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November 2003 Editorial

It's the room, stupid!!!

Author: Geoff Husband
Published: October, 2003

Just had an interesting experience. I've finally finished building our new conservatory, a beautiful concoction of glass and local chestnut, and at 7.7 x 3.5m a large extra room on the house. Even though my knees were still sore after two days laying and grouting quarry tiles I still found the energy to install a hifi system!

Well I suppose it showed a certain obsession, but one of the problems (honest) of a reviewers life is having wonderful stuff lying around in boxes either waiting to be collected, awaiting review or just put away because something was not needed. So with some glee (and to my wife's annoyance) I spent a happy afternoon setting up a very fine second system. In the end on my Clearaudio rack went a fully loaded Linn LP12 and Linto. Amplification was courtesy of the Son of Pharao valve amp and speakers were my own IPL S3TL transmission lines. In all around 15000e of serious kit. With great expectations I dropped the needle into my latest fave bit of the black stuff - the White Stripes 'Elephant'.

Really, really dreadfull. The most horrible ghastly noise. Now I know what you're thinking, "the idiot's built a glass room, lined it with hard tiles and is complaining because he's got a horrible 'glassy' sound."

Well wrong actually. It's a common misconception that rooms with hard surfaces will sound 'hard'. My conservatory is as bad as you could wish, the walls which aren't glass, are solid granite - even the inner doors are glass. The result is a boomy woolly mess, no midrange clarity, no treble at all, swamped detail - AM radio is better and I'd have preferred my wife's ghetto blaster in my normal listening room.

So what is going on? A lot has been written about ideal room dimensions, but the fabric of a room is even more important.

Here's why..

When a speaker produces sound waves, i.e. music, those soundwaves propogate out toward our ears and there the waves are decoded into what we actually 'hear'. The snag is that sound doesn't just propagate towards the listener, but to other parts of the room. When these 'rogue' waves hit an object they are absorbed and/or reflected. In a 'hard' room most of the sound energy will be reflected and this will also find its way to your ears after one or more 'bounces'. Because sound travels slowly these reflections will arrive after a greater delay than direct sound from the speaker and if the reflecting surface is very efficient (like glass) then these delayed waves will be nearly as loud as the direct sound. So the result is a muddle - blurred leading edges, no imaging and as for ambience! - this is not hi-fi.

But things get worse. Different frequencies react in a different way. Low frequencies are omnidirectional, that is they spread in concentric circles from the driver - so a huge amount of bass energy is reflected. (you can see what's coming...) The further up the frequency range you go the more directional the sound waves become, to the point where high treble comes direct from the tweeter. So whilst the bass is summed by a whole load of reflections (all delayed and out of phase), mid range less so and treble hardly at all. The result is a bass, lower mid increase and a shy treble.

In total the result is "The result is a boomy woolly mess, no midrange clarity, no treble at all, swamped detail" - exactly what I'd got.

And I'm afraid I'm limited as to what I can do about it. You see my conservatory is a beautiful place (you can tell I'm proud) and I love it's sparse wicker furniture and bare stone walls. I could damp the room with curtains, heavy furniture, thick carpets, bookshelves and all the standard 'fixes' to stop reflections but it would fundamentally change the very nature of the room and that's not a compromise I am prepared (or allowed...) to make. I swapped my speaker cables to a single run of CAT 5 which tightened things up a little, small speakers with little bass output would help. I guess an edgier TT and amp would help but only for tonal balance, ditto fancy room correction systems, but nothing will bring back the phase coherence and detail that is so much part of hi-fi. The fact is that as far as hi-fi is concerned the room is a lost cause, spending 100,000e on super-fi would make not a jot of difference.

And this is one of the unfortunate truths about hi-fi, unless you are prepared to make major changes in your living area, some rooms will never support hi-fi sound. I'm lucky as for hi-fi I go back to my main room which is as dead as a doornail and so sounds bright and detailed and glassy (but classy :-). But for some of you the only answer is headphones...

© Copyright 2003 Geoff Husband - www.tnt-audio.com

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