which speaker is good on classical music?

[Spkr_Bldr]

Do you mean this thing?

http://www.hiendfi.com/phpBB2/viewtopic.php?t=958

If so, I don't think it qualifies as a full-range driver omnipolar, like TLS guy meant, since it has 3 driver types(woofer, midranges and tweeters).

I also seriously doubt this unit could come close to my standards. Looks to have standard highly resonant cabinets, and I can't imagine the response of those drivers is very linear, nor very consistent on and off axis. I have not seen measurements, but based on my experiences/trials, I am speculating; which is all I can do without credible 3rd party measurements.

If you mean a different speaker system, please correct me.

-Chris

You have to remember the Shanahan is 20+ years old, it's a legend in it's own right. And still today it holds up pretty well. Of course it's not a full range single driver omni, as you know that doesn't exist. The MBL 101E is absolutely amazing though, it lives up to all the hopes of what a omni design can deliver. However it just sounds a bit weird with some music, and can create a soundstage that's completely unrealistic.

What are your standards? A cheap Infinity bookshelf lathered with plywood scraps and liquid nails? Seriously ... making judments like that based on a 5 minute Google job sounds pretty arrogant.

And what's with the use of linear to describe driver behavior? This site is the only place I've seen people use that term, but from what I gather you seem to apply it to a flat FR response. If you're meaning pistonic behavior, and assuming a relatively flat response equals pistonic, that's incorrect. What do you mean by linear, and what it supposed to imply?

 

[Cthulhu]

What are your standards? A cheap Infinity bookshelf lathered with plywood scraps and liquid nails? Seriously ... making judments like that based on a 5 minute Google job sounds pretty arrogant.

I gather his standard is this system.

http://forums.audioholics.com/forums/showthread.php?t=30467

 

[WmAx]

What are your standards? A cheap Infinity bookshelf lathered with plywood scraps and liquid nails? Seriously ... making judments like that based on a 5 minute Google job sounds pretty arrogant.

What I see is a very resonant cabinet, and some drivers firing off in different directions. The tweeters used do not appear to have any special dispersion characteristic - looks like the same little phase plugged tweeter common on many speakers. So, we have some extra tweeters on the side. I expect a response that has substantial wide dips in response starting around 30 degrees off axis, and increasing back to a flat response around 60 degrees, repeating for the front and back hemispheres. I expect a rough/resonant response - with huge ridges in the waterfall/CSD response. I don't see much of a way for this to be any different than I just stated if you measure it. If you have a source of credible measurements showing different - fine - but I am left to speculate when all I am given is a product name with no apparent thorough measured performance on an easy to find site.

And what's with the use of linear to describe driver behavior? This site is the only place I've seen people use that term, but from what I gather you seem to apply it to a flat FR response. If you're meaning pistonic behavior, and assuming a relatively flat response equals pistonic, that's incorrect. What do you mean by linear, and what it supposed to imply?

Linear is used to describe output that is accurate and proportional to input - a smooth response free of substantial peaks and/or dips; that is the meaning in terms of a FR graph. Substantial deviations of a FR are considered linear distortion. As for pistonic behavior, that is a completely different issue - but a diaphragm that remains pistonic in it's used bandwidth could in a way, be referred to as having a more linear behavior, physically. But, one can use certain drivers with relative linear FR graph - but be operating with bending modes in the passband. Many paper and poly drivers are examples of this phenomenon. Certain ceramic and metal/alloy drivers can operate very close to a pistonic action in their intended passband, however. A thorough multi-analysis of a high resolution impedance plot, a high resolution FR graph and waterfall/CSD plot can help to determine this to a point - but for absolute confidence - laser surface modal analysis is really required to find out exactly what is happening. Unfortunately, such a tool is not affordable by non-rich DIYers, and not even many speaker companies have such tools to my understanding, being more limited to the largest corporations like B&W and Harman Kardon, etc..

-Chris

 

[WmAx]

I gather his standard is this system.

http://forums.audioholics.com/forums/showthread.php?t=30467

Not really. That is an old main system - I don't even use it now. The mid to tweeter transition, and the overall tweeter axial response was not consistent enough - to meet current standards - which are extremely demanding now.

-Chris

 

[Sheep]

You have to remember the Shanahan is 20+ years old, it's a legend in it's own right. And still today it holds up pretty well. Of course it's not a full range single driver omni, as you know that doesn't exist. The MBL 101E is absolutely amazing though, it lives up to all the hopes of what a omni design can deliver. However it just sounds a bit weird with some music, and can create a soundstage that's completely unrealistic.

What are your standards? A cheap Infinity bookshelf lathered with plywood scraps and liquid nails? Seriously ... making judments like that based on a 5 minute Google job sounds pretty arrogant.

And what's with the use of linear to describe driver behavior? This site is the only place I've seen people use that term, but from what I gather you seem to apply it to a flat FR response. If you're meaning pistonic behavior, and assuming a relatively flat response equals pistonic, that's incorrect. What do you mean by linear, and what it supposed to imply?

Well, you've pretty much just shot yourself in the foot.

SheepStar

 

[3db]

Hi All,

I went down to town y'day and try to find some hifi dealers. unfortunately, they didn't carry the brand that you all mention, it is a shame. I think it is not too demanding at the local market.

The few brands I have had a chance to audit are:-

1. Quad (do not know with model)
2 Mission (do not know with model)
3. Wharfedale (do not know with model)
4. Tannoy DC4

It is quite impressive on Quad & Tannoy. Quad is slightly stronger, but the size are also bigger. Tannoy is small & cute maybe easier for me to position them. Any commend?

I really feel sorry to those who had put in a lot of afford in this thread.

Good gawd!!!, Don't feel sorry. These guys love to banter back and forth and its a learning exercise for everyone else. Its been non personlaized banter at that for the most part. ( Thank you guys for keeping it civil and allowing us to learn) Sit back, read, and learn. You've done nothing wrong by opening this thread.

 

[bandphan]

It is quite impressive on Quad & Tannoy. Quad is slightly stronger,(

Quad would be a very nice choice, Martin Logan would be another. Without going back through all this tech talk, The AV123 Strata Minis were very nice when i auditioned and the room was less the optimal. If your room is not to big, at 1100 these would be a nice choice and the quest for 1900 is as well, but being from 93 panel life could be questionable...

 

[TLS Guy]

Hi All,

I went down to town y'day and try to find some hifi dealers. unfortunately, they didn't carry the brand that you all mention, it is a shame. I think it is not too demanding at the local market.

The few brands I have had a chance to audit are:-

1. Quad (do not know with model)
2 Mission (do not know with model)
3. Wharfedale (do not know with model)
4. Tannoy DC4

It is quite impressive on Quad & Tannoy. Quad is slightly stronger, but the size are also bigger. Tannoy is small & cute maybe easier for me to position them. Any commend?

I really feel sorry to those who had put in a lot of afford in this thread.

Well, all the speakers on your list are of high pedigree. For classical music, I would recommend the Quads. I think by strong you mean the sound has proper bidy and weight. The Tannoys are more pop orientated. I have not heard Wharfedale's current offerings.

Quad have powered versions of their speakers. I would recommend those, if you can get them. You won't need amps then and can use a preamp or just use the pre outs of a receiver.

Bottom line, find room for the Quads!

 

[TLS Guy]

Good gawd!!!, Don't feel sorry. These guys love to banter back and forth and its a learning exercise for everyone else. Its been non personlaized banter at that for the most part. ( Thank you guys for keeping it civil and allowing us to learn) Sit back, read, and learn. You've done nothing wrong by opening this thread.

I think I had better go and do some honest work now. I'm off the fix a a mower!
We were off topic a bit, and so thanks for your indulgence. The OP got to audition some speakers that will fit his requirements, so all is not lost.

 

[gus6464]

Since TLS mentioned Tannoy monitors what about the Precision 8D? It has switches on the back for nearly every type of placement (far/mid/near, corner/wall/etc.) and you can download software from Tannoy which will measure the speaker and tell you the best settings for your specific room (you need a computer and calibration mic). From all of the reviews I have read of them the biggest complaint seems to be that they can be too revealing at times (not like that's a bad thing). The reviewers also mentioned that because of the tweeter being in the middle of the mid/bass driver they have a wide soundstage.

 

[Spkr_Bldr]

What I see is a very resonant cabinet, and some drivers firing off in different directions. The tweeters used do not appear to have any special dispersion characteristic - looks like the same little phase plugged tweeter common on many speakers. So, we have some extra tweeters on the side. I expect a response that has substantial wide dips in response starting around 30 degrees off axis, and increasing back to a flat response around 60 degrees, repeating for the front and back hemispheres. I expect a rough/resonant response - with huge ridges in the waterfall/CSD response. I don't see much of a way for this to be any different than I just stated if you measure it. If you have a source of credible measurements showing different - fine - but I am left to speculate when all I am given is a product name with no apparent thorough measured performance on an easy to find site.

Well, I just assumed that somebody who claims to know speakers would know and respect what the Obelisk's accomplished in 1977. I mentioned the Obelisks out of posterity, not because they represent today's state of the art ... as I said that would be the MBL 101E.

I have no idea how it would measure, not that it would really matter for Omni speakers anyway. I imagine it would be quite frustrating trying to figure out a way to measure that accurately represents performance. I'd think it would take a careful analysis of FR at the listening position with multiple mics to try and determine effects of the reverberant field and also measure in the time domain.

And since when is cross braced 1.5" thick Baltic Birch ply resonant?

Linear is used to describe output that is accurate and proportional to input - a smooth response free of substantial peaks and/or dips; that is the meaning in terms of a FR graph. Substantial deviations of a FR are considered linear distortion. As for pistonic behavior, that is a completely different issue - but a diaphragm that remains pistonic in it's used bandwidth could in a way, be referred to as having a more linear behavior, physically. But, one can use certain drivers with relative linear FR graph - but be operating with bending modes in the passband. Many paper and poly drivers are examples of this phenomenon. Certain ceramic and metal/alloy drivers can operate very close to a pistonic action in their intended passband, however. A thorough multi-analysis of a high resolution impedance plot, a high resolution FR graph and waterfall/CSD plot can help to determine this to a point - but for absolute confidence - laser surface modal analysis is really required to find out exactly what is happening. Unfortunately, such a tool is not affordable by non-rich DIYers, and not even many speaker companies have such tools to my understanding, being more limited to the largest corporations like B&W and Harman Kardon, etc..

-Chris

Ok, so your use of the term linear describes only Frequency Response and associated even order harmonics? I agree that could be descriptive when talking about measurements of raw drivers, assuming you have the necessary resolution to spot aberrations. But how can you look at those 200 pixel graphs on soundstage and apply the term linear or non-linear? And especially when talking about a finished system with unknown crossover response shaping going on, applying that term in those situations is rash and inappropriate.

You're very right about one thing, the only way to know with 100% certainty that a driver is acting as a piston is with laser surface analysis. But sure, with controlled conditions and high-resolution measurments you can tell at home.

Why your use of the term linear is confusing is this - the term non-linear regarding drivers has been used for decades by guys like Linkwitz. The simplest summary of non-linear is what happens when a driver stops acting like a piston, and the resulting energy storage, odd order and intermodulation components. But I've never seen anybody use linear to define the opposite, and for one reason. Saying linear doesn't exclude even order harmonics which are linear distortion. So calling a driver with flat FR linear and one with FR irregularities non-linear isn't accurate, a driver can easily have loads of even order harmonics and associated FR roughness and still be linear.

 

[Spkr_Bldr]

Oh, and one other question. Did you ever measure your Lineaums? I have a pair of the Aura version with the silk membrane and they measure horribly. FR is a roller coaster, and they have very high odd order and intermodulation components.

 

[WmAx]

Well, I just assumed that somebody who claims to know speakers would know and respect what the Obelisk's accomplished in 1977. I mentioned the Obelisks out of posterity, not because they represent today's state of the art ... as I said that would be the MBL 101E.

Your initial assertion was made in a way, as if the Obelisk is supposedly a good example; you provided no qualification of 'good for the era it was produced within'.

And since when is cross braced 1.5" thick Baltic Birch ply resonant?

One thing I have found, is that it's never as simple as some moderate bracing and 1 or 2" of material, to actually silence panels of a closed speaker box system. The simple addition of a proper constrained dampening layer, and use of very high density (in regards to spacing) bracing can easily remove substantial panel vibration, however. And the Obelisk did not even appear to have moderate bracing in the picture on that link; more like sparse bracing.

Ok, so your use of the term linear describes only Frequency Response and associated even order harmonics? I agree that could be descriptive when talking about measurements of raw drivers, assuming you have the necessary resolution to spot aberrations. But how can you look at those 200 pixel graphs on soundstage and apply the term linear or non-linear? And especially when talking about a finished system with unknown crossover response shaping going on, applying that term in those situations is rash and inappropriate.

My use of the term linear means whatever context is it used within. I may use it to refer to frequency response, other other issues, but it's always specified. The response plots on the Soundstage site are actually very useful - since they are non-smoothed, and cover a wide degree of off axis points. The Soundstage measurements are not complete - they need to add enclosure resonance measurements and waterfall/csd graphs - to get a better idea of the kind of behavior occuring. Also, they should ideally add a vertical response set.

Why your use of the term linear is confusing is this - the term non-linear regarding drivers has been used for decades by guys like Linkwitz. The simplest summary of non-linear is what happens when a driver stops acting like a piston, and the resulting energy storage, odd order and intermodulation components. But I've never seen anybody use linear to define the opposite, and for one reason. Saying linear doesn't exclude even order harmonics which are linear distortion. So calling a driver with flat FR linear and one with FR irregularities non-linear isn't accurate, a driver can easily have loads of even order harmonics and associated FR roughness and still be linear.

Linear distortion refers to frequency response/domain; energy storage behavior(s). Non-linear distortion refers to distortion types such as IM and THD(which are strongly connected); distortion that generates entirely new spectra.

-Chris

 

[WmAx]

Oh, and one other question. Did you ever measure your Lineaums? I have a pair of the Aura version with the silk membrane and they measure horribly. FR is a roller coaster, and they have very high odd order and intermodulation components.

I am not sure how similar the two are; the version used on the now defunct speaker linked to earlier by someone, used a mylar variant that was made in Japan. The distortion, while not ideal, never entered a level that would be audible on music program. Isolated sine waves are another issue. Frequency response of the version used, was not ideal either, and that has been fully disclosed by the person in that linked post. The 0 to 30 degree window of that tweeter, in the main part of the passband, would have a +/- 3dB variance, and it would exceed that, with narrow deep nulls starting to occur, at further angles, though the response over 7 or 8 kHz remained pretty close to the on axis response, with the main issue being, that the treble never actually reduced in level, even at 15khz more than a few dB, at extreme angles, which is the main feature that made the driver so well suited to that old application where I could not find a better omni type driver - at least not with practical access(I had tried to buy Gallo CDT tweeters for testing, but Gallo refused to sell them as parts). The Linaeum is not an easy driver to use - and I have not used it for a while - nor will I likely use it again.

I have ways to do an omnipolar-like response now including high frequency range includig 15kHz, with results keeping an extremely smooth response on and off axis at extreme angles. I have gone through several prototypes, and the final version is very close to being picked, and then built into proper finished units. But I would like to some day measure Gallo CDT tweeters - they might be a good solution. But in the past when I tried, Gallo would not sell me the CDT tweeters as parts. There are very few really good omni type solutions for high frequency drivers. Maybe MBL will sell the high frequency omni tweeter to me at a semi-reasonable cost.

-Chris

 

[Spkr_Bldr]

I am not sure how similar the two are; the version used on the now defunct speaker linked to earlier by someone, used a mylar variant that was made in Japan. The distortion, while not ideal, never entered a level that would be audible on music program. Isolated sine waves are another issue. Frequency response of the version used, was not ideal either, and that has been fully disclosed by the person in that linked post. The 0 to 30 degree window of that tweeter, in the main part of the passband, would have a +/- 3dB variance, and it would exceed that, with narrow deep nulls starting to occur, at further angles, though the response over 7 or 8 kHz remained pretty close to the on axis response, with the main issue being, that the treble never actually reduced in level, even at 15khz more than a few dB, at extreme angles, which is the main feature that made the driver so well suited to that old application where I could not find a better omni type driver - at least not with practical access(I had tried to buy Gallo CDT tweeters for testing, but Gallo refused to sell them as parts). The Linaeum is not an easy driver to use - and I have not used it for a while - nor will I likely use it again.

I have ways to do an omnipolar-like response now including high frequency range includig 15kHz, with results keeping an extremely smooth response on and off axis at extreme angles. I have gone through several prototypes, and the final version is very close to being picked, and then built into proper finished units. But I would like to some day measure Gallo CDT tweeters - they might be a good solution. But in the past when I tried, Gallo would not sell me the CDT tweeters as parts. There are very few really good omni type solutions for high frequency drivers. Maybe MBL will sell the high frequency omni tweeter to me at a semi-reasonable cost.

-Chris

Thanks for replying to this ... nothing else to add to the other discussion, trying not to derail things further than they already are.

The Gallo CDT is an interesting design, as are the MBL options. I don't see MBL selling raw drivers considering the market segment they're playing in. Maybe get in touch with Alex at RAAL. He loves working with little guys (like myself), and is a design genius. He's actually working on an incredible onmi design for this years RMAF and would certainly have some insight. He builds one-off stuff to spec too, like this 'Waterdrop'

http://www.goodsoundclub.com/GetPost.aspx?PostID=3766

Here's his info: Aleksandar Radisavljevic, info@raalribbon.com

 

[WmAx]

Maybe get in touch with Alex at RAAL. He loves working with little guys (like myself), and is a design genius. He's actually working on an incredible onmi design for this years RMAF and would certainly have some insight. He builds one-off stuff to spec too, like this 'Waterdrop'

http://www.goodsoundclub.com/GetPost.aspx?PostID=3766

Here's his info: Aleksandar Radisavljevic, info@raalribbon.com

The link was interesting, but I had to ask myself: just what is the practical bandwidth of a ribbon type driver of that type of construction/size; and further in the thread it was revealed that it's crossed around 12.5kHz, making it unusable for my purposes; the same kind of limitation I came into with other super-narrow drivers. Pioneer has some super thin radiation area ribbon hybrids - but they suffer the same problem: you must cross them at very high frequencies. Also, was revealed, these custom tweeters were about $2600. I am looking for price feasibility. If I spend that much, I can promise you I won't buy the tweeters, I will make them myself. That price range alllows me to be the necessary desktop CNC gear to start fabricating frames/assemblies for ribbon tweeters.

In my search, I found that I also prefer the idea of being able to have a multi-mode speaker; switchable from an omni-polar type of dispersion to front hemisphere only dispersion. A 180 degree driver mounted on the front and back of a small baffle would allow such a feature/function. I have since found a driver suitable, that is only down about 3-4dB at 15kHz at +/- 75 degrees. But it still is ideally used at 8kHz and over from an ideal distortion stand point - still higher than I want to have to use. It can be used at say 4.3kHz, with some compromises and increased costs(this particular model suffers from high unit to unit variation so far as distortion performance under 8kHz - so you have to cherry pick from a large batch of units to find ones with suitable lower frequency performance).

-Chris

 

[Spkr_Bldr]

The link was interesting, but I had to ask myself: just what is the practical bandwidth of a ribbon type driver of that type of construction/size; and further in the thread it was revealed that it's crossed around 12.5kHz, making it unusable for my purposes; the same kind of limitation I came into with other super-narrow drivers. Pioneer has some super thin radiation area ribbon hybrids - but they suffer the same problem: you must cross them at very high frequencies. Also, was revealed, these custom tweeters were about $2600. I am looking for price feasibility. If I spend that much, I can promise you I won't buy the tweeters, I will make them myself. That price range alllows me to be the necessary desktop CNC gear to start fabricating frames/assemblies for ribbon tweeters.

The point isn't that specific tweeter, it's that RAAL will make one-off units for individuals tailored to your needs. $2600 is an incredibly reasonable price for that tweeter, since only one pair was ever made ... if you were looking to start a commercial offering, all the prices of the initial tooling would be offset.

In my search, I found that I also prefer the idea of being able to have a multi-mode speaker; switchable from an omni-polar type of dispersion to front hemisphere only dispersion. A 180 degree driver mounted on the front and back of a small baffle would allow such a feature/function. I have since found a driver suitable, that is only down about 3-4dB at 15kHz at +/- 75 degrees. But it still is ideally used at 8kHz and over from an ideal distortion stand point - still higher than I want to have to use. It can be used at say 4.3kHz, with some compromises and increased costs(this particular model suffers from high unit to unit variation so far as distortion performance under 8kHz - so you have to cherry pick from a large batch of units to find ones with suitable lower frequency performance).

-Chris

I've actually done quite a bit of experimenting with what you're talking about, using the speakers I took to RMAF last year.

http://www.b-p-t.com/speakers.html

The W22EX is open baffle, and I've tried quite a few different rear firing full-range/tweeters mounted right behind the waveguide. I also made a box section that I can duct tape on behind the open baffle mid to seal it off and see what effect exactly the open baffle creates.

I've found that I just don't like the ambient tweeter/full-range nearly as much. In some cases it can add to the experience, but often just makes signals that are intended to be highly localized sound much bigger and more diffuse than they should. The midrange however, signals it delivers are (much) more often than not stereo and intended to focus solidly in the middle, and vocals are meant to have a big diffuse feel. So the result an open baffle midrange creates is almost always preferable - and of course you don't have to worry about cabinet colorations either.

Now if you could just make the ambient tweeters speak to each other, and only play when they're both receiving the same signal, I imagine that would be the perfect result

 

[WmAx]

I've actually done quite a bit of experimenting with what you're talking about, using the speakers I took to RMAF last year.

http://www.b-p-t.com/speakers.html

The W22EX is open baffle, and I've tried quite a few different rear firing full-range/tweeters mounted right behind the waveguide. I also made a box section that I can duct tape on behind the open baffle mid to seal it off and see what effect exactly the open baffle creates.

I've found that I just don't like the ambient tweeter/full-range nearly as much. In some cases it can add to the experience, but often just makes signals that are intended to be highly localized sound much bigger and more diffuse than they should. The midrange however, signals it delivers are (much) more often than not stereo and intended to focus solidly in the middle, and vocals are meant to have a big diffuse feel. So the result an open baffle midrange creates is almost always preferable - and of course you don't have to worry about cabinet colorations either.

Now if you could just make the ambient tweeters speak to each other, and only play when they're both receiving the same signal, I imagine that would be the perfect result

For one, I doubt you were able to achieve near omni-polar treble dispersion throughout most of the treble range, but all you really seem said in effect was you messed with rear treble dispersion, and second, special acoustical treatments are required in the environment of an extreme wide dispersion system. One of the most important treatments, is to minimize cross channel interference in the room. I use a large absorption structure that extends from the front wall, 6 to 7 feet into the room, is about 5' wide, and a little over 4' high, that physically prevents the treble and upper mid-range from being able to cross directly from L speaker to R side of room, and vice versa. It also removes all rear cross channel reflection from the wall behind the speakers. This is just one of the acoustical treatments, but without it, coloration and imaging stability are greatly troubled in a very wide dispersion system. Such a system can 'focus' a solid image in the middle just fine, and render the different properties of recordings with little self-signature, but the room acoustics are critical - and if not addressed - it's a disaster. A more controlled directivity is usually best for most people, as they are not typically willing to put forth the level of acoustic modification of their environment that is needed to use such a system as I specified.

-Chris

 

[Spkr_Bldr]

For one, I doubt you were able to achieve near omni-polar treble dispersion throughout most of the treble range

I did at one point generate some polar response graphs using 15 degree measurement intervals over 360 degrees while using a rear mounted Aura 2" driver. Obviously there were significant differences front and rear, with the waveguide on front, but overall the response was surprisingly symmetrical. I only did vertical up and down 30 degrees while on centerline axis, but the result there was also very good.

special acoustical treatments are required in the environment of an extreme wide dispersion system. One of the most important treatments, is to minimize cross channel interference in the room. I use a large absorption structure that extends from the front wall, 6 to 7 feet into the room, is about 5' wide, and a little over 4' high, that physically prevents the treble and upper mid-range from being able to cross directly from L speaker to R side of room, and vice versa. It also removes all rear cross channel reflection from the wall behind the speakers. This is just one of the acoustical treatments, but without it, coloration and imaging stability are greatly troubled in a very wide dispersion system. Such a system can 'focus' a solid image in the middle just fine, and render the different properties of recordings with little self-signature, but the room acoustics are critical - and if not addressed - it's a disaster. A more controlled directivity is usually best for most people, as they are not typically willing to put forth the level of acoustic modification of their environment that is needed to use such a system as I specified.

-Chris

That's an interesting approach, something that would be fun to experiment with. But I'm interested in developing designs that somebody in the real world might be interested in Telling a customer they need to build a separation wall like that to use my speakers wouldn't go over to well.

 

[WmAx]

I did at one point generate some polar response graphs using 15 degree measurement intervals over 360 degrees while using a rear mounted Aura 2" driver. Obviously there were significant differences front and rear, with the waveguide on front, but overall the response was surprisingly symmetrical. I only did vertical up and down 30 degrees while on centerline axis, but the result there was also very good.

To get suitable off axis response through full range of primary audiblity(I'll accept 14kHz as the limit needed for practical purposes), approaching the omni-polar when using two in bipole, based on driver radiation area, the high frequency driver would have to be on the order of about no more than 0.3" in the horizontal axis, approximately. Also, some waveguides can really help in this manner of increasing off axis dispersion, such as the waveguide used on the tweeter of the Paradigm S8. Instead of being designed to limit dispersion(as are most guides), this one is designed to widen it. Now, the off axis amplitude level is still not at the same level as is preferred, but it's much improved over the natural off axis response of a standard 3/4" dome tweeter, as example.

That's an interesting approach, something that would be fun to experiment with. But I'm interested in developing designs that somebody in the real world might be interested in Telling a customer they need to build a separation wall like that to use my speakers wouldn't go over to well.

And thus, why I do not recommend omni-polar(even high grade ones such as from MBL) speakers to people with normal acoustics/placement intentions.

-Chris