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A few hints for those of you
who would like to get the best out of your A/V system and have
an open mind (worshippers of What, Which or Whose HiFi Magazines
had better leave now)
Bi-Wiring, this'll upset any audiophiles who slipped
through my front page warning! For general home use, bi-wiring speakers offers
absolutely no benefit whatsoever except for doubling the thickness of the
speaker wire (which is why most people can hear an improvement). Those little
electrons don't magically split into various frequencies and follow the path to
the correct speaker (tweeter, woofer or whatever) so don't waste your time and
money.
Bi-wiring does work, however, when using separate
amplification for various drivers. This is used mainly in super top end home
systems using bi or tri amplification and in most professional sound
re-enforcement systems. The reason it works well there is because each amplifier
can be matched to the driver in terms of frequency and damping, it also reduces
cross harmonics since an external crossover circuit separates the various
frequency bands and points them to the matching amplifier/driver configuration.
Bottom line? for normal home systems, use better speaker wire, it'll give you
the same effect.
Speaker Cables - Ah, my pet subject. I guess
having formal qualifications in both metallurgy and electronics (albeit 30 years
ago) I can get a fairly good handle on how those nasty little electrons wizz
through cables from amplifier to speaker. Lets dispel some myths first -
-
Forget uni-directional speaker wire, the signal to the speaker
is alternating current and as such "vibrates" through the wire rather than
travel linearly along it. If a speaker wire has a directional arrow on it, ask
the salesman "why" and "how" it works.
-
Thin wires for high frequency's and thicker wire for the low's -
give me a break! The "skin effect", which is the name given to the phenomenon of
high frequency AC signals traveling only on the outer skin of the conductors,
only occurs to any significant effect in the megahertz region (just a tad higher
than the 20kHz of standard CD's or even 192kHz DVD-A/SACD/Whatnext Formats.
-
OFC or Oxygen Free Copper is a must. Well actually it is, but
the very nature of copper wire manufacture means that virtually ALL copper wire
is 99.9% + oxygen free, so the differences between different OFC's (99.9% or
99.9999%) is relatively moot.
I won't go into the why's and wherefores of single crystalline
structure wire, capacitance, inductance etc. except to say that an electrical engineer and audio specialist
far more qualified than I, one Jim Rowe, who for many years was editor of Radio,
TV and Hobbies held a double blind test using engineers and musicians whereby a
high quality set of speakers was set up with an amplifier using several sets of
speaker cables of about the same gauge. After several hours of listening and
switching cables, no listener could accurately say which cable sounded
better (or even different) from any other. You may go into a so-called
"audiophile" store and swear blind that the super duper, silver coated, multi
strand, variable thickness wire being demonstrated sounds better than the plain
Jane standard wire but you're the victim of psychoacoustics, in other words
you're being conned into spending way more money than needs be (not to mention
lining the pockets of the "audiophile" store - you ought to see the markup on
this stuff).
The long and short of all this is quite
simple - you need the wire to easily handle the current flow to the speakers,
commensurate with the output of the amplifier. Obviously, the longer the run of
wire, the thicker it needs to be so for those short runs (1 to 2 metres) don't
go overboard and pay more than $6.00 a metre. For runs 5 metres and above you'll
need to spend around $10.00 or more per metre. The exception is for surround
speakers in a 5.1 or 6.1 system where the speakers are designated as "small".
This is because all frequencies from around 85 Hz and below are sent to the LFE
channel and as such the current sent to those surround speakers is significantly
less since the lower bass frequencies are responsible for most of the energy
transmitted through the speaker wire. So for a good connection to your speakers,
count on spending around $6.00 to $10.00 per metre for your main speakers and
$2.00 to $6.00 per metre for surrounds. If Alan Audiophile tries to tell you
otherwise ask for a demonstration to justify the $20 per metre wire he's likely
to try to flog you - and make sure when you're listening, that both sets of
cables are heard at the same volume level (the louder sound always sounds
superior to the ear). Next week we'll talk about bi-wiring and really upset the
AW's.
Not so much of a Tweak but an observation - Many customers
come into the store sweating over which receiver or amplifier to incorporate
into a system - more so than the speaker set-up - wrong way around! They
speakers are responsible for around 75% of the total sound performance so the
time and effort should be spent determining which speakers are the best for your
particular needs. The receiver should lock itself into place depending on the
features required, technical spec's of the speakers and main intended use, for
example, in a similar price range Marantz may be better for music but Yamaha
with it's superior decoding chipset may be better for Home Theatre (although
this isn't always the case). Any good HiFi dealer should be able to suggest the
correct Amp/Receiver to match the chosen speakers, although you need to make
sure there is no hidden agenda with the suggestion (such as that dealer
importing the products recommended). If you need a reasonably honest opinion
just e-mail us and we'll give you a relatively unbiased answer (I say relatively
'cause there are some brands I just dislike regardless)
Furnishings - Ever wonder why, after purchasing HiFi from
an up market "Audiophile" store, the system never sounds quite as good at home?
Go back to the store and check their furnishings and dimensions. I'll bet
there's no parallel walls in the room (hence no standing waves and better bass),
I'll also bet that if you clap your hands in the room there'll be no "slap" echo
(high frequency bounce). The reason for this is that the furnishings will be
soft and hence absorb the higher frequencies. You can make the most of your
system at home by realizing what's happening to the sound as it bounces around
the room. If you have lots of glass windows, try for curtains rather than hard
blinds and make sure you have some form of soft floor covering. If you
have slate, tiles or polished wood, even a scatter rug in the centre of the room
will make an incredible difference to the sound. These sound absorbing soft
furnishings will ensure you get an intimate sound rather than the nasty echoing
that's so annoying. If you're building a dedicated sound room from scratch, do
what the pro's do and ensure there are no parallel walls (check out the inside
of your local movie theatre next time) this will give you the ultimate in room
acoustics. Finally, use a cotton bud to gently remove any wax lurking in your
ears (I find an extra 4kHz of top end after a good clean out).
Speaker Placement - Usually not a lot of
thought goes into where the speakers are placed and once plonked down, they very
rarely get moved. Speaker placement is critical and needs to be addressed to get
the most out of your system. To understand the basics of speaker placement it's
important to remember that the higher frequencies travel in a straight line,
much like a flashlight beam whereas the lower the frequency, the less
directional the sound until you get to the point where the sound is omni
directional (the point at which the wavelength is longer than the distance
between your ears - usually around 120 Hz). With these points in mind, it
becomes obvious that the tweeters in the speakers should be at ear height or at
least angled towards your ears to form an equilateral triangle, this will ensure
that the sound stage is reasonably stable. The distance of the speakers from the
wall will determine the quality of bass, as the lower frequencies are omni
directional, they will "creep" around the box and tend to cancel themselves out
to some degree as the speaker box moves further away from the wall, this will
"tighten" the bass although diminish it's impact. As the speaker box gets closer
to the wall, the bass will reflect off the wall and be re enforced, this tends
to give a stronger bass albeit "sloppier" or less controlled. The secret is to
move the box in and out from the wall until the best compromise is achieved.
With a sub / satellite system the distance from the wall is no longer a major
issue as most of the frequencies concerned are handled by the subwoofer. I may
come back to this subject in more detail at a later date but all this thinking
is giving me a headache so I'm going home for a bourbon and coke!
This weeks tweak involves cabling, regular readers
will know that I'm not a great fan of the smoke and mirrors tricks associated
with expensive interconnects, most dealers push them 'cause it's an easy sale
with plenty of profit. Good interconnects, however, are important and most
systems can benefit by upgrading from the crappy leads that come standard with
your DVD, CD or other source. As usual, some of the Pommie magazines go over the
top and suggest spending 10% of the system price on interconnects (Darwin was
correct in regards to isolationist inbreeding - that's why we came to Australia
to evolve the gene pool). I would generally look at spending 10% of the
SOURCE equipment on interconnects i.e. if your DVD was $1000 then you would
need to spend around $100 on cabling - that includes both audio (fibre optic or
digital co-ax) and video leads. In terms of video cabling, I wouldn't worry too
much on a standard TV set whether you have to use S-Video or Component cables,
there's not much between them and both are immensely superior to the standard
composite video cable. If your TV has progressive scan, then the Component cable
is preferable. For digital connections I prefer fibre optics, not because it
sounds any better (there's no great difference) but simply because it makes a
better connection. The cheap $20 fibre optics cables are OK but the $50 - $100
cables seem to offer more depth and definition - certainly worthwhile for better
systems. Remember also to keep your cables as short as possible, the longer the
cable, the more likely it is to pick up extraneous noise.
Subwoofer settings. It's a
difficult process trying to get a subwoofer to seamlessly integrate with the
main speakers especially when it comes to music reproduction. Most surround
sound receivers give the option of sending the bass information to the main
speakers, the subwoofer or both. I've found that, regardless of the size of the
main speakers, the best result is when the setting is on "both". In theory the
subwoofer can be placed anywhere in the room but for optimal music reproduction
I suggest the sub. be on the same wall as the main speakers and if it can't be
placed between the speakers, make sure that it is no further away from the
closest speaker than the distance between the speakers (trust me on this one).
As a rule of thumb for the initial set up, place the phase switch (if available)
at zero, the level to around 50% and the crossover to around 20% off the lowest
setting (don't worry about the figures on the label - they're wrong anyhow).
Tweak the settings from there, until it sounds good to your ears then leave it
alone.
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