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I'm going to try more placement adjustments today. Then room treatment. Any form of EQ will be last. It's not that I'm anti-EQ; it's simply that EQ has some pretty strong limitations and I'm sure to be better off working on the physical space before manipulating frequency response.
What are the dimensions of your room? Is it open or closed? Do you have (a) subwoofer(s)?
 

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Dear Dr. Toole, although one wouldn't need a double blind test to tell that those Yammy NS1000s are indeed bright sounding ;)(again, just how much is largely dependent on the kind of amplification used), the big 11.8in paper woofer crosses over to the beryllium midrange dome @ 500Hz (not 1kHz), which in turn extends its operation range up to 6kHz, allowing a very soft transition to the beryllium tweeter. Thus, being it a dome and a dome of such rigidity and lightness, one should have expected a very good/even sound dispersion characteristics and, hence, a very good off-axis frequency response in that range from a relatively small (only 3.5in) midrange dome.

What exactly made the NS1000 not as flawed as the NS10M (?), since they both had the same target performance - a flat sound power, as you say. Beryllium anyone?!:D

I'm sure that if Kevin Voecks and Mark Glazer had that beryllium midrange dome at their disposal, theirs and their team's enginnering effort would be greatly reduced. I guess one had to be an awful engineer to mess up a speaker design having such good drivers.:)


BTW, now that I'm on this, I must say I have the answer to a better Salon design, being it a cost no object loudspeaker... The Salon3 should have carbonfiber drivers instead of metal ones!!! In fact, I don't understand why isn't such a readily available material nowadays used for loudspeaker drivers manufacturing. Carbonfiber is getting increasingly cheaper, even my sports salo(o)n have it all over the place! Very stiff, very light and easily modulated intrinsic damping characteristics. No metal, can touch it, not even beryllium!

Harman must now pay me for such brilliant idea!:D
It seems that you don't have my book to refer to. If you could look at the anechoic curves in Figure 18.3(e) you can easily see that the large woofer is having a significant effect up to 1 kHz on axis and contributing to a sagging off axis performance between 500 Hz and 1 kHz. The network may be trying to shut the woofer off at 500 Hz, but acoustically it is still a dominant factor for most of the next octave. Their goal of flat power response required them to let that part of the axial frequency response be elevated - resulting in the midrange coloration.

The problem with the NS10M had nothing to do with a lack of beryllium and everything to do with the directivity of 7-8 inch two-way loudspeakers, as was clearly shown in Figure 12.10.

Beryllium pushes the diaphragm breakup modes high in frequency, allowing the operational frequency range to be expanded. Other materials can work perfectly satisfactorily over more limited frequency ranges. Its low mass helps efficiency, which is also good. However, the directivity is determined by dimensions, not materials.

As for other diaphragm materials, there are several that would be attractive if they could be manufactured with sufficient consistency - fiber reinforced matrix cones are not new, kevlar and carbon being two options, but there are others, some involving nano technology I have heard. With premium Revel speakers aiming for 1 dB production consistency, end of line testing and tweaking are necessary and costly. Consistency, cost and complexity (and safety) are major issues. Making car bodies is not as demanding as making cones and domes, and even there human oversight is often required in the laying up of the fibrous material.

Engineers at Harman created one of the better new ones, called the ceramic metal matrix diaphragm, CMMD. It is deep anodized aluminum, creating exterior layers with ceramic stiffness and an interior of aluminum for damping. Low mass, high stiffness, easy to manufacture, and inexpensive (compared to beryllium to be sure). Varying the depth of anodization permitted its wide use in affordable speakers, including in cars, while deeper anodization worked well in premium products (the Infinity Prelude MTS, for example, which had no mechanical resonances within its operational range). It remains an option for all products.

We await the widespread availability of 'Unobtanium" which we hear beats them all. Meanwhile, the choice of diaphragm materials involves tradeoffs. People get enthused about materials, when the real issues often relate to the design of the motors - efficiency, power compression, non-linear distortion, etc. - which are hidden virtues or problems. When the performance of loudspeakers has plateaued at a high level it is not uncommon to seek out different, exotic sounding materials just to be different. Differentiation becomes a marketing issue.

Fortunately, with adequate anechoic data it is possible to anticipate the sound quality from loudspeakers - whatever materials are used.
 

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It seems that you don't have my book to refer to. If you could look at the anechoic curves in Figure 18.3(e) you can easily see that the large woofer is having a significant effect up to 1 kHz on axis and contributing to a sagging off axis performance between 500 Hz and 1 kHz. The network may be trying to shut the woofer off at 500 Hz, but acoustically it is still a dominant factor for most of the next octave. Their goal of flat power response required them to let that part of the axial frequency response be elevated - resulting in the midrange coloration.

The problem with the NS10M had nothing to do with a lack of beryllium and everything to do with the directivity of 7-8 inch two-way loudspeakers, as was clearly shown in Figure 12.10.

Beryllium pushes the diaphragm breakup modes high in frequency, allowing the operational frequency range to be expanded. Other materials can work perfectly satisfactorily over more limited frequency ranges. Its low mass helps efficiency, which is also good. However, the directivity is determined by dimensions, not materials.

As for other diaphragm materials, there are several that would be attractive if they could be manufactured with sufficient consistency - fiber reinforced matrix cones are not new, kevlar and carbon being two options, but there are others, some involving nano technology I have heard. With premium Revel speakers aiming for 1 dB production consistency, end of line testing and tweaking are necessary and costly. Consistency, cost and complexity (and safety) are major issues. Making car bodies is not as demanding as making cones and domes, and even there human oversight is often required in the laying up of the fibrous material.

Engineers at Harman created one of the better new ones, called the ceramic metal matrix diaphragm, CMMD. It is deep anodized aluminum, creating exterior layers with ceramic stiffness and an interior of aluminum for damping. Low mass, high stiffness, easy to manufacture, and inexpensive (compared to beryllium to be sure). Varying the depth of anodization permitted its wide use in affordable speakers, including in cars, while deeper anodization worked well in premium products (the Infinity Prelude MTS, for example, which had no mechanical resonances within its operational range). It remains an option for all products.

We await the widespread availability of 'Unobtanium" which we hear beats them all. Meanwhile, the choice of diaphragm materials involves tradeoffs. People get enthused about materials, when the real issues often relate to the design of the motors - efficiency, power compression, non-linear distortion, etc. - which are hidden virtues or problems. When the performance of loudspeakers has plateaued at a high level it is not uncommon to seek out different, exotic sounding materials just to be different. Differentiation becomes a marketing issue.

Fortunately, with adequate anechoic data it is possible to anticipate the sound quality from loudspeakers - whatever materials are used.
Dr. Toole, I have heard some say that beryllium is not as well suited for a midrange compared to ceramic due to the fact that it's not internally damped, would such low level resonances be audible or do you think it's inaudible as long as there are no FR peaks associated with such ringing?
 

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But Dr. Toole the only thing memorable about the NS1000 was its Beryllium drivers. Why?

Not just because they were exotic stuff! As I've said, beryllium made possible to manufacture a midrange dome of 3.5in capable of operate from just below 500Hz to above 6kHz.

As you say, directivity is determined by dimensions and I'll also add shape. A dome is omnidirectional provided it doesn't start to exhibit breakup modes! That's what characterizes dome tweeters. Now try to produce a dome that is able to operate in such wide frequency range at 90dB (1m, 1 watt) with materials other than beryllium. ATC being able to produce a proper 75mm (3in.) soft dome mid-range driver is some sort of engineering miracle (but it doesn't go as high in the frequency range nor it has the same efficiency)! Midrange transperancy is greatly enhanced with such dome drivers and I bet beryllium has the edge (pun intended) over textile domes. Isn't that why Revel uses metal drivers after all?!

Two-way loudspeakers, by definition, don't benefit of such midrange dome, so for every two-way design there will always be that inherent limitation, which will always be their biggest enginneering challenge if one wants decent bass output.

I guess that paper simply wasn't good enough of a material for such big cone and made it even worse in the NS10M! Monitor Audio latest Silver 100s are a two-way design with a 8" woofer and an even higher crossover point (2.8kHz against 2.0kHz of the NS10M) and don't sound remotely as bad.

But I'm sure that a beryllium tweeter would have allowed to lower the crossover frequency in the NS10M (as it happens w/ Revel Performa Be models range) and therefore would have helped to mitigate the phenomenon.

Oddly enough, when using the NS10M "recording engineers sought to dull its treble response by hanging tissue paper in front of it, resulting in what became known as the "tissue paper effect".

As for the driver motors, stiffer, lighter driver materials allow the usage of bigger, more powerful motors for the the same (or less) driver net weight, which helps heat dissipation, meaning they run cooler and hence with less heat compression at high SPLs, while keeping efficiency by virtue of the reduced weight.

On the other hand, one can see in the NS1000M owner's manual how the elevated axial frequency response can be tamed with the level control set to -3dB.

Finally, the same way smartphones, laptops and the likes have paved the way for electric cars with the battery tecnhology becoming increasingly better and cheaper, I also believe that automotive industry will help carbon fiber to be readily available for many other applications at a competitive cost, such as loudspeakers drivers!


Revel Salon3 CF... sounds goooood!!!:D
 

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Dr. Toole, I have heard some say that beryllium is not as well suited for a midrange compared to ceramic due to the fact that it's not internally damped, would such low level resonances be audible or do you think it's inaudible as long as there are no FR peaks associated with such ringing?
These days it is possible for transducer engineers to predict, using computer models, cone or dome behavior with impressive accuracy. The material is just the starting point. The thickness, the profile of the radiating surface, how the perimeter is terminated, etc. all factor into the performance. The general idea is not to have any resonances within the operating bandwidth of each transducer. Usually this is achieved by moving the first breakup mode well above the upper operating limit, leaving essentially pistonic behavior. If a resonance remains within the operating range, its audibility must be evaluated. All of this is visible in high resolution anechoic measurements - if there is a bump, and the bump persists through spatial averaging over large solid angles, it is a resonance. The next action is to determine, based on existing detection threshold data, whether the residual resonance is audible. These days achieving functionally resonance-free performance is possible.

For a given operational bandwidth several materials may be comparably satisfactory. They will differ in cost, consistency and mass (efficiency), but may all sound the same. Beryllium is attractive for tweeters because these days "ultra wide bandwidth" is a popular interest, and selling point, whether it is audible or not. It may or may not be uniquely advantageous in other applications - it depends on the design intent.

Damping is not necessarily a solution. Damping a high-Q narrow resonance turns it into a lower-Q wider resonance. Strangely enough, as measured in frequency response deviations, we are much more sensitive to low-Q (wider bandwidth) resonances than we are to high-Q ones - the ones that ring energetically. Why? Because they are narrow band they are less likely to be energized by music. A Q=50 resonance can show a 10 dB peak, a narrow spike in the frequency response, before it is audible in typical pop music. There is truth in the old expression "good enough for rock and roll" :) In contrast, we can detect low-Q humps of much less than 1 dB with high spectral density sounds like pink noise. This is why specifications like +/- 3 dB are a joke. It is why loudspeakers that "measure the same" sound different. They probably are. Chapter 4 in my book discusses resonances, and Figure 4.10 shows this dramatically.

Incidentally, we don't hear the ringing. We detect the amplitude response bump. It is all discussed in peer reviewed AES papers and in my books.
 

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Take note that with a dome midrange transducer with such characteristics due to beryllium, as found in the Yamaha NS1000, a lens to limit the dispresion characteristics of the tweeter dome and the waveguide to boost its output at the crossover frequency, in order to match those of the conventional mid/bass cone, would have been rendered useless! Simply because this time there is two domes, mid-range and tweeter, running with identical behaviour. Also, high-order crossovers could be replaced by simpler ones, with more gentle slopes, which means less electric parts and greater signal integrity.


Off-axis frequency response would be therefore greatly enhanced and the engineering effort to attain it, without all the added complexity, greatly reduced.


That's its beauty!
 

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NullTest said:

"Not just because they were exotic stuff! As I've said, beryllium made possible to manufacture a midrange dome of 3.5in capable of operate from just below 500Hz to above 6kHz." As the measurements show: they get a lot of help from the woofer up to about 1 kHz. It certainly is not bearing the full load above 500 Hz. I'm not belittling Be, just keeping the facts straight

"A dome is omnidirectional provided it doesn't start to exhibit breakup modes! That's what characterizes dome tweeters." A pulsating dome may be omnidirectional, but a rigid one cannot be. At wavelengths approaching and above the diameter they beam and, depending on the shape of the dome and the behavior of its surround, there may be interference effects. Again, don't trust me, look at the data.

"I guess that paper simply wasn't good enough of a material for such big cone and made it even worse in the NS10M! Monitor Audio latest Silver 100s are a two-way design with a 8" woofer and an even higher crossover point (2.8kHz against 2.0kHz of the NS10M) and don't sound remotely as bad." My guess is that the Monitor Audio was designed with a flattish on-axis response, not sound power. It would have to sound better. BTW, treated paper cones can be remarkably good - see the JBL Pro M2.

"Oddly enough, when using the NS10M "recording engineers sought to dull its treble response by hanging tissue paper in front of it, resulting in what became known as the "tissue paper effect". Yes that is so, but there is some confusion. The original NS10M exhibited a much elevated tweeter level relative to the woofer (Figure 12.10). It was designed as a consumer product to be placed against a wall (bass boost)and listened to at a distance (attenuated midrange boost). However, placed on the meter bridge of a recording console it was Bright! So, hang some tissue paper in front of the tweeter, just as any sensible person would do - don't for goodness sake go find a better speaker. The professional version had better woofer to tweeter level balance, but there was a huge hump in the upper midrange (Figure 12.11). Tissue wouldn't help, but I know some who still used it "because".

"On the other hand, one can see in the NS1000M owner's manual how the elevated axial frequency response can be tamed with the level control set to -3dB." Unfortunately it covers far too large a frequency range, and does as much harm as good. The problem is much narrower in bandwidth.

"Revel Salon3 CF... sounds goooood!!!" If well designed, one would hope so. A little more efficiency would be good and lighter cones help. Eliminating need to reproduce the lowest bass would also help - convince people to employ bass management and spend some money on powered closed box subwoofers (2 or 4) which can address room modes - those are resonances that speaker manufacturers cannot control. Chapter 8.
 

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One other thing to do before spending a lot of time trying to optimize the Salon2's full range, is high pass them @ 80Hz and see what your room look like. Use your subs below 80 and move them around.
Ultimately, I know this is the answer. However, I don't have an immediate solution handy to HPF the Salon 2. I'm hoping to get solid enough response from the Salon 2 down to 40 hz such that, for music, my subwoofers only need to play the ultra-low fill duty. I'm not ready to give up.

What are the dimensions of your room? Is it open or closed? Do you have (a) subwoofer(s)?
Main room is 14.5' x 19.5' and its' open on the back right side into the rest of the downstairs area. Part of why I want to avoid adding a lot of expensive treatment right now is that we are going to remodel downstairs and those room dimensions are going to end up sealed.

I do have subwoofers. I want to get the best possible response from the Salon 2 before I integrate the subwoofers.
 

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Dr. Toole,

You have to decide :): Did the NS10M sounded so dreadful because of their goal of flat power response? Because of the big woofer size for a two-way design? Or both?


A pulsating dome may be omnidirectional, but a rigid one cannot be. At wavelengths approaching and above the diameter they beam and, depending on the shape of the dome and the behavior of its surround, there may be interference effects. Again, don't trust me, look at the data.
But I always trust in the man who brings reliable data!

"In God we Trust, all others must bring data” W. Edwards Deming

:D

However, you have to agree that, as far as transducer behaviour is concerned, a dome midrange of sensible size and shape will always better resemble a tweeter dome than a cone of the same radiation area as the former is able to, all other things being equal.

The problem with domes is that once they start to exhibit breakup modes there's no way to control it, as opposed to cones. That's the reason why beryllium is used here at such great effect, because being as rigid as it is, it can assure perfect pistonic behaviour for an extended frequency range.

I guess that's the reason why Focal started to use the so-called inverted dome tweeter and then they just applied their long standing technology to beryllium. It's my belief that with beryllium they wouldn't have need inverted domes in the first place...


One must admit that, the single most important progress in the loudspeakers design in the past 15 years has been the materials technology used in transducer manufacturing, greatly influenced by the increasing sophistication in software simulation.
 

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Dr. Toole,

You have to decide :): Did the NS10M sounded so dreadful because of their goal of flat power response? Because of the big woofer size for a two-way design? Or both?

.
I explained it in Figure 12.10. It is both. The size disparity at crossover creates a directivity index discontinuity. As you know, I'm sure, DI is the difference between on-axis and sound power curves. As the figure shows, if you design for flat on axis the sound power is not flat. If you design for flat sound power the on axis is not flat. You cannot have both. It turns out that the direct sound is the dominant factor in sound quality, so the sound power target loses. But, the flawed off axis performance is still heard in normally reflective rooms and such loudspeakers lose to those with a close relationship between on- and off-axis performance.

The answer to cones vs. domes ultimately comes down to which is able to deliver a better - closer - relationship between on and off axis sound radiation. The spinorama data presentation reveals it immediately.

As for the most significant technical advance in transducers - my transducer design colleagues have told my many times that it is adhesives. When you enter the power test room and voice coils are glowing cherry red and paint on magnets is bubbling it seems simply miraculous that the speakers work at all after days and days of such abuse. But they do.

All of this and more is in my book. I'm done here for now, bye. :)
 

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I explained it in Figure 12.10. It is both. The size disparity at crossover creates a directivity index discontinuity. As you know, I'm sure, DI is the difference between on-axis and sound power curves. As the figure shows, if you design for flat on axis the sound power is not flat. If you design for flat sound power the on axis is not flat. You cannot have both. It turns out that the direct sound is the dominant factor in sound quality, so the sound power target loses. But, the flawed off axis performance is still heard in normally reflective rooms and such loudspeakers lose to those with a close relationship between on- and off-axis performance.

The answer to cones vs. domes ultimately comes down to which is able to deliver a better - closer - relationship between on and off axis sound radiation. The spinorama data presentation reveals it immediately.

As for the most significant technical advance in transducers - my transducer design colleagues have told my many times that it is adhesives. When you enter the power test room and voice coils are glowing cherry red and paint on magnets is bubbling it seems simply miraculous that the speakers work at all after days and days of such abuse. But they do.

All of this and more is in my book. I'm done here for now, bye. :)

Post of the century.
 

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The answer to cones vs. domes ultimately comes down to which is able to deliver a better - closer - relationship between on and off axis sound radiation. The spinorama data presentation reveals it immediately.

The problem is that above a certain size, domes are much more difficult to make right. What does the data say?





As for the most significant technical advance in transducers - my transducer design colleagues have told my many times that it is adhesives. When you enter the power test room and voice coils are glowing cherry red and paint on magnets is bubbling it seems simply miraculous that the speakers work at all after days and days of such abuse. But they do.

LOL!
 

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How does the Magico get such good off axis integration with tweeter and 6” midrange in the S5? No waveguide. NRC data:

At soundstage. Can’t post link yet.
Off axis the Magico S5 has a dip in response at 2.5 kHz which is the crossover frequency between the midrange and the tweeter. See Chart B in the link below.

https://www.soundstage.com/index.php?option=com_content&view=article&id=1043:nrc-measurements-magico-s5-loudspeakers&catid=77:loudspeaker-measurements&Itemid=153

Of course the dip isn't as pronounced as in Chart B here:

https://www.soundstage.com/index.php?option=com_content&view=article&id=1645:nrc-measurements-bowers-wilkins-685-s2-loudspeakers&catid=77:loudspeaker-measurements&Itemid=153

In the good old days, Harman could make a $1.5k, 3-way speaker with measurements like this:

https://www.soundstage.com/measurements/revel_concerta_f12/

https://www.stereophile.com/content/revel-concerta-f12-loudspeaker-measurements Well OK, at dip in John Atkinson's measurements at 2 kHz, but otherwise really smooth off axis.

Not as good as this one however:

https://www.soundstage.com/measurements/speakers/revel_ultima_salon2/
 

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Thanks @Floyd Toole appreciate it- I will add your book to my reading list :)


For Salon2 owners, you should try to passive bi-amp the speakers as @RichB mentioned in his review- to my subjective ears it made a positive difference (of course you have to weigh in if 2x amp channel is worth $$ difference or not).

Regards,
Kishore
 

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I want to get the best possible response from the Salon 2 before I integrate the subwoofers.
Since you have REW, you'll probably want to use EQ to achieve a flat bass response, in which case it will not be necessary or even ideal to aim for good response from speakers alone before going for good response from speakers + subwoofer. EQ can fix peaks but not nulls (by too much), so your ideal response is to have as much output with as few nulls as possible. You won't know exactly what the nulls are until you combine speaker + subwoofer.

Your strategy could be to place the speakers optimally for 100hz+ frequencies, and then locate the subwoofers to fill in nulls below 100hz, and then apply EQ to smooth things out.

From your measurements above it looks like you already have enough output for EQ except maybe 40-60hz.
 

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Since you have REW, you'll probably want to use EQ to achieve a flat bass response, in which case it will not be necessary or even ideal to aim for good response from speakers alone before going for good response from speakers + subwoofer. EQ can fix peaks but not nulls (by too much), so your ideal response is to have as much output with as few nulls as possible. You won't know exactly what the nulls are until you combine speaker + subwoofer.
My understanding is that this is partially correct. I suspect that I'm getting that dip (probably not deep enough to be considered a true null) due to comb filtering induced by what I guess are rear-wall reflections. While it's true that I can't EQ my way out of it, I may not be able to "subwoofer my way out" of it either. I don't want to apply EQ until I understand the cause. If I can get to better response in that 40-60hz range, I'd be very comfortable applying some EQ. My worry is that I'm already seeing strong resonance at the lower frequencies below 40hz and adding the subwoofers is going to make that problem worse. I will almost certainly need to apply EQ; but, I'll probably start with some treatment first to see if I can tame those resonances.

At the moment, I have no system for EQ available to me. Unfortunately, most MiniDSP products are not compatible with my McIntosh preamp due to the far higher voltage on the balanced outputs than most of the MiniDSP kits can handle. Most things that are compatible come with a high price tag.
 
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