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Is diffraction tolerable?

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As stated by Tenson, speaker cabinet roundovers can minimize diffractions effects, agreed. They just need to be pretty generous, like Theil speakers, for example.
 
Well, then, here we are. It seems that the existence of diffraction has been pretty well established. I'm not dreaming then, am I. Something that you, dear reader, may not know is that it's most prevalent and offensive on smaller speakers (not excluding floorstanders). If a speaker has a wide box, diffracted waveforms are not arriving so quickly making them less invasive to the first arrival of information. Off setting tweeters is another method of spreading out their arrival over time, quite common in British speaks it seems to me. On speakers with centered tweeters and more narrow cabinets, it is a bad thing. Rather than trying to describe its offence, let me try and tell you what is to be experienced and gained instead.

The leading edge of waveforms arriving free of a second wave of the same information is entirely important to the virtual creation of instruments before you. The continuum of space in a recording is made more linear and therefore intelligible. Transient information is preserved. Things arrive more evenly sequential in time. The mouth sounds of a singer, the tap of drum stick on whatever, the finger action on guitar strings, the sound of air leaving a trumpet. The entire sound picture becomes clearer. You can see between and around instruments better. Their shape and how they radiant dimensionally. The gestalt of an event is made more real and present. And YOU are made more involved because the artificiality caused by diffracted waveforms and the information they carry is shown the ****ing door.

There is a benefit to tone as well timbre. In the lower bandpass of the tweeter, diffraction causes an unevenness in the frequency response. This is an abberation to the absolute tonality of any instrument falling into this range. And virtually all do at some point. This is made more linear, flatter, when diffraction is removed.

This past Saturday, a guest said that my system sounded like a whole different system depending on what we were listining to. That's the kind of fidelity to the source that is to be gained by removing diffraction because that is all I've done in the past two years. I have no doubt that this could be made even better by damping the first reflection points along the adjacent walls but in my room (probably not much larger if at all than rooms in an average British household), I am in no hurry to do this. I am spellbound most everytime I sit and listen.

Are my speakers typical? No, they are actives and their drivers time aligned in the crossover. But, most of my customers listen with more conventional speakers and are sold on the results. I didn't know if that would be the case when I first starting making what I make but it has proven to be very beneficial to one degree or another to 95% of my customers. On the chance that it isn't, I offer with a guarantee.

Of course, an inexperienced person may think that any ole wool will do. This would be incorrect. The wool should come from a sheep, not a petroleum related or synthetic substitute. The absorption properties are important.

If you were sitting where I am sitting, you might be as dumbfounded as I am as to why there isn't more people anxious to try what I make* especially at the price of it. For some reason, listeners in the states and in Australia are far more willing. Is it that old ****ing yank, thing? Well, I'm a liberated and compassionate human and don't fall into any stereotype.

To Andrew, who posted above that he might try some carpet wool over the weekend . . Andrew, leave your carpet wool be and permit me to send you a set of what I make fitted for your Dyn's at no charge. All I ask is that you listen well and post your impressions. Would that be ok?

Be well. And don't shoot the messenger. Thank you.

*I understand the looks thing, but I guarantee that you'll hardly give it a second thought after a few nights of listening.
 
This is worthy of comparison with HiFiPlug editorial material
due to-

sheer length and thickness
solipsistic fragilistic
elevation of the marginal to the fantastical
relevent to another (past) economic era
 
Dave- Your point was understood and I thank you, again. I've stuck my chin out in this manner before, I'm no cherry. Some guys will take an interest in WHAT I'm presenting and the potential for their world. It's an honest and highly effective product for what it does. That's been proven. And some guys just take a swing at me. This guy who posted ahead of you is just diverting attention to himself and there is nothing constructive in what he wrote. I'm a doer. And aren't you? The places I've been, someone will give it a go and post their impressions. That's what I'm hoping for. That's all its taken so far.

I'm thinking of advertising in TAS but I'll never abandon audio chat rooms. I'm a subscriber to the good I believe they do. Cheers.
 
jim,

Even if done in a good intention, when a trade member pushes his/her product, everyone's b.s. meter goes up a little.

I think sharing good insights and experiences with trade folks is vital to keep the interest going on any audio fora.

The key, to be heard, however, is in delivery. Many folks don't appreciate heavy handed approach especially the PFM had a history of a few trade members who got out of line. ( clear AUP breach )

I've pruned a few noises earlier to prevent the thread from derailing.

If you are intend to do online guerrilla marketing, tho, you'd better grow some thick skin.
It's a tough crowd.
 
This is good on topic communication, I think (an exchange on another forum):

Originally Posted by jandl100
Review the 3rd .....

"I've been playing some more with JimG's anti-diffraction baffles. My latest hodgepodge of available parts has the tweeters on my Bowers Active Ones surrounded by the rectangular baffle originally intended to fit around a ribbon tweeter, and a selection of offcuts butchered from baffles intended for a small midrange unit to go around the mid cones (sadly too small for the 6 inch mids on my Actives).

Effective as the tweeter baffle is, I suspect the biggest improvement is from surrounding the midrange cones with anti-diffraction baffle segments.

See pic below for current arrangement.



Hmmmm ..... I'm really not sure I can live without these baffles now. Remove them and the sound seems diffuse, smeared and badly focussed. Damn, but these things work well!

_____

Jim also sent me a set of baffles specifically tailored for the Actives' tweeters, but *shock*horror* they are light-ish grey, rather than the rather fetching black of my original baffles (purchased for my abortive attempt at owning ProAc Future Point Five speakers). Just a no-go aesthetically, for me - I listen with the speaker grilles off and the light grey slabs on the black speaker baffles is just too eye-catching and off-putting. They do sound marginally better than the 'ribbon baffles' though."

As the frequency goes down, waveforms become physically longer. They wrap around our enclosures and are reflected later in time by room surfaces and boundaries. The frequencies most responsible for the rendering of instruments are propagated by our tweeters. These waveforms are very short and carry the first arrival of midrange info along with all things high frequency. Critical waveforms they are and it's these that are being diffracted by our baffles and cabinet edges. They would be arriving out of time and phase with what your tweeters just sent to you. They muck up your presentation spatially and dimensionally. Using my pads will allow you to see/hear between and around instruments more clearly and deeper into your stage. Your soundscape and the instruments that occupy it are rendered more palpable and recognizably real.

Here is an animated illustration of what diffraction looks like in action (this was not made by me):

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

In addition to preserving correct time and phase the removal of diffraction flattens out a deviation or loss of linearity in the frequency domain that is germaine to it at and beyond the crossover. In this regard, a few speaker designers put in a -1db or so dip in their output in this area so this is made less audible. Good for them as that is proactive but most don't do this and you don't see it in published frequency response studies (any) but you ARE hearing it. Those studies are made in controlled settings and at a standard distance from the microphone that has little in common with real world listening environments. Customers tell me that more mid range info emerges using my pads and it makes sense . . for every peak there is a shadow in listening terms. Proper tonality is preserved.

The mechanics of music reproduction should be inaudible and speakers as sources invisable. That's what using my small thing does.

I offer with a 30 day buy back guarantee so you can audition for yourself and I custom fit to a particular speaker. Better listening thru simple science. Your system is better than you think!

Oh, and I can dye them black for a nominal fee (the price of quality dye and the gas to go get it). Cheers

Then another fellow posted this:

"It's an unfortunate truth that many commercial speakers, even expensive ones, have quite serious design flaws. This can be due to simply errors being overlooked and also being purposely ignored in order to have a product that's visually appealing.

While I have never used these diffraction baffles I can say that I had a lot of success with using felt to surround the drivers of my DIY speakers. I'm positive that it played a huge part in the pinpoint imaging that they had.

I love this kind of stuff as it's a lot cheaper than things like Mains leads and fancy isolation feet but has a far more noticable improvement. Quite frankly I think that anyone is nuts if they spend a fortune on other ancillaries before using things like this as their effect is far greater.

Of course I have to put in the get out clause of this is all IMO but if you're going to spend a few hundred quid on an interconnect or something try spending a fraction of that on things like this as you can obviously afford it!"
__________________

I'll get on hoping on and try and chill out.
 
jimdgoulding said:
To Andrew, who posted above that he might try some carpet wool over the weekend . . Andrew, leave your carpet wool be and permit me to send you a set of what I make fitted for your Dyn's at no charge. All I ask is that you listen well and post your impressions. Would that be ok?.
Click to expand...
Thanks for the offer, but I'll buy a set *if* I think it worth pursuing.
 
It would seem that those of you for whom this mod is intended, those of you with speakers like Andrew, conventional box speakers with surface mounted tweets, ought to do a little research on the subject of diffraction and its effects. There is quite a lot to be gained in their performance for very little expense. Not merely your speakers, but the purity to information your system is working to deliver to you. All that is contained in the end in sound waveforms.
 
That's an interesting set of pictures in that thread Jim, He's really wanting to extract all he can from his system. I know a lot on PFM also ascribe room treatments and there are lot of options, but equally lots here who don't 'do' room treatment.

Not to make any judgements at all, but I don't 'do' room treatment myself as I am a family man & we live in our living room. I also feel that a systems performance should not depend on room treatment & correction to sparkle, though I understand we are talking about optimising performance here, not merely making poor kit sound better.

I guess I am lucky to have a room that's OK acoustically (no better than that) and a wife who initially lets me arrange the room to accommodate & prioritize music listening, so I should count my blessings. I pick my kit to match my room.

So for all the other listeners who don't partake at the altar of acoustic panels & traps, can I reassure you through my own experience that Jim's surrounds do not need to incorporated into a serious acoustic treatment programme - they stand on their own merits as individual tweaks that give genuine results. They are unobtrusive & relatively affordable, Jim is a gentlemen to deal with and there is a money back trial period.

The surrounds help to define the upper midrange most of all, allowing musical detail to clearly project without fatiguing me, so I can more clearly hear the attack of guitar stings, and the variations between each chord or note. Because this detail is 'released' better into the room, tone & timbre sound richer too, so everything is more relaxed, the imaging also seems to benefit.

I guess I'm trying to say these surround improve 'sound' - tone & timbre - as well as presenting individual musicians intentions more clearly. The effects are fairly subtle, but noticeable, on my speakers a definite improvement.

On WigWam there used to be a set supplied by Jim solely for trials - each listener would post the set on to the next person who wanted to try them. Perhaps it would be worth doing the same here? If someone wants to see what they do in their own environment, ask Jim to mail a set; they can then be forwarded to the next curios fishie.
 
Thank you, Alan, for your words and echoing the feedback from others I’ve gotten.

More important in my opinion than room treatment is synergistic speaker placement within our rooms. I listen in a small/medium size room and my triangle is 3, 4, and 5 feet from the walls of my room without going into more detail but I have the luxury of having a dedicated rectangular room with parallel opposing walls. The customer in the picture has his speaks nearer his room boundaries so room reflection is going to be more of a problem for him. He is trying to get a warmer balance and a wider stage. I would advise him to pull his speaks further out from the adjacent walls and place his bum (er, ears) at the apex of an isosceles triangle not much longer than equilateral. His stage would actually gain breadth and realism were he to do this. From there, I would suggest that he remove his corner and wall traps and listen. It might lighten up his balance- his size speakers are small to begin with- we would have to see. He could always reinstate one of both sets of his traps if he should care to.

The use of his tweeter surrounds in addition to preserving the first arrival of information is actually reducing the strength of energy being reflected by his walls at least above his crossover. And were he to follow my advice waveforms from both drivers would be arriving later, also. It is the transmission of shorter waveforms propagated by our tweeters in multiple driver designs that is responsible for the intelligibility of what is being played and the setting. His tweeter surrounds are doing more work that he realizes.

I have already offered to do what you suggested for a pink fish’er that declined to take me up on it. I renew the offer to anyone with the understanding that once you’ve auditioned, let members know you will forward to anyone else who might care to do the same. The size would have to be generic, obviously. For those who care to purchase, I would provide a custom set.

Again, Alan, thank you.
 
The link to the photo mentioned in the text above is temporarily out of service (don't know more than that at this time). I encourage you to read Alan Brown's letter regardless. Thank you.

Link back in service and more.
 
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