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Identifying system components for their sonic neutrality should logically proceed from the interpretation and analysis of their technical, objective performance. Deviations from a flat frequency response at any point along the signal chain from microphone to ear is likely to give an audible sonic personality to the system at your ear; this includes the significant contribution of the listening room itself. To accurately reproduce the recorded sound as Harbeth speakers are designed to do, you would be best advised to select system components (sources, electronics, cables and so on) that do not color the sound before it reaches the speakers.

For example, the design of and interaction between the hifi amplifier and its speaker load can and will alter the sound balance of what you hear. This may or may not be what you wish to achieve, but any deviation from a flat response is a step away from a truly neutral system. HUG has extensively discussed amplifiers and the methods for seeking the most objectively neutral among a plethora of product choices.

HUG specialises in making complex technical matters simple to understand, getting at the repeatable facts in a post-truth environment where objectivity is increasingly ridiculed. With our heritage of natural sound and pragmatic design, HUG is not the best place to discuss non-Harbeth audio components selected, knowingly or not, to introduce a significantly personalised system sound. For that you should do your own research and above all, make the effort to visit an Authorised Dealer and listen to your music at your loudness on your loudspeakers through the various offerings there. There is really no on-line substitute for time invested in a dealer's showroom because 'tuning' your system to taste is such a highly personal matter. Our overall objective here is to empower readers to make the factually best procurement decisions in the interests of lifelike music at home.

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Feb. 2018
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'How loud?' versus how far you turn the volume control

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  • 'How loud?' versus how far you turn the volume control

    General rule:

    If 7 o/clock is amplifier volume fully off, CD (or any input) should not sound loud until the volume control is rotated to about 2 o/clock or more.

    If 7 o/clock is amplifier volume off, and CD is loud at 8 o/clock or 9 o/clock rotation of the amp volume control, there is something very wrong with your system. The concept of loudness and rotation of the volume control is that a well designed system arranges for a progressive increase in loudness to match that of the ear's characteristics: ideally fully rotated is fully loud. The volume range should not be bunched together at the bottom end of the volume control: that is not how it should be at all. That is evidence of a serious mismatch in signal levels between the CD recording, the CD player output and your amplifier input.

    Fully loud in the bottom 20% of the volume control range means that the levels of the CD output v. the preamp input, preamp output/power amp input expectation are not correctly matched. This will seriously compromise the possibility of high fidelity sound and introduce the almost certainty of amplifier overload, clipping, a hardness and harshness of sound "digital glare" and even damage your speakers. Your system will sound hard and unnatural and for this reason alone, you may prefer the sound of vinyl, which sounds loud at a correct 2 or 3 o'clock rotation of the volume control.

    If your system goes from silent to loud over just a small percentage of the amp's volume control range (digital, stepped or analogue) find out why and resolve it. The volume control is not a switch. It should have a progressive, smooth action and give progressively more loudness from typically 7 o/clock to 5 o/clock.

    Resolving this mismatch is the best investment in high-fi sound that you will ever make and it may cost you nothing.

  • #2
    Inevitable channel imbalance at very low volume settings

    I had an LFD zero LE III and it was unbearably loud. So I sold it.

    My Rega Cursa3 starts at 7 o'clock and now at 23.30h I'm listening at 11:30 o'clock on the dial and it's not too loud. The Cursa3 pot is divided in 80 1dB steps and there is no significant channel unevenness at low listening.

    But that is unnecessary because for listening at low volumes I'm already past the range where many volume pots have the greatest channel unbalance.


    • #3
      Alan's zero level test tones

      It would be helpful to have Alan's 0dB (fully loud) signal files to decide whether the system is playing loud or too loud at a given rotation. We'll have just to wait till he has some spare time. I read he's having to deal with visitors.


      • #4
        Loudness tests: start with your PC speakers, here

        OK, I made an early start today to make these tones, before departing for the weekend to see our granddaughter.

        First, as an MP3 file, just to familiarise you with the concept. It would be a good idea to experiment with the procedure of listening for distortion on your PC speakers before I supply WAV files to burn to a CD disc to investigate your hifi system (next week).


        STEP 1: Familiarisation with distortion - this gives you an idea of what to listen for

        STEP 2: Explanation of the tone/volume ramp idea

        STEP 3: The test - the tone/loudness ramp itself

        You may wish to rock the volume control up/down for any particular tone level to find the point of rotation of your volume control at which distortion is audible and to mark the front panel with a sticky note or make a drawing of rotation angle versus detectable distortion.

        The three WAV file source versions of the above MP3 files can be found on post #16, below.

        We cannot be responsible for the consequences of playing test tones over your audio equipment at high levels and without due care. If you are in any doubt about your ability to follow the instructions and apply due caution, please do not commence Step 3.

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


        • #5

          Thank you and have a nice weekend.


          • #6
            Volume control design

            PLEASE do be aware that so many mechanical potentiometers used these days in modern audio equipment seems to have a 'reverse taper law' on the way the control operates, giving all on a CD source in the first third to half of rotation and very little gain change in the second half of rotation. I think this has continued due to the rather old designs still being packaged in new cases and presenting these as new models. In my opinion, this is a left-over from the time before CD, where many line sources (tuners, tape decks etc.) were around a third the voltage output of a CD player. Phono stages were matched to these old line sources, leaving CD as the odd one out: louder than the other sources.

            Seriously, I'd have thought that thirty odd years on from CD being introduced to market, and with modern phono stages coming along with new design thinking, this effect via inappropriate potentiometer choice would have been banished to history.

            The power amps I use (vintage models with pro roots) all have gain controls on them. I set the overall system gain on these to around half way on the controls and adjust 'volume' via the preamp, giving me loads of low-volume usability...


            • #7

              Forget the Hi-Fi, your Grandaughter is a little beauty.


              • #8
                Loudness and rotation - Rega

                Unusually, the Rega amps have usable volume control ranges where loud is around 12 - 1o/c. I have just taken delivery of two new Pathos amps and these have volume pots with 180 steps. Normal loud volume with these is around 120 - 130, so there is plenty of control at low volumes.


                • #9
                  CD player output voltage trim

                  At my side, how much turn on amp's volume control was much dependent on recordings and vary album by album. To set an universal volume on my amp side for all albums like a mission impossible. I mostly listen to CD. I have a Marantz CD17 MKIII player for 10 yrs and only few months ago found its adjustable line output volume control on its remote control is very useful (14 bars fully light up is default volume with every two press down reduce a bar). Now I do not really care how much turn on my LFD Zero LE III amp. I am using that feature in this way: set the amp volume control to some way I know is quite loud, between 8-9 O'clock (6 O'clock is fully no sound), then I turn on my sound level meter in my phone (Android apps, smart tool sound meter) to measure playback sound level at listening position (about 7 ft away from center of both speakers).

                  I adjust the CD player line output volume, usually between 1 to 3 bars down, until the loudest playback is measured as 83-85 dB for classical music, around 80 dB peak for chamber/jazz/other musics and around 75 dB peak for vocal/song. I find this way to control volume is very satisfying and also prevent I listen too loud.
                  "Bath with Music"


                  • #10
                    Originally posted by hifi_dave View Post
                    Unusually, the Rega amps have usable volume control ranges where loud is around 12 - 1o/c.
                    Unusually as in it is at a later time than is common these days or earlier?!

                    I find that for almost all modern amps that I have used, I don't even know how loud they can go - never had reason to ever turn the volume beyond 11-12 o clock. Gone are the days of listening to them at normal levels at 2 pm - indeed that now gives rise to a suspicion that the amp is underpowered.

                    The only exception I know of in personal use is a Sonos Connect Amp with 55wpc. Normal listening is at about 65% on the volume slider control on the remote. Normal in my case maxes out on the louder side of moderate - say about 90db, approximately measured at 4 metres. On the other hand, a NAD 50wpc goes just as loud between 10 and 11.


                    • #11
                      The volume/turn illusion

                      Originally posted by Kumar Kane View Post
                      I find that for almost all modern amps that I have used, I don't even know how loud they can go - never had reason to ever turn the volume beyond 11-12 o clock. Gone are the days of listening to them at normal levels at 2 pm - indeed that now gives rise to a suspicion that the amp is underpowered.
                      Ah well, you have hit the nail on the head there.

                      The graduation of the volume control should not be decided by marketing people; it's not a matter of just arranging the rotation of the volume control to give the illusion of power, as you yourself admit above. The volume control should not be a sales inducement tool, as it has now become. The design of the volume control 'rotation' v. power v. loudness is rightly a wholly engineering matter. The purpose of the volume contol is to match the incoming voltage (from an external source) to the power potential of the amplifier in a graduated and logical way so that the maximum power is, ideally, supplied when the volume control is at maximum, and not before.

                      That's precidely the same consideration of how to graduate the throttle control on a car. Logically, the harder the user presses down on the throttle control, the faster the car should go, with the maximum speed only when the throttle is depressed fully. Imagine the danger and confusion the driver experience if he went from zero to full speed in the first 20% of the throttle peddle range: undrivable.

                      Consider this: the amp volume control should be arranged in exactly the same way as the throttle controls in an aircraft; maximum speed at maximum throttle, fully forward. Full power, the tap fully open, full volume.

                      You can see how a volume control should be arranged here, in this 747 take off here. Also Concorde take-off (advance to 5 mins 30) here and in-flight, from a mid-power setting up to full power again to accelerate to supersonic speed (advance to 8 mins) here. Again, progressive forward motion of the throttle control is proportionate to power, as it should be with a domestic audio amplfier's volume control.

                      In the pro-audio world, where there is a proper level (gain) structure through the recording and mixing process, we can see how the mixing engineer trims the gain of signals passing through his mixing console before they arrive at the channel volume slider control (fader) so that the volume control is always operated 3/4 or so up its loudness range: this is technically correct and gives the best signal to noise ratio. Advance video to about 5 mins, and see this gain trimming in operation through the various EQ effects. Video here and note position of fader controls. And again, here, where the volume faders are correctly operated towards the top of their range.

                      If the volume control is so misdesigned that most of the loudness is at the bottom end of the volume range, then the marketing people have overridden the engineers and forced them to intentionally create the illusion in the non-technical user of an amplifier "... punching above its weight". They've done this by selecting the wrong type of volume control resistance versus rotation - there are several resistance laws (output versus input versus rotation angle) to choose from when ordering volume control potentiometers from the supplier.
                      Alan A. Shaw
                      Designer, owner
                      Harbeth Audio UK


                      • #12
                        Request for .wav files

                        Originally posted by A.S. View Post

                        I will make .WAV versions of these three files available next week for you to download and burn to a CD disc.
                        Would you be so kind to prepare them asap please? Very interesting experience.

                        {Moderator's comment: Alan is away from home and cannot produce these files until he returns.}


                        • #13
                          In the studio

                          As I've mentioned, the gain structure of domestic audio equipment is a lawless, unregulated jungle, with inevitable consequences of reduced fidelity. Equipment cannot be strung together at home with any realistic expectation of genuine fidelity across the audio frequency and dynamic ranges. In the studio, voltage levels are strictly controlled, because professional sound people have been aware of the importance of regulated level since the 1920s: that's about one hundred years. Home audio enthusiasts are unaware of the importance of a strategy to carefully consider and then set voltage levels through their equipment, and they pay for that ignorance.

                          There is an excellent video here explaining the importance of level, gain and gain structure; here.
                          Alan A. Shaw
                          Designer, owner
                          Harbeth Audio UK


                          • #14
                            An amplifier solution?

                            Another raison d'Ítre for a Harbeth amplifier?

                            I think that one of the previous "philosophy" statements made about such an amp would be that it would not purport to offer anything unusual or magical.

                            But in light of what seems to be a plethora of exaggeratedly "hot" volume controls on amplifiers in the market, with a concomitant reduction in usefulness, is this not an opportunity for meaningful differentiation?


                            • #15
                              Simple problem, simple cure?


                              Many thanks for highlighting this subject and explaining how a correctly specified systems volume control range should operate.

                              I suffer from lack of adjustment, my system being really quite decently loud at 11pm, though I mainly listen at 9 or 10pm on the dial, I certainly never venture to 12 onwards.

                              You mention the need for people with this problem to solve it (I only use CD), could I ask please, would you advocate a simple inline attenuator (a few popular ones I have read up on advise a level drop of 10db) being all that is needed to cure the problem?