Addition to post on synch'ing audio with video in FCP

***Addition (Feb 29th 2008) - the last paragraph discussing lining up the separately recorded audio with the picture from the camera, via timecode is not the best method. A much neater method is to use the MAKE MULTICLIP option within FCP and when asked how to align to audio with the video, simply choose MATCH BY TIMECODE. Once this is carried out, FCP will create a multi-clip with the separate audio perfectly aligned to the picture, regardless of whether it was started before or after the camera (the audio attached to the video file from the camera can then easily be removed from the multiclip). This method is also really neat when aligning footage from a multi-camera shoot to audio recorded on a separate device. If a clapperboard was used to align the cameras and audio recorder, IN points could be marked on each of the video files (i.e. at the frame where the clapper closes) and then the matching IN point could be marked on the audio file. By SHIFT+clicking on the same audio file with each of the camera angles one at a time and then creating a MULTI-CLIP and selecting ALIGN BY IN POINT, each of the camera angles will now have identical audio attached to them.

Alternative ADR software - "VoiceQ"

An alternative piece of ADR plugin software for ProTools is VoiceQ and a demo has recently been looked at, briefly. The software appears to be good, although integration with ProTools has not been tried as yet; only as standalone. What is nice about the software is that the actor's lines can be made to scroll across the video and also different colours and placements can be used for each actor.

"ADR Studio"

Recently I have been testing and teaching "ADR Studio" by Gallery. ADR Studio (as used by the likes of Skywalker Sound for the recent Star Wars movies), is a piece of software which manages and virtually automates the spotting of both Foley and ADR sounds within ProTools (and others). The software communicates with ProTools via a virtual MIDI interface, controlling its features via HUI (Human User Interface developed by Emagic / Mackie) and MTC (MIDI TIME CODE). It's a bit fiddly to setup, but once configured it works extremely well.

As well as automatically generating the standard 3 blips spaced 667ms (or 16 film frames) before the cue point, it also has a powerful matrix which lets the user decide what happens to each track during the PREVIEW, RECORD and REVIEW stages. For example, during the PREVIEW stage, the actor might wish to hear the reference audio both before, during and after the cue point. However, during the actual RECORD and REVIEW stages, they might wish to only hear the reference audio during the pre and post roll sections and then hear only their "live" input during the actual record stage; this is easily configured within the ADR Studio matrix.

Spotting of sounds / dialogue is also extremely easy as the line/s are simply highlighted and then upon hitting the SPOT dialogue box, a window appears where things such as the actor / character's name and line to be replaced can easily be entered. Then, an ADR cue sheet can be generated and printed out ready to give to the actor / Foley artist etc. A simple double click on the required cue automatically sets ProTools up at the required position within the timeline ready for previewing / recording or reviewing the cue.

An excellent piece of software - I plan to get hold of a copy for my own studio as this is an area I'd definitely like to move into / explore.

Panels complete

The existing panels have now had their infill replaced with a more dense 50mm Rockwool and also the two other ceiling ones have now been completed. The acoustic is much more dead now and stereo imaging has greatly been improved when monitoring via the Blue Sky monitors - it is quite amazing how much difference there is.

With some fabric left over and a couple of slabs of Rockwool, I might look into making a pad to go on the back of one of the doors between the studio space and utility room next door. Even with a double stud / double leaf fire door arrangement, noise from the tumble dryer is still audible. It's not a problem, but I might as well use up the left over materials!

One other thing to improve upon is the glass in the vocal booth. I plan to take out the sealed unit and replace it with two separate panes of 4mm and 6mm respectively.

Acoustic Panels - update

Not quite as much progress as I would have liked, but 3 out of the 5 panels were completed this weekend. The panel standing upright is for the ceiling; the two final panels for the ceiling will be completed this week. As can be seen from the third photograph, Glass Wool was used instead of Rockwool simply because the supplier sent me the wrong material! I think I may change the infill to Rockwool as its performance should be better than standard Glass Wool batts. More pictures to follow...

Back on with the Text Book

Have now decided to try and crack on with the Text Book. Focal Press were approached in May of this year and they seemed keen so I have now drawn up a proper proposal and emailed it to them today. Hopefully they will be interested in the idea which is essentially to create a text book which is half theory and half practical, backed up by a dozen or so exercises on a provided DVD. The book is going to be primarily aimed at Media / TV and Film students who often have very little experience in the way of audio production and post production. However, there will also be some more advanced topics which should appear to the more experienced too. My proposed topics include:

• Introduction to soundwaves, signals and metering systems.
• dB theory.
• Studio installation and wiring (to include examples of both audio and video editing setups).
• Location recording: field mixers, field recorders, line up, microphones, synchronisation, cabling and interfacing to both camera and field recorder.
• Specifications: what they mean and how they are measured.
• Digital Audio Theory, including HD.
• Overview of MIDI.
• Dynamics Processors.
• EQ.
• Effects.
• Case study: conversion of a single garage into 5.1 post production studio.
• General introduction and overview of ProTools (and possibly Logic Pro and Apple's Soundtrack too).
• Routing within ProTools.
• Sound for Picture exercise (workflow: capturing Video into Final Cut Pro / Premiere, using ProTools for line up of tracks, editing, encoding video ready for picture edit, exporting audio back out of the NLE after picture edit, back into ProTools for soundtrack mix).
• Listening exercise: demonstration of different microphones used at different distances and recorded to different devices (to DV camera, solid state recorder, via a Field Mixer etc.).
• ADR exercise within ProTools.
• 5.1 in ProTools – in TDM and LE systems.
• Basic mastering.
• DVD Authoring for Audio exercise: stereo, creating and encoding 5.1, adding director’s commentary, PCM and AC3 encoding, basic bit budgeting, DVD scripting.

More on this as and when I hear back.....

Acoustic Panels

After the recent success of designing some acoustic absorption panels for Nottingham City Council, it has now been decided to design and build some for the studio.

Pictures will follow, but the plan is to construct some frames with sloping fronts from 12mm MDF with a 50mm infill of Rockwool. At the deepest points the panels for the wall behind the speakers will be 200mm deep, reducing to 75mm and the ones for the ceiling will be 150mm deep reducing to 75mm. As the panels will be quite deep, there will be a good cavity behind the Rockwool which will hopefully provide good bottom end absorption. Some Cara Acoustic Fabric in dark blue has been ordered to cover the panels with, so they should look quite aesthetically pleasing too.

Construction will begin at the weekend....

Timecode capture / line up in Final Cut Pro

Have just investigated lining up/ capturing separately recorded audio and picture via timecode in FCP.

In the previous post, the idea of jam-synching was touched upon. Basically, the Field Recorder is jam synched (or forced) to adjust its internally generated timecode to that of the camera (or vice versa). Once this has been done, the physical connection between to the two can be removed for at least a couple of hours without drift. This method has the added benefit that the sound recordist is not restricted to being in close proximity to the camera, as no physical link is required (although it can be useful if the sound op wants to monitor sound coming off camera too, for backup purposes etc.). This method only works in FREE RUN (F RUN) mode which is where the timecode progresses regardless of whether the tape is moving or not and means that the two devices do not have to be started and stopped precisely at the same time.

Any way, a Fostex FR-2 was set to generate FREE RUN timecode and then its timecode output was connected to the Timecode input on a Canon XH-G1 camera. Immediately, the camera picked up the timecode and matched it. The cable was then disconnected and both devices carried on generating their own separate timecode, but precisely in time with each other. A small amount of footage was recorded to both camera and field recorder and it was discovered that it helps if the camera is started slightly before and stopped slightly after the field recorder (more on why this is shortly).

Firstly, the wave file recorded by the FR-2 was imported, via USB, to FCP and because of its BWF (Broadcast Wave File) system, the timecode start and stop times immediately appeared in the "Media Start" and "Media End" columns within FCP. Secondly, the "Log and Capture" window within FCP was opened so that the matching footage from the camera could be grabbed. By Option/Dragging the timecode value in the Media Start column into the IN point within the Logging window (and by doing the same for the Media End column too) an exact capture could be carried out by using "Capture Clip". Once complete, the footage and wave file matched perfectly. By letting the camera start before and end after the field recorder, it is easy to get FCP to capture footage between the start and stop times of the wave file from the field recorder. If this wasn't carried out and the camera started after the field recorder, then FCP would not be able to find the required timecode on the tape.

***Addition (Feb 29th 2008) - the last paragraph discussing lining up the separately recorded audio with the picture from the camera, via timecode is not the best method. A much neater method is to use the MAKE MULTICLIP option within FCP and when asked how to align to audio with the video, simply choose MATCH BY TIMECODE. Once this is carried out, FCP will create a multi-clip with the separate audio perfectly aligned to the picture, regardless of whether it was started before or after the camera (the audio attached to the video file from the camera can then easily be removed from the multiclip). This method is also really neat when aligning footage from a multi-camera shoot to audio recorded on a separate device. If a clapperboard was used to aligned the cameras and audio recorder, IN points could be marked on each of the video files (i.e. at the frame where the clapper closes) and then the matching IN point could be marked on the audio file. By SHIFT+clicking on the same audio file with each of the camera angles one at a time and then creating a MULTI-CLIP and selecting ALIGN BY IN POINT, each of the camera angles will now have identical audio attached to them.

Levels and line up

Had the chance this morning to investigate audio levels when recording to a different devices. A Canon XH-G1 camcorder has just been purchased together with a Fostex FR2 with optional timecode board and a Sound Devices 302 field mixer.

The Canon XH-G1 was chosen because, at present, it appears to be the cheapest camcorder available which will both generate and accept timecode synchronisation signals via a standard BNC connection. The idea is to get students to record their audio to both camera and field recorder and to maintain sync between the two via timecode. In some situations, when it is favoured to have the sound operator to be a long way from the camera, the useful feature of jam synching can be used. This feature allows the slave device to force its internally generated timecode to that of the master and then free run without the need for a permanent cable connection (although the cable should be reconnected every few hours to maintain stability). This system only works in FREE RUN mode, which is where the timecode continues progressing whether the tape is moving or not and thus means that the field recorder and camera do not have to be started and stopped exactly at the same time (a useful Flash demonstration of this principle can be found here: http://www.usa.canon.com/app/html/HDV/XHG1/inputs_outputs.shtml (click on the SMPTE TIMECODE section within the large black box). Regardless of physical start and stop times of both the camera and field recorder, the footage required from both will have identical timecode meaning lining up the files in an NLE like Final Cut Pro becomes very easy (see later).

Calibration / Line Up
Some tests were carried out to establish exactly at what level both the camera and field recorder were recording at (as the digital peak level meters can be somewhat inaccurate). The first test was to connect the Sound Devices 302 field mixer directly to the Canon XH-G1 via two standard XLR cables. The 302's attenuation was set to 0, meaning that the 1kHz sine wave it generates is calibrated so that 0 on its bar graph display equates to a level of 0dBu and also provides 20dB headroom beyond this point. The recommendation is to set the input level on the recording device so that 0 on the 302 corresponds to -20dBFS (dB FULL SCALE) on the camera, meaning that +20dB on the 302 corresponds to 0dBFS on the camera, i.e. absolute maximum level.

With the camera's XLR inputs set to LINE and the input gains set to maximum, the 1kHz sine wave input from the 302 was recorded to tape (in DV mode, not HDV). The meter on the camera is very difficult to accurately read as no numbers are provided, however it showed a level of approx. 1 increment below the third division (I said it wasn't that useful). To discover exactly what level was recorded to tape, the footage was captured, via firewire to FCP and then exported to Apple's Soundtrack as its meters are slightly better (although the software itself is pretty useless, but that's another story...). The meters for both channels showed a level of -20.6dBFS which is an extremely useful and useable level. This therefore means that at 0 on the 302's bar graph display, the signal going down onto DV tape was -20.6dBFS, meaning that even if the 302 hit its +20dB segment (maximum) the camera would hit just under 0dBFS, i.e approx. -0.6dBFS.

A second test was carried out, this time using the both the Fostex FR-2 field recorder and camera to record the test signal from the 302. The signal chain was as follows: XLR line outputs on the 302 into the XLR inputs on the Fostex FR-2 (with input set to LINE). The Phono RCA line outputs from the FR-2 were connected into the XLR inputs on the camera and then finally, to monitor the signal level from the camera, its headphone output was input to the monitor return path on the 302. Providing this monitor line from the camera enables the signal to be monitored "post tape / disc". With the same camera settings as previously discussed, and with the input level on the FR-2 carefully adjusted so that it showed the required level of -20dBFS, both the camera and field recorder were set to record. Upon capturing the footage (and copying the wave file from the field recorder). the levels were as follows:

FR-2 LEFT: -18.3dBFS
FR-2 RIGHT: -19.3dBFS

Camera LEFT and RIGHT: approx. -28dBFS

It can therefore be seen that the line outputs on the FR-2 are attenuating the signal slightly and also, its digital meter isn't particularly accurate, giving a reading of -20dBFS for an actual recording level of -18.3dBFS and -19.3dBFS for the left and right channels respectively. It was also difficult to accurately adjust both the left and right input gains to give the same level (as can be seen from the results here). The outputs from the FR-2 are unbalanced, so this might explain the drop in signal level.

As the input gain on the camera was at its maximum setting, there was no way to increase the signal level any further without changing the input sensitivity to the MIC setting. To avoid overdriving the inputs to the camera in this state, the input gains were reduced to minimum and also the camera's ATT (attenutation) function was switched on. Without the ATT button switched in, and even with the input gain at a minimum, the input stage would distort due to overdriving. Gradually the input gains were turned up to give a higher level than what was possible in LINE mode and after a few attempts (which won't be discussed here) it was found that with the camera's meter showing a level of one increment under point number 3, a recording level of around -21dBFS could be achieved; thus allowing 1dB of headroom above the 302's maximum output level.

An alternative method to using the ATT function on the camera, would be to use the 302's built in attenuation mode, however the 302 has a somewhat awkward menu system, so it is probably easier to keep the 302's output level at its default of 0 = 0dBu.

Photosynth Demo

This is nothing to do with audio, but I had to include it in this Blog as it is extremely impressive:

Quote: "Using photos of oft-snapped subjects (like Notre Dame) scraped from around the Web, Photosynth (based on Seadragon technology) creates breathtaking multidimensional spaces with zoom and navigation features that outstrip all expectation. Its architect, Blaise Aguera y Arcas, shows it off in this standing-ovation demo. Curious about that speck in corner? Dive into a freefall and watch as the speck becomes a gargoyle. With an unpleasant grimace. And an ant-sized chip in its lower left molar. "Perhaps the most amazing demo I've seen this year," wrote Ethan Zuckerman, after TED2007. Indeed, Photosynth might utterly transform the way we manipulate and experience digital images."

Reverbent Office - update 1

One of the prototype absorption panels was tested in the office space today. However, at 3m tall by 2m wide, it was a little on the large side. On the plus side, a very noticeable reduction in reverb time was observed and so now, after some detailed calculations using the Sabine formula and assuming a nominal frequency of 1kHz, it has now been decided to make 12 1200 x 600 panels based on the same design as in the previous post. Assuming the maths is correct, the calculated RT60 time of 1.65s should be reduced to around 0.65s with the panels in place; Howard (2006), states that this is an ideal figure for speech.

Ref:

Howard, D (2006). Acoustics and Psychoacoustics, Oxford, Focal Press.

Noisy Office

Visited an office at Nottingham City Council this week. The office in question is extremely reverberant due to the high ceiling, bare plastered walls and lack of any absorption. The two options were either to reduce the volume by installing some kind of suspended ceiling or to increase the room's absorption characteristics. The latter option was favoured as the room itself is very ornate with detailed coving surrounding the ceiling, so it would be a shame to get rid of this.

As a result, I came up with a prototype absorption panel (based on Paul White's design) to be built and tested. If a satisfactory result is obtained the final solution will be to fix half a dozen or so around the office walls with high resolution photographs of Nottingham screen printed on to the fabric covering.

Text book anyone?

Have been in contact with Focal Press about me writing a text book on Audio Production / Technology / Post Production type bits. I want to create a "one stop" solution for people new to the world of audio, from background theory (but not too technical) to providing lots of hands on tutorials with accompanying CD/DVD. I have written lots of handouts / handbooks during the past few years and I now think it's time to try and get them out there.

There's lots of excellent books in the Focal Press range, but I want one which covers bits of everything and one which hopefully will enable students to see the importance of learning the theory as well as the practical.

Session

Feeling very good at the moment to actually be using the studio. A new song which we have recently started is really starting to take shape and it's so good just to be able to send people to the vocal booth and to obtain extremely clean recordings without the usual PC fan noise in the background.....

On a separate note, just about to put an order in for Final Cut Studio 2. Having never really used Final Cut / DVD Studio etc., properly before, it is going to be nice to have a play with them. The new COLOUR package looks awesome for giving signature colour grading to projects (I especially like the look of Top Gear at the moment). It also contains Soundtrack Pro - not sure what that's like?

BBC Radio Drama

Forgot about this one - a month or so ago I went to a guest Lecture by Connor Lennon, who is a radio Producer for the BBC. He is wanting people to produce short, 3 minute, radio dramas with a view to making radio drama more popular. What with podcasts and audio on the move in general becoming ever more popular, Connor believes that radio drama could be the next big thing.

Not something that I have done before, I think I will have a go at producing something in the studio.

Connor's blog is here: http://audiodrama.blogspot.com

Here are a few more images showing the Vocal Booth......

Another session a success

Wednesday 28th Feb saw a second a session take place without any hiccups. Mark, my guitarist just fitted inside the booth with his acoustic guitar in tow (forgot to take any pictures though).

A new feature was discovered in ProTools too whilst editing / comping Mark's guitar takes. Beat Detective (CONTROL + 8 on numeric keypad), is used for things such as analysing tracks and splitting them up into multiple regions around each significant transient (each drum beat for example). However, it also contains a feature which will "fill in the gaps" around each edit and auotmatically create fades and crossfades to ensure a seamless cut. Mark's timing was a little off during the intro of the new song, so using the "separate region" command (keyfocus + B), the chords were separated and then aligned back to the grid. Then, using the feature outlined above in Beat Detective, the gaps created due to this editing were seamlessly joined back together; I will post some screenshots soon.

Another feature used during some vocal takes with Ollie, was the "matching start times takes list". As well as being able to use this to comp a single vocal track within itself, I discovered that the different takes can easily be layered upon each other by using multiple tracks. This therefore allows complex multi-tracking of harmonies etc., to be very quickly layered by using a combination of this and the loop record feature.

Bass traps etc.

It can be seen in the previous post that minimal treatment has been applied at this stage. Three wedge tiles were left over from the booth, so these have been positioned behind the three front monitors. However, it is hoped, when funds allow(!) to apply a few more to the rear wall and ceiling and also to incorporate a bass trap in each corner. The bass traps will either be off the shelf from the same place as the tiles were purchased from, or they may be made following Paul White's design in SOS - (based around a 125mm deep wooden frame, wedge tile on top and rockwool insulation behind) - chec out http://www.soundonsound.com/sos/jul06/articles/studiosos_0706.htm for further information.

Photographs

Today, my brother very kindly came round to take some photographs using his very expensive digital SLR :-). I hope to use some of these in my new website. Shown here are a few of the ¨proof¨ pictures.

I especially like the one in the Booth - shot with the camera sat on the floor.

First session a success

Friday 23rd February saw the first session in the new studio. The session consisted of writing a new song together with laying down some basic rhythm guitar (routed live through Amplitube LE in ProTools) and some guide vocals. I played around the following day adding some string parts and basic percussion. This was a basic session, but it was really nice to actually USE the space at last!