Category: Reference

Traditionally, when setting up input gain the engineer sets it so that a ‘healthy’ voltage is coming into the system. A certain level of headroom is maintained in order to allow for unexpected peaks.  24bit analogue to digital converters have allowed us more flexibility in leaving headroom before system noise could become a problem.

Here’s a more traditional input diagram from the previous generation SX-R4 recorder:

I’ve been using the latest generation of Sonosax preamplifiers for a while now. I’ve known that they can handle a huge dynamic range since using them but I’ve only just found this in the AD8+ manual:

The thing which is initially quite alarming is that the only gain before the analogue to digital converters (ADC) is a switchable +20dB.  Most professional equipment will have low cut filters, gain and analogue limiters before the ADC stage. If something overloads the ADC, it becomes digital garbage.

In this case, the paired ADCs can take a considerable amount of level- +21dBu (which is 24.6V) and +1dBu (2.46V) with the +20dB option enabled.  To put this into context, most amplifiers are designed to take +18dBu max at input.   So the only “real” gain setting is the +20dB option.  In the unlikely event that an even higher voltage is coming in, there are analogue pots on the line inputs of the SX-R4+ (the small 5 and 6 knobs on the front).

This means more information is coming into the ‘digital world’ earlier in the chain and there’s no limiter- everything is captured as it comes in. The gain on any of the knobs, rather than controlling an amplifier is effectively a multiply function.  Sometimes you’ll need to add gain just to hear a signal, however it now doesn’t really matter where it is added as long as the signal isn’t turned back into an analogue one,  it will have the same result in post production as it will from the machine directly.  Even if it’s sent over AES3, it’s the same 1s and 0s. Whether your post production facility want to work this way is another matter.

So, it should be possible to use an AD8+ as an analogue front end and get the same results without putting any gain on the inputs and adding ‘digital gain’ in another mixer or computer

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

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.

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

Something which seems to have been gradually appearing is how all the data about what we’re shooting is now able to be logged and centralised much more easily. You can now run a computer network on set where script supervisor, camera and sound’s notes can be compiled together and matched to all the individual files.

Two different systems have started to emerge (very recently), Ambient’s Clockit Network (ACN) and Timecode Buddy (TCB) and related products. There’s also the Cameron-Pace metastrobe system, but I haven’t seen any documentation on it (and imagine it’s very expensive to hire).
ACN has been in development for some time and started appearing on Ambient’s newest series of lockit boxes (ACL204). They’ve had this video up since it began:
http://player.vimeo.com/video/42540614

Ambient have also teamed up with a company called Easyscott to deal with their logging and metadata distribution. It seems to be a powerful system, although it requires having a server on set which someone’s got to look after (they suggest the 2nd AC). Logging currently works on iOS devices but they’re planning compatibility with other tablets in future. The server’s also able to deal process a video feed, so playback can be done over the network, rather than the camera, which may save some time on set.

Something else Ambient have been talking about with ACN is actually being able to read/write metadata directly off machines via RS232/RS422. They had a demo of this working with a 3D camera rig at last year’s IBC (http://youtu.be/YNNUnBpo_NI?t=4m17s), where metadata was updated on a tablet but I’m yet to see it implemented in any audio recorders. I’d expect the manufacturers who have implemented ambient TC units in their products to be those working with this, however not all have an RS232/RS422 port on them (Sound Devices 7 series do, though). Ambient have also just announced new slate/TC display which works on ACN.

Timecode Buddy are the new kids on the block as far as timecode systems are concerned, their system works in a similar way to ACN (where timecode data is transmitted over wifi), but they also have a UHF range transmitter for transmitting TC between units.

They’ve teamed up with MovieSlate, who make a slate and logging app, which has developed into quite a powerful logging tool which will talk to TCB and receive timecode. I use it for sound reports, but with all the multicam plugins etc multiple iOS devices can share info across the network and receive matched timecode. Buying the app does add up though- it’s £17.50 for the app (on each device), but then another £35 each for the timecode, multicam and sound dept add-ons (making £122.50 per device). I don’t think there are any plans on moving movieslate to any other platforms and TCB have said they can only get the devices to display accurate timecode on devices where they know the hardware delays etc, so if making something for android they’d have to know every model of phone/tablet that would be compatible.

Denecke have also got onboard and are developing a slate which will receive TCB network information: http://www.youtube.com/watch?v=tl8jf_8gIOg

Finally, Movieslate are also working on adding a video feed from a Teredek Cube to the logging screen- so a live picture (or pictures) can be seen from the iOS device.  TCB are also working with Adobe in order to add timecode to their prelude live logger.
http://vimeopro.com/ipstv/ipstv-at-ibc-2013/video/74495522

Both systems look very capable, ACN/EasyScott looks like it’ll be able to do a bit more in future- but involves a more complex setup, while TCB/MovieSlate seems to be a bit more portable, as you don’t need to move a server around with you (and find power for it).

Time will tell whether one will be VHS and the other Betamax…
Zaxcom’s zaxnet system already sends audio and timecode around set, maybe metadata will be added to this?