Some years back I saw a TV programme about the Turin Shroud – a holy relic believed by some to be the burial cloth used to wrap Jesus Christ after He was taken down from the Cross. The Shroud carries what is in effect a ‘negative’ image of Christ’s body, and only fully reveals itself when photographed and reversed. By increasing the contrast, the rather soft image on the Shroud starts to show an incredible amount of fine detail invisible to the eye.
For most of the time the Shroud is kept locked away in a special container. But every so often it’s taken out, unfolded, and hung so that people can view it. I was fascinated and intrigued when the TV programme mentioned that, in order to see the image clearly, you needed to stand a long way back. For most of us, the natural inclination would be to move closer in order to obtain a clearer view. But, as you do so, the image on the Shroud ‘disappears’.
Apparently, when you get right up close to the Shroud, there’s virtually no image at all. Only by viewing at a distance can the shape be discerned. Interestingly, this finds a parallel with archaeologists looking for old settlements or pathways – they have to fly high above the ground in a helicopter or aeroplane in order to see the outlines of long destroyed dwellings or roads.
Only from the air can such things can be discerned. On the ground, the changes are so subtle they’re missed completely. Yet ironically, the fine detail at ground level could not be more abundant; you can see every blade of grass – its exact colour and shape – not to mention tiny flowers and insects. The only thing you can’t see is the bigger picture – the broad outlines that suggest a larger reality.
What’s this got to do with Hi-Fi?
There’s a parallel with Hi-Fi. The closer you sit to your loudspeakers, the harder it is for the sound to cohere. This is especially true with loudspeakers that have several drive units. Each driver has a different phase and amplitude response; each has a different dispersion pattern. Only by sitting a certain distance away will this mish-mash gel together. Sit too close and you’ll be overwhelmed by detail at the expense of the larger picture.
That’s why it’s very important to experiment with speaker placement and listening position. Once, I installed a hi-fi system in a room, choosing what I felt was the ‘best’ place for the speakers. The sound was okay, but not as good as I’d have liked. Then, some months later, the owner rang to ask me to come over and move the equipment for her – where I’d put it did not suit her domestic arrangements.
When she showed me where she wanted the speakers placed, I shook my head and told her it wasn’t a good position. She said she accepted my misgivings, but that’s where they had to go. Result? The system sounded much much better! I was amazed – and so was she. Agreed, the sound didn’t image as well, and there was a much poorer soundstage with the new arrangement, but the music itself sounded much more cohesive and coherent – much more involving.
Some systems seem to give great insight into the music. Each individual note has colour and shape; each musical phrase has coherence and meaning. There’s a sense of forward thrust – of things moving inexorably towards a goal. Rhythmically, the music has swagger and timing, pace and attitude. Alternatively, it’s soothing a sensuous. It lives and breathes. It communicates.
This makes the listener feel part of an aural journey, and able to comprehend the route the music and performance are taking. The result is a sense of inevitability and rightness. Yet it’s often very difficult to say exactly why one system makes music and another doesn’t. Moreover, you can take a system that sounds magical in one particular location, and find it sounds completely unmagical when set up in another
This feeling of rightness may be hard to explain, but it’s immediately obvious when you encounter it. When you do, you experience music as the musicians themselves must’ve felt it at the moment of performance. At other times this coherence is missing. The sound quality may be terrific in hi-fi terms – loud, clean, and dynamic, with a wide-bandwidth – yet the music fails to make sense and engage the listener. It’s a collection of sounds rather than a living breathing performance.
Why this occurs is difficult to explain. It’s partly down to equipment, partly down to rooms, and partly down to the listener’s physical proximity to the speakers. It’s also tied in with the way many of us evaluate the changes we make to our hi-fi systems, and the criteria we use when deciding what’s better and what’s worse. Put simply, it’s easier to detect changes that increase fine detail compared to those that improve coherence. Here’s an example…
Why You Should Listen to Single Speaker Drive Units in Mono.
During the early 1980s I discovered the joy of evaluating changes and tweaks by listening to a single speaker drive unit in mono – say, just the tweeter on its own with the bass and midrange units switched off. Agreed, it all now seems deeply sad, but doing this made it possible to home in on specific areas – in this instance the top-end – in order to gain a clearer insight into how tweaks or a change of component or cable influenced a specific area of the sound.
For example, listening to just the bass driver allowed you to hear how clearly it reproduced the lower frequencies without help from the other drivers. I’d choose a disc with a strong but clear bass line, and see how easy it was to discern the pitches of the notes. Let’s suppose I was experimenting with taking the damping out of my speakers, or putting Deflex damping panels in place of the wadding. I’d modify one speaker, listen, then A/B compare it to the other.
If I heard a dull tuneless Thud Thud Thud from the unmodified speaker, and clearly discernable pitches, tonalities, and better dynamics from the modified one, I’d know the change had been worthwhile. I’d compare the two speakers – modified and unmodified – a few more times just to be sure, and then (assuming I liked the change) modify the other speaker. I’d then do a last quick A/B comparison to check that both speakers now sounded the same.
Why You Shouldn’t Listen to Single Speaker Drive Units in Mono.
When I listened to the speakers with all the drive units working once again, the improvement would be very apparent. Yet, useful as this approach was and is, I soon realised its limitations. Quite simply, it puts the emphasis on detail rather than the bigger picture. Of course, the big picture is made up of detail, and detail is very important. But, you can hugely increase the reproduction of fine detail without improving the overall coherence of the musical reproduction.
There’s another issue – and this a tricky one. Basically, there are two kinds of change. The first is straightforward – a bit like the example I gave regarding the removal of internal wadding from loudspeakers. What you see (or hear) is what you get. The second kind of change is much subtler and more elusive. This change behaves more as a catalyst – not seeming all that significant by itself, but having a profound almost disproportionate effect on other parts of the system.
It’s not the degree of change that’s important, or even the nature of the change; it’s the effect it has on the things around it that’s significant. Super tweeters are an excellent example. The one’s I use are Townshend’s Maximum Super Tweeters, and I have them adjusted for minimum output. They make a big difference. Yet, if I go up close to my main loudspeakers while the music plays, I can’t tell if the super tweeters are working. They seem to contribute nothing to the sound.
Are You Sure They’re Actually Working?
Let me run that past you again. Even if I put my ear right up to the front of the super tweeter and switch it on and off, I can’t hear any change. I’m not talking about a hearing change of quality, I’m saying I can’t tell if it’s working or not! The sound coming from the main speaker drive units effectively drowns-out whatever contribution the Super Tweeters seem to be making.
Yet, when I repeat the same experiment sitting in my listening seat, the difference with the super tweeters on and off is very big. You don’t have to sit there straining to hear it – it’s an immediately obvious difference. The Super Tweeters create greater depth and transparency, giving the music a more holographic three-dimensional quality. The sound is more coherent too. But why? Why is it that the effect can be heard at a distance but not close up?
Logically, you’d think that, if you can’t tell whether or not something’s working with your ear pressed to the front, it couldn’t possibly have any effect on the sound when heard at a distance. Because the other drive units are producing so much sound, the only way for the Super Tweeters to compete is for them to produce a fairly strong output too. However, such ideas are completely wrong. It’s actually the other way around.
In actual fact, the super tweeters produce their greatest influence on the overall sound when used at their minimum setting. If you increase their output, in the mistaken belief that the effect on imaging and coherence will increase, you find the opposite happens. It actually decreases. You’d think it would be t’other way around, but it isn’t! To create the biggest effect, the Super Tweeters need to be used very sparingly. I don’t know about you, but I find this very strange…
What’s even stranger is the way the super tweeters subjectively affect the lowest frequencies as much (or more) than they do the super-highs. Because we’re talking about super tweeters and extending the loudspeaker’s high frequency response beyond audibility, you’d expect any changes to concern things happening at the top end – sharper percussion transients; greater attack, and so on. While this does happen to a degree, there’s an unexpected twist.
With the super tweeters working, the bass generally grows firmer and tighter, with increased depth and better control. It’s uncanny – the bass sounds deeper as a result of using Super Tweeters! But why? If you switch off the main speakers and just listen to the miniscule contribution produced by the Super Tweeters on their own, it’s very difficult to understand how and why they have such a big effect. Bizarre!
Subwoofers Do More Than Produce Floor-Shaking Bass.
In much the same way, adding a subwoofer not only extends the low frequencies, it creates a more dimensional holographic soundstage and makes the treble sound smoother, sweeter, and more extended. The sound has added richness and depth. Try this experiment. Play a loud busy brash forward-sounding recording with lots of fast leading edges, and A/B compare the overall sound with and without super tweeters and subwoofers.
With both working, the music will sound more coherent and better sorted – paradoxically, less ‘loud’ despite being more powerful and dynamic. It gets worse. Logic would tell you that Subwoofers and Super Tweeters would only have an effect when the recording being played contained very low and high frequencies. That being so, if for instance you chose to play a recording of an instrument with no deep bass or extended highs, the Subs/STs would make no difference.
Wrong again! When I first added subwoofers to my system, I used to demonstrate the difference to friends using blockbuster recordings with massive deep bass. You know – large pipe organs, big bass drums, heavy synthesisers – the usual impressive demo stuff. The idea was to shake the floor and rattle the windows. But later I found something vastly more impressive – the slow movement of Vivaldi’s concerto for two Mandolins…
Look Ma, No Bass!
This movement consists of the two Mandolins playing a simple tune very quietly. Play this piece with just the subs on their own, and it’s impossible to tell if the music has started – the result is silence. Even going up close to the subs, you can hear nothing – except perhaps a slight low-level studio rumble. Yet when you put the whole system together and play the music, the subs make a very noticeable contribution to the sound.
The subs create a palpable ambience that gives the Mandolins a sense of being in a 3D space in a real acoustic. There’s a greater feeling of air around the instruments, and they have a sweeter more natural tonal quality. I have more than one recording of this Vivaldi concerto, incidentally, and interestingly it doesn’t seem to matter which one I choose – the end result is the same. If I switch off the subs, the soundstage collapses…
In exactly the same way, subtle modifications to a speaker’s crossover can profoundly alter the way it shapes the music – creating big differences that seem totally out of proportion to the degree of change made. Indeed, if you evaluated the change by playing just the speaker drive unit concerned on its own, you’d probably conclude that the change was so subtle as not to be worth bothering about. Yet the effect on the overall sound can be very significant.
For some reason, it’s important that the change being made is fairly subtle. Components like subwoofer and super tweeters only transform the sound when you use them sparingly. This applies with a vengeance to subwoofers. There’s a tendency when you first get a sub to play it too loudly so you’re always aware of its influence on the sound. For a few weeks your system sounds a bit like those overblown car stereos that have so much bass the car bodywork rattles…
Turn It Down…
Eventually, you turn the sub down a bit. And then a bit more. Eventually, you reach a point where the sub integrates seamlessly with the main speakers – so much so, you hardly realise it’s there. And then something magical happens; the sound is transformed. The improvement is far greater than the sum of the parts. The sub does not make its presence obvious, but nonetheless has a profound effect on the overall sound at all times.
It’s as though subs (and super tweeters) act as a catalyst on the rest of the hi-fi system, creating results that go far beyond its contribution. They don’t just entertain the bats with super-sonic highs, or beef up the lower frequencies and add weight to bass drums and organ pedals. They enhance recordings of music you’d think would not affected – like the Vivaldi recording of two mandolins playing quietly. Truly, the reproduction of sound is a subtle and complex business!This entry was posted in WRITERS and REVIEWERS and tagged Jimmy Hughes on .