Tuesday, 23 October 2012

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


Sunday, 21 October 2012

Buying, Selling and Prevaricating

As I do a little bit of lecturing for Lincoln University, one of the most common questions I get at the end of lectures, or by email, is with regards to buying equipment. Inevitably when starting out, money is very tight, but I always quote the axiom of "Buy Well - Buy Once". And more often than not advising people against buying a mediocre recorder (which is more often than not what I'm asked about), but to buy a good second hand mic (either a sennhiser mkh 416 or mkh 60 with full rycote) and to buy a good second hand small mixer (more often than not a sound devices 302).

All about the Pre-Amps

Tristan Ofield and I did some very non scientific tests a couple of years ago, to try and find the weak spot in his recording chain. He had a beyerdynamic shotgun mic and one of the Zoom H4n recorders, and he was having a problem with the amount of hiss on his recordings. I've had a Zoom H2 pocket recorder that I carry round with me as an ultimate backup / emergency recorder, but I'd been actually quite impressed with the noise floor - but the key thing was that I was using a 302 as the pre amp. We played about swapping microphones over (and both the sennheiser mics (416 and 60) did have a lower self noise compared to the beyerdynamic), but it really became so clear just how important those microphone pre-amps are, as it gets the signal into the recorder at line level - giving a reduction in the noise floor, and the huge benefit of the incredibly smooth limiters that can prevent digital distortion.

Buy Well - Buy Once

And I'm starting to realise that I really should start to listen to my own advice. I've had a very busy year, and it has meant that I've had to invest a (more than) fair portion of my earnings into kit, and I'm starting to realise that I'm now in the position of replacing kit that I bought when I started out - as the original kit simply not good enough. The first location mic I bought was an ME66 (and I also had a ME64 module) and when I sold it a couple of years ago I really was pleased to get rid of it - as I had just come to hate the sound of it. And I'm not even going to mention the Sony WRT805 radio mics that I bought, that were truly, truly useless. I'm currently in the process of buying an MS stereo MKH 50 / 30, as I've never really taken to the sound of the pearl stereo mic (the MSH10) that I own (see blog entry) - and the huge advantage with this new set up is that it gives me an MKH 50 to use on interior dialogue, and I can change the nature of the stereo image by using a MKH 60 as the M element, which can be incredibly useful when working on documentary (nice tight M mic with the 30 as the S mic to provide a nice stereo fill).

Retail Therapy

I'm currently looking at buying a very simple / portable audio interface that I can use with my new shiny MacBook Pro for the simpler playback requirements that we get asked to do on location. And this time I'm determined to Buy Well and Once. I've been looking at getting a cheaper and simple interface (something like the Focusrite Saffire 2i2, but why don't I put this money into buying a high quality one (Apogee Duet 2) that I can actually use as an additional to my Digi 003+ rack in the studio - especially now that Pro Tools 10 allow aggregate interfaces, and works with different manufacturers. And the quality of those pre amps and converters will be brilliant....but do I really need this for a playback rig.... But then....neither of these have a MIDI interface....and then I've just seen that Apogee Quartet....and that has a USB MIDI input.....sorry where was I? I think I need some advice about buying kit - do you know anyone?

21st October 2012

Thursday, 4 October 2012

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
Micron A
606.125 A


Senn Tx 2

606.675 N



Micron B
607.375 Y



Micron C
607.925 B


Micron 2
Micron D
608.300 C




608.900 D


Micron 1

609.325 P




611.825 E


Ch 70: Un licensed

612.300 F


Private Comms

613.000 H


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