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Old 28th December 2016, 11:39 AM   #31
wesayso is online now wesayso  Netherlands
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I'm pretty sure the late John Dunlavy would have considered the STEP to be a 'train wreck'.
I have to add that Stereophile isn't always measuring in the right spot to really 'catch' the impulse as designed.

Click the image to open in full size.

It seems they try to make up for it by exaggerating the bottom end:
Click the image to open in full size.

I can understand not wanting any latency as this set is supposed to be a play all sources kind of speaker being able to directly hook up to a TV set.

The low end delay might explain this:
Quote:
Originally Posted by Geoff, the Tonmeister
Interestingly, I have certainly heard cases where a good loudspeaker can make a recording sound worse than it is. Specifically, it is not difficult to buy home loudspeakers (or headphones) that have more bass at lower frequency ranges than some studio monitors. As a result, you might hear content or artefacts in the low end that they did not hear in the recording or mastering studios. Had they heard it there, they might have decided to remove the low end problems. A good example of this is Eric Clapton’s “Unplugged” album. This has a very low frequency ringing/rumble in it that sounds very much like the sound of a tapping foot causing a microphone stand to vibrate and shake a microphone. On “normal” loudspeakers, this is inaudible (as I suspect it was in the studios where it was recorded and mastered) but on large loudspeakers with unusually low low-frequency ranges, this is very audible, and very annoying.
Test Tracks: What not to play! – earfluff and eyecandy

I have a pretty strong low end (not as exaggerated), and have it arrive pretty much in time. For me the low rumble sounds add something positive to enhance the "live feel" of that track.
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Last edited by wesayso; 28th December 2016 at 11:41 AM.
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Old 28th December 2016, 04:36 PM   #32
mitchba is offline mitchba  Canada
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Quote:
Originally Posted by wesayso View Post
I'm pretty sure the late John Dunlavy would have considered the STEP to be a 'train wreck'.
I have to add that Stereophile isn't always measuring in the right spot to really 'catch' the impulse as designed.

Click the image to open in full size.

...
Hi Ronald, I agree and kind of surprised to see this as it is no secret what an accurate step response is. Consider an ideal speaker with a frequency response from 20 Hz to 20 kHz with some low frequency roll off as most speakers would not want to pass DC. Here is such an example using 15 Hz as the corner frequency, amplitude top chart, corresponding step bottom chart:

Click the image to open in full size.

In the step response, one can see that all frequency arrive at the same time (i.e. the vertical "step") and the decay is based on the type of cabinet alignment. Here is an example of 4 types of alignments, still with a 15 Hz corner frequency:

Click the image to open in full size.

I have time aligned my 2-ways to match the ideal step for my cabinets alignment and very happy with the results: Just purchased a pair of JBL 4722n speakers. - Page 198 - AVS Forum | Home Theater Discussions And Reviews

I am surprised at the BeoLab step response as the speakers are not time coherent. I wonder if that is the sacrifice/tradeoff with respect to beam steering...

Happy holidays, Mitch
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Old 29th December 2016, 06:18 AM   #33
David McBean is offline David McBean  Australia
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Quote:
Originally Posted by Patrick Bateman View Post
I *really* wish Hornresp had the ability to vary the output levels in the wavefront simulator.
Hi John,

I will try to include the feature in the next update, scheduled for release on New Year's Day.

Kind regards,

David
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Old 29th December 2016, 02:19 PM   #34
mayhem13 is offline mayhem13  United States
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Quote:
Originally Posted by Patrick Bateman View Post
I think waveguides are the 'gold standard' for directivity control.

The thing that's so enchanting about the Beolab 90 is that it has that 'waveguide speaker' sound, but with more spaciousness.

I'm not sure if I can describe the difference, but I'll try:

Big waveguides eliminate early reflections, and I believe this is a large part of the reason that their imaging is so pin-point. For instance, a Danley SH-50 can create a center image that's so solid, you would swear there's a speaker there. The images are solid as a rock.

Dipoles create a big spacious soundstage, largely due to reflections off the back wall I think. Cardioids are similar in nature. For instance, the Gradient Helsinki creates a very pleasant soundstage, it's big and it's spacious.

Beolab 90 seems to do both; it has that 'giant headphone' effect like the SH-50, but there's also "space" like the Gradient Helsinki.

One theory I have is that we can perceive the early reflections in a waveguide, and it reduces the soundstage size. Basically the bigger the waveguide, and the "less perfect", the more the soundstage suffers.

This is pure speculation of course. About the only evidence that it may be true is that I've noticed that waveguides that feature really clean impulse response seem to "disappear" into the soundstage better. An example of this is the 18Sound XT1086.

I wish I had some big LeCleach horns to test this hypothesis. If you look at their simulated impulse response in Hornresp, it's about as clean as it gets.

But back to the subject at hand!

Click the image to open in full size.
The Beolab 90 patent is very difficult to follow, but it's referenced Mr Stiles' Bessel patent. The B90 uses a circular array.

So...

It's possible that the circular array in the B90 is some type of improved Bessel array, possibly inspired by the Stiles array.

Click the image to open in full size.
Here's one last thing to ponder. I don't know how many of you have heard the Gallo Acoustics speakers. They come *really* close to that ideal that I mentioned, the ability to generate a rock-solid center image while also creating a big stage. Basically the best attributes of a waveguide speaker like the SH-50, along with the best attributes of a good cardioid or dipole.

Obviously, the enclosure plays a big part in this.

Click the image to open in full size.
Fujitsu's speaker also has jaw-dropping imaging. At CES last year, it was shocking that this unassuming speaker imaged better than many $100K setups. And look at it! It's basically a $15 Tymphany TG9 in an egg. It sells for $1000.

Just to be sure that I wasn't taking Crazy Pills, I 3D printed a similar enclosure, and loaded it with a Tymphany TC9. Sure enough, it sounds incredible. (Measures really great too!)

Of course there's a "but" here...

The power handling on these speakers is dreadful. Imaging in spades, no dynamics.

But a Bessel array of five drivers raises the output level by 6dB over a single driver, and the improved Bessel array described in Stiles' patent gets that even higher.
When considering directivity, I think it's critical to look at it in 'constant' instead of 'controlled' terms because at the end of the day, power response is what we're after, isn't it?

We've been using waveguides to control directivity lower in frequency to meet up with large woofers who narrow early......while smaller mids and midwoofers don't begin to beam until much higher relative to their diameter.......and the newer BMRs don't seem to beam much at all!

We know that controlling directivity below 800hz is a very difficult task and pretty much out of the realm of typical DIY circles sans the Dipole systems which introduce an entire set of new problems.

What you've observed with the small single element speakers.....I have observed the same in that they have what i 'perceive' to be fantastic imaging!......IF you're in the near/on axis sweet spot. I have a very simple MMTMM build at home using 3" midwoofers crossed to a dome at 4khz on a 4" baffle that images better than any speaker I've ever owned or listened to..........as long as I'm seated on the tweeter axis between them. There's also the very limited dynamic range of course and poor LF dynamics to consider........but I think there's much merit in looking more closely at what these small point sources do so well which begs the question about diffraction. Linkwitz himself can find no subjective reason to consider it in his designs......should we?
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Old 29th December 2016, 02:40 PM   #35
mayhem13 is offline mayhem13  United States
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......and while we're looking at this subjectively, let's consider another speaker that doesn't play the diffraction game yet is heralded for its superior imaging, the Continuum which is modeled after the LS3/5. No rounded edges, a recessed woofer and edges for direct radiators to bounce off all over the place.......yet set them 5ft apart on stands and they literally disappear into a room. There's something to be said for that. Is diffraction a good thing subjectively?.....is confusing the location service of the ear/brain function a neccessary design goal? If so, is there a frequency band where this might be more effective?.......or am I back at the psychoacoustics place?.......

Maybe, but at the end of the day I really don't care about the measures and graphs when I'm sitting down for a good listen!........and if I'm meandering about the house while listening I care even less!

I'll share my greatest listening experience which came in what many consider to be the absolute worst type of listening space and that's the old Hayden Planetarium in NYC.......a massive concrete overhead dome where the system fired up into the dome and yet the entire dome was simply illuminated with sound across the entire spectrum. No placement of instruments or voices in a particular point in space.......they were simply everywhere!.....and yet the effect was the most 3D experience I can remember. I repeated it several times with different laser light shows over the years and the effect was always the same.

And I'm fortunate in my very large shop which has an old beam timber barrel roof to have been able to recreate some of that magic by having our multipoint music service speakers fire up into the barrel. I can walk through the shop or showroom all day and it just sounds wonderful to me........the sense of space......the music all around me........

Maybe that upfiring woofer in the LXMini is doing something in the Fairfield we or Linkwitz hasn't considered?.........hmmmmmmm.
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Old 29th December 2016, 04:21 PM   #36
Juhazi is offline Juhazi  Finland
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We must remember, that useally we are discussing about loudspeakers in small rooms. Radiation pattern/diffractions in free anechoic space is one thing and interaction with boundaries of a room is another.

An interesting but very difficult topic here! Bang&Olufsen RD folks gave us a tour de force example of what can be done. Another much more simple case is Kii Audio Three acoustics
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Old 29th December 2016, 04:37 PM   #37
Patrick Bateman is offline Patrick Bateman  United States
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If you don't need the variable directivity of the Beolab 90, the Kii solution is probably more "sane." With the Kii solution, you basically have a conventional two way loudspeaker for the midrange and treble, and then a four driver woofer array is wired to produce a cardioid. (It's likely an end-fire array.)

As noted in my post from two days ago, I think the 'secret sauce' is to vary the delay. At the upper limits of the woofer array, the delay will create lobes. So at the upper limits, we use zero delay. At the lower limits, the wavelengths are long enough so that lobing isn't a problem, and then we can use quite a bit of delay.

BTW, this is why the Kii and the Beolab are very deep cabinets. The Beolab is nearly a meter deep. Even with DSP delay, physics still matters, and we can only get pattern control with a big device. If it was a waveguide it would be wide, like the Danley SH-50. Since it's an end-fire array, it has to be deep.
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Old 30th December 2016, 07:46 AM   #38
wesayso is online now wesayso  Netherlands
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Quote:
Originally Posted by mayhem13 View Post
......and while we're looking at this subjectively, let's consider another speaker that doesn't play the diffraction game yet is heralded for its superior imaging, the Continuum which is modeled after the LS3/5. No rounded edges, a recessed woofer and edges for direct radiators to bounce off all over the place.......yet set them 5ft apart on stands and they literally disappear into a room. There's something to be said for that. Is diffraction a good thing subjectively?.....is confusing the location service of the ear/brain function a neccessary design goal? If so, is there a frequency band where this might be more effective?.......or am I back at the psychoacoustics place?.......

Maybe, but at the end of the day I really don't care about the measures and graphs when I'm sitting down for a good listen!........and if I'm meandering about the house while listening I care even less!

I'll share my greatest listening experience which came in what many consider to be the absolute worst type of listening space and that's the old Hayden Planetarium in NYC.......a massive concrete overhead dome where the system fired up into the dome and yet the entire dome was simply illuminated with sound across the entire spectrum. No placement of instruments or voices in a particular point in space.......they were simply everywhere!.....and yet the effect was the most 3D experience I can remember. I repeated it several times with different laser light shows over the years and the effect was always the same.

And I'm fortunate in my very large shop which has an old beam timber barrel roof to have been able to recreate some of that magic by having our multipoint music service speakers fire up into the barrel. I can walk through the shop or showroom all day and it just sounds wonderful to me........the sense of space......the music all around me........

Maybe that upfiring woofer in the LXMini is doing something in the Fairfield we or Linkwitz hasn't considered?.........hmmmmmmm.
I'd say there's quite a difference between wanting accurate imaging or the "music everywhere" type of sound. Not saying that last type can't be satisfying or even worthy of a goal all on it's own. I've heard that type of sound in a store using PA equipment cleverly adjusted. It was like walking trough a cloud of music. Much better than any music club, Disco and what not I've ever had the pleasure of visiting.

On the topic of diffraction, sure there are area's in the FR where diffraction might not be very offensive. In stereo there are a few holes in a perfectly setup listening triangle. But when aiming for accurate imaging, I'd keep an eye on diffraction and generally don't care if someone like Linkwitz does not. He also doesn't care about time coherency and I do.

I count myself lucky that I've achieved some of the greatest listening experiences of my life right here in my own home. To achieve it I did (have to) listen to Linkwitz, and Dunlavy, Geddes, Toole and all the rest. I wouldn't even want to exclude Choueiri as he rightfully pointed out some 'real' problems as well. Many more not listed here... My personal goal: A "you are there" sound experience. Quite different from "they are here" or "music everywhere" though it has definite similarities to that last type in the listening area. If all works right you get that same engulfment of music around you, but still can place or point out each source of the sound.

This achievement from B&O is nothing but spectacular. But (if he were still around, RIP) Dunlavy would (or at least could) claim it isn't accurate and he would be right. This does not mean it wouldn't or couldn't sound spectacular. Just not accurate in a strict technical sense.

If Kii kept an eye on timing like Bruno's other project with Grimm Audio it could even be more accurate. As long as it has the balls like these B&O monsters because you would really need that bottom end too!

In the end it will always be about the speaker and room cooperating as one. B&O tried to help achieve that from a speaker point of view which is very clever. No doubt this is a new landmark achievement. I'm hoping it will put DSP on the map of valid options.
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Last edited by wesayso; 30th December 2016 at 08:02 AM.
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Old 30th December 2016, 08:18 AM   #39
Boden is offline Boden  Netherlands
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Discovered this thread a bit late, and not to disgress from the current discussion, but how do the miniature Carver CR Ribbon-sidewoofer speakers fit in here?

I could not find anything related to their technology other than the usual Carver pseudo-techbabble, so how is their design related to a Bessel/Stiles Array?

Eelco
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Old 30th December 2016, 08:52 AM   #40
wesayso is online now wesayso  Netherlands
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Any specific model number Eelco? I couldn't find much on the Carver site.

All I did find is all their speakers are self proclaimed to be excellent.
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