The importance of keeping the sound radiating from the speakers intact (linear), although helpful if the level is reduced gradually off axis to limit the impact of the reflected sound.
Well, I guess you are in good company. Paul Klipsch explained all of this in one of his white papers at least 4 decades ago.
They had a series called the Dope from Hope that were meant to educate dealers and others. The collection is available over at the Klipsch forum.
I don't think this is entirely correct. FWIW, I happen to enjoy both "dry" recordings as well as "live" recording just the same in a fairly lively room. Clearly, the influence of the reflections from the drivers are minimized enough to make both scenarios work well. So, if the loudspeakers directivity is sufficient, the room should not matter.
all this about waveguide is sure true, but only at high frequencies.
Your wavguide wont control bass where your room, na matter what speaker, as as much to say as your speaker so to speak.
Its only after installing huge bass traps in my room that I have had punchy, tight and non boomy bass.
It is essential in these discussions to recognize that the physics and perception in the lower frequencies is completely different than it is at higher frequencies. On cannot make generalizations about acoustical design that covers both regimes. We cannot detect reflections at low frequencies in a small room they happen before the ear even has time to process the pitch. So what one wants in a speaker is certainly not going to be the same at low and high frequencies. In this thread I have commented mostly on the higher frequency aspects, not the lower frequency ones and so the fact that waveguides are not effective down at lower frequencies is simply not a valid issue. It does not matter. Now we might argue about what we mean by "low" and "high" frequencies, where the transition occurs, what happens in the transition region, etc., but one cannot argue that the 'low' and "high" frequency requirements are the same.
All low frequency signals are not tones with (intentional) pitch; pitch detection time is partly unsuitable & powerless argument.
All sound pressure variations and properties are not sensed only by ears; hearing does not cover the whole perception.
All rooms are not small, all small space rooms are not acoustically small and LF directivity can be useful also in small rooms.
All sound pressure variations and properties are not sensed only by ears; hearing does not cover the whole perception.
All rooms are not small, all small space rooms are not acoustically small and LF directivity can be useful also in small rooms.
I get the impression that a lot of this is 'orders of importance' rather than being 'absolute'. A lot of the time when we discuss things here on DIYA things come across as being absolute, simply because we are passionate about the direction we go in and things get lost that would otherwise remain clear during proper relaxed (read not just during a presentation) conversation.
Many is the time when someone will make a statement with a lot of assumed knowledge going along with it, but people, nevertheless, choose to talk about the unimportant assumptions, rather than focus on the true meaning behind what was said.
No doubt all aspects of the way that we, as human beings, perceive sound are important towards truly recreating a 100% authentic copy of the live event (and lets ignore the debate about whether or not that is ultimately the true goal or not for the moment). But whatever your end goals are everything is a compromise.
Even with all of that, I don't think it really changes anything of actual significance with that the things that you should be focusing on to arrive at good sound. I certainly don't see anything intrinsically wrong with the approach that Earl takes towards good sound and it has been the only approach that I've tried (and perhaps not the degree that Earl has though) that has actually made things significantly better, rather than just different.
I am sure that having good directivity down much lower in frequency than Earl goes would be of some benefit. Earl isn't saying that it is completely pointless, just that it is impractical in most terms and if one were to use a numerical scale of 'satisfaction achieved' via whatever method, you'd probably get 90-95% (and someone don't try and pick apart my numerical scale, I've used it by way of example) of the way there, so to speak, by not having directivity down low.
It's sort of like, we can easily get better bass reproduction by adding in multiple subs (without losing any efficiency), so we do that. And we can easily improve the top end of the spectrum by using the biggest wave guide that is visually/physically acceptable for a given room. What's left between isn't easily addressed, but as it wouldn't make a whole lot of difference to the enjoyment scale we say we can ignore it. This isn't to say that it isn't important, it is, but it isn't worth fussing too much over once what you can do right in that area is done right.
It's the same with room treatment. It isn't to say that it cannot be helpful. I am sure that it is in a number of circumstances, but it has to be done right if it's to be of any benefit, otherwise you're making things different rather than better. In other words, you'd be better off not using room treatment (unless it's obvious that the room needs something somewhere) and going with a set up that actually works with the room rather than having the room work against it.
Many is the time when someone will make a statement with a lot of assumed knowledge going along with it, but people, nevertheless, choose to talk about the unimportant assumptions, rather than focus on the true meaning behind what was said.
No doubt all aspects of the way that we, as human beings, perceive sound are important towards truly recreating a 100% authentic copy of the live event (and lets ignore the debate about whether or not that is ultimately the true goal or not for the moment). But whatever your end goals are everything is a compromise.
Even with all of that, I don't think it really changes anything of actual significance with that the things that you should be focusing on to arrive at good sound. I certainly don't see anything intrinsically wrong with the approach that Earl takes towards good sound and it has been the only approach that I've tried (and perhaps not the degree that Earl has though) that has actually made things significantly better, rather than just different.
I am sure that having good directivity down much lower in frequency than Earl goes would be of some benefit. Earl isn't saying that it is completely pointless, just that it is impractical in most terms and if one were to use a numerical scale of 'satisfaction achieved' via whatever method, you'd probably get 90-95% (and someone don't try and pick apart my numerical scale, I've used it by way of example) of the way there, so to speak, by not having directivity down low.
It's sort of like, we can easily get better bass reproduction by adding in multiple subs (without losing any efficiency), so we do that. And we can easily improve the top end of the spectrum by using the biggest wave guide that is visually/physically acceptable for a given room. What's left between isn't easily addressed, but as it wouldn't make a whole lot of difference to the enjoyment scale we say we can ignore it. This isn't to say that it isn't important, it is, but it isn't worth fussing too much over once what you can do right in that area is done right.
It's the same with room treatment. It isn't to say that it cannot be helpful. I am sure that it is in a number of circumstances, but it has to be done right if it's to be of any benefit, otherwise you're making things different rather than better. In other words, you'd be better off not using room treatment (unless it's obvious that the room needs something somewhere) and going with a set up that actually works with the room rather than having the room work against it.
Why don't we change the Thread Title to:
is there any good reason for having crossovers in the frequency range 1kHz to 4kHz?
The arguments against this range seem to be many.
What about pushing the crossover frequencies OUTSIDE 800Hz to 5kHz?
is there any good reason for having crossovers in the frequency range 1kHz to 4kHz?
The arguments against this range seem to be many.
What about pushing the crossover frequencies OUTSIDE 800Hz to 5kHz?
I think that is in fact what Earl is saying. Further, he's trying to convey the point that the wavelengths being what they are @ LF (undefined hz. ... that's OK) are basically uncontrollable and another approach (multi sub) is a good (perhaps only) work around for dealing with room modes at those frequencies.
Diplomacy and truth don't mix 🙂
I don't think that's what Earl is saying because one has to read these things with a degree of engineering common sense. Things don't just vanish or 'drop off' like a cliff, these things tend to diminish. In fact I have seen Earl say a number of times that going bigger, with regards to the wave guides, would only be a good thing, it's just not practical, nor is it that beneficial. You always have to draw the line somewhere.
Wavelengths and such as what determine if your room is small at a given frequency are obviously variable to quite a large degree. A 100Hz wave has a wavelength of 3.4 meters, this is also roughly equal the smallest dimension of my room. Does this mean that roughly below this is considered small and roughly above this is considered large? Again this will be something that changes gradually as frequency changes, kind of like how the baffle step transition occurs mostly over a couple of octaves. Maybe my room stops being small at around 100Hz, but for it to be fully 'large' we need to get to something like 500Hz, so for all intents and purposes, it is small for bass frequencies.
Wavelengths and such as what determine if your room is small at a given frequency are obviously variable to quite a large degree. A 100Hz wave has a wavelength of 3.4 meters, this is also roughly equal the smallest dimension of my room. Does this mean that roughly below this is considered small and roughly above this is considered large? Again this will be something that changes gradually as frequency changes, kind of like how the baffle step transition occurs mostly over a couple of octaves. Maybe my room stops being small at around 100Hz, but for it to be fully 'large' we need to get to something like 500Hz, so for all intents and purposes, it is small for bass frequencies.
My point is that it is not only; not always possible, needed or necessarily the best approach. Repeating single approach by picking suitable arguments and conditions while understating others sounds mainly commercial.
I agree but that is why one has to read between the lines. I said what I think ultimate system that follows that philosophy should look like. I haven't seen a system like that because it would need a lot of engineering and a lot of money. The ones that can doo the engineering don't want to invest that amount of money and the guys with money rarely have knowledge that is needed to do such a thing.
Closest thing I saw is OceanWay HR3 and Romys Macondo with xover frequencies at 95Hz / 600Hz /1KHz / 12.5KHz.
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Saying it differently: ares ESL or CD driver the only way to do it as wideband paper cone have to much problem for a detailed sound ?
All the tibbons planar even big seems not very good below 2 k...maybe some Maggies ?
e.g Neo 8 above 3.5k do not match, nore tpl 150 seems realy work below 2k...
mybe B&G rd75...this time this the Waf...
e.g Neo 8 above 3.5k do not match, nore tpl 150 seems realy work below 2k...
mybe B&G rd75...this time this the Waf...
The Griesinger papers are very interesting indeed, but talk mostly about sound localization and "engagement" in a reverberant field in the real world (concert halls). Griesinger concludes that "..the ability to localize sound in the presence of reverberation increased dramatically at frequencies above 700Hz. Localization in a hall is almost exclusively perceived through harmonics of tones, not through the fundamentals." and applies this to optimize halls by avoiding phase-scrambling early reflections and keeping a high D/R ratio for frequencies > 700Hz while actually increasing reverberant field below.
But, as you yourself pointed out, stereo phantom imaging might be a "slightly" different matter:
IMHO, Griesinger also does not really imply that reflections < 700Hz are not important and can be ignored. Two relevant paragraphs on the importance of the reflections sum:
"Toole and Olive [5] studied the audibility of individual reflections in rooms, and in [6] Toole implies that if individual reflections are below the level of audibility with respect to the direct sound they can be ignored. This is clearly not the case. In small rooms individual reflections are almost always inaudible individually, but there are a great many of them, and their sum is highly audible."
"if the amplitude of the sum of all reflections in a 100ms window starting at the onset of a sound is at least 3dB less than the amplitude of the direct sound in that same window the brain is able to perceive the direct sound separately from the reverberation, and timbre and azimuth can be perceived."
So, while the importance of reflections above 700Hz is emphasized, one cannot carelessly ignore what happens below and a directional source could be still preferable, as it helps achieve a higher D/R ratio compared to an omni.
#1: you don't need to go active. You can use a hybrid approach (http://www.musicanddesign.com/HybridDesign.html)
#2: My original question explicitly excluded efficiency from the equation. That's because it is well known and controllable to a certain degree (not everyone is going for very high SPLs). Reading about Linkwitz of JohnK's dipole speakers, efficiency does not really stand out as a common complaint - quite on the contrary.
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