Songs From The Wood

We’re big rock fans here at Digit, and we’re borderline obsessive-compulsive when it comes to the way our music sounds. We want guitars to gently weep, cymbals to crash just so, and drums that would rock the Casbah; “compromise” is a word whose use we don’t condone. Perhaps that’s why you will often find us trying new and strange ways to tweak and position our speakers-yes, even paltry two-speaker systems-in our quest for the ultimate music experience.

Sometime during said quest for perfect audio, we wondered how sound engineers at big concerts manage to keep thousands of people happily bouncing away to the sound of their favourite bands, and it boggled the mind.

And then we heard that Jethro Tull-one of the greatest rock bands of all time-was performing in Mumbai on January 31.
Hmm…how convenient.

“Just Don’t Trip Over Anything”
So we endeared ourselves to the guys at sound.com (see box sound.com)-the sound engineers and audio equipment suppliers for the concert-and convinced them to let us tag along as they went about weaving their magic.

We inflicted ourselves upon Sunil Karanjikar, systems/mix engineer at sound.com, who was our guide in this magical journey through a strange and wonderful mix of wires, musical instruments and mysterious odours at the Shanmukhananda Hall in Mumbai. Sunil is quite obviously the electronics geek-his face lit up as he told us about frequency responses, noise gates, power distributions and signal processing.

On the morning of the concert, our heroes were already bleary-eyed from a night of setting up the huge speaker rigs, guided by the JBL Line Array Calculator-an Excel sheet provided by the manufacturer of the speakers-which suggests a starting point for their setup, based on the dimensions of the hall.

Men At Work
Shanmukhananda is an auditorium with three levels, and the first order of the day is to ensure that the sound reaches all parts of the hall-which is why the speakers arch upward. High sound frequencies are more directional than lower frequencies, so while they don’t have to worry much about the bass, they do need to ensure that everyone gets the full effect of the highs.

To make sure the sound reaches its intended recipients, the gang uses a somewhat crude but useful tool-the laser pointer. “This way, we at least know that the speakers are pointing towards the people and not the wall or ceiling.”

We wondered about the speakers lining the front of the stage. “Those are for the people in the front rows. The speaker arrays at the side will have their effect only from the fourth or fifth row, so without these, all that the front rows would hear is bass”, Sunil explains.

Next step: getting the music to the back rows without having to blow out the ears of people in the front. You deserve the best sound even if you were a cheapskate with the tickets, so there is a set of speakers towards the end of the hall to make sure you get it.

Interlude-The Heart
In the thick of the action is the XTA DP428 Audio Management System-a Digital Signal Processor (DSP) whose responsibility it is to send the right frequencies of sound to the right speakers-splitting the sound into bass, mids, and high frequencies. A seemingly simple task, but as Sunil explains, “Lower frequencies tend to move speaker cones a lot, so bass must go to the bigger, heavier speakers built to handle this movement.” And what happens if we were to try playing bass through the other, lighter speakers? “They’d blow up…” Clearly not a fitting end to crores worth of equipment.

The DSP also adjusts sound volumes in such a way that speakers meant for the front of the hall deliver a softer sound than the speakers meant for the back. This is called Amplitude Shading, and this is why your head doesn’t explode when you’re in the first row. To control all these settings, the sound.com guys use Audio Core-XTA’s own software designed to work with the DSPs they manufacture.

Even with better technology, nothing sounds as good as the older vacuum-tube guitar amps. We actually use one that was built in 1959!”
Sunil Karanjikar, Systems/Mix Engineer,SOUND.COM

To analyse the sound in the hall, they use SIA’s SmaartLive, which measures the difference between the sound that is supposed to come out of the speakers (the electric signal sent to it from the DSP) and the sound that actually does. SmaartLive and Audio Core interact with each other, so when SmaartLive detects any problems with the sound, Audio Core can be used to compensate.

An Equal Music
Now that the speakers were positioned, and everyone was convinced they weren’t going to topple over and kill innocent people, it was time to configure them for the Ultimate Music Experience we keep hankering after.

These speakers at the front of the stage ensure that the front rows aren’t left out

The first hindrance to the said experience is the fact that sound travels slowly, so if you happen to be towards the end of the hall, you’re first going to hear the sound from the second set of speakers we mentioned, and then, albeit softer, you’re going to hear the sound that came from the speakers at the front of the hall. Up front, too, you’ll face a similar situation-you’ll first hear the sound from the speakers, and then from the instruments themselves-all extremely unpleasant. To get around this, Audio Core delays the sound going to all the speakers so that all sounds hit your ears at the same time. 

We took a trip to the back to see this in action, and sure enough, we first heard a drum beat from the speaker closest to us, quickly followed by another from the speakers close to the stage-a decidedly unpleasant echo, echo, echo… Put simply, if you say the infamous “Mic Check, one, two, three,” the audience at the back would hear, “Mic(Mic) check(check) one(one), two(two), thr(th)ee(ree)”. And it sounds worse than it looks, too.

There was a microphone near the speakers at the stage, and another next to the second set near the end of the hall, and they recorded the time it took for sound to travel from the stage to the back. This information was then fed to Audio Core, and soon enough, the delay was adjusted to the point where we couldn’t tell the difference between the two speakers.

Having now satisfied themselves that nobody in the audience would be disappointed, the time had come for the gentlemen to start setting the stage for the concert.

“Lower frequencies tend to move speaker cones a lot, so bass must go to the bigger, heavier speakers built to handle this movement”

Stick To The Plan
“What’s the big deal?” we asked when we witnessed some animated discussions and a few profuse apologies involving last-minute changes to the stage plan.

As Sunil put it, “Audio is a funny thing. See that curtain there?” (We did.) “If they were to open it or close it a little more, the sound we hear is going to change, and we’ll have to adjust the setup even for small things like that. Instruments also sound different the moment we change their positions, so we need to fix a stage plan in advance.”

It isn’t just the audience-the artists need to hear themselves play as well, and “monitor” speakers are set up where they’re supposed to stand. These can give a monitor engineer (the guy controlling the monitors) some memorable nightmares-if the band’s microphones were to get too close to the monitor, sound from the speakers would enter the microphones, come out of the speakers, re-enter the microphone, come out of the speakers again…this is a deadly loop, and creates the horrible whine called feedback.

The Crown ITech amplifier powers all the speakers

And if you think that’s not complicated enough, rock guitarists use feedback to enhance their playing style and get some weird sounds-so not only do the guys have to make sure that microphones don’t, they also have to make sure that the guitars do provide feedback when required.

“More artists today are starting to prefer in-ear monitors, so there’s no chance of feedback there”, says Sunil with an unmistakable sigh of relief, “and almost no Indian classical musician uses a monitor at all-they just work off the sound that the audience hears.”

With separate speakers for the audience and the artists, it stands to reason that there would be two different people to cater to them-the Front Of House (FOH) engineer sits at, well, the front of the “house” (that’s hall, auditorium or stadium to the rest of us), and hears what the audience hears. It’s his job to ensure that everything is just so for the audience.

For their own needs, the artists turn to the monitor engineer, conveniently located near the stage, who will tweak the sound in their monitor speakers-even right in the middle of a song!

One By One
As the band begins to trickle in, blood pressures run high as everyone runs around making sure everything is ready for the Moment of Truth-the Sound Check.

We were a tad taken aback when Sunil whipped out a Tablet PC, a microphone, and a Wi-Fi router at this point. “All the equipment-the amplifiers, the signal processors-can be controlled over a standard Ethernet connection, so we can adjust the output from anywhere in the hall”, he says. They spoke of it with cool nonchalance, boredom even, while we were replacing our eyes in their sockets and wiping the drool that had begun to show.

The Midas Verona 48 Input Mixing Console at the Front of House to ensure the audience gets the best possible sound

So while the band played their instruments (first one at a time and then all together), Sunil did the rounds of the hall, using SmaartLive to measure the sound output at different locations and then using his Tablet PC to remotely change settings in Audio Core.

The band continued to practise for a while, for the benefit of the FOH engineers who kept monitoring the sound so that the audience is kept happy, and for the monitor engineers, who can then learn the artists’ preferences.

So is it all about technology? “The human ear does play a very important role in the whole process-even with all the measurements, it has the final say in how the system sounds”, Sunil tells us.

On a tangent, watching and listening to a band practise before a concert can be a whole lot better than the concert itself, and is an experience that’s highly recommended by this writer.

Even something as seemingly harmless as the audience’s entry into the hall can change the sound

Showtime!
In a startling show of fortitude, we were still able to watch the technology even while one of our favourite bands was playing on stage. We’d thought that now that the sound had been adjusted over and over again, even the engineers could sit back and enjoy the music. Apparently not.

The Klark Teknik graphic equaliser for the Monitor Engineer to cut out feedback, if any, from the performers’ monitor speakers

Even something as seemingly harmless as the audience’s entry into the hall can change the sound, so the guys still have to keep monitoring the sound quality and changing settings from time to time.

Thanks to the day’s efforts, the audience was happy, the band was happy, we were happy, and a good time was had by all. The satisfaction and relief on everyone’s face just spoke for itself.

Endnote
Don’t tell anyone, but all we really wanted was an excuse to spend the day at the concert (free), and still get our daily bread. As it turns out, there’s a lot more to setting up a concert than just a few good speakers and a ear for sound. As an observer, you need to fortify yourself against scary-sounding terms such as frequency responses, signal conditioning, electro-acoustics, low-pass filters… you get the picture. This writer would probably have fallen asleep with all the electronics jargon if he hadn’t paid attention in class those few years ago.

The guys at sound.com probably breakfast on transistors and capacitors (they may not admit this, though) and make light snacks of ICs. The most difficult question we could possibly ask them? “Do you love electronics more, or music?”

We thank sound.com for putting up with our constant harassment, especially Sunil, who was always happy to answer questions even at the busiest times during the show! We would also like to thank Tower of Power and Only Much Louder-the organisers of the show-for permitting us to descend upon the venue. And finally, Jethro Tull and Alms for Shanti. For the music.

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