We had Rega’s local distributor (Synergy) provide a demo to the Melbourne Audio
Club. The session went extremely smoothly, Philip Sawyer was the "MC" from
Synergy. He gave us a run down on Cambridge Audio, Rega and Creek products. Rega was
pitched in the middle of these two in price/performance terms.
I had a particular interest in the Rega product line-up. The morsels of info about the
company itself were interesting. Rega have about 60-staff, putting them in a similar
bracket (size-wise at least) to H.J.Leak prior to the Rank takeover in 1969 (as Editor, I
have the right to make everything Leak-centric!). The Chief Design Engineer behind the
Rega products is Terry Bateman. We heard the Planet series CD player, the Mira amp (60W)
and the Jura speakers. This adds up to about A$5000. I was probably tagged as a
trouble-maker by Philip Sawyer, because I’d asked him during his demo if the Mira had
a balance control (which it lacks). This is of course in-keeping with the minimalist
marketing approach, although I would find a Balance control useful.
The DACs that Rega use in there CD players were mentioned (from Scotland, and 24 bit if
I remember correctly). The Rega amp featured a multi-turn volume control for precise
control.
I really liked the Jura speakers. Not that one can pass ultimate judgement from demos
in public-halls. But the clear, precise (and not-subdued) treble from them is something
that suits my taste. Later we heard the EPOS speakers, but I think the memory of the Rega
speakers had my preference on the night.
(I apologise for not covering the Cambridge or Creek products in this report)
Stephen Spicer
Less is More with Amplifiers:
The purpose of Hi-Fi is to bring music into your home. While it can produce an
acceptable substitute, our present 2 channel stereo, or for that matter multi channel
surround sound systems, fail spectacularly to produce a believable image of real-live
sound, and we don’t really know why. Our test regimes, based on sine and square wave
testing, do not stress the equipment in the way a music signal does, nor do they show up
distortions to which our hearing is sensitive. We see equipment of greater and greater
complexity and cost offered to the enthusiast which fails because it does not address the
fundamental failings of the 2 (or 5.1) channel stereo system.
It fails in three major areas
(1) The distortions generated by microphones and speakers are much greater than those
generated by the electronics,
(2) It fails because there is no test which represents the simplest MUSIC signal, nor
is there any attempt to test the whole system.
(3) Because we don’t really know what they are, our tests do not show up
distortions to which our hearing is sensitive.
There is no point in testing each individual component of the system with an inadequate
test signal regime, while ignoring the performance of the complete audio chain. From these
points of view, and even though the performance of the electronics is so much better than
the mechanical devices at the beginning and end of the chain, LESS IS MORE, the amplifier
is as good as it needs to be, despite the regular appearance of super amp reviews.
John Drew
Less is More with Microphones:
The weakest link in the audio chain is the recording. I will concentrate on unamplified
music, from the viewpoint of someone who attends these concerts. These include
soloists, folk groups, jazz bands, and orchestras. Hi-fi is about the realistic
reproduction of an original performance. This is not meant as a criticism of "popular
music", which uses amplification as a necessary part of performance, and is not
recorded with this end in mind.
I am going to support the minimalist microphone approach as patented by Alan Blumlein
in 1933. This system uses just two directional microphones placed one above the other.
This produces "intensity stereo", with no phase differences, and the image
position on playback is exact. It also gives the most accurate balance between direct and
reverberant sound. The musical balance is controlled by the performers, and not
post-production people.
Spaced omni-directional microphones is another minimalist approach. This is a time
based system where image location is mainly determined by the first arrival signal,
sometimes referred to as the "Haas precedence effect". A frequent criticism of
this method is that is produces inconsistent results, and "phasey" sound.
The multi-mike system in the extreme case, uses one or more microphones for each group
of instruments. These will be put down on a 24 track recorder, and mixed to stereo (or
surround) at a later time. It is nothing more than panned mono, and the balance and image
position are set by the post-production team. Close miking does not pick up any
reverberation, and this will be added artificially.
Recordings are often done by a combination of the above, a Blumlein pair being
supplemented by "spot" microphones. This is the most common method of recording
classical music.
An important point (rarely mentioned) is that the sound of any instrument or voice
miked at close range, contains more treble energy than when miked at a sensible distance.
This is due to the transmission characteristic of air, and is probably why many commercial
recordings sound "up-front", or even harsh. Why multi-mike in the first place?
For a start it can save money, as the performers can be sent home earlier, and the mixdown
done later by a couple of people. Also the sound of recordings can be more easily
manipulated (by equalisation etc.) to sound impressive or "larger than life",
and therefore sell more. This works because few record buyers regularly hear live
unamplified music.
Although I believe the Blumlein system sounds the most natural, I have to admit that
all of my current recordings sound pretty good. They have been carefully selected, and
hundreds discarded in the process. Not many would have been done in the purely Blumlein
method.
Doug Tipping
A Philosophical Approach:
If Less is More, then less of less is better, and less of more is also better. And even
less of less, and also even less of more are even better still. We have a convergence when
the changes come to a halt when there is no longer less or more because they have become
the same. We have reached an average position where Enough is Enough.
Of course, .Enough. depends on who is talking; it is a personal preference. We may
differ, and indeed we do.
So what are my preferences? Its seems to me that NOT knowing where I am on the less to
more curve is a poor condition to be in, so my preference is to measure as much as
possible. The data provides me with a guide as to what to try to reach Enough. The
ultimate Enough is determined by my ears.
As time passes, we learn more and the equipment for both playing and measuring
improves. So Enough changes, and I change the system where it is justified and with
measured effect to make it Better.
In my experience the progression to Better includes using more complex equipment, the
usual result of an engineering approach. Good, extended range performance requires
matching up components with complementary benefits. There is a kind of Gain Bandwidth
product limitation on simple devices, which shows up as being good in one area at the
expense of being limited somewhere else. You need multiple devices working together to
achieve Enough performance. Just Enough of them.
An Example:
A common Less is Better argument is that minimalist valve Amps are Better.
Notice, though, that Horn loading leads to low dispersion (A low radiating angle) and a
low frequency cutoff. This gives Horns a characteristic sound. Is that Hi Fi?
Very light cones can be good in the mid range, but they also need Horn loading or a
woofer to be added, so that the low frequencies can catch up. Like the Lowthers. These
Less complex systems can work well, within their limits. Especially on music which is Less
demanding - a single voice and just one or two instruments played at a moderate but
realistic level can be very pleasant. This is Enough for some people.
Others prefer loud and complex music - symphonies, operas, rock and home theatre.
Simple systems cant cut it. They are not Enough.
So I have a Tri-Amped system. A dedicated woofer with a powerful Amp, the lowest
distortion midrange I can manage with wide dispersion, and the smoothest and most extended
top end, also with wide dispersion. This is a More system but it is just Enough for me.
Mostly.... It clearly needs updating again....
Jim Menadue
| February 2002 |
|
AudioCentric 300B by Scott Thomson |
Several people in the club have been following Scott’s steady progress in
developing his 300B amplifiers via the various DIY and other home meetings. So it was
great to see Scott with the finished products in their anodized blue splendour at the GM
in February. Beautifully finished Scott!
Scott has described the amplifier design topology and specifications elsewhere in this
issue, so I will not attempt to repeat these here (besides the fact I know scant
information on them apart from the fact it utilizes an inter-stage transformer, ECC99
driver and 300B output ñ obviously!). However listening tests I have heard at Matt’s
show there is real synergy with high efficiency speakers and a musicality and power that
belie their decidedly measly 8W on offer.
The system assembled included Matt’s Lewis Muratori’s solid state
pre-amplifier, Rotel CDP 971 (modified with 6V output), and Lewis large floor-standing
speakers using premium drivers (Audax and Focal). The craftsmanship of his products is
always a visual delight also. The interconnects and bi-wired speaker cable were Silver
Stealth design utilizing high purity solid core silver in a closely coupled geometry with
Teflon dielectric. The bass grip, transparency and extension these have given Matt’s
system have been a welcome improvement. Custom lengths and now kit-sets are available.
True to form, the system displayed the attributes many of us have heard at Matt’s
home. A great variety of music, compiled by Matt, Scott and Kendrick was demonstrated
showing the many fine virtues of the system. Bass control was no problem (room
notwithstanding) despite the 8W, and the punch and drive also made it clear this was no
old world sounding 300B of yesteryear. There was no difficulty in driving the high
capacitance (but low characteristic impedance) Silver Stealth speaker cables. If you like
the pipe and slippers sound, then this is not the 300B for you. Words like dynamic, airy,
engaging and musical would be more to the point. In fact at least in my opinion, it was
one of the better demonstrations I’ve heard at the GM since joining some years back.
Clearly I am biased though!
My only reservation of the design is its low sensitivity. Few CDP or DACs will put out
such a large signal (6V) as the amp ideally requires without modification. Improved
sensitivity could be designed in (perhaps switch-able), but at the expense of using more
tubes most likely, with some reduction in transparency in theory. Scott might like to
consider what can be done for those without the inclination to DIY their CDPs in the
future.
Overall another most enjoyable night ensued. It’s always great to see members
develop their ideas into commercial realities. Thanks to Scott and Matt for providing
their equipment for the demonstration. It should be noted Scott is offering a 10% discount
for a limited time on the Audiocentrics and has some stock ready to ship now. Choices with
various tube types or even tube-less amps are available. Scott also murmured other
products, including a SACD player are in the pipe-line. Call Scott for more information or
visit www.thomsonaudiodesign.com. The Audiocentrics could be your future.
Kendrick Pavey
| January 2002 |
|
Wally's Horns |
At the January General Meeting, club members were treated to a relaxed, evening
listening to recent developments in horn loudspeakers by Wally R. The speaker concerned
has been christened "The Full Monty" by Wally.
For those who are not familiar with Wally, you should realise that he has a, keen, dry
sense of humour, extensive but sometimes understated technical, knowledge, and of course a
love of music and entertainment. With this in, mind, it is easy to see why the evening
with Wally was so different. Wally's, main aim was to present his speakers for people to
listen too in a, non-technical and relaxed manner, along with some dry humour and,
entertainment. This is indeed what Wally achieved. If you were there on the, night you
will know exactly what I mean.
Wally's speakers are based on a 4-inch full-range driver made by Fostex (the,
FE108sigma, rated at 15 Watts). To obtain sufficient low-frequency output, the rear of the
driver is coupled to a horn. The overall, frequency balance of the system was dependant on
how close to on-axis one could be seated in the hall. Off-axis, I found the results a
little dull for, my liking, but later when I moved on-axis to one driver, the treble was,
clear and well-projected (which I like).
Other people have commented at various times that these horns don't sound, like horns.
And indeed this aspect created a lot of interest on the night. I, think that this virtue
is one of the more intriguing aspects of Wally's, design.
Wally has also been quite successful in selling these speakers (including, to club
members). Prices are $1500 for the Fostex 127 driver, and $1600 for, the Fostex 108
driver.. In addition, various other drive units can be used, with the design, as has been
done by Wally in the past.
Wally's amplifier also generated some interest - a Beam Echo "Avantic" using,
ECL82 valves. It sounded very fine, and looked stunning, with quite, attractive
retro-styling that everyone seems to crave for. Wally's speaker, were well styled too, and
it was easy to see the attention to detail that, Wally had put into finishing his
cabinets.
I'd would like to thank Wally for his entertaining evening. I think that, once everyone
had latched on to the idea the Wally "is just a lucky, guesser", people settled
down and enjoyed hearing his horn system.
Stephen Spicer
