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Audio Technology | How To's | Tips -

Diffraction Explained

Soundwaves are vibrations of molecules in the air that cause pressure variations. When these waves encounter an obstacle, or any change in the surface or medium they are traveling within, they will try to bend around the obstacle. In a sense, they distort from their original form.

Think of the surface tension that causes water droplets to collect on a leaf. The edge of the leaf is a change in surface that causes the water to slow down and change form. But now surface tension of the leaf won’t let it continue their journey to the ground so more and more water gathers until the force of the weight of the water is greater than the surface tension. At this point the water, now in the form of a droplet, falls from the leaf.

Now think of soundwaves leaving your loudspeaker cabinet. Sound energy behaves similarly to water – as the sound reaches an obstacle, in this case the edge of the speaker baffle, it tends to slow down and change shape until it leaves the surface of the baffle and jumps out into the air around it.

The problem with that little bit of physics is the sound energy now leaving the baffle is delayed from the original sound it left the speaker with. That original sound has already hit your ears, but now this delayed sound hits your ears with sound information that can be several milliseconds behind the sound it started off with. This delayed sound interferes with the current sound causing smearing which muddies up the quality of the sound. Your brain can’t differentiate different sounds that are so close together, but it knows something isn’t right, so it winds up processing the sound as a distorted jumble of noise. Even if this distortion is very slight, it still changes the sound of the original. In cases where the smearing is extensive, it can completely change what we hear (and not for the better).

Our engineers have come up with two really elegant solutions to this seemingly intractable problem and the results are an amazingly clear and precise soundstage that develops because the sound you want now isn’t competing with remnants of the sound you wanted a few milliseconds ago.

The first solution is found in our family of LS products – now you know why the front baffle is curved, to reduce diffraction. The curved front baffle creates a nearly infinite number of surface edges for the sound to travel over. After confronting all of these “edges” on the curved baffle, by the time the sound energy leaves the loudspeaker it is so out of energy it never makes it to your ears. We can’t eliminate this law of physics – diffraction is going to occur whether we want it to or not – but we can reduce it to the point of elimination relative to your ears.

With a traditional loudspeaker shape such as our Reference and R Series products, a curved baffle is simply not feasible – the box would be way too large and unappealing to the eye. Once again, our engineers came up with an elegant solution that is super simple (all the good problem solutions are usually the simplest ones) – they made the cabinets as narrow as possible so that the cabinet isn’t much wider than the bass drivers. They solved the problem of the Uni-Q drivers being smaller than the bass drivers through the Shadow Flare, which is basically an extended waveguide for the Uni-Q that leaves less surface area for the sound energy to gather on. In short, we made the Uni-Q driver “appear” to the sound energy as if it is not much narrower than the cabinet.

It all started with the iconic design of Concept Blade and has since been passed down through the rest of our product line. These two simple solutions to one of the audio industry’s biggest impediments to accurate sound reproduction were solved by taking a good old-fashioned engineering approach to the problem. Now go and enjoy what music sounds like when its not being spoiled by the laws of physics!

If you haven't heard what musi (or movies) can sound like when diffraction is no longer an issue, do yourself a favor and book a Reference, Blade, R Series or LS family demo today!

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