Aston Microphones SwiftShield by Arthur Stone
What is it? Aston Microphones latest accessory is the SwiftShield – an easy-access mic suspension with integrated pop filter. There's also a Shield GN version (where the suspension is replaced by a gooseneck clamp) which is reviewed here.
How does it work? The popshield prevents the mechanical noise of moving air adversely affecting the mic capsule e.g. high energy sounds (pops) referred to as 'plosives' - the low-frequency energy of plosives can easily overload the mics input and this is worse for directional mics with a bass proximity effect. The Shield also disrupts the high-frequency phasing sound called 'sibilance.' The Shield also protects the mic from saliva.
The suspension prevents mechanical noise being transmitted from the floor via the mic stand: without adequate suspension low-frequency rumble or jitter (analogous to a camera without a tripod) will mar the recording.
The pop filter itself features a unique, solid stainless steel shield, with precise acid etched hexagonal filter holes, to give crystal clear vocals, with a perfect acoustic performance for plosive (pop) control. It also presents a large surface area and curves around the mic, so vocalist movement is never an issue. Ultimate pop reduction.
In addition to the advantages of traditional design and manufacture, Aston have utilised the capabilities of 'smart materials' to further improve isolation and protection of the mic. The new materials also offer advantages in mass-to-suspension performance (tuning the suspension to avoid resonance at the weight of the mic); product durability and lifespan; and weight.
The only potential downside of any popshield or suspension would be if it adversely affected the sound or left some undesirable character on the recording. Does the Aston variant do this? Does the tuned suspension and filter leave some detectable trace or unwanted artefact? For example, the wrap-around design might create a semi-cavity for resonance at specific frequencies; or reflections off the frame or surface. Generally, larger diameter popshields have less impact as the frame is further away.
A known characteristic of a traditional cloth popshield is high-frequency roll-off; but 'hard popshields' can resonate, and air meeting a barrier can create vortices and white noise: can the Aston SwiftShock with it's unique honeycomb design overcome this issue?
Price: $119.99 US; £105.91 UK; 177.66 Euro
What advantage does Aston's pop shield offer over traditional 'black-stocking' pop shields? It's 3D rather than 2D. Whereas a 120mm diameter traditional popshield has a surface are of approx. 11,300mm (150mm=17,670mm) the SwiftShield has a surface area of 21,330mm allowing greater coverage of the mic and allows the SwiftShield to be used off-axis which can be an important part of the vocalists technique especially with directional mics e.g. cardioid.
“We have reconceived the shock system, and as with all our products work from the ground up on an entirely new design idea. The ‘ShockStar’ suspension eliminates the need for fiddly rubber bands but offers a high level of elasticity for maximum isolation. As with all Aston products, the use of novel materials and our unique, architectural, approach to design is setting new standards for the industry.”
Smart materials for smart gear: The obvious applications here are in the strength and grip of the clamps; the way the mic floats in the 'smart elastic' which allows the suspension to be tuned to the mass of the mic; the general rigidity and proportional weight distribution of each system as a whole. These are not just design outcomes but also made possible by the novelty of the materials themselves.
Stainless steel (1913) is an 'early' smart material; basically chromium is added to produce steel (iron, carbon and a few bits) that wouldn't rust (oxidise). The root etymology of 'steel' means to 'stand firm' and this is what the thin sheet of the Aston Shield filter does.
Aluminium or Aluminum (1824), a chemical element rather than a mix of elements like steel, is molded to make the SwiftShock suspension frame; this is then machined to improve lightness and performance. James at Aston has discussed this being the most complex part to design and manufacture but that effort has paid off. Incidentally, Aluminum is the original term – the British decided to change it's name, adding the “i” in 1812 so as to harmonize better with the names of other metallic elements. Funksters eh?
Aston also use glass-filled nylon covering which feels smooth, dry and not sticky; it is a great improvement on 'sticky-rubber' surfaces.
Protection: The material and design Aston use makes the Shield easier to clean and arguably offers better protection of the mic from saliva which will be aerosol too....imagine a cloud of mist from breath on a cold morning in Wintertime.
Apart from the corrosive affect of the salts in saliva it's important to be able to prevent a build-up of bacteria or viruses on the Shield itself (which is more difficult with the complex microstructure of a cloth material of traditional popshields). Still gonna need a toothbrush to do it properly though...clean all them holes! With the addition of silver or copper, steel can become antibacterial (viruses are another matter) but the Shield should still be cleaned regularly to prevent nasties and present a fresh interface for the vocalist/client.
In Use: The Aston SwiftShock simply screws onto a mic stand, the Shield clips-on, and the mic is mounted by squeezing the clamp mechanism with thumb and forefinger and positioning the mic.
Aston have published a list of compatible mics which is limited but covers a good share of potential users. Popular microphones; Aston have obviously done their market research.
I didn't read the manual prior to use and intended to leave a Rode K2 tube mic mounted for a week and check for any potential slippage; it lasted 4 seconds! I had planned to do a filter shootout using a stereo pair of MXL770's with the Jim Williams RK12 mod – but they were too big to fit (although the MXL770XL's will fit). The advantage of using a stereo pair is that I could record an identical vocal and then try to null the audio files to look for differences.
Instead I recorded separate performances with and without the SwiftShield and another take with a traditional pop shield; I looked for words that typified problem sounds: pops and esses.
I also did a 'rumble test' – floor to stand vibration – with a traditional cats-cradle mount and the Aston SwiftShock mount.
Candle in the Wind: In the video accompanying the SwiftShield review we can see how certain words and phrases can agitate a candle flame and how this is lessened using a popshield.
I noticed that the candle reacts to the Shield presence more dynamically than the trad popshield but less than the original without a filter. The energy is tamed but the original dynamic character is still intact and I see that in the flame's profile. In comparison the candle image is super-stable with the traditional filter.
The conclusion then is that: no filter might overload the mic; the trad filter 'under-loads' it; and the Aston Shield strikes a balance.
Using the Shield made me aware of how the overload of no filter, and the muffling and inefficiency of a traditional filter, affects the mic adversely when under plosive energy – hear as a softening of the mid transient edge, like a sine tremolo as opposed to a choppy square wave. The Shield preserved the clear transient edge of the signal – sonic info that was lost without, either by the coupling and modulation of the diaphragm or the dynamic inefficiency and filtering of the trad popshield.
So the question is: when using a trad popshield what happens to the usable-level audio (vocal) that isn't excessively plosive or sibilant? It's filtered out by the inefficiency of the material. Particularly the good dynamics in the plosive regions.
Lost sonic info. It may never be heard but the Aston Shield assures it will be.
You got the Look: Visual acuity is something to consider with popshields: the vocalist may need to look at lyrics or score or at a DAW/info screen. In a group or ensemble, a good line of sight to other participants and instruments, meters, dials, etc. is important. No-one wants to have to look around the popshield between lines to check the lyrics. In terms of video or photography a traditional popshield can be problematic as it obscures the talent and can cast a shadow.
The SwiftShield's bright neutrality is a good new take on a traditional problem. The company logo is visible and whilst this is quite discreet I'd like to have some options e.g. plain or Celtic knotwork or Paisley, or custom-design even at extra cost. This might well be impractical for supply-chain logistics and in that event it's reasonably unobtrusive design.
The suspension frame and 'rubber bands' looks awesome - a work of tech art. In general a good impression for vocalists and not too intimidating as it has a friendly, classy vibe.
Linguistics and Physics: Concentrated plosive energy is re-distributed across the surface of the Shield; the high-frequency phasing of sibilance is interfered with, in effect, breaking up the sss's.
We can use linguistics, in a scientific sense, to look at the mechanical function of the products: products designed to alleviate or counter unwanted by-products of speech or song. We can look at the basic component sounds (phonemes), how the body produces them, then how they affect the audio recording. From there we can look at the specifics of how the popshield and suspension is operating.
The obvious disadvantage of the fixed-shield arrangement is that the shield cannot be moved in relation to the mic, and perhaps this is necessary to get the best out of a particular mic or tracking scenario.
As with the Shield GN (the gooseneck version of the SwiftShield) the internal arc could be prone to rear room reflections. I can see the SwiftShield being a good compliment to the Aston Halo or other filters which cover the rear. The popshield prevents the noise of moving air (from vocals) adversely affecting the mic capsule e.g. unpleasant harsh sss's or 'violent' plosive sounds , heard as pops; the low-frequency energy of plosives can easily overload the mic's input and this is worse for directional mics with a bass proximity effect; also the shield protects the mic from saliva. In mechanical terms, the aim is to prevent plosive energy from distorting the fragile membrane in the mic capsule and prevent resonant coupling between the membrane material and source during which the source frequency can modulate the membrane.
HexTech and it's roots: The regular hexagon is a common shape in nature: from natural quartz crystal to bee hive honeycomb to Saturn's north pole. Historically, the hexagon grid was recognised as the most efficient form of material construction, using the least amount of perimeter material and excellent strength-to-weight ration under compression. Maximum honey storage using the least amount of beeswax.
Hexagons and hexagonal geometry is ubiquitous and universal from the small to the large: snowflakes accrete as crystalline hexagonal formations bonded by electrostatic charge; or as ginormous intergalactic bubbles, man. Hexagons appear in lots of modern gear: from graphene sheets to computer fan screens to wind tunnels and turbines to space telescopes.
The use of the hexagon or 'HexTech' has two advantages in it's Shield application: first, the honeycomb design adds strength and lightness to the Shield's physical form; second, the hexagon is the preferred shape for wind tunnel filter design, mainly due to it's ability to distribute the load (air pressure/wind) across it's surface evenly...like soft honey in the comb or Saturn's stormy pole.
Once again, Aston's design and engineering is pushing the envelope.
Why use a pop shield? To make recordings sound better by preventing two common problems: plosives and sibilance. Effectively these are two separate sonic problems, with different causes, that can be fixed using one device.
The plosive problem is that sudden burst of air pressure energy from the vocalist (e.g. p or b) and this is stressing the thin diaphragm membrane beyond its comfort zone even 'shorting' the circuit by touching the backplate in a condenser mic. Electrical components further down the line might not cope with the sudden electrical energy coming from the diaphragm.
The recovery time of the membrane's oscillation (from the plosive shock) can also funk up the later signal, even cross-modulation can occur. That type of thing should be fixed pre-recording, not post. Another type of plosive issue is when spit/projectile-saliva directly hits the diaphragm or basket.
The sss's or sibilance (caused by sibilant phonemes or 'sound units') is a different problem both mechanically and sonically; less energy than the plosive so less danger of diaphragm stress but the main problem is in the signal itself - not in it's interaction with the mic. The energy in sss's can create a high-frequency phasing (around the frequency of a baby crying) which is not generally liked by listeners of music or media. Audio Kryptonite. Nail on blackboard. Overuse of Aphex Exciter. The sss's are also quite directional so good that the Shield is curved then!
Audio tests: I repeated the phrase “I'm not a pheasant-plucker...” and a few key words containing plosives and fricatives, into a WeissKlang V13 cardioid mic with the Aston Shield, with the traditional popshield, and with none (as a control): I then repeated the test in another position in the room and added a 'sung vocal' – the Welsh national anthem. Unfortunately there is not enough room to include that audio here ; D
In the first test I preferred the sound of the traditional popshield (which I was familiar with) as I thought I heard a metallic sound in the sibilant region which was confirmed by the spectrogram analysis. I repeated this test due to the noise; I wanted to see if it was a fluke of positioning or a characteristic of the Aston Shield. I also wondered if the Aston logo (which is solid material marked out by the laser-etched 'hexacones') could be acting in a similar way to a Biro, in disrupting the airflow of unwanted sounds/sonic behaviour?
Looking at sound: In the first test the Aston Shield GN produced a 5 kHz peak not present in the original signal or the trad filter take. Sonically, to my ears, it didn't sound like an improvement over the original or trad filter; the Shield sounded more metallic and the chart shows this as the 5 kHz peak (in faint blue).
I re-tested; same procedure, different position in room. The lower waveform is the average level and the upper the peaks. Not level-matched! Purple = Shield; Green=None.
Not much to say except the 5 kHz peak is gone and, levels aside, the Shield appears to be smoothing the original signal but retaining the clarity and brightness of the original signal.
To look at sibilance alone I focussed in on the word 'sis':
The first spectrogram has the output levels matched at -6 dBfs: there appears to be more energy in the 5 and 8 kHz region with the Shield.
The same take with the RMS levels matched confirms this:
I've attached all the comparison charts below if you're interested in specifics and although the visuals are just a guide they do confirm the sonics in this case.
Mea Culpa: It was quite a process making this review and thankfully Aston were generous with the time and space to do this: a two-week request turned in two months and more. I say thankfully because I discovered new things about acoustics and gear (which I can share with you) – I had a faulty or incomplete knowledge of sound/acoustics and I acknowledge that and move on. Mea culpa.
I made the mistake of comparing a traditional popshield with the Aston Shield when they are different: whereas the trad popshield filters out sound in the sibilant region it also colours the sound (cloth cap over ears) acting like a broadband EQ cut across the high mid frequencies...that's the sound I was used to. So when I first heard the Aston Shield (which doesn't filter but attenuates sibilance/plosives) I assumed it sounded awry and relatively metallic when, in fact, it was just representing the actual sound perfectly but without the plosives and sibilance of the source.
I made the mistake of judging the Aston Shield on what it was revealing about the source; the source being the vocal and room reflections/ambience and mic.
Some might accuse me of seeing the 'Emperors new clothes' – of confirmation bias or Ashe Effect – that really the Shield has a bright edge to it; but as anyone who progresses to 3-way high-end monitors or $1000 headphones notices, the increase in resolution and clarity reveals a faithful reproduction of the sound and that is what the Shield does. I think if you put this in front of a beautiful mic then you will hear that and not the filtering of a traditional popshield. The Shield is working more on the dynamics of plosives and sss's and not filtering them tonally.
So I think there is a cost to using the Aston Shield and that is it needs rear-protection from room echoes and a good quality mic and vocalist. If, like myself, you are looking for the Shield to filter out imperfections in mic/room or vocal then you'll be disappointed. This is pro gear.
An Inspector Calls: I may not be totally wrong in my insistence I can hear 'something' though. In the literature, wind scientists acknowledge the need for perfection in the honeycomb design, otherwise eddies and chaotic air turbulence can be created by the filter. At first I considered the Aston logo on the Shield: it's form comes from the absence of hexagonal holes; could this be creating unwanted turbulence and sibilant artifacts? Earlier I mentioned the old-trick (or old wives tale) about placing a Biro in front of the mic; that didn't make much of a difference, but it helped. Perhaps Aston had added the logo to actually assist in improving the signal?
Attention then turned to the fine detail of the join between the Aston logo cut-out and where the hexagonal holes retained their grid pattern. I started with a magnifying glass and then a x20 field microscope.
Whilst at a macro (eye) level of resolution the acid-etched hexagonal holes appear smooth and neat, under magnification burrs and striations are clearly visible.
Before I continue I'll say that Aston gear is not different from other gear in this respect, in fact it's generally better with high-quality, engineering design and manufacture – at any price. Finish is generally functional with mass-produced goods: if it can't be seen by the eye (or felt by the finger) then why increase costs?
Hearing is different from sight as the scale of resolution is independent of a qualitative aesthetic decision (“it looks nice”). Does it sound nice? - whilst still being subjective, is independent of resolution.
Wind tunnel designers noted that the burrs and imperfections in the honeycomb grid can cause anomalies e.g. pressure differentials, eddies, turbulence, white noise, etc. (rather than the aim of a consistent distribution of sound as air pressure across surface area of the filter). I believe I can possibly hear imperfections in the join between the Aston logo and the hexagonal grid and the higher-resolution examination shows possible culprits – the rough details causing chaos.
I did consider further audio tests including shotgun-mic'ing different parts of the Shield (regular hexagonal grid, and imperfect join) and recording a test signal but that's beyond the scope of the review really. Still, I'd like to hear a design that left the hexagons intact.
My other concern was about the rear-reflections entering the internal arc of the Shield. Perhaps I shouldn't have rear-reflections in the first place? The Shield is just being honest in this sense, and with a halo-type filter to cover the rear there would be nothing to potentially (or philosophically!) reflect; but without the halo I'm thinking that surely the internal arc of the filter will collect those rear room reflections and concentrate them directly into the mic like one of those death-ray mirror devices. I think I hear that anyway; just a bit too much emphasis in the sibilant region. In fairness, with time and experimentation, I think a sweet spot can be found.
Who's it for? I'm interested in hearing high-end mics them through the Aston Shield, particularly a ribbon mic. Even if using a different popshield the Shield is a useful tonal variant to have in the mic toolkit. Although I'm writing from a home-studio perspective I can see this ticking a lot of boxes for working studios; the SwiftShield will likely perform better in a controlled environment and bring out the best of the mic and acoustic space.
For beginners, this is a good choice but you'll need to put some effort into controlling room reflections and if shopping for budget mics you might need to match the mics tonality to the relative brightness of the Shield (in comparison to pop filters that darken the sound).
Sound quality: 5/5 Finely-tuned professional instrument; needs careful set-up for optimum performance. Very good on plosives; OK with sss's. Non-colouring.
Ease-of-use: 5/5 Care needed with placement and preventing rear reflections from entering the arc of the solid shield. The fixed-distance Shield to mic keeps position consistent although there is no room for manoeuvre. Time is critical when recording vocals; delays can kill the vibe...just a few seconds of distraction is enough and Aston's novel design helps keep things smooth and easy. Robust but classy. It does what a popshield is supposed to do, very well...and it's pushing things a bit further.
Features: 5/5 The HexTech system, robustness and cleanable finish add to the value. The suspension looks great and operates perfectly. It looks pro (logo included) and I'm sure it's more inviting to a vocalist than granny's tights.
Bang-for-Buck: 5/5 For the money you're getting a first-rate suspension with a lightweight machined aluminium frame; the super-elastic; and ease of access for hot-swapping mics or an easy set-up. Ninety quid for an effective, smart-looking suspension and popshield that'll probably last a lifetime? Perhaps not if you like the popshield to filter out stuff (although, in theory, you could put some material over the Shield if you like that sound) but the Shield will let you hear your vocals and gear as is.
Final thoughts: The Shield component improved the recording by taming plosive/sibilant energy; the candle test confirms this. The audio test shows effectiveness in taming plosives; sibilance slightly less so but it is easier to fix post-recording. If there is harshness in your vocal, mic or gear you will be aware of it; the Shield does not muffle the signal.
Although the comparison chart shows that the Shield appeared to emphasize frequencies not present at source it didn't appear to affect the final sound adversely in further tests. This may have been due to a particular placement but it also could have been emphasized by the arc of the solid shield. Either way, as always, care with mic/source/room placement is advisable.
Apart from the 3D wrap-around design the Aston Shield doesn't innovate over traditional popshields but it does improve a classic design/function and make it robust & easy to maintain.
There's a lot of wisdom in buying once and buying well to last; this is what the SwiftShield offers.
Links and credits:
Thanks to Voxengo for their wonderful SPAN analyser used in this review.
Phoneme - Wikipedia
Hexagon - Wikipedia
Honeycomb structure - Wikipedia
Photos used with permission of Aston Microphones Ltd; additional photos by Arthur Stone.
Wind Tunnel: NASA , Public Domain, https://commons.wikimedia.org/w/index.php?curid=6450048
Computer fan: By DonES - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1088016
Honeycomb: By Merdal at Turkish Wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=121469
Snowflake: By Thomas Bresson - Snow crystalsCC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=8805966
Snowflake (micrograph): By user:Brian0918 - Credit: Erbe, Pooley: USDA, ARS, EMU, Public Domain, https://commons.wikimedia.org/w/index.php?curid=493333
Saturn: By NASA/JPL-Caltech/Space Science Institute - http://www.nasa.gov/sites/default/fi...18274_full.jpg, Public Domain, https://commons.wikimedia.org/w/inde...curid=33952464