Rigging two fig 8s end-to-end for Blumlein or mid-side field recording in a Rycote Modular WS4.
With a pair of the final production versions of the BD-10s in hand, I thought it was high time that I followed up my earlier studio tests of the mics in a Blumlein pair with some field recordings. It’s not often you come across Blumlein pairs (or, indeed, mid-side pairs with two fig 8s) used for anything but music recording. I suspect this has to do with two different things: first, field recordists rarely have multiple fig 8s, perhaps only having one for mid-side recording; and, second, I wonder whether there is a bit of concern about the inversion of the rear ‘image’ of the mics. What might be a boon in the studio – arranging a group of musicians in an arc in front of the mic and doing likewise with a facing group to the rear, so that all combine beautifully into stereo with the rear musicians naturally flipped the right way round (listen to John Cuniberti’s wonderful OneMic recordings if this seems alien to you: and you can read about my Cuniberti-inspired recording of the Lucy Grubb band in an earlier post) – might seem problematic outside, where things usually can’t be controlled so well. What will happen if that bird sings from the front right instead of the rear left?! And what about those grey areas to the sides of the pair, where imaging transitions from the ‘correct’ to the ‘wrong’ way round: won’t the world in those areas come crashing down into a phasey mess? In a recording world where much about Blumlein and mid-side with two fig 8s puzzles beginners (and many who should know better), it is easy to see why the techniques see little use outside.
Just to kick things off for those not familiar with how Blumlein and mid-side with two fig 8s (which decodes to Blumlein) reverse L and R to the rear of the mic, here are two simple recordings (made indoors) in which I walk round the mic pair at the same distance, calling out the degrees as I do so. First up is a recording with a pair of BD-10s, in this case set up as an MS pair to allow simultaneous recording of a comparison with omni mid-side:
At face value the recording might appear to show that there is real reason to avoid using pairs of fig 8s: certainly, for example, a Blumlein pair (or mid-side with two fig 8s) wouldn’t suit recording a group of singers forming an unbroken circle around a pair of mics (which is essentially what this test did, albeit sequentially and, thankfully, without my singing involved!), although, nonetheless, some do this. But what single stereo pair of mics (as opposed to a surround set up) would work best for such a scenario? MS with an omni mid would seem obvious, although, of course, there would be no distinction between, say, 45 degrees and 135 degrees, and the equivalent this produces with a 50:50 ratio (i.e. equivalent to back-to-back cardioids) means that sensitivity of the pair isn’t constant around the 360 degrees. You can hear this in my second demonstration, recorded at the same time as the above test, but using omni mid side with a Rycote OM-08 as the front mic and a BD-10 as the side mic:
But what do most field recordings have to do with direct sound coming to a mic pair at equal amplitude from 360 degrees? Many, if not most, field recordings will involve sounds that are louder in one direction, or across an arc: a car or train passing, the main animal of interest in the foreground, a clearly localized person undertaking some activity. The full 360 degrees might be wanted for ambience, but whether a background bird rear left is heard front right in the stereo field rather than front left is likely to be immaterial: and, in the absence of surround sound, is mislocated anyway. Likewise, if the main focus of the recording is within the main arc of the Blumlein pair (say 70 degrees) then any ambiguity – and any phasiness – to the sides is of little significance. And what makes such care worth it for a Blumlein pair in the field? Well, the answer is twofold: first, Blumlein (or an MS fig 8 pair decoded to Blumlein) gives a uniquely accurate stereo image across those front and rear arcs; and, second, it does this while still recording sound from 360 degrees. In short, it’s another tool for the job: not suited in many cases, but useful to be able to deploy when the occasion arises, even outside.
Two BD-10s side-by-side in a stereo Cyclone: those markings are still useful for orientation even when not in an end-to-end configuration: at this point I hadn’t reversed the lyres or removed the rods.
Before even thinking of using a pair of fig 8s outside, the first thing is to house them in decent wind protection. This is a pretty simple matter with small SDC fig 8s like the BD10s, which can easily fit end-to-end in a fairly standard windshield: in this case a Rycote Modular Windshield WS4. This doesn’t have stereo cabling, of course, so you end up routing the second cable along the basket and have to squeeze it out of the cable exit by the end cap. Neither are major issues, but admittedly aren’t perfect. But as ex-BBC mid-side and Blumlein expert sound engineer Roger Long has long advised, it’s so easy to get bogged down in theory: practical experience – with ears with that have more finesse than mine – shows that the shadowing effect of placing two fig 8s side-by-side is essentially undetectable. This opens up scope for using more conventional mid-side rigs, and just using them vertically. The best fit windshield that Rycote make for their SDC mics is the Cyclone Stereo Kit 5, so that’s what I have used for the side-by-side Blumlein rig too: I made a couple of minor adjustments, rotating the lyres to remove a clunky bit of plastic away from the side-address capsules and also removing the metal rods that spanned between the lyres (and were redundant) so that I could then move the lyres closer together.
And here with one half of the basket attached, showing the lyres reversed and the rods removed, which is helpful for the BD-10s and essential for the shorter Rycote SDC mics (OM-08, CA-08 and SC-08).
With a couple of rigging options for outdoors sorted, let’s get on to some recordings. First up, here is one of my now all too familiar front garden recordings, with birdsong, my footsteps, cars driving past (crossing right to left), and a neighbour doing a bit of DIY.
Getting out of the garden, and picking up on the idea of testing a wide passing noise, here is a test on a track of a horse walking past. I was to one side of the track aiming the Blumlein pair (rigged side-to-side) across it, with the horse approaching from the right and walking past. The sound changes as the horse comes up to me for the simple reason that he veered onto the grassy verge to keep as far away from me as possible (who can blame him, seeing a bloke with headphones and a stand with a dead cat on it?!), but I think the recording still works and demonstrates that even from an angle of almost 90 degrees, passing through 0/360 degrees and ending at just over 270 degrees, the sound moves clearly across the stereo field.
Blumlein recording in the field (or a field!): the horse that whinnies in the recording below isn’t the miniature Shetland seen through the gate, but out of view, at over ninety degrees to the right.
In this next sample recording I set up in front of a field gate (see photo above), and you can hear me open and close the gate and then a horse whinnies in the distance. The horse was located slight to the rear of hard right so, due to the reversal of the rear of the Blumlein pair, appears to come from the front left.
Blumlein recording under an oak tree.
This next recording is a quiet ambience of surprisingly subdued birdsong, along – as gain was cranked up, with the distant sound of traffic, recorded under an oak tree in a fragment of ancient woodland.
Ok, so nothing stunningly conclusive here, but, I hope, food for thought. The attractions of Blumlein (and mid-side with two fig 8s) recordings for music are well known – at least among those making recordings of acoustic music in decent sounding spaces – but the approach can work equally well outdoors, even for 360-degree ambiences. Given that a pair of SDC fig 8s is not hard to rig in a windshield, either end-to-end, side by side, or fore and aft, it is easy enough to try if you have – or can get hold of – a pair of fig 8s such as the BD-10s. And, for my part, I have an upcoming recording session that combines acoustic music and the great outdoors – recording a pipe band – so will be including a Blumlein pair in tests for that: more anon.
The final production version of the BD-10 with its laser-etched alignment markings on the end.
Back when I was testing the Rycote BD-10 production version fig 8 mics with a Blumlein recording of Lucy Grubb’s band, my ageing eyes struggled rather with aligning the two black mics end-to-end at ninety degrees: what should have taken a couple of seconds seemed to take an age in subtle studio lighting. The fairly standard dot indicating the front lobe of the BD-10 is great for orienting the mic for mid-side recording, but I began to think how a few more discreet markings on the end of the mic body would help hugely with Blumlein or, indeed, mid-side with a pair of fig 8s. I sent off a quick Photoshop mock-up to the folks at Rycote and, a little to my surprise, they have run with the idea, laser-etching the four markings as shown in the photo above. I was so chuffed when a pair of the updated mics winged their way from Wilsonville, Oregon (where the Rycote mics are now made in the Audix factory) to rural Norfolk here in the UK. But I should say sorry, though, to those of you who had to wait a little longer for the BD-10 to start shipping as a result! A tiny detail, and a short post, but I hope others find the markings useful too.
Using the markings to rig a pair of BD-10s end-to-end.
NB see this post for my original review and tests of the BD-10
The Time and Mercy Band, comprising (left to right) Richard Ward, Jason French, Rob John and Kevin Burton.
Thursday evening was an inauspicious time to be heading out for a recording of a bluegrass band: it was a soggy wet evening here in rural Norfolk, with the narrow roads full of potholes lurking below rivers. It didn’t feel much like the Appalachian Mountains. Was it left, right, left, right, left and right again on the maze of roads around Mannington and Wolterton, or the other way round? And if I didn’t remember my left from my right, how on earth would I remember how to connect up the mics for some more mid-side recordings, building on my earlier comparative tests of the new Sennheiser MKH 8030?
I was heading back to The Forge, the studio of Kev Burton, where, a few months ago, I recorded Lucy Grubb and her band using a Blumlein pair of Rycote BD-10 fig 8 mics. This time it was a similar venture: a different band (albeit with the common factor of Kev on bass) – the Time and Mercy Band – and with a mid-side pair instead of a Blumlein pair. This was partly driven by only having a single pre-production Sennheiser MKH 8030 fig 8, but, also, because I wanted to test further the MKH 8030 in combination with the MKH 8040 cardioid as the mid mic, and throw the new Rycote BD-10 fig 8 and its cardioid (CA-08) sibling into the mix. Back at base, I’d decided that to compare the four mics in a mid-side array and allow any combination (but always using an immediately adjacent pair as mid and side mics), I needed a vertical array of five mics: that was BD-10 top and bottom, MKH 8030 in the middle, and the two cardioids between the three fig 8s. Getting them close together (I managed 4mm apart, which is better than many a back-to-back clip) was tricky and meant I couldn’t use individual shock mounts: but still wanting some isolation from a wooden floor and anticipated tapping feet, I then bolted the whole array to a pair of hefty (Duo Lyre 68 shore) Rycote Invision shock mounts, and, for belt and braces, put the stand on foam pads.
Heath Robinson would have been proud of this…
It was a little easier setting up than with the Blumlein recording, this time having all the musicians on one side of the mics and having no drum kit to manage in a fairly compact studio, but the principle remained very much as before – needing care to balance the different instruments and voices – for which having the studio’s control room, with its wonderful Midas desk (originally made for Frank Zappa) feeding into Logic, and Kev’s experience with it, was invaluable for reviewing each take. The primary feed from the mics was, again, to my field recorder.
We recorded three songs, but, for the purposes of this post I am going to focus on one, which the band call ‘Sugar Honey Babe’. It’s a traditional bluegrass song and has been recorded with many similar titles (and, of course, variations in the lyrics), and perhaps is most well-known nowadays as ‘Red Rocking Chair’.
OK, that’s more than enough preamble: to the results! First off, here’s a very quick and dirty video: one camera stuck on a tripod pointing towards the band and with the mics largely blocking the view of Rob on banjo. My excuse is that the focus was on the audio. The video switches between the various mic combinations and, as the previous tests showed that the two Rycotes are lighter in the bass department than their MKH 8000 series counterparts, a few options where the BD-10 and the CA-08 have some EQ: imperfectly applied, no doubt, but it reduces some of the more obvious differences between the mics. Other than the EQ on these few clearly labelled snippets, all the sound is as it was recorded: no reverb, no compression etc.
For those wanting to listen to the sound files without whatever YouTube does to them, here they are. I’ve not included the EQ’d versions as I am sure others can do better, or would at least want to try. These LR stereo files can, of course, be decoded back to the original mid and side channels, should you so wish (I’ve enabled downloading permissions on SoundCloud for them).
I’m not sure all the versions of the tracks with the Rycote mics given some EQ (as used where flagged up in the video above) merit inclusion, but here is just the one – the recording with the MKH 8040 and the EQ’d BD-10: although the EQ is fairly rough and ready, it does show the potential, should you wish it, to bring the mic nearer the MKH 8030.
And, finally, for a bit of fun, here’s a version of the video with the MKH 8040 and MKH 8030 pair throughout, rather than chopping and changing mic pairs. I’ve added a little reverb to this version.
So the verdict this time? As with the Blumlein pair recording, that’s one for others perhaps. The balance of the recording is far from perfect: we didn’t have endless time to fiddle around with placement, and, even if we had spent hours on it, it would have been hard to balance, say, Rob’s backing vocal and his (much louder) banjo. On a different note, rain can be heard on the studio window too: so not ideal. But putting the MKH 8030 into more real-world action with a largely acoustic band (there was a little bit of amplification for the bass) was useful, not least seeing how it performed with the MKH 8040 and just how much difference was noticeable when swapping out to different (and less expensive) mics, and what a bit of EQ might do to that. As before, my take is that the MKH 8030 is a first-rate mic, pairs well with the excellent MKH 8040 (as entirely expected), but that the considerably cheaper BD-10 is decent too and that, with some EQ, comes much closer to the MKH 8030 – especially when used as the side mic in a mid-side recording. As I’ve said before, it’s good to have these two new choices in the limited field of SDC fig 8 mics: happy days!
I’ve long been a fan of simple set ups for music recording, often using a mid-side pair only. That’s partly due to the fact that I like the idea of a stereo capture (rather than close-miced instruments and vocals panned across the left-right field), but also reflects the nature of what I do: location recording, with no studio and the natural tendency there – since the 1970s – to use multi-mic and multi-track recording, overdubbing and tinkering for as long as you wish. This is not to deny that there’s a hugely creative side to the typical studio recording approach, and it allows you to record instruments in ways just not possible without it. Of course, a simpler approach has remained the case with much recording of acoustic and classical music, although, even there, the number of spot mics can be vast these days. But recording of bands – with drum kits, electric guitars etc. – has been largely the province of the multi-mic and multi-track approach in recent decades, with only the occasional exception.
One such exception I have enjoyed has been John Cuniberti’s OneMic series of recordings. John is a hugely experienced engineer, with years of the studio multi-tracked approach under his belt, so it has been fascinating to see and hear his journey into a simpler approach: in his case using a stereo pair of ribbon mics, arranged as a Blumlein pair, in the form of the single stereo AEA R88. John has an excellent YouTube channel with examples of his recordings and videos, as well as behind-the-scenes videos, which are invaluable for others attempting something similar.
With a pair of the latest pre-production Rycote BD-10 fig 8 mics in hand, I was keen to try something in this vein: that is, to capture a whole band at the same time just with a Blumlein pair. Besides, what’s the point of a fig 8 mic without a good Blumlein work out? With a fraction of the skills and resources of a Cuniberti, expectations were much lower, but that’s not a reason not to have a go!
For anyone not familiar with the approach – which, like so much in stereo, goes back to the work of the brilliant engineer Alan Blumlein in the 1930s – a Blumlein pair comprises a pair of fig 8 mics usually arranged directly one above the other, so that the two mic capsules are angled at 90 degrees to each other: in that sense, like an XY pair. This gives you a stereo field in front of the mics and, with the rear lobes of the mics, to the rear: the stereo field to the rear, of course, is flipped. There’s plenty of signal at the sides of the pair, but it’s not the place for a direct sound source: at right-angles to the pair a source would be, say, on the left from the perspective of the front lobes, and on the right from the perspective of the rear lobes. Quite evidently, a recipe for a phasey mess. So, a Blumlein pair isn’t the answer to micing a group ranged in a circle around the mics, but does let you spread them in an arc of 70 degrees in front of the mic and a similar arc to the rear. Setting relative levels of different instruments and vocals is, needless to say, a question of adjusting loudness of the sources and/or distance from the Blumlein pair.
So much for the theory: the task is to translate that into action. With Lucy Grubb and her band willingly volunteering for the exercise, choice of venue was largely dictated by the need for good monitoring: with ‘mixing’ created in the setup, it was essential that the band and I could listen back and adjust the set up as necessary. The bassist, Kev Burton, happily let us use his studio – The Forge – where the band has previously recorded their multi-track releases: the wonderful Midas desk (originally made for Frank Zappa) was reduced to monitoring duties (from a passive split and feeding Logic), while the primary feed from the Blumlein pair was to my Sound Devices MixPre-3 recorder. Kev’s experience with his studio and the expert ears of the band were crucial to getting the balance right.
Monitoring in the control room, through the Midas desk, Logic and some Tannoy Little Gold monitors.
It was a tight squeeze in the small studio, with the hardest thing controlling the level of the drums, even with brushes and a special kick-drum beater: there was only so far we could move the drums away from the mics, so the drummer, Paul Weston, detuned his snare to great effect, and we put a gobo in front of the kit. The electric bass amp was placed on a chair in front of that (to get the bass central and nicely balanced with the kick drum), with Richard Poynton, on electric guitar and singing backing vocals, nearer the mic, and a little to one side. Closer to the mic, but centrally on the other side, was lead singer (and song-writer) Lucy Grubb, playing acoustic guitar (with a little amplification behind her). Left and right of her amp, were amps for Richard’s guitar and for the keyboard of Piers Hunt: all three were on chairs/beer crates to get them off the floor. Placement of the keyboard and the bass players themselves didn’t matter: it was all about the position (and volume) of their amps.
Getting distances and angles from the mic pair for lead and backing vocals was essential: Richard’s guitar amp (a Fender Champ) was at the same angle to the mics as his guitar, but on the other side of the mics, behind Lucy.
There was precious little room for any lights or cameras, but, nonetheless, a rough and ready film of the recording seemed worthwhile, so here – with a video of one of the three songs we recorded – is what I managed. The sound has seen no processing other than addition of a little reverb: there is no compression, EQ etc.
So the verdict? Well that’s one for others perhaps. But from my perspective and, more importantly, that of the band, what we got was a very faithful sound of the band in the room. Everyone was engaged in the idea of balancing or ‘mixing’ at source and I suspect we’ll be back having another go before long. Oh, and the BD-10s faired rather well as a Blumlein pair, I thought!
A new addition to the Rycote family of SDC mics: the fig 8 BD-10 (right), together with some of its siblings.
Introduction
For anyone who has been following the foray of long-established and respected maker of mic windshields and suspensions, Rycote, into manufacture of mics themselves, the announcement of the BD-10 fig 8 at NAB 2023 is an exciting development. With two shotgun mics produced in 2021 and then, in 2022, omni, cardioid and supercardioid mics, a fig 8 mic was undoubtedly the most hoped-for mic to give a reasonably complete range. You might wish for a wide cardioid too (or variations on the existing polar patterns – a free-field omni mic, for example), but there is no doubt that a fig 8 mic is vital to Rycote’s range of mics for several reasons: first, Rycote’s established customer base is founded on field recording and, especially, those recording sound for film/television, where mid-side recording – and a fig 8 mic – is a key tool; and, second, the company needs a full range if it is to tempt users away from more established manufacturers. That there are few such complete ranges, with a fig 8 mic in the sub-£1000*mic category adds to the significance of the BD-10: with the recent demise of AKG’s competent Blueline mics (launched 30 years ago), I can’t think of another manufacturer producing mid-priced SDC mics with a fig 8 in the line-up other than boutique Taiwanese mic-maker B9Audio (with almost no reviews and mics only available direct from a private address in Taipei, B9Audio is not viable for most) and, possibly, respected German manufacturer MBHO (I say possibly, since the MBHO website has long since failed to list the KA 800 fig 8 capsule, pricing is uncertain, and, again, distribution is not similar to most mainstream mic manufacturers: for example, I can’t find any MBHO mics in stock in the UK). And one-off SDC fig 8 mics (i.e. not forming part of a range of polar patterns) in this category are rare too. Perhaps more surprisingly, not all mic manufacturers producing SDCs in higher price brackets have succeeded in producing a fig 8: most obviously, Sennheiser has never managed to bring a much-anticipated MKH8000 series fig 8 to market (although the excellent, albeit large for an SDC mic, MKH30 has remained in production since launched in 1987), and DPA similarly has no SDC fig 8 offering.
*NB: though Rycote has yet to announce pricing, it will almost certainly be in this category, but perhaps a little pricier than its £670 SDC siblings.UPDATE 1 Feb 2024: the BD-10 is now being listed in several respected stores here in the UK, most with a price of £638 (inc. VAT), and nothing higher than this. I’ve even noticed some MS kit deals – BD-10, super-cardioid SC-08 and Cyclone windshield for £1500 (inc. VAT). So, it looks very much to be good news on the pricing.
A mid-side pair of the BD-10 and the cardioid Rycote CA-08.
The Rycote BD-10, on paper, then looks like it will be a welcome addition to the market, when it becomes available (probably not until the autumn). Its self-noise is comparable to that of the Schoeps MK8. It is a little (22mm) longer and heavier (15g) than Rycote’s omni, cardioid and supercardioid mics, but not radically so. This reflects the capsule design, which, I understand, is a pairing of 11mm diameter diaphragms one above the other with a waveguide to blend them: the polar pattern graph shows a very symmetrical result from this arrangement, but, of course, the proof of the pudding is in the eating. So, what is the mic like in reality? On to some field tests and trials.
NB The mic tested was a prototype, and the final specs of the BD-10 in production may differ slightly.
A tantalizing glimpse into the BD-10: hard to work out the capsule design without disassembly!
RFI
As with all mics, I was interested in the impact of radio frequency interference (RFI) on the BD-10. Living in rural Norfolk, much of my life is outside or on the edge of mobile phone reception, where some models of phones transmitting at full power can cause notable interference on mics at up to, say 1m/3ft: not a problem with mics on a stand, but I’ve had this become a real issue with handheld shotgun mics and a phone in my jacket pocket (on those rare occasions when I forget to turn my phone off). And this could be a problem with ENG work too (not least from the phone of an interviewee). So I was glad to find that in testing, as before, with several different phones on the absolute fringe of reception (i.e. working at highest power) the mic showed no sign of RFI even at close distances (100mm): the other Rycote mics are similarly resistant to RFI.
Self-noise and sensitivity
With an 18dBA self-noise figure the BD-10 has significantly more self-noise than its stablemates, which are the HC-15 and HC-22 shotguns at 8.5dBA; the omni OM-08 at 11dBA; the supercardioid SC-08 at 12dBA; and the cardioid CA-08 at 13dBA. The previously released Rycote mics, however, have unusually low self-noise, and higher self-noise for SDC fig 8 mics is normal. For example, at 17dBA the Schoeps MK8 has a very similar self-noise figure to the Rycote fig 8, and, again, 7dBA more than its MK 2 omni capsule counterpart (10dBA). In short, the BD-10 is in good company and 18dBA self-noise for a fig 8 is respectable.
A check on the reality of the 18dBA figure – by recording the sound of nothing (the mic buried deep in duvets in the airing cupboard, with all doors and windows closed and the mains electricity turned off, recording into a Sound Devices MixPre-3 [EIN -130dBV/-128dBu]) and with reference to other mics – confirmed that the self-noise is indeed around that stated.
Testing this in the real world, I rigged the BD-10 as an MS pair with a cardioid CA-08, and a second SDC fig 8 in the form of the AKG CK94: the latter, although just discontinued, is a rare example of another sub-£1000 SDC fig 8 mic with a full frequency range.
First off, recording the ambient sound of my nominally quiet Norfolk village street (yet again!) even in the quieter parts there is no evident difference between the two Rycote mics, but hiss from the AKG CK94 is clearly discernible, which reflects its 22dBA self-noise spec.
Turning to a quieter environment, it was useful to test the BD-10 indoors, in this case with some sound effects/indoor ambience: the mic was set up as a mid-side pair with the cardioid CA-08 in the middle of the kitchen, with various household noises – and some silence – recorded. The AKG CK94 was also paired with the CA-08 for comparison. Here are the two MS tracks and then the three iso tracks for the cardioid mic and the two fig 8 mics:
During the sounds such as cutlery being placed in a drawer the two fig 8 mics are both very usable, but in the quiet passages, such as near the end, the hiss of the AKG CK94 is, again, fairly evident.
The specs state the BD-10’s sensitivity as 14.2mV/Pa (-36.95 dBV). This means that the BD-10 is the least sensitive of the Rycote mics (the next being the cardioid at 24.3 mV/Pa or -32.3 dBV), but its output is still healthy. For example, it is more sensitive than the Schoeps MK8 (12 mV/Pa or -38.5 dBV) and the AKG CK94 (10mV/Pa or -40 dBV). A consequence of this is that the BD-10 has a couple more dB max SPL than its stablemates, but the more practical reason for being aware of its sensitivity is for level matching against different mics when using the BD-10 in an MS pair (matching sensitivity in the recorder in such use giving an easier starting point for monitoring and in post).
Frequency response and ‘sonic signature’
Fig 8 mics generally have a poorer bass response, although some, such as the Sennheiser MKH30 are exceptions: in this case pretty much flat down to 40Hz. The main competitor pricewise to the BD-10, the Ambient Emesser ATE 308, has a marked bass roll-off from 100Hz (if not higher), which is fine if matching for MS to a shotgun mic that has a similar roll-off, but is not ideal for other use. More surprisingly the much-loved Schoeps MK8 has a steady fall off starting from above 200Hz, and, according to its frequency response graph, is down 8dB by 50Hz: at the high end there is a sudden fall-off from 16kHz, so that the response is down by 20dB at 20kHz. The more modestly priced AKG CK94 has a less curtailed frequency response than most of these examples (bar the MKH30) being down about 3.5dB at 50Hz and a similar amount at 15kHz (with no published data beyond). On paper, the Rycote BD-10 looks hopeful: the frequency response graph shows a very gradual roll-off from 200Hz so that it is only -1dB at 100Hz, -2.5dB at 50Hz, and -4dB at 20Hz. If the graphs are correct, then this suggests, a little surprisingly, that the BD-10 has a better bass response than the cardioid CA-08 and supercardioid CS-08. At the upper end, after a little rise around 12kHz, the BD-10 is down about 5dB at 20kHz.
So much for the theory: now to reality! First, a different take on the ambient recording, in this case with the two fig 8 mics (i.e. Rycote BD-10 and AKG CK94) oriented so that in each case one of their lobes faced the rear of a parked car and, in a separate blimp, the SC-08 cardioid likewise facing the car, which was then started. The resulting mono tracks show all three mics capable of rendering the lowest fundamental (at the lowest engine idling speed around 24Hz), with the BD-10 showing more low frequency response than the AKG CK94, but slightly less than the cardioid CA-08: this isn’t a surprise in terms of an expectation of a fig 8 mic versus a cardioid, although it is not what would be anticipated from the frequency response graphs. Graphs aside, though, it is clear that the BD-10 has a good bass response for a fig 8 mic, which suggests good capability for, say, music recording or effects and field recording with a bass component.
At the upper end, it was interesting to see if the BD-10 had any of the extended high-frequency response found in testing of the other Rycote SDC mics. As with the comparison of the Rycote OM-08 and Sennheiser MKH8020 omni mics for extended high frequency response, I recorded a street ambience at 96kHz instead of 48kHz, in this case including the OM-08 and the AKG CK94 alongside the BD-10 for comparison, with levels adjusted to reflect the different sensitivities. As with the omni mics comparison, again the spectrograms are revealing: they show the extended high-frequency response of the omni OM-08, as now expected, with, for example, the gate latch-shutting sound (that tall spike near the right-hand side of the spectrograms) reaching about 48kHz, and the wider spike of the passing tractor (towards the left-hand side of the spectrograms) reaching around 35kHz, and, as would be expected, with much more low-frequency content. The BD-10 shows both clearly, showing that the different capsule design for the fig 8 mic still has a very respectable extended high-frequency response to near 48kHz: moreover, the BD-10 is like the OM-08 in that it is consistently low in terms of self-noise up to the top of the graph (around -136dB at 48kHz) in stark contrast to the previous comparison of the OM-08 and Sennheiser MKH 8020 (where the Sennheiser had considerable self-noise in the extended high frequency range, although not, of course, in the human audible range). The AKG CK94 has a rather lower extended high frequency response, although rather better than anticipated from previous tests on the other Blueline capsules, and has a little more self-noise at such frequencies (as, of course, it does in the audible range). As discussed previously, extended high-frequency response might seem entirely academic outside those recording at high sample rates and pitching down in post (e.g. for bat recordings, or for sound effects), but there are those that argue frequency response over 20kHz is important for high-resolution recording (such as David Blackmer of Earthworks mics in this article). If so minded, there is no doubt that the Rycote fig 8 is a respectable performer over 20kHz, comparable to the other Rycote SDC mics, and with much lower self-noise a useful benefit of the not quite as far extended high-frequency range as found in the Sennheiser MKH 8000 series mics.
Spectrogram of the ambience street recording showing frequencies up to 48kHz: Rycote OM-08 left; Rycote BD-10 centre; and AKG CK94 right.
Putting this good low and high-frequency response to practical use, I tested the BD-10 on a guitar to cover a wider frequency range. At the same time, given that the previously produced Rycote mics are described by the manufacturer as having ‘a tonal and sonic signature that makes them cut together seamlessly’ and that this relates to frequency response, I also included the omni, cardioid and supercardioid mics in this test, placing mics at the relevant increasing distances to allow for their different polar patterns to reduce the impact of different reflections: the omni mic was placed at 400mm, the cardioid and fig 8 at 680mm (distance factor of 1.7) and the supercardioid at 760mm (distance factor of 1.9). To make comparison most straightforward the wav file has a single strum from each mic in turn (omni, cardioid, fig 8 and supercardioid in turn), followed by a short space and repeated another three times. This was carried out in a normally furnished living room, with a low ceiling.
Setting up the mics at relevant distance factors for comparison with guitar
It is hard to draw definitive conclusions from this simple test. Matching levels was extraordinarily difficult given the different frequency content and different reflections resulting from the different polar patterns, distances and frequency responses: in the end I settled for calculating the impact of the differences of distance and sensitivity. There is, as would be expected, a slight change in the sound as the polar patterns and distances change, and, despite being at the same distance, there is a difference between the fig 8 and the cardioid mic: to a significant degree this is the impact of the greater bass response of the cardioid. Interestingly, the fig 8 and the supercardioid have a very similar sound, doubtless reflecting the reduced bass response of the latter (and, of course, its greater distance: less proximity effect). In short, though, the ‘sonic signature’ for the mics is close enough that I wouldn’t hesitate in using the BD-10 with any of the other mics in a mid-side or double mid-side array.
Handling noise
The BD-10 will have a wide range of applications, but this is likely to include use on a boompole in a MS or DMS rig, so handling noise performance is relevant: all other things being equal, fig 8 mics are the most susceptible to handling noise. Testing for handling noise transmitted via a boompole involved some deliberately clumsy booming, aiming for transmission of vibration to the mics. Three mics were included in the test (i.e. rigged together on a Rycote Invision suspension with back-to-back clips) to allow comparison: the Rycote BD-10, the Rycote SC-08 (supercardioid) and the AKG CK94 (fig 8). Gain levels were adjusted for relative sensitivities.
When holding the boompole still only the BD-10 showed any significant handling noise, which peaked at -38dB, with LUFs at -68.7dB. Evidently this was trembling/vibration from the boom operator’s muscles holding a steady stance, and was all low-frequency energy below c.35Hz: a high-pass filter – a pretty essential adjunct to booming – removes such energy. In the second recording of boompole handling an 80Hz high-pass filter was applied and the low-frequency content in the BD-10 recording is absent: in this case, however, some medium clumsy handling transmits more to the mic than to either the SC-08 or the CK94, which perform very similarly (about 10dB lower noise in terms of LUFs compared to the BD-10). In the third boompole handling test, with extreme rough handling – rather implausibly so! – the difference between the BD-10 and the other two mics remains similar at around 10dB. While previous tests against the AKG CK93 and Oktava MK012 hypercardioids revealed the SC-08’s ability to cope with handling noise rather better, it is clear that the BD-10 doesn’t perform as well as its stablemate or, indeed, the AKG CK94 fig 8, but, other than that sub-c.35Hz transmission – which can be easily cut off by use of a high-pass filter at 40Hz or above – it should offer no problem to the user given a suitable suspension and experienced boom operation (not forgetting that capture of stereo ambiences on a boompole is usually for incidental B-roll, camera perspective stereo etc., not whilst executing complex and rapid boompole movements for dialogue recording!).
Wind noise
Fig 8 mics are especially susceptible to wind noise, so it is interesting to explore this aspect of the BD-10’s performance. To get a base line, a triple rig of BD-10, SC-08 and AKG CK94 was used again, this time, however, with the mics in separate Invision suspensions, spaced along a stereo bar so that no mic was shielded from the wind by the others, and mounted on a boom pole. Fast boom swings were made to generate wind noise, not to represent typical usage of a fig 8. Gain was set as for the handling noise tests (see above). Swinging the bare mics produced overwhelming rumble, as would be expected: the SC-08 and BD-10 performed very similarly, while the AKG CK94 performed rather better (about 13dB better in terms of peak and LUFs). Of course, such use is unrealistic: even with a modest amount of boom movement indoors (or the gentlest air movement around a static mic indoors) at the very least a foam windshield would be used, so the test was repeated with the manufacturer’s original foams on all three mics. Again, the two Rycote mics produced similar levels of wind noise, with the AKG CK94 maintaining an advantage of around 13-15dB. Applying an 80Hz high-pass filter on the recorder in the third test evened things up rather, with wind noise much reduced and with the AKG CK94 having around a (reduced) 5dB advantage over the two Rycote mics. As was noted in the previous SC-08 wind tests against the AKG CK93 and Oktava MK012, it performed between these two mics in terms of noise and, in extensive use since, has not proved problematic. That the BD-10 performs similarly, despite its fig 8 pattern, is reassuring: of course, better wind (and handling) performance at the level of the CK94 would be welcome, but there is no reason to think that the BD-10 isn’t suited to use in wind given, as with any mic, suitable wind protection for the use and conditions.
A dead cat and two live dogs: testing in a very brisk wind on the Norfolk coast
Following up on this and placing the mic in high wind for an ambient recording confirmed this. I took a mid-side rig with the SC-08 and BD-10 mics in a medium Cyclone windshield up to the north-facing Norfolk coast on a windy day (about 20 mph or more), recording in one location on the inland side of the shingle spit, facing westwards into the wind (including some walking nearby on the shingle), and in a second location on the beach (the wind coming from slightly rear of the left-hand side of the Cyclone). Finally, back in the garden with the same rig and with the wind still blowing (but inevitably not as hard as at the coast), I then did a further recording. For the recordings, I include the individual SC-08 and BD-10 isos, along with the decoded MS and then the latter with an 80Hz high-pass/low-cut filter applied.
It is always hard to translate and communicate conditions let alone those in high wind. In none of these cases would I have attempted a nature/ambience recording as set-up for these tests: I would have sought some shelter from the direct blast of the wind (e.g. in the lee of the pillbox on the beach, or in the lee of the garden wall), not least to reduce vibration of the mic stand. But what the tests do confirm is that the BD-10 is in the same ballpark in terms of wind noise as, say, its supercardioid counterpart. In short, I’d have no hesitation using the Rycote fig 8 for outdoor field recording.
A bit of music
I recently wrote a blog post about a simple video of a singer-songwriter (Lucy Grubb), for a competition entry, and, though I mentioned use of a variation of double mid-side recording, I skipped over just what fig 8 mic I was using. As it is no longer under wraps, it is good to be able to clarify that I used the new BD-10 alongside its supercardioid (SC-08) and cardioid (CA-08) stablemates. Using the three mics, the fig 8 was set conventionally pointed at Lucy, just above the top of her guitar, so that its lobes faced left and right; immediately below this the supercardioid pointed upwards to capture the vocals, and immediately above the fig 8 the cardioid pointed downwards to the guitar – aimed around the 12th fret.
Conclusions
When Rycote followed up on its initial two shotgun mics of 2021 with its omni, cardioid and supercardioid mics the following year, this gave real hope that a fig 8 might follow. Evidently, the capsule design is very different to that used in the other mics, so all the more credit should go to Rycote for persisting. As I said at the outset, a fig 8 is critical to the use of so many recordists that use Rycote’s windshields and shockmounts; and it is important if Rycote wants to be seen as a real contender as a mic manufacturer. That Rycote has come up with a fig 8, and fairly quickly, is good news: that it performs so competently means that it is a great counterpart to the rest of the range. Over a couple of months (intermittently) testing the mic, I have been impressed: I will, however, continue to work with it, not least putting it through its paces on more musical sources, and more field recording.
