Update
- The L.R. Baggs M1 Active
Following
their development of the Tri-ax pickup for Takamine, L.R. Baggs
now offer the M1 in active form, under their own brand and in
their signature cream and brown livery.
Like
the Tri-ax, the M1 Active features a finger tip adjustment volume
control and over 1,000 of playing time from an on-board 3V lithium
battery.
The
on-board electronics ensure a low output impedance for lowest
possible cable noise, lowest hum pickup and the ability to drive
almost any audio input with no loss of sound quality.
The L.R. Baggs M1
– Magnetic, passive, sound-hole mount, pickup for acoustic
guitar - Reviewed
A pioneer in acoustic
pickups and one of the leading companies in this field L.R. Baggs
started out making piezo under-saddle pickups in 1979. The new
M1, a passive sound-hole mount pickup, that senses top vibration
as well as string signal, is their first excursion into magnetic
pickups.
Features &
build quality
Unlike their competitors,
such as the Fishman and Sunrise pickups, which opt for the low-visibility,
matt-black look, L.R. Baggs have chosen to go with a proud-to-be-seen
light cream fascia, complemented by a dark brown body. Six black
steel pole piece screws and two countersunk Philips fixing screws
contrast against the cream top and as a finishing touch the L.R.
Baggs script logo is printed at the top right of the fascia, in
gold hot-foil stamp.
Build quality on this
product is absolutely first rate and the pickup is supplied with
a choice of two, Mogami, low-noise audio cables; a twelve foot
cable that terminates in a standard quarter inch jack for quick
and temporary installations, or a short cable with an end pin
strap jack for the more permanent installation. Both cables have
a 3.5mm mini jack that plugs into a socket on the end of the pickup
body and all connectors are gold plated.
This is a completely
passive pickup – no batteries or extra, specialised pre-amps
are required although, like any magnetic guitar pickup, running
the M1 into too low an input impedance will muffle the highs and
lower the output. L.R. Baggs don’t publish specification
figures for the M1, but measured D.C. coil resistance is only
1600 Ohms, which is unusually low for a magnetic guitar pickup.
This probably means each of the two coils has a resistance of
3,200 Ohm and the two are wired in parallel.
Installation
In size the M1 lies
somewhere between the Fishman and the Sunrise at 22 by 110 by
43 millimetres and is designed to fit sound-holes with a minimum
diameter of 3.5 inches (89mm). Like other sound-hole pickups the
M1 uses small clamps at each end that are closed by the fixing
screws, to grip the top of the guitar, at either side of the sound
hole. The lower jaws of the clamps are L shaped plastic parts
that engage in dovetail slots moulded into the body of the pickup.
These can be a little tricky with smaller sound-holes, because
at least one of the jaws may have to be removed and then juggled
back into the dovetail from inside the guitar. The jaws aren’t
padded because they need to be able to pick up the full range
of vibrations from the top without any damping. Providing the
clamping screws aren’t over-tightened, the smooth inner
surfaces of the clamps should not mark the guitars finish.
For temporary installations
using the long cable, the cable can be squeezed into a rubber
lined groove in the base of the pickup, clamping the cable for
extra security. With the two-cable plug-in system it’s even
quite easy to ‘borrow’ the pickup from a ‘permanent’
installation for temporary use in another guitar with the longer
cable.
Apart from the two
alternate cables Baggs supply a 3/32 inch hex key for pole piece
adjustment, two self adhesive cable clips and one 3/8 inch long
spare pole piece for use with string sets that have a plain steel
G string (the user leaflet lists an additional two spare ¾
inch pole pieces, but these seem to have been dropped from the
production shipments).
Pole piece adjustment - Balancing the string to body signals
Once the pickup has
been clamped into place it is EXTREMELY important to adjust it
for optimum sound quality. At first sight there appears to be
no provision on this pickup for adjustment of the balance between
the signal sensed directly from the strings and the body vibration
sensed by the lower coil. In fact the two signals can be balanced
by careful adjustment of the threaded pole pieces. The effect
this adjustment has on the quality of the sound from the pickup
is absolutely huge. Although this is mentioned in the user leaflet
supplied with the pickup, it’s easy to overlook just how
important this is.
We believe that this
pickup has received at least one less-than-glowing review in an
influential publication, where they complained of low output and
a presence peak that emphasised string noise, because the pole
pieces were not adjusted correctly. When we first fitted the pickup
we were alarmed by the degree of presence and subsequent degree
of string noise. Raising the pole pieces completely changed the
sound of the pickup and cured this problem.
As supplied the M1
has the pole pieces set to a starting position with the low four
poles in a staggered curve up to roughly 2mm above the surface
and the top B and E poles screwed down inside the pickup. This
allows for a reasonable volume balance between the plain and wound
strings and on a guitar where the strings lie quite close to the
top, will work fairly well. We installed the pickup on a Babicz
Identity Acute guitar and needed to raise the pole piece heights,
to a maximum of 5mm on the G string, to obtain a warm and balanced
string-to-body sound.
How the M1
works
Technically speaking
the M1 is a stacked humbucker design, where two coils are mounted
one above the other. Usually in such designs, the lower coil is
simply there to pick up any ambient alternating magnetic fields
and doesn’t sense any signal from the guitar. Because the
two coils are wired out of phase, any general ambient field, that
would otherwise appear at the output of the pickup as unwanted
hum, generate equal but opposing signals in the two coils and
are cancelled out. With the two coils stacked in this way, only
the top coil near the strings senses the magnetic field fluctuations
caused by the vibrating steel strings. In this respect the stacked
humbucker design operates and sounds like a single coil pickup,
with clearer highs and less bass than a side-by-side humbucker.
In recent years this design principle has been used in a number
of after-market pickups for the Fender Stratocaster electric guitar.
The Baggs M1 however has a further trick up its sleeve –
the pickup is designed to be intentionally microphonic and senses
a controlled degree of vibration directly from the guitars top.
Apparently the Sunrise pickup, an active magnetic sound-hole mount
pickup, which pre-dates the M1, has a similar top vibration sensing
feature, but little clear technical information is available on
the Sunrise.
In the M1 the second
coil is mounted in a tuned resilient mounting, with the freedom
to move in all three directions. Baggs refer to this as TriAxial
Dynamic Technology. When the guitar top vibrates, the pickup shell
and top coil move with the top, because they are clamped to it,
but because of inertia and its resilient mounting, the second
coil moves less. The relative movement between the two coils within
the magnetic field of the pickup, generates a signal current that
follows the top vibration.
Sound
Properly adjusted this
pickup sounds very good – smooth and warm, with just enough
presence to give a nicely articulated attack. The ability to sense
the top vibration adds a sense of air and an organic quality to
the sound.
Conclusion
The M1 is a fine pickup
and an excellent addition to the L.R. Baggs range of pickups,
offering a warm and organic sound with just a touch of presence.
Compared to the rest of the Baggs range, its standout features
are that installation is very simple and because it doesn’t
require specialised electronics and a battery, it’s very
straightforward to use. On the other hand since it is a passive
pickup it may not have as much output signal available as the
active units. Obviously it won’t suite those looking for
a pickup with minimum body noise sensitivity and some fingerpickers
may find that the pole pieces get in the way.
© Terry Relph-Knight
11-11-2004
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Amplifying
the acoustic guitar
From a purist viewpoint
the aim of pickup designs for acoustic instruments is to capture
a signal that, when recorded or amplified, sounds true to the
natural acoustic sound of that instrument. However almost all
the current pickup systems for amplifying the acoustic guitar
colour the sound in some way, sometimes to the point where it
sounds similar to an electric guitar. In practice this has led
to electro-acoustic sounds being accepted as useable and recognised
tones in their own right and even to a whole range of new playing
techniques.
Using a high quality
microphone is perhaps the best current method to obtain a ‘natural’
tone for amplified acoustic guitar. Unfortunately setting up a
high quality microphone on a stand isn’t always convenient
and is subject to feedback, ambient noise pickup, unwanted ambient
reverberation, unwanted pickup of string and pick noise, leakage
from other instruments and volume changes if the guitar is moved.
Current developments
in acoustic guitar pickup design acknowledge that microphones
provide a more natural sound because, even when positioned quite
close to a guitar, they sense the sound generated by the whole
instrument, rather than just vibrations from one part of the guitar.
They also ‘hear’ the guitar in context, through picking
up the ambient reverberation. Consequently many of the high-end
pickup systems use two or even three transducers to sense the
vibration from different parts of the guitar. However pickup designers
are finding that as their designs get closer to replicating the
virtues of external miking, they are also tending to exhibit its
vices, such as a greater tendency to feedback and the pickup of
unwanted noises.
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