Diffraction and its effects . .

jimdgoulding

jimdgoulding

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is something I've made a study of and custom make an affordable after market product for its removal. For those of you who don't know, diffraction is the reflection of waveforms shorter in length than the width of your speaker cabinets or those produced by your tweeters. This is not something owners of Gallo speakers, for example, or any baffleless speaker to include planars, need be concerned with. It is for the owners of box speakers with right or near right angles. Diffraction in action:

http://www.silcom.com/~aludwig/images/diffdem.gif

Those green and red circles in the illustration by Al Ludwig are not a part of any recording that you own and are additive in your frequency and time domains. They are redundant and late arriving, out of time and phase. Some speaker manufacturers, not very many, compensate for a rise in the frequency domain caused by diffracted waveforms summing in by reducing the tweeters output just above of the crossover, but the time and phase anomaly persists to the detriment of the clarity and dimensionality inherent in good recordings.

I use organic wool and individually fit to the dimensions of most any speaker baffle and offer with a 30 day trial period. You should give it a try. You just might find that it is the best value audio investment you've ever made.

Some user and reviewer comments can be seen on the back page at my website: www.diffractionbegone.com.

Thank you.
 
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Diffraction

Could this explain why I like my Tannoys so much?Not much chance of this problem occuring with the H.F.unit set back into the L.F. cone which is set back flush with the front mounting board.
 
The reason you like your Tannoys is probably not due to diffraction. Dual-concentric designs like the Tannoy have more diffraction than the majority of speakers, mostly from the throat termination between tweeter and woofer cone and from the cone to cabinet which has a relatively sharp termination. This is the basis of progression for the Genelec 8260A concentric driver.
genelec-8260a-mdc.jpg
 
Hi, Tenson. Brilliant, brilliant design! Very handsome, also. I believe those are active speakers like my Meridians. Would that be correct? Sure wouldn't mind having a pair of those onhand. Short of that, use of the pads I make will give very much of the same benefit regards diffracted waveforms and their ill effects. They are absorbed and dissipated.
 
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A review, if I may be permitted to post it, by Filterlab on The Art of Sound Forum:

--------------------------------------------------------------------------------

Like most audiophile chaps, I'm definitely up for a tweak which is preferably all of the following things:

1. Effective
2. Easy to install (i.e. doesn't require a degree in electronic engineering!)
3. Cheap.

So as if by chance the perfect tweak offer dropped into my lap seemingly out of nowhere! After extensive listening and loving of my Revel M22s and having tried them on different surfaces and with different cables etc etc I was very VERY pleased with their performance, surely nothing could make them even better?

Well yes actually, and for a darn sight less than they cost to buy. In fact an amazing tweak was had for just 1.4% of the price of the speakers. YES! For £28 including taxes and shipping, my esteemed acquaintance Jim from diffractionbegone created a pair of baffle covers to perfectly fit my speakers.

So the science is not really up my street, but what I can hear are the effects of a scientific principal working in my favour, and boy can I hear a difference with these things! Have a look and see how they fit, and I'll tell you how they effect (read as 'improve') the sound.



(Sorry, couldn't bring the photos forward tho an example is in my avatar)



Now you may balk a little at the looks, but in the flesh they look superb and if I'm honest the looks have really grown on me. However, it's not about the looks I hear you say. So the sound...

Well my friends, the difference these things have made is nothing short of staggering. I was expecting it to effect the treble, but in actual fact it's quite the opposite.

The first thing that really struck me was the midrange clarity - think 'crack of the snare', 'clap of the hand' and 'strum of the guitar' and you're on exactly the right lines. The focus in this audible region has to heard to be believed, but that's not all - oh no! The other amazing element is in the bass lines, particularly bass guitar, which takes on a start/stop nature that is as tight as the deft handwork as any talented guitarist. Again I'm going to use the superlative 'focus', clarity in this region is so improved, amazingly in fact.

So is that it? Nope, there's two other areas which are even more impressive, namely imaging and vocals. Imaging on my Revels was always a little bit of a sticking point after owning some Martin Logan electrostats, but these baffle covers have augmented the imaging to near-electrostat levels, and that's saying something. I guess this is why vocals sound sooo good, they just stand so clear from the mix with such audibility and yet never become overblown.

If you have thirty quid that you fancy putting towards a positive tweak in your system, you'll NEVER go wrong with these.
 
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