HELIUS DESIGNS: in conversation with Howard Popeck – part two

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Geoffrey ….. When it comes to listening to what you've designed, do you worry that you can find yourself liking something which is actually wrong? How do you keep yourself on track?

In the context of tonearms it’s difficult to imagine what I could do to make it sound ‘wrong’. This part of the system is passive – although it doesn’t generate an audio signal in its own right; the idea is to prevent it from contributing something of its own personality and mask the music. As you lift the veils of colouration, it’s difficult to imagine how the sound could be described as ‘wrong’.

Turntables are slightly different in that speeding them up a semitone makes the music sound snappier, more ‘dynamic’; slowing them down can make them sound ‘richer’. So, yes, it is conceivable that some disks might sound better. Though briefly amusing, if you know it’s wrong, you don’t enjoy it for long and anyway, other disks will sound awful.

Okay, so what about speakers?

Ah, well ..... these are a completely different animal - especially 3-way systems were you have two drivers trying to reproduce the same piece of music simultaneously. This requires the engineer to make decisions on tonal qualities that greatly affect what the audiophile hears.

For instance …..?

For instance, if you believe that overlap should be minimal, then traditionally, you might opt for a Butterworth filter – but this leads to greater phase incoherence than ( say ) the Bessel network which permits more musical overlap but less phase shift.

In this sense, the engineer is working with a flawed technology and has to make ‘value judgments’ as to what he thinks sounds best. Unfortunately, it’s all too easy to create a product that demonstrates more apparent detail in the music, or projects a more forward/dynamic musical image – doing so in a way that the product will still pass conventional measurement tests.

Do you care to expand on this?

Okay. Have you ever wondered why it is that all loudspeaker spec. sheets look much the same – and yet sound so dramatically different?

Yes and, err, how and why?

The short answer is the published measurements that you ( the audiophile ) see, tell you very little about what how a product will sound.

Okay, yes, that's generally appreciated and so what I'd like to know is how do you keep yourself on track?

To start with, I’ve always adhered to a strict set of listening criteria. Firstly, I don’t judge a system on the basis of electronically generated music. As much as I love the likes of Vangelis, Jean Michel-Jarre, Kraftwerk or OMD – their music is unsuitable for critical evaluation.

A decent hi-fi should allow you to hear the difference between an Amati or Stradivarius – or a Bosendorfer and Steinway. So I connect myself with live music. One of my son’s is an outstanding musician, and I come from a family of singers – indeed, I occasionally perform myself.

It keeps me in touch with ‘the real thing.’ By regularly listening to real violins, guitars and pianos, I have a good idea of what they should like.

Which in practical design implementation means what?

When evaluating a design, I keep on track by using the widest possible range of music – Indian Sitar, Greek Bouzouki, Gregorian chant, Pink Floyd, Led Zep, Katie Melua, Johnny Cash –and yes, even Nana Mouskouri ( don’t laugh, she has a very pure voice). The theme here, if you haven’t already guessed, is that I use very simple, virtuoso performances with complex harmonics.

Overproduced or over-processed music is out because you learn nothing from it. I love the Moody Blues, but their recordings might put them in the league of the Muddy Blues – when preparing a product for manufacture, you can’t judge its performance on the basis of badly flawed recordings.

Thank you Geoff

END

http://heliusdesigns.co.uk/

To be continued

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