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AUDIO REVIEW JOURNAL £12.50 Vol3/No3 JULY-SEPTEMBER 2009
REVIEWED THIS ISSUE:
LINN LP12 RADIKAL
LINN KEEL FOR ARO
PMC IB2i
DCS PAGANINI TRANSPORT
DCS PAGANINI DAC
DCS PUCCINI U-CLOCK
AESTHETIX CALYPSO
BRYSTON BP26
ROKSAN PLATINUM PRE-AMP
CHORD QBD76
REHDEKO RK175
ROGERS LS3/5A (NEW)
CRYSTAL BRIDGE
XTZ ROOM ANALYSER
SUPERCHARGING THE SONDEK
Linn’s LP12 SE enhancements
VINYL (THERE ARE NO) RULES!
Are audiophile LP re-releases any good?
A MINEFIELD IN MINIATURE
The bi-wiring conundrum
UP THE DCS STAIRCASE
Getting to grips with the state of the digital art
A STUDIO MONITOR FOR THE HOME?
PMC’s IB2i gets the full treatment
DELICIOUS DAC
Chord Electronics’ gorgeous QBD76
SMOKE & MIRRORS
The recording techniques that won Jim Anderson
nine Grammys
THREE SERIOUS PRE-AMPS
Classy pre-amps from Aesthetix, Bryston and Roksan
MUSIC & MORE
HIFICRITIC JULY | AUGUST | SEPTEMBER 2009 29

A Studio Monitor
For the Home?
THE EDITOR DECIDES THAT ONE OF HIS PERSONAL FAVOURITES
SHOULD GET THE FULL CRITICAL COLLOMS TREATMENT
This IB2i speaker is built by PMC – the
UK’s Professional Monitor Company,
which self evidently makes studio monitors
alongside many other speaker designs of different
shapes, sizes and purposes, all of which feature
the company’s ATL (advanced transmission line)
bass loading. Is there a difference between a studio
monitor and a domestic hi-fi loudspeaker? In
theory, no: both should be accurate, informative,
have low coloration, provide focused stereo images
and recover lots of detail.
Our review model was the attractively finished,
real walnut veneered IB2i, a broad equivalent to
the Pro-Audio IB2S version. Although the two
have much in common, they’re not identical. The
IB2S has an alternative tweeter, is finished in a
durable matt textured ‘Neo Black’ and incorporates
three alternative treble control settings (for film
soundtrack balancing). It also has an active drive
option, which is only available with PMC’s larger
domestic models.
Our review IB2i is a large no bullshit standmount,
with the broad performance profile of a
classic Spendor BC3 or SA100 three-way monitor.
But it’s actually rather more compact than those
examples, and more obviously comparable to ATC’s
slightly smaller port-loaded SCM50SL, a threeway
monitor that’s available in several domestic
and Pro versions (active or passive, stand-mount or
floorstanding), and is its most obvious commercial
competition.
PMC also makes a floorstanding equivalent of the
IB2i called the EB1i. Its slightly longer transmission
line promises marginally deeper bass, but the lower
price reflects the fact that it’s fitted with a less costly,
bought-in midrange driver. But it does still beg the
question: “why should you want the stand-mount
version?”. (Paul Messenger also alluded to this in his
comparative review in vol. 3 no1.)
Like PM, I recognise that stand mount designs
deliver a certain degree of free articulation in the
lower midrange and bass. This I suspect is down
to the fact that the staggered spacing to the three
nearest room boundaries may produce a smoother
in-room response than the essentially two available
with a floorstander, though I appreciate that that is
something of a simplification in the complex real
world of coupled acoustics. Whatever, the IB2i
combines the advantages of a tolerably sized stand
mount with the high power handling capabilities of a
medium studio monitor.
A 2.4m transmission line is folded within its
modest dimensions, and this is terminated by a
large rectangular front port – clearly way too big to
function as an ordinary bass reflex port. Technically,
the line presents a complex acoustic back load to
the bass driver, and the designer has considerable
freedom to fine tune the quantity and placing of
damping and absorption components, such as
foam blocks and wadding. These help control the
relative level of upper and lower bass contribution
from the line, and are designed to suppress the
natural harmonic resonances of what is, acoustically
speaking, a multi-resonance tuned pipe.
Since the sound from the back of a piston driver is
naturally out of phase with that from the front, and
can potentially cancel main signal, the other purpose
of an extended line is to delay and thus phase shift
the lowest frequencies so they are sufficiently phase
reversed to make a positive contribution to the
overall output when they emerge from that large
aperture, rather than cancel negatively. In fact the
loading is closer to a quarter-wave inverter than a
reflex, so a tighter transient response can be expected.
Furthermore, those secondary resonances often need
careful adjustment so as not to add coloration to the
low frequency band.
Clearly there are questions about delay arising
from the transit time down the line and whether
the resulting bass will have significant, audible
group delay. There is more to the perception of
good bass timing than group delay alone and the
designer has a big say in how any speaker sounds,
having the opportunity to fine tune and balance
a number of design parameters. The proof will be
found in the listening.
I remember that classic transmission lines often
went deep but sounded slow. This one, even from
early auditioning, sounds deep and fast. And I know
how dynamic it can also be, since I heard it driving
an audience of 90 persons in a large and reflective
lecture hall for the London AES, with nary a squeak
of bass limiting or audible distortion. And it was
LOUD. In fact under domestic conditions I reckon
30 HIFICRITIC JULY | AUGUST | SEPTEMBER 2009

◆ REVIEW
MARTIN COLLOMS
more distortion will be generated in the ears than
from this loudspeaker.
The styling is classic box speaker, nicely finished
in walnut. Some visitors said it looked oldfashioned,
which didn’t bother me, but it’s clear that many
consider narrower, faceted or curvaceous speakers
more elegant. The three terminal pairs are not
special, and their brass linking rods were poor,
in particular impeding the use of spade cable
terminations. I replaced these links with properly
done up solid copper wire and enjoyed an immediate
improvement in mid and treble clarity. The grille was
also weak, the frame thin enough to be warped by
the fabric tension and barely holding on to its few
studs. Measurement (1.2dB loss plus +/-2dB ripple
in the upper range) and listening (loss of clarity and
dynamics) showed that the grille introduced real
impairment, so I simply left it off.
Technology
The drivers are centrally mounted in a vertical
line, with little consideration given to enclosure
diffraction, nor any pretensions to time alignment.
Will this detract from performance? Well, it
depends. Time alignment has audible but secondary
benefits, and I consider it should not be the goal
if it compromises primary characteristics. In the
IB2i those fundamentals are fully addressed; in the
cruel world of the professional, failure to perform is
rewarded by the sound of the studio door slamming
after you.
Bass comes from a 10in (250mm) driver with a
planar 190mm diaphragm of carbon fibre skins on
a Nomex honeycomb core. This is driven by a high
power handling 75mm voice coil, with the desirable
if rare combination of a short coil in a long gap. The
moving parts are stabilised via a double spider and
a stiff half-roll surround. A planar bass unit has the
advantage of smoothly continuing the front panel
profile, whereas conventional cone drivers suffer from
some coupled resonance coloration and diffraction
due to their conical cavity. If the bass unit mounting
looks a bit weak with just four small socket head
bolts, that is only for the metal trim; underneath
it is securely fixed by eight massive bolts. Looking
inside, I felt that although the moderate spring-grip,
push-to-release connections to the bass unit were
handy for easy servicing and avoided soldering, high
retention spades or better still hard soldered joints
might sound better regardless of the inconvenience.
The midrange unit is PMC’s heroic 75mm softdome
driver with a custom doped fabric diaphragm
and very powerful coil and magnet assembly, capable
of very high sound levels at low distortion.
The product of cooperative design work with
SEAS the double back-loaded 27mm ‘Sonolex’
(doped fabric) soft dome tweeter is custom made for
PMC, and has ferrofluid cooling to increase dynamic
headroom.
The high order, nominally Linkwitz-Riley
crossovers have precision 24dB/octave slopes
at 380Hz and 3.8kHz, and driver pass-band
equalisation. A mixture of electrolytic and
polypropylene film capacitors are used alongside
ferrite-cored and air-cored inductors. These are
good quality components, but not so-called
‘audiophile’ grade.
HIFICRITIC JULY | AUGUST | SEPTEMBER 2009 31

◆ REVIEW
Sound Quality
A revealing and fundamentally accurate transducer,
the IB2i reads sources well. It needs quite a lot of
current, is best suited to amplifiers of 50W upwards,
and showed no sign of flagging when fed 400W. If
you want to hear that stomping, percussive, visceral
low frequency output, you need a stomping amplifier
to drive it.
I cannot speak for the PMC-distributed Brystons,
not having heard them for a while, but the generous
output current of Naim’s 80+80W SuperNait, had a
good go, while it sailed away on my reference 350W
and 40A peak Conrad Johnson Premier 350SA. Here
the peak current drawn by the IB2i is estimated at
nearly 30A max.
The sound is bold, muscular, lifelike, not quite
larger than life, but evidently high in contrast and
definition. Forget considerations of sweetness and
micro-focus; instead wonder at the studio grade
dynamics, the confident, even assertive drive that’s
able to deliver the entire musical content in the
programme.
If a speaker reflects a designer’s intention and
taste, then I hear his intention here as delivering the
audio message, and more importantly answering
the following questions: how a track is constructed;
how present are all the frequencies; what is the
programme tonal balance; is there any distortion;
is there unwanted low level noise; are the right
mikes connected; and how are they placed relative
to the instrument or performer? And not least, how
is the overall production balanced from track to
track? Answer these questions well, and you define a
truthful and informative loudspeaker.
Characteristically, familiar tracks replayed on the
IB2is sound rather like you always thought they were
meant to sound; how you imagine you would have
heard them played back in the studio.
The IB2i does this by first laying down a beat,
where bass, mid and treble are unmistakably dynamic
and propulsive. A drum kit sounds percussive, lively,
crisp; as it should. It backs the band; as it should.
Vocals come over with excellent clarity; particularly
clear enunciation is unmistakeably of quality
monitor standard. As a track begins you are clear
about the production, how many musicians, and
when they come in, how the track is built, and what
you think the producer intended.
The treble is crisp, detailed, just a tad ‘edgy’ at
times, but well in keeping with the sparkling, livesound
effect. Where an audiophile designer might
be tempted to smooth things over, PMC keeps
the energy going and makes sure that the overall
performance delivers the information the recording
engineer needs. Drum sounds are consistently
faithful: snare, rim, brushwork, all are vividly
reproduced, driving the rhythm forward.
Note that this is not a nearfield monitor,
compensated for proximity and/or for mixing desk
boundary effects. Instead it is designed for free-field
use on stands, and such is its inherent accuracy that
it will fit easily into larger domestic environments
while still maintaining a truthful inherent balance.
The big bass is well matched to studios with some
bass absorption trap tailoring.
While the bass and treble are good, of which more
later, the midrange is undoubtedly the star, showing
subtlety, depth, excellent detail, and low coloration.
Yes there is just a hint of that characteristic ‘doped
soft dome’, almost ‘fibrous’ diaphragm sound, but
it is proportionately less objectionable than the
frequently ‘shouty’ cone drivers often employed in
this position. Indeed, it’s easily forgotten, and this
dome driver’s unfailing purity, openness, uniformity,
and dynamics are achieved with no squeak or
stridency. It joins up beautifully to the treble and
you could buy this speaker for the midrange alone,
and for its magic sound on vocals. It can make many
costly audiophile speakers sound a bit muffled.
The whole bass register, including driver and
line contributions, must be balanced against the
midrange. This has been done well. The bass is quite
tuneful, is punchy, almost percussive in its near live
quality, and is well extended to better than 25 Hz inroom.
The often difficult to tame line contributions
have been excellently blended with the overall
output.
It is unmistakeably lively but the icing on the
cake is its astonishing bass power capacity. This
combination of line and custom driver is clearly well
optimised, and delivers the power and dynamics
worthy of a 12in unit, so the bass end performs
well out of its size and class. The IB2i delivers a
muscular, authoritative and fundamentally accurate
sound, making many domestic speakers sound like
overpriced wimps.
Imaging shows good depth, particularly in the
midrange, although it doesn’t achieve the far depth
resolution found in more costly creations. Coloration
is low, but not vanishing so, yet the balance of
coloration, including some moderate contributions
from the enclosure, is somehow blended so that
one doesn’t really care, and discovers that it’s the
whole sound that really convinces. Thus piano is not
the most accurate, but is very clear, live sounding,
dynamic, and highly expressive. So which matters
more, subjective performance or some possibly more
sterile criterion for low coloration?
Just slightly lean in mid timbre, you might expect
it to jump forward on difficult material, eg Jan
32 HIFICRITIC JULY | AUGUST | SEPTEMBER 2009

◆ REVIEW
Gabarek on sax, but the mid is so classy that it sails
through even on this. Conversely, if the source is
rough, forced and compressed, it will be laid bare.
Most listeners will find it fast, informative and
dynamically expressive, particularly on ‘studio’
recordings with healthy reverb, such as Patricia
Barber’s Café Blue, on which it works very well
indeed. Conversely, older more subtle material,
such as Joni Mitchell’s Blue, shows some loss of low
level detail and the temporal coherence which helps
support the sense of timing. Here it does not match
the musical timing of a Naim SL-2 or indeed the
essentially time coherent Avalon Eidolon (though I
accept that the latter is many times more expensive).
A nearer competitor is the rather larger floorstanding
Wilson Audio Sophia 2, which resolves depth and
focuses very well, though it does cost forty per cent
more. A personal audition with familiar music will
help resolve issues such as these.
Lab Report
The type of studio monitor with horn-loaded mid
and treble can have efficiencies as high as or higher
than 96dB/W, and therefore need to be large to
deliver reasonably extended bass. With its direct
radiator mid and treble, the IB2i is not more efficient
than most domestic speakers of its type, and has only
average 85.5dB sensitivity for its 5ohms nominal
impedance. While generally 6ohms, the amplifier
load is a reactive (52 degrees) at 5ohms for 70Hz.
Furthermore, over the bass ‘power’ range 80-120Hz
the actual impedance is a low 3.6ohms. It also falls
to 5ohms in the upper treble. The effective port
resonance is confirmed at a low 30Hz. This is a
6ohm speaker, and if a valve amplifier is to be used
it should quite powerful with a good current delivery.
Examining the set of frequency responses, the bass
response is well extended to about 23 Hz -6dB and
is very healthy from 27Hz up, essentially free field,
if elevated about 3dB on the main range, and thus
suited to larger rooms with modest low frequency
gain. It is very smooth across the broad midband,
120Hz-8kHz, encompassing both crossover points,
with closely toleranced +/-2.5dB amplitude limits.
Taking note of the natural narrowing directivity
of the dome tweeter in the final octave, this latter
frequency band is designed to rise by about 2.5dB,
even at the optimal measured angle (10 degrees
lateral, on the midrange axis), and I had found that
the upper treble was subjectively presented a little
forward of the main image. Conversely the ‘room
sound’ was nicely open, whereas some other large,
flat front speakers can often sound dulled in the
upper frequency range.
At 15 degrees below axis it is great (black
trace, dip is due to floor reflection), but its above
axis response is notched by 15dB at 3.8kHz, so a
listening position near or a little below the designed
midrange axis is best, with the speakers slightly
toed out from the pure triangle formation. The
lateral off-axis responses are very good, smooth and
even, showing that good attention has been paid to
integration (right out to 60 degrees off-axis) and to
the fine power response which you hear voicing the
room acoustic.
Confirmation of the above, and of the rich
extended bass is given in the room averaged response.
Here up to 5dB of lower bass lift is present even
in my semi open-plan layout, but like PM I did
acclimatise to it to some degree. The rest of the curve
shows the fine balance and integration achieved for a
monitor based design.
I would rate this speaker at 400W music
programme power handling, which will provide very
decent in-room sound levels of 106dB and a bass
dynamic range that’s also sufficient for larger rooms.
I found it possible to apply really high sine wave
levels – 26V (85W) at 25Hz , 29V (105W) at 30Hz
and 35V (150W) at 40Hz – before overload, so the
bass driver and loading method is very capable.
Distortion was generally low, particularly in the
mid and treble, but that’s not to say the bass was
not good too. For 30 Hz, 96dB spl, second and
third harmonics were about 3%, below audibility.
At 120 Hz, 86dB, second was 0.1%, third still fine
at 0.15%. At a higher 96dB spl some rise was to be
expected, now second recorded 0.6%, but third still a
fine 0.15% (credit that fine motor). (For the record,
fourth and fifth harmonics were better than 0.06%.)
By 200Hz some increase was noted, but nothing to
cause concern, for example at 96dB second harmonic
was at 1%, third a very good 0.13%.
Moving on to that midrange unit, for 700Hz
and 86 dB spl I measured 0.033% second and
0.003% third, both superb results, and distortion
was still better than 0.1% total at 96dB spl, which
is pretty loud for sine wave drive. The tweeter also
was excellent, with distortion almost as low as that
remarkable midrange driver.
I used relative nearfield measurement to check
the crossovers and found the acoustic responses to be
well behaved at 380 Hz, approx 24dB/octave, and at
3.6kHz actually nearer 29dB/octave. The tweeter’s
good power handling is aided by the fact that its
frequency response is tailored to a massive 45dB
down by1kHz.
Stethoscope and accelerometer analysis confirmed
significant panel resonances in the midband, for
example at 260Hz, for the back and sides which
represent a significant radiating area. While multiple
HIFICRITIC JULY | AUGUST | SEPTEMBER 2009 33

HIFICRITIC
Awards
BEST BUY 2009
PMC IB2i, FB1i
RECOMMENDED 2009
PMC Fact-8, OB1i
Review System
Naim SuperNait, Conrad
Johnson 350SA, XTC 100
power amplifiers, XTC PRE-2,
Conrad Johnson ACT2-2, and
Audio Synthesis Passion preamplifiers,
Naim SuperLine
phono stage, Linn LP12/
Origin Live DC motor/Naim
ARO/Koetsu Urushi Sky Blue,
Naim CDS3, Marantz CD-7
players. Cables by vdH and
Transparent.
Comparison Speakers: Avalon
Eidolon Diamond, Quad
ESL63, 15ohm LS3/5a, Sonus
Faber Guarneri Homage,
Meridian DSP7200.
Contact:
Tel: 01582 405694
www.pmc-speakers.com
bracing is present from the folded line partitions, the
enclosure remains quite lively by modern standards.
There is some enclosure coloration but it’s handled in
such a way as not to be obtrusive .
This behaviour cannot be seen on the waterfall
energy decay display, since this primarily assesses
the axial sound output over a necessarily short,
resolution limiting time window. Here the essentially
uniform response can be seen in the top line of the
‘waterfall’, with good initial clearing, though with
some time differential then evident between mid and
treble, then some clutter shows, earlier than usual.
Anechoic measurement would be required to decode
this data properly. The decay responses themselves
are not particularly smooth and minor decay ‘ridges’
are also evident at about 18kHz and 11kHz.
Conclusions
I found the sound quality was highly consistent
over all classes of material. This speaker is even
tempered, always upbeat, well committed to musical
performances, and with very clean articulate vocals.
The upper end of the frequency range is slightly
lifted, which projects the treble somewhat. It has a
first rate, dynamic and detailed, broad midrange,
and a very powerful, rich and extended deep bass,
which is rather greater than you might guess from
the size. Coloration is moderate, nothing really to
object to but enough to make a piano sound less
freely resonant, to mildly impair far field image
transparency, and also the deep decay tails of
reverberant sounds associated with the subjective
sense of timing.
It’s not as sensitive as expected, at a just average
85.5dB/W, but the amplifier load is average in
difficulty, and it’s kinder to amplifiers than many
modern three-way designs. It delivers a well
engineered, no nonsense standard of all round
quality, making no concessions to styling or other
artificial constructs or abstractions. It just gets on
with the job of acoustically marrying the fine drive
units and playing the music well, providing plenty of
information about its complex content and how well
it was recorded.
Well suited to larger rooms, and perhaps also
those with some low frequency loss, the IB2i has a
very big heart and will play very loud with very low
distortion when asked. Should we really ask for any
more at this price? Recommended.
PMC IB2i: Load Impedance and Phase (dashed)
PMC IB2i: Energy Decay Waterfall Display
PMC IB2i: Frequency Responses
Make ______________________________________________________________________
PMC
Model ______________________________________________________________________
IB2i
Finishes ______________________________________________________________________
Satin real wood veneer
Size ______________________________________________________________________
(wxhxd)
33x74x46.5cm
Weight ______________________________________________________________________
41kg
Type
three driver, three-way, ATL loaded
______________________________________________________________________
(1/4 wave termination plus line)
Sensitivity ______________________________________________________________________
for 2.83V
85.5dB
Amplifier ______________________________________________________________________
loading
Average: 6ohms, reasonable phase angles
Frequency ______________________________________________________________________
response, axial
27Hz to 20kHz +/- 3dB, (listener axis) : excellent
Frequency ______________________________________________________________________
Response, off axis Excellent power response
Bass ______________________________________________________________________
extension
23Hz for -6dB
Max ______________________________________________________________________
Loudness (in room)
106dBA for a stereo pair
Power ______________________________________________________________________
rating
20 to 400W
Placement
Stand mounting, free space location
34 HIFICRITIC JULY | AUGUST | SEPTEMBER 2009