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What is the Reflexion Filter?
The Reflexion Filter is basically a portable device for recording live sound sources with reduced room ambience. It is an advanced composite wall which
is positioned behind any microphone by means of a variable position stand clamp assembly which ships with the product. The main function is to help obtain a ‘dry’ vocal
or instrument recording. This is especially useful in studios without proper acoustic treatment, but can also be used to help record takes in control rooms,
where the performer also has to operate the recording device, or in rehearsal studios to reduce ambient noise.
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STEVIE WONDER
‘I love the warmth, fullness, presence and the fat sound of the sE Gemini and every studio should have an sE Reflection Filter It's great for isolating sound and it's perfect for on the road.
''The Reflection Filter is exactly what I've been waiting for.’ |
The Technical Bit:
The Reflexion Filter has 6 main layers. Firstly, a strong layer of punched Aluminium which allows sound waves to pass through it, diffused, to a layer
of absorptive wool. The sound waves then hit a layer of Aluminium foil which helps dissipate energy and break up the lower frequency wave-forms, and from here they
hit an air space kept open by rods passing through the various layers. The air gap acts as an acoustic barrier. The sound waves then pass to a further layer of
wool and then through an outer, punched, Aluminium wall which further serve to absorb then diffuse the remaining acoustic energy.
The main absorber has 4 formed pieces of state-of-the-art specialist acoustic absorptive material attached to its face via the extended separation
rods, which further serve to absorb and then diffuse the sound waves as they pass to the main filter.
The stand assembly comprises a mic stand clamp fitting, which attaches by means of a vertical joint to the horizontal bar assembly onto which both
the Reflexion Filter, and any standard fitting shock mount can be fixed. The microphone (in its shock mount) can then be moved both vertically and horizontally along
the bar, and the Reflexion Filter itself can be moved vertically to obtain the optimum working position.
How does it work?
The various layers both absorb and diffuse the
sound waves hitting them, so progressively less of the original
source acoustic energy passes through each layer. This reduces the
amount of energy hitting un-treated walls and other surfaces so
there is less of the original source reflected back as unwanted
room ambience to the mic. The Reflexion Filter also helps prevent
any reflected sound reaching the back and sides of the mic. Its
shape and size have been carefully tested to maximize absorption
while keeping ‘coloration’ down to only around 1dB, and leaving
the microphone’s polar pattern unaffected.
The Results
'Independent test results from the Tongji University Audio Lab in
Shanghai show audio image colouration with and without the sE Reflexion Filter.
The tests (carried out by China's leading Acoustic Engineering
University completely independently) clearly show extremely low levels
of coloration when using a microphone with the Reflexion Filter while
recording (20Hz to 20KHz).
This was one of the greatest challenges in designing the RF. Other
companies have now started to try and copy our designs (without breaking
the patents which are what make the Reflexion Filter actually work!),
but fail to achieve such good results because the designs are too
simplistic.
The RF comprises several layers of Aluminium and patented acoustic
fibreboard separated by acoustically isolating air gaps... and therefore
manages to remove large amounts of room ambience with a very compact
design. The whole idea was to make the unit as effective as possible,
but in the smallest space... otherwise what would be the point... you
may as well treat a wall behind the mic.
The shape of the RF is also critical to the design as it randomises any
Reflections back from the surface of the filter. Products which are
semicircular (without the flat diffuser panels the RF has) will
concentrate any inconsistently reflected frequencies onto the mic... the
worst possible scenario.
Another very poor design though is a simple 'V' shape behind the mic.
This creates one of the worst coloration problems you can manage to
achieve when recording audio. Think about problems of Bass Accumulation
in room corners... the bass is accentuated worst in 90 degree corners,
so any baffle placed behind a mic which is this shape creates huge
coloration problems in bass frequencies. This also adversely affects
higher harmonic frequencies because of the massive energy in bass
frequencies exciting these higher harmonics. A simple flat panel on a
wall positioned behind the mic is a much better solution, as it does not
create coloration, but still limits at least some of the early
reflections in the room.
More independent test data will be available soon (approx Mid March).
For independent reviews on the performace of the RF please check our
reviews section.
In Summary:
All in all, it’s a very clever and desirable piece of kit. It allows you to record vocals, guitars etc with a ‘drier’ sound without having
to have an acoustically treated room. It’s portable. It uses state of the art materials. It works… and it’s a fraction of the price of acoustically treating
your studio environment!
Reflexion Filter is a registered Trademark. Patent Pending |