Inside-The-Shop

Inside-the-Shop are informative articles written by Kevin Smith, Luthier of The Violin Shop

The Violin Shop

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Room Acoustics

About 25 years ago I stood in the middle of St. Paul’s Cathedral in London. Dwarfed under its 365 ft. high dome set on a colonnaded drum, I looked up. The enormity altered my spatial awareness, taking my breath away like the first plunge of a long freefall.

I don’t know if Sir Christopher Wren knew what he was doing acoustically when he designed and started rebuilding it in 1710, some 44 years after the Great Fire took the original cathedral. But the Portland Stone construction (very compact sandstone) absorbs almost none of the sound inside the building. I stood there, gasping as I looked up in the company of immaculate woodcarvings and master iron works, listening to the whispers, hushed conversations, and echoing footsteps scattered around the cathedral. The acoustical enormity was as intense as the spatial enormity. And I felt awe.

Sound, like sight, is so easy to take for granted until moments like that. Most of the time we hardly know we see and hear. We just do it. We pick up our instruments, love the music we play, and give homage to those who wrote it. It’s not often we think about how it reaches our ears, even though it can alter our judgment of any given instrument enormously.

So the next time you pick up your instrument to play, take a look around you. Look at the room you’re in. It plays a huge roll in the quality of sound that you hear. The size of the room, what’s in it, how many windows it has, what it’s made from.

In his book “Music, the Brain, and Ecstasy,” Robert Jourdain talks a little about acoustic surroundings. He mentions (I’m paraphrasing) “how carpet absorbs high frequencies but reflects low frequencies. A glass window absorbs the low and reflects the high. Poured concrete or polished stone absorbs almost no sound at any frequency. But Human bodies soak up full two thirds of the sound striking them. Even the air plays a roll in damping the high frequency reverberations.”

This makes things interesting. You can tune a room like you tune your violin, viola or cello. For instance, if your cello has a harsh edge to the sound and your room has a wooden floor, buy a rug. It will absorb some of the harsh higher frequencies while reflecting the lower ones. If it’s muddy sounding, get rid of the carpet and open the curtains covering your windows.

Mr. Jourdain goes on to talk about three main kinds of sound we perceive. There is direct sound, which we hear directly from the source. There is first reflection, a close range sound bounce (walls, ceilings, etc. that are within 20 feet or so) ideally lagging about 1/50th of a second behind direct sound. And there is reverberation, a delay ideal at 1 second, but can last up to 2 full seconds.

If you want to understand the “tuning” of a room, this is important stuff.

The brain, in its drive to make sense of the world, combines direct sound and first reflections. And the better the first reflections are, the warmer and more intimately you hear the room.

This is very useful for anyone trying to sell instruments. And it’s one of the reasons you need to take instruments home to try in your “own acoustics.”

But if you ever go to a violin shop with a great tryout room, take a look around. There are some masterful rooms, skillfully assembled, that can teach you a lot. The wooden floor with an oriental rug is not just ornate. It’s technical. The rug will absorb the high frequencies from below, giving back the lower ones. But the wooden floor exposed around the edge will send back faster, higher frequencies, enhancing the fuller sound you hear through first reflections.

Take a look at the furniture. Is it leather in one area and a plush fabric in another? Is there a piano giving sympathetic complexity to the sound of the room? It starts to add up.

A couple of oil paintings on the main wall will reflect back mid range frequencies. Some art behind glass off to the sides and in the corners will increase high range first reflections, as will windows. Windows with curtains are great because you’ll get first reflections with frequency differences from the same area. And if you have a part of the room that’s dead sounding, a piece of sculpture made of stone or bronze will bring it vibrancy.

The possibilities are endless. And you’ll see a lot of different arrangements of well-tuned rooms in violin shops around the world.

Now don’t get me wrong. Every violin shop should strive to have at least one room tuned as well as they can. You want to hear instruments in there best surroundings. But don’t depend on that room for your final judgment. Use it to find the best instrument in the group, then take it home and play it in your own “natural” surroundings. Play it for a week in as many different environments as you can, compare it to other instruments, and then make your decision.

But whether you’re in a violin shop, a concert hall, or in your living room, a well-tuned room is one of the subtle pleasures that elevate life to greatness. The kind of pleasure harnessed in the cathedral of sound we live in.

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