AudioCircle
Audio/Video Gear and Systems => Enclosures => Topic started by: ACHiPo on 2 Jun 2015, 03:44 pm
-
While fairly lengthy, this presentation by Floyd Toole to the Centre for Interdisciplinary in Music Media and Technology, is very interesting. It discusses speaker design, measurement, and techniques Toole (and Harmon) have developed that have good correlation to subjective listening results. Highly recommended.
Toole's CIRMMT Presentation (https://www.youtube.com/watch?v=zrpUDuUtxPM)
-
Really interesting, and I tend to agree with him and his methods.
But one thing that has always bothered me - if he uses a truly superior method at Harman (and I believe he did), why doesn't Harman have the best sounding speakers in the world? It seems like a better method would result in very clearly superior speakers, but I've found this to not be the case when listening to Harman stuff....
-
While fairly lengthy, this presentation by Floyd Toole to the Centre for Interdisciplinary in Music Media and Technology, is very interesting. It discusses speaker design, measurement, and techniques Toole (and Harmon) have developed that have good correlation to subjective listening results. Highly recommended.
Toole's CIRMMT Presentation (https://www.youtube.com/watch?v=zrpUDuUtxPM)
'
Thanks for sharing this.
Best,
Anand.
-
While fairly lengthy, this presentation by Floyd Toole to the Centre for Interdisciplinary in Music Media and Technology, is very interesting. It discusses speaker design, measurement, and techniques Toole (and Harmon) have developed that have good correlation to subjective listening results. Highly recommended.
Toole's CIRMMT Presentation (https://www.youtube.com/watch?v=zrpUDuUtxPM)
Thanks for the link - lots of good information.
-
Thanks for the link - good stuff.
:thumb:
Ian
-
Really interesting, and I tend to agree with him and his methods.
But one thing that has always bothered me - if he uses a truly superior method at Harman (and I believe he did), why doesn't Harman have the best sounding speakers in the world? It seems like a better method would result in very clearly superior speakers, but I've found this to not be the case when listening to Harman stuff....
I've not listened to any of their speakers lately. What didn't you like about them?
-
Really interesting, and I tend to agree with him and his methods.
But one thing that has always bothered me - if he uses a truly superior method at Harman (and I believe he did), why doesn't Harman have the best sounding speakers in the world? It seems like a better method would result in very clearly superior speakers, but I've found this to not be the case when listening to Harman stuff....
Very good point. I heard Floyd talk about 6 years ago at an AES meeting in Vancouver and felt ultimately that my time was wasted in taking the long ferry trip and the hotel. I found him long on generalities and short on creative specifics. I didn't learn much of anything new (not that I'm any authority) but nothing he said conflicted with my prior understanding. I also found it mildly interesting that he seems to have come to a conclusion similar to Dr Earl Geddes and Duke LeJeune as regards bass reproduction.
During his tenure at JBL, some good sounding speakers were developed, but mainly for the pro studio market. Examples would be the LSR 4300 and 6300 series, the new 7 series and the M2. I'm not sure if he had any direct hand in the M2 Master Reference, but that is highly regarded.
I watched the first 5 minutes of this talk and got the same impression as I did in Vancouver, but will persevere and watch more later when I have the time.
-
I've not listened to any of their speakers lately. What didn't you like about them?
Oh, they were OK, but hardly the best speakers around. That includes several of the reference level JBL's they've been showing at RMAF the past several years. They all tend toward what I call "wall of sound" type production, where sound is presented in a way that the physical space of different instruments tends to blend together. "Whitewashed" is always the term that comes to mind whenever I hear one of those speaker designs.
One thing I think is inherent in his talk, which I wish he'd focus on a bit more, is the importance of the room. He tends to attack things from the loudspeaker design side, but a lot of the stuff he does with design is to try to deal with less than ideal rooms. I think the room is by far the largest factor when it comes from deviation from accuracy. And I think that Geddes with his highly directional loudspeakers and swarm of box subs is one very good method for dealing with this rather intractable variable. On the other hand, I think Linkwitz with his focus on OB speakers and their also highly directional figure 8 radiation pattern (particularly in the bass) is also another very good option for dealing with room interaction. And of course room treatments!
-
...
One thing I think is inherent in his talk, which I wish he'd focus on a bit more, is the importance of the room. He tends to attack things from the loudspeaker design side, but a lot of the stuff he does with design is to try to deal with less than ideal rooms. I think the room is by far the largest factor when it comes from deviation from accuracy. And I think that Geddes with his highly directional loudspeakers and swarm of box subs is one very good method for dealing with this rather intractable variable. On the other hand, I think Linkwitz with his focus on OB speakers and their also highly directional figure 8 radiation pattern (particularly in the bass) is also another very good option for dealing with room interaction. And of course room treatments!
The best Tyson in all honesty is when you combine the two. And that is what I have tried to do with my own system (Directivity control along with multiple subwoofers, along with manipulating the room to your liking). It's absolutely an amazing aural experience, every day on nearly every recording. So whether it is Geddes, Linkwitz or Toole, I respect them all and take them all very seriously. And then I create my own. The only problem, is that it can get expensive. But if you are willing to DIY, you can offset a lot of the costs. What one should take home is their research. And I respect that :thumb:
Best,
Anand.
-
The best Tyson in all honesty is when you combine the two. And that is what I have tried to do with my own system (Directivity control along with multiple subwoofers, along with manipulating the room to your liking). It's absolutely an amazing aural experience, every day on nearly every recording. So whether it is Geddes, Linkwitz or Toole, I respect them all and take them all very seriously. And then I create my own. The only problem, is that it can get expensive. But if you are willing to DIY, you can offset a lot of the costs. What one should take home is their research. And I respect that :thumb:
Best,
Anand.
Agreed! There is no one perfect solution for everyone. For example, I think all 3 of them would agree that a flat frequency response and even power response are very important.
But O'Toole embraces a flat, even FR/Power Response with wide dispersion. Which works well if you are in a large room, a well treated room, or you sit near field. If you aren't able to enact those 3 things, then I think the Geddes approach of flat FR/Power Response with narrow dispersion is an excellent solution. And if you are gonna stick with boxed speakers, then multiple subs in a swarm really is the best way to get smooth, even, and detailed in-room bass. And of course Linkwitz with the OB approach is also quite directional due to the figure 8 dispersion pattern inherent with that design.
Throw in a bit of EQ to knock down the worst of the bass peaks that are left, and a bit of absorption/diffusion on the walls and you are doing better than 99% of even the audiophile population.
-
minor Tangent: I think where Geddes's and Linkwitz's methods differ the most is on the headroom. I had this conversation with Dr G at his home many years back. When Geddes and Lee did their work way back when, they realized that it was highly common for theaters to hit 120db C-weighted. Dr. Geddes was pretty adamant for including HT and concert videos in the likely source material for his speakers, so the headroom was a requirement. That excludes Linkwitz's commercial speakers, and barring massive IB sub installations, would exclude OB subs for the most part. At least, that is how best I interpreted what he was suggesting.
-
OB speakers won't hit 120db at 20hz, but then again, most box speakers won't either. So a sub is going to be needed regardless. And if you limit an OB speaker to 60hz and above, transitioning to a HT sub, you should be fine.
But I think the other aspect of your tangent is actually something that's very important and is rarely brought up in the audiophile world - sensitivity. As I've listened to the very best designs over the years, there is something that highly sensitive speakers bring to the table that mid/low sensitive designs cannot replicate - real dynamics, both macro and micro. High sensitivity speakers just seem to be able to track the smallest variation in volume as well as scale from 0 to 100 much more forcefully.
In the past, only "pro" speakers or traditional horn speakers could do that, and they often had poor tonal balance, so you had to choose - do I want nice sounding speakers or do I want dynamic speakers? One thing I really like about Geddes is he introduced a highly sensitive design that actually sounded pleasant and not harsh.
I'm not a Geddes fanboy (never even owned a pair of his speakers), but I do think we owe him a debt for helping to break down some of these categories of what a high end speaker looks like and sounds like.
-
I think the disagreement (different solutions) between Geddes and Toole on wide or narrow dispersion is very interesting. I don't yet have a confirmed opinion. I am left wondering on the differences in reverb time and room treatment solutions.
I have even more narrow dispersion speakers 60ºx60º (DSL SM60F) that I use in my HT. It results, in my room, in a more limited soundstage width, but the clarity, I surmise due to limited reflections, is uncanny, like headphones.
-
I think the disagreement (different solutions) between Geddes and Toole on wide or narrow dispersion is very interesting. I don't yet have a confirmed opinion. I am left wondering on the differences in reverb time and room treatment solutions.
I have even more narrow dispersion speakers 60ºx60º (DSL SM60F) that I use in my HT. It results, in my room, in a more limited soundstage width, but the clarity, I surmise due to limited reflections, is uncanny, like headphones.
Absolutely, highly directional speakers have a clarity and crispness that wide dispersion speakers can't match, unless you sit near field, or unless you heavily (and intelligently) treat your room.
This is exactly why I tend to like well designed OB speakers - they also give you that "headphone like" clarity due to narrow dispersion (again, if they are designed well!), but then their rear-wave uses the back wall to open up the soundstage in ways that just are not possible with box speakers.
But that's just my preference. I have friends that have box speakers in well treated rooms which sound phenomenal. They have more treatments than I do, but I think that's your trade off - any room can be made to sound good, if you are willing to invest in a lot of room treatment and are able to apply it intelligently to your space. Highly directional speakers just let you cheat a little bit and get by with less treatments, IME.
-
During his tenure at JBL, some good sounding speakers were developed, but mainly for the pro studio market. Examples would be the LSR 4300 and 6300 series, the new 7 series and the M2. I'm not sure if he had any direct hand in the M2 Master Reference, but that is highly regarded.
I watched the first 5 minutes of this talk and got the same impression as I did in Vancouver, but will persevere and watch more later when I have the time.
I'd like to hear the M2s, as I've seen several glowing reviews of them as home theater and studio monitor speakers. My experience is that monitors often don't image well (maybe what Tyson calls the "wall of sound"), but I'd definitely like to give the M2s a listen. For $12k they are a relative bargain if they're as good as Toole says.
The full video is a big investment--about 80 minutes--but I really enjoyed the content. I echo Tyson's comment about the importance of the room--I initially was going to post this in the acoustics circle, but realized it was really more of a speaker presentation.
The $1800 speakers that he references as "nearly perfect" are Infinitys (L60?) that are out of production. I'm wondering which electrostatic speaker had all the resonance issues?
-
Dr. Geddes explained that imaging is often affected by very early diffraction/reflection artifacts, thus the careful attention to waveguide mouth termination and edge roundovers. That isn't something that is often done in studio monitor type big speakers.
-
I think the disagreement (different solutions) between Geddes and Toole on wide or narrow dispersion is very interesting. I don't yet have a confirmed opinion. I am left wondering on the differences in reverb time and room treatment solutions.
I have even more narrow dispersion speakers 60ºx60º (DSL SM60F) that I use in my HT. It results, in my room, in a more limited soundstage width, but the clarity, I surmise due to limited reflections, is uncanny, like headphones.
For the record, I believe that the speakers producing the narrower sound stage are always the more accurate. Narrowness of sound stage cannot be created by speakers; width can.
-
Hi Tyson, Harman usually demos their "flagship" speakers with their "flagship" Levinson #53 switching amp. I've heard Everest with #53 once and Salon2 with #53 on a couple occasions - both unbearable. #53 is 4 switching amps per channel, dynamics are like an atom bomb and electrical damping is just too damn high for music. I thought the same as you until I finally had the privilege of hearing Salon2 with Levinson 532, their top linear amp, the real flagship, now discontinued. OMG that was really great. Music came alive and the Salons were great top to bottom. Revel is back on my speaker "to try" list. I also heard the new Performa3 208s with a couple different (non Harman) linear SS amps, that too is a great speaker. Kevin Voecks is a great designer, but system synergy is still important. You'd think an all Harman system would be pure synergy, and it is with their good sounding amps, but #53 should never be connected to a speaker, only Audio Precision tester. I'd love to hear Salon2s with the new Audio Research GS150 tube amps.
Rich
-
For the record, I believe that the speakers producing the narrower sound stage are always the more accurate. Narrowness of sound stage cannot be created by speakers; width can.
I would disagree on that. A few years ago I was at an Axpona show in Atlanta and they had saxophone groups play in one of the large conference rooms. Obviously poor acoustics but the sound was amazing, especially when the largest ensemble perform (20+ players I believe). Some sounds were spacious / wide with others very specific depending on how the horn projected. In my experience very directional speakers fall short when reproducing this kind of music. The room has to be energized to a degree in order to give you a sense of space and envelopment. With speakers that have a more narrow horizontal coverage I find the sound to be what I call "formatted" in that it's just not as realistic or engaging. Vertical coverage affects this as well but not as much as the horizontal plane.
-
For the record, I believe that the speakers producing the narrower sound stage are always the more accurate. Narrowness of sound stage cannot be created by speakers; width can.
In my case, it has a great deal to do with my particular setup and the effectiveness of dispersion control of the speakers in question. I have an acoustically transparent screen, 109" diagonal, with my speakers behind. That means my LR width is constrained to about 8' and I sit roughly 12' back. The LR and toed in so as to not illuminate the side walls. Thus my soundstage is the width of my screen. The surrounds greatly open this up, but not for stereo.
The other interesting thing about the constant directivity speakers I use it that you can't tell the distinction between the front three except for where the sound it meant to come from. That is, if I were to turn off the center, you wouldn't know it was missing. There is a ultra cohesion in the front array. But then these speakers were meant to be able to be arrayed, and that is easily confirmed. So this gives me some belief that the narrow and controlled dispersion for, at least home theater setups, is the way to go.
I am building a horn system upstairs, finally (but only after I am finished with the HT setup). The horns have narrower dispersion than most traditional speakers, so it will be interesting to see how that translates there. Right now I am just using a pair of planet 10 fonkens upstairs, which are quite nice for background listening.
-
I would disagree on that. A few years ago I was at an Axpona show in Atlanta and they had saxophone groups play in one of the large conference rooms. Obviously poor acoustics but the sound was amazing, especially when the largest ensemble perform (20+ players I believe). Some sounds were spacious / wide with others very specific depending on how the horn projected. In my experience very directional speakers fall short when reproducing this kind of music. The room has to be energized to a degree in order to give you a sense of space and envelopment. With speakers that have a more narrow horizontal coverage I find the sound to be what I call "formatted" in that it's just not as realistic or engaging. Vertical coverage affects this as well but not as much as the horizontal plane.
I think you are right. There is meant to be an appropriate reverb time in a room, so it isn't dead nor too alive. Narrow dispersion can sound a bit dead space wise, like my headphone analogy. That is why acousticians tell you not to cover all walls with treatment, only the first reflections, so the other parts can scatter sound and add to spaciousness.
I think for HT where you are employing surround speakers the narrow dispersion is a major asset, taking the room out of the picture to a large degree and allowing the surround matrix to produce the directionality and spaciousness of the audio mix. For stereo, I think wider dispersion has some merit. But then narrow dispersion speaker with rearward facing radiation like Linkwitz and Duke LeJeune have done tackled that another way. The narrow dispersion just helps a great deal on early and first reflections.
-
I would disagree on that. A few years ago I was at an Axpona show in Atlanta and they had saxophone groups play in one of the large conference rooms. Obviously poor acoustics but the sound was amazing, especially when the largest ensemble perform (20+ players I believe). Some sounds were spacious / wide with others very specific depending on how the horn projected. In my experience very directional speakers fall short when reproducing this kind of music. The room has to be energized to a degree in order to give you a sense of space and envelopment. With speakers that have a more narrow horizontal coverage I find the sound to be what I call "formatted" in that it's just not as realistic or engaging. Vertical coverage affects this as well but not as much as the horizontal plane.
Honestly Rick you can have your cake and eat it too. What I ended up doing was adding diffusion to my rear side walls and rear wall. That completely provided the 'envelopment and spaciousness' while the narrow controlled directivity design provided my 'image lock.' The reverb contributes to spaciousness and envelopment. Treating the 1st reflections with absorption with narrow controlled directivity speakers made an improvement in the space between instruments (i.e. blackness), although, the improvement was small (This is most likely due to the design of the loudspeaker itself). For my front wall ,behind the loudspeaker, I have diffusers as well, which I interchange with absorbers. The diffusers are used for 2 channel and the absorbers are used for HT.
To each their own I guess. But after having listened to numerous designs that are wider dispersion and some degree of directivity control, I only became convinced and satisfied when I started listening to speakers with narrowing and constant directivity. So my choices became limited, basically well designed waveguide based loudspeakers, or well designed OB speakers like Linkwitz latest LX series.
Best,
Anand.
-
I think Duke here on AC at Audiokinesis has done some very interesting work regarding CD/swarm based speaker systems, very much in the Geddes mold. But even MORE interesting has been his development of the LCS (Late Ceiling Splash) technology - basically it's a CD speaker firing forward, and a 2nd CD speaker firing upward. This gives the laser like focus of a traditional CD speaker, but also gives the air and soundstage width/depth/spaciousness of an OB speaker. It's really a remarkable design.
-
A good friend of mine told me that audiophiles tend to "hear with their eyes". I'm wondering how the other formats (dipole, waveguides, etc) would fare under a blind test. Last year I attended an event where most of the listening was blind except for a few guys and myself who were switching out the speakers. It was interesting to see the owners try to guess if it was their speakers.
-
A good friend of mine told me that audiophiles tend to "hear with their eyes". I'm wondering how the other formats (dipole, waveguides, etc) would fare under a blind test. Last year I attended an event where most of the listening was blind except for a few guys and myself who were switching out the speakers. It was interesting to see the owners try to guess if it was their speakers.
I think a lot of it depends on the room - if it's fairly large and acoustically decent, then the OB and CD stuff becomes less important. I think the CD and OB approach are useful in situations where that's not the case. Also, if you sit near field, then the room matters less. But if you sit far field and in an acoustically challenging room, then these other approaches become very useful.
For myself, I love blind testing - it really does separate what's truly audible from what is not.
-
I would disagree on that. A few years ago I was at an Axpona show in Atlanta and they had saxophone groups play in one of the large conference rooms. Obviously poor acoustics but the sound was amazing, especially when the largest ensemble perform (20+ players I believe). Some sounds were spacious / wide with others very specific depending on how the horn projected. In my experience very directional speakers fall short when reproducing this kind of music. The room has to be energized to a degree in order to give you a sense of space and envelopment. With speakers that have a more narrow horizontal coverage I find the sound to be what I call "formatted" in that it's just not as realistic or engaging. Vertical coverage affects this as well but not as much as the horizontal plane.
I can see we fundamentally disagree on this. In my experience, the most convincing re-creations of the recording space, if there is one, have been from listening in a nearly anechoic environment, i.e., outdoors over an acoustically absorbent surface (a lawn).
Finally, in my books the ultimate test for effective speaker configuration/acoustic environment arrangement is a simple as playing a true mono signal. If the result is a sharply defined, very narrow central image then all is probably well in the spatial department. In my experience, again, almost no set up I've heard does at all well on this test. If your set up in mono cannot produce a sharp phantom image, how can you expect it to reproduce an accurate "sound stage" in stereo? Another complication is the very poor quality of most "stereo" recordings - most even orchestral recordings are the result of somewhat arbitrarily positioned spaced omni mics, even for the primary array; in more correct terms 'A-B stereo' as opposed to X-Y (coincident). Accurate image placement in this type of recording - and for many this is their only experience of 'stereo' - is just plain not there, so people do not know what they are missing.
A seasoned listener and talented amplifier designer, a former member of this group now dead (Dan Banquer, RIP) told me up until he positioned his speakers as I suggested and played my orchestral recording he had never heard stereo before. He thanked me profoundly for 'enlightening' him. He said his engineer friends went 'bonkers' when they heard it. Yes, there is life beyond what is sold as 'stereo'.
What everyone is experiencing is a wash of sound with some sort of spatial differentiation and that's enough (and perhaps it should be) but that is not what serious engineers and listeners call "Real Stereo".
http://www.tnt-audio.com/topics/realstereo_list_e.html
-
Honestly Rick you can have your cake and eat it too. What I ended up doing was adding diffusion to my rear side walls and rear wall. That completely provided the 'envelopment and spaciousness' while the narrow controlled directivity design provided my 'image lock.' The reverb contributes to spaciousness and envelopment. Treating the 1st reflections with absorption with narrow controlled directivity speakers made an improvement in the space between instruments (i.e. blackness), although, the improvement was small (This is most likely due to the design of the loudspeaker itself). For my front wall ,behind the loudspeaker, I have diffusers as well, which I interchange with absorbers. The diffusers are used for 2 channel and the absorbers are used for HT.
To each their own I guess. But after having listened to numerous designs that are wider dispersion and some degree of directivity control, I only became convinced and satisfied when I started listening to speakers with narrowing and constant directivity. So my choices became limited, basically well designed waveguide based loudspeakers, or well designed OB speakers like Linkwitz latest LX series.
Best,
Anand.
I would love to visit sometime and hear your system.
-
A good friend of mine told me that audiophiles tend to "hear with their eyes".
I think there is a lot of truth to that statement. I am still in my 30's (at least for a couple months) but I feel like I am getting old and jaded with this hobby. Certainly I've become much more of an objectivist, or at the very least put things into what I think are the priorities (acoustics/speakers >>> cables and tweaks) and spend effort and money accordingly.
I mean the hobby seems to focus and pride itself on being able to hear the subtlest minutia, presumably with the hopes that numerous small changes add up to some grand nirvana of sound. But I think many/most of these differences counteract the others, except for the ones we can objectively measure and analyse so we can shape the system as a whole.
I'd trust my ears if something measures better but sounds really off (can't say that has ever really happened in my experience) but I'd want to know what was going on, so I wouldn't just give up on the measurements. I also recognize that biases are hugely impactful on our perception. To deny such or to think you are impervious to biases is foolhardy. This is where at least some controlled blind testing of sorts helps a lot. At least you know where you are susceptible.
-
I think there is a lot of truth to that statement. I am still in my 30's (at least for a couple months) but I feel like I am getting old and jaded with this hobby. Certainly I've become much more of an objectivist, or at the very least put things into what I think are the priorities (acoustics/speakers >>> cables and tweaks) and spend effort and money accordingly.
I mean the hobby seems to focus and pride itself on being able to hear the subtlest minutia, presumably with the hopes that numerous small changes add up to some grand nirvana of sound. But I think many/most of these differences counteract the others, except for the ones we can objectively measure and analyse so we can shape the system as a whole.
I'd trust my ears if something measures better but sounds really off (can't say that has ever really happened in my experience) but I'd want to know what was going on, so I wouldn't just give up on the measurements. I also recognize that biases are hugely impactful on our perception. To deny such or to think you are impervious to biases is foolhardy. This is where at least some controlled blind testing of sorts helps a lot. At least you know where you are susceptible.
I agree with both you and Rick regarding 'hearing with our eyes.' In Floyd's presentation which the OP so kindly posted, he showed how drastically different listeners rated speakers based on 'looks' versus being truly blind. FWIW, I think waveguide based speakers look very, very, very boring. Nothing amazing. Just a box with a circle on top. No fancy veneering, and no fancy talk about how the cabinet is made of an unobtanium plutonium product from planet krypton. I also listen in the dark and all my equipment is in a separate room. I find equipment to be extremely distracting to my aural experience. And yet I spend so much in my DIY builds! Why? Resale value. That's why.
Best,
Anand.
-
I think there is a lot of truth to that statement. I am still in my 30's (at least for a couple months) but I feel like I am getting old and jaded with this hobby. Certainly I've become much more of an objectivist, or at the very least put things into what I think are the priorities (acoustics/speakers >>> cables and tweaks) and spend effort and money accordingly.
I mean the hobby seems to focus and pride itself on being able to hear the subtlest minutia, presumably with the hopes that numerous small changes add up to some grand nirvana of sound. But I think many/most of these differences counteract the others, except for the ones we can objectively measure and analyse so we can shape the system as a whole.
I'd trust my ears if something measures better but sounds really off (can't say that has ever really happened in my experience) but I'd want to know what was going on, so I wouldn't just give up on the measurements. I also recognize that biases are hugely impactful on our perception. To deny such or to think you are impervious to biases is foolhardy. This is where at least some controlled blind testing of sorts helps a lot. At least you know where you are susceptible.
One reason I really liked going "active" for several years is I was able to spin up substantial changes to my speakers with the click of a button and do real time listening comparisons between different crossover choices and different EQ choices, and it's pretty interesting what was audible and what really wasn't. The DCX was my first box, then the DEQX I ran for a few years till moving on to the miniDSP stuff. Each one I used with a couple different boxes and a whole lot of different drivers. Being able to swap things around and adjust them to your environment and tastes was really enlightening.
A few things it taught me -
1. phase matters
2. Shallower crossover slopes sound better than steeper crossover slopes.
3. Crossover points matter a whole lot.
4. Driver size plays a large role in off-axis power response
5. EQ can help but only if used in small/limited doses
6. Some room problems, such as unevenly loaded bass, cannot be solved with an EQ with box speakers
7. Etc...
Because you could load up different presets/configurations in the active crossover unit, you could very quickly cycle between different settings for your speakers and hear very clearly what they sounded like with different choices.
-
Without getting too far off-topic, I highly recommend you have a read on diyaudio, a thread about quasi-optimal crossover designs. It was probably one of the most enlightening things I have read on the subject (I haven't done a lot of xo work). Active/digital/brickwall filters still don't cheat the physics, so understanding all the variables in play helps a lot. I think this might shed a lot of light on the why your conclusions are what they are, also how to deviate from that while still obtaining as good of results.
http://www.diyaudio.com/forums/multi-way/231594-quasi-optimal-crossover-high-efficiency-loudspeaker-system.html
It has been demonstrated that it is impossible to obtain: (A) perfect acoustic summing (flat frequency response), (B) perfect phase match AND (C) flat Group Delay using a simple analogue passive crossover [Vanderkooy, J. and Lipshitz, S. P., “Is Phase Linearization of Loudspeaker Crossover Networks Possible by Time Offset and Equalization?”, J. Audio Eng. Soc., vol. 32 (Dec. 1984)].
(5)
Given (3) and (4) above, a number of efforts have been made to design "quasi-optimal" crossovers that strike the best possible balance between the three goals (A),(B) and (C) (rather than only considering (A) - e.g. conventional 3rd order Butterworth, or (A)+(B) - e.g. even-order Linkwitz-Riley).
-
Nice link! They have a bit of added complexity due to focusing mainly on horns.
For a non horn speaker, something like the miniDSP is nice because you can simply dial up different crossover points and slopes and actually measure the results from a phase standpoint, and do it iteratively to see if the theory matches practice. Also you can deal with group delay separately from phase because the miniDSP has a separate digital delay function tied to each individual driver.
What I've noticed is that phase is reasonably easy to deal with when using a lower order filter, but goes all to hell when using higher order filters. Now, a steep filter is nice because it allows you to have a clean frequency response transition so it's ideal for people that feel phase is not audible. For myself, I like the idea of steep filters, but they always sound lifeless and sterile when I actually use them.
-
SL has picked up Dr. Toole's recent talk and provides his input: http://www.linkwitzlab.com/links.htm#Toole
Best,
Anand.
-
Nice link! They have a bit of added complexity due to focusing mainly on horns.
For a non horn speaker, something like the miniDSP is nice because you can simply dial up different crossover points and slopes and actually measure the results from a phase standpoint, and do it iteratively to see if the theory matches practice. Also you can deal with group delay separately from phase because the miniDSP has a separate digital delay function tied to each individual driver.
What I've noticed is that phase is reasonably easy to deal with when using a lower order filter, but goes all to hell when using higher order filters. Now, a steep filter is nice because it allows you to have a clean frequency response transition so it's ideal for people that feel phase is not audible. For myself, I like the idea of steep filters, but they always sound lifeless and sterile when I actually use them.
I am not an expert on the matter, but to my understanding the problem with steeper filters and phase has to do with the rolloff of the actual driver with the filter in place doesn't match the textbook roll off, usually because drivers don't have perfect response. Their impedance plots aren't perfectly smooth. They have breakups, notches, etc that need to be accounted for in the steeper filter to match the textbook. Then and only then is the phase more idealized. This is why off the shelf xo filters don't work well.
The link does use horns and is focused on passive, but the freedom provided by the horns is the physical offset flexibility. But in a box world, you could build a non-standard box to offset the drivers or with the aide of digital xos, delay the needed driver to compensate for the offset. That is why I pointed out the thread. It is a seriously useful thread regardless of whether you are using horns or not.
-
SL has picked up Dr. Toole's recent talk and provides his input: http://www.linkwitzlab.com/links.htm#Toole
Best,
Anand.
I somehow always forget to go back to Linkwitz's page for updates. There are some really good links on that page!
-
I somehow always forget to go back to Linkwitz's page for updates. There are some really good links on that page!
I hadn't visited before it was referenced on this link, but I agree. Lots of good stuff there. I'd like to hear his designs one of these days--they seem to incorporate the backsplash idea that Duke's getting raves about.
-
Honestly Rick you can have your cake and eat it too. What I ended up doing was adding diffusion to my rear side walls and rear wall. That completely provided the 'envelopment and spaciousness' while the narrow controlled directivity design provided my 'image lock.' The reverb contributes to spaciousness and envelopment. Treating the 1st reflections with absorption with narrow controlled directivity speakers made an improvement in the space between instruments (i.e. blackness), although, the improvement was small (This is most likely due to the design of the loudspeaker itself). For my front wall ,behind the loudspeaker, I have diffusers as well, which I interchange with absorbers. The diffusers are used for 2 channel and the absorbers are used for HT.
To each their own I guess. But after having listened to numerous designs that are wider dispersion and some degree of directivity control, I only became convinced and satisfied when I started listening to speakers with narrowing and constant directivity. So my choices became limited, basically well designed waveguide based loudspeakers, or well designed OB speakers like Linkwitz latest LX series.
Best,
Anand.
I agree.
One system I got to hear recently was big Focals in Boulder Amplifier's listening room at their factory. It's a VERY damp room and the result was sound similar to what you'd hear from a speaker with controlled directivity. And, they sounded amazing... better than I've ever heard Focal speakers sound at a show, by a long shot.
Like most things, either wide or narrow dispersion speakers can be setup to sound excellent, it's all in the implementation. However, it's pretty common to see wide dispersion speakers used in rooms that would work much better with narrow dispersion speakers, there is something to be said for the lesser quantity of room treatments required.
-
Hey guys, I don't post much here but thought I'd throw in my 2c anyways....
I am not an expert on the matter, but to my understanding the problem with steeper filters and phase has to do with the rolloff of the actual driver with the filter in place doesn't match the textbook roll off, usually because drivers don't have perfect response. Their impedance plots aren't perfectly smooth. They have breakups, notches, etc that need to be accounted for in the steeper filter to match the textbook. Then and only then is the phase more idealized. This is why off the shelf xo filters don't work well.
Exactly! I use active myself. When done correctly I can get good phase tracking on both sides of the xo for nearly an octave with 6th and 8th order acoustic slopes. Phase can be dealt with in brick wall filters using FIR dsp. Whatever slope provides the best blend at all off axis angles is what "sounds best" to me.
I'd also like to point out that there's been talk about dipoles being narrow directivity.....IMO they really aren't. If they are working perfectly as a dipole then you have a 120 deg front and rear pattern which can be wider than a typical cone and dome type speaker in the top octaves. The M2 is also about a 120deg pattern. If you do a drawing of a speaker like a dipole or the M2 in a small room and start laying out the angles you will see what I mean about 120deg being wide wrt to the energy being directed at the side walls, and potentially the front wall depending on toe in.
To me narrow directivity (90deg or less) speakers excel in a typical small, untreated, or minimally treated, room. A constant directivity type speaker can be toed in so that the contralateral reflection occurs late enough to help with spaciousness without coloring the first arrival. My speakers are about 110deg in the lower midrange transitioning to a large wg which is around 80deg average. I get precise imaging and good spaciousness. IMO too much spaciousness due to my narrow room so I'm working on some narrower pattern speakers.......
-
I think Duke here on AC at Audiokinesis has done some very interesting work regarding CD/swarm based speaker systems, very much in the Geddes mold. But even MORE interesting has been his development of the LCS (Late Ceiling Splash) technology - basically it's a CD speaker firing forward, and a 2nd CD speaker firing upward. This gives the laser like focus of a traditional CD speaker, but also gives the air and soundstage width/depth/spaciousness of an OB speaker. It's really a remarkable design.
Thank you very much!
I've learned from Toole and Geddes both, and also Roger West of SoundLab. His big electrostats seemed to me to be doing more right than could be explained without really taking their radiation pattern into account, which was a 90 degree pattern front and back. So my first foray into polydirectional speakers was a bipolar that borrowed from Dr. West's design in spirit at least.
Toole seems to advocate wide dispersion, with good response across maybe a 180 degree frontal arc. Conceptually Roger West was taking that 180 degrees and dividing it in two, aiming half forward and half backwards, and I emulated that.
My next step was to incorporate Toole's findings on the ideal direction for the additional reverberant energy to arrive from, which turns out to be about 60 degrees off the centerline to either side ("10 o'clock and "2 o'clock"). That was an improvement in rooms that allowed the placement needed, but such rooms were rare.
My friend Jim Romeyn was experimenting with various bipolar configurations, having heard some merit in my designs. He was using multiple mini-monitors, and at one point tried the upfiring configuration that became the Late Ceiling Splash we now use. While not giving us the ideal direction for the additional reverberant energy, the path length was longer in most rooms, and apparently the greater path length made more of a difference than getting the direction just right. Of course this is based on far less rigorous testing than what Toole would have done!
If one has free reign to place speakers as he sees fit, and a nice big room, a bipolar may make the most sense (well, to me and those drinking the Kool-Aid that I serve). But in most rooms, I think the LCS is the preferred configuration.
Swing by our room at RMAF, we plan to show the Swarm with dedicated satellites, along with a more adaptable LCS module.