"What's with the nostalgia craze!? Those old designs were basically not very good."
Hello Earl
The lenses look good and subjectively can sound quite good with no side by side comparison.
Rob🙂
Hello Earl
The lenses look good and subjectively can sound quite good with no side by side comparison.
Rob🙂
Robh3606 said:
I wondered about this before, and i think one can easily come to the conclusion that gedlee tries to quantify a subjective experience by objective criteria and by this tries to teach you what should sound good for you. But i think this conclusion is wrong. It too obvious that one mans heaven is the others hell.
It rather seems to be, that he shows how a good reproduction of a signal - in a purely technical sense, in terms of less perceived distortion and diffraction and so on - can be achieved. That he prefers this sound in an aesthetical way does not mean that you can not prefer a different sound.
The aesthetic preference is not an argument for or against his or anyone elses approach to sound, because it is allways individually perceived.
I agree with this as far as 'taste' goes, but strongly disagree that it has anything to do with reproduction.MaVo said:
MaVo said:
All system design and implementation involves a certain amount of compromise, and in this compromise there could be a preference. This is one of the only areas where sound reproduction resembles an 'art form'.
Your preference for one compromise may be different than someone else, but overall your ears and brain will prefer the same quality of sound as everyone else on the planet. Unless, of course, you have been 'trained' by years of listening to low quality audio reproduction, you will prefer the highest quality of sound reproduction possible as this will closely represent what is natural to you and anyone else.
Robh3606 said:
Proving once again that we are such visually oriented animals that we tend to 'hear' what we 'see'. Since I find them quite ugly, I tended to subjectively dislike their 'sound' long before measurements proved why, so 'beauty' truly is in the eye (ear) of the beholder. 😉
GM
MartinQ said:
GM said:
Brain conditioning by visual and aural cultures leads to different aesthetic appeal. That is why every tech that has a history and a distinctive sonic signature has its proponents. If a child is made to wear pink tinted eyeglasses and grow up like that, you cant argue that the world ain't pink.
MaVo said:
The only reason why people think this is wrong is because they don't like being told what to do and that dislike trumps their desire to understand reality and arrive at the best sound system.
The fact of the matter is that there is a very high correlation between measurements and subjective impression. Your "obvious" conclusion is just plain wrong and has been shown to be so many times. Most of what Geddes is "trying to teach" you is very basic and well accepted in the audio industry (e.g. Toole's work from 20+ years ago).
MaVo said:
But people don't. When you put speakers in a room and have people compare them with stray variables controlled, they always prefer the same speakers. When you compare trained vs. untrained listeners, they prefer the same speakers (but trained listeners are more precise). When you compare the same speakers in different rooms, at different times, or in different locations around the world, the listeners prefer the same speakers. The speakers they prefer are (in summary) the ones that have smooth and flat or slightly downward tilted responses on and off axis. Over the years these things have all been studied. That isn't to say that we understand all of this, but that's never what Geddes is claiming; he makes it clear when he is unsure about a conclusion.
angeloitacare said:
This hypothesis was actually tested. We built Summas with TADs and B&C drivers - a 10:1 price difference. Both systems were optimize with different crossovers. We had 16 people audition them - blind, of course - and statistically there was no difference, marginally the B&C were prefered (but it was not statistically significant with only 16 people).
So could one actually go all the way down to a Radio Shack driver (if they made compression drivers) Maybe!! I've never tried.
I will say that I know that I could make a loudspeaker system using a $17 Chinese B&C copy work almost indistinguishable from the TADs. Thats pretty close to Radio Shack pricing. (I say almost because I haven't tried this and don't have the data, but based on my experience and driver tests, I would bet on the results of this test being a statistical wash.)
JLH said:
The size would have to grow to an enormous device to do what you want.
First to control directivity to 600 Hz would require a mouth that is about 30" across. Then to load down to this frequency - assuming the driver can go this low, which I doubt, would require a narrower angle, say 60°. Now the length of this device has just quadrupled from the one that I use. Good luck with making and using that. And what are you going to cross over to at 600 Hz that has a polar response of only 60°? A 27" woofer?
Narrower angles improve loading at LF and reduce the HOM, but cause massive growth in size as highlighted above. The reason that I use what I use is not a coincidence. Things simply get out of hand quickly taking the design in different directions without making major compromises in performance.
MaVo said:
You can believe what you want, but I think that your position is wrong.
How can you justify taking the position that something that is objectivly wrong can be subjectively correct if we are talking about "high fidelity reproduction". It is possible to have two different objective errors where one has to decide which will be the more audible, but it ludicrous to suggest that an obvious objective error is "OK" because "It sounds good to me". This is the nieve world of the audiophile that I refuse to live in.
intermediate shape
I am also interested in a waveguide shape, more advanced than classic tractrix, that would load a 1,4" or 2" compression driver as low as 600/700hz, below used with a 38" midbass horn. Since a oblate spheroid to load that low down would be too big, how about a intermediate shape, between tractrix , and oblate spheroid ? just with a wider mouth angle, or a combination with a sligtly narrower angle of the waveguide ?
Angelo
_____________________________
http://www.audiovoice-acoustics.com/forum/
http://www.flickr.com/photos/12312992@N07/page1/
I am also interested in a waveguide shape, more advanced than classic tractrix, that would load a 1,4" or 2" compression driver as low as 600/700hz, below used with a 38" midbass horn. Since a oblate spheroid to load that low down would be too big, how about a intermediate shape, between tractrix , and oblate spheroid ? just with a wider mouth angle, or a combination with a sligtly narrower angle of the waveguide ?
Angelo
_____________________________
http://www.audiovoice-acoustics.com/forum/
http://www.flickr.com/photos/12312992@N07/page1/
Re: intermediate shape
The OS waveguide is defined for any angle - see the equation. The narrower the angle the lower in frequency it will load. You can't have wide angle and low frequency loading in a waveguide any more than you can in any other device. Think of it as "flare rate" if you have too (although this is technically incorrect). The higher the flare rate the higher the "cutoff" (again a technical misnomer).
Your intermediate curve does not follow the OS contour. Of course sound will propagte down it, it will no matter how its shaped, but there will be more diffraction if its not OS.
angeloitacare said:
The OS waveguide is defined for any angle - see the equation. The narrower the angle the lower in frequency it will load. You can't have wide angle and low frequency loading in a waveguide any more than you can in any other device. Think of it as "flare rate" if you have too (although this is technically incorrect). The higher the flare rate the higher the "cutoff" (again a technical misnomer).
Your intermediate curve does not follow the OS contour. Of course sound will propagte down it, it will no matter how its shaped, but there will be more diffraction if its not OS.
Hi gedlee,
first i must say that i respect and agree with your aproach and my comment was not a criticism, but merely a try to construct a point of view which can accept all kinds of likes and dislikes, while still aiming at scientific progress. Your approach is the only way to be able to talk about speakers constructively, as you do it scientifically.
"How can you justify taking the position that something that is objectivly wrong can be subjectively correct...?"
>> I do not say that he is correct. Someone who is objectively wrong is wrong by all means. But when speaking about subjectivity, the term "correct", "wrong" or "right" (as in "this equation was solved in a correct way") has no meaning. If you say, that it is correct that someone likes the distortion of old tube amplifiers, it has no other meaning than that he likes the distortion of old tube amplifiers. The term "it is correct" simply drops out of the equation, if you talk about subjective experience. If you speak about subjective experience, terms like sincereness fit better. One can be sincere about liking old tube amplifiers or he can lie about it.
So i say that he isnt subjectively correct as one cannot be correct or wrong in a subjective sense. He just has a subjective experience, which stands beside the objective experience without touching it in any way. The difference is the one between knowing and feeling.
Imagine a person who loves the sound of his old radio much more than the sound of a highend speaker, simply because it evokes emotions in him due to kind memories of the past. This person would be able to agree that your approach is objectively the right one. But still, he would prefer his old radio - not in spite of its bad sound but because of its bad sound.
first i must say that i respect and agree with your aproach and my comment was not a criticism, but merely a try to construct a point of view which can accept all kinds of likes and dislikes, while still aiming at scientific progress. Your approach is the only way to be able to talk about speakers constructively, as you do it scientifically.
"How can you justify taking the position that something that is objectivly wrong can be subjectively correct...?"
>> I do not say that he is correct. Someone who is objectively wrong is wrong by all means. But when speaking about subjectivity, the term "correct", "wrong" or "right" (as in "this equation was solved in a correct way") has no meaning. If you say, that it is correct that someone likes the distortion of old tube amplifiers, it has no other meaning than that he likes the distortion of old tube amplifiers. The term "it is correct" simply drops out of the equation, if you talk about subjective experience. If you speak about subjective experience, terms like sincereness fit better. One can be sincere about liking old tube amplifiers or he can lie about it.
So i say that he isnt subjectively correct as one cannot be correct or wrong in a subjective sense. He just has a subjective experience, which stands beside the objective experience without touching it in any way. The difference is the one between knowing and feeling.
Imagine a person who loves the sound of his old radio much more than the sound of a highend speaker, simply because it evokes emotions in him due to kind memories of the past. This person would be able to agree that your approach is objectively the right one. But still, he would prefer his old radio - not in spite of its bad sound but because of its bad sound.
Is it possible to have a technical discussion directed back to waveguides....and move the objective/subjective reproduction discussion elsewhere?
MaVo said:
The problem is that you took the above phase out of context because you left off '...if we are talking about "high fidelity reproduction".' Because what you are talking about has nothing to do with fidelity and it is absolutely correct if the "subjective opinion" is obtained with no connection to "accuracy". Then there is no right or wrong, but as such it is pointless to discuss anything at all.
The only way that these posts have any meaning beyond the mundane "well I like ...", "and I like...", and "I don't like ..." is to frame the context around "accurate reproduction" as the goal. When that framework is in place then rational and meaningfull discussions of how to achieve said accuracy can take place.
I never discuss the purely subjective aspects and I have always made this perfectly clear. So its kind of like beating a dead horse to post comments about what I have always claimed to be the case - that I direct my designs purely by science, verified - in the end - by listening, with the sole intent to achieve acurate reproduction.
Re: Re: intermediate shape
Who has published the best tool for calculating an OS waveguide? I have a spreadsheet which I use, and I've published here. But it's fairly crude. For example, it doesn't take into account the entrance angle (it assumes the angle at the throat is zero degrees.)
Here's mine
gedlee said:
Who has published the best tool for calculating an OS waveguide? I have a spreadsheet which I use, and I've published here. But it's fairly crude. For example, it doesn't take into account the entrance angle (it assumes the angle at the throat is zero degrees.)
Here's mine
gedlee said:
Dr, Geddes,
30" horns are not a problem for me. I've built larger horns than that.
Just to clarify, when you say “polar response of 60 degrees at 600Hz”, how far down in response (i.e. -6dB?) at 60 degrees are you referring to?
I fully understand why such a waveguide that we are discussing here is completely useless for the general market. However, as an extreme DIY effort it interests me a great deal. Thank you for addressing my first post on this subject.
Rgs, JLH
JLH said:
As a general rule, a 60° waveguide would be -6dB at 60° (+-30°). If the waveguide mouth is too small, this will not hold true at the lower frequencies. It will narrow and then widen as the frequency goes down.
This is exactly where the problem is. Lets say you require a match of the polar responses at the crossover (to me this is essential, an absolute requirement that tends to drive everything else). If you make the mouth too small then you need an even bigger driver below to match this pattern. If you go lower in frequency to get back to the original coverage pattern then you don't have CD anymore as the pattern is wide, narrows then widens again. So you have to go up in frequency to get to the point where the pattern stabalizes to its design intent.
In my designs, as the mouth gets smaller I take the crossover point higher as this is required to get to the right pattern. But this is OK since the woofer required becomes smaller to match the HF pattern. Thats how the designs can stay fairly constant as they get smaller. The MAX_SPL drops off, but the coverage pattern stays pretty constant through crossover. The lower frequency point of the coverage control is moving up and this is not desirable, but unavoidable. These are the two compromises with size.
Re: Re: Re: intermediate shape
John
Is "Google docs" something that I want to do? I hate signing up for everyone of the latest "web services".
Josh Knectel worked out the equations for doing the offset. He posted those at some point.
Patrick Bateman said:
John
Is "Google docs" something that I want to do? I hate signing up for everyone of the latest "web services".
Josh Knectel worked out the equations for doing the offset. He posted those at some point.
It's single sign on, so if you use any of Google's products, using Google docs doesn't require an additional login. Personally I couldn't live without gmail; it's like a giant filing cabinet with the best search functionality I've ever seen. Another nice thing about Google docs is that it's cross-platform. This is nice since I use a Macbook, an OpenSolaris box and a Windows laptop.