Upsampling?

What are the pros and cons? Ive just posted some thoughts on the Meridian G08 in the reviews section so i wont repeat myself here, but how does upsampling work? Ive heard a couple of upsampling players now and whilst there is no disputing the detail they retrieve, both sounded a little too lush if thats the right word?? at the cost of some excitement... Is that a trade off of all upsampling players as a result of the process? Has anyone else noticed this or are my ears playing tricks on me?

 

upsampling is taking cd's data stream of 44,100 samples per second and turning this into a stream of 192,000 samples per second. unfortunately this isn't a simple process. first you are not dealing with twice or 4 times the number of samples you are dealing with 4.3537 times the number of samples i.e. for every 1 origional sample you must generate 4.3537 samples. this process is called sample rate conversion.
next what do you do with these extra samples? well you can either leave them all the same which is simple and will allow you to have a simpler filter (for some reason i cannot fathom but much cleverer people than i say this is so and i for one trust them). a simpler filter means less phase distortion hence a sound closer to the origional.
or you can interpolate basicly this means guessing what the waveform would have done if you were to have recorded at 192khz. for example if the first (origional) sample has a value of 100 and the second sample has a value of 140 then the 3(ish) new samples between these control values may be 110, 120, 130. (Note: this isn;pt an accurate portrayal of the actual sample values as they'd be skewed by the fractional sample rate) this is linear interpolation, there are a multitude of other interpolation schemes from slightly more complex spline interpolation to horribly complex schemes which try to guess at what the music is doing by what goes before and what comes after.
at the end of the day though they are guessing. in fact with the src you are unlikely to get an origional sample value out of a song.
many prefer the sound of traditional oversampling which instead of generating a fractional number of samples generates an integer number i.e. 8 times oversampling will generate 8 intermediate steps between each original sample.
most people seem to agree that the musical results of upsampling are a general increase in detail and spaciality whilst rythmic drive and bouncyness are decreased, this really does seem to go with the territory.
i believe that the only reason upsampling has become so popular of late is that there are now so many cheap dacs that will only accept a 192 khz data stream thanks to the av explosion that companies are slashing costs by using them.
i use a 4x oversampling bitstream / multibit hybrid dac cd player and love it to bits. low tech it may be but it sounds great to me.
cheers


julian

 

. IMHO only direct multipules of red book sound 'interesting' & engauging
2. virtualy (not all) all of the upsampling all in one cdp's sound well 'Bland', detailed and open big stage, etc
3. Using an 'off board upsampler' between a transport & dac for me yields better results (says he who just gone one box at home )
using either 96/192khz the dac has to entwine some form of dsp algorythym to interpolate the 'missing points of the curve', it's a good guess, but guess all the same., me I'm happy with loss leading bit rate Wm

 

I have to wonder if there are any subtle artefacts arising from the conversion from 24 or 32 bit, 48KHz/96KHz in the studio, to 16 bit/44.1KHz for cd stamping. Probably not on the clock speed, but perhaps on the dynamic range?

 

Well the Meridian G08 upsamples by a factor of 4. Does it sound "interesting & engauging"?

 

Hey Hawk,

Your ears are not playing tricks on you. Upsampling is nothing more than a marketing man's gimmick designed to sell more players. People like new things especially if that thing is being marketed as being better than the older versions. That's what hifi magazines are there for. Yet there are not many upsampling players that I've heard that play 'music', meaning that they don't get my foot tapping. The older players or players sans upsampling seem to have that ability to get to the heart of the music in a way that these new upsampling kids on the block don't. If the music is what you are after, then look past what's written on the box or in the brochures. Oh and in the meantime,....................



Enjoy the music,

Lawrie.

 

Chris, I may be wrong but I thought it was 192khz, the answer is not by a very long way, and I'm in agreement with merlin (again ) the G07 is way more enjoyable, if not as open and detailed. T.

 

There is a datasheet downloadable from the Meridian website in which you will find the following:

 

Chris, It's still yawn mode 5 captain, maybe the algorythym they use is 'plink enabled' Me I prefer 88.2, if you can use upsampling, the higher rates (save the msb's 3 times u/s) just flesh out the sound, ideal for nora & co.
I feel you shoud have one of home demo, those castle's would love the chance to chew into wasp with it

 

But Julian, what about the systemic anomoly, or Zion and what happens to "The One" .

 

:lol: Yes, some of those WASP tracks are not too easy on the ear are they. My favourite track on First Blood Last Cuts is also the least ear friendly The Arcam does quite a good balance between nice and nasty on that track. When I bought the Alpha 9, I thought "800 quid for a CD player, I must be crazy", but as time goes on and it continues to defeat all comers, I just think more and more that I got a huge bargain.

 

Voodoo, was it really necessary to quote Julian's ramblings in all of their considerable entirety, just to say that

Having said that, Julian's observation about the proliferation of 192 kHz DAC chips is a good one.

Meridian's datasheet for the G07 makes considerable mention of the fact that the player has 192 kHz capable DACs as if this alone is some guarantee of superior quality but also goes on to state clearly that it runs at 44.1 kHz, thus rendering the 192 kHz capability entirely academic

 

I use a Monarchy Audio DIP 48/96 upsampler in between my transport (modded Teac T1) and Chord DAC64.

It upsamples to either 48 or 96kHz and 24bits and I'm using it at 96kHz. The very same box has graced the system of the great wadia-miester himself

TBH the difference it makes is subtle. Most obvious difference with the DAC64 is that the 4 second RAM buffer delay becomes about 2 seconds (96kHz is just over twice the amount of data per second as 44.1). Soundwise it does give it a bit more of the "round earth" attributes (air, space and smoothness) but all the musicality and timing is left intact :MILD:

Michael.

 

Ok, I use a 'Minor deviated' P1-a, which I've changed the output top sample rate, from 96<>88.2, now it's more than subtle in just about most dacs we've tried it with, even the dac 64 aremember most of them have a reclocking facility as well and a bit rate increase from 16 to 24.
Interestingly the 48khz, is a bloody good trade off , it's not a direct multiple, but it is an old studio standard, it keeps most of the life and drive, whilst cleaning up the top a fair way too. Wm

 

Nice general explination Julian.

This may be somthing obvious. But why do the upsample to 192KHz? What decides this number? Why not a multiple of 44.1k?

 

Mo,

This is what the Simaudio website says about upsampling. I think it is an excellent summing up of the whole issue, and mostly devoid of marketing speak.

 

Nice Robbo

FWIW, upsampling or SRC's seem to IMO give a different presentation which may or may not appeal. All the ones I have heard trade increased smoothness and spaciality for rythmically challenged bass. The only ones that have really impressed are the true interpolators, such as the dCS solution.

BTW Neil, the clever thing with the Eclipse is that you can put an Upsampler into the digital loop on the back, thereby giving you the option of using it on some discs and not on others Nice!

 

Having lived with "the original upsampler" in my system for a quite some time now, I'd say I'd not be without upsampling, but now I suspect I could live without it after recently hearing an oversampling playback system which had been brought up to date with some modern techniques to make sure that the signal purity from disc to DAC and through the analogue stages was being subject to the least corruption...

I prefer to use to use exact multiples of 44.1 too, with 176.4 (@ 24 bit) being my prefered choice. So in this case, it's probably true to say that this is nothing more than oversampling with the additional 8 bits of resolution tacked on via simple bit manipulation.

The upsampled version offers a smoother and more refined and more natural top-end. The claim is that upsampling is able to recover information lost during the down conversion from studio master (16bit/48Khz or higher) to 16/44.1Khz for CD.

Well, I have another theory, it's second guessing and partially recovering and compensating for some of the information lost during CD reading to DAC transceiving process. At least that's what I reckon is happening in the case of a dCS system, synergistically compensating for the jitter and noise from the power supplies. This approach (the upsampling approach) to DA conversion seems to work for other companies with their me too products, but from what I've heard 16bit/44.1Khz with 4 or 8 times oversampling should be able to produce fine results too its just the "margin of error" is much narrower than say with a 24/176.4 signal so much more care needs to be taken for the original signal read from the disc not to be corrupted further downstream.