Audio Gear – Page 5

A tale of two MKH 8030 mics, a native B-format array and a pipe band. Part 1: the mic arrays.

August 4, 2024

Some of the members of the City of Norwich Pipe Band at Wymondham Abbey for the recording test.

Introduction

A happy coincidence of an interesting recording project and the arrival, a few weeks ago, of a second MKH 8030 fig 8 mic from the folks at Sennheiser set me thinking. The recording was to be of the City of Norwich Pipe Band: that is bagpipes and drums (side/snare, tenor and bass). Pipe bands often play in a circle, so they can all see each other, and for this recording the plan was to maintain that approach in broad terms. The circular formation, with the band members’ backs to any audience has given the BBC’s sound engineers a challenge when recording the world pipe band championships outdoors in Scotland each year. At that event they are obliged to record outside the circle formed by the band (who, to make things yet more complicated for recording, march forward while playing before forming the circle), making the best of a difficult situation. For this recording, which was not in the context of a competition or, indeed, a public performance, I had the advantages of a static pipe band, being able to place mics inside the circle, and, also, being able to tweak that circle idea a little bit.

Both the recording of a pipe band and the recording a group of musicians in a circle, or near circle, are challenges, and in this case extra complexity was introduced since the overarching aim was to do two test sessions, one inside and one outside, as a prelude to possible recording of a CD (opinions generally are a little split on whether a pipe band should be heard/recorded indoors or, in its more natural habitat, outdoors). Rather than one overly long write up, I am breaking this down into separate blog posts: this first one explores the mic arrays used, and the second discusses the recordings from the indoor test (and includes samples of them).

Options for recording musicians in a circle

There are various ways to tackle recordings of a circle of musicians, with the end results ranging from mono to surround sound: in this case we were after stereo. Obvious options for such recordings would be a Blumlein pair or mid-side with two fig 8s; omni mid-side; double mid-side; and a spaced pair of omni mics. The last three options would work with a full circle (though omni mid-side suggests flattening the circle a little front and back, due to less sensitivity of the back-to-back cardioid pattern of the resultant, decoded, LR stereo pair). And the Blumlein pair or mid-side with two fig 8s options suggest modifying the circle to form two opposing arcs, say of 70-90 degrees each, avoiding any direct sound from the musicians in the more difficult (i.e, phasey) side quadrants. Choosing from these options is not easy as there are pros and cons. Blumlein or mid-side with two fig 8s (which mathematically decodes to Blumlein, but which inevitably sounds a little different) offer the prospect of excellent stereo imaging, albeit with the reversal of the rear side (not an issue in this or, indeed, many situations); omni mid-side and spaced omnis offer the prospect of a better low end (relevant here to the bass drum); and double mid-side offers the scope of having different mid-mic polar patterns front and rear and, more significantly, the option of changing respective levels in post (useful for tweaking the balance of the drums and the pipes on either side of the circle). Well, given that this was to be a test recording, the obvious solution was to do all of these options simultaneously. This didn’t require a proliferation of mics vying to be in the same place at the same time, but, rather, a simple set up of three mics in a pantophonic (i.e. horizontal, or 2D) native B-format (WXY) array for all the coincident mic options, flanked by a pair of omni mics to cover the spaced-pair option. So five mics in total.

Spaced pair

The spaced pair of omnis option hardly needs much explanation, as it will be familiar to most, if not all, readers: the key points here being aiming the mics upwards to get an even sound in all horizontal directions (omni polar patterns being increasingly directional at higher frequencies), deciding on setting the height (with no musicians behind others and wanting to get a balance between upwards projecting drones at the rear of the pipers and downwards pointing chanters at their fronts, and to avoid over dominance of the snare drums (or, in the first test, single snare drum), I settled on 1500mm), and choosing a spacing. For the latter, with the full circle I wanted a stereo recording angle (SRA) of 180 degrees, so that meant a spacing of 510mm or less: I went for 460mm. For the two arcs, however, it made sense to narrow the SRA to match a Blumlein pair (i.e. 76 degrees) so that meant a spacing of 840mm. And for the mics, not having two more MKH 8020s, I settled on a pair of Rycote OM-08 mics.

Coincident arrays: Blumlein, mid-side, double mid-side, and native B-format

The native B-format set up is likely to be less than familiar to many readers. B-format components (W, X, Y and Z) can be derived from the A-format outputs of the tetrahedral (or, indeed, octahedral) arrangements of ambisonic mics, such as the Soundfield. With ambisonic mics, the W, X and Y components (we can dispense with the Z or height component here as irrelevant to our stereo end product) are derived from combining the different capsules, creating three virtual mics – forwards and sideways facing fig 8s (X and Y respectively) and an omni (W). A native B-format set up, needless to say, just uses two real fig 8 mics and a real omni mic. The combination of mics allows all of the planned coincident arrangements to be achieved and, indeed, allows the array to be steered: perhaps not that relevant in this case, though this could be handy for some circular set ups. The native-B array, which today can be found in single mics such as the Josephson C700s (for a cool £7,600), was pioneered by Dr John Halliday at Nimbus Records and is often referred to as the Nimbus-Halliday array: the two fig 8s (vertical and end-to-end) are separated by a forward-pointing omni mic. Such an arrangement wasn’t ideal for the purposes of this test: first off, in the Nimbus-Halliday array the omni is facing forwards, so the sound will be different from the rear; and, second, the mics aren’t as coincident as they could be (thinking here of comb filtering that will concern the purists) for some of the two-mic options first envisaged for this pipe band recording. For example, the two fig 8s, if used for mid-side, are separated by the omni mic, which would result in 54mm centre-to-centre spacing with two MKH 8030s: better than 68mm with a pair of MKH 30 fig 8s, but far from ideal. Taking suggestions by Daniel Courville and Paul Hodges of swapping the omni with one of the fig 8s (to remove the directionality of the omni mic at high frequencies) helps, but this can be much improved by rotating the whole array by ninety degrees, which swaps the orientation of the two fig 8s. This then gives a spacing of the omni and forward-facing fig 8 of 16mm centre-to-centre: very effective when combining these two mics to make a cardioid or, in different proportions, any other polar pattern for the mid mics in double mid-side. And the two fig 8s (thinking of mid-side with two fig 8s) become set at 27mm centres (half what they would be in the Nimbus-Halliday array if using the same mics); and, finally, the two most distant mics, the omni and side fig 8 (for omni mid-side) are at 43mm centres. Turning the omni vertical evidently reduces the high-frequency response in the horizontal plane a little, but, if required, a little high-frequency lift could be added. I didn’t anticipate this being much of an issue with bagpipes and snare drums: a little reduction in such frequencies could well prove useful. In terms of elevation of the array, this followed the height and rationale of the spaced pair.

Spot the difference! Left: the conventional, or Nimbus-Halliday, native B-format (or native 2D first-order ambisonic) array, which, top to bottom, comprises Y, W and X. Right: the revised version that I used, which, top to bottom, comprises Y, X and W. I used some thinner cables in the final version, not least as it made aligning easier when using shockmounts.

Taking the array outside: wind protection

With the pipe band test sessions being planned to determine whether any full recording session(s) for a CD should be recorded indoors or outdoors, the native B-format array needed to fit in a windshield. Inspired by ex-BBC sound recordist Roger Long’s experiment with a version of the Nimbus-Halliday array with the three mics (two MKH 30 and one MKH 20) all set vertically in a single suspension (the fig 8s side-by-side, and the omni in front), it is easy to rig the smaller MKH 8000 series mics in such a way as they fit into a normal blimp, which I duly tested (see photo below).

A very compact option for the native B-format array, fitting inside a standard windshield (in this case, a Rode blimp mk 1). I’d have been happy enough using it as shadowing effects and, indeed, any comb filtering arising from the non-coincidence on the horizontal plane are much exaggerated by the theoreticians that plague recording forums, but, given that I could fit the larger and nearer to ideal array into my DIY blimp, I decided against it for this project: but one to test more in the future perhaps as it is certainly much easier to manage in the field.

But given that use of the array in that set up means that the mics are not so well aligned in the horizontal plane, and that some will argue that acoustic shadowing results (always more theoretical than real), I thought it was just simpler and more consistent to use the same larger and more ideal array indoors and outdoors, taking advantage of my massive DIY blimp, originally built for LDC mics. A couple of welded additions by my ever-helpful friend Rob Moore, who built the original blimp basket, meant that the blimp was ready for my native B-format array.

And here’s the larger native B-format array inside my massive DIY blimp, originally built to accommodate an LDC mid-side pair for those occasions when extremely low self-noise is required: a few minor adaptations needed (thank goodness for its adaptable stainless steel construction).

Now by this point some readers may be wondering why I didn’t simply use an ambisonic mic. Well, other than not owning one and wanting to achieve a flexible approach with the excellent mics I am fortunate enough to own already, the key point is that the recording was not for surround purposes, but chiefly to determine the best approach for subsequent recording of a CD that is quite likely to involve a simpler approach. And, like many others, I have yet to be persuaded that the cheaper capsules in at least the more affordable ambisonic mics are in the same league as those of the MKH 8000 series mics. My biggest fear about the native B-format array was that the combination of mics – especially the combining of the omni and fig 8 – would fall well short of other MKH 8000 mics designed with a particular polar pattern. So at the planning stage I tested this by rigging an MKH 8020 omni and MKH 8030 fig 8 alongside an MKH 8040 cardioid, to compare virtual cardioid and actual cardioid mics. The consistency was remarkable, with the only audible difference to my ears being the slightly increased bass component of the virtual cardioid (not surprising: the MKH 8040 is no slouch in terms of bass, but it still lacks the bottom end of a pure pressure omni). So, happy with this key test, and with a workable native B-format rig, it was time to record: see part 2 of this blog post, for the first (i.e. indoor) recording session and results.

Top to bottom: MKH 8040 cardioid, MKH 8030 fig 8, and MKH 8020 omni. A simple test rig to compare the sound of the omni + fig 8 (mixed at 50:50 creating a cardioid) vs a purpose-built cardioid. This sort of virtual polar pattern creation is at the heart of the rig I was proposing, so thought a simple direct mono comparison like this a useful reality check before committing myself to recording with the native B-format array. The actual and virtual cardioids sound remarkably similar, although the additional bass response of the omni means that this is evident in the virtual cardioid: a high-pass filter could always reduce it if needed, but with the bass drum of the pipe band I thought this would be useful (as, indeed, proved the case). Changing the proportions of fig 8 and omni in the virtual mic means all polar patterns between fig 8 and omni can be created.

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A Few Thoughts on Field Recorders

July 15, 2024

Top to bottom: Sound Devices MixPre-3, Zoom F8n and Sound Devices 788T.

Introduction

As a bit of a change from microphones and windshields, I thought there might be a little value in some ramblings on the three recorders I use currently: not so much a review or test of any of them – none of them are new or even current products – but, rather, covering what I see as their different good (and bad) points and their uses to me. That is, for a mix of location music recording (mostly acoustic), sound effects, ambiences, and some dialogue recording for films (for YouTube). With luck this might be of interest to one or two others pondering these recorders or, indeed, their updated versions (for which many of the points remain pertinent): and on the latter, I’ll also cover why I haven’t yet found compelling reasons to buy the updated versions.

Perhaps first I should talk about sound quality. Much has been said and written about the different preamps (and, though less often discussed, ADCs) in the Sound Devices 788T vs the MixPre-series vs the Zoom F8/F8n/F8n Pro, mostly, but not always, placing them in that pecking order from top to bottom. Doubtless there is prejudice involved in some cases, but I am not going to quibble with highly experienced sound engineers with more finely-tuned hearing or, at least, listening skills: indeed, I would agree with them that the 788T has the edge, with little to choose between the MixPre-3 and the Zoom F8n. There are – I would hope – a lot of comparative recordings out there, but just to add to them, for a bit of fun I took the three recorders out with me this morning when taking advantage of a dry and fairly windless day (all too rare this summer in England) to have another go at a passing steam train recording for the current sound library project. It wasn’t a perfect recording (aeroplane noise yet again preventing a long intro from the train a mile or so off), but it will do for our purposes. The mics used were an MS pair (Sennheiser MKH 8040 and MKH 8030).

Set for recording a passing train with the three recorders: yes, I know a passive splitter may not be ideal, but there is no perfect way for such comparisons. The MixPre-3 was on the parallel (straight through) outputs of the Palmer PMS-02, and the F8n and the 788T were on the two transformer-isolated pairs of outputs.

Here’s what came past, working hard up the incline as it entered the cutting.

Make what you will of this field-recording example (and if really keen, download and do a randomized comparison, preferably listening to very short sections on repeat: I found the sections with the carriages passing, after the loudness of the loco, most revealing), what is indisputable is that there are differences, but they are subtle (for many) and for much use pale into insignificance compared to mic choices and mic placement.

A tiny three-channel (OK, now five-channel) recorder: the Sound Devices MixPre-3

The MixPre-3 was introduced back in spring 2017, along with its larger siblings – the MixPre-6 and the Mixpre-10. In 2018 the MixPre-3M, MixPre-6M and MixPre-10M were introduced: these were different versions of the recorders designed for music recording only, with such features as overdubbing, track laying, punch in/out, bounce, reverb and metronome. All these features were then made available to the original MixPre-series recorders via purchase of a plugin. In 2019 the MixPre-series ii recorders replaced the original models, with the main changes being the addition of 32-bit float recording to the series, internal timecode generation added to the smaller recorders (the MixPre-10T had it from the outset), and the addition of 192kHz recording to the MixPre-3 (its larger siblings already had it in the first series). The M series disappeared, with the Musician plugin continuing to be available as it is today.

I got my order in early and received my MixPre-3 in May 2017, so went through all the flurry of firmware updates that followed initial launch (indeed, reported on some required bug fixes and requested additional capabilities): the most useful refinement to firmware was, perhaps, in relation to mid-side recording, where decoding could be applied to the MS signal going to the LR mix only. Seven years on, I remain impressed by the recorder: aside from excellent sound quality and flexible set up, the key values for me are its diminutive size (less evident with its larger siblings), three P48 channels (so much handier than just two: think double mid- side, a stereo pair plus shotgun etc.), which can now (since 2023 with the +2 plugin) be used at the same time as its USB or aux inputs (think lav mics) to give five channels, and very straightforward operation. If the channel count has me covered, then this is the recorder I will take into the field when needing to travel light and compact for nature, ambience, effects and simple music recording. And with the unique (for a field recorder) ability of the MixPre-series to do overdubbing (recording up to 12 tracks: yes, even on the little MixPre-3 model), then this is the only recorder I have that will allow building up of a song on location sans laptop, musician by musician (think Playing for Change). By way of an example, back in the summer of 2018 I put the MixPre-3 with the new plugin to early use:

So why didn’t I replace the MixPre-3 with the later version, or, indeed, a larger version? Well, the latter is easy to answer: a larger version would lose the size advantage. That isn’t just the recorder, but also its power supply: the MixPre-3 can run three P48 mics for around 2.5hrs on rechargeable Eneloop Pro AAs, so, for my purposes, there’s no need for clunky external batteries (the battery sled allows changeover to spare sets of AAs in seconds). And the MixPre-3ii hasn’t attracted me by its virtue of its timecode generator (not something I use) or 32-bit float recording: even recording sound effects (such as the steam train recordings above) doesn’t give me level setting issues. Doubtless some find 32-bit float handy (e.g. for drop rigs for nature field recording, or for inexperienced recordists), but, personally, I see it as a solution to a problem I don’t have (without increasing mic input headroom – so many of these 32-bit recorders only have a 4dBu max mic input – and, also, introducing issues related to switching between ADCs). To each their own. Now there are some aspects of the MixPre-3 that I wouldn’t mind seeing improved: on the hardware design side, surely the three XLR inputs could have been moved to the one side, in so doing improving the position and form of the fiddly on-off switch; and on the software side, it would be useful if the gain/trim could be adjusted more finely than whole dBs, if the front knobs could be used for the 76dB of input gain/trim rather than as faders (or, in basic/custom mode, as combined gain/trim and faders), and if individual MS channels could have gain/trim adjusted despite being linked to allow for different sensitivity of mics. Minor quibbles, all of these.

Eight-channel recording: the Zoom F8n and the Sound Devices 788T

For larger counts than three P48 channels I used to use a mixing desk with ISO outputs to a laptop, but I really don’t like being dependent on a PC when tracking and, of course, this doesn’t lend itself so well to field recording. Looking for a field recorder with more channels, and having prior experience of the MixPre-3, means that the MixPre-10 was a serious contender. But a combination of factors – not least the massive jump in prices of these in the UK – made me consider the alternative of the Zoom F8n. By then (autumn 2022) the 32-bit Zoom F8n Pro had just been launched, so prices were very keen for the older model and, evidently, I wasn’t bothered by the 32-bit update. The form is more conventional, perhaps, than the MixPre-series, which is good for bag use (no trim/gain knob on the side), and the user interface and menus are all straightforward: the knobs and buttons are very small, but so are my hands, with the fiddliest being the on-off button again. I was pleasantly surprised by the sound quality, and don’t feel I am dropping down in that regard in any significant manner when upping the channel count has seen me use the F8n instead of the MixPre-3. An increase in channels has meant that rechargeable AAs are no longer feasible (and the eight of them are clunky to change compared to the four in the MixPre-3), so they are just there for back up: I power the recorder via its hirose socket with a L-mount battery (and Smallrig 3018 battery adapter plate). The two-card recording is a step up from the MixPre-3, providing redundancy, and the physical build quality is OK: excellent top and bottom aluminium plates, not quite matched by the front panel – a slight wobbliness to the fader knobs just doesn’t give reassurance of longevity. But solid enough for bag use. There are some great functions built in (e.g. holding down two channel buttons to link and unlink mic pairs), but I was disappointed that choosing the trim mode for the front knobs means that you lose use of a decent screen showing metering of individual tracks: so I am stuck with using those knobs as faders (when not really concerned about the LR mix). Amongst other limitations are the lack of word clock as, more latterly, I would like to be able to link recorders for higher channel counts (there is a lot disinformation out there, but, after pursuing this thoroughly, not least with Zoom, the F8/F8n/F8n Pro lacks the ability to provide the clocking for a slave unit and get sample-accurate sync); a lack of routing options, which include the inability to decode an MS linked pair to the LR mix whilst recording the M and S to the ISO tracks, and, of course, a lack of outputs; and some operational details such as back-lit buttons (you try operating the Zoom F8n in near darkness and see what I mean!). Additionally, the limiters aren’t perfect (they noticeably inject hiss).

A side on view of the three recorders: take away the XLR inputs on the two top recorders, and the gulf between them and the 788T becomes more obvious.

The subsequent F8n Pro addresses the limiter issue, but finding a recorder that doesn’t have the other limitations is not easy: other than the MixPre-10Tii (around £2000), which has word clock but doesn’t fix most of the other shortcomings, the current field recorder options are a huge step up in terms of cost: e.g. the Sound Devices 888 (8 channels of P48 preamps) at £9600, the Sound Devices Scorpio (16 channels of P48 preamps) at £12000, or the Sonosax SX-R4+ with the AD8+ preamp (giving 12 channels of P48 preamps) at £10000. And, also, these machines offer functionality beyond my modest needs, such as Dante. While happy with my MixPre-3, I remained unconvinced by the MixPre-10Tii and found myself increasingly hankering after the Sound Devices 788T. Introduced in 2008 (and discontinued in 2019), this was the precursor to the current 888, and retailed for around £7,300 (updated for inflation). The 788T features word clock, AES inputs, as much flexibility in routing as you could imagine, more outputs than the F8n, trim/gain control knobs, dual recording (triple if you like Firewire today!), illuminated buttons etc. and is built like a tank. After looking at the market for some time, I snaffled a beautifully cared for example from an LA sound mixer for about £1400 (inc. VAT and delivery), so that my most recently added recorder is also the oldest. Soundwise there is, as I said at the start of this post, not a lot in it: but at least I know I’m not shooting myself in the foot or under-serving the mics that I have. Functionality wise, there were a few great surprises I somehow missed: the fast headphone routing selection, line-inputs that can provide 48v phantom power (so useful when levels get really high with sensitive mics, taking the already healthy mic max input from +8dBu to +26dBu) and, not least of all, the fact that the main screen turns red when recording (and green when playing back: these options can be deselected if wanted) – an elegant way of reducing the cock-up factor. There’s an element of the 788T that appeals because of its amazing yet slightly old-school engineering (the sort of thing that means I might be tempted to buy a Nagra IV-S at a weak moment, if – unlikely – having surplus cash sloshing around!), but at the same time it stands up to the more modern MixPre-series and Zoom F8n/F8n Pro and has professional features and build-quality that are well above them. OK there’s a risk of failure with older electronic gear, but they remain repairable, and I’m not earning a crust recording production sound for Hollywood films.

The three recorders in record mode: you’ve just got to love that the 788T LCD screen turns red (and green for playback), and it alone has back-lit buttons to aid control in the dark. Add in the wonderful old-school Sound Devices LED level meters and the coloured-rings round the trim controls (something that the MixPre-series recorders use too), and you’ve got a lot of visual feedback on recording status and levels.

Conclusions

So where does this leave me? Above all, reassured that none of my recorders lack much in terms of sound quality: the 788T has a fantastic reputation in this regard and even I can hear this difference, and the other two are close enough for most purposes. And for use, well that’s the MixPre-3 for field recording with minimalist kit, such as for sound effects, or for anything that requires overdubbing; the 788T for music recording where I need a larger channel count; and the F8n where I need a larger channel count in the field, yet want a lighter recorder than the 788T, and also as a back-up to the 788T. Any of the three work fine for dialogue: usually I go with the MixPre-3 as my needs in that area are simple, so lightness wins out. Longer-term, a second 788T would give me 16 channels for ambitious projects, if needed: that could be borrowed or hired for those occasions if I don’t stumble across a real bargain over the years. If I do pick up a second 788T, doubtless the F8n will go: the weight advantage for high mic-count field recording is rather moot since, inevitably, that involves more mics, stands, cables and windshields (i.e. a whole lot of other gubbins). We all have different recording needs, but, just possibly, some of this may chime with somebody and give them food for thought.

An update (2/5/2025): a second 788T-SSD and a CL-8

It doesn’t really merit a new blog post, but, by way of an update on the previous post, this week I struck lucky on BB List and found a good condition 788T-SSD, dating from 2015 and used as back-up to a sound mixer’s main cart set up. He was retiring, and had the 788T for sale for £800 + VAT here in the UK, with a CL-8 (and various accessories too). It is unusual to find 788Ts in such good condition and priced reasonably in the UK. So it was an even better bargain than my first one, and 24 hrs later it had been delivered (I must say, BB List is an excellent intermediary) and my plan for a second 788T had come to speedy fruition (nice to be spared the hassle of importing/customs too). I was pleasantly surprised that linking the two recorders up for proper sample-accurate (word clock) synced 16 iso channels was quite so easy: just a C-Link cable (one came with my first 788T), and a couple of setting changes in menus (conveniently at the top of the long list of menu items on a 788T) and Bob’s was my uncle. Bought a new compact flash card and a faster 250Gb SSD (Samsung 870 Evo) to swap in as I did for the 788T I bought last year (Sound Devices technical support recommend SSD replacement every 3-5 years dependent upon usage, which is clearly preventative, but seems wise with a new (old) machine). Obviously, it is unlikely that I will use over eight channels for field recording, but for music location recording it will be very handy: only last week, I was caught out slightly with only eight channels when recording a bluegrass band in a pub, which wasn’t the sort of gig for a purist stereo-pair recording session. And it is a lot more viable for me than a £12k Sound Devices Scorpio! Going through the menus today, setting up the new recorder identically to my previous one was a great reminder of just how flexible and configurable the 788T really is: a thoroughly professional bit of kit, which sounds so good too.

Two 788T-SSD recorders running together for 16 channels with sample-accurate linking via C-Link. The lower unit has a CL-8 mixing control surface attached: easy selection of limiters, high-pass filters etc. as well as the large faders for the LR mix.

Turned around and upside down, here’s the rear view, showing the connection to the CL-8 (top) and the simple C-Link cable between the two recorders.

The ALT key on the side of the CL-8 lets you toggle between the three views: main, aux routing, and input settings.

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Field recording with a Blumlein pair of Rycote BD-10s

June 26, 2024

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.

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.

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Audio Gear

Rycote BD-10: the final production version

June 26, 2024

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

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Audio Gear

Sennheiser MKH 8030 part 4: comparing it to the MKH 30

May 7, 2024

Two mid-side pairs for size comparison: MKH 30 and MKH 50 (left) with MKH 8030 and MKH 8050 (right).

This is turning into something of a marathon, with the latest installment of the Sennheiser MKH 8030 fig 8 mic tests comprising a comparison with its older MKH counterpart: the MKH 30. The latter was introduced back in 1987 and is still in production: quite what Sennheiser’s plans are for the mic, now that the MKH 8030 is starting to appear in retailers, I simply do not know, but some of the other earlier MKH range have dropped out of production (MKH 20 omni and MKH 40 cardioid). Whether the MKH 30 continues to be made for years or not, recordists will wonder: just how does the new fig 8 compare? As with all the MKH 8000 series mics there are the obvious physical differences of size; the new series being modular; and the earlier range having built-in switchable high-pass filters and pre-attenuation (vs this only being available via the additional MZF 8000 module – now just updated to the MZF 8000 II). And then there is the extended high-frequency response of the MKH 8000 mics. But just how different do the two fig 8 mics sound? I was certainly interested in this question, and have been receiving queries from others similarly wondering, so armed with an MKH 30 and, to allow some MS comparisons, an MKH 50 (still in production, by the way) sent by the folks at Sennheiser, I set to for some comparisons.

The sound of silence

First off to compare is the sound of the two mics recording nothing: their self-noise. Both are specified as 13dBa, but self-noise rarely sounds the same between different makes or even ranges of mics and with the known very different frequency response above 20kHz, there was every reason to suspect there might be subtle differences as, indeed, there are between the other MKH 8000 polar patterns and their older MKH counterparts. So into the airing cupboard, under duvets and towels, went the mics and off went the electricity for my usual home-brewed and very much not laboratory conditions for comparing self-noise. As for the self-noise tests in part 1 of the MKH 8030 tests, I used a 100Hz high-pass filter since it was impossible to keep out the very low frequencies.

Here are the spectrum analyzer visualizations of the noise, with gain cranked up:

MKH 8030 with 100Hz high-pass filter: scale 100Hz to 48kHz.

MKH 30 with 100Hz high-pass filter: scale 100Hz to 48kHz.

As expected, the self-noise looks wildy different, but, of course, most of this is the increased self-noise in the MKH 8030 over 20kHz (i.e. above human hearing). In the audible part of the spectrum, the two are pretty comparable, although the gentle dip between 1kHz and 6kHz is a little deeper (by a couple of dB) with the MKH 30, which translates to the self-noise of the MKH 8030 being fractionally more noticeable. But we are splitting hairs here: both mics have remarkably low-self noise for SDC fig 8s and there is nothing of concern with the new design vs the older one on this front.

Bat recording at dusk in Guestwick Church.

Bats in the belfry…or not

One of the distinctive features of the MKH 8000 series is, indeed, the extended frequency range. You can see this in spectrograms of many a recording where frequencies above 20kHz are present: the specs cite a 50kHz upper limit vs 20kHz for the MKH 30. Taking this to extremes, I went with Norfolk-based ecologist, Danny Cotgrove, to Guestwick Church at dusk, comparing the MKH 8050/8030 and MKH 50/30 mics: obviously an unfair comparison, but it was an interesting evening nonetheless. I was particularly impressed by seeing Danny’s Batlogger M2 in action (evidently the right tool for the job), but that’s another story. There weren’t a lot (a ‘cauldron’?) of bats in action, but just the odd one: common pipistrelles and some Myotis bats (probably Natterer’s bats), apparently. Here are a few short clips, slowed down to 25%.

The bats are much clearer in the MKH 8050/8030 MS pair than in the MKH 50/30 pair, as expected, but the self-noise of the MKH 8000 mics at such high frequencies is distracting. Obviously, to get usable audio from such quiet ultrasonic sounds requires some hiss removal, so here is a very quick and dirty example using RX De-noise:

And here are the spectrograms for the two fig 8 mics:

Spectrograms of a clip of the bat recordings (as originally recorded), with MKH 8030 (left) and MKH 30 (right): the vertical axis extends to 96kHz, and the clearly visible (red) spikes of the bat sounds in the upper halves of the spectrograms range from around 46kHz to 76kHz.

Up in the belfry of Norwich Cathedral risking my eardrums…again.

At face value, the bat recording example might seem as if it leads to a dismal conclusion: i.e. the MKH 8030 has much higher frequency capability than the MKH 30, but the price of raised self-noise is too high to pay. But bear with me. With a touch of irony, I headed off to the cathedral belfry, not for more bats but for a (very) healthy signal of an audible sound with extended high frequency overtones: the bells, the bells! The spectrograms show that the sound extends above 48kHz, but of more use are the sound files.

Here we have the original unmodified (mono) recordings with the individual fig 8 mics:

And here we have the same two clips slowed down to 25% (just as I did for the bat recordings), as if playing around for sound design: reassuringly there is no distracting self-noise – a consequence of a healthy sound signal – and there is no need for noise removal.

So, yes, the MKH 8030, like its siblings in the same series, has extended high-frequency that can be useful and is something that the MKH 30 and its siblings don’t offer to this degree, but, with quiet signals, it will need much care and some de-noising. Whether or not this capability matters to the sound recordist is a different thing altogether: for many, if not most, a frequency response over 20kHz is simply not needed.

It’s all about that bass

Down at the other end of the frequency spectrum the specs for the two fig 8 suggest that the MKH 8030 goes a bit lower: the frequency response graph of the MKH 30 cuts off at 40Hz, though, so it is hard to tell from this how it compares with the MKH 8030 below this. Turning to my quick and dirty low-frequency source, I stuck the mics by the exhaust pipe of an idling car engine, and this showed that the MKH 8030 does indeed have more low end that its older counterpart.

Here are the sound files:

And here are the spectrum analyzer visualizations of the exhaust recordings:

The most distinct feature is the level of the fundamental (26.4Hz), which is c.4.5dB louder with the MKH 8030 vs the MKH 30. This is not to say that the MKH 8030 oddly emphasizes bass: as we saw in part 1 of the MKH 8030 tests, similar tests with another car exhaust saw the MKH 8040 measure 9dB more than the MKH 8030 at the 22.5Hz fundamental. Now, just as with the high-frequency extended range, some may not find the increased low end of the MKH 8030 vs the MKH 30 especially useful, but I suspect many more will, for music recording and bass-heavy ambiences and sound effects amongst other things. I’m certainly one of the ones who is glad to have a bit better low-frequency performance. And if you don’t want it, its easy to roll off with a high-pass filter in your mixer/recorder or via the MZF 8000 ii filter module.

I suspect this view is getting rather familiar to some readers of this blog…

In the field

The robust and, above all, humidity-resistant nature of the RF-based MKH mics has made them favourites for recording in the field, be that production sound or field recording, so I moved on to record some ambiences. As usual, nothing very adventurous: you don’t need a long-haul flight and a rare species to test a mic in the field (though doubtless a rain forest would provide some nice humidity), so, as I have done so many times before, I ventured a few yards further down my drive from the car exhaust test to record the sounds of early May in my quiet Norfolk village street. Sorry if you are getting bored of listening to my village street, but cheer yourself up with the thought of how environmentally friendly this is! And it always gives a good mixture of sounds: birdsong, passing cars, the odd sound of a distant shotgun (or is it a bird-scarer?), and whatever the neighbours are up to: a bit of landscape gardening this time.

There are two sets of recordings: first off, we have the two fig 8s together, rigged with back-to-back clips in a single Rycote Cyclone, and facing the road;

Then, second, we have two separate windshields each containing a mid-side pair with each fig 8 paired with its super-cardioid sibling. Obviously the different qualities of the two mid-mics comes into play, but as an MS side mic is how most field recordists use the MKH 30 and how most will use the new MKH 8030.

Luke Chapman in his workshop, playing a bit of guitar into an MKH 30 and MKH 8030.

Down in the workshop

Moving inside again for some musical tests, I tootled down the back lanes to the workshop of woodcarver and musician Luke Chapman. Luke was happy to put down his chainsaw (well, actually he was re-spraying his Land Rover chassis when I arrived) to oblige again with some guitar playing, and the sets of recordings comprise mono recordings with the two fig 8s (which I rigged end-to-end, pointing at the twelfth fret from about 600mm/2ft away) and then mid-side recordings with the MKH 8050/8030 and MKH 50/30 pairs, a little further back (to get a bit more ambience into the recording: you can really hear the rooks outside trying to join in). There has been no processing (compression, equalization, addition of reverb etc.) of the recorded sound. The mono recordings with just the two fig 8 mics aimed towards the sound source are perhaps the most informative, although, again, the MS pairs show how the two mics sound with one of their respective siblings as the mid mic. I’m sure some will hear (or at least imagine they hear!) significant differences, but, to me at least, the two fig 8s sound remarkably similar.

Here are the two recordings of the fig 8s on their own:

And here are the recordings of the two MS pairs:

And here’s a video of the guitar test recordings – both the mono comparisons of the two fig 8s, and then the two mid-side rigs – cutting from one mic/pair to the other.

Conclusions

These few tests just skim the surface of comparisons between the MKH 30 and MKH 8030. With the other polar patterns of the two MKH ranges of mics, there have been recordists who prefer one to the other: or one vs its equivalent for a particular purpose. Evidently there are some subtle nuances and preferences, with these varying in relation to a wide gamut of sound sources, that are beyond the scope of the necessarily simple tests here: such discerning recordists will want to get both mics in their hands to compare them in their typical uses. But with that caveat, my experience of using the two mics is that the MKH 8030 occupies a similar position to the other MKH 8000 mics compared to their equivalents in the older MKH series: as such it lives up to the well-deserved reputation of the MKH 30. Just as with the other MKH 8000 series mics, it doesn’t render the older MKH fig 8 redundant: far from it. If you need a very low noise SDC fig 8 with demonstrable ability in high humidity and that sounds top class, then both of the Sennheiser fig 8s are likely to be at the top of your list: if you also want a very small SDC and one where there is a full range of mics in the same series currently in production, then, obviously, your choice out of the two will be the MKH 8030.

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