[rockadanny]

I think I was having a bad hormone morning. I am not growing old gracefully. My appologies all around. Moderator - feel free to delete my post.

[jimdgoulding]

Danny, you behave.  Is that meant for Wind?  You said what you're feeling and a few others, it would seem.  What I make is not gonna be universally successful.  Can't be.  There are too many variables at play.  In most cases on applicable speaks, it's very effective, but I can't always tell in advance and neither can a customer.  That's why I offer with a guarantee.  If you were to hear Wind's speaks, you might agree with him.  If he were to hear your speaks, he might agree with you.  Me?  I'd most likely agree with me.  Cheers.

[Wind Chaser]

I have a hard time imagining that the removal of diffraction will some how "muffle" the sound.  Clearly folks who make that claim are hearing something different with the Woolies in, but it's just not to their liking.  For them, diffraction is a good thing.  We've all questioned the taste of other people before...

The only way I can see the Woolies muffling the sound is if they are in too close proximity of the drive unit, or even worse, covering it.

[yammy1688]

Sounds the same to me.  Don't think I'm losing any detail either, but I certainly noted some sibilance in the highs without them.  I think depending on your system, this could translate into more detail.

My speakers are the MXe.  Pretty much exactly the same as yours except it's got a better paint job. 

Yammy, besides looking better, do the narrower woolies sound better on your TSMs?  (Are those the TSM-MMX?)

I have the TSM-MMe and the woolies I got look like your original tall version. Mine also extend past the curved edge of the baffle.

Can you post more on your impressions of the sound. You seem to like them. Did you think there was a loss of high end detail?

thanks

[jhm731]

Jim-

Got my diffractionbegones.

Mahalo,

Dan

[drphoto]

I'm starting to like the sound w/ the woolies in place more all the time. I think I was first infatuated by all the perceived high end detail  I was getting without them, but I'm coming to believe it sounds more natural and less 'hi-fi' with them in place.

I guess it's akin to a new girlfriend who hangs around all the time. Fun at first, and then starts to become annoying.

Can these be trimmed w/ a very sharp knife....say a scalpel?

[jimdgoulding]

I'm starting to like the sound w/ the woolies in place more all the time. I think I was first infatuated by all the perceived high end detail  I was getting without them, but I'm coming to believe it sounds more natural and less 'hi-fi' with them in place.

I guess it's akin to a new girlfriend who hangs around all the time. Fun at first, and then starts to become annoying.

Can these be trimmed w/ a very sharp knife....say a scalpel?

You, drphoto, can hear between and around instruments better now cause yer not getting reradiation or diffraction off your baffles.  That's the physical reason.  Information germaine to an instrument and how it is being played is made more available and able to be perceived.  Artifice, tho it can be made musical, what I submit you are missing (I don't know of a kinder way to put that), is often the result of designers having to work around physics.  Stay tuned.  You may begin to hear more detail, still.  What kind of cutting are you wanting to do?  Please let me know here or in a PM.  I'd like to help, think I can.

[jimdgoulding]

Ozymandias wrote:

"Unfortunately, the magic box room equalization fails to adequately address non-minimul phase conditions, which CANNOT be equalized.

The MOST that can be equalized are fundamental room modes where the peaks can be damped - not completely, but to a degree.  The remaining specular reflections cannot be addressed at all - except to slightly move polar lobing and nulls about by the superposition of small changes in phase. Has anyone bothered to notice why the literal racks of EQ that used to be the norm in sound reinforcement (SR) units have all but disappeared, with EQ reserved strictly for the direct inputs?  Ever wonder why?  But then, this debate was lively back in the late 80's - only to still be news to the audiophiles as we speak.  I am always amazed that the 'audiophile' world is so far behind pro-AV in understanding basic acoustical physics.

But the magic boxes and equalization CAN homogenize the anomalies so that you do not notice a pronounced spectral reflection by rendering the difference between one position and another less noticable - in other words, you don't have a sweet spot and an abysmal spot - you have a larger more uniformly mediocre spot. For some reason I do not see that as progress. Rather it is raising mediocrity to an art form."

[Hi.  I have imported this from another place to bump the goings on here and because it is cute (I think) and Oz is a unique personality.  This particular audience doesn't have the audio IQ of you guys.  I'm a little coy in the opening of my reply cause I suspected Oz's patience might be wearing thin with my comments.  The topic, his topic, was more about room effects tho he acknowledged the nature of diffraction, for sure.  There hasn't been much acceptance on either score.  Cheers]

jimdgoulding wrote:

"There you go, Rude god, Julian. A few speaker designers do put a null in the area (output) where linearity is made amuck by, dare I say it, OK I won't, things. Reflection in whatever form and the offense caused to time and phase correctness can be dealt with by an end user for not much money. Good guidance, better than good, is available right here. Oz may be a little intimidating to read but when asked questions, and I would include myself on a smaller scale, I don't think he would be anything but helpful. Most everybody has a little or a lot to gain.

Look at it this way, you have a music library that you love. You have equipment you've spent a lot of money on. The realization of all that at the end of the line is in sound waveforms. What was once acoustical (the event no matter what it is) becomes electrical and then acoustical again once it departs your loudspeakers. Your room, no matter the size, and your speaker enclosure itself if it is a box, is being a part of your reproduction. The effects of your speakers and room, or should that be affects (?), are not a part of the recorded event but it is being made a part of the happening of a recorded event. Just moving your speakers around can make them more or less complimentary to your end game, you've experienced that.

Now, you do want the (recorded) event recreated in your room, don't you? Don't you think the minute information about how an instrument is being played or its harmonics or spatial correctness will allow you to be closer to that? And happier? Or, maybe you're just in this for show. Regardless, you've spent an awfully lot of cheese, haven't you, so why not give your senses the full benefit of what's in your recordings and your system is working in earnest to deliver. Seems only fair, dunnit?

I keep waiting for somebody to ask more questions. To undertake this as a next step. Speaking from experience, I would say that you should begin doing this before you put another piece of equipment in your mechanical chain. Even an accessory. Everything upstream of your speakers and room, what you have now or add later, will thank you. And you'll start posting and telling friends because you'll be excited. And why not, you will have done something that you hadn't imagined would be so extraordinary, or for so little money."

[jimdgoulding]

I got this from a customer the other day and it's right on hip:

http://www.classicspeakerpages.net/IP.Board/index.php?act=attach&type=post&id=4065

Made me think of Jim N.  The 1-5db reduction that the author is talking about isn't across the board, it's a reduction of peakiness in the lower bandpass of the tweeter and beyond caused by diffraction and what is sometimes described by customers as a loss of something.  It's a loss of variance is what it is and a return to linearity.  Like, tonal accuracy, practically speaking.  It's also why listeners report more detail is apparant in their midrange.  BTW, I have replaced two Madisound numbers that I know of.   

Herbie Hancock's DVD about the making of "Possibilities" is on cable this morning.  This thing damn near makes me sob in places I so love art and the making of it.  Count me as a dude who highly recommends it.

Ya'll have a great day.  The weather is beautiful where I'm at this morning.  Wish you some of it.   

[konut]

I contacted Jim the end of Oct.'08 to inquire if anyone with horn tweeters had used his product to try and dampen the HOM, high order modes, inherent in all horns. Dr. Earl Geddes had discovered these aberrations as a form of diffraction in his investigation and development of the oblate spheroid horns he uses in is designs. While the oblate spheroid minimizes these modes, it does not eliminate them completely, and Dr. Geddes utilizes an open cell, 30 ppi or pores per inch, foam plug in his horn to address them further. This method requires adjustment in the crossover to correct frequency shaping that the foam makes to the response of the driver. The Timepiece Minis I own use a proprietary variation of an oblate spheroid. As I did not have the option of cross over adjustment, I thought that I could take a stab at attenuating the HOMs using the wool felt that Jim uses to address the diffraction on flat baffles. Jim informed me that no one had used his product in this way before. After numerous emails discussing the various ways the felt could be used, we came up with a scheme of strips radiating out from the center of the horn, toward the edge of the baffle. Jim sent me 8 scrap strips to mount. It soon became clear that these strips were too thick and did not provide enough coverage to significantly affect the sound. I proceeded to split them in half, a tedious process indeed. But no more tedious than the process of attaching them to the baffles using the hook and pad Velcro stick-um thingies that are used in the diffraction be gone product. The effect was subtle at best. I decided to leave them in place as I knew in the coming months I would be making numerous changes, hopefully improvements, to my system. Better to let them become a part of the "system fabric" as it might be easier to judge their effect more accurately by their elimination once all the other beneficial changes to my system had occurred.
      There was the Bryston BDA-1 comparison with the Van Alstine Insight DAC, and the addition of the AV123 X-Amps. I got new speaker stands, with granite tops. I tried sad balls, inert decoupling spheres, under the granite. These did not work. Brass cones and discs were much more preferable.
     At this point I removed the wool strips. At first, there was not much difference, with just a little more treble energy present. Jazz and rock were little changed with the exception of the cymbals increasing in loudness seeming to move them closer to the front of the sound stage. I put on some jazz with a trumpet with mute as I've heard that the mute causes some really high overtones to be created. Apparently the overtones created were not on the recordings I used as I could not detect much change. Then I put on one of my favorite  classical cuts, Tchaikovsky's Violin Concerto in D played by Leila Josefowicz and the Academy of St Martin in the Fields. As soon as the upper registers of the violin were presented, an edgy, grating overtone became evident. A sound I had mistakenly associated with digital hash would increase with volume and higher frequency. This was just as it was found by Dr. Geddes, that HOMs are more evident at higher SPLs, at increasing frequency. The overtones of the violin had excited the diffraction. As soon as I replaced the strips, the edge and hash diminished, replaced by the smooth, detailed presentation I had grown accustomed to after 3 months. To be sure, the strips are fugly, resembling giant spiders attacking my tweeters. As I could care less, and don't have anyone else around here to mollify, they're not going anywhere. They only affect the sound at higher SPLs at higher frequencies, but the effect is much more preferable with them, than without them. I suspect a more effective and aesthetically pleasing implementation could be devised by form fitting the wool completely to the horn. It would still obscure the wood finish. It is not clear if the foam that Dr. Geddes uses has more of a diffusion or diffraction effect. Perhaps there is a better material than the wool felt that would be both better looking and more effective in the diffraction/diffusion effect.
     To review, and be completely clear, the wool strips, as I've used them, attenuate a certain hash present in higher frequencies but only on certain instruments and only at SPLs over 80 db.
     I'd like to thank Jim for allowing me to experiment with his product to investigate its effect with my speakers.   


I'm cross posting this to the SP Tech circle, as maybe SP Tech owners might find this info useful. 

[jimdgoulding]

The SPL's at high frequency are NOT SPL's at high frequency.  They are a peak in the lower bandpass of the tweeter.  This is a diffraction effect.  And what is a peak followed by in listening terms?  A shadow is what.  In the absolute sense of it, it is inaccurate and amusical where it exists.  Come on Duke and Dr. Geddes, help me out here.  This is not a criticism.  It just something and it can be dealt with as the Duke, the doc, Danny R. and Bob Smith are doing to the extent it can be done without free mounting drivers and that's another can a worms.  And yours truly, on conventional box speakers with surface mounted tweets where diffraction is most prevalent and invasive. 

[konut]

What frequency(ies) are you refering to?

[jimdgoulding]

You know, Konut, you have just given me a wake up call.  And that's good as I need remember that Timepiece Mini's crossover at 800Hz (!), rather out of the ordinary.  My statement was based ON the ordinary, pardon me, and in that case between 500 and 10kHz on a more typical two way.  The widest variance would be in the neighborhood of the crossover.  So, in your case, I can't say that my statement applies as stated. 

A simple graph provided by Danny R. on his AV1's can be seen here: 

http://www.audiocircle.com/index.php?topic=45876.20

Danny also included (to me) a 40 degree off axis study that showed a downward slope above the crossover of up to -4db.  Some guys take theoretical issue with this but all it means to me is that the energy hitting side walls would be less strong at the listening position.  And I lifted the following made by Duke on AC 5/17/08:

***Diffraction can degrade not only imaging but also clarity***

***The most important region for diffraction control is around 4 kHz, as this is where the ear is most sensitive.* **
 
***diffraction is more audible at high sound pressure levels than at low levels.***

Windchaser would tell us that diffraction effects are plenty audible at low listening levels.  80db in his case.  There is ALSO the issue of out of time and phase info arrival (diffracted) what the Dukester refers to on the first line.

Thanks for pulling my coat.

 

[Wind Chaser]

***Diffraction can degrade not only imaging but also clarity***

Most definitely. Anyone who believes in room treatment should be able to grasp this.

***The most important region for diffraction control is around 4 kHz, as this is where the ear is most sensitive.* **

But don't under estimate the difference controlling diffraction makes at lower frequencies down to 2K.  If your speakers are properly set up the difference is anything but subtle.  In the same way a sub compliments everything above it's range, so does restricting diffraction at higher frequencies has a very complimentary effect on rest of the audible range..

***diffraction is more audible at high sound pressure levels than at low levels.***

Windchaser would tell us that diffraction effects are plenty audible at low listening levels.  80db in his case. 

You know it's funny, since I've integrated the defractionbegone pads into my system, my listening habits have changed.  Not always, but quite often, I'm listening at louder SPL's.  The pads are simple  but the effect is profound.  Easily one of the most seductive and effective tweaks I've seen in at any price.  That includes expensive cables and power cords, connectors, tube dampers, room treatments, isolation platforms, spikes, etc.

[batmanslc2]

I will echo windchaser here, these pads are very simple low cost and effective! I am glad to have found them here on audiocircle.  Just go order some.
I've said it before, but check out millennium cd mat as well  http://www.dagogo.com/Millennium-M-CD-Mat-2009.html
it brought the sound quality from my oppo 983 up  a notch or two, I heard smoother, more rounded sound and more spaciousness.
I use it on DVD's as well
Herbies black hole cd mat was also an improvment, but not as good or convenient as the millennium.

enjoy

[jimdgoulding]

Jim-

Got my diffractionbegones.

Mahalo,

Dan

Just a bump so my small contribution (and custom fitted) to higher fidelity to the source doesn't fade too far out of sight.  I'm always willing to answer questions.  Conventional box speaker owners with surface mounted tweeters . . you have diffraction effects and your stage will open up and instruments liven up and be more there without it.  Tonality improves without it.  You'll be keeping the first arrival from being messed with, transient response pure and clean, how your speakers can sound at their best.  Heck, man, your SYSTEM is better than you think!  Proof of that is contained in sound waveforms at the end of the day.  Best we preserve them.  Guaranteed to please, literally.

[jimdgoulding]

Hi Konut.  All, were I to make a bonafide product for any speaker using a waveguide, I would do so as Konut mentioned from our discussions (above), as a liner 1/8" in thickness.  It would begin a little further out in the guide than Konut has placed his strips and terminate just as the roundaway begins.  It would look integrated.  Well, more integrated, at least.  This is the first experiment with a speaker using a guide that anyone has shared with me.  I have a neighbor with Timepiece 3.0's and Mini's.  I would like to hear for myself what Konut is hearing and I may get around to fitting for these.

It is box speakers with surface mounted tweets that will benefit the most.  Virtually all have diffraction effects.  Those with very wide cabinets can cheat the hangman to a degree because edge diffraction will arrive later in time and be perceptively more benign.  Those with rounded or canted back corners will also be less vulnerable if the round away is two inches or better.  Waveforms lower in frequency are longer in length and will escape interaction with our front surfaces and edges.  Spica treated the entire front surface tho I expect that may have been for visual reasons.  Covering only the space adjacent to tweets is rather more conspicuous but is all that's really needed.  The exception is sometimes 3 way speakers depending on how much of the shorter waveforms are produced by the mid driver.  I make fascias rather than rings to insure that the entire culpable surface is damped and waveforms don't travel to the edges.  They see the organic wool and are absorbed.

It is waveforms above the midband that give us information about the rendering and separation of instruments.  The arrival of diffracted waveforms confuses this because it is late arriving and out of time and phase with the first event arrival.  There's more . . In the lower bandpass of our tweeters, at and around the crossover, edge diffraction may cause a bump and ripples to our frequency response.  This has been measured in before and after studies using different speakers on every study sent to me.  When this is made more linear, the transition to our midrange is smoother and information made more intelligible and sincere.  When timing and transient info is undisturbed, there is more 3D life to the reproduction of our stage.  This is all audible and pleasure enhancing.  I can testify to that (as have others) and is my inspiration for making these.  I sure ain't gettin rich.

Speaker designer John Dunlavy attributed what has come to be known as listener fatigue to time and phase malady.  So, if you can get around the looks, there is a lot to be gained.  I tell people . . "They're sure to be a conversation piece".  And, they work beautifully.  You might think so, too.

Sp Tech's and speakers using a guide don't suffer in the same way regards diffraction effects or to the degree of conventional speakers.

Thanks, Konut.

[jimdgoulding]

Hi Jim,
      I'm still using those giant spiders.   I would be VERY interested in something that would fit the horn better. Let me know if and when this variation becomes available. Thanks again,  Ted  (transposed from the SP Technology Circle).

You betcha, Ted (Konut).  I'll be happy to.
 

[keenween]

I had my pads off the past few days so that I could trim them to fit underneath my speaker grills. I had forgotten what a difference they make! I'm happy to have them on again.

[jimdgoulding]

Thank you, Keenween, for saying.  I've begun to offer in black and charcoal.  Actually, I can offer in as many colors as there is commercial dye available to match your speakers.  I would require only that a person pay for the dye and the gas to go get it, say, six bucks (?).  I live in the country.  And I can size them to fit inside a speaker grill.