Readers' Letters: What are the best ways in getting a good gain structure in a live concert mix?, and more...

David Mellor

David Mellor is CEO and Course Director of Audio Masterclass. David has designed courses in audio education and training since 1986 and is the publisher and principal writer of

Thursday November 30, 2006

In response to What are the best ways in getting a good gain structure in a live concert mix?, Efthimis Tikellis writes...

Allow me to tell my humble opinion about gain structure for live events. As you already mentioned live sound is much trickier than studio sound, and the main reason for that is the fact that we reproduce the sound through speakers in the same environment with our sources. As a result things like the source and speaker placement as well as the acoustics of the environment have a great effect on the sound.

Now, in studio conditions all we do is press PFL and start increasing the gain until the meters go up or near to 0dB on our mixer. By pressing PFL we bypass the fader which means that it is exactly the same thing as if the fader was on 0dB since we do not attenuate or amplify the signal using the fader. That means that after you adjust the gain using the PFL, you can take the fader up to 0dB and there you have the so called 'unity gain'.

However in a live event that is not the case, because of the reasons mentioned in the first paragraph. Since the majority of live events do not take place in the ideal venues, most of the times, depending on the acoustics and the placements, if you adjust the gain using PFL and then try to take the fader up to 0dB you going to get feedback. I've seen many engineers doing it this way and then taking the faders up to a point that nothing feeds back, but it's always lower than 0dB.

Before I start explaining why I believe this not the best way to do it, we need to realize that the gain on a mixing console is actually a pre-amplifier. And pre-amplifiers are noisy devices by nature. Of course that varies with quality and price.

When we increase the gain we amplify the signal and with that we amplify the noise. Now, there is nothing wrong with that; there is nothing we can do since that's how pre-amps work.

By using the PFL to adjust the gain in a live event you allow the maximum acceptable signal in your channel-strip and all the noise that comes with it. Then by keeping your fader lower than 0dB not because you want to but because you cannot go any higher, you attenuate the signal and your noise but it's too late now. The noise is already there. You let it come down your channel-strip. And not only that, but you eliminated any headroom you had. Later when you will need to mix the sources you won't have that much space to move your fader. There comes the rule that states that 'the less you move your fader further than 0dB the better'.

What I use to do is actually use my EARS to listen to the sound instead of my EYES to look at the meters. Forget PFL and take your stereo mix faders to 0dB. Do the same with the fader on the actual channel and then start increasing the gain up to the point that you can hear the sound clear and loud without any feedback (that point will be lower than the point of the first case, which means that you amplify the signal and the noise less than the first case because you do not need to amplify it more, which is GOOD). That is the 'unity gain' for this case and set-up. When you finish adjusting the gain for all your sources, you will end up having all your faders at 0dB and plenty of space to move your faders up or down for mixing. And even after mixing the faders will not be that far from 0dB.

That of course is my opinion and I'm not the person that says what is wrong and what is right. I apologize for writing in such a detail but I consider gain structure to be one of the most important issues in sound engineering. Please let me know if you have a different opinion or any comments on this article.

Thanks for reading

Efthimis Tikellis

RP response: Also, if an instrument is going to be at a low level in the mix, it can be more convenient to set a low gain so that the fader can be higher up in its travel and easier to operate.

In response to "Foolin" by West of Texas, Bill Kinnamon writes...

West of Texas has a great sound. The guy knows his stuff, musically, as well as technically.

In response to Can you use studio mics for live sound?, Frank De Pellette writes...

Interesting question. I used to engineer outside broadcasts for an F.M. radio station.

On a few occasions, I experimented by substituting our presesenters (the talent) SM58's for Beyer 201's.

I have to admit that I love the 201's crisp, clear, colour free sound - unique for a dynamic mic, and it's hard to get anything less than good results from it when it's used in the studio with voice or instruments. On the other hand though, being fed through a P.A. and also to a studio for transmission, makes it sound thin and reedy, lacking any punch - and it pops on everything regardless of windshield use. Conversely the SM58 sounds, to my ears at any rate, boxy, muffled and lacking at both ends when used for voice broadcast - yet it's live performance is very good. And it doesn't wilt easily...

So - any explanations David ?

RP response: I was once talking to a BBC engineer about why they used ribbon mics for their World Service radio broadcasts, where the signal needs to travel hundreds or thousands of miles. Apparently the signal was simply more intelligible at the other end. It's very subjective and extremely hard to measure these effects. The Beyer M201 is a great mic, by the way, unfortunately often ignored. DM

In response to Why isn't your music making any money?, J-Hoon Balbuena writes...

I love the article on the reality of music and money. Especially when free downloads are so rampant these days, CD sales in so many countries have dropped and been jeopardized. Musicians everywhere are concerned about the overall future. This is a result of technology and consumerism. This is really simple logic, why would I wanna pay if I can acquire the material for free???

Does that mean the profit of music has really come to a demise since there is an OVER SUPPLY of music? See the article seems to focus on our choice in music simply because of quantity and alternatives, BUT I beg to differ if a song can get your attention in a simple preview and give you goosebumps. To be honest, people will definitely PAY for quality music. So the questions lies NOT in the existing traffic of the internet and how restricted profit can be within this system, but how we can manipulate the traffic and the large audience into profits that would come from other sources

Case and point, when John Mayer was uploading his own tracks while thinking about dropping out of Berklee, people did not abandon him simply there was so many other options. HIS SONGS and MELODIES differentiated himself. Money came after the buz he created online that lead to major recording deals. The golden rule remains, be it rock / hip hop / country / heavy industrial techno......a hooky song is a hook song that sticks. And when it carries that quality of hooky and concise message. You are good to go!!! So its still goo music that counts.

For me the internet is like a test ground that leads to bigger things. The fact remains and as a I said, a nice piece of music will hit wherever you put it. Internet distribution should not be seen as an end to the circulation of profit, albeit the cash can be a quite little from the net but if you had already generated a million hits from myspace or whatever online labels there are. Then you can basically elevate these figures into the real life platform and earn millions from endorsements / ring tone / publishing etc.

As I mentionedm, number of HITS or DOWNLOADS are a solid testimonial to telecom (ring-tone era), record labels and just any CORPORATE that is in search of leverages for their products. When you expand your angle into linking THE INTERNET and the physical companies everywhere. Millions of money are probably just a few steps further if your message goes with their next marketing campaign. Who says you can't make millions from music?>??

With a good song thats hooky and carries a message that's universal, a good manager and a good connection of companies and ad agencies. Your music will sell. Mark my word

Much love


In response to Piracy made legal - how will *you* benefit?, John Tumminello writes...

Copyright... Here's something that needs updating. We need copyright to protect those with the talent. The laws just need to be updated to push harder penalties to those who steal or sell music illegally around the world. The problem as far as I can tell is that people hear music for free in so many places, the mall, the car, the office (they forget all that music was paid for) that they think it all should be free.

When a teenager hears their favorite song in the car or mall for free they don't relize that radio or the mall paid for that music to be played. People hear all day long so much music for free they become fooled into thinking it all should be free all the time. Just my opinion.

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