All I see in those pictures are the panels, the review is also of the panels alone not in conduction with any bass section.
david
What does a "great room" mean?
- Thread starter jkeny
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All I see in those pictures are the panels, the review is also of the panels alone not in conduction with any bass section.
david
There's a sound wave and it will interact with the room. Don't get me wrong its a very interesting tech but you can't bypass fundamentals.
david
Hmmm, it is my understanding that traditional speakers which operate based on a cone pushing/pulling according to the signal at the voice coil mostly produce correlated signal. Any flexure of the cone is considered a resonance best avoided, no?
Ok, I hear your skepticism & as I say I haven't yet experienced one to give my opinion on whether the reality lives up to the theory but so far I like what I see in the theory & the published results
Yes, controlled directivity is one way to avoid the worst of the side wall reflections (not the back wall) but that implies a narrow sweet spot, no?
Yet we have the benders exploiting resonance. My point is that due to flexure a cone or dome will have uncorrelated output as well. We've gone through pulps, plastics, metals, ceramics, sandwiches and layers together, even diamond deposition. Stiff as some of these are, arguably the stiffest still ring which is deformation as well. Whats more, things like choosing crossover points or actual crossover driver correcttion being active or passive, like the benders can be manipulated to the extent where characters can be consistent between models in the same designer's line despite having drivers of differing materials. Most important of all is that purely pistonic behavior which benefits transient response is not always avoided. Paper is a good example, theortically the transverse properties that come with paper cone flexure without going into brake up adds to texture via broad projection. It also smooths out odd order harmonic resonances. No wonder they do particularly well reproducing electric guitars and a big reason aside from tubes that paper cones are usually what you would find in an electric guitar amp.
Lastly CD does not always nean a narrow or for that matter shallow sweet spot. That depends on the shape of the horn and the size of its mouth. Notice that tweeter horns are very short, upper midrange horns short but wide and bass horns wide and long. They will give you a soundstage that may go little behind the speaker plane but big wide soundstages in front of them are there. Goes back to the earlier discussion of ITD and ILD. The ILD characteristics still do give depth perception and the not as narrow as one would think dispersionstill gives great placement within that stage.
When people think of CD speakers taking out side reflections, I find the assumption is that they practically have none. Of course they do. The difference is that the first lateral reflection points are just simply farther into the room placing the reflection point further forward and firing behind than a conventional speaker in the same place where their first reflection would more like you hit you directly.
David, we seem to be going around in circles here? The bending wave panels seem to produce many waves of an uncorrelated nature rather than a single correlated wave as a traditional speaker does. Of course there will be reflections in both cases but they will be different - many smaller uncorrelated waves of lower amplitude will not present the same interference pattern as a single correlated, higher amplitude reflection. This just makes sense to me.
Where I have a problem with bending waves is where these many uncorrelated waves become correlated into a single point source - is it in the far field or is it a psychoacoustic effect? This I'm still unsure of- I suspect that the answer lies in Wave Field Analysis where a waveform can be synthesised anywhere in the room by an array or matrix of smaller speakers?
But again isn't it a matter of degree - traditional speakers MOSTLY output a single correlated soundwave, bending wave speakers, MOSTLY output many smaller amplitude uncorrelated soundwaves?
I thought electric guitar distortion was achieved by controlled overdriving in the electronics & the upper harmonics these produce, not as a result of distortion in the speakers?
OK, I stand corrected, thanks for that info. As far as I'm concerned it really is down to auditory perception - so whatever builds the best, natural sound work for me - the how of it's operation is immaterial but nonetheless, interesting
Looks like we got to get a pair and see! I'm curious about a full range transducer, lots of neat projects can be done with a good one!
david
As far as guitars go it's both John. You're already in the ballpark when you attributed the diffusive nature as not having a small focal point. If that point is a two way the point is generously the size of a walnut right between the midrange and the tweet. With something like a Gobel its the size of sheet of paper. From teh listening position that walnut is now the size of your pinky's finger tip and that A4 Paper sized piece of bending wave now the size of a reader's digest.
If you look into Wave Field Synthesis(WFS) you will see (you probably know this already) that an array of speakers spaced fairly sparsely, can recreate a waveform that behaves as if it originated from a single point source & this happens from any position in the room. It seems to me that bending waves are a subset of this behaviour? Whereas WFS is the result of analysis of the required waveform & algorithmic splitting & time delays of the signal to each speaker in the matrix/array, bending waves seem to achieve the same result without the analysis/algorithms
Hello Jack
That's not really true they have reflections in the same places the real difference is the db level due to the directivity of the horn. You have to remember that the traditional definition that defines a horns coverage pattern is the -6db contour line looking at the polar response of the speaker. The output doesn't just stop as you point out it just falls off so if you look at the polar's of a CD speaker there is output just greatly reduced in level. So you get reflections at significantly reduced levels.
Rob
Hello Jack
That's not really true they have reflections in the same places the real difference is the db level due to the directivity of the horn. You have to remember that the traditional definition that defines a horns coverage pattern is the -6db contour line looking at the polar response of the speaker. The output doesn't just stop as you point out it just falls off so if you look at the polar's of a CD speaker there is output just greatly reduced in level. So you get reflections at significantly reduced levels.
Rob
Nitpicker
You know we're saying the same thing differently. 
Just as I'm sure you get what I said. I thought your attempt to correlate Rubber meeting the road with Music bouncing off walls was poor at best but was unable to offer a sufficient response. So I let it go.
Of course no two Formula 1 or Top Fuel drag teams are identical doing the exact same as each has room to add their own twist, fine-tune, etc. That should go unsaid. Just answer me this. Are F1 teams (and Top Fuel teams) more alike with other F1 teams (and Top Fuel teams) and shooting at the same target or are they more different than alike? And how about the cars themselves, are they more alike in design and parts or different?
Yes, I do keep on using the noise floor term. You can see what a noise floor does visually with a blurred photograph and anything below that visual noise floor you're not seeing, but only that which remains above the visual noise floor.
Same with an audio noise floor. Just as with the visual noise floor, ultimately it and it alone determines what percentage of music info remains audible above it and inaudible below it. Every new distortion / noise will raise it and every time a distortion / or noise is lessened, the noise floor lowers. When lower, more music info embedded in the recording becomes audible. When raised, more music info becomes inaudible. Moreover, the percentage of music info that remains audible (or inaudible) also determines the level of fidelity of that audible music info.
Surely you know that every last component, cable, and connection simply raises the noise floor and it ain't little. And component price matters not because the most severe distortions are universal.
If you understood the origins of several of the most significant distortions that severely cripple our sensitive instruments' (regardless of price) precision and accuracy (that are far more severe than perhaps all other distortions combined,) and how they can be remedied or absolutely minimized and thus allow most any component to perform at such levels of musicality even the component manufacturers couldn't believe, you never would have made such statements.
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I don't think noise floor is the main problem with a system's lack of resolution, ime it's usually the choice of passive parts that degrades the signal, usually a warm distortion or some sort of harshness. Interconnect cables are often one of the biggest offenders...
I'm looking at it from a DIY perspective to see if it merits further investigation or not, probably a simple project like this;
http://projectgallery.parts-express.com/speaker-projects/dml-flat-pannel/
david
This is even simpler, don't want to spend any real time until I know if I have any use for it.
david
PS. Edit- If needed just add a basic HT sub for a quick test, no need to get too involved at this point.
Yea but in all my listening to DML examples on Youtube they all seem to lack presence (including your link). This seems to be a characteristic of them as stated in that Parts Express doc "There is a lack of presence and a sensation that the sound is coming from the back of the speaker, through the panel, then finally to the listening position. This took many hours of listening to adjust to."
The link I gave doesn't have this characteristic sound, probably because of the slit between the two DML panels where HF is emitted which gives the perception of presence?
But I understand that you want something quick & easy to evaluate the concept
Your link has a woofer this one doesn't that's why I mentioned addition of an HT sub just to see what we get. If any good the first thing that has to go is that foam which robs the life out of anything. Notice the heavy curtains behind the speakers, they're also stealing life from whatever is going on in this video. Recording seems to be done from a distance with insufficient volume, can't judge anything about from this video. I like it because it saves me from building a frame at this point.
david
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