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"This Harbeth User Group (HUG) is the Manufacturer's own managed forum dedicated to natural sound, realisable by controlling the confounding variables between tthe microphone and the listeners' ears.

For example, the design of and interaction between the hifi amplifier and its speaker load can and potentially will alter the sound balance of what you hear. To reproduce the sounds captured by the recording microphones, as Harbeth speakers are designed to do, you would naturally select system components (sources, electronics, cables and so on) that do not color the sound before it reaches the speakers.

Identifying components for their system neutrality should, logically, start with the interpretation and analysis of their technical, objective performance, as any and every deviation from a measurably flat frequency response at any point along the serial chain from microphone to ear is very likely to cause the total system to have an audible sonic personality. That includes the contribution of the listening room itself.

HUG specialises in making complex technical matters simple to understand, aiding the identification of audio components likely to maintain a faithful relationship between the recorded sound and the sound you hear. With our heritage of natural sound, HUG cannot be really be expected to guide in the selection, approval, endorsement or even discussion of equipment that is intend to introduce a significantly personalised sound to the audio signal chain. 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 electronics offered there. There is no on-line substitute for that time investment in a dealer's showroom.

If you desire to intentionally tune your system sound to your personal taste, please consider carefully how much you should rely upon the subjective opinions of strangers. Their hearing acuity and taste will be different to yours, as will be their motives and budget, their listening distance, listening loudness and listening room treatment, not necessarily leading to appropriate equipment selection and listening satisfaction for you.

Alternatively, if faithfully reproducing the sound intended by the composer, score, conductor and musicians over your speakers is your audio dream, then understanding something of the issues likely to fulfill that objective is what this forum has been helping with since 2006. Welcome!"

Jan. 2018
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Power Conditioner Myth busted?

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  • Power Conditioner Myth busted?

    Many of us agree the best time to listen to your Harbeth is late at night. No scientific explanation has been offered so far except for those you can find in power conditioners brochures, whitepapers and etc etc which suggests that RFI and EMI pollution of your power supply causes the sound quality to be affected.

    However, new study suggests our ears do have an inbuilt amplifier which controls the sensitivity of our ears to adapt to the environment noise. At night when the environment is much quieter our ears sensitivity peaked to hear softer sound. This may explain why music sounds better during late night listening.

    You can read about the Stanford University School of Medicine research here.


  • #2
    Your link doesn't work, but I believe what you are talking about is the well know masking effect (see here). Basically - if there is any background noise at all, it will hide music softer than it. Louder instruments will hide softer instrument as well. This is the basis for MP3 and Dolby Digital compression, by pruning away those part of the music that are 'masked'.

    Power Conditioner is another topic altogether. It is pure myth. The power supply of the amplifier/CD player and whatnot is already a power conditioner. The main power supply is of 50/60 Hz - and there is always a narrow band pass filter to allow only the mains frequency to pass through.

    I do not believe an external power conditioner will add anything to a well designed equipment. I am willing to hear if anybody has any measurements to substantiate any counter arguments though.

    A power stabilizer is the first piece of audiophile equipment that I was persuaded into buying by the great conviction of the salesperson. It is now working as a very expensive lightening protector. The rating of the stabilizer was 1kVA - it may only able to deliver 700VA realistically. If anything at all it will only serve to limit the dynamic response of my amplifier.

    Anyway it got me started into investigating the audiophile believe system - and the many claims that were parroted with great convictions.


    • #3
      I am not sure why but I just couldn't insert the link. Try again here. Also attached herewith the PDF version.


      p.s. The attachment file named as such for MY filing and record keeping. It is not the actual file name.


      • #4
        I use to think the same thing Yeencn, but I now disagree with you 100%. I've tried several "cheaper" power conditioners that were indeed expensive lightening protection. But I had been using a PS Audio P300 in my main audio system on the preamp and CD player for over a year when I decided it was a waste of money that I could put to better use. So, a friend wanted to try it, I let him take it for a couple weeks to audition, I called him after 5 days and asked him to return it and to tell him I did not want to sell it. I missed it badly, I did not enjoy listening to my system as much and the sound was noticeably different.
        I don't have measurements, I only have my ears. I no longer think that a good conditioner is a waste of money.


        • #5
          There may be some truth to both positions. All power conditioning are not the same, and the saying, "you get what you pay for" probably applies.I have been using Furman PC's for many years. My A/B comparisons tell me that the sound is improved, particularly in terms of dynamics and quieting. The Shunyata approach of filtering rather than regenerating may work better with dedicated mains. Certainly the benefits of power conditioning are subtle, and pale in comparrison to a speaker upgrade.


          • #6
            Saftely testing conditioners ...

            I PAT (electrical safety) tested an IEC cable last week (video here) using our certified PAT test machine and it failed although it seems to work perfectly and there is no problem with the three conductors end to end. The cable included a 'surge protector' and it seems that this protection device proves a permanent leakage path from live/neutral to ground that takes the insulation leakage outside the safety standard. The test box does not know and does not make any allowance for the anti-surge drain circuitry inside the cable - it just senses a leakage path.

            So, whilst not personally a believer in power conditioning/surges here in the UK with a well behaved spike-free supply, it could well be true that there are real measurable differences between the supply delivered to your equipment directly or via a conditioner/spike eliminator. This automatic tester will not proceed along the full test routine for this cable because it fails the basic safety test. Strictly speaking, I should discard it.

            Serious point: how confident are you about the electrical safety of your system? Has it ever been checked by a qualified person?
            Alan A. Shaw
            Designer, owner
            Harbeth Audio UK


            • #7
              Originally posted by jdinco View Post
              ...I missed it badly, I did not enjoy listening to my system as much and the sound was noticeably different...
              There is some more other unknown variables here: your relationship with that friend? The amount of money you can get from him? Do you really need that amount of money? Do you think he will pay now?
              apart from joking, it's almost impossible for me to say good-bye to any of my electronic equipments, even if I know consciously it's useless anymore. My unconscious (Freud) mind finds a reason to keep it easily which seems really rational.

              On the other hand, is it possible that everybody all round the world is away from radio frequency interference or electrical-noise pollution? Is'nt it possible that there is at least one county or village (or an old building) which hasn't got a clean power line that even a well designed equipment can't cope with, so it may be possible for someone to enjoy seeing Power Conditioner really works out?


              • #8
                Artificial noise in modern environment?

                I first post this article for some discussion to find out why night time listening offers more enjoyment than during the day. In my humble experience using two different kind of power conditioner (one of them is the so called balanced power supply) I am unable to find any discernible difference in my system.

                Having said that, I have often observed during a blackout at night in my dense but very quiet neighborhood, there is something different about the environment. Such as the birds chirping appears to be clearer. As if a veil has been lifted.

                There's definitely a drop in the noise level, but I am unable to pin point what it was because generally my area is quiet, no traffic or other man made noise.

                I have even tried to do my own experiment by shutting my main supply to the house and see if the sound was generated within my house, but it seems it is in the environment associated with electricity supply.

                Anyone else experienced this? Just a note, I never experience similar effect when I was staying in a rural area where I grew up, but I wasn't conscious about such things then.



                • #9
                  Have I experienced this? Yes... if I understood what you mean correctly.

                  I hear better at night, and also when I dimmed out the lights in a room. And also I close my eyes for a second as a reflex when I hear a instanteneous noise (or voice) to hear better because my brain sends almost all energy to hearing system (favouritism of hearing over seeing). Ion channels in my ear (as your link says); and the "MOC (medial olivocochlear) reflex" and "MEM (middle-ear muscle) reflexes" (which are activated by broadband noise) cause all. And also alcoholic beverages diminishes my hearing as well.

                  When I remove those factors no matter how, I hear everything better, clearer...

                  Lots of things may also affect those factors externally:
                  variation of particles in the air, density of air, electromagnetic waves ; and removed noise of the all electrical equipments etc. when we turn of the commutator of the main fuse in our house.


                  • #10
                    Definitely, late night listening is a moment of pleasure. It gets better if fans and airconditioning is switched off and will improve further if fewer cars with those silly noisy exhaust pipe is kept off the road... Noise pollution..


                    • #11
                      Have any of you looked into balanced power? Seems to make sense conceptually and is probably the only kind of conditioning I'd be willing to try.


                      • #12
                        Could you elaborate on 'balanced power' equipment? other than conditioning, what else does it do..


                        • #13
                          Originally posted by coredump View Post
                          Could you elaborate on 'balanced power' equipment? other than conditioning, what else does it do..
                          Pulled this from an FAQ on balanced power:

                          "In a balanced power system, the voltages on the system's two output terminals are 180 degrees out of phase to each other with respect to ground. The system reference (ground) originates at the output center tap of an AC isolation transformer. In other words, the system's grounding reference (zero position) is located at the system's mean voltage differential or zero crossing point of the AC sinewave. This is a far more effective way to establish a reference potential for an AC system. The center tap is then grounded to Earth for electrical safety and for referencing shields.

                          There is never any voltage or current present on the ground reference in a balanced power system. Transient voltages and reactive currents which normally would appear on the neutral and ground wires are also out of phase and likewise, sum to zero at the ground reference thereby canceling out AC hum and noise.

                          A balanced AC Power system works the same way as a balanced audio circuit but with a higher amplitude. Both balanced audio and balanced AC incorporate phase cancellation or common mode rejection to eliminate noise."

                          That sort of explains the essence of it, there are differing opinions on implementation. Some advocate the use of 240v (2x 120v) and a step-down transformer rather than what's explained above.


                          • #14
                            In essence, the balanced power method is utilizing a step-down transformer, i.e., 120V (2x 60V). In a traditional Delta-Wye configuration iron-core transformer, the output between the phases is not equal to 240V, but 208 volts. If phasing differences are to account for the reduction in reactive current reduction, then theoritically, the phase relationship of the two 60VAC sources would also be reduced, to 103 volts. Utilization of the toroidal core more or less defeats the "low" voltage output by using a dual-wound configuration of two 60VAC secondaries, which share a common ground. The same could be done for mains power of 240 VAC, but the power system designed around the delivered 3-phase 208VAC system in use in the US would need re-design. Modifying your equipment in your home at point of use would seem the likely path to take, then be self confident in your more efficient and cleaner power grid. Always pay fair attention to proper grounding of all equipment, as when you mix the intended design with a modification, dastardly things can happen.


                            • #15
                              I use a Balanced Power line conditioner in my system, and feel that it has made a considerable improvement. As a journeyman electrician, the concept behind balanced A/C made sense to me; much more so than parallel capacitors, huge "chokes", Bybee purifiers, or skin effect devices. First, by virture of using a transformer, you get isolation from the line and protection from (most) spikes and surges. Secondly, by shifting the ground to the center point of the secondary, you get a 180* phase shift which ensures that common mode noise will sum to zero at this point. Another benefit is that, by virtue of equal and opposite voltages, cables energized by balanced power do not radiate an electrical field. Problems associated with DC offset and triplen harmonics are also dealt with effectively by balanced power.

                              In researching balanced conditioners, I found that high quality units from Equi=Tech and BPT are quite expensive. As an audiophile as well as a music lover, I don't like to make sacrifices in terms of quality. I am, however, willing to exchange the Nth degree of "fit and finish" for a substantial savings. With this in mind, and some competence in working with electrical systems, I decided to make my own unit. I used a high quality toroidal transformer, POCC internal wiring, and audio grade receptacles. Although perhaps not as visually attractive as the commercially available products, I believe my unit to be the equal of these products in terms of function and performance. There is a wealth of information available online for anyone interested in undertaking such a project.

                              I wanted to make a few comments related to the above post. While I agree with most of what pete is saying, I don't understand how phase differences or reactive current would presuppose a 103V output from a balanced line conditioner. In the US, a Wye connected 3 Phase secondary does yield 208V between the phases and 120V phase to ground (or neutral). The phases are 120* out of phase with regard to eachother. Most residential services are single phase 240V supplied from a utility transformer. The center tap is grounded and 120V is available between either line and ground. In appartments or dwellings supplied from a 3 phase service, you have 208V between lines and 120V to ground for lighting and utilization loads. The most practical way to obtain balanced power is with a 1:1 wound isolation transformer with a 60-0-60V secondary. It is not necessary, or adviseable, to step voltage down (or up) in order to get balanced A/C. It makes no difference whether you're deriving power from a single or 3 phase service: 120V on the primary and 60-0-60V (120V) on the secondary are the only requirements. I apologize if I've misunderstood your post, pete.