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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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  • #16
    Wide bandwidth and sonic character

    Originally posted by STHLS5 View Post
    In this case, looks like nothing much above 10kHz [in the audio itself].ST
    That's possible.

    How could we prove this in our usual quick, low-cost, low-hassle way?

    I saved the frequency-shaping envelopes A,B, C and C1 in the audio editor when I created them. So I can recall them and apply them to any other audio at will. So, how about if I apply the same preset effects to ...
    1. Wide bandwidth music that we pre-check has components extending up to at least 20kHz (to be sure that there are actually tones present to boost) and/or
    2. Non-musical hiss or noise which we also pre-check for truly extended bandwidth to eliminate music as a variable

    and place them here as clips then see if we can hear the C/C1 effect on the extended bandwidth source. If we can then hear C/C1, that validates our hearing acuity. Agree?

    There is also one aspect I want to check with you. Would you feel comfortable with the concept that whichever component in the audio chain exhibited the sonic character A, B, C/C1 (from the microphone right through to the speakers at home) would impose that character on all subsequent component steps right down to the listener? For example, if the microphone had sonic character B (refer to clip), regardless of whether the home listener's CD, CD transport, DAC, amplifier, stands, interconnects, room treatment, biwire links or speakers were perfectly flat in themselves (like ref. clip Q), audio character B would be evident to the listener?

    In simple language, 'once the damage is done it cannot be undone' regardless of how much time or money the audiophile throws at 'remedying' the undesirable tonality issue. It would imply that the sound quality perceived by the home listener can never, ever improve upon that of the recording itself.

    That would suggest, if true, that the most crucial 'components' in the hi-fi chain are the sonic characteristics of the recording microphones and hall acoustics. And we know that they are far from flat.

    Comfortable with that idea?
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

    Comment


    • #17
      Is hi-fi about music? Maybe not.

      A bit unrelated perhaps, but reading some of the responses here made me wonder;

      Why do I get the feeling, that people who own a hi-fi installation that is probably of better quality than that of 99% of the population, seem to enjoy music less than those 99%. Ironic, no?

      Comment


      • #18
        Great thread. My responses to the clips was exactly the same as ST's.


        Originally posted by A.S. View Post
        ...and place them here as clips then see if we can hear the C/C1 effect on the extended bandwidth source. If we can then hear C/C1, that validates our hearing acuity. Agree?
        Yes. (Although if we can't hear C/C1, that doesn't validate our hearing non-acuity as it were, if our PC speakers at home fail to dish out much of anything over 10 kHz).

        Originally posted by A.S. View Post
        For example, if the microphone had sonic character B (refer to clip), regardless of whether the home listener's CD, CD transport, DAC, amplifier, stands, interconnects, room treatment, biwire links or speakers were perfectly flat in themselves (like ref. clip Q), audio character B would be evident to the listener?
        Yes definitely.

        Originally posted by A.S. View Post
        In simple language, 'once the damage is done it cannot be undone' regardless of how much time or money the audiophile throws at 'remedying' the undesirable tonality issue. It would imply that the sound quality perceived by the home listener can never, ever improve upon that of the recording itself.
        Not sure about that... if the recording microphone boosted a certain frequency range, could not the home listener with a good equalising deck bring back the response to something like flat?

        Originally posted by A.S. View Post
        That would suggest, if true, that the most crucial 'components' in the hi-fi chain are the sonic characteristics of the recording microphones and hall acoustics. And we know that they are far from flat.

        Comfortable with that idea?
        Yes, definitely happy with that.
        Ben from UK. Harbeth Super HL5 owner.

        Comment


        • #19
          Originally posted by BAS-H View Post
          ....Not sure about that... if the recording microphone boosted a certain frequency range, could not the home listener with a good equalising deck bring back the response to something like flat? ......
          This is not actually possible in the complete sense you imply. It is not possible to remove every molecule of your presence from the scene of the crime and it is not possible to completely reverse whatever undesireable sonic corruption proceeding stages in the audio chain have imposed. Just consider the effect that the frequency boost has on harmonics of the boosted frequency band .... how do you remove boosted harmonics even if you can cancel the boosted fundamentals?

          Furthermore, as stated in the matrix here, tone controls are anathema to audiophiles. They represent an unspeakable crime against audio - a truly barmy position. Those that can get along without the occasional touch of the tone control, are surely putting themselves in a position where they have absolutely no ability to correct for technical or artistic blemishes in the audio chain. Their position is the same as removing the colour control from the domestic TV: the viewer/listener must then take whatever is dished-up to them without complaint, like it or lump it. A very curious state of affairs.

          Can we assume that only a smattering of audiophiles actually have tone corrections controls on their equipment? Can we also assume that those controls offer only a very broad-brush approach that gives only a generalised boost/cut across quite wide audio bands like 'bass' and 'treble'? Can we anticipate that unless the preceding corruption is of exactly the same frequency-shaped profile as the generalised fit-all tone controls, that the effect of applying a generalised solution to a specific problem may to actually make the resulting sound even less attractive?

          Furthermore, you have now touched on one of the most serious issues in audio - the limitations of microphones which compared to every other component in the chain (and second only to the speakers and pickup cartridges) are very challenging devices, as you would expect for any electo-mechanical system.

          I was back in the studio today, and asked three top class sound engineer (without priming them) for their opinion on which audio component they believed had the most profound influence on the audio chain right through to the listener. The unanimous opinion was, obviously, that it was the selection of the microphone, where it was placed and its condition and serviceability. In their view, the second most important factor is the treatment of the listener's room, and they referred me to the SOS DIY diffuser article which is their 'bible'; I'm sure we've posted here before (anyone?).

          As a matter of interest, if you were selecting a microphone for a pro recording, what sort of sonic characteristics would you shortlist? What unwelcome characterisitic (limitations) would you be very much aware of? (Your answer to this very much relates to your belief above about being able to cancel-out preceeding sonic aberations.)

          We'll return to analysing the clips shortly.
          Alan A. Shaw
          Designer, owner
          Harbeth Audio UK

          Comment


          • #20
            The usefulness of pink noise

            Back to why we couldn't seem to hear any effect for eq settings C or C1. It's possible that there just wasn't any or enough energy in the music reference Q to boost to audibility. Or it could have been the speakers/headphones on which you were listening. Or it could have been that at our age, we just can't hear much above 10kHz .... or maybe a little of all three. So we need to do some elimination.

            Let's forget about finding a suitable wide-bandwidth music clip and jump straight to the quick solution from experience. We'll use pink noise. Pink noise is usually generated as the bright, sharp 'white noise' hiss you hear when an FM radio is off tune, but then it's processed to have a particular sonic character. You can see from the attached thumbnail, that pink noise has a diminishing energy gradient from low to high frequencies - and as you can hear it has much less 'top' than the white noise of an off-tune FM radio. Pink noise is a very useful test tool for quick and accurate analysis of audio related issues. Although pink noise sounds distinctly bass heavy (or lacking in high frequencies which is really the same subjective effect) in fact, there is far more high frequency energy in pink noise than western classical music. Hard to believe? How can it sound so dull and yet contain more HF energy than classical* music? It's all about total energy, not instantaneous energy.

            Have you ever taken a long exposure photo where the camera shutter is open for many minutes? Perhaps of the night sky? What will be recorded is every event between the opening and shutting of the lens. Events which were slow moving and/or especially bright (or dark) will have made more of an impression on the image sensor (film in the old days); fleeting events such as a meteor flashing past will have little influence on the scene, because they just don't have enough luminance to really effect the average brightness. So what we will see when we examine the image is that the scene will be weighted or biased away from fleeting events towards more persistent events. In audio terms, the persistent events will be the almost continuous low frequencies (cello, double bass etc.) and the fleeting events will be cymbal crashes. So .... if we set the audio analyser to take the audio equivalent of a long exposure picture of the audio over an entire performance (say, the complete 23 minutes of Symphonic Dances) we can determine how much of each frequency is present across the whole piece. And as a generalisation, most western classical music sound about the same, and unsurprisingly has about the same spectral content. Using pink noise may sometimes saves us having to critically listen to music over a long period: just a few seconds of pink noise can tell us as much, or possibly more, than having to carefully absorb the entire performance. Every seconds worth of pink noise is alike every other seconds (unlike music).

            Here is computer-generated pink noise: have a listen and see if you find it seems to be lacking in high frequency sparkle compared with music we like ....

            Loading the player ...
            Clip P: stereo pink noise

            It really doesn't have the characteristic clarity and brightness of tone that we associate with good music on a good system does it.

            OK, now let's open the shutter in the audio analyser and make a long-exposure capture of pink noise playing. (Refer to pinkshape-sc.jpg). Ignoring the minor wiggles we can see that there is a straight-line function, and that gradient precisely defines 'pink noise' to acoustic people. Pink noise is not just any old noise: it is scientific noise.

            Next I played into the audio analyser the entire 23 minutes of Symphonic Dances. Ignoring the difference in vertical offset between Dances and pink noise (I didn't calibrate the analyser as we're working in dBs so no need to) I've plotted Dances on the same graph as the pink noise (ref: dances-pink-sc.jpg). You can see that below about 150Hz the pink noise has much more bass (the green trace is off the top of the image) than Dances averaged over 23 minutes, and perhaps surprisingly, above about 2kHz, the pink noise has much more high frequencies - six times more (20-5dB) at 10kHz than the averaged musical performance. Surprised just how little total high frequency energy there is in western classical* music? So our initial impression playing the pink noise clip P above that it was lacking in HF was in fact, wildly incorrect. It has roughly six times more.

            Are you Ok with the idea that we can substitute listening to a short blast of pink noise for listening to many minutes of music when we are trying to compare general response shape characteristics? There is certainly more than enough HF in pink noise, and as we can see, its bandwidth extends right out to beyond 20kHz without the droop we see with classical music. It's going to allow us to nail either our hearing or speakers/headphones as the reason why we can't hear the effect of clip C or C1.

            For my own curiosity, I applied a filter having the overall shape (the three orange lines) of the Symphonic Dances profile onto the pink noise (as per clip P above) and made it have the same sonic spectrum. This now audibly exposes how little HF total energy there is in classical music. Compare with the pink noise clip above. As I have said for many years, the crucially important part of music is the midrange - the speech band - where almost all of the energy is concentrated. The 'tweet' bit is a non-essential luxury, as listening to AM radio confirms.

            Loading the player ...
            Clip S: stereo pink noise shaped to have the same energy profile as 23 minutes of classical music


            * Pop music has an entirely different spectra with much more top end. If you were presented with a plot of audio long-exposure of pop or classical music, you could identify them with certainty by the gradient of the curves.

            >SUBJECT CONTINUES ON POST #29

            [2.6 hrs.]
            Attached Files
            Alan A. Shaw
            Designer, owner
            Harbeth Audio UK

            Comment


            • #21
              Good explanation about pink noise

              This is the first time I really understood the importance of the pink noise and its relation to music. What it used to be just the sound of water gushing down the waterfalls, now have a whole new meaning to me. Thanks Alan. Your explanation about the pink noise and its usefulness is better understood than the technical explanation of Wikipedia.

              ST

              {Moderator's comment: Are you OK with using pink noise as a revealing test signal for comparing the audio clips A, B, C, C1?}

              Comment


              • #22
                Yes- go ahead with pink noise

                Originally posted by STHLS5 View Post
                ....{Moderator's comment: Are you OK with using pink noise as a revealing test signal for comparing the audio clips A, B, C, C1?}
                Yes, that's what I was thinking of asking you to do but wasn't feeling good about it after seeing that you took a good 2.6 hours to make your point. Would appreciate if you could indulge me.

                ST

                {Moderator's comment: Pleasure. Alan will make time over the next days.}

                Comment


                • #23
                  Longer term conditioning through exposure to sound

                  Very interesting thread Alan, thank you.

                  nb The following are observations which in no way require reply as they are slightly to one side of the main topic

                  Have just got round to listening to all the clips and realise that I may have a slightly different take on things in that both before and after listening to the other clips, reference Q (the BBC concert sound, ex-studio) sounds 'normal' to me.

                  My office set-up is such that I have a relatively 'hi-fi' system playing all day, and what it is playing all day is BBC R3. Not all of the output is live broadcasts of course but the 'BBC house sound' heard through my office system is something that is deeply engrained. I am guessing that that being the case all of the manipulated clips sounded 'other' to me.

                  The second point is that if asked I would have said the manipulated clips were lacking bass and 'body' rather than having an excess of top; this may simply be a cup half full/cup half empty - tomaytoe/tomahtoe thing - but it suggests that I would be looking in the wrong direction if looking to change things, ie I would be looking to bring up the bass rather than take down the top.

                  Lastly - I was struck by STHL5's comment in relation to waterfalls; I would be much happier sat on the grass alongside waterfall 'S' {pink noise shaped to have classical music energy} than waterfall 'P' {raw pink noise}.

                  Considering the overall sonic spectrum of different types of music is not something I have ever done - and wouldn't have done had it not been presented in this way - but I suspect it may well be fundamental in the choices I make about the music I listen to.

                  Comment


                  • #24
                    Limitations of Microphones

                    Apologies for going back a step.

                    Originally posted by A.S. View Post
                    As a matter of interest, if you were selecting a microphone for a pro recording, what sort of sonic characteristics would you shortlist? What unwelcome characterisitic (limitations) would you be very much aware of? (Your answer to this very much relates to your belief above about being able to cancel-out preceding sonic aberrations.)
                    Thanks for your explanation. You are right of course.

                    I'm struggling, but going to stab a guess at directionality. I would think a mic that picks up unwanted reflections would be very hard to correct after the recording event.
                    Ben from UK. Harbeth Super HL5 owner.

                    Comment


                    • #25
                      The nature of microphones

                      Originally posted by BAS-H View Post

                      I'm struggling, but going to stab a guess at directionality. I would think a mic that picks up unwanted reflections would be very hard to correct after the recording event.
                      You are very close. Did you know that the frequency response of even the best studio mics depends upon the angle of incidence of the sound it picks up? That is a very serious issue. Can you visualise why that would be so?
                      Alan A. Shaw
                      Designer, owner
                      Harbeth Audio UK

                      Comment


                      • #26
                        Microphones and soundwaves

                        A.S

                        You ask as to why angle of microphone may affect its response at different frequencies ? I'm feeling rather embarrassed that as someone who considers himself to be interested in musical reproduction in the home I know vanishingly little about the way it is recorded.

                        I assume this is related to the combination of the transducer within the microphone and its response to different wavelengths of sound, and the way in which those wavelengths are conducted to the transducer.

                        An analogy might be the human ear, which has auditory potentials provoked in the hair cells of the cochlea stimulated by movements of the ear drum. The drum is moved by sounds that are transmitted via air (down the ear canal) and through bone via (via the skull).

                        If a tuning fork is placed on the mastoid process behind the ear it can be heard, but if held adjacent to the entry of the ear canal (the external auditory meatus) it can also be detected. However the sound is different, the prominent frequency of tone can be detected at both sites, but when conducted through air the sound is brighter with more high frequency harmonics detectable.

                        Am I on the right track ?

                        Comment


                        • #27
                          Originally posted by 1ryal View Post
                          ... You ask as to why angle of microphone may affect its response at different frequencies ? I assume this is related to the combination of the transducer within the microphone and its response to different wavelengths of sound, and the way in which those wavelengths are conducted to the transducer....
                          Pretty much. I think it's even simpler than that.

                          The interesting thing is that the first (microphone) and last (speaker) steps of the audio chain represent the conversion of sound to electricity and electricity to sound. They (normally) use circular transducers and the basic physics of circular sound receiving/sound generating discs predicts a relationship between the diameter and various frequency related issues. Because of that very issue, in loudspeakers we are familiar with the idea of on and off axis frequency responses (which may, even a few degrees off axis be radically different).

                          Microphones have the same on/off axis issues as loudspeakers but principally because the microphone diaphragm diameter is so much smaller than a woofer, (typically about 25mm compared with 200mm) that pushes the on/off axis issues upwards in frequency.

                          The other critical factor in shaping a microphone's performance on/off axis is the design of the microphone housing itself. Early (capacitor) microphones were inefficient and the fragile capsules were mounted in huge cases partly to protect them and partly to house the essential and large/hot tube-based amplifiers close to the capsules. In the 70s solid state electronics arrived and this miniaturised the electronics and allowed the microphone case body size to be reduced. Then pencil-like microphones were introduced with the capsule mounted at the end of a thin body, the body being in effect behind the diaphragm - an ideal situation. Now, thanks to fads and fashions in the studio market we have a complete reversal to big microphone bodies, large diaphragm capsules claiming a 'big warm sound' and the microphone once again presenting itself as a significant object in the sound field it is collecting and which, logically, it should be completely independent of.

                          Early (ribbon) microphone - huge body, no internal electronics

                          Early capacitor microphone - large body, internal tube electronics; Wonderful pictures of entire internal structure. Imagine the reflections off structural parts near the capsule and the capsule ring itself.

                          Mid period pencil-like capacitor microphone, capsule on end of amplifier in stick

                          State of the art modern small-body capacitor microphones - note mention of on/off axis response

                          Modern big-body microphone

                          That's all on mics for now. We'll return to their sonic characteristics later. Just be aware that they stamp their sonic signature on the entire audio chain, and that character cannot be completely reversed or negated: it's DNA will remain.
                          Alan A. Shaw
                          Designer, owner
                          Harbeth Audio UK

                          Comment


                          • #28
                            Mics: Response and Angle of Incidence

                            Originally posted by A.S. View Post
                            You are very close. Did you know that the frequency response of even the best studio mics depends upon the angle of incidence of the sound it picks up? That is a very serious issue. Can you visualise why that would be so?
                            Yes indeed! Sound waves at an angle will be further apart from one another. Fascinating.
                            Ben from UK. Harbeth Super HL5 owner.

                            Comment


                            • #29
                              Listening to modified pink noise clips ..... (cont. from post #20)

                              In post #20 I gave four examples of the high-frequency response characteristics found amongst current loudspeaker designs by superimposing those characters onto a musical excerpt. Listeners found it difficult to clearly identify the audible effect of the character of clip C and C1. I suggested that this could be due to, amongst other things, the limitations of hearing acuity, cheap PC speaker or headphones or the relatively limited HF content of the musical except at the upper end of the audio spectrum, which was subsequently proven by time-averaging the entire clip for spectral content. The frequency graph of the measurable boosts depending upon frequency are attached again.

                              I then proposed applying the sonic frequency characteristics of A, B, C and C1 to standard pink noise, which with a more extended and energetic top end, may be a more revealing test signal for us to hear the effect of selectively boosting the higher frequencies. Here they are:

                              First, a reminder of the raw, unadjusted stereo pink noise, our experimental control:

                              Loading the player ...
                              Clip P, our reference sound (again). This is what it should sound like: almost perfectly pink-noise 'flat' to >20kHz.

                              Now, applying frequency characteristic A to the above pink noise reference:

                              Loading the player ...
                              Clip T

                              Applying frequency characteristic B to the above pink noise reference:

                              Loading the player ...
                              Clip V

                              Applying frequency characteristic C1 to the above pink noise reference:

                              Loading the player ...
                              Clip W

                              Applying frequency characteristic C to the above pink noise reference:

                              Loading the player ...
                              Clip X

                              I suggest that turn facing away from your speakers to hear how the sound bounces off hard objects in your room - that may amplify the differences even more than a direct face-on listening. As an experiment you may wish to play the reference clip P a few times, repeatedly, to acclimatise yourself.Then work your way through the others with an occasional switch back to P. Then when you have identified the sonic character of a particular clip, play that one continuously for a few minutes (sorry no loop button) and observe your longer-term exposure experience. Then after a really long exposure, switch back to ref P and see how you feel.

                              Remember! You must not have more than one clip playing at any time. You must pause one and start another. (HTML5 will unfortunately allow all to be played simultaneously which negates the experiment).

                              That's it. I'm now off to the local pub to a 70s disco night: without doubt the very best music known to man!

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

                              Comment


                              • #30
                                Fast or slow?

                                (To Mod, pls delete if this is a diversion but I just needed a non audiophile's opinion..)

                                Out of curiosity, I asked my children to give their opinions about these clips. I just wanted to know what the relatively unadulterated young ears hear. Do these random noise clips have any meaning to them?

                                According to my son, his exact words are as follows:-

                                1) P sounds like fading but T is "lower" but sharper than P.

                                2) T is lower than V.

                                3) W is SLOWER and lower than V.

                                4) X is slower than V.

                                He is unable to explain what is lower ( no, he wasn't referring to volume) but he usually refers low to mean low pitch or a deeper bass. What struck me was his description of W and X as slower. Isn't this a common description among audiophiles to describe some speakers to be 'fast or slow?'


                                ST

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