Re: Re: Re: Re: Re: Directionality
But a floor reflection delayed by 10 ms !!! Thats way beyond what it would be in a small room. What you are quoting does not apply.
Using a term like RT60 implies a quantifiable reverb time, and in a small room it is so short that these concepts don't apply.
Virtually none of the concepts and research from large room acoustics applies to a small room. I hope that you are not making the mistake of thinking that they do.
DDF said:
But a floor reflection delayed by 10 ms !!! Thats way beyond what it would be in a small room. What you are quoting does not apply.
Using a term like RT60 implies a quantifiable reverb time, and in a small room it is so short that these concepts don't apply.
Virtually none of the concepts and research from large room acoustics applies to a small room. I hope that you are not making the mistake of thinking that they do.
It would be nice if the moderators could shift these last exchanges to this thread The Objectives of a Loudspeaker in a Small Room
cheers,
AJ
cheers,
AJ
Re: Re: Re: Re: Re: Re: Directionality
No, I'm well aware of the differences.
Perhaps I am guilty of stretching the application of the vertical reflection study though. However, it could reasonably apply to vertical ceiling reflections. Either way, it doesn't substantively change my argument that the floor cue is important if the goal is to create a believable ruse that the players are in your room.
gedlee said:
No, I'm well aware of the differences.
Perhaps I am guilty of stretching the application of the vertical reflection study though. However, it could reasonably apply to vertical ceiling reflections. Either way, it doesn't substantively change my argument that the floor cue is important if the goal is to create a believable ruse that the players are in your room.
DDF said:
I assess the "school" by the sound of their graduates. Although the NRC/Toole folks have been effective advocates, and there are many commercial speakers that now represent their approach, I haven't been dazzled by the results.
To me, the ones I've auditioned - at a range of price points - sounded OK. Not bad, not great, as if they were designed by a focus group to satisfy most listeners. A bit like the food in a good-quality chain restaurant. Pleasant, but ...
By contrast, the speakers I heard at the BBC Research Lab, aided by a Studer 1/2" tape recorder playing a first-generation quadraphonic mastertape, was possibly the finest and most lifelike, you-are-there sound I've ever heard. I have also had this sensation listening to Quad ESL57's with a high-quality analog system. There were moments with the Bastani Apollos that were really quite something, along with moments with the Linkwitz speakers.
When something really grabs my attention, I start asking why. I'm very Buddhist that way: I trust my perceptions, but I also want to know why I've perceived a certain set of sensations. This makes me a very dangerous reviewer: I either like or dislike a product, and if I like it, I immediately start back-engineering it and finding out what made it sound that way. This is not fair to the manufacturer, so I resigned as a Positive Feedback reviewer in the early Nineties.
Speakers are remarkably flawed in so many ways, the real question is what to optimize, and what parameters to relax. It will be a very long time until we get speakers that measure like amplifiers, so you have to pick and choose. Where the "objectivists" and I disagree is using personal esthetics to guide the choice - until some kind of audible perfection is within reach, I believe in speakers that reflect a certain esthetic, that is designed to accomplish certain goals while setting aside others.
I think that perfection is a long, long way off. Every time I go to a live concert (no amplification, thank you very much) I can't listen to hifi - any hifi - for at least a day or two afterward, the contrast is so great and so unflattering to the mechanical reproduction system.
There are entire genres of music that just don't work with hifi at any level of performance, modern classical being one. I was moved to tears listening to the Seattle Symphony perform Stravinsky's "Rite of Spring", a piece that is horribly dissonant on any hifi system. In performance, with a good orchestra in a good hall, it is inexpressibly beautiful. I never knew. None of my records or CDs sound remotely like what I heard in Seattle - and I know if I listened to a top European orchestra this piece would be even more intense and powerful.
I am dumbfounded when I hear people compare any hifi to live music. They sound completely different, as different as real-life is to a movie.
Given this vast gulf, I aim for a subjectively pleasing sound that has qualities similar to the real thing. That sounds pretty modest, and I guess it is - but even something as modest as that is pretty hard to do. Just getting rid of the grossest and most irritating colorations, along with the extremely unnatural spatial presentation of 2-speaker stereo, is no small challenge.
When I listen to controlled-directivity speakers, I hear a very closed-in, unnatural, and artificial perspective. Other people hear something completely different, and enjoy the sound of controlled-directivity speakers. I can force myself to ignore it, but the unnatural quality never goes away, and substantially detracts from my enjoyment.
In terms of spatial perspective, the most realistic sound I've heard has come from BBC-design direct-radiators or Quad electrostats, in 2 and 4-channel playback from mastertapes and occasionally LP's. Most digital seems to have a spatially truncated perspective - but high-resolution 96/24 or higher PCM seems to get closer to the mastertape sound. I'm still reserving judgement on SACD/DSD - there seems to be something wrong with single-bit conversion.
As for room size, I dunno. Bigger rooms help, but I have heard remarkable sound in small rooms, too. I really dislike dead rooms, though - they sound grossly unnatural to me. Any room where your own voice sounds weird is NOT going to be a good room for hifi listening. Conversely, if a real musical instrument, like a violin, sounds good, it's a good room.
As for the readers with small rooms, I'm actually optimistic. I've heard ESL57's sound exceptionally good in rooms that were ridiculously small, where you were practically on top of the speaker (think of the typical Brit living-room right after the war).
As for crossovers, it was Laurie Fincham that personally instructed me on the importance of phase-tracking through the entire crossover region. I take this seriously, and try and keep phase angles very carefully controlled, since this has such a strong influence on timbre, naturalness, and spatial quality. I feel this is underestimated in most commercial high-end speakers, with the result of somewhat phasey images and odd colorations in the vocal region. The fad for cookie-cutter image quality has greatly undermined the overall spatial perspective, which I feel is much more important, since it conveys a sense of "being there".
Minor Point: Floor reflections are typically delayed 3~3.5 mSec, with ceiling and sidewall reflections taking somewhat longer. And don't count on carpeting to "absorb" the floor reflection - when I measure the floor reflection by itself, it's very similar to the direct sound, with a gradual rolloff starting around 8 kHz. It takes a LOT of damping material to get a 20 dB reduction in a reflection.
MLSSA pix are here.
Re: Open Baffle
I've heard them locally at a Denver audiophile's house and a truly gigantic system at the last RMAF. Each speaker must have had a surface area the size of an SUV - it was huge partially cylindrical array, each side powered with a giant stack of Krells. I was told the system cost more than a million bucks.
Sonically? Ehhh, only just OK. Timbres sounded kind of pale, diminished and flattened out - and dynamics, despite the immense size, were just so-so, typical dynamic-speaker fare. Symphonic music just didn't have the sparkle and immediacy I expected, given the tremendous resources thrown at this system. But in all honesty, I don't think it's at all fair to assess Sound Labs based on the crazy, over-the-top RMAF demo in a huge hotel ballroom, big enough to park a semi-truck in.
(I don't think any kind of audiophile speaker works in theater-size spaces - that's what prosound systems are for.)
As for the Sound Labs at a local audiophile's house, I dunno. I didn't hear the sparkle I expected - I was a bit surprised, actually. By "sparkle" I don't mean HF extension, more a quality of liveliness and expressiveness, those little quirks of performance that makes music so enjoyable. I'd have to characterize it as a very "audiophile" kind of sound - take that for what you will.
But again, limited sample size. Just because they sounded funky doesn't mean they couldn't be terrific if used in the right way, in the right environment. But I don't know what that right environment would be, since I don't hang around the S'pile crowd very much. Y'know, flat ribbon cable or 2"-diameter wires on little trestles, wood blocks on top of the electronics, that kind of thing.
I have no idea why my fave electrostats are the ancient ESL57's - the poor things certainly have enough issues, with very limited SPL, and pretty bad side-to-side venetian-blind effects. But other electrostats can sound kind of weird, ranging from edgy to muted and rolled-off. These aren't easy speakers to get right. If I had to buy new I guess I'd check out Stax or those Dutch electrostats. These days, maybe you have to go DIY to get traditional electrostat sound. It wouldn't surprise me.
kevinh said:
I've heard them locally at a Denver audiophile's house and a truly gigantic system at the last RMAF. Each speaker must have had a surface area the size of an SUV - it was huge partially cylindrical array, each side powered with a giant stack of Krells. I was told the system cost more than a million bucks.
Sonically? Ehhh, only just OK. Timbres sounded kind of pale, diminished and flattened out - and dynamics, despite the immense size, were just so-so, typical dynamic-speaker fare. Symphonic music just didn't have the sparkle and immediacy I expected, given the tremendous resources thrown at this system. But in all honesty, I don't think it's at all fair to assess Sound Labs based on the crazy, over-the-top RMAF demo in a huge hotel ballroom, big enough to park a semi-truck in.
(I don't think any kind of audiophile speaker works in theater-size spaces - that's what prosound systems are for.)
As for the Sound Labs at a local audiophile's house, I dunno. I didn't hear the sparkle I expected - I was a bit surprised, actually. By "sparkle" I don't mean HF extension, more a quality of liveliness and expressiveness, those little quirks of performance that makes music so enjoyable. I'd have to characterize it as a very "audiophile" kind of sound - take that for what you will.
But again, limited sample size. Just because they sounded funky doesn't mean they couldn't be terrific if used in the right way, in the right environment. But I don't know what that right environment would be, since I don't hang around the S'pile crowd very much. Y'know, flat ribbon cable or 2"-diameter wires on little trestles, wood blocks on top of the electronics, that kind of thing.
I have no idea why my fave electrostats are the ancient ESL57's - the poor things certainly have enough issues, with very limited SPL, and pretty bad side-to-side venetian-blind effects. But other electrostats can sound kind of weird, ranging from edgy to muted and rolled-off. These aren't easy speakers to get right. If I had to buy new I guess I'd check out Stax or those Dutch electrostats. These days, maybe you have to go DIY to get traditional electrostat sound. It wouldn't surprise me.
Lynn Olson said:
Which begs the question: What do we want from Hi-Fi?
Most of us who haunt forums like this profess to want a sound as close to the "real thing" as possible. Getting close to the real thing is a true emotional thrill. Tingles up and down the spine.
But what is wrong with a Cinerama-Technicolor approach to audio? When I go to the cinema I do not expect to see a perfect imitation of real life. That's not what I'm paying for. Give me bigger, better, more colorful than real life!
One of the most beautiful things I ever saw was a 70mm print of David Lean's Ryan's Daughter. More real than real. Every rock, every plant, every moss covered stone wall and dripping wet leather fishing boat was so real that you could touch it - and so beautiful that you ached to. Much, much more vivid than life. It was art.
I've had some audio experiences like that too.
Joe public doesn't care if his audio system sounds real. He just wants it to sound cool. The same with boom-boom boy in his rolling sound palace. The emotional thrill for them is not in accuracy. Nor is it for fans at a rock concert.
Most of us following this thread know how thrilling accuracy can be, the cheap tricks don't turn us on. We crave an accurate reproduction. But getting beyond that, is a little melodrama amiss? Is a touch of hyper-realism out of place? Or is a more accurate portrayal of reality enough?
I just want to do something creative, learn, experiment, and have pleasing sound that gives good clue to music as I have experienced it. I have listened to a lot non amplified music but my bulk is with amplified live and studio work. I see DIY audio as comparatively elevated amongst popular enough hobby genres. And gets you to meet good cultivated people too. All in all positive. Illusions of recreating reality are not my thing. This is for when paying grand sums as a Hi-End client and must have justification.
Lynn Olson said:
I've quoted the two points that we agree on.
My floor bounce piece of carpetting is about 3" thick (I use a futon under a throw rug), because you are quite correct, it takes a lot to get 20 dB reduction.
Its too bad that you never gave my speakers a chance (intollerable electronics) because I think that they would change lot of what you say here. I simply don't belive that someone can evaluate a good sound system in a few minutes using unfamilair sources. This was what you and most everyone else heard at RMAF. Thats why I belive that type of venue is more misleading than useful. A system has to "grab" you at a show like that, and anything that "grabs" you is IMO not a good thing. It takes a lot longer to appreciate a really good system than it does to be attracted by a partcicular feature of a mediocre one.
I'm off to BKK so I don't think that I will get a chance to come back to this thread. Take care.
Lynn Olson said:
I think it can be said that the more speakers/channels involved, the more important a more narrow directivity is.
Earl is coming from a HT focus, which uses more than two channels. Indeed, for some of the multichannel schemes to work as they are supposed to, controlled directivity is required.
As I read these different prospectives I keep finding my mind work back to what appears to be the biggest culprit; Recording quality.
I don't think it's a fault but a limitation. In the early 80's when I 1st started using one of the 1st DBX units I felt there was a very real tactile improvement to the dynamics. It really did try to compensate for the compression that had to take place in Vinyl in order to not create a groove too big for the needle. Many traditionalists find exotic means of approaching Turntables but has there been any change in width capacity of the groove itself? If not, it is all for not.
It just seems impossible to get even remotely close dynamics without the use of a medium/device that is able to effort to reproduce more adequate dynamics. I'm speaking of a quality reel to reel. Everything else appears to be nothing more than a device designed to compress.
There also seems to be an even bigger issue, at least in my mind; that is sound propagation of played instruments (live) verses reproduced sound. Why does live music sound so much deeper? Is this an outcome of compression? Or, is this how the sound is propagated in 3 dimensions?
What has been done, with regard to research, on sound propagation of individual instruments? It would seem that if there was a better handle on how a violin scatters the sound, transducers could be better designed to mimic those same types of dispersion patterns.
Lastly, we stick a $1 CD into our $20k systems, am I the only one that sees the mismatch? Isn’t this the same as Garbage in, Garbage out?
I don't think it's a fault but a limitation. In the early 80's when I 1st started using one of the 1st DBX units I felt there was a very real tactile improvement to the dynamics. It really did try to compensate for the compression that had to take place in Vinyl in order to not create a groove too big for the needle. Many traditionalists find exotic means of approaching Turntables but has there been any change in width capacity of the groove itself? If not, it is all for not.
It just seems impossible to get even remotely close dynamics without the use of a medium/device that is able to effort to reproduce more adequate dynamics. I'm speaking of a quality reel to reel. Everything else appears to be nothing more than a device designed to compress.
There also seems to be an even bigger issue, at least in my mind; that is sound propagation of played instruments (live) verses reproduced sound. Why does live music sound so much deeper? Is this an outcome of compression? Or, is this how the sound is propagated in 3 dimensions?
What has been done, with regard to research, on sound propagation of individual instruments? It would seem that if there was a better handle on how a violin scatters the sound, transducers could be better designed to mimic those same types of dispersion patterns.
Lastly, we stick a $1 CD into our $20k systems, am I the only one that sees the mismatch? Isn’t this the same as Garbage in, Garbage out?
Lynn Olson said:
We certainly have quite a bit in common in our approaches.
I see the Revel's as the pinnacle of the Toole School of voicing, and somehow I find they don't provide the thrill or connection of live or really good hifi. The analogy of designed for mass tastes is perceptive.
As for real vs pleasing, what's the point of spending our precious time not enjoying music as well as we could, to conform to a populist opinion of accuracy, especially when considering that this benchmark is flawed (see the "Flat" thread I started for just one example). Stereo is so far from an acoustic hologram, that the implication of accuracy only makes sense if we optimize design targets in the same way an audio compression algorithm views data streams. In the context of stereophony: what can we hear? What can't we? What data is needed, or discardable when we make our invariable system trade-offs? No one has really looked at this with any over-arching holistic. The spot-lights are shone brightly into corners as minute details are polished (difference limens for response, distortion, etc), but the larger hypothesis is never challenged or studied for improvement. Stereo crosstalk alone is an abomination that resets the playing field, vs live. I rejected the “Absolute Sound” philosophy in the very early 80s after a brief stint as a subscriber. The paradigm doesn’t hold water. Absolute to what? The actual “event” (whatever that is, I wasn't there)? Or our recollection of the event even if we were? Its important to loosen the restrictions and go more from the gut. Science is the tool, not the end goal.
LP imaging: I have a totally unproven theory that LP’s inherent poorer mechanical L-R crosstalk helps mitigate stereo’s inherent poor acoustic crosstalk, as one possible explanation for the superior imaging off vinyl. Looking at holography algorithms, they inject phase and frequency response manipulated crosstalk. It would be an interesting experiment, to characterize LP crosstalk and see if there is anything to this.
In the “agree to disagree” camp, tight phase tracking has never been my cup of tea. Perhaps it’s just been due to the limits of my experiences, but I find they often sound lifeless. Technically, they also result in a nice large hole in the room contribution, in a way that real instruments and acoustics sources just don’t. I’ve been favouring uncorrelated low Q thirds for some time. If done well, there’s no phasiness, and the ruse is just more believable to me.
Floor reflection: I know this well of course, having danced with it for many years. I now use a small spreadsheet I designed, to calculate the exact placement in the impulse response of the floor reflection with the measurement set-up parameters chosen. Helps quickly optimize set up and windowing when measuring designs. I also spent many months trying to eradicate the floor from measurement, using an all out attack of Roxul, air gap, and hard fiber board, but it never reduced it to the point where the measurement window could be usefully extended. Interestingly enough was the discovery of competing forces: thickening the absorption and air gap in order to improve lower frequency attenuation (the purpose of the exercise after all), resulted in a shallow “bounce” angle off the absorber. The absorption coefficient of these lossy materials is specified normal to the plane surface. The paradox is that, as the material thickens to improve low end absorption, the angle of incidence shallows, and absorption decreases in the mid band to the point that ripples reappear at 1khz and up! No win scenario.
To clarify the point I was trying to make with the floor reflection comment, vertical reflections don’t only impact tonality, they can also distort image size, under certain conditions. I’d have to re-read the paper to quantify the impact on “downside” with floor delays, if any.
...especially in recording classical genre.DDF said:
Perhaps not totally unproven. I've heard it said that a CD copied from an (analog) master tape sounds closer to the tape than a record recorded from the same tape.
The theory is that digital recording has too much channel separation. Too much of a good thing turns out not to be compatible with our hearing perception, it is argued. The analog tape, on the other hand, has channel crosstalk that is recorded in the CD version, as opposed to a digital recording chain to CD, which perserves separation.
Richard Brice promotes this theory in a Wireless World article way back in the 80s or 90s. Don't have that info, but he has a web site:
http://richardbrice.net/franci.htm
He used to market a product called Francinstien, of all things, but is no longer commercially available.
He gave me a schematic of a simple passive circuit to try out the effect, but I have not yet incorporated it in my preamp CD input. I have attached the schematic for anyone interested in trying it.
The commercial version added buffers, I believe.
Attachments
I suspect the same - see
this post
I guess we all reinvent the wheel here, I for once wasn' t aware of Richard Brice.
BTW that kind of circuit is ubiquitous in the headphone department, headwize.com has a lot of crossfeed simulators and auralizers to that effect.
I am also in the camp of those who believe that you do need lateral reflections and not just reverb. I don't think that everything is on the recording, and if you take the playback room completely out of the equation, except for generalized reverb, you end up with headphone sound with reverb. I do believe that lateral reflections, as long as they are sufficiently delayed, are necessary, just as a certain amount of floor reflections, to make it sound real. I think ASW "generated" by the actual playback room much more of a real thing than the panning, phase jumbling or other tricks used during mixing and mastering.
Of course it is also a philosophical question - "are you there?" vs. "are they here", a question of application - studio monitors should really just play what's in the feed - and of recorded material - if ambiance is on the recording, you don't need or want the playback room to add to it; if it's a studio recording with just some panning and reverb added, I think you definitely want to add a real room's effects.
In any case, highly directional speakers, or beaming fullrangers, always give me a very detailed impression, but also a very unreal one: as if listening through a narrow tunnel, with the sound coming out of a distant window.
But I haven't heard Earl's speakers set up the way he recommends, he might have solved this issue.
this post
I guess we all reinvent the wheel here, I for once wasn' t aware of Richard Brice.
BTW that kind of circuit is ubiquitous in the headphone department, headwize.com has a lot of crossfeed simulators and auralizers to that effect.
I am also in the camp of those who believe that you do need lateral reflections and not just reverb. I don't think that everything is on the recording, and if you take the playback room completely out of the equation, except for generalized reverb, you end up with headphone sound with reverb. I do believe that lateral reflections, as long as they are sufficiently delayed, are necessary, just as a certain amount of floor reflections, to make it sound real. I think ASW "generated" by the actual playback room much more of a real thing than the panning, phase jumbling or other tricks used during mixing and mastering.
Of course it is also a philosophical question - "are you there?" vs. "are they here", a question of application - studio monitors should really just play what's in the feed - and of recorded material - if ambiance is on the recording, you don't need or want the playback room to add to it; if it's a studio recording with just some panning and reverb added, I think you definitely want to add a real room's effects.
In any case, highly directional speakers, or beaming fullrangers, always give me a very detailed impression, but also a very unreal one: as if listening through a narrow tunnel, with the sound coming out of a distant window.
But I haven't heard Earl's speakers set up the way he recommends, he might have solved this issue.
The channel separation of digital systems is 'unreal'. Think about it: Is it possible to hear something with your right ear while the level on the left ear is 96dB down? No , of course not.
I have one of these psycho-acoustic processing boxes, an SPL Tube Vitalizer The output stage is designed to reduce the channel separation to about 55dB while at the same time adding a tiny bit of stereo expansion. The net result is that the soundstage is wider, while at the same time the music is 'closer together' (sounds like a band and not a bunch of separate instruments).
I know that the usage of such a device is nothing short of heresy, but I'm with Joe Meek on this one: If it sounds right (for me) it is right (for me).
Back on topic:
For the construciotn of the baffle, what about a real sandwich panel : two layers of birchply with 3-4cm of fine white sand in between.
I also came across some stuff they use for isolating engines in yachts. It is made of 8mm okoume ply - 6mm heavy rubber (12Kg/m2) - 8mm okoume ply. It can be found here: Kuiper Fineer (sorry it's only in Dutch)
I have one of these psycho-acoustic processing boxes, an SPL Tube Vitalizer The output stage is designed to reduce the channel separation to about 55dB while at the same time adding a tiny bit of stereo expansion. The net result is that the soundstage is wider, while at the same time the music is 'closer together' (sounds like a band and not a bunch of separate instruments).
I know that the usage of such a device is nothing short of heresy, but I'm with Joe Meek on this one: If it sounds right (for me) it is right (for me).
Back on topic:
For the construciotn of the baffle, what about a real sandwich panel : two layers of birchply with 3-4cm of fine white sand in between.
I also came across some stuff they use for isolating engines in yachts. It is made of 8mm okoume ply - 6mm heavy rubber (12Kg/m2) - 8mm okoume ply. It can be found here: Kuiper Fineer (sorry it's only in Dutch)
Hi
You sure can, but don't necessarily have to buy several houses on the American coast, Hong Kong or where ever to find out what room size or absorptive treatment fits best to wave guide or high dispersion speaker concepts.
There is CARA to simulate that with much lower investment – any decent headphone will allow you to get an idea about room interaction with speakers thanks to the convolution utility besides a lot of diagrams.
Listening to music can be a cosmic experience to us but the thrill to labour on something that makes this happen – DIY audio in our context – is what hooks me no less.
The "respectfully disagreement battle" between Linn and Edd for me has a lot to do with preferences to the perception of beeming to the event or get the event to your place, which already was touched somewhere else in that thread.
It also is kind of a highly philosophically battle that tells us about HOW we prefer to escape from reality into hyper reality.
----------------
designed for the highest level ...
Good point that we all are looking for!
But also very much dependent on what the recordings were made for – which puts in a term into the equation that can not be altered at all.
Another good point is to make as may recordings sound as "right" as possible – which puts in a term into the equation of personal taste and subjectivity along with what the crowd liked when recorded.
----------------
Earl, thanks for all the detailed information and the very much appreciated teaching you give. If that articles site at DIY audio mentioned by our Chief Moderator is gonna happen I hope we will see papers there from you.
Like Lynn with his very much appreciated magician hat I now put on my beloved pupils hat :
If I understood your explanation of the HOM issue right it always happens whenever there is a discontinuity in the WG or horn surface that makes the surface unperpendicular with respect to the waves front? If so, ANY real world loudspeaker surface would create HOM to some extent. One effect should be than that it is located to a certain point in space right at the horn surface !?
( BTW there is a highly respected speaker simulation program called AJHORN where its author claims that ALL speaker enclosures can be seen and modelled as a variant of horns.)
What exactly makes HOM different to pure diffraction effects virtually creating a new source point ?
I am not sure that I could catch the point why you say even the speaker itself produces HOM ?
Putting a flat diaphragm, piston like moving speaker right in the middle of an infinite line should create no HOM at all ( though not very practical for what we want ). Thus NOT the loudspeaker is creating HOM but the need to couple it in one way or another to our listening room ?
Last question: HOW can HOM be identified from FR, swept HD, CSD plots ?
This I ask in particular as I noticed a VERY big change in harmonics measurement when modifying a speaker with a phase plug replacing the dust cap.
Greetings
Michael
You sure can, but don't necessarily have to buy several houses on the American coast, Hong Kong or where ever to find out what room size or absorptive treatment fits best to wave guide or high dispersion speaker concepts.
There is CARA to simulate that with much lower investment – any decent headphone will allow you to get an idea about room interaction with speakers thanks to the convolution utility besides a lot of diagrams.
Listening to music can be a cosmic experience to us but the thrill to labour on something that makes this happen – DIY audio in our context – is what hooks me no less.
The "respectfully disagreement battle" between Linn and Edd for me has a lot to do with preferences to the perception of beeming to the event or get the event to your place, which already was touched somewhere else in that thread.
It also is kind of a highly philosophically battle that tells us about HOW we prefer to escape from reality into hyper reality.
----------------
designed for the highest level ...
Good point that we all are looking for!
But also very much dependent on what the recordings were made for – which puts in a term into the equation that can not be altered at all.
Another good point is to make as may recordings sound as "right" as possible – which puts in a term into the equation of personal taste and subjectivity along with what the crowd liked when recorded.
----------------
Earl, thanks for all the detailed information and the very much appreciated teaching you give. If that articles site at DIY audio mentioned by our Chief Moderator is gonna happen I hope we will see papers there from you.
Like Lynn with his very much appreciated magician hat I now put on my beloved pupils hat :
If I understood your explanation of the HOM issue right it always happens whenever there is a discontinuity in the WG or horn surface that makes the surface unperpendicular with respect to the waves front? If so, ANY real world loudspeaker surface would create HOM to some extent. One effect should be than that it is located to a certain point in space right at the horn surface !?
( BTW there is a highly respected speaker simulation program called AJHORN where its author claims that ALL speaker enclosures can be seen and modelled as a variant of horns.)
What exactly makes HOM different to pure diffraction effects virtually creating a new source point ?
I am not sure that I could catch the point why you say even the speaker itself produces HOM ?
Putting a flat diaphragm, piston like moving speaker right in the middle of an infinite line should create no HOM at all ( though not very practical for what we want ). Thus NOT the loudspeaker is creating HOM but the need to couple it in one way or another to our listening room ?
Last question: HOW can HOM be identified from FR, swept HD, CSD plots ?
This I ask in particular as I noticed a VERY big change in harmonics measurement when modifying a speaker with a phase plug replacing the dust cap.
Greetings
Michael