Do you hear a difference?

[mmorrison55]

I have had my lumin mini now for a few months and while I do admit to better SQ now vs when I was doing AirPlay thru my AppleTV, I don’t know that I can say that I hear any difference in SQ of the “cd” vs “his res” streaming sources. I currently have a Quboz hi res subscription and I am currently trying out a trial of Tidal to co pare the two services,  but I can honestly say, I’m not hearing any difference between CD, MQA, or his res FLAC.

It’s highly likely that as I approach 50, my hearing is not what it used to be and I can’t differentiate the higher kHz, or I’m just not “trained” to hear the difference. based on my trials, I guess I can save myself a few $$$ and go with the basic cd quality subscription.

Curious if you guys do hear differences then what are you actually listening for or hearing that is different in the cd vs hi res feed?

[David A]

I have had my lumin mini now for a few months and while I do admit to better SQ now vs when I was doing AirPlay thru my AppleTV, I don’t know that I can say that I hear any difference in SQ of the “cd” vs “his res” streaming sources. I currently have a Quboz hi res subscription and I am currently trying out a trial of Tidal to co pare the two services,  it I can honestly say, I’m not hearing any difference between CD, MQA, or his res FLAC.

It’s highly likely that as I approach 50, my hearing is not what it used to be and I can’t differentiate the higher kHz, or I’m just not “trained” to hear the difference. based on my trials, I guess I can save myself a few $$$ and go with the basic cd quality subscription.

Curious if you guys do hear differences then what are you actually listening for or hearing that is different in the cd vs hi res feed?

Approaching 50? What's your problem? I'm 71, approaching 72, and last time I tried I couldn't hear a 12 kHz test tone.  :-)

Seriously, my high frequency hearing has declined and I'm starting to get a little tinnitus but I can still discern differences between high res music streamed from my server and CD quality music streamed from the server. I don't stream much high res music from Tidal and what they have is MQA which I'm not convinced by. I don't think CD quality 44.1/16 streamed from Tidal sounds quite as good as the same disc streamed from my server and I don't thing 96/24 MQA streamed from Tidal sounds as good as a 96/24 non-MQA high res file of the same disc streamed from my server. Tidal is good but in my experience it doesn't deliver quite the same quality as you will hear from the same music at the same resolution if you're streaming the file from your own server.

OK, to your hearing and listening. We all progressively lose high frequency hearing as we get older and that's a slow, gradual process so we don't notice it as it happens. It only becomes apparent when you do something like listening to test tones. It's like your eyes and ageing. You only tend to notice you need new glasses when your arms get too short. You don't notice it while you can adjust your distance for reading and close work.

We tend to think of 20 kHz as the upper limit of our hearing but 20 kHz is often gone or going for us in our early 20s and our upper limit keeps dropping from there. At 50 most people probably haven't been able to hear 20 kHz for more than 2 decades, possibly even 3 decades. On the other hand the highest fundamental produced by a musical instrument is a bit over 7 kHz and all we have above that are harmonics. It's the harmonics which give instruments and voices their characteristic tone and whatever your current hearing upper limit is, you're still going to be hearing a lot of overtones given that all voices and most notes played by instruments are in the range below 4 kHz and a lot below 1 kHz. The bottom 5 octaves are below 1024 Hz. The top octave above 10 kHz definitely adds something but it adds less than you might think given the amount of stress that tends to get placed on statements that the upper limit of our hearing is 20 kHz. 

If you want to hear differences then listen to things that are familiar to you and don't focus on any one thing like the highs. I tend to listen to how voices sound because we're probably more used to voices than anything else and you can listen to someone you don't know speaking on a phone or TV or some  low quality reproducer and easily pick things like whether or not they have a cold, even when you don't know their voice, simply because we're used to picking unusual colourations in voices. Another thing about listening to the sound generally without focussing an any particular is that it's easy to get fooled by particulars. Hear a specific difference and we immediately start thinking that's better or that's worse but often a judgement that it's worse simply means that it's not what we expected so it disturbs us and if we keep listening and get used to the new way it sounds we can end up thinking that it's actually better, not worse. Unfamiliarity makes it harder to make reliable judgements. I find that just listening to the music for a while, and I mean a whole disc or even for a day or two, and then swapping back to the alternative gives me a better idea. If I find myself relaxing and thinking "this is what it should sound like" after I swap back then I know that there's something I don't like in what I've been listening to and if, instead, I immediately want to swap back to what I was listening to previously then I know that there's something I prefer there, even though I may be hard pressed to identify clearly just what the difference is. Quick A/B testing by swapping between one thing and another is good for picking up some differences but not for picking up every difference.

Another thing to listen for is detail in terms of how distinct different instruments are from each other, how tonally different they sound, and how natural a particular instrument sounds if you're really familiar with the sound of that instrument which probably means it's an instrument you play or hear played live very very frequently. There can be large variations in the character of the sound from one piano to another or one acoustic guitar or bass to another depending on the make and model of the instrument and who's playing it but there are common characteristics to the sound from a given sort of instrument. The more different instruments of the same sort that you've heard live, especially relatively close up in normal sized rooms rather than concert halls, and the more different players you've heard playing them, the easier it becomes to know what to expect from a given instrument generally rather than what to expect from a particular instrument played by a particular person. Voices are a lot easier to judge than instruments in my experience.

And definitely don't worry too much about the highest frequencies. You aren't going to notice much difference there if your hearing is down there. Where you're going to notice differences is in the range you can hear and there's a lot more differences you can notice there than most people think.

So my advice if you want to hear differences is to do some normal A/B testing with quick swaps between alternatives but also to stop listening for differences, just relax and settle into the music while listening to the new alternative and once you're really relaxed and feeling familiar with the sound of that, swap back to the previous option and just see what your gut response is. I can assure you that you certainly are capable of noticing differences but quite often the subtler the difference is, the harder it is to pick if you focus on differences and do quick comparisons. Sometimes  you need to give yourself time to get used to the new then swap back and see how you feel about the original option after you've been away from it for quite a while, and don't be surprised if you find yourself noticing a difference then but not being able to clearly and specifically state just what that difference is. It can end up just boiling down to having a preference for one over the other and not really knowing why.

[Pim]

It’s highly likely that as I approach 50, my hearing is not what it used to be and I can’t differentiate the higher kHz, 

No human being can hear above CD quality's top frequency so don't feel bad about it. Those who hear a difference are hearing a difference in mastering, not 30+ thousand Hertz.

[Jean-Marie]

It’s highly likely that as I approach 50, my hearing is not what it used to be and I can’t differentiate the higher kHz, 

No human being can hear above CD quality's top frequency so don't feel bad about it. Those who hear a difference are hearing a difference in mastering, not 30+ thousand Hertz.

^__ This a thousand times!

Jean-Marie

[David A]

It’s highly likely that as I approach 50, my hearing is not what it used to be and I can’t differentiate the higher kHz, 

No human being can hear above CD quality's top frequency so don't feel bad about it. Those who hear a difference are hearing a difference in mastering, not 30+ thousand Hertz.

Not so fast  :-)

Equipment generates harmonic distortion based on overtones of frequencies in the signal and it also generates intermodulation distortion based on frequencies related to the difference between frequencies contained in the signal. Take a look at the plots of intermodulation distortion occurring for tones of 19 and 20 kHz in John Atkinson's test reports of amps in Stereophile. Most of us here can no longer hear 19 and 20 kHz test tones yet the presence of tones we can no longer hear in a signal is capable of generating effects all the way down to 1 kHz which we most certainly can hear. I have a CD of Meredith Monk, an experimental composer and performer, running her moistened finger around the rim of a wine glass to produce one tone and singing a sound that starts off just below that pitch and increases to just above it and then going back below the pitch again and repeating this process for over a minute. Listen to the track and you hear a difference tone which appears to be located within your ear.

Once we start to consider overtones and difference tones, sounds above the limit of our hearing—whether that be the theoretical 20 kHz limit or our own personal hearing limit—can most certainly produce effects in the audible range. The fact that we may not be able to hear the frequencies in the signal doesn't prevent them from having effects in the audible range so what we can't hear can actually have an audible effect.

You can classify these effects as distortion and they certainly satisfy the strict definition of distortion but not all distortion is unpleasant and some distortions such as the first, second and third overtones actually which are also produced by instruments and voices actually contribute to the richness of musical sounds. Not all distortion is unpleasant.

It's easy to say that we can't hear frequencies above the limit of a CD's top frequency and that's true but that doesn't mean that frequencies above that limit can't have effects in the audible range and influence our perception of the tonal character of music.

The limits of our hearing are determined by listening to pure test tones of a single frequency. Music is made up of multiple simultaneous tones produced by different instruments or voices, or several tones produced at the same time by the one instrument, and even 2 tones produced simultaneously by the same voice in overtone singing, and all of those musical tones have overtones and difference products can occur between all of the frequencies involved. Overtones above the audible range do affect our perception of tonal characteristics off musical sounds.

Tests of our hearing ability done with single tones aren't a reliable guide to what we hear when we're listening to music with multiple simultaneous tones and the upper limit of our hearing as determined by single tone tests doesn't stop higher frequencies in musical sound having effects well within our hearing range.


I agree that the quality of mastering plays a part in what we hear and that  high res recordings are often mastered with greater care and attention which does make a difference but frequencies above the limit of our hearing do have effects which we can hear, even if we can't hear some of the frequencies contributing to those effects.

Things are usually a bit more messy than we'd like to believe and I don't think I've covered the whole mess on this issue.

[Pim]

Interesting that one of the very few people who actually records in proper 24/96 has come up with a different answer.

http://www.realhd-audio.com/?p=6267

[David A]

I acknowledge that the comparisons/tests/studies that have been done comparing high res to CD quality have been equivocal in their outcome. Some have supported the existence of a difference, some haven't. I used to work in health and safety before I retired and one thing I learnt over time, looking at studies relating to possible health related effects from various sorts of exposure to possible substances and radiation with supposed adverse effects, is that it is extremely hard to design and conduct a high quality study that delivers results that are easily repeatable. People make claims on both sides of the argument and all provide observations to support their view and conduct various sorts of studies but then when those studies get analysed problems with the study design or conduct often come to light which end up casting the results in doubt. That sadly is the case with a lot of the disputes in audio and it's all to easy finding evidence that doesn't support the conclusions which then get drawn from it, and that's for the evidence produced on both sides. Sloppy work isn't confined to one side of any argument.

One obvious problems with studies like the Waldrup one is the fact that every person who responded listened using different equipment and there was no control on the quality of the equipment. If there is a difference there's no way of telling what proportion of participants listened on equipment that was capable of revealing the difference. That's one of the reasons why high quality studies are conducted under controlled conditions in which each listener not only listens to the same tracks but listens to those tracks played on the same equipment and that equipment is selected to ensure, as far as possible, that the equipment used is not going to mask any difference. Good quality studies aren't easy or quick or cheap to conduct and analysing the results properly is another problem area.

I'm not saying Waldrup's results are wrong but I am saying that his test design and procedure don't stand up to professional levels and that means that care has to be taken with the interpretation of the results. As for the results he reports, they're couched in anecdote, they don't include statistics of the number of correct responses vs incorrect responses, and most importantly they avoid any mention of whether any individuals managed to get everything right. If some people did get everything right, one would want to know what the circumstances, including their equipment choices, of their comparisons were and how those circumstances differed from those of the people who didn't do as well. If everyone listened under identical conditions and with identical conditions to anyone who got everything right, would the results of this survey be different? Good quality tests are not easy to design and conduct.

In any event, that issue is different from the point I made which was simply that saying we can't hear anything above 20 kHz so frequencies above that can't affect what people hear is incorrect because intermodulation of frequencies above the audible range can and does produce effects within the audible range. Intermodulation requires 2 or more simultaneous tones and tests which determined the limits of our hearing range were made with single tones so intermodulation effects don't occur. Simultaneous tones are a significant feature of music and can't be ignored. If you're going to test whether or not frequencies above 20 kHz affect what we hear when we're listening to music you have to conduct tests which use simultaneous tones if you want to have some hope of being able to generalise your results to what we can hear when listening to high res music sources. Even if we can hear intermodulation products from tests using simultaneous tones which includes a tone above 20 kHz in conjunction with another tone in the audible range that still won't guarantee that we can hear differences between high resolution music and CD quality music sources because music is much more complex than simple combinations of 2 different tones but you would learn things about how to set up a test using actual music from conducting tests using 2 tones that would help to design and set up higher quality tests using more complex sound sources including music.

My point, as I said, is that the question isn't as simple as it appears. I haven't seen any reports of a test or study that I think produces really convincing results for or against there being audible differences between high res and CD quality sources. Designing such a test or study isn't going to be a simple task and conducting it is also not going to be easy, and the test would have to be conducted under carefully controlled conditions because good studies have to be capable of being replicated by other researchers and consistently delivering the same result.

[Jean-Marie]

Every ABX studies have shown the same results, and they are the only ones eliminating expectation bias, that we all have whether we like it or not.

By the way, if frequencies above my hearing threshold can produce something that I can hear, this is not very good news for the quality of my reproduction chain, because it means that I have somewhere non linearities that are spilling back in the audible band.

I know that physics is counter intuitive in that case, but the closest your system is to perfection and linearity, the less likely you are to hear any difference between a red book and a higher resolution rendition of the same master.

Jean-Marie

[David A]

Every ABX studies have shown the same results, and they are the only ones eliminating expectation bias, that we all have whether we like it or not.

By the way, if frequencies above my hearing threshold can produce something that I can hear, this is not very good news for the quality of my reproduction chain, because it means that I have somewhere non linearities that are spilling back in the audible band.

I know that physics is counter intuitive in that case, but the closest your system is to perfection and linearity, the less likely you are to hear any difference between a red book and a higher resolution rendition of the same master.

Jean-Marie

The whole area of testing in audio is fraught with disputes and there are a lot of disputes about a lot of things. There isn't universal agreement about the accuracy/reliability of ABX testing but there isn't universal agreement about the accuracy/reliability of any other sort of testing protocol either. 

If you doubt that frequencies above your hearing threshold can produce effects in your audible range, look at the plots for the sort of tests I mentioned in John Atkinson's reviews in Stereophile. You'll see lots of distortion artefact spikes at 1 kHz intervals from 1 kHz on up from intermodulation between a 19 kHz tone and a 20 kHz tone. Are they audible? Take a look at their level relative to that of the 19 and 20 kHz tones. Audibility will depend on the level of the 2 test tones. Note that those test results apply to distortion produced in our gear. Now take a look at the distortion specs for your Devialet. They're well below the audibility threshold and my Devialet is the cleanest sounding amp I've ever owned. If I can hear distortion in my system it isn't coming from the Devialet but from somewhere else and I don't notice any distortion.

If you can find a copy of the Meredith Monk album "Our Lady of Late" and play the track "Slide" you will hear the tone of the wine glass she's rubbing and the note she's varying as she sings, and a third note which will appear to come from inside your ears. That third note is intermodulation occurring in your hearing. The note of the wine glass and that of her voice are well within the range of your hearing so this doesn't prove that you will hear something produced in this way if one or both tones are outside of your hearing range but it does demonstrate very clearly how 2 tones can generate a distinct and different third tone and the Atkinson test plots show that tones above the hearing range for most of us can produce tones that are well within the audible range. Is this a problem? I don't hear lots of people raising reports of problems of this kind and that says something, in fact it says a lot.

My point was simply to say that assuming anything above 20 kHz can't have an audible effect because it's outside our hearing range is problematic because sounds outside our hearing range can generate effects within the range we can hear. The question is how noticeable the difference between CD quality and higher resolutions is and we don't have a clear answer on that in my view. I buy high res files of music I really llke because I think I hear a difference, a subtle difference but one I like, and I can afford to buy the files. If I had the gear I had 20 years ago I doubt I would hear the difference I think I hear and I wouldn't be buying high res files. I'll tell people that I think high res makes a difference but I won't tell them that it's proven that it makes a difference. I try to be honest about the state of the debate. That's the best I can do. I weighed in here with my original response simply because assuming that anything above 20 kHz CAN'T make a difference because we can't hear above 20 kHz is overly simplistic when that fact was determined with single test tones and almost every piece of music involves harmony, ie several tones at the same time, and when 2 or more tones occur simultaneously intermodulation products can be generated within the audible range. That means that there may be some audible effects from sounds in music which fall outside the accepted range of audibility. I have no doubt that any such audible effects are going to be subtle but they are theoretically possible.

I'll tell one story to illustrate the difficulty of testing for audibility of effects. Years ago when Sony and others were trying to come up with copyright protection strategies for CDs, people were trying to devise "watermarks", signals which could be buried in the audio signal on a CD and identified in copied material but the problem was designing a watermark which wasn't audible because an audible watermark would be regarded as a degradation and distortion of the music. Lots of listening tests were involved because that's the only way you can test for the audibility of a watermark. One company came up with a watermark they claimed was inaudible and they pointed to extensive, well conducted tests for which the results failed to show that the people tested could hear the watermark. They started demonstrating this publicly by conducting demonstrations at audio shows and giving the listeners a card on which they could record their results with those results being analysed and reported to the participants at the time. Several of these demos were apparently conducted with the same result, no proof of audibility, and then at one test where the collated results showed exactly the same thing there was one participant who got every test comparison right. That was a non-random result par excellence. They asked that participant what he was listening for and hearing and he told them. Once they knew what to listen for they heard it also, and anyone told what to listen for could also hear it and get every test right. The watermark was most definitely audible but people who didn't know what to listen for and who weren't listening for it didn't notice it. Audibility is a complex issue and designing and conducting really good and reliable tests is most definitely not easy.

If you want my definition of a really good, reliable test then I'd say it's a test that puts the dispute to rest, one which delivers a test which everyone accepts. It can be done but it can take a lot of time and a lot of money and a lot of tests which don't put the issue to rest in order to come up with a test process that can deliver the goods. There have to be reasons other than simple academic or scientific interest to go to those lengths and those reasons tend to boil down to the return you can make on the investment it takes to get the result. That kind of return on investment usually isn't found in the audio business so if we're going to see that sort of test then it's going to have to be conducted for other reasons than the one we're interested in. These days that's likely to mean that it's going to have to be related to something like electronic surveillance for military or security purposes and it could take some time for people outside those areas to become aware of it. 

For what it's worth I'd love someone to produce a study that resolves the question regardless of whether the result says that I was right or that I've been wasting my money on high res files. Audio advances when disputes like this get clearly resolved and I'm in favour of that. The prospect of being wrong doesn't worry me. I've been wrong and spent money in audio on things I later decided weren't worth it before. No one gets it right all of the time. 

The only thing you said that I might disagree with you on is your statement that "the closest your system is to perfection and linearity, the less likely you are to hear any difference…". In my experience the better your system gets the less it masks subtle differences and the more likely you are to hear small differences you didn't notice before.

[Confused]

First to say that I do not have any strong views with respect to the benefits of "high res" formats or similar.  When I am buying something new, I will happily get the 24/96 version, why not?  But if there is a significant price difference somewhere, I would probably opt for the cheaper version.  As an example, the last "high res" album I bought was one price for the 24/96 version and a higher price for 24/192, I was more than happy to settle for the 24/96 version.  

I am interested in much of what has been written by David A.  To add to this, I was reading some information recently about digital to analogue conversion and issues with digital filters and similar.  This is highly complex and mathematical stuff that does not need to be repeated here, but in conclusion, there are some technical reasons why 24 bit files can solve some minor issues that can negatively the impact digital to analogue conversion of 16/44.1 files.  So maybe there is a small benefit from hi res files, as to how audible this might be is open to debate.  I would take the view that as there are no obvious negatives, you might as well go for 24 bit if there is no significant financial penalty.  If 24 bit is significantly more expensive, I'd rather give the difference to charity or buy a beer.

I must admit that I have had some fun thinking about the intermodulation effects that David mentions.  Consider an instrument in a musical performace that produces frequencies above 20kHz which in turn create intermodulation effects within the audible range.  These audible intermodulation effects could be captured by a microphone and reproduced with a 16/44.1 digital file.  If you used a 24/192 file and a system that could reproduce the content above 20kHz, then this could recreate the intermodulation effect in your room, but at the same time would still reproduce the originally recorded intermodulation effect so you would get the intermodulation effect twice.  Maybe 16/44.1 would actually be more accurate in this regard?

Fun to think about, but my personal experience tells me that the difference between 320kbs, 16/44.1, 24/192 or whatever is very small.  Or to put it another way, very nicely recorded material can sound spectacular when reproduced from a 320kbs file.  In the same way, I have some 24bit recordings that sound awful, and would still sound awful compressed to 320kbs.

That said, I think if you go below 320kbs things do get audibly worse.  I very often listen to music via YouTube.  This is for "music discovery", plus I follow a music thread on another forum where people post YouTube links to suggested music.  I listen to these via my iPad and Airplay.  Sometimes these YouTube tracks can sound quite superb, very often I am surprised at just how good they sound, considering they are 128kbs or something at best.  However, I have tried YouTube versions of tracks that I am familiar with at 16/44.1, and yes, the YouTube versions are obviously inferior, loss of detail, a bit of extra bass bloat, and so on.  Get to 320kbs, the margins get very small I think.  But again, the genuinely big differences are in the mastering, not the file format.

For those interested in comparing, I think you need files from absolutely identical masters, but in different file formats.  Listening to random tracks in different file formats will tell you nothing because the difference in the mastering is so large.  One thing to try is to take a favorite 24/192 track and make some copies converted to 16/44.1 and 320kbs.  Software such as dBpoweramp can do this quite easily.  What you have then is different audio files formats, but demonstrably from the same source.  Maybe some folk will be able to tell the files apart, but I would doubt anyone who states the differences are huge or obvious.  Don't take my word for it though, or anyone else's, it is best to try yourself.

On a similar topic, I quite enjoyed this from Archimago:

http://archimago.blogspot.com/2014/06/24...art-i.html

http://archimago.blogspot.com/2014/06/24...rt-ii.html