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In Reply to: RE: Maybe you place to much importance in diffraction ? posted by Mike B. on July 03, 2012 at 15:43:20
I don't think you can place too much emphasis on diffraction, and the effects are quite audible and show up quite readily in a frequency-response chart of sufficient resolution.
Good designers are addressing it in speakers that cost a few hundred buck. For thousands, tens of thousands, and hundreds of thousands, it should essentially be a non-issue because there is plenty the designer can do in terms of cabinet shape to address it. Companies at the high end that are doing an extremely good job of addressing it are Vivid Audio, Rockport Technologies, and Revel. Even at the lower end, Definitive Technology has done a very good job in their new StudioMonitor 55, which sells for just $598/pair. We'll have a review of that speaker on SoundStageHiFi.com on July 15. There are others, of course, but I wanted to point out a few to illustrate that it is being taken seriously by some.
Doug Schneider
SoundStage! Network
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it's easy to deal with if you have anything resembling a cabinet budget, and a well documented and readily audible issue. Roundovers and felt aren't the only ways to deal with it but it is something that should not be ignored- and isn't, by any competent designer.
Bass is supposed to sound big. 6.5" is not a woofer size.
There are many speakers that don't round edges, or use a dampening material on the baffle. yet the continually get glowing reviews. One that comes to mind is Harbeth. They use old school rectangular enclosures with 90 degree edges. I would guess most of the companies have sophisticated testing and measurement equipment and can detect audible abnormalities. So three scenarios come to mind. One, they choose to ignore the problem. Two, they deal with it by signal alteration. Three, they attempt to deal with it with driver design. Just guesses.
And fourth, maybe it's not an issue worthy of the extra expense.
It's definitely an issue and any competent speaker design knows/addresses it. Now, granted, expense might factor in, but when we're talking about speakers priced in the thousands of dollars, it can easily be taken care of.
Rounding a corner more or less is at the tip of the iceberg these days for addressing diffraction -- you can do far, far more. Revel does an excellent job on the Ultima2 series. Vivid is another, and their paper here addresses the issue nicely:
http://www.vividaudio.com/technologies/technologies/acoustically-designed-cabinets.html
These days, if a company hasn't addressed diffraction well, they're shortchanging to consumer by doing shoddy work. It's as simple as that really. The post before mentions Harbeth. We've measured one of their speakers. Perhaps they could do more to address it, but they're doing a fine job as it is:
http://www.soundstagenetwork.com/measurements/speakers/harbeth_30_domestic/
Doug Schneider
SoundStage! Network
Seem to recall at least some of their sharp, rectangular boxes go for a VERY pretty penny, and are fairly well received by some...
Hello,
Ummmm, well, I've never considered Audio Note to be on the cutting edge of speaker design. That doesn't mean someone can't like them though -- to each their own.
But I think that's there's something not be well understood here -- what diffraction is. What's more important is that I think you'll be hard-pressed to find any credible speaker designer anywhere who tells you: 1) diffraction is a good thing, or 2) that's it's not an important consideration in good speaker design. Every good designer works to eliminate diffraction or works to overcome diffraction problems that a certain cabinet design might introduce. As I said before, if they don't, they're probably not doing their job as well as they should.
Doug Schneider
SoundStage! Network
Though I'd say - cutting edge or bleeding edge is sometimes silly. I'd never thumb my nose at research and design. Quite the contrary - I believe it is essential.
Will say that some engineers/designers/makers will put blinders on and push the limits of what is physically possible above and beyond what actually sounds good.
Some others will just stick to what was the rage at a particular timeframe & update the ideas with better materials.
Seems like this makes speaker design still partly an "art" and partly a "science." What is right for any given person certainly depends on their biases.
A hint to my particular biases? My GOODNESS do I love the immediacy and dynamics of a horn loaded system, but I laugh my backside off when they describe such things as "low distortion!" If it wasn't distorted, it wouldn't have that annoying HONK or SHOUT, and every part of the delicate bits would come through just like the best of the electrostats...
Hi,Looks like we're in agreement here, but I'll add a few things.
It's part "art," but it's not shooting-in-the-dark art like some people think. What's important to understand is that speaker design is a balanced of compromises -- there's no perfect speaker and there are always tradeoffs. It's how a designer balances these tradeoffs that matters.
I won't get into the details of those things here, but I will say that because of this thread it's important to know that diffraction isn't a tradeoff. In other words, one doesn't live with diffraction or not. If there's a reason to live with diffraction, then it's usually due to visual design being put ahead of performance (acoustical design), and then the designer has to deal with that. I've seen that quite a bit, and even talked candidly with designers who admit that happens from time to time. But no designer would put in elements that introduce diffraction because they're trying to achieve something else performance-wise. Now, they might not optimize the speaker like they could (because they don't have the manufacturing wherewithal, or they don't know). But when it comes to a TRUE cost-no-object, high-performance speaker, there is no excuse for diffraction-producing elements to be there.
Doug Schneider
The SoundStage! Network
Edits: 07/05/12
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