12/05/2010 Tweaking your system.

Tagged under cables, equipment isolation, Hi-Fi, tweaks
Posted by Len | 1 Comment

The following article first appeared in the June edition of T3.

This is a subject that can create a lot comment, both positive and negative. We would be very interested in any feedback that you may have, and more importantly, we would welcome any tweaks which have improved the performance of your system. Particularly if those upgrades can be preformed inexpensively.

‘Super Sounds:
by Len Wallis

There have been a couple of serious distractions to traditional Hi-Fi over the last decade or so. Home Theatre has taken the emphasis off sound quality and moved it to vision. MP3, and in particular the advent of the Apple iPod, also took the emphasis from performance, instead highlighting both content and convenience. However there are changes afoot.

We are witnessing a trend back to performance, and with that a renewed interest in what we loosely term Hi-Fi. The difference now is that many consumers have discovered widely varying genres of music, and a great number of people, and that number is increasing, are listening to true digital sources. While the iPod may have been derided as the enemy of Hi-Fi for years (due to its poor musical quality) it has exposed most of us to music that we would never have previously considered. Along the way it has also become the ‘go-to’ source for that music. The irony is that this poor cousin to the CD has suddenly blossomed into a musical source that can, and does on many occasions, provide a level of performance that was unachievable on CD. More on this another day.

Now that you have discovered the joy of listening to music again (and by this I mean listening to the music, not the equipment), and you have shelled out your hard earned dollars on a good system, how do you get the most out of it? It may surprise you to learn that some very simple, and in most cases inexpensive, tweaks to your system can have a greater impact to the performance of that system than your choice of the components themselves.

While I am aware that in the real world not everything below will be possible or practical, you should follow as many of the following suggestions as you can.

The Room
The greatest impact on the performance of your system is going to be the room itself. Unfortunately it may also be the one factor that you have least control over. Room dimensions, construction and furnishings can make or break the enjoyment you will receive from a system, and generally the more cubic the room (i.e. the room is as wide as it is long as it is high) the worse the system will sound.
However don’t despair, there are some simple tricks that you can do to improve many rooms (partners willing!). One of the more common complaints today is that the system sounds too bright in the room – brought about by today’s trend towards glass, unadorned walls and stone or timber flooring. The trick here is to introduce some softer elements, rugs on the floor, paintings on the wall, etc.
The main problem with overly-bright rooms is reflections, and it is the reflection points that you need to work on. Imagine that the walls are mirrored – the spot where you would see the speakers in the mirrors on the wall is where you need some type of reflective or absorptive device. This can be as simple as a painting (no glass), a bookcase (better still), or you can go all out and purchase acoustic panels which are designed exactly for this purpose. Don’t forget the floors – the same rule applies, place a rug or mat at the reflective point.
On the other hand the sound may be dull and lifeless – if this is the case it is possible that the room is over furnished. Removing some of the clutter may just give that spark you are looking for.
Make sure that there are no items in the room which can rattle or resonate, particularly with lower bass notes. This can include light fittings, air conditioning ducts, ornaments and racks.

Equipment position
Positioning the system. Speaker positioning in particular can, and will, have a huge impact on the system’s performance. There are a number of rules that should be followed when positioning your speakers in your room.
Ø Don’t place the speakers against the side walls, and definitely not in the corners of the room – room corners effectively horn-load the bass and will cause it to boom. If possible also move the speakers off the wall, particularly if the speakers have a rear port.
Ø If you are using bookshelf speakers on stands the speakers should sit so that the tweeters are at ear height, and both speakers should be at the same height.
Ø Now comes the tricky bit. Your listening position should be at the peak of an isosceles triangle, i.e. you should be sitting equidistant from both speakers, and they should be situated as far from you as they are from each other. Ensure that you don’t sit too close to the back wall; make sure that you are at least half a metre away.
Initially face both speakers so that they are facing straight ahead, directly at the wall behind you. Have a listen to a piece of music you know well – you should find that you can hear music coming from both speakers, with a ‘hole’ in the music between the speakers. Now slowly angle the speakers in towards your listening position. You will find that as you do this the ‘hole’ in the middle is gradually filled with music. The system should eventually snap into place where you can no longer hear where the speakers are situated, but you are presented with a three dimensional musical image which extends not only from the outside of the left speaker to the outside of the right speaker, but which also has front to back depth. Each instrument and musician should have their own space, and you should be able to ‘hear’ the air around the performers. (Some recordings have done a better job of recording this spatial information than others, the better the disc the better the effect.) In most cases this will occur when the speakers are facing directly at, or slightly in front of, the listener.
Ø For the seriously keen there is a mathematical way of determining where you should initially position your speakers relative to the rear and side walls. Firstly multiply the height of the room by 0.618. This will determine the distance from the rear wall to the centre of the woofer. Then multiply the width of the room by 0.276 and this will give the distance that the centre of the woofer should be from the side walls. Then continue on as above.

One of the simplest and most effective improvements you can make to your system is to ensure that your speakers are solidly mounted. There are two important aspects of speaker performance that you need to know. The first is that they work by pushing air forward – if the speaker is unstable the force of pushing air forward can also cause it to slightly rock backwards, lessening the impact of the note. Secondly the speaker can store energy generated by the movement of the speaker cones. Energy from the floor, speaker stands, etc. can also be transferred to the speaker box. This energy has the effect of muddying the sound and blurring the musical image (the system’s ability to pinpoint the relative positions of musicians, etc.)
If you are using speaker stands ensure that they are firmly anchored to the ground, and this is usually done by spikes. These have a two-fold effect. The very small contact areas make the stands very rigid, plus they tend to draw energy away from the speaker boxes. Many stands can be sand or lead-shot filled, adding mass, and again dissipating energy. Most quality speaker stands will also have spikes between the top plate and the speaker.
Outside of the room acoustics, which many of us have little control over, and the correct positioning of speakers, I have found that ensuring your speakers are correctly and solidly mounted is the most effective single upgrade that you can do to your system. It is not expensive, and you will be surprised by the results.

Isolation of equipment.
Vibration has a detrimental effect on the performance of electronics. This effect varies from component to component, but valve and source components (CD players, turntables etc) are particularly susceptible, it is a lesser problem for amplifiers, tuners etc. For this reason avoid placing speakers on the same shelf as your electronics, the vibrations from the speakers will travel through the shelf and into your electronics. There are a large number of isolation platforms which will have a positive impact on the performance of susceptible equipment, and there are numerous specialty rack systems which do a good job of housing your system as well as isolating the system from vibration.
One very inexpensive suggestion is to cut some squash balls in half and use these as isolation supports – basic, but works well.
Whenever possible avoid stacking components on top of each other. Not only will this increase the chance of unwanted vibration being transferred between components, it also inhibits heat dissipation.
While we are on this subject, ensure that the components in your system have plenty of room to breathe. As the use of micro-processors in audio continues to grow, so does the heat that they generate, and the more susceptible they become to the effects of that heat. Ensure that there is plenty of space around your equipment.

The Cable Guy.
Without doubt the most contentious issue in audio is cable. Cables have different inductance, resistance and capacitance characteristics, and it is the relationship of these three characteristics that cause cables to vary in sound. These differences occur due to the variations in construction and the materials used. Yet there are many who can prove to you, mathematically, that cable cannot make a difference. At the same time most people who have been open minded enough to try better than the supplied zip-wire that comes with most systems have been more than impressed.
It is generally conceded that 10% of your audio budget should be spent on the speaker and interconnect cables.
Cable lengths should be kept as short as possible, and all connectors should be secure and tight. If you are particularly fastidious you may occasionally give the connectors a clean. Isopropyl alcohol (from you local chemist) will do the trick. If you are using bare wire instead of banana plugs on your speaker cables check occasionally for oxidation, and if necessary cut off the exposed section and strip back a new section. Never roll any excess cable into a coil; this introduces inductance, which will degrade your system’s performance.
Also ensure that you have isolated all power cables from the speaker and interconnect cables.

Super Cable:
Another hotly debated area of contention is the power supply. The power delivered to your system is anything but ‘clean’, and this will have an impact on the quality of your system. Noise is introduced into your power supply from numerous areas, both inside and outside of your home, and everything that we hear (and see) in our Hi-Fi (and A/V) systems starts out as raw AC power from the wall. The addition of a mains filter can have a very positive impact on your system.
If you are particularly keen you may also entertain the idea of taking a dedicated AC power feed from your electrical switch box to the system point. It is a safe bet that the existing power points in your room will also be servicing a number of other areas, and every power point along the way can contribute to the noise on the line.

The good wine.
Finally, if your equipment is new its sound performance will improve over time anyway. Most pieces of equipment that you own, in particular amplification and speakers, need to ‘burn-in’ with use. How long this takes will depend on the piece, for example Focal Utopia speakers need a minimum of 100 hours of use until they reach their peak performance. Most products also perform a little better when they are warm, this is particularly true of valve equipment.
If you are intending to have a quiet night in listening to music, turn the system on an hour or so prior.’

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