Acoustics Matters #1

Living-room listening to what conductors and musicians like to hear

by

Brian Maskell, Ambience Systems, New Zealand

Darwin may well have argued that once upon a time our species necessarily evolved with a highly-tuned ability to listen, most intently, to a spherical soundscape that might contain bird and animal sounds that could indicate that a leopard predator was stalking us at a certain distance and relative angle - and, of course, the vice versa use of the same ability if our species was stalking a prey.

I have often wondered whether males predominate in the intense-listening world of HiFi because there is some latent gene-driven desire to hone survival and hunting skills.

It is amazing how a jungle canopy contains and reflects animal and wind sounds to create a very efficient and useful ambience that is well-employed by the species in occupation.

Capturing indirect sounds

So, why is it that so many recording engineers seem to think that their task is to close-mic musical instruments in order to capture, exclusively, the direct sound being made – presumably on the assumption that they can fiddle with knobs post-recording to ‘balance’ a soundscape between instruments while also adding later a ‘unified’ level of reverberation (i.e. reverberation dissociated from the unique spectrum of frequencies reflected by the nature of the particular acoustic of the venue)? 

Arguably, such an approach constructs ‘omelette-like’ recordings that sideline the talents of the conductor as well as the inter-active musicianship of the performing team – thus the omelette produced has little association with the professional eggs that were used or the additional acoustical finger-print magic of the performing venue.

Thank the gods therefore that there are otherwise very talented recording engineers and recording companies (quite a few exciting boutique operations in Scandinavia, it seems) chasing outstanding recording venues with close-to-ideal acoustic parameters where minimalist microphone techniques can capture the optimum energies between an ensemble - direct soundscape and a reflected soundscape – sans multiple channels and fiddle-knobs!

Indirect (reflected) sound energies vary very significantly with the frequency of the original sound because of the dimensions and textures involved in a venue’s acoustic structure. Hence, each venue has a unique acoustic finger-print.

Musicians rely to a significant extent upon ‘tuning-in’ to reflected sounds from their ensemble fellow players so as to make and adjust their individual contributions to a unified ‘texture’ of sound. 

Such unifying ‘texture’ of an ensemble’s sound is a major ingredient in the degree of magic that can be delivered to a listener (or, of course, a minimalist microphone array capturing a recording).   

However, it is certain that much of the subtlety of such reflected sounds will have very low energies when arriving at a minimalist microphone array. However, that is where the enlightened recording engineers’ craft of selecting very sensitive microphones that can also handle high-energy direct transients without significant distortion comes into play.

There are some fantastic recordings available – but they can be very difficult to find and obtain.

Reproducing magical recordings

Because of a strong passion for performing music (piano and organ) and also for enjoying recorded music I have faced a life-time challenge of researching and thinking about the key reproduction physics that were limiting delivery of the magic into my living room that my addiction required in order to be satisfied.

[On reflection, that is probably why my early career embraced leading-edge materials sciences and advanced electronic systems.]

Facing retirement as a consulting strategist about five years ago, I decided that there were sufficient advances in materials and transducer technologies to ‘have a go’ at marrying three novel acoustic principles in an endeavour to reproduce – with a very high level of acoustic efficiency and detail - the sound textures and ambience signatures that I knew were available in some my most-outstanding recordings.

I had only very modest expectations that I might be marginally successful: I had a lot of experience of systems built around the physics of wave theories not behaving in practice according to those theories - and usually therefore needing a lot of tweaking!

But on the day of ‘switch-on’ of the assembled system (about five years ago), I was very surprised that there were powerful signs of magic – despite utilising a 20-year-old top-end Class A amplifier and myriad mixtures of interconnects between the contributing bits in the rest of  my aged system.

I had a wide 15 feet stable stereo image that could be enjoyed anywhere at the back of a living room; I had ‘textures’ to sounds that were captivating – but could likely be much improved; transients were slightly shocking; and the ambience magic captured by the high-efficiency of the electro-acoustic approach employed was firmly in place – but was likely dulled by an under-performing old amplifier and its associated external entrails.    

Thus began a now five-year journey to optimise what might be described as - 

a primarily indirect system (i.e. transducers do not point at listeners);

a system that employs acoustic phenomena that achieve very high acoustic efficiency when transforming input currents (necessary for reproducing low-energy detail); 

‘under-worked’ transducers that have minimal excursions thus avoiding mechanical damping effects that blur quiet detail; and

a system that can reproduce accurate and high-energy bass down to 16Hz.

The pre-production system has just been completed – with some latter-stage necessary support from Perreaux.

Ambience Speaker System

Electronics - clinical simplicity

Technically, I knew that it was possible to do away with most of the separate bits of kit that had entangled my audio system with entrails of very costly but dubious inter-connects.

From Canada, the Bryston integrated amplifier (in particular) took my strong fancy because it had exactly the calibre of technical specification that I knew would enable me to carry out the final tuning of my acoustic system reliably and get the best sound out of it. The advent of that Bryston amplifier and its offer of containing a top-end DAC was another persuasive factor. 

I was determined to keep interconnects strictly in the digital domain if at all possible. I wanted to avoid analogue-related capacitor and inductor effects stuffing up facets of the frequency spectrum and the integrity of phasing – particularly of low-level (ambience) signal material.

But then I learnt that the Perreaux company here in New Zealand had more or less coincidently developed a similar configuration available in its flagship 250i product. 

After studying the 250i technical specification, it was plain that I needed to contact Perreaux managing director Marty (Martin van Rooyen) to clarify a few details.

Days later – just prior to Christmas 2013 - a 250i to my specification arrived; it was quickly built into the rest of my system.

Marriage in heaven

Then the magical sounds really burst into my living room. High specification heroin had at last arrived for a deprived music drug addict!

A need for some further intensive ‘re-shaping’ and bedding-in between the three acoustic systems that I had employed became apparent with the 250i additional disclosures: that has been completed using a selection of outstanding recordings. 

I could now listen to a chamber group as though I was again playing in it [e.g. reference recording Sibeliusworks for violin and orchestra ; Peka Kuuisisto (violin and conductor) with the Tapiola Sinfonietta on Ondine ODE 1074-5 ].

At last, I could listen to a large organ and experience the ambience and ‘feel’ the ‘quiet’ power that so excited me when I was playing (in my youth) at a console of a large instrument (my bass system uses organ-pipe maths to chase non-resonant frequencies down to 16Hz). [e.g. reference recording Mussorgsky: Pictures at an Exhibition and Stravinsky: Three Dances from Petrouchka played by Jean Guillou at the organ of Tonhalle, Zurich on Dorian DOR- 90117]. 

{Be careful if you obtain and play this recording on your system – the recording-capture technology that it employs renders such an intensity of low-frequency information that it is quite likely to damage many systems unless strict caution is exercised.}

The 250i also transformed three-dimensional imaging – the sense of depth in the sound-stage. One of my reference recordings for that factor is a recording made in Cologne Cathedral by Motette MOT 50814 – a venue in which components of the massive organ are at a considerable distance from one another in three dimensions plus (on this recording) the added dimension of the Cathedral’s choir.

When listening to a recording of a 12-year-old Aled Jones singing on Virgin VIP 107 (sleeve title Pie Jesu), the texture of the reproduced sound rendered a musician and physician friend of mine to tears. The subtlety of musical expression and diction on this recording is a master-class for any aspiring singer (I used to be a boy chorister – necessary to get much cheaper organ lessons!).

A market for the Ambience system? 

A very satisfying measure of personal success with the evolution of my Ambience system poses some big questions as to whether or not there are music drug addicts of my variety in numbers sufficient to warrant consideration of taking the design to market. 

Shahinian did that with some success – despite the cost of his system in the market-place.

Female-sensitive features of my system are that the imaging mid- and high-frequency units are best (acoustically) wall-mounted at about standing eye height for an adult – well clear of children’s fingers and vacuum-cleaning hazards. Stereo bass cabinets ‘float’ on slippery sledges so that, although they have the appearance of wine cabinets and are seemingly (weight-wise) well-furnished with bottles, they do slip easily on carpets – and they can be positioned on any wall in the vague vicinity of the wall-mounted units (they ‘fire’ Northwards).     

Getting top performance out of the new acoustic system does require some fastidious attention to input gear. Of likely main importance is a low-error-reading CD player (Cyrus X series perhaps or a similar calibre CD spinner) and perhaps an integrated amplifier that has specs that approach the Bryston and Perreaux 250i.

Identifying outstanding acoustic recordings

If any of you have read this far and know about specific and outstanding bench-mark acoustic recordings I would be grateful if you could contact me with your suggestions – sdf1@clear.net.nz. Your other related commentary would also be appreciated.

Brian MaskellBrian Maskell

Brian studied piano from the age of 4 – eventually taking lessons in the Matthay piano-playing technique from one of the pupils of that great master of tone, detail and technique based on ergonomic principles. As a boy chorister he learned at Canterbury Cathedral voice-production techniques that enable a single solo voice to fill a large venue. At age 11 his legs were long enough to commence his organ studies. 

The very powerful sound of larger instruments and plus the superb choral acoustics that he experienced when he sang in Canterbury Cathedral began his lifetime quest for faithful reproduction of the detail of reflected as well as direct sounds: that quest underpinned and sustained his passion for understanding and mastering the complex physics of recorded sound.

Training in electronics led to involvement with development of advanced military control systems. That led to a period as Technical Editor of a leading journal specialising in complex electronic systems and new materials technologies – and an enduring interest in biophysics, ergonomics and human learning.

 

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