Better Film Sound

A forum to share ideas and opinions on the equipment and technical aspects of film, video and AV making.
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Peter Copestake
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Better Film Sound

Post by Peter Copestake » Wed Oct 25, 2017 9:42 am

In his article in FVM James Chalmers says - "Don't have music tracks running above -12Db ..." ie well below the -6Db he recommends for voice.
Does this mean that music sounds louder than the same technical level of voice? It always seems to my ears that TV music is always louder than voice even, often, when on at the same time which is why I find dialogue hard to follow. james gives a different reason for this, to do with quality of TV speakers, but, rightly, I think, says other sound levels should be kept as low as possible under speech.

My latest film has a brief, sharp, repeated percussion live sound on a sequence on the track that peaks very briefly at 0Db on the tape deck I use to channel picture and sound to a TV/amp monitor. No one has criticized this and it seems not to hurt ears. Any comments on this?
Peter Copestake

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Dave Watterson
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Re: Better Film Sound

Post by Dave Watterson » Wed Oct 25, 2017 1:28 pm

I hope that someone like John Roberts or Alan Colegrave will comment, since they have far more knowledge of sound technicalities than I do.

My only contribution is that we must depend on human ears ... our own, or if we know we have hearing deficiences, the ears of trusted friends.

John Roberts
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Re: Better Film Sound

Post by John Roberts » Wed Oct 25, 2017 3:50 pm

Dave Watterson wrote:I hope that someone like John Roberts or Alan Colegrave will comment, since they have far more knowledge of sound technicalities than I do.
I had already started a response, but unfortunately had to leave off to go and do some filming! :shock: :shock: :shock: :lol:

tom hardwick
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Re: Better Film Sound

Post by tom hardwick » Fri Oct 27, 2017 6:45 am

I'm a believer in monitoring the audio mix from loudspeakers rather than headphones, finding that the intimacy of headphone listening can make me have the background sounds set too high Vs the dialogue.

So I use loudspeakers on my timeline and for quick tests output a section of the timeline as a short mp4 file to usb stick. This plugs straight into my TV and gives me instant audio feedback in the real world.

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TimStannard
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Re: Better Film Sound

Post by TimStannard » Fri Oct 27, 2017 8:36 am

Couldn't agree more, Tom. On the other hard headphones are great for cleaning up audio before putting it into the mix. Often I'll watch (listen) to a film which might not sound as clear as it might - if I listen through headphones I can the identify the source more clearly - very often background hiss but frequently artifacts due to over enthusiastic application of Noise Reduction.
The other audio sins that headphones help highlight are harsh audio cuts and poor stereo imaging.

In a nutshell, you need to monitor audio on as many different devices as possible.

Whilst I await John's more authoritative treatise, I believe the simple answer to Peter's question is that music tends to have a more constant level whereas dialog has a greater apparent dynamic range and it's the constant level that makes music seem louder. Adverts use compression to bring up the quieter levels which is why, although still within the broadcast standards, they often seem louder than the programmes either side.
Tim
Proud to be an amateur film maker - I do it for the love of it

tom hardwick
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Re: Better Film Sound

Post by tom hardwick » Fri Oct 27, 2017 8:54 am

Very good point you make about using headphones for the critical analysis of the audio track. So many films I've seen have had the audio sound f/x only on one channel, yet the filmmaker has been completely unaware of the this.

Peter Copestake
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Re: Better Film Sound

Post by Peter Copestake » Fri Oct 27, 2017 10:03 am

Thanks for all comments so far which haven't mentioned the technical "fault" of sharp sound going above -6Db except for Dave saying 'depend on ears'. I'm glad of that, ina way, as I know that Dave doesn't judge films on poor quality TV speakers and he might get to see the film in question!
Our club speakers reveal wind rumble that I have't been aware of, though I use good quality headphones as well as half-decent speakers - at different times!
Best value wind muffs for lavalier mics, anyone?
Peter.
Peter Copestake

John Roberts
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Re: Better Film Sound

Post by John Roberts » Fri Oct 27, 2017 10:44 am

TimStannard wrote:Whilst I await John's more authoritative treatise...
I can waffle on about this for hours LOL :lol:

In reply to Peter's original query, and in defence of James Chalmers's 'Suggestions for better film sound' articles - audio is as much of a dark art as video!

I find it incredibly hard to generalise when talking about the relative level of musical balance because there are too many factors at play. Chief amongst these are the almost useless 'peak' style audio meters that most editing suites use; they are useful for only one thing and that is to ensure the audio level doesn't exceed 0dB and cause digital clipping. Peak meters are useless when trying to ascertain the loudness of a particular soundtrack although they can be used as a guide if you know how to interpret them correctly. Secondly, the style and energy a musical track might possess will vary wildly, for example your short, sharp percussive track will hold less average or RMS energy than say a heavy rock or metal song. If both were played back at the same peak level on your editor's audio meters the apparent volume of sound would be quite different. A lot of this is to do with the compression of music and in days of old all major broadcasters would recommend a different PPM level for different degrees of compression a musical track might have been subjected to. The more a track is compressed, the louder it appears at the same indicated maximum peak level because a compressed music track will have had its peaks squashed, therefore increasing the average energy of the music.

It can be useful to apply a level of compression to a narrative track as well, and this can help the sound balance no end. Chopping off those occasional peaks from a voiceover is as useful as applying compression to music because it can compress the dynamic range of the voiceover, avoid those peak meters from clipping (which will almost certainly cause the editor to reduce the entire volume of the voiceover track downwards) and can stop the projectionist reaching for the volume control when the occasional word or phrase appears too loud. Getting the right level of compression can take time, but once set up correctly can be very effective indeed.

Both Tom and Tim make very valid points about monitoring audio as well - both headphones and speakers should be used for the reasons given, then a final mix checked on the TV, although if the mix sounds right on a properly set up editing system the final TV check should be just a courtesy: I gave up checking on the TV years ago. Currently I switch between a pair of Sony MDR-7506 closed-back headphones (almost the 'industry standard') and a pair of JBL Professional LSR305 digitally self-powered monitors, which have a frequency response flatter than a hedgehog on the M1. Both these items, although affordable at around £300 for the lot (much less than the cost of a camcorder or even a decent DSLR lens!) are incredibly highly rated amongst the industry.

One other often neglected practice is to occasionally, or as much as you would like, watch commercial films and documentaries on the same system you are editing on. I rarely watch TV because 95% of the films, box sets and downloads I watch are played back via the same monitor and sound system in my studio. I have therefore 'conditioned' my eyes and ears to how professionally edited productions look and sound on my system, therefore I cannot help but to unconsciously try and make mine look and sound the same.

Trust your ears, Peter - as long as your ears are interpreting the right thing! :D

I hope this tome helps :lol:

John

PS: Peter, re my "as long as your ears are interpreting the right thing" line and in reference to your post that snuck in mentioning that your club system is revealing wind rumble that your aren't aware of, tells me that your monitoring system is not good enough although your ears probably are. If you can hear wind rumble at the club but not in your editing suite - why not? I suspect the speakers you are using do not have sufficient low frequency capabilities. Remember also that you need to monitor at a reasonable sound level (for the techies amongst you that is around 83-85dB: loud enough to be comfortable but not enough to cause hearing damage) so having a 'whisper quiet' decent monitoring system is as ineffectual as having a rubbish one!

Off to do some more filming but will check back later :)

Peter Copestake
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Re: Better Film Sound

Post by Peter Copestake » Fri Oct 27, 2017 11:42 am

re John's PS: Yes, indeed, why not? I think that the sound system at the club is usually at a higher volume level level than I ever use at home, even with headphones, as we live in a quiet house and my wife has hyperacusis and very sensitive to bass, especially, so we never have TV or player volumes up to levels some people would regard as normal. For the same reason we haven't been to cinema or organ-playing church for decades. Fortunately we are Quakers anyway!
And thank you, John, the rest of your mail is very helpful. My headphones are early model Direct Sound - Extreme Isolation, so I can use low volume with those too.
Peter.
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TimStannard
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Re: Better Film Sound

Post by TimStannard » Sat Oct 28, 2017 11:33 am

John Roberts wrote: I can waffle on about this for hours LOL :lol:
Depending upon who is doing the waffling and whether they know what they are talking about this can be a good or a bad thing. In this case it was a good waffle!
Tim
Proud to be an amateur film maker - I do it for the love of it

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