Audio Interfaces as Location Mixers 2: Motu AVB Midi to OSC

Earlier this year I made a post about the theoretical use of audio interfaces as digital mixers.  Since then I’ve got some toys and the experiments have begun:

Motu 8D

I ended up getting a good deal on 2 of these interfaces.  They each have 8 channels of AES3 audio in and out with sample rate conversion, although some of the connections are 75ohm RCA for consumer SP/DIF.   They are also happy with a variable voltage range and are happy with reversed polarity on the DC input (even though the plug says 15V centre positive).  The AVB connection allows them to link together and address multiple channels from one interface, essentially making a modular interface with all sorts of connections.  Together they have 16 inputs and outputs.

Control Surface

I started off here running a Keith McMillen K-Mix, however it just runs standard midi control change and note outputs.  These are easy to deal with and re-route, however I came across some issues with resolution which were solved by using a control surface that runs the Mackie Control Universal protocol (MCU).  The cheapest one I could find was an iCon Platform M.

Lost in Translation

The problem with the MOTU interfaces in this instance was that they used a nice control protocol for computers to talk to each other, but not control surface hardware- they’re designed the interface with the view that it’s used on an ipad or similar.  They use Open Sound Control to communicate (documentation here), so there needs to be a way of converting midi commands to this.  It’s also one way- the interface doesn’t send any data back.  So, I needed a way of translating midi commands to OSC.

Pure Data

After looking at a few solutions, and realising I can’t program properly- it dawned on me that I could use Pure Data.  It’s an open source graphical programming language (similar to the proprietary Max/MSP) and I’d used it before on various music performance projects.  It would also run on a raspberry pi– so could have a low power dedicated computer to do the translation work.  I found it was actually pretty straightforward to get the midi in and the OSC out, however came across a few snags…

Linear faders

This is one of those terms where everything gets confusing.  Yes, linear faders can mean they’re in a straight line- rather than rotary faders, which you turn.  The potentiometers, however need to be logarithmic- every 3dB of attenuation is a halving of voltage.  In most midi applications this would normally be done at the software end, but here it’s just a number being fed in.  In order to do this a bit of mathematical transformation of the data was required and the higher resolution of the faders really helped in MCU (they’re used as pitch bend controls on each channel).


In order to run 16 channels from an 8 channel controller I decided (possibly foolishly) to create a second layer on the PD patch and send back data to the control surface.  It works, however the mute and solo buttons unexpectedly turned out to be a headache!


Wot, no Dante?

I had a look and I couldn’t find and DC powered interfaces with a Dante connection and a mix engine.  Best option I can think of is to use a MADI interface (such as a MOTU M64 or RME Madiface Pro) and a Directout or Ferrofish Verto series converter


I haven’t put a dedicated talkback control in yet, but should be a case of pressing a button to open a fader.  There is a dedicated talkback button on the newer Motu 828es, however- although it only has mains power

I Want This

If you want to have a go with it, please feel free to get in touch.  I can’t offer any kind of warranty or technical support at the moment- it’s just a thing I made.  It should hopefully work with any of the Motu AVB interfaces and midi controllers with MCU emulation.  It requires pd-extended 0.43-4 to run

Radial Catapult CAT5 Extender

I don’t normally do reviews per-se, but I thought this was a particularly useful bit of equipment and it may not be obvious at first glance why the Radial Catapult is so useful. So much so, I didn’t realise its usefulness until buying the wrong boxes…

Radial Catapult TX4

Standard Analogue over CAT5

I initially bought just the standard TX and RX boxes which don’t have any transformers.  After doing some work making my own analogue to CAT5 adapters before,  I found they weren’t rugged enough.  Also I’d found that the Neutrik CAT6 connectors weren’t compatible with their standard ethercon connectors.  These were obviously well made in pretty chunky steel cases.  As CAT5 is 100ohm, it’s also ‘close enough for jazz’ to 110ohm and is able to run long distance AES3 digital signals. 48V phantom power can be provided as long as shielded CAT5 cable is used.


They also have the advantage of working like a  4 way ‘Y cable’ providing a passive split of the signal.  As most of my kit is battery powered a lot of the time, I didn’t see a need to get the transformer versions.  Everything in them is wired in parallel, so the same signals are split across both XLR connectors opposite from one another and the same signal comes out of both CAT5 sockets.  There’s also all passive boxes, so no power supplies are needed, however any splits will incur a 3dB loss in signal.

The ‘TX’ boxes have 4x female XLR connectors and 4x male XLR connectors, while the ‘RX’ have 2 sets of 4 male XLR.  In the case of the ‘TX’ boxes you can use them as sex changers and don’t necessarily run signals the way they’re intended.

Transformers: More than meets the eye

There are multiple different versions of the Catapult, with transformers optimised for mic (ending with an ‘M’) and line level (ending with an ‘L’) signals.  They way they’re arranged is to isolate the 2 sides of the catapult box, but could also be used to interface unbalanced signals from things like laptops.

Something I can think of a very good use for them is for running out comms feeds to set.  Typically we use small battery powered ‘beltpack’ TX for this, which only have an unbalanced input.  Here you could put in a long run along one CAT5 cable without worrying about interference on the audio getting to the comms transmitter.

Another approach is to use a ‘plug on’ transmitter designed for balanced microphone inputs.  However, it uses the cable shield as an antenna, and a 50m antenna is less than optimal for UHF. The transformer will break this up and a patch cord will have a better antenna length.

In this case, the TX4L would be the best box for this, plugging any microphones into the ‘input’ end and transmitters on the ‘splits’ of the other 2 channels on the other side of the transformers.  These could run to either a TX or RX box (although sex changers would have to be used with the RX to run the transmitters the ‘wrong way’ up the CAT5 cable)

CAT5 is for networking

Who said network audio had to be digital?  With multiple boxes it is possible to route signals to multiple locations using splits and the fact that dual CAT5 connections are on each box allows this.  The transformers can also help isolate different systems running form different power sources and they have ground lift switches to avoid ground loops (however this will mean you lose phantom power).  Do bear in mind the 3dB signal loss for each split, though- if you wanted to do something particularly complex it’d be worth getting amplifiers in to compensate.

Audio interfaces as location mixers

This is a bit of a ‘thought experiment’ as I haven’t actually got any of the kit to try out and found whether it actually works in a production environment or not.  I’m also not sure if this is currently a workable solution for me and will state the drawbacks, but this could all be useful to some people- at least as a bit of an experiment

Currently there aren’t really any digital mixers suitable for location work and I’ve been looking at potential solutions to this.   I’m aware that the Yamaha 01V96 is used quite a bit (in the US especially), but it’s big, power hungry and AC powered only.

A possible solution now is that a number of computer audio interfaces will work as standalone mixers (with a suitable control surface).  They have a considerable amount of DSP power available with the ability to run EQ and multiple submixes.  Another advantage is that audio can be sent to a computer, for playback of previously recorded tracks or even processing (auditioning noise reduction, for example).

Having done some research, here are some possible combinations of equipment:

Metric Halo ULN-8 / LIO-8

Metric Halo ULN-8

Effectively these are the same box, except the LIO-8 is a cut down version of the ULN-8, with no microphone preamplifiers or additional DSP plugin licenses.  They’ve been around for a while and use top quality components.  Metric Halo do continually support their products and are the only company I’m aware of who offer hardware upgrades to their audio interfaces.  At the moment there’s been mounting rumours of an upgrade to the DSP and interface with a 3D card (which would not involve buying a whole new unit), which would add a class compliant USB-C computer interface, improved DSP power and an additional card slot.

This is the only computer audio interface I’m aware of with a locking DC connector (4 pin XLR)!  There’s also a second barrel plug, which could be used for redundant power.  It has another unique property in that it’s the only DC powered interface with sample rate converters on the AES3 inputs.  This means I could run my radio mic receivers directly into it using their digital outs.  It’s got 8 analogue audio I/O and 8 digital AES3 I/O

Now for the drawbacks: it’s a big box- a deep 19″ rack unit 432 x 330 x 44 mm but it weights 2.6kg which isn’t too bad.  It currently only has a firewire interface and OSX drivers so requires a good bit of fiddling to get current computers to work with it.  They really need to update this and talk of the 3D card being ‘coming soon’ has been going on for about 2 years now.

Also, with the current architecture, the midi input will accept controllers using the mackie control protocol but needs to have a computer running in order to be able to control the mixer



These are effectively a load of different interfaces with different I/O which can be combined using the AVB protocol.  For a while there was just the Ultralite AVB which could be DC powered, but at the end of last year a couple more, the 624 and 8A were released. Furthermore a whole bunch of digital boxes were announced last month with AES3, ADAT and MADI interfaces.  All of these are in a compact ‘half rack’ format

I’m particularly interested in the 8D, however only half the inputs are AES3, the other 2 are SP/DIF and may require adaptors and/or sample rate conversion

The DC inputs aren’t locking, but will take 12-18V, only draw 10W on the current half rack interfaces and they don’t care about polarity either

The main drawback is controller integration- they won’t accept midi control, only OSC over a network.  Their suggested method is using a tablet computer using a web interface. It should be possible to hook up a tablet to a midi controller and use an application such as TouchOSC or Lemur to control the interface as a mixer.  Another future possibility is programming a BomeBox, although that doesn’t have OSC compatibility yet

RME UCX / Babyface Pro


RME Fireface UCX

These RME interfaces will all work with their totalmix FX mixer out of the box, and accept Mackie control midi commands.  A few features such as some of the talkback functionality won’t work without a computer, however.

The drawback, however is with some of the digital interfaces used.  They all us ADAT optical format, which isn’t common in broadcast equipment, so a converter box is required.  RME do one, the ADI-4DD, however it doesn’t have any sample rate converters, so 2 AJA ADA4 boxes would be required to provide use with mutiple digital sources which cannot be connected to word clock.  Again, power is with a barrel plug (and it’s not too fussy about voltage or polarity), although the babyface can also be powered over the USB bus, so could be a redundant power connection.

Waves / Digigrid LV1


Waves LV1

This is a system designed to work as a powerful digital mixer with a dedicated computer running all the mix software and also plugins at low latency.  It’s not cheap, but is built for purpose.  Working it on DC power may be a challenge (and I expect it may be greedy), however and would require a bit of hardware hacking- looking at the motherboards on some of the host computers (the smallest Impact model, for example will run from 12V but would involve fitting a 12V PSU and invalidating the warranty).  Interface wise, only the MADI ones will run from 12V, so a MADI converter with the I/O you require would be required.  DirectOut make the Exbox.AES which converts 16 channels of AES3 to and from MADI but without sample rate converters (but is has redundant locking DC inputs!)

Keith McMillan K-Mix

Keith McMillen K-Mix

This is actually a real hardware digital mixer- 8 analogue in and 10 out (including the headphone out, which can be freely assigned).  I’ve bought one of these and it’s a really compact and useful machine.  However, it doesn’t quite cut it for me I/O wise- I could do with some digital ins and outs.  It’s powered over USB, but can accept 2 USB connections, so redundant power can be supplied.  The touch control surface is surprisingly useable, there are ‘tracks’ along the faders and indents at 0dB.  The only disadvantage with the touch control is you can have ‘jumps’ if you take your finger off and it’s not in exactly the same place as where the fader is.  The K-Mix works with the Keith McMillan MIDI expander so can use 5 pin DIN cables

Icon Platform M

Icon Platform M

This is just a control surface- but a small DC powered one.  I owned its predecessor, the iControls Pro which wasn’t bad, although from picture it looks like they may have improved the build quality since.  The motorised faders are 100mm but did require a press downwards before moving them, so weren’t super smooth.  In fact I quite like the idea of having smoother, non-motorised faders on a control surface).  Icon have also recently showed off an expander, the Platform Z which adds blocks of 8 faders to the ‘M’.  This is designed to work with a computer so only sends class compliant MIDI over USB.  Various boxes are available which will work as MIDI hosts, however

Asparion D400

Asparion D400F and D400T

This is another control surface, again with motorised faders, a modular system except the build here looks more rugged than the Icon at first glance and has more buttons (but less knobs).  Also USB out only so may need a host device if not being used with a computer

Professional Field Recorder comparison

There’s been radio mic comparison table up on this site for years now, and I had the bright idea of doing one for recorders, partly as a lot of people don’t really know what’s out there (and some assume it’s just Sound Devices).  I’ve only included those with features suitable for professional use in the field – timecode, metadata input, DC power, reasonably sturdy build and those that are current products. I have missed off the Sound Devices 702T and 744T as they have relatively low track counts compared to most of the other machines.

Also, there isn’t any info on ergonomics or sound quality as they’re both subjective.  The only machine it’s not possible to mix on (but you can route) is the Sound Devices 970- which is really designed to have a mixer in front of it, in some ways that is a bit of a different beast and is the only one which can accept a MADI feed.  Please let me know if I’ve made any mistakes or omissions, this is mostly from published specs:

Edit:  Added Aaton Cantar Mini specs.  I’ve also missed off the Sound devices 664 as it’s similar in specification to the 688

2019 Update- added Sound Devices 666 (or ‘Scorpio’, as they insist on calling it) and Zaxcom Nova

  Mic/line inputs Line inputs AES3 inputs AES42 inputs (pairs) Max Inputs to tracks Rec Tracks available (192kHz) Rec Media
Aaton Cantar X3 8 4 8 2 24     24 (24) SSD, 2xSD, USB
Aaton Cantar Mini 4 2 4 2 10     16 (16) SSD, 2xSD, USB
AETA 4minx 4 6***** 2 2 8     8 (8 at 96kHz) SD
Nagra VI 4 2 4 0 8      8 (8) HDD, CF, USB
Roland R-88 8 0 2 0 10      10 (4) SD, USB
Sound Devices 633 3 3 2 1 6      10 (6) SD, CF
Sound Devices 688 6 6 4 2 12      16 (6) SD, CF
Sound Devices 788T 8 0 8 4 8      12 (4) SSD, CF, Firewire
Sound Devices 970 0 8 8 0 64      64 (32 at 96kHz) 2xSSD/CF, 2x eSATA
Sound Devices 666
(or Scorpio)
 16  4  32 36 (18)   SSD, 2xSD
Sonosax SX-R4+ 4 2       10* 4 16      16 (16) 2xSD
Tascam HS-P82 8 0 8 0 8      10 (4) 2xCF
Zaxcom Deva 24 12 4 24 8 24      24 (24 at 96kHz) SSD, 2xCF
Zaxcom Maxx 4 2      0/4***       0/1*** 8      8 (4) CF
Zaxcom Nomad 6 4       0/8***       0/1*** 10      10/12*** (10/12 at 96kHz) 2xCF, USB
Zaxcom Nova  4  2  4  10  12 2xCF 
Zoom F4 4/6**** 2 (unbalanced) 0 0 6      8 (8) 2xSD
Zoom F8 8 0 0 0 8      10 (8) 2xSD
  Balanced Outputs Unbalanced Outputs AES3 Outputs Output buses Multichannel Options Control surface Extras
Aaton Cantar X3 8 0 12 40      Dante 32×32 Cantarem 2
Monitor output, waveform display, play/rec, wifi, bluetooth
Aaton Cantar Mini 8 0 4 12       Cantarem 2 Monitor output, waveform display, play/rec, wifi, bluetooth
AETA 4minx 4 6***** 6 4   MIDI Soundfield monitoring
Nagra VI 2 0 2 4   MIDI  
Roland R-88 8 2 2        8 (direct)      USB interface 10×8 MIDI  
Sound Devices 633 4 2 4 6   CL-12 Wingman Remote
Sound Devices 688 8 2 8 8   CL-6, CL-12 Mix Assist, Dugan, Wingman remote, SL6
Sound Devices 788T 6 2 6 6   CL-8, CL-9 Mix Assist, CL-Wifi, GPIO
Sound Devices 970 8 0 8 64       Dante/MADI 64×64   RS422/GPIO/Network remote
Sound Devices 666
(or Scorpio) 
10  10  Dante 32×32  MIDI (MCU)  Android app 
Sonosax SX-R4+          0/2**                  2/6**     2/6**         4/8**      TBC network audio RC8+ wifi web interface
Tascam HS-P82 2                        0 8      10 (direct)   RC-F82  
Zaxcom Deva 24 10 0 12      10 (12 direct)   Mix-16, Oasis Nomad Touch, MixAhead
Zaxcom Maxx 4 2 0/4*** 4     Zaxcom digital tx option, Automix
Zaxcom Nomad 10 2 0/6*** 6   FC8, Oasis, Mix8 Zaxnet, Nomad Touch, Automix
Zaxcom Nova 8  0  6   Oasis  2x receiver slots for QRX212 
Zoom F4 2 2 0 4      USB interface 6×4 FRC-8  
Zoom F8 2 2 0 4      USB interface 8×4 FRC-8 Bluetooth remote app 
  Battery / power connection Dimensions (mm) Weight (kg) Notes      
Aaton Cantar X3 2x eSmart 2054, XLR4 90x320x240 3.55        
Aaton Cantar Mini 2x eSmart 2054, XLR4 90x259x234 2.3        
AETA 4minx Sony DV, HR10 75x260x195 1.9 ***** EXT I/O connector shared       
Nagra VI Nagra, XLR4 74x310x285 3.8 (weight with battery)      
Roland R-88 AA, XLR4 93x260x235 2.67        
Sound Devices 633 AA, DV, HR10 60x240x160 1.1        
Sound Devices 688 AA, HR10, NP1 (in SL6) 53x320x198 2.21        
Sound Devices 788T DV, HR10 45x257x153 1.7        
Sound Devices 970 2x XLR4 84x218x262 3.4        
Sound Devices 666
(or Scorpio) 
DV, 2x TA4 51x320x205 2.63      
Sonosax SX-R4+ eSmart 2054, HR10 50x200x144.5 0.91 *2 shared with aes out, **2nd figure with xlr5 output board      
Tascam HS-P82 NP1, AA, XLR4 100x270x260 3.65        
Zaxcom Deva 24 2x HR10 76.2x267x177.8 2.45       
Zaxcom Maxx AA, HR10 51x191x133 1.13 ***option variants      
Zaxcom Nomad AA, HR10 51x251x178 1.72 (weight with batteries)      
Zaxcom Nova 2x HR10 51x210x152 1.16 / 1.56***** ***** weight with 2x QRX212 modules     
Zoom F4 AA, HR10 54x178x141 1.03 ****line level only on jack, additional input option APH6XLR      
Zoom F8 AA, HR10 54x178x141 0.96      

Sonosax SX-R4+ v2 firmware

I’ve owned a Sonosax SX-R4+ for around 6 months now and I generally stand with what I said in my initial review:  the machine has been a pleasure to use, sounds fantastic and has a lot of recording power in a small box.  I’ve managed to get by with it on its own in a number of situations but with the v2 firmware it really opens up the machine and removes these limitations.

This is based on a v2.0 release candidate version of the firmware (which won’t be publicly released), there’s been a few bugs ironed out of this and v2.1 should be up on the website very soon.


This is the big one, so I’d better get this out of the way first.  In v1 of the firmware the 4 main knobs on the front are ‘hard set’ to gain control of whatever the 4 XLR inputs are.  Although it was possible to mute at zero and control gain ranges (so it was possible to mix on them), the ISO track levels would also change- so post would have to undo these gain changes.

Now this is no longer the case: the v2 firmware has  “fader modes”.  2 different fader curves are available -60dB to +12dB (with a steeper rolloff at the bottom) and -60dB to +24dB (linear).  Both mute at -60dB.

Faders are assignable to tracks on the mix configuration screen, and single faders can be assigned to multiple tracks for stereo or surround work or even as groups.  This also now allows me to run my radios (Wisycom MCR42) in AES3 as before the gain was fixedto being ganged across both AES3 channels on each XLR.  It’ll also allow me control levels using the AES3 inputs on the accessory port (when I’ve sorted out the cabling)


If a fader is not assigned to a channel which is assigned to mix, then it comes through as if the fader is at 0dB.  It’s possible to mute by changing the mix assignment (which is possible while recording)

Gain structure

So, how do you set gain and fader level with only one knob?  As default the push buttons on each knob are the input settings and PFL for each XLR input (long press can also be assigned), so whatever’s going into each of these channels can be soloed and gain adjusted with the menu knob (gain is the initial setting on the input screen).  Here’s a video:

Also, due to the high dynamic range of the converters it’s possible to set gain very conservatively and set up the mix tracks to be up to +20dB higher than the ISOs.  With another 24dB available at the fader it’s possible to work with 44dB of headroom with unnoticeable loss on the ISO tracks if desired.  With the AES3 inputs you’re limited to what happens on the analogue end of whatever you have plugged in, but can have them come in a 0dB and again boost in the mix.  An issue however with setting ISOs this conservatively is it become difficult to PFL as there’s such a big difference.  Personally I might only use these more extreme settings for scenarios where there may be more extreme dynamic range.

Routing Setings

Routing works so that inputs (and mix tracks) are assignable to any 1 of 16 tracks.  These can then be assigned to 2 mix tracks, or any of the outputs on the machine.  Again, anything can be assigned to anything.  There’s also due to be a new output board released soon with an XLR5 connector, switchable between 2 channels of balanced analogue, 4ch of AES3 or unbalanced analogue out. This gives a total of up to 8 outputs over a combination of unbalanced and AES3.  Something I have noticed is that it’s not possible to send individual channels post-fade to outputs, though- which could be useful for mix-minus.

Although it’s now possible to separately assign the inputs, faders and outputs, it’s reasonably easy to keep a handle on what goes where.  The new colour coding to channels also helps.  The record tracks matrix shows input, track name, arm and colour.  Mix menu and output menus also show track assignments and have recallable presets


User Interface

I found I could navigate this recorder very quickly using the v1 firmware, however more programmable buttons and features have come online in the v2 firmware.  All buttons (7) and 5 touchscreen areas can be programmed to perform different functions with both short and long presses.  Shortcuts for channel muting is also something which isn’t there and I can see that being useful  The Mix setup screen has also been brought up a level in the menu to the main screen.

Sound Reports

The R4+ now generates sound reports straight to the SD card.  Currently all the metadata is there, but the headers aren’t customisable. It’s generated automatically as an HTML file so readable in any web browser (javascript does need to be turned on to read it).  I also looked for a ‘generate sound report’ button and couldn’t find one.  However I just found the report to be generated on the SD card and is updated on the machine continuously.

Here’s an example report:


At first glance this machine looks like it’s something similar in size and capability of the Sound Devices 633 or Zaxcom Maxx, however there’s quite a lot more crammed into the box.  The interface feels more like a larger recorder such as the Zaxcom Deva and as long as you have access to digital outputs or with an ADC it has the power to be used behind a bigger mixer and be able to deal with complex drama jobs.  I don’t believe there’s anything else that can cram so much mixing and recording power into such a small space.

A feature it doesn’t have compared to the Sound Devices 688 and Zaxcom Nomad however is some kind of automixer, and although the control surface was announced a while ago now, both Sound Devices and Zaxcom have their own control surfaces released.  When I had my hands on the pre-release physical mockup I found it had super smooth faders but was a bit cramped.

The R4+ does, however have a considerable amount of DSP power inside, though- so can potentially see additional features being added

Wisycom MCR42 v3.x firmware

I’m doing this post as I’ve realised quite a few people with wisycom haven’t updated their firmware and there’s a quite a few nice features they’ve added since v3 on the MCR42.  The new UPK mini programmer is also available, which is considerably cheaper than the older UPK300, which allows much faster changing of frequencies, locking, unlocking and hiding of frequencies and allows you to update firmware.  NB: if using windows 8, the installation process is a bit convoluted- there’s a help file in the wisycom manager 0.8 program.  And you need to press the connect button for it to see the UPK.

First up, if you’re used to using the MCR42, it initially appears that you’ve got an extra menu layer to navigate, the ‘Edit RX1’ and ‘Edit RX2’ are no longer at the base of the menu tree.  However, you can see and access the settings  through the new ‘quick access’ screens.  The only thing I’ve found I regularly use which isn’t in the quick access menus is the power on/off for individual transmitters.

These are accessed by pressing the ‘sync’ and ‘scan’ buttons which allow you to scroll through these new screens.  Hit ‘sync’ and you get to the RX1 frequency screen:

Pressing select allows you to alter any of the frequency settings, scrolling between channel, and group.  There’s an option to display by the channel name (in fast channel select in the advanced menu), but the frequencies aren’t displayed   There’s another similar screen for RX2.  Next is the RF screen:

This shows your RF strength from each receiver, with a bar for each antenna.  Hitting Menu/Select brings up an RF settings menu, where you can alter squelch settings.  Squelch is the threshold at which the receiver will cut out any incoming RF, this is to ensure when a transmitter goes out of range, you don’t get a burst of static coming through.  There’s a new ‘Auto Squelch’ feature, which runs a scan and sets squelch threshold based on the RF in your environment at the frequencies your receiver is set to.

To run a more general RF scan, hold the ‘scan’ button when in the main screen and choose a receiver and group to scan.  Use the ‘Center’ group (00 as default) of frequencies to run a broadband scan and the regular block of freqs you’d use for more detail over a smaller area. There’s also an ‘intergap’ group, which I think is the frequencies at the start and end of groups. It pulls up a graph in order of ‘best’ to ‘worst’ freqs, if you want to see it in frequency order, press sync and scan at the same time.  If you’re using a user frequency block, I’d advise hiding all the slots you’re not using, so it doesn’t scan your lowest frequency on the RX loads of times.

Finally there’s the Audio screen- this is easiest to access by pressing ‘scan’ once from the main screen (you can also scroll through the other quick menus first with ‘sync’):

This shows your expander settings, audio output level (I generally keep them on +12dBu, this is the level that the DAC outputs the signal, anything else is attenuated) and has big modulometers for each receiver.  Although the increments aren’t marked, I’d guess they’re all 6dB (as the bottom is -42dB and top is 0dB and there’s 7 markers).  It’s so much easier checking levels now.

Finally, the preset feature- it’s in the main menu, second item down (under infrared).  There’s 3 presets (you can rename them using the infrared programmer and software), if you hit ‘save’ and select a preset- it’ll save the current settings and return them when you restore that preset again.  This receiver has presets for camera hop frequencies and talent mics 7 and 8, for example and I can now change between the two easily.  It’s also possible to put different expander settings on different presets.  Expander settings can be tied to channel numbers in the MCR4x manager program:

Here I’ve set channels 22-34 to have the sennheiser evolution expander, and programmed group 12 to have the Channel 38 preset frequencies for this system.  There are loads of channels per group, so you can do this.  This does, however work across groups- so try and keep certain channels for certain transmitters only.  You can hide the frequencies before the first one you’re using (and you can select multiple blocks using shift/ctrl+click for locking and hiding, whcih saves time).  Presets can also be used in the wisycom transmitters, specifying input levels, frequencies and compander settings.  There are also updated ENC and ENR 1.2 companders, introduced in v3.3 firmware.  These have a 1.2:1 compressor on the output for use with DSLRs and other noisier consumer inputs- no difference to the TX.

25 pin modular system

This is a bit of an ongoing project, but started having thoughts about it after working with an Audio Ltd 2040 system while assisting a production sound mixer on a drama job.  We were having serious range issues throughout the job, the cause of which was possibly something attached to the camera.  The only way we could get round this was to move the receivers closer in ‘remote boxes’.

These were an RK3 rack in a box with a battery and antenna inputs and outputs, and we rolled out either individual XLR cables or a multicore to connect to the main trolley.  As the receivers themselves are very expensive, it’s not really practical having duplicates doing the same thing, so it was a case they could quickly be pulled out of the RK6 and slotted straight into the remote boxes.

However it’s a case that it’s not possible to do this with other receivers, such as the Wisycom MCR42, which I use.  There is, however quite a common standard for camera receivers.  Pretty much all slot in receivers have an option for a universal ‘Panasonic’ standard 25 pin connector on the base, which will output 2 channels of balanced audio.

So, I’ve now got 25 pin bases for all my receivers.  There are a number of options for antenna, audio and power distribution, which have 25 pin options.  I already owned the Audio Ltd EN2  distribution rack (which still isn’t up on their website, it’s about £550 +VAT) but got an additional 25pin base.  I was scatching my head and looking at getting something made up so the receivers slotted in, but realised the camera mount brackets had holes in the same place as the mounting points on the audio CX2 receivers.  Audio do a base for the receivers with a bar with mounting points on. So just screwed on the brackets and  now have slots.  A disadvantage with the 25 pin section on the audio ltd distributor is that it adds a bit too much weight, there’s a steel plate along the back and I’m not sure it really needs to be there.  When I get some time, I may drill out sections from that

The second mounting solution I have is a Lectrosonics Octopack.  Here it’s a case that the screw holes are in different places to those on the wisycom receivers, however Richard Meredith’s Audio Dept made a run of very purple mounting flanges, so the receivers sit in the slots properly and can also be screwed in so won’t come loose:

It’s not just wisycom which will work, almost any ‘slot in’ camera receiver should have a 25pin option (except Sony, who don’t like to play with others).  Other examples are Lectrosonics SRb, Audio Ltd CX2.  There’s also another distribution system, the PSC Six Pack.  There’s another mod to the wisycom camera plates (see the picture further up on the Audio Ltd distributor) where grooves have been drilled in the camera bracket so the cables can fit.

You can also ‘mix and match’ different brands of receiver, however they don’t always orient the connector the same way round. Here’s a Sennheiser EK3041 (it’s actually on, but the display’s nowhere near as bright as the wisycom):

They also work on their own without antennas, here’s a quick and light cable for the back with power and audio connections:

What gear should I get?

Loads of people (mainly if they’re new), ask this question, and the answers are unfortunately more questions:

What do you want to do?
How often are you going to use it?
How will it work with other gear?

It’s quite easy to get sucked into the idea of buying things (ooh, nice shiny lovely things) but a lot of the time, unless you’re using whatever it is on a frequent basis, you’re probably going to lose money on it.

Have a look at a local rental company (for example, in London there’s Richmond Film Services, The Audio Dept and Better Sound to name a few) and see how much it costs to hire whatever you need.  Also it often costs only slightly more to hire professional level gear (Audio Ltd, Sound Devices etc), over consumer gear (zoom, sennheiser evolution) while the professional level gear will be more robust, sound better and be able to interface with other professional gear more easily.

Also look at the features in gear that work for you personally and get the gear that works best for the way you find you work more often.  There’s a few things that can catch you out around returns/routing on certain mixers which you sometimes expect to be there and sometimes aren’t (like where the return signal can be routed, is there a ‘bus in’?)

Also, always factor in the cost of cables when you buy something, you often need quite a few new ones with obscure connectors on


Bag of f-stops

Just bought a new backpack for carrying most of my day-to-day gear around for doco type jobs after the old one was starting to get a bit small and won’t be able to fit my sound bag with the radio distribution system I’m putting together.

After having a look at lots of different bags, I found those designed for photographers seemed to fit my needs best, as they have quick access and you can see what’s inside them, so it’s harder to lose things in them.  Another criteria I had was to be as large as possible, yet still be able to take it as carry-on luggage on flights.

I ended up going with an F-Stop Loka in a nice loud blue colour so I can find it easily with a large “ICU” (removable bit with all the protective padding).  It’s really light and I think I’ve found all the pockets now.  I found the lowepro equivalents to be quite a bit heavier and found the protective compartment in the Vertex wasn’t deep enough to get my sound bag in.

Here’s the back that opens, so  can just lift my bag straight out, transmitters are in the side bit behind the big divider









Cables, adapters and memory cards are in the flap that opens:

Mics go in the top, with hypers/cardiods in the small peli underneath (you can see it on the back)

There’s also space for a laptop or ipad down the back of the ICU and a couple of spare XLR cables.

Boom pole and light stand (together they make a lightweight mic stand) go on the sides. Harness can also attach to the front

Batteries in the front pocket (might be able to squeeze a charger in too)

And last of all, in the top pocket, I’ve got a pocket recorder for quickly grabbing atmos or as an emergency backup.  Along with in-ear headphones and some tape and velcro

It’s looking like this will replace 2 bags at the moment and hopefully result in less strain on my back.  I also think it holds more than my wheely petrol bag

Rocknroller mini trolley

It’s nice to be able to sit down in order to concentrate on mixing.  And on drama sets you’re often in a different room so need to be able to see what’s going on through a monitor in order to be able to queue fades and be able to put a script up and follow it.

As a bit of an experiment I’ve put together a ‘mini trolley’ .  You can spend *thousands* on putting together a decent one, but I’ve mainly thought of getting something I can pop my bag on and look at a monitor (or even two).  It’s a Rocknroller RMH with 2 laptop shelf attachments.  It’s designed as a sack truck really.

This is sort of a proof of concept, I’m wondering about maybe cutting back the top shelf so it doesn’t go as far forward (they’re made of wood).  In this setup it won’t actually stand up with the bottom lip extended (as a sack truck) and leans forward.  With the lip in it actually leans back a little but would fall over if something fell into it.  I’ll also be coming back to those antennas when the cables to test them have arrived…

However, this seems to fix the problem:

Now, if I could get some drawers in that petrol bag…