CPD - The IPS Training Weekend 2012

One of the many tricky things about being freelance, is the issue of training and continued professional development (CPD). So it's great that the Institute of Professional Sound run a yearly training course that brings together a range of sound practitioners, from a range of broadcast disciplines, and puts together a two day programme with experts and manufacturers that helps sound professionals develop and continue their training. This years course has just been held at the NFTS in Beaconsfield - suitably entitled Radio Ga Ga - and has covered the trials and tribulations of Radio Microphones.

Radio Ga Ga

The first sessions covered the terminology and theory of analogue and digital / digital hybrid radio microphones. Much of the terminology translates across the analogue / digital divide, but what was interesting was to see how the digital radio mic's fit into our analogue RF spectrum, and the potential interaction between the two systems. The recent Digital Switch Over (or "analogue switch off") in the UK has meant that we have far less spectrum available to us, whether we are working in the electronic handbag, on a drama trolley or a  reality / LE show that requires huge numbers of radio / IEM channels; so what has become essential is that we learn how to make the most efficient use of the available spectrum and our own / hired in radio equipment.

Meet the kit

The Lintec T Dipole

There was a wide range of manufactures and suppliers of radio mic kit present at NFTS, and it was great to be able to go and look, handle and listen to the kit that is currently available and see what is suitable for each application. There was radio mic equipment from Micron, Audio Wireless, Audio Limited, Sennheiser, Sony, Zaxcom, Shure, Lectrosonics and Wisycom. Lintec Antennas and Rycote were also there, as their products are key to the implementation of radio mic's.

Microns's Mini TX with Audio Control.

It was great to have such a range of kit to compare and contrast, and it was great to see in the flesh and ask the manufacturers / suppliers questions..highlights for me were the small transmitter from micron, the amazing flexibility of the Wisycom system, the build quality of the lectrosonics kit, the integration of the entire zaxcom kit (along with ability of the radios to record the audio pre transmission with timecode on a micro SD card), the un-companded sound of the Sennheiser digital mic and the T Dipole from Lintec - that's a specially designed antenna rig that clips onto the harness when working in the electric handbag.


Everything in it's place

Other specific sessions over the weekend covered microphone placement techniques (including a really good comparative listen to just how radio microphones sound when placed on a contributor, and that was one of the most enlightening experiences (huge thanks to Heidi there)), a dedicated look into frequency planning for events large and small (which showed how the DSO has really squeezed the radio mic allocation in BBC TV centre (and who to contact when using RM's there, and at other places)), specific details on the new digital radio mic's from various manufacturers, some insights into the black arts of RF and what to look out and listen for on location (and the JFMG is our friend), and then finally great Q and A with all the presenters which included a tech analysis of the radio mic's that had been brought along by the manufactures looking at their inter mod components, RM channel bandwidth for specific TX's and their masks (and if you don't know what those terms mean, then this course was for you)

And Finally

There's many snippets and gems of wisdom that I've come away with after this weekend's training, but I think for me there were three over-riding themes that should be shouted far and wide:

Firstly, both digital and analogue radio systems has pro's and cons,  but what became clear through out  the course of the weekend was that the best analogue radio mic's have now reached their performance limits, and that although there will 'always' be a place for analogue mic's, the future is looking very much towards digital systems.

Secondly, the value of meeting and talking to fellow practitioners. It's so rare we get to talk to other sound professionals these days, and it's invaluable to catch up and share knowledge. The coffee breaks and meal times offered shared wisdom and experience, just as much as the main sessions did.

And thirdly, if you are using radio microphone in the UK - really check whether you need a license; and if you do, bloody well get one.  The recent DSO has cost the PSME a huge reduction in available RF bandwidth, and this reduction will only continue in the future - and unlicensed users are making a painful rod for their own, and everyone else's, back.  With the recent consultation on WSD's , once again our radio spectrum is under threat, and if it does go ahead, the only way a device will know whether you are there is if you have a license registered on the database.  The JFMG offer a great service and support to RM users in the UK, and the cost of a license is negligible - and if you've not got one, it may just cost you your shoot.

A great course and weekend - when's the next one?

G
11 Feb 2013.

FreqFinder - The Must Have App for Location Recordists?

Google App Store

As we all know the "App" market place - be it on Apple, Android or any other operating system - has changed our lives and the way we use (and abuse) our smart phones / tablets. There are a vast number of music related apps - especially for the Apple market, but there are not that many that are designed for the location sound recordist; which, to be fair, is not that surprising as we are a fairly niche group to say the least.

So last night I was completely taken by surprise when the forum members of the Institute of Professional Sound highlighted a absolute "Must Have" App for location sound recordists and anyone who uses radio mics on location.

Freq Finder

FreqFinder (written by New Endian) is a nicely simple app that allows the user to enter the frequencies of radio channels and check for intermodulation interference across the channels. It comes pre programmed with the pre-set frequencies of the major radio mic manufacturers (both for the US and the UK - so lectrosonics, comtek, sennheiser, Audio and Micron) and allows the user to build up their own specific list of radios and check for intermodulation across the channels.

Ch38 Micron Explorer 100

In the UK an application like this is such a power tool, as Ch38 no longer has the pre defined channel list that the JFMG had set up in CH69, so it's much more of a free for all - as each manufacturer is trying to design their kit to make the best of the limited band width (for more rantings on that particular topic have a look at one of my previous blog pages).

Frequency Tables

Using FreqFinder with my fairly modest set up of Micron and Sennheiser radio microphone channels, was really straight forward. Freqfinder has preprogrammed into it (some of) the manufactures preset frequencies, so for the Micron explorer range it has the 16 channels that are standard for the Micron Explorer 100 series.

As I have the LCD range of microns, I'm not tied into this preset frequency set, so I have my radios pre programmed to number of inter mod free frequencies - but I can programme in an equivalent table  into FreqFinder to match how I'm working - and it should make it much easier check frequencies when working with equipment from different manufacturers and other recordists.

JFMG Shared

Practical use of the app.

This is very much a "first look" at this app and I've not had time yet to use it in in the field with my radios or in difficult RF environments. But something has made me query the accuracy of the app.  The JMFG have suggested a number of frequencies for shared use in CH38 that should be intermodulation free. Putting these frequencies into FreqFinder showed that there were intermodulation 'hits' on most of the frequencies - but practically I'm not sure yet what this means. When I get chance (probably later this week) I'll try and actually use the app in conjunction with my radio mics and see exactly what the practical implications of the information that it presents.

For those of us in the UK, be aware though that the TV channel number refer to the USA frequencies...so it can be a little confusing! The App costs £18.99, and may seem expensive, but I think the capabilities of a tool like this make it a price certainly worth paying.

23rd October 2012

G

Experiences with CH38

In the UK this year, we've been in the process of switching over our radio frequencies used for PMSE (Programme Making and Special Events) from channel 61 - 69 (790 - 862 MHz) to channel 38-40 (606.500 - 613.500 MHz). With access to channels 61-69 completely stopping in the end of 2012.

There's been plenty of posts and discussions about the politics of this switch over, but I've not read very much about the real world examples of switching over, and the experiences. So I thought I'd summarise what I've been through in the past year, whilst working on two big television dramas (Accused and Mr Selfridge) that required multiple radio microphones sets ups.

Allocated Frequencies

In the UK the radio frequencies for radio microphones are well co-ordinated by the JFMG. For Channel 69 (the old channel that was regularly used for location recordists) there was a set of 14 frequencies that were available to use and share within the channel, and various sub-sets of which were intermodulation free. This meant that it was fairly straight forward to get 7 or 8 radio channels up and running together, where ever you were and whatever brand of radio mics you owned; as each manufacturer made sure that at least some (if not all) of these listed frequencies were available.

In the migration to Ch38 (the new channel for the shared frequencies) the decision has been made by the JFMG to not specify the frequencies available within this channel - the reasoning being that its now possible for different manufactures to design their products to fit in more intermodulation free frequencies. Even though the JFMG has a list of suggested frequencies for Ch38, this means that each  manufacturer has a different frequency list...and suddenly it has become a lot harder to work with different equipment.

Complete Flexibility

Realising this, it made sense to purchase a radio mic system that was completely tuneable to any frequency, such that it would be possible to adapt to any combination of radio microphones and to set up the radios so that they worked in whatever situation. Most manufacturers now offer some radios that are completely tune-able, but each still have their own list of recommended intermodulation free frequencies. I'd been a user of micron radio microphones for a number of years, I decided to carry on using them, especially as they were now offering a tuneable LCD controlled set. I've a set of four of these now, that are set up in a pair of DDH3 racks with a pair of dipole aerials.  (I'm not going to review / comment on the radios themselves here...but may do later as I've found pro's and cons to them).

On the drama Mr Selfridge this year, it's been necessary to have a large number of radio microphones - up to eight on certain scenes, so this meant hiring in additional microphones to my complement of 4 in Ch38 and 2 in Ch69. So I naturally hired in microns...only to find that the hire company had changed the set of intermodulation free frequencies from the standard micron set. If I had not opted for a flexible system, this would have been a huge stumbling block as the two sets of frequency tables did not have any common frequencies (see the table below - micron specific is the standard set, micron modified is the set that came with the hired microphones). For info, the numbers in italics are the memory locations that I've set up within the micron LCD Rx and Tx, so that I can now swap between the standard frequency set, the 'modified set' from the hire company and the JFMG shared frequencies.

Ch 68: Licensed		Ch 38: Licensed			Ch 38: Licensed		Ch 38: Licensed
		Micron Modified			Micron Specific		JFMG Shared
Ch 69: Licensed		606.125	10	Micron A	606.125 A		606.600	0
854.900	Senn Tx 2	606.500	11		606.675 N		607.500	1
855.275		607.250	12	Micron B	607.375 Y		608.150	2
855.900		608.750	13	Micron C	607.925 B		609.150	3
858.650	Micron 2	609.625	14	Micron D	608.300 C		609.950	4
860.400		610.550	15		608.900 D		610.550	5
860.900	Micron 1	611.250	16		609.325 P		611.250	6
861.750		612.300	17		611.825 E		612.300	7
Ch 70: Un licensed		613.150	18		612.300 F		613.150	8
863.725	Private Comms	613.500	19		613.000 H		613.500	9
					613.525 T
					613.850 M

Ch 38 Itself

I've been using channel 38 since November 2011, and I've had mostly successful experiences but there does feel to be a definite difference to channel 69 - although I can't objectively quantify these feelings! My gut feeling is that the range is not quite as good, but this may be because of the ever increasing RF signals that as flying round set, from the wevi, the walkies, mobile phones, remote focus controllers and even the remote control for the smoke machine.

I'm also finding Ch38 to be more unpredictable that ch69 was. Previously, once a set of frequencies were up and working with a set of 4 or more radio microphones, this would remain to be the case - not withstanding location anomalies. But with Ch38, I can frequently find that one of my regular 4 radio channels will start under performing, with reduced range, increased background noise / compansion artefacts - a change of frequency usually sorts this out - but often this can be as quick as from one shot to another. It can be quite frustrating.

4 October 2012