Source comparison - listening test: analogue outputs from different CD players

[thurston]

...did not really understand everything in the previous posts yet but I´ll keep trying.

One thing I did however is to buy an (old, un-remastered) version of Stelly Dan´s "Aja" via eBay. I have the remastered version here as well (borrowed from a friend) and liked the sound, allthough I can honestly say that it felt somewhat loud and too overwhelming sometimes.

(other side-effect: because so many people think of cd´s as something of the past, nearly like vinyl, there are lots of bargains to be made second-hand. And usually the unremastered versions are cheaper. Had to buy Led Zeppelins IV as well looking forward to Sandy Denny on "Battle Of Evermore"...ahh!)

[thurston]

Interesting homepage: http://www.dr.loudness-war.info/

Lots of cd´s were tested to quantify their loudness/compression. If they are right my fears referring "Aja" are not justified.

Extremely difficult to trust your own ears, I am nearly dumb it seems!!

[A.S.]

Firstly, many thanks Alan for posts 30 and 31 - I have come back to them several times over the past couple of days and will continue to do so as my understanding of their implications increases at each reading.

Secondly - some time ago (around 18 months or so) discussions of mp3 encoding had progressed quite a long way on HUG and I don't intend to sidetrack this thread back into that area, however one issue that really stuck for me was that the encoding does not simply remove information it also creates noise and that 'masking' is the rug under which this noise is swept. Reading further into this, the issue that I arrived at was 'quantization' ...

Thanks for feedback.

Actually, a few years ago when MP3 was a hot topic, I gave a short presentation to a pro audio conference about this very issue of quantisation, and the implications of multiple encode-decode-re-encode. What I did - and I think I'll recreate it again - was to use the multi-track audio editor to place side by side (in a vertical stack actually) the recording at each step in the encode-decode cycle. You could see significant changes in the waveform from generation to generation, so that after about three or four cycles it was really markedly different in appearance.

I didn't have the technology then to give a demonstration of how the sound changed by switching quickly from one generation to another, but here on HUG we can do that now. I'll add it to the growing heap of things to present: remind me in a month or so please.

[A.S.]

I hold Steely Dan as my favourite rock band and it's interesting to read now, decades later, how hard they worked to achieve technical and sonic perfection. I had no idea in the 70s that their attraction to me was the special combination of the great music plus great sound: I just liked what I heard.

Seems though that it wasn't all plain sailing .... read here about noise reduction problems from the era of analogue tape. Yo analogue! No wonder they were amongst the first to go digital.

Also read the reality of squeezing playable music onto a vinyl record.

[denjo]

Hi Alan

This is a very interesting thread! Are you then saying that ALL DACs playing through the same amplifier and speakers would sound the same (identical)?

Would speakers that use the same drivers as Harbeths all sound the same, whatever the enclosure, wires, connectors, crossover? Surely not right? That would be diminishing the labourious work that you have put in to design the crossover, the cabinets, etc? Equally, why should ALL DACs sound the same since each manufacturer would use a standard DAC chip and then expend time, money, effort and material tweaking with opamps, etc, to make it sound like what they think sounds the best. Am I correct?

Best Regards
Dennis

[A.S.]

No it would be ridiculous to say that all DACS, amps, cables or whatever was of identical performance. The point is how big are those performance differences if they do exist And are they repeatable?

Would speakers that use the same drivers as Harbeths all sound the same, whatever the enclosure, wires, connectors, crossover? Surely not right? ...

Can't answer that precisely because we make all our own bass/midrange drivers at Harbeth UK. So no other brand has our technology. But if they did, and copied all the parts you mentioned, why wouldn't the sound the same? There is no magic ingredient that we build-in, much though you may like to believe that! The designs all obeys the universal laws of physics

How do you tweak op amps? They are, by definition, dozens of transistors in one, neat, sealed, cheap package. If you want to tweak, you have to build the equivalent circuitry with individual transistors, then you have complete flexibility (and huge complexity/reliability/cost/pcb issues.)

[Stephen PG]

No it would be ridiculous to say that all DACS, amps, cables or whatever was of identical performance. The point is how big are those performance differences if they do exist And are they repeatable?

Only one person here has attempted this so far...

Speaks volumes...

[thurston]

...I will never really understand how much people insist on huge (audible) differences between amps, cd-players and dacs that are almost unmeasureably different.

You have to bear in mind that you try to hear ultra tiny differences by using a comparably bad reproducer (the speaker) and an equally bad measuring device (the ear).
The differences may be measureable but after processing the above mentioned stages they are trashed.
All the more when the usual listening room further trashes the frequency curves.

[Stephen PG]

...I will never really understand how much people insist on huge (audible) differences between amps, cd-players and dacs that are almost unmeasureably different.

thurston,

Blatant self-aggrandisement, plain and simple... or 'see how good my hearing is, if you can't hear this, you must be deaf...'

Read between the lines of almost all posts in the subjective fora, and this is what you'll find.

[thurston]

ok, in fact it is really easy to understand!

I have to confess that it took me quite some time to believe my own ears when I did NOT hear differences. When I think about how long it took to listen to a Mission Cyrus, Thorens and Aura-CD-Player 15 years ago untill finally buying the Mission.

And being completely true to myself: I liked the toploader-mechanism...

Just fancy stuff.

[Stephen PG]

Can we please have access to the two files so that we can here at HUG HQ place them on the page in the usual way?

I made a right pigs ear of that, didn't I! Sorry... here they are

Loading the player ...

Clip L

Loading the player ...

Clip M

[A.S.]

Seems to me that L sounds markedly louder than M. Are these supposed to be at the same replay level?

Can you just remind us please what these two clip are allowing us to compare please?

[STHLS5]

L is louder and both sound identical except when you push the volume up then you find M feels a little gentle to the ears on longer (like an hour) listening. Interestingly, I see the difference better with IPad and my laptop then the desktop. For the Ipad and desktop I used Sennheiser earphones.

ST

[Stephen PG]

Seems to me that L sounds markedly louder than M. Are these supposed to be at the same replay level?

Can you just remind us please what these two clip are allowing us to compare please?

Ok.

One is the rip from the CD using EAC.

One is recorded from the output of a CD player.

One has been through the A to D converter of my PC.

One hasn't.

One to rule them all...


Ok, that last one was a joke!

[A.S.]

Can you confirm if you have applied any signal processing at all? I mean, did you open any of the files in an audio editor and perform any tone/loudness/eq to L or M?

I much appreciate your effort to give us these clips. However, my long experience of A-B comparisons cautions me that we must only change one variable at a time. For example, we could change loudness in A but not in B. We could change the tone of A (using equalisers) but not alter B. But if we simultaneously changed the loudness and/or the tone of one but not the other, we would have introduced two variables. It would be impossible to reliably mentally appraise each of the two variables in isolation - the ear would fuse their effect together. We could easily jump to the wrong conclusion.

A practical example: if you simultaneously swapped your amplifier and your speakers, how could you possibly comment authoritatively about the sonic effect of either part in isolation? You couldn't: your experience would be a composite of both. Would you believe it: I have observed visitors to a hi-fi show enter an unfamiliar room, playing unfamiliar music on unfamiliar speakers (that's a minimum of three variables, plus maybe cables, interconnects etc. etc.) and, sighting a certain brand of amplifier, announce to the room that the reason the demo sounds so good/bad is entirely because of the amp. That makes no sense at all.

[Stephen PG]

Can you confirm if you have applied any signal processing at all? I mean, did you open any of the files in an audio editor and perform any tone/loudness/eq to L or M?

None at all.

All I did was play the ripped file in Audacity to set the record level of the one I recorded from the CD player.

I obviously missed by a bit...the dB meter on Audacity could be better.

[A.S.]

None at all. All I did was play the ripped file in Audacity to set the record level of the one I recorded from the CD player.

I obviously missed by a bit...the dB meter on Audacity could be better.

No other changes to the audio files other than the (approximate, by eye) level adjustment? Sure?

[Stephen PG]

No other changes to the audio files other than the (approximate, by eye) level adjustment? Sure?

Yes, I am.

[A.S.]

I'm really surprised. Also the same source disk?

Did you notice that, upon examination of the audio waveforms A and B, there are significant visual differences in dynamic (transient) range? And also a 3dB difference in level.

[STHLS5]

Looks like some posts are missing. I think one is the digital copy of the CD and another one is the analogue sound recorded using his PC. I am surprised that the sound difference is not obvious.

Stephen, what's the answer for your post No 2?

ST