booster-t
04-16-2017, 06:53 PM
OK ... looking for some feedback ... I have been amassing a fairly large collection of SACD-R disks. That average around between 3g and 4g in size. Why you may ask? The multi-channel sounds great when played through my home audio system. I am a Mac user, so I can use Audirvana to do so. The problem I have is that ONLY Audirvana (well, JRiver also) can play the ISO disks. Using a small free utility, I can covert this ISOs into dsf files. They retain the same audio as the SACD but now are individual files that can be played using a small app called VOX. Audirvana can also play them so that's not an issue. The problem is that the individual files wind up being about twice the size of the ISO. I can convert the dsf files to FLAC however and retain the multichannel sound. That allows me to play them on other apps.

So here's the big question. Most of these files are either 88,2, or 192 kHz. If I reduce the 192 files to 96KHz, their size is halved and I'm back to the same size as before. Listening is the key. To my nearly 70 year old ears, I can't detect a difference between the higher bit rate and the lower bit rate. Am I Ok to reduce the bit rate then? From a purist perspective, Suspect I shouldn't. But as Mr Spock once told Captain Kirk --- a difference that makes no difference is no difference.

Thoughts? Comments? Suggestions?

Thankds

Stephen

bobtheknob
04-16-2017, 09:36 PM
My hearing is in great shape (unless I'm talking to my ex....), and I have never been able to discern any audible difference between 88.2, 96, or 192 kHz. I mean, after all, the limit of human hearing is around 48 kHz, so how could we hear any difference above 88.2? Yes, you are losing some digital content by reducing, but only your dog will notice.

(Per your suggestion a few months ago, when I was still posting SACDs, I changed my conversion rate from 96 kHz to 88.2 kHz, since that is proportionately aligned with the SACD's native 2822.4 kHz rate, and afterward, I never once ever received a single complaint from any of my "customers" that they had noticed any reduction in quality.)

ROKUSHO
04-17-2017, 12:50 AM
i can tell the difference. the higher the number, the better. period.

JHFan
04-20-2017, 12:30 AM
Honestly it's a placebo effect. People typically hear a perceptible difference if they know already that something is inherently higher bitrate, or uncompressed vs compressed, or whatever the case. People have upsampled content to edit, then downsampled back to its original 44100. I've never done such a thing when editing and no one has ever said anything of it.

DAKoftheOTA
04-20-2017, 05:51 PM
:this:

Jarilo
04-21-2017, 03:37 PM
It is not the tone frequencies.... In real life you'll get very complicated shape of signal that should be coded. Bitrate largely tells you accuracy of encoding-decoding. When you compare sound
dont listen to high frequencies, listen to what is going in musical phrase, did you understand what it means? It is good or it is "wow"? I get the differences. But in proper home audio setup (decent source, good separate DAC, good coax and audio cables)... It's difficult to believe your Mac's accuracy may take nuances of hires records. If your SACDs stay with you in vault, do some compare and if you dont hear differences - compress!
Pay attention that different apps may give you different sound realization. That is math algorithm after all - and there is plenty. Sometimes I get differences in sound of the same app in different versions.
My ears are not the best as well(after 50)

booster-t
04-21-2017, 08:06 PM
Thanks for the comments everyone ... especially Jarilo ... I did some sampling (pardon the pun) using different applications. I am well past 50 <sigh> and I can say that I didn't hear sufficient differences between the files generated by the algorithms ... I found XLD to be the best in rendering a 24/96 or 24/88.2 version of the dsf files. I have the original SACDs backed up so I can re-rip if a better application comes along. On my iMac, all the output is converted to PCM so the only difference I can discern is what I would call "depth of field" in that the music sounds more "open". When playing the SACDs using Audirvana through my sound system, of course surround sound is better than two-channel PCM. But that is the also a different listening experience. One side note: I saved myself about 650g this way.