EDITORIAL
04
I
can recall a bygone era
when specifications were
meaningful. They were
poured over by enthusiasts,
and heavily scrutinised by
reviewers. Then along came
Home Theatre and any
semblance of honest comparison
went the way of the dinosaur.
For example, checking the specs on
the Australian website for Yamaha’s
RX-A550 receiver shows that it is
rated at 60 watts/channel, with two
channels driven, or 115 watts/channel
if only driving one channel. But this is
a Home Theatre receiver — surely it
will be driven with five speakers? Plus
this figure is into a 6-ohm load, while
traditionally power ratings are into
8-ohm loads, which will be lower.
But then re-checking, this time on
the US Yamaha site, the same receiver
is rated at 80 watts with two channels
driven – this time into 8 ohms, which
(in theory at least) should be less than
the 6-ohm rating given above.
Interestingly enough, in the reviews
that I have been able to dig up so far
on this receiver, none of them actually
measured the power ratings. One did,
however, compare it to a 110-watt
rated alternative, and commented that
they thought the Yamaha sounded
‘the least stressed when we ramped
up the volume’ – something we would
usually associate with a more powerful
receiver. Incidentally, the Yamaha
reviewed very well!
This criticism is by no means
aimed at Yamaha. All manufacturers
appear to play the same game, andYamaha is more honest than most.
All the Yamaha ratings above are
‘measured’ at 20Hz to 20kHz, which
is the universally accepted standard.
However I have found some receivers
where the rating is given at 40Hz
to 20kHz, which will look more
impressive, but is unrealistic in a
real-world situation, particularly
when using the system to play music.
Worse still, many manufacturers
specify their power ratings at
1kHz with one channel running,
a completely useless figure.
The problem arises from the
fact that when running one or two
channels a certain demand is put on
the power transformer in the unit.
As the number of channels being
used increases, this demand is
increased, the power available for
the two front channels is reduced,
reducing in turn the power output.
Of great importance is the quality
of the transformer itself. While
researching this I came across an
article where an A/V receiver specified
at 88 watts/channel (one channel
driven) on test delivered 28 watts/
channel (x 5) when used under real-life
conditions. In the same article another
product rated at 155 watts/channel
(again one-channel driven) delivered
111 watts/channel under real-life
conditions, a much closer finding.
So where does this leave the
consumer? Unfortunately up the
proverbial creek. All you can rely
on is your ears, and the advice
from your dealer – make sure it is
a reputable one!FROM THE DESK OF LEN
Aventage update
Yamaha have expanded their Aventage
range of A/V receivers. Traditionally
this series started with the model ‘7’,
currently the RX-A750. While this
will only be a limited release we are
currently carrying the new 5.1 RX-A550
receiver, selling for $799.
Despite being Yamaha’s ‘budget’
Aventage offering it still has most of
the features in its larger siblings, such
as their wireless Multiroom system,
MusicCast. It also has built-in Wi-Fi,
Bluetooth, AirPlay, and is Spotify ready.
Yamaha’s other addition to the
Aventage range is the RX-A710. This
is a 7.1 A/V receiver, with its primary
difference from the rest of the range
being that it is a slimline model. There
are many situations where space is a
consideration, and at 111mm high the
‘710 will be an ideal solution in many
situations. The RX-A710 sells for $1,199.