What’s in my bag

Here’s my bag- every sound recordist’s is a bit different and I thought I’d give you a tour:


Logically, I’ll start in the middle.  The mixer’s essentially the ‘heart’ of a sound recordist’s kit- with it the recordist can control the level of signals, so that a healthy signal to noise can be maintained but the signal is not distorted.  It also has analogue limiters which will compress the signal during peaks (such as shouting)- this is one of the main differences between mixers built for broadcast and those built for music (in addition to build, powering options and outputs)

Each of the three larger knobs control the level of each signal being sent to the mix, whilst the gain knobs set how much each signal is amplified.  LF cut is a filter which reduces the amount of lower frequencies present in the signal (which can be increased by microphones being placed close to the subject), this can also cut out some noise from the microphone being moved around and wind noise.

It will also power microphones and amplify their signals

Mixer ‘input side’:

Here’s a view from the left hand side of the bag.  Here the inputs are going into the mixer on the left.  The cable at the top goes to the boom microphone, whilst the cables with red and green bands come from a radio microphone receiver.  The thinner red cables provide power and the black cable going into the recorder on the right comes from the mixer’s digital output

Mixer ‘output side’

This particular mixer (Sonosax SX-M32) has ‘direct outputs’, which means each of the amplified microphone signals can be sent out before they are mixed.  This can give post production more options. Here the top cable, with the darker red ring sends a mix to the recorder and the other three send pre-fader direct outputs. The smaller ‘mono out’ usually goes to a radio transmitter, sending out a 1 channel mix.  There are also a couple of other connectors out of view which include one for a sending a 2 channels to a camera and receiving one back so that I can hear what is being recorded to camera, when not using a separate recorder, and a smaller one which sends the mix digitally to the recorder.


This is the box at the bottom of the main picture.  Although it is also possible to plug microphones directly into this particular model, the quality and flexibility is not as good as using a separate mixer (there are a few recorders becoming available which can also operate as a mixer).  This one (Edirol R-44) can record 4 channels of audio, as digital .wav files.   Some recorders also have timecode generators which can be synchronised with cameras, making it faster to synchronise video and audio in post production. I also own a 2 channel recorder with timecode facility


There are a number of situations where it is impossible, or extremely difficult to capture quality audio without using cables.   Although the most expensive and advanced wireless systems are not as high quality or reliable as a cable, they’re close- and allow microphones to be placed where they couldn’t without wires.

This particular box (Wisycom MCR42) actually has 4 receivers inside, 2 per transmiter- selecting the one with the strongest signal.  It also has emulation modes for other brands of receiver (Sennheiser and Audio Limited) and a very wide bandwidth, making it suitable for international use

Radios can also be used for sending signals, such as an feed to a director, boom operator, script supervisor or camera to aid with sync (or to send a timecode signal).  There’s also a transmitter for this purpose on the right and second receiver on the left (single channel) for a third radio mic.


Inside the pocket at the back of the bag is the battery and distributor

From here the battery power is split between the mixer, recorder and 2 channel radio  receiver.  Here is the whole bag opened up:

Here you can see the red cables running to the recorder, mixer and radio receiver in the front pouch

Computers for Production Recording

In almost all production recording systems some kind of field recorder is used.  In most of these cases they’re actually a very specialised computer running a cut down operating system (usually a Linux kernel or Windows Embedded variant) with custom software.

For example, I’ve found my Tascam HD-P2 runs Windows CE (it’s mentioned in the version 1.05 release notes).  As a you start to think *OMFG my recorder will BSOD on me*, a lot of the problems with Windows (and other OS) is when things get changed, and systems have to deal with this.  Usually with embedded systems this isn’t the case, they’re ‘sealed units’ and run all sorts of systems which cannot tolerate failure like aircraft autopilot systems and industrial automation systems.

Why not run a specialised computer for recording purposes? It’ll be much cheaper, right?

One of the main issues is software.  Although there are quite a few programs for multichannel audio recording and mixing, most do a lot of things you don’t need for production recording (which means more to go wrong) and some don’t do some things you do need (metadata editing and Time Code input).

The best course of action would be to use a piece of software designed for this purpose, AFAIK there are three (prices include VAT):

Boom Recorder (Mac OSX only) £175
Metacorder (Mac OSX only) £1314
SADiE MTR (Windows only, with SADiE Hardware) £4100 with LRX2

You also need an interface to get the audio into the computer.  Here’s a list of those which I’ve found which have at least 8 inputs and a DSP routing system, can be powered by DC in the field

Interface Price Weight (kg) Dimensions (mm) Power Consumption (W)
RME FF UC (USB) 722.73 1.5 218x44x155 13
RME FF UCX (USB/FW) 958.26 1.5 218x44x155 13
MOTU Traveler mk3 (FW) 589 1.73 375x44x229 ?
Metric Halo 2882 (FW) 1215 2 343x44x279 8
Sadie LRX2 (USB) 4100 6 330x65x423 50

Now you’ll need a computer to run it.  I initially had ideas of very small industrial machines with no moving parts and Atom/AMD Fusion CPUs.  These would work fine with the SADiE system (in face any machine with a hard drive fast enough should, as the LRX does the heavy lifting), but I’m not too sure about running OSX on them.  In addition to this the RME USB interfaces don’t work too well with Atom machines (and haven’t been tested with the AMD chips).

Having a look round for a small computer which will run off DC power, not have an atom processor and run OSX it looks like you’re looking at a Mac or a going for a ‘hackintosh’ job (installing OSX on an non-apple x86 machine) on a similarly sized ‘ultrabook’ (which would cost around the same for the base machine).  Prices are given with 15% discount (either as a refurb or through a number of discount schemes, education etc). I’ve discounted the low end Macbook air as I don’t think 2GB memory will cut it:

Computer Price (£) Battery life (Whr) Power consumption (W) Weight (kg)
Display off Display on
Macbook Air 11” i5 4GB 128GB 850 35 4.2 9 1.06
Macbook Air 11” i7 4GB 128GB 970 35 4.2 9 1.06
Macbook Pro 13” i7 128GB SSD 1172 63.5 7.2 12.7 2

Another thing which will need to be added to the system is a TCXO clock, if time code sync is required (clock on LRX2 will probably suffice).  Here are some options:

Denecke SB3 £384
Timecode Buddy Master £810.00
Ambient ACL203 £690

In order to use firewire interfaces with the Macbook air, you need some kind of thunderbolt adapter.  The cheapest current method is (this means it’s actually cheaper to use an RME FF UC with Macbook Air):

Sonnet thunderbolt to expresscard 123.60
Thunderbolt cable 39
Expresscard to FW 16.78


In order to create mixes you’ll also need some kind of mixer or control surface.  If you’re already running a mixer in front of your recorder you can probably make do.  For drama/ cart based setups the only option I can see which runs from DC power is the Avid Artist Mix (formerly Euphonix MC mix) at £1000.  On the other end of the scale there are a few USB powered things with knobs/faders on from Korg and Akai, which may break from just looking at them

Control Surface  Cost (£) Weight (kg) Dimensions (mm)
Avid / Euphonix Artist Mix 1000 2.2 238x30x420
Mackie MCU Pro 1000 7.6 419x119x423

Bag setups *may* be feasible by putting the laptop at the bottom of the bag, the interface where the recorder would normally be and using a small touchscreen monitor for control: eg Lilliput 669GL

Finally here’s a few example packages you could put together here  The LRX2 price is taking into account using an existing laptop, adding the 16mic pre card and 25% discount for part ex with old SADiE kit (can be found on ebay for buttons):

Price Weight (kg) Power Consumption (W)
Cheap (MBA+FFUC+Monitor+Denecke+BR) 2287.73 2.56 17.2
Drama (MBAi7+FFUCX+Avid+Denecke+BR) 3487.26 4.76 17.2
Lo Power (MBAi7+MH2882+Denecke+BR) 2941.03 3.06 12.2
SADiE LRX2 (USB) 4500 8 50
Sound Devices 788T + CL9 6953 3.8 16


Here’s a comparison of different systems taking into account cost, weight and power consumption.  I haven’t added the monitor power consumption- it’s around 8W, assuming you may also use one with a  788T system. I believe the LRX2 can actually display sync video on screen.  I also don’t know the power consumption of the Avid Artist mix

Last Christmas Variations

Here’s something I made the other day after getting a bit distracted while fixing up a slightly faulty Yamaha SHS10 keytar.  It’s all done with by playing the demo (Last Christmas by Wham!) and making different connections on the circuit board

[soundcloud url=”http://api.soundcloud.com/playlists/1647994″ params=”auto_play=false&show_artwork=true&color=ff0004″ width=”100%” height=”450″ iframe=”true” /]

I’ve been told that Stewart Walden’s (now Keith) Cucumber Sandwich is played on a Casio SA10, and features ‘Wake Me Up, Before you Go-Go’

If anyone else knows of any other keyboards featuring George Michael’s work, please enlighten me




I’ve just made a new addition to my self-made power distribution system- a small voltmeter (the display with the numbers on the left, by the recorder).  This allows me to see exactly how much battery power I have left  They’re available from a number of sellers in China on ebay

I just soldered the red and green wires (+ power and voltage reading point) to the positive pin and black to 0V) on my power distribution box and it all works

Here’s the distribution box and battery:

It’s essentially a load of locking DC connectors wired in parallel


Selling Stuff

I’ve had a rummage through the cupboards and I’m looking to get rid of a few bits I rarely use, or have meant to get fixed and haven’t.  Open to offers on all

Doepfer Regelwerk Discontinued MIDI/CV sequencer/fader controller SOLD


Yamaha DX7S 80’s classic with a few tweaks.  New internal battery fitted £200

Panasonic NV-MX300 small 3CCD DV camcorder- doesn’t play nicely over FW with MS Windows (firmware bug) £200 SOLD

Commodore MK10 mini-key MIDI keyboard £15
Really light midi controller keyboard, great with small synths/samplers without keyboards.  And gets bonus retro points for saying Commodore on

Sennheiser ME3-ew Headset mic £50
Part of the Sennheiser ew135 system, as recommended by Alan Partridge.  Needs 5V plug in power.

Behringer Ultra DI800 8 way DI box £50 SOLD

Roland D-110 multitimbral sound module £40
Volume knob missing

Roland SP-404 (broken, won’t boot up) sampler good condition £50

AKG C535EB Condenser mic (broken, no signal + paint come off) Nice when working… £30


Mackie 1604 rackmount rails, unused £15 SOLD

Clocker / Counter

Here’s a video of me performing an adapted version of Alvin Lucier’s Clocker at Bang the Bore X: Zone of Alienation

Instead of using a clock, we substituted it for a Geiger-Muller counter and radioactive source: Thorium 232.

Equipment used:

DIY Galvanic skin response sensor
Tapco Blend 6 Mixer
Roland SDE-3000 Digital delay (has control voltage input)
Coutryman B3 Microphone (to pick up the counter’s speaker output)



Radio microphone comparisons

I’ve done a comparison of the various models of (reasonably) high end radio microphones available in the UK which will work with DC powering.  As a number of them work with 2 transmitters to 1 receiver, I’ve also made a cost comparison (most competetive I could find, including VAT) of 2 sets and put in the weight of the transmitters.

Transmission systems:

Analogue: Up until recently all radio microphones were analogue.  They use a compander circuit which compressed the audio signal on transmission and expands it in at the receiver.  The circuits need to be compatible on each end to match

Digital Hybrid:  Here a digital signal processor at both ends of the system looks at the incoming analogue signal coming in an compares it to a predictor algorithm, and sends any difference from this to the receiver as an analogue signal which will recreate the original.  They can also program in different compander algorithms, which can mean the receivers can work with other equipment.  The conversion and processing adds some latency (time in ms)

Digital:   With ‘pure’ digital systems, the signal is converted into a digital signal and compressed using a high-speed codec (like mp3 but faster to read/write and maybe better quality) before transmission.  This means they don’t use a compander at all and there are less analogue to digital conversions than with hybrid systems.  The conversion processes also add latency


This effectively means that the receiver has two goes at picking up the signal and picks the strongest, however the point where this happens depends on the receiver design (all receivers here have diversity in some form).  “True” diversity requires two separate receiver circuits, whereas antenna diversity switches between the signals from the two antennae.  In analogue systems it is often audible when switching between antennae, although I’m not certain with digital systems.  Also only two systems have true diversity in a dual channel receiver (4 receiver circuits), the Wisycom and Audio ltd EN2.


Although UK Channel 38, which we’re all supposed to be using next year is only 8MHz from 606-614Mhz, if you’re doing any work abroad or getting site-specific licenses you may have to be more flexible (or if things like ‘white-space’ devices start popping up).  The Wisycom, Sennheiser and  Audio Wireless systems have larger bandwidths (at a cost)


Some of the systems have methods of remotely monitoring and/or controlling the receivers, and a number of them require buying a separate add-on or device.  Both digital systems will allow full control of transmitters from the receiver and the Sony system will allow you to name transmitters. The other systems require things like infra-red remote controls (which may not penetrate costume).  The Lectrosonics system uses audio tones through the attached microphone.


A few of the digital systems will allow digital output to recorders/cameras which have it, which can free up some more channels and reduce conversion processes.  Only the Sony system has word clock, so can be used in multiple instances in a system without sample rate converters.


One of the main differences between the Zaxcom system and the others is that it can do some things which would require additional hardware.  The transmitters also act as 2.4GHz receivers so talkback and timecode transmission can be used with them if the receiver has the IFB option (or from a Zaxcom recorder).  Finally, some of the transmitters have recording facilities (for backup purposes) and will transmit in stereo.

Also, finally- if you are buying radio mics in the UK, make sure they’re Channel 38 compatible (606-614MHz), the current band, Channel 69 (854-863MHz) is probably going to be sold to mobile phone companies after the olympics.  Also the (otherwise lovely looking) Lectrosonics D4 isn’t available here as it uses a current GSM mobile band, so it won’t work.

System (RX/TX) Transmission system Diversity RX weight Dimensions (mm) Bandwidth (CH38) Remote Output RX cost TX cost Price: 2xTX+2xRX Notes
Lectrosonics SR / SMB Digital Hybrid
Antenna (1ch true) 195g 68x89x18 25.5MHz All with RM (£462). Or phone app (£30) Analogue £1,650.00 £1,170.00 £3,990.00 Compatible with Senn HiDyn+, Shure, Audio ltd tx. Scan function
Lectrosonics UCR411a  / SMB Digital Hybrid
True (1ch) 330g 82x120x31 25.5MHz All with RM (£462). Or phone app (£30) Analogue £1,250 £1,170.00 £4,840.00 Compatible with Senn HiDyn+, Shure, Audio ltd tx. Scan function. Front end tracking
Zaxcom QRX100 / TRX900LT Digital (3.6ms) Antenna
(1ch true)
170g 83x133x32 30MHz All + IFB/TC – IFB board
needed £590 (2.4GHz)
Analogue+ AES £1692
(£2282 w/IFB)
£1,149.60 £3990 / £4580 Stereo transmission. IFB allows
2 way audio, TC, recording option on TX. Camera link TX. Scan
Wisycom MCR42 / MTP30 Analogue with digital expander
TRUE (2ch) 180g 68x115x18 240MHz All (IR), (battery on emulations) Analogue+ AES £2,548.00 £1,978.00 £6,504.00 Compatible with Senn HiDyn+, HDX, Audio ltd  and most other analogue systems. Scan. 10mW circulator on TX. Moveable filters
Sony DWR-S02D / DWT-B01 Digital
Antenna 280g 88x119x31.3 72MHz
/ 66MHz (tx)
All + metadata (2.4GHz) Analogue + AES
(+Word Clock)
£1,901.33 £1,278.84 £4,457.00 USB keyboard input. 7V power only. Scan, full remote control of TX from RX. TX power goes down to 1mW
Audio Ltd EN2 Analogue TRUE (2ch) 196g 63x139x20 24MHz Analogue whole kit £2,753.00 LCD on side. Scan. mini TX avalable
Sennheiser EK3241B / SK5212-II Analogue True (1ch) 200g (x2) 74x120x28 36MHz RX,
184MHz TX
Battery (RF) Analogue £1277 (x2) £1,996.00 £6,546.00 RX can be reprogrammed within a 240MHz block. 10mW circulator on TX
Micron SDR550 / TX700 Analogue True (1ch) 200g (x2) 63x121x22 32MHz Analogue £1618 (x2) whole kit £3,236.00 no LCD display, New tiny TX
Audio limited DX2040 / miniTX Analogue True (1ch) 250g (x2) 64x147x20 24MHz All on separate IR device Analogue £1716 (x2) £960.00 £5,352.00 display on switchIR only (£50). Scan on palmpilot only. TX is Tiny
Audio Wireless Analogue True (1ch) 200g (x2) 62x114x20 32/64/120MHz Analogue £1275/£1700
/£2150 (x2)
whole kit £2750/£3400
LCD on side


I’m really excited about a job I’ve got coming up, I’m off to France for a week to follow Team Strakka around for the Le Mans 24 hour.  Not only is it going to be taxing on me, especially for the race- but also for powering my kit.  So far I’ve managed to get by on AA batteries (bulk bought duracell procell from ebay or Kingsland waste market in Dalston), but it’s really not going to be practical for a week.

First of all I’ve found a way of getting a bit more from the AA’s- you can buy chargers which will get a few more goes out of alkaline batteries.  I’ve just had a couple of these arrive and they’ve got some of the spent batteries in them at the moment.  Both the mixer and recorder seem to give up when they get down to around 1.3V.  They’ll still be useful for the radio mics and as a backup.

For a while I’ve used a cheapo chinese Li-Ion 12v battery “6800mAh” designed for CCTV (with a polarity reverse cable) which’ll get a couple of hours out of the recorder. I think the 6800mAh quoted might be for something like 5V though (or just lies).  The connector is jut a 2.1mm barrel connector though so I really don’t trust it.

From having a look at what was available my choices were:

7.2V DVcam batteries- small, long lasting (although the equipment may drain more at a lower voltage, depending on the regulator), locking connector. Reasonable price

9V/12V consumer DVD player/CCTV batteries.  Cheap. Non Locking connector

Professional 14.4V NP1/V lock/gold mount etc. Big. Locking connectors.  Expensive

Unfortunately 7.2V wasn’t enough to power my recorder (even though it only gets 6V on AA’s), so that was out.  The consumer stuff would involve risky connectors and look cheap so I’ll see if I can do pro stuff.

I also found a full length NP1 doesn’t fit in my bag (I’ve got a couple of old ones).  The V-lock batteries etc were even more expensive and wider so that may not have been an option either.

Fortunately Hawk-Woods make a ‘Stubby’ NP1 style battery, the NP35 which will fit.  Shopped round a bit and got them for £70 each.  However they’re Li-Ion and my (broken) NP1 charger only recharges Ni-Cd and NIMH.

So, new charger.  They can get really expensive (up to £700…and they just recharge batteries?!?). Got a no-name chinese one off ebay (*hope it works*) for £80 which will recharge 4 batteries after just missing out on a 2nd hand PAG.

Finally to hook it up to my kit.  I’ve just bought a Hawk-woods NP1  shoe (rather than the full regulated distro) and I’m going to sort out a custom cable for it.


Large Feedback Instrument #2

From last time I’ve now managed to get some new IDC headers to replace the broken ones, so went about reconstructing the ribbon cable.

I also gave up on the idea of getting an A-gauge patchbay and soldered in the aux sends to the back of a 96way bantam patchbay as shown here:

as there was only one 0V reference I had to get a wire and bridge it across all the other connections.

I also wired in 8 jacks to feed back the signal into the mixers inputs.  I decided to leave the connections open too, although I considered having them normalled (see this article for patchbay configurations) which would be mental (all signals would be feeding back all the time).

Now to fire it up again and see if there is audio…

Unfortunately I’ve only got 2 bantam patch leads (this might get expensive to remedy). But running 2 channels and 2 auxes it sounds like this (go to the end for animal sounds):


Large Feedback Instrument: Test 1 by richard-thomas

DIY acoustic equalizers

In February I recorded a fantastic concert (review from The Watchful Ear) put on by Bang the Bore in Southampton.  It was located in the Castle Vaults, under the town centre and consisted of a performance of Alvin Lucier’s classic, I am sitting in a room and a top form set from John Butcher who does things with a saxophone which must be heard to be believed.

As a large part of what was going on in this gig was reacting to the space (John Butcher has an ongoing ‘Resonant Spaces‘ project), I thought I’d try and record as much of the room without it getting too muddy.

Omnidirectional microphones, pickup the most room sound but need to be placed within the critical distance (closer than the with directional microphones) to receive more of the direct sound from the performer rather than reflected sound from the walls of the room.  I was looking at recording outside the critical distance, in the diffuse field (where there is more sound reflected from the room) so needed to improve the directivity of my microphones but retain the flat frequency response down to low frequencies that the omni’s have.

You can do some of this using EQ on a mixer.  Alternatively you can affect what happens to the sound before it gets to the microphone by creating a reflective baffle around the microphone, which I intended on doing.  DPA already make these for their microphones, but they’re £75 each (ow!) and don’t fit my AKG’s.  So went out to the local shops in search of foam balls…

I came back with a pair of ‘Dog Balls’ from “Magic Prices at Just Jeff’s” (yes, it’s really called that) and an apple corer.  Total cost was under £3. And lighter than a mixer 🙂

Unfortunately the apple corer wasn’t the best tool for the job:

however (with some pain and awkwardness) did get through the balls *ahem*.

and managed to squeeze a microphone through:

although they did look a bit silly they did do the job, however the room wasn’t as reverberant as I expected.

I’ll see what’s happening with the recording- if it gets put up somewhere I’ll add a link