The better dynamic performance of SACD would also explain why some people prefer SACD, as they probably notice the slightly higher dynamics.

The results are interesting indeed, even though I would caution against over-generalizing them into conclusions about each format. Remember that the results may not be applicable beyond a single title and the constraints of my equipment."



Part 2 - Dynamic Comparison of CD, DVD-A, SACD

"Well, I was hoping merely to confirm that the DSD recording has higher dynamics than the PCM recordings on CD and DVD-A, and I did manage to confirm my previous observation. The differences between the dynamics can be due to many reasons, the most likely being differences between the players in their ability to reproduce dynamic transients accurately.

However, I did not expect to see clipping on the CD and DVD-A recordings. This could either be a fault in the transfer, or in to D/A conversion stage, but it's quite interesting that I was able to observe clipping on two separate players (the Sony playing CD and the Panasonic playing DVD-A)! This clipping may be the reason why many people feel PCM recordings sound "edgier" than LP or SACD if it is prevalent during playback!"



Part 3 - Dynamic Comparison of CD, DVD-A, SACD

"Conclusion

So it now looks like the differences in dynamics may be more fundamental than differences between players. Given that both DVD-A and SACD transfers come from the same analog master, the differences can now be narrowed to either the transfer process or the underlying format.

Late breaking news: After I wrote an article exploring the ability of various players in handling 0dBFS+ levels, I realised there is potentially a much simpler explanation, and it's to do with the players' inability to handle levels above 0dB FS. Given that neither the Panasonic DVD-RP82 nor the Denon DVD-2200 handle 0dBFS+ levels, the very slight reduction in relative dynamics could be due to this limitation (assuming that the DVD-A is recorded with digital samples peaking at 0dB FS). The reason why the SACD is not affected is the lower level of the recording (-6dB)."


Part 4 - Dynamic Comparison of LPs vs CDs

"Conclusions

It appears that the vinylphile claims are not as outrageous as they seem: LPs do have a usable dynamic range far greater than the measured dynamic range would suggest, and LPs consistently have higher relative dynamics over digital formats. But it is also true that LPs have higher distortion levels which translate to ultrasonic frequency harmonics.

The question is: is the higher relative dynamics of LPs an indication of higher accuracy, or are LPs exaggerating transients and dynamics? I'm not sure, and I would welcome comments.

If LPs have higher distortion and are exaggerating dynamics, it may explain why the apparent "benefits" of LPs translate even into LP recordings, and potentially explain why LPs of digital recordings sound better than their CD equivalents."


Part 5 - Dynamic Comparison SACD vs CD

"Conclusions

First of all, regardless of whether Café Blue was originally recorded in analog or low-resolution PCM, it still doesn't change the observation that it is an excellent recording. Perhaps it is a useful reminder to us just how good 44.1kHz 16-bits can be, especially when all 16-bits are used and dynamic compression is avoided.

The differences between the CD-R of the original release and the remastered CD layer also highlight the benefits of careful remastering using the latest technology can bring even to digital recordings.

In that case, what accounts for the audible differences between the CD and SACD layers? I'll leave it up to the reader to draw his/her own conclusions, but here are some possible reasons:

• There are no differences between the CD and SACD layers. Any observable differences are purely a figment of the listener's imagination
• The differences are due to the relative accuracy of the player in reproducing PCM vs DSD.
• The differences are due to the CD layer clipping or exhibiting 0dBFS+ levels.
• The differences are due to the SACD revealing more of the benefits of the remaster that was possibly done using high resolution processing.
• The differences are due to the DSD ultrasonic noise somehow affecting the playback chain or our hearing.
• The differences are primarily due to the relative level difference between the layers (the SACD layer is on average around 0.7dB louder than the CD layer which would be just audible)."

Στη συνέχεια το ψάχνουν λίγο παραπάνω με τις 0 dBFS στάθμες και την υπέρβαση αυτών στα ψηφιακά συστήματα (αλλά δεν τα έχω διαβάσει ακόμα :happy_8: )...
Τα αντίστοιχα άρθρα θα τα βρείτε εδώ κι εδώ.