HDCD & FLAC conversion, what am I listening to?

[WAD62]

Rabid1981 started a thread about unknown HDCDs (cheers mate you triggered a tiny little LED at the back of my cranium). In which he mentioned 'Let it come down' by Spiritualized.

I have an Audiolab 8000DAX which is HDCD compatible, and I recall that this was one of the very few CD's in my possession that actually triggered the HDCD LED. I can't remember the others but that's going to be another saga, I'll check the available lists.

I've ripped all my CD's to FLAC about 18 months ago (and have only been playing FLAC since), and had completely forgotten the HDCD thing, so I immediately checked my FLAC files for the album, all 16bit, and when played back through the DAX, no little red light.

I use dBpoweramp, and after scratting around on the forums for a while I found a thread on the very subject;

By default HDCD is ripped to 16bit(and 44.1k as everything is here), however there's a HDCD DSP plugin (don't you love abbreviations) which must be manually applied after ripping. Standard CDs are left as 16bit, whereas HDCDs are output as 24bit, not slick but workable.

So I now have 2 versions of the album in FLAC, one 16, one 24bit, for side by side comparison.

One interesting (well quite interesting) thing is the difference in ReplayGain values, the 16 bit is -9.5 dB, the 24 bit is +6 dB, a product of compressing HD onto a CD apparently. As I use ReplayGain for playback the comparison volumes are equal.

In comparison there is a very subtle, but noticeable, improvement it the sound on the 24bit version, it's more apparent in the vocals, strings, and woodwind top end.

Now for the question, at long last, am I really comparing 16bit(44.1k), to 24 bit(44.1k), or was HDCD some halfway house, I can't see how even with the most elaborate compression algorithm that a CD can hold enough info for true 24bit.

Now to track down the others...:rolleyes:

[WAD62]

I think I've found the answer;

From Goodwins High End;

"HDCD-encoded CDs can sound better because they are encoded with 20 bits of real musical information, as compared with 16 bits for all other CDs. HDCD overcomes the limitation of the 16-bit CD format by using a sophisticated system to encode the additional 4 bits onto the CD while remaining completely compatible with the existing CD format. HDCD provides more dynamic range, a more focused 3-D soundstage, and noticeably more natural vocal and musical timbre. With HDCD, you get more of the body, depth, and emotion of the original performance—rather than what is more typical which is a flatter, more "digital" imitation"

So they are a half way house, with 20 bits, not quite sure I agree with all of the above however. Still I only have a sample set of 2 (found Flaming lips - 'The Soft Bulletin' also) so I can't really argue.

[Rare Bird]

HDCD was good it's a real shame it got killed off..The Musical Fidelity 'X-DAC', Cambridge Audio 'Isomagic:S700', Rotel 'RCD971', 'RCD 1072' etc etc all had HDCD

[WAD62]

Have you ever had the chance to compare HDCD(20bit) with full 24bit?

[Rare Bird]

Have you ever had the chance to compare HDCD(20bit) with full 24bit?

Yes i think the standard HDCD sound more nice imho.Windows media Player with play HDCD in 24 Bit if you have a 24 bit sound card installed.Try it you will see the logo

[Peter Galbavy]

There is a tick box in the dbPoweramp settings for the HDCD decoder to add 6dB to the samples - apparently by default HDCD is decoded into the lower 20 bits, not the full 24, as it's only 4 bits extra in reality...

PS You can just reconvert the FLAC almost in-place with dbPoweramp, no need to rerip. Just use the batch converter to a temp directory. I haven't been bored enough yet, but in theory you could go through your whole FLAC collection with the HDCD plugin and it would only change the ones it detects.

PPS You need the latest HDCD plugin (which may still be beta and includes the above +6dB gain tick box) as the old version misses some encodings - such as one of Barb Jungr's albums - I reported this in their forum.

[WAD62]

I just wrote a large reply...and have managed to loose it into the ether.

That's how i do it, using the converter

I won't be reprocessing everything as I know i only have a couple (out of 2.5k), and it's nice to be able to have the 2 versions side by side. It would take too long, and I still wouldn't be aware which ones were the HD's without inspecting the tags of a file from each cd.

I had a 15dB variation between the 16bit and the 24bit for spiritualized, so using ReplayGain is better than just adding an arbitrary + 6 via dBpoweramp.

P.S. Winamp has a new feature called ReplayGain pre-amp which is very useful if you use ReplayGain

P.P.S. The 'Flaming lips' one is a swiz, the KBPS on winamp is only 2 more than the original, I've just put the CD in the transport downstairs and the HDCD light comes on, however this CD was a computer copy (Oops!). Another thing is that there was only a 3dB difference between the 16 and 24 bit versions.

Whereas the spiritualized 24bit version has a 50% increase in KBPS (it is the original CD)

[Alex_UK]

I just wrote a large reply...and have managed to loose it into the ether.

Excuse a bit of thread drift - I've done this many times myself, somehow hit the backspace key + shift(?) and end up going to previous page, go forward again and all is lost :steam: - but I've found that if you either start a Quick Reply and Preview Post if you make a mistake the typing seems to be retained when you then hit the Forward button - same as if you use "Go Advanced" from the off when replying, I think. May or may not help for the future!

As you were, move along, nothing to see here... :)

[WAD62]

Cheers Alex,

Normally I'm sensible enough to write it in text pad first and then cut and paste, but I was too busy defending my chicken sandwich from the cat, still the sandwich was nice...or what was left of it.

[WAD62]

Right I through scanning and converting what I have into HDCD FLAC with the following results;

KBPS from winamp;

Spiritualized- 'Let it com down' 50% increase in bit rate (to about 1400KBPS)
Neil Young- 'Mirrorball' 12% increase in bit rate (to about 1000KBPS)
Beck- 'Mutations, Sea Change, Midnight Vultures', all 2 additional k bits per second (bugger all) (to about 889 from 887KBPS)
The Flaming Lips- The Soft Bulletin, the same as Beck bugger all again.

Ducking record industry, the only one that made any difference is the Spiritualized HDCD, but that requires a 15dB bump in replay gain, I suppose it must be as far as one can go with HDCD

As for Neil Young, I can barely tell the difference.

And the others are obviously 16bit masquerading as HDCD, they have enough additional data to make your HDCD LED light up, but that's it. Oh and they're 3dB quieter, so they're probably worse than the 16bits due to signal to noise!!!

Selling standard definition as HDCD, what a bunch of bunts.

I won't be bothering with HDCD again

[Reid Malenfant]

Will, just out of interest have you tried playing the HDCDs in your DVD or whatever drive you are using on your PC without ripping them to FLAC files?

Whenever i play a CD like this via Winamp it always come up with 14xx Kbps. I know i have at least one so called HDCD here so i might try this myself just to see what happens ;)

[WAD62]

As you said Mark they all come up 1411KBPS...

The HDCD's are no different, probably Winamp doesn't recognise the format

All of the albums converted to 24bit, but the file size increase bares a direct correlation to the increase in bit rate, i.e the Spiritualized ones are about 60% larger than the 16 bit equivalents, Neil Young abou 12%, the others are about 3%.

I've a feeling that the others are just 16 bits masquerading as HDCD, and that the FLAC compression is chucking the padded blanks away. But I don't know enough about the compression technique used.

Given that the resultant loss of volume is inversely proportional to the increase in sample rate, I think that it is reaffirming my suspicions that a lot of these HDCDs are trumped up beyond belief!!!!

Time for early doors, talk to you later :cool:

[WAD62]

After some research...

Winamp KBPS for FLAC; Although FLAC is a variable bit rate compression, winamp simply takes the number bits in the file an divides it by the duration, therefore what you see is an average figure for each track, hence variation between tracks within the same album.

FLAC compression; Simply encodes the information available about the wave form into a different, more compact format. Therefore the difference between the KBPS figure for the original 16bit, and the 24bit does represent the additional data available from HDCD, which in some cases is negligable.:rolleyes:

[Chippy_boy]

I haven't read the whole thread (just stumbled across this whilst googling something else).

Just to say that I have all me CD's ripped in Apple lossless format. All of the HDCD encoded ones play through my HDCD dac just as if the data was coming off the disk. i.e. the HDCD symbol lights up and you can hear the difference.

I didn't have to do anything special to make this work. In fact orinally the files were ripped into lossless WMA's using Windows Media Player and the HDCD thing worked with those files too. I later switched to apple format and used dbpoweramp to convert lossless wma to lossless apple and the HDCD encoding has been preserved (as I would expect it to, given it's supposed to be lossless encoding).

Incidentally my DTS encoded CD (I only have one) has been through this process and that plays fine too - i.e. the DTS encoding is also preserved.

[Welder]

I got very pissed off with various music players telling me lies about the bit rate and frequency of my file :steam:
I got this.
http://mediainfo.sourceforge.net/en/Download

It’s a lot quicker than running a file through a frequency analyzer and so far it seems to be telling the truth.

[WAD62]

I haven't read the whole thread (just stumbled across this whilst googling something else).

Just to say that I have all me CD's ripped in Apple lossless format. All of the HDCD encoded ones play through my HDCD dac just as if the data was coming off the disk. i.e. the HDCD symbol lights up and you can hear the difference.

I didn't have to do anything special to make this work. In fact orinally the files were ripped into lossless WMA's using Windows Media Player and the HDCD thing worked with those files too. I later switched to apple format and used dbpoweramp to convert lossless wma to lossless apple and the HDCD encoding has been preserved (as I would expect it to, given it's supposed to be lossless encoding).

Incidentally my DTS encoded CD (I only have one) has been through this process and that plays fine too - i.e. the DTS encoding is also preserved.

Could be the firmware on the DAC itself, mine might be looking for 20 bit HDCD, rather than a 24 bit file input, before it turns the 'red light' on, as it were

[WAD62]

I got very pissed off with various music players telling me lies about the bit rate and frequency of my file :steam:
I got this.
http://mediainfo.sourceforge.net/en/Download

It’s a lot quicker than running a file through a frequency analyzer and so far it seems to be telling the truth.

Now that I am using FFSoX as a FLAC plugin for winamp I'm getting proper 'bit rate' info in the display, the average BPS is a setting on the older FLAC input plugin...:)