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HUG - here for all audio enthusiasts

Since its inception ten years ago, the Harbeth User Group's ambition has been to create a lasting knowledge archive. Knowledge is based on facts and observations. Knowledge is timeless. Knowledge is human independent and replicatable. However, we live in new world where thanks to social media, 'facts' have become flexible and personal. HUG operates in that real world.

HUG has two approaches to contributor's Posts. If you have, like us, a scientific mind and are curious about how the ear works, how it can lead us to make the right - and wrong - decisions, and about the technical ins and outs of audio equipment, how it's designed and what choices the designer makes, then the factual area of HUG is for you. The objective methods of comparing audio equipment under controlled conditions has been thoroughly examined here on HUG and elsewhere and can be easily understood and tried with negligible technical knowledge.

Alternatively, if you just like chatting about audio and subjectivity rules for you, then the Subjective Soundings sub-forum is you. If upon examination we think that Posts are better suited to one sub-forum than than the other, they will be redirected during Moderation, which is applied throughout the site.

Questions and Posts about, for example, 'does amplifier A sounds better than amplifier B' or 'which speaker stands or cables are best' are suitable for the Subjective Soundings area.

The Moderators' decision is final in all matters regarding what appears here. That said, very few Posts are rejected. HUG Moderation individually spell and layout checks Posts for clarity but due to the workload, Posts in the Subjective Soundings area, from Oct. 2016 will not be. We regret that but we are unable to accept Posts that present what we consider to be free advertising for products that Harbeth does not make.

That's it! Enjoy!

{Updated Nov. 2016A}
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The truth about high-resolution audio compared with std. CD 44k?

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  • #16
    Comparisons - game rules

    Originally posted by RobHolt View Post
    You also need to consider that the true 24/96 file is likely to have considerable content above 20kHz. Anyone with a file editor can load them up and take a peek. So a great idea so long as there is some basic blind test housekeeping
    Already considered...read message #12 in this thread!

    Ultimately, there is nothing we can do to stop people cheating by examining the audio bandwidth within the test files and claiming that "file X definitely sounds worse than file Y". But remember, it's only a game!

    Comment


    • #17
      Cables - if I can't hear a difference ....

      The last week has been spent in getting digital wireless sound into my reasonably hi fi systems - which are:

      1. Marantz SACD Pearl,Quad 99/909,Harbeth Compact 7 - main system
      2. Denon M38,Spendor S3/5 se - bedroom

      For domestic reasons the latter sits on a long wood desk in the bedroom next to my mac, not the best place for the speakers, but it works quite well for all that, with some vibrapods below the speakers, which are also placed close to the front edge of the desk.

      What has been interesting is that my ears can't hear any difference in sound quality, regardless of what I do at the source/cables, as long as that source is free from gross distortion like hum or static.

      A list of sources/cables tried, in getting to a stable wifi signal feed, including those tried for comparison reasons.

      1. Itunes streaming to Airport Express, connected to the amps via analog wire, and also via optical Toslink
      2. Itunes connected via computer headphone socket to aux in of the amp by analog wire.
      3. Ipod touch streaming via dock connector to a made for ipod USB socket on the amp.
      4. Itunes/mac connected by USB wire to a USB for computer socket on the Marantz.
      5. SACD on Marantz.
      6. LPs on Rega P5.
      7. CDs on Marantz.

      It seems that none of these influence the sound to a degree I can hear in my home. And I have now realised that what I do not hear for myself, isn't worth the trouble or the expense. Of course, the sound is hugely different for the same source in the main living room, and in the bedroom - no surprise there, different speakers, different placement, different room acoustics.

      Comment


      • #18
        Cables only need to met basic criteria ... speakers/rooms vastly more important

        I'm not surpirsed. I think you've nailed it on the head. Cables need to be decent not exotic / expensive (i.e., they need to be undamaged, of appropriate gauge, and designed satisfactorily to get their jobs done).

        Speaker placement and room acoustics are vastly more important IMO and experience.

        Comment


        • #19
          External DACs etc. - another inaudible improvement?

          Originally posted by QChicago View Post
          I'm not surpirsed. I think you've nailed it on the head. Cables need to be decent not exotic / expensive (i.e., they need to be undamaged, of appropriate gauge, and designed satisfactorily to get their jobs done).

          Speaker placement and room acoustics are vastly more important IMO and experience.
          And it isn't just cables. To my ears ( and to the benefit of my wallet!), I also now find that even external DACs are of no audible value. One of things I needed to do in my systems was to connect the mac to the Denon. I was busy researching - which USB DAC is best etc etc - when I thought I should first just run a 8 GBP analog wire from the mac's headphone socket to the RCA aux inputs on the Denon amp. With the mac not injecting any static or hum into the signal, I find that to my ears, it sounds just as good as a CD played in the Denon. There is a reduced volume of sound, I suspect that the current from the mac out is a little lower than usual, but the denon amp has enough head room for my needs in the room to take care of that. It is once that is done that I do not realise the difference between the two sources of course. Another feature of this connection is that the volume can be controlled at the mac as well, though this has its downsides as well.

          I believe that there are products in the market that are sold for improving this mac to amp connection, for prices ranging from 200 GBP to 10000 GBP. Exotic cables apart! I could never afford the 10000 GBP stuff, but before I became a member , and read about this subject in some detail here, I would have put down up to 400-500 GBP for this, including for the two different kinds of cables needed...so it is good to not have golden ears?!!:-)

          I also realise that there may some computers that will inject electrical noise into the signal from the headphone output socket, but these would be the exception I should think. After all, if they did that, it would be heard on headphones as well, rendering that socket pretty much useless.

          Comment


          • #20
            The mechanics of the CD - an overview and data reduction sonics

            Last evening I read an interesting passage on the operation of a CD transport. I am reading Robert Harley's "The Complete Guide to High End Audio" concurrent with "Principles of Digital Audio", Ken Pohlman's definitive text on the subject. My purpose in doing this is to gain a better fundamental understanding of digital audio playback. The fact that music's passion, drive, perspective, and expression can be captured in a stream of one's and zero's, I find absolutely fascinating.

            Prior to this study, I thought that the DAC section in a CD player was the real workhorse; responsible for the majority of processing. It turns out that this is not the case at all. The transport does a lot more than just shine a laser beam on a spinning disc! First of all, the data contained on a CD is not in the familiar SPDIF format. It is stored in what's called EFM or "Eight to Fourteen Modulation". Here, a 8 bit blocks are assigned 14 bit words along with merging bits which are responsible for the data stream. This stream contains not only the audio data, but also the clock signal, table of contents, and error correction data. Pits and Lands are embedded in the optical disc. Both of these result in a binary zero, while the transition from pit to land (or vice versa) correlates to a binary one. A device called an optical decoder divides the audio info, from the subcode and reads and interprets these bits.

            Another assumption that I would have made prior to this reading was that, much like a turntable, the data was read at the exact instant it was converted. This is not so, a certain amount of buffering has to be implemented so that error correction can work properly. This is not to suggest that disc rotation is not precisely controlled; the transport's servo allows for very high degrees of precision. The optical signal coming off the disc is very analog in nature. After all the information is extracted, de-interleaved, and decoded; the end result is the familiar SPDIF bitstream and a clock signal.

            Due to the great complexity of a CD transport, I am convinced that they would account for many of the audible differences heard between various CD players. Another interesting conclusion that is supported by Mr. Harley is that bypassing a transport altogether, and having a computer read the SPDIF data, can result in a more accurate analog output. This is a big advantage music servers have over disc players.

            Since this thread is concerned with digital playback and differences among formats, I thought I would post here. The first 16 entries of the thread seemed to be leading up to an objective comparison of audio files. Then, we got back to the ongoing cable debate. It appears that some such test were already performed with less than definitive results. Even if the testing were to proceed with the most stringent possible regulation, I am doubtful that any objective conclusion would be reached. In a very general sense, it makes sense that more information would translate to better sound quality.

            Lossy compression algorithms have shown that certain information is more musically relevant. A 128Kbs Mp3 stream has less than 1/10th the bit-rate of Redbook CD, yet it does come fairly close to representing the original. Does it sound 10 times worse than Redbook? Would a 256Kbs stream sound twice as good? Does a 24/176 file, recorded at this sample and bit rate, sound 6 times better than CD? Well, I think we've crossed over from an objective to a subjective response with this. I also think there is something very similar to Economic's Law of Diminishing Returns at work. For example, I enjoy listening to Linn Radio which is a 320Kbs stream. This is roughly a quarter of the data rate for CD, but it is considered "Hi-Res" by streaming standards. For the most part, I don't notice anything lacking in the sound. On the rare occasion that they play something that I own, I will listen to it and then play back my file for comparison. This is not a "blind" test and it only accounts for 2/3 of the ABX process. Lets just say that I have to listen very hard for differences. If they exist at all, its not something that I would be willing to bet on being able to detect. On the other hand, does this mean that I should go ahead and compress my entire Library to save on the space occupied by the bits that I just admitted were of little significance?

            Well, maybe, but I'm not going to be doing it, and I wouldn't even if storage were at a premium.

            Comment


            • #21
              The CD system - the engineering reality

              Originally posted by Diminish View Post
              Last evening I read an interesting passage on the operation of a CD transport... Due to the great complexity of a CD transport, I am convinced that they would account for many of the audible differences heard between various CD players...
              Er, no! Have you allowed your preconviction that 'CD players sound different' combined with your abandoned belief that 'DACs sound different' to grasp for a second belief that 'the all important element is the CD mechanism' (I summarise).

              There may well be sonic differences between CD players - I'm not listening for them but I don't doubt that something is audible - but you are barking up the wrong tree if you think the CD mechanism is complex and hence, likely to be the source of any differences. The miracle of the CD concept (as I've discussed long ago) is not its complexity but its extreme electro-mechanical simplicity. I repeat - the Sony/Philips designers intentionally, deliberately and wholeheartedly approached the design of the discs and the players with cost minimisation (aka engineering simplicity) at the very top of the design specification. And were they proved right: absolutely. It was a wonderful collaborative effort between European and Japanese engineers who shared different cultural approaches to engineering perfection, but found a solid common ground.

              The reason is this: driven (rightly) in the early 1980s by marketing predictions of the likely consumer uptake of audio CDs (billions of discs, tens or hundreds of millions of CD player mechanisms), combined with the persistent and costly returns of mis-pressed LP records by the public, the engineers wanted a completely foolproof 'sell and forget' system. Discs that were (are) cheap to duplicate, indestructible, almost totally immune to even severe scratching and with player mechanisms that would cope with anything thrown at them. And that translated in the engineering design to the CD system's ability to cope with a huge spread of manufacturing tolerances in the discs and mechanism plus likely consumer/environmental degradation (another set of wide tolerances). So they anticipated every imaginable scenario of player and disc edge-of-tolerance: just a little bit too fast or too slow, a fresh laser or a weak one after years of use, dust on the laser, rotational bearing wear leading to non-concentric rotation, bearing oil/grease becoming sticky, laser misalignment laterally and vertically, scratches along and across the disc, disc data pits with fuzzy not sharp edges, flaking reflective CD top layer, likely power supply variation country to country, hour to hour etc. etc. etc.. In microcosm, they 'put a man on the moon and brought him back'.

              And what did they conclude? They appreciated that the entire CD player/disc system had to have built-in significant error correction and feedback systems, mechanically and electrically. And these systems themselves had to be robust and reliable, fast acting, completely transparent to the user, automatic, and that the user could not even if he wanted to, 'go manual' and bypass layers upon layers of complex interlinked self-regulating feedback control systems. And that was a genius decision. There could be no tweaking of the transport, no re-writing of the control code, no user controls other than basic play/stop/search and no possibility at all to reinterpret, reinvent or improve upon the transport system devised by the collective genius of the worlds best consumer electronics working across two continents. And that's how it stands today.

              And the consequence of superb engineering foresight was that both the discs themselves and the transport mechanisms could be punched out in sweatshop conditions without the need for a super-clean environment, using simple machinery in the hundreds of millions. No need to tweak and adjust every mechanism. Just bash them out and flog them in vast quantities. And that ensured (as Sony/Philips anticipated) that the cost of producing the mechanism would fall to little more than the cost of producing the disc, wholly unlike the LP record and its player mechanism.

              Attached is a scan from a current (and rather pricey) trade catalogue listing CD and DVD players for the PC. They sell the mechanism in a tin case to suit a PC, in a nice cardboard box with instructions, screws, audio cable etc.. Item B, cost GBP 12.95 will have a mechanism that is functionally identical to what you'll find in an audio CD system (plus lots of additional features incl. Lightscribe, ability to read and write up to 48x - CD audio is only 1 x). Item D can read BlueRay which is a far, far more complex disk to read and interpret than CD audio. It's cost, GBP 42.95. From this I suppose we can assume that the cost of the mechanism itself, made in China, can be no more than a few dollars.

              And as for 'jitter'; the implications of that certain inevitability was fully considered by the Sony/Philips designers who built-in perfectly adequate and completely robust correction systems to guarantee that it just would not be an issue at all for the consumer.

              >
              Attached Files
              Alan A. Shaw
              Designer, owner
              Harbeth Audio UK

              Comment


              • #22
                Watkinson's 'Law'...

                ...states that if the data is recoverable, the sound of a digital audio system is entirely dependent upon the quality of the converter sub-systems at either end of the process.

                This means that nothing happening between the two converters has any bearing at all on the sound quality, provided that the data remains 100% recoverable.

                Discuss....

                Comment


                • #23
                  First generation CD player v. latest ones ....

                  Originally posted by A.S. View Post
                  There could be no tweaking of the transport, no re-writing of the control code, no user controls other than basic play/stop/search and no possibility at all to reinterpret, reinvent or improve upon the collective genius of the worlds best consumer electronics working across two continents. And that's how it stands today.
                  >
                  A question, based on the above.

                  From all one reads, there is a vast difference in the audio quality between the first generation of CD players from a couple of decades ago, and those of today - which themselves are sold at prices ranging from around GBP 50 to GBP 2500 or more.

                  Is there anyone that has done an ABX comparison of the sound from the three types referred to above, played through a set of speakers like Harbeths/others in that category? By three, I mean a first generation CD player and two from different ends of the price ranges of today.

                  I ask the question because I have read so much about how the current generation of CD players, even the budget end, are so very improved from those in the early days of CDs, which sounded sterile, flat, or whatever other audiophile expletives can be used to describe them.

                  Or is this another example of high end audio marketing hype?

                  Comment


                  • #24
                    Marketing hype... essential?

                    Originally posted by Kumar Kane View Post
                    ...Or is this another example of high end audio marketing hype?
                    To be fair ... the present global economic system shows what happens when people stop believing the marketing hype. They don't spend money. What is better? Going along with the BS only half expecting total satisfaction or the economic stagnation of not spending money at all?

                    Comment


                    • #25
                      Don't chase rainbows ...

                      Originally posted by HUG-1 View Post
                      To be fair ... the present global economic system shows what happens when people stop believing the marketing hype. They don't spend money. What is better? Going along with the BS only half expecting total satisfaction or the economic stagnation of not spending money at all?
                      Long term it is certainly better in my opinion to not spend the money chasing rainbows. Yes, there will be a lot of pain while the system self corrects, but given the people v natural resources imbalance, that would the most sustainable way forward for humanity.

                      That said, and human nature being what it is, I don't see that disbelief in marketing hype will last for long...pity.

                      Comment


                      • #26
                        Loss of interest in audio due to the 'nutter' element, not economics

                        Originally posted by HUG-1 View Post
                        ...the present global economic system shows what happens when people stop believing the marketing hype...
                        I hardly think that the present global economic position is down to people no longer buying overpriced CD players! But I do believe that, in the UK at any rate, the overall loss of interest in decent domestic audio is, in significant measure, due to the 'loony toons' approach to marketing. 'Audiophile' has become a byword for a nutter who spends 100 on a cable on which 'normal' people spend 1. Or one who plays vinyl when the world has largely moved to iPods.

                        Those (consumer research people) who advise manufacturers have driven domestic products into ever more stratospheric regions and come up with the hype to promote them. The reality is that there haven't been any truly significant developments, particularly in analogue design, for the last twenty years. There are very few instances of a state of the art analogue product of twenty years ago not remaining entirely satisfactory today.

                        Comment


                        • #27
                          Sound differences

                          Just a very general observation/opinion triggered by this thread.

                          C'mon, just a little more time and at Harbeth's you're gone tell us that all LP cartridges sound the same!
                          And that it doesn't matter at all in whatever turntable and arm and on what surface.
                          Because we do play the same LP grooves > but here we "can explain?" that there's also a lot of mechanics involved

                          Not all sounddifferences can be explained nor ignored just by finding technical explications, as far(little) as we now know!

                          Also the speakerstands, powercables, loudspeakercable and interconnects or combination's should sound all alike according to Harbeth's with very little sounddifferences.

                          40 years ago general opinion was that all amplifiers with (than known specs!!) should sound the same, and......?
                          .....even the amp.housing proved to be of influence on the sound

                          I believe in Harbeth's sound and designs and so do a lot of people....and
                          ....guess what > lot of technics, but "for us" no specs, but finetuned by a trained ear for the right sound and trust in it.

                          No, IMO there are a lot of different sounding electronics, interfaces and combinations and much different pricing.
                          You don't have to steal the bank, but you'll have to find your own Walhalla against your costprice!

                          Comment


                          • #28
                            Ultimate consumption and human nature

                            Originally posted by HUG-1 View Post
                            To be fair ... the present global economic system shows what happens when people stop believing the marketing hype. They don't spend money. ...
                            If only I believed it were actually a matter of choice ...

                            People aren't spending money because they have no money (or much less money) to spend. It's that simple. The reasons why this is so are manifold and complex, but the effect is simple. When your ability to spend is restricted, you tend to focus on what's essential and cut the frills. Not surprising.

                            However, I don't think a change in economic circumstances has changed human nature. If we turn the corner on the current worldwide economic problems, I think things will be the same as they ever where. The fundamental question is whether we are now at a point where it's simply no longer possible to live a life based on unlimited consumption on a planet with limited and finite natural resources.

                            Comment


                            • #29
                              CD transports

                              "Er, no! Have you allowed your preconviction that 'CD players sound different' combined with your abandoned belief that 'DACs sound different' to grasp for a second belief that 'the all important element is the CD mechanism' (I summarise)."

                              Was this intended as a question? I have to continually remind myself that this is the HUG, albeit the "your views, not Harbeth's" section. The notion that CD players sound different is more of an axiom to me than something requiring proof and open to debate. If the above quote was intended as a question, please allow me to point out that I have not abandoned my belief that DAC's sound different. I was re-evaluating my view of the transport's contribution to the audible difference between players. You state that "The miracle of the CD concept (as I've discussed long ago) is not its complexity but its extreme electro-mechanical simplicity." Prior to this reading, I thought that the transport was SPDIF in, SPDIF out; basically just converting optical data to electronic. I was unaware of the EFM code, interveavened data, Reed-Solomon Code, and error correction that takes place prior to the generation of a SPDIF bitstream. I'm not putting it up there with the Human Genome Project, but to a layman such as myself; a CD transport is rather complex. The fact that it is an electro-mechanical process, and not simply electronic, would suggest complexity greater than that of a DAC. There is also an optical component to a transport, and data is subject to more processing in the transport than the DAC. Complexity is defined as "being characterized by a highly involved arrangement of parts, units, ect." I think that a transport meets this qualification. In fact, HUG-1, goes on to discuss the "layers upon layers of complex interlinked self-regulating feedback control systems" incorporated in a CD transport.

                              Just because something is complex does not mean it is inaccurate, in fact, transports are designed for accuracy, precision, predictability, and replicability. Paradoxically, added complexity also invites a greater potential for error. This is what I was focusing on when I asserted that transports could have a greater impact on a CD player's sound quality. Bypassing a transport altogether and playing files from a computer's hard drive in their SPDIF format can and does result in improved sound quality. This view is integral to the music server and computer audio industry, and it is one where I'm in very good company. It might also be noteworthy in discussing the drop in sales of CD players.

                              {Moderator's comment: factually, CD transports are elegantly simple devices. Have you looked inside one? You just can't get simpler than a motor, a spindle and a laser arm and a little processing logic. Would you like us to disassemble one to show you?}

                              Comment


                              • #30
                                Inside the CD transport

                                Originally posted by A.S. View Post
                                ...The miracle of the CD concept (as I've discussed long ago) is not its complexity but its extreme electro-mechanical simplicity...
                                Here are some pictures of just how few parts are needed to make a CD mechanism. The three key elements are the laser arm, the motor and the means of holding the disk and/or ejecting it.

                                Here is the whole shooting match. Move the mouse on this image of the laser arm to see how simple it is. The data streams right out of the laser pickup through what is probably these days just one IC. A simpler, more ecologically friendly, lower cost device for spinning a disc you cannot imagine. It is the last word in engineering efficiency, and low, low cost. Many images of the parts needed to assemble a CD/DVD transport here. Seems that the laser head is under USD1 as I commented previously. So, cut down to the very basics (small circuit board not shown) is the Philips mechanism on the attached picture. Although it doesn't have a drawer, if you were to place a CD on the spindle perhaps weighed down by a puck (as they do on fancy audiophile CD players) you will be able to play the disk and hear music. It just doesn't get simpler or more elegant than that.

                                Ironically, there are more parts and greater precision of assembly required (and more cost) to make a cassette mechanism than a CD transport*. So there is definitely no correlation between engineering complexity and sound quality - perhaps the opposite is true.

                                >

                                *One reason: there are many feedback control systems in a CD transport to take care of wide tolerances. The cassette transport does not have such digital feedback and relies heavily on mechanical precision - which cannot be maintained over a long period due to wear and dirt etc..
                                Attached Files
                                Alan A. Shaw
                                Designer, owner
                                Harbeth Audio UK

                                Comment

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