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HUG - here for all audio enthusiasts

The Harbeth User Group is the primary channel for public communication with Harbeth's HQ. If you have a 'scientific mind' and are curious about how the ear works, how it can lead us to make the right - and wrong - audio equipment decisions, and about the technical ins and outs of audio equipment, how it's designed and what choices the designer makes, then the factual Science of Audio sub-forum area of HUG is your place. The objective methods of comparing audio equipment under controlled conditions has been thoroughly examined here on HUG and elsewhere and should be accessible to non-experts and able to be tried-out at home without deep technical knowledge. From a design perspective, today's award winning Harbeths could not have been designed any other way.

Alternatively, if you just like chatting about audio and subjectivity rules for you, then the Subjective Soundings area is you. If you are quite set in your subjectivity, then HUG is likely to be a bit too fact based for you, as many of the contributors have maximised their pleasure in home music reproduction by allowing their head to rule their heart. 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 only, although HUG is really not the best place to have these sort of purely subjective airings.

The Moderators' decision is final in all matters and Harbeth does not necessarily agree with the contents of any member contributions, especially in the Subjective Soundings area, and has no control over external content.

That's it! Enjoy!

{Updated Oct. 2017}
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Microphones - how do they response to the sound waves around them?

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  • Microphones - how do they response to the sound waves around them?

    Clearly, they generate an output. But how does that relate to the sound waves they sensed?
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  • #2
    We defined sound waves here. What humans call sound is nothing more or less than the consequence of a sound energy source - a loudspeaker, a voice, a bell, a bomb - rapidly raising and lowering the local atmospheric pressure in the vicinity of the source.

    The front end of the audio recording/reproduction chain requires that those local sound pressure variations are sensed. The sensor is called a microphone.

    Clearly, the moving parts of the sensing microphone must be of very low mass. The moving parts must be practically as featherlight as the wings of a butterfly. Only if they are extremely light weight could they be expected to detect the minute changes in air pressure caused by the sound source modulating the air around the microphone.

    If we disassemble a modern condenser (capacitor) microphone, we can identify the working parts, mechanical and electronic. The sound pressure around the microphone is detected by the diaphragm, typically about 25mm diameter, and far thinner than the thinnest paper. That gold-plated plastic diaphragm is clamped rigidly with a ring of tiny screws, and as you can imagine, the diaphragm is very stiff.

    Because the movement of the diaphragm in response to local sound pressure is tiny, millionths of a millimeter of movement, signal-boosting electronics are needed as close to the diaphragm as possible to minimise hiss and hum.

    See here:
    Click image for larger version  Name:	diaphragm.jpg Views:	1 Size:	173.6 KB ID:	74300
    Featherlight diaphragm inside microphone that senses the sound pressure around the microphone


    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

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