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HDCD old hat?

Minio

Kind of Sort of Not really...
As the years have gone by the once lauded HDCD seems to have got left behind with the steam engines.
It still sounds great to me though, what few copies I have of the format.

I've come to realise how little I know about this technology.

For example, is it a special DAC that is required to reproduce HDCD or the transport?
 
You need a special DAC or can rip the CD to a computer and process the file to 24 bit for any modern DAC
 
As the years have gone by the once lauded HDCD seems to have got left behind with the steam engines.
It still sounds great to me though, what few copies I have of the format.

I've come to realise how little I know about this technology.

For example, is it a special DAC that is required to reproduce HDCD or the transport?

It's a special digital filter ic, which is a component in the DAC circuit of course. I think there were only ever two variants, the PMD100 and PMD200, I'm not too sure how these actually work but they effectively extrapolate a 20bit data stream from a 16bit stream which can then be fed to any 20bit/44.1 or higher DAC chip. Somebody correct me if I'm wrong.

PS, any transport will work. Some computer software (windows media player included) can decode it in software too so your ripped HDCDs should have the extra dynamic range intact, theoretically anyway. And a bit for bit rip should put the HDCD light on on a compatible DAC.
 
That's interesting.

Are there any currently available DACs that include those filters?
 
That's interesting.

Are there any currently available DACs that include those filters?

Just picked up a retro Deltec SX128, which has a HDCD filter, just need some CD's to test it :D I think one of the Musical fidelity 'X' series DACs has one too, they can be had quite cheaply.
 
Microsoft bought the company, so it disappeared from anything that they didn't want to have it. I agree it could work well when the recording staff were bright enough to use it well. There was also Sony superbitmap that did something useful.
 
You can rip HDCD and keep the benefits using dBpoweramp you just have to add the DSP setting.

In my collection HDCD discs are rather rare... 5 out of nearly 1500 pop and folk CDs when I went through the collection recently looking for special formats (SACD, HDCD, DVD, BRA...)

If you have as few (in percentage terms) as I have wouldn't it make more sense just to rip them with the right settings in dBpoweramp?
 
As the years have gone by the once lauded HDCD seems to have got left behind with the steam engines.
It still sounds great to me though, what few copies I have of the format.

I've come to realise how little I know about this technology.

For example, is it a special DAC that is required to reproduce HDCD or the transport?
you might want to look here:

http://www.audiomisc.co.uk/HFN/HDCD/Enigma.html
The author, Jim Lesurf, hangs out around these parts.
 
Plenty of older players about. Naim, of course, still make 2 HDCD-capable players.

I have at least 60 HDCDs (mostly the Warner catalogue, some Capitol etc) which all sound great.
 
It's a special digital filter ic, which is a component in the DAC circuit of course. I think there were only ever two variants, the PMD100 and PMD200, I'm not too sure how these actually work but they effectively extrapolate a 20bit data stream from a 16bit stream which can then be fed to any 20bit/44.1 or higher DAC chip. Somebody correct me if I'm wrong.

So far as we can tell, virtually no HDCDs, and virtually no 'decoders', ever actually used the claimed 'filter options'. All the HDCD rips I've examined lack the flags for them. Someone at Linn records told me they've never used this or seen it done. Others have said much the same.

And in practice unless you apply the HDCD peak compression in a heavy-handed way, you can't expect much more than about 1 bit's worth of 'expansion'. Given how well noise shaping works this isn't worth the effort. So no surprise that HDCD largely died out.

The reality is that a carefully made CD will be as good. The snag being how to compare. Any HDCD that uses more than a tad of peak compression will have its sound degraded by this when played without HDCD processing. So simply playing it on a 'normal' system won't tell you what the sound *would* have been if not peak-compressed for HDCD.
 
Microsoft bought the company, so it disappeared from anything that they didn't want to have it.

They bought PM for the people, not for HDCD. These people were then supposed to develop speaker equalisation methods for building into Windows, to be used to optimise desktop and monitor speaker sound.
 
Every now and then i pop a CD in my Naim CDS3 and a HDCD sign pops up to tell me it is such. Can't say i pay much attention as it doesn't strike me as sounding any different to the majority of my other CDs. Like everything, good and bad recordings in normal CD formats far outweigh any so called 'extra' bits.
 
So far as we can tell, virtually no HDCDs, and virtually no 'decoders', ever actually used the claimed 'filter options'. All the HDCD rips I've examined lack the flags for them. Someone at Linn records told me they've never used this or seen it done. Others have said much the same.

And in practice unless you apply the HDCD peak compression in a heavy-handed way, you can't expect much more than about 1 bit's worth of 'expansion'. Given how well noise shaping works this isn't worth the effort. So no surprise that HDCD largely died out.

The reality is that a carefully made CD will be as good. The snag being how to compare. Any HDCD that uses more than a tad of peak compression will have its sound degraded by this when played without HDCD processing. So simply playing it on a 'normal' system won't tell you what the sound *would* have been if not peak-compressed for HDCD.

No, you wouldn't get filter options on an HDCD machine because they use one of two Pacific Microsonics filter chips.

I have two HDCD machines (linn Genki and Ikemi) and used to have a CD12 too, they sound great but then they still sound great on normal CDs anyway.
 
No, you wouldn't get filter options on an HDCD machine because they use one of two Pacific Microsonics filter chips.

The HDCD standard has provisions for sub-code controlled switching of replay filters, in conjuction with similar dynamic anti-alias filter switching during the production-side downsampling of the 88.2k original signal to the 44.1k of CD.

However, there is so far no evidence at all that any commercial discs actually use this option.


As an aside, I analysed the few HDCD discs that I have, and found that none of them contain actual HDCD processing. All they do is light a LED.
 
The HDCD standard has provisions for sub-code controlled switching of replay filters, in conjuction with similar dynamic anti-alias filter switching during the production-side downsampling of the 88.2k original signal to the 44.1k of CD.

However, there is so far no evidence at all that any commercial discs actually use this option.


As an aside, I analysed the few HDCD discs that I have, and found that none of them contain actual HDCD processing. All they do is light a LED.

So long as the placebo effect works haha. I have found that my HDCD capable machines just sound good with any well produced CD.
 
No, you wouldn't get filter options on an HDCD machine because they use one of two Pacific Microsonics filter chips.


Sorry, looks like my meaning wasn't clear.

The Patents, etc, for HDCD claimed that *it* would cause a choice of filter, controlled by the disc. My point is that no avtual HDCDs I've found actually have the code for this, and others in the biz tell me that - so far as I know - these weren't used on recordings.

i.e. The *discs* don't have any code for this to happen. If someone has a *measured* example where a decoder actually plays a commercial-release disc which does this, please say.

I wasn't talking about the *user* having a choice of filter.
 
As an aside, I analysed the few HDCD discs that I have, and found that none of them contain actual HDCD processing. All they do is light a LED.


FWIW Using the HDCD analysis/decoding software on my website I did find and document examples of how both the peak compression and gain tweaking codes were used to extend the output dynamic range. However the 'improvement' is slight. If anyone is interested the results are got and shown here:

http://www.audiomisc.co.uk/HFN/HDCD/Examined.html

The snag is that to be effective the 'peak compression' process needs to squash the peaks when played without a decoder. Thus spoiling the results and contaminating any attempt to do a comparision.
 
FWIW Using the HDCD analysis/decoding software on my website I did find and document examples of how both the peak compression and gain tweaking codes were used to extend the output dynamic :prange. However the 'improvement' is slight. If anyone is interested the results are got and shown here:

http://www.audiomisc.co.uk/HFN/HDCD/Examined.html

The snag is that to be effective the 'peak compression' process needs to squash the peaks when played without a decoder. Thus spoiling the results and contaminating any attempt to do a comparision.

Cool, I'll look over that a bit later but right now my I'm on the beach in Benidorm and browsing on my phone... yes I'm that sad.:p
 


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