Yeah I can get that with two cones. Why is that the case with a cone and a ribbon?
Besides in this case it hardly makes a difference since the planar is only 1/2 inch wide, so we are talking about adding 1/4 of an inch. I see it as moot.
Regardless of your need to split hairs, I’m still producing a speaker that pretty much doesn’t split either range.
When you have two sources that are within one quarter wavelength of each other, they will largely act as a single source. As the distance grows, an interference pattern emerges. When the pathlength difference between the two sources is one half wavelength, you'll get deep narrow dips in the frequency response. This is because the two sources are 180 degrees out of phase.
With a crossover frequency of 2000Hz, you'd need to get the tweeter and the midrange within about 5cm, give or take a centimeter.
If you can't get the drivers that close, you have two options:
1) live with really terrible polar response right where it sounds the worst (the midrange)
2) drop the xover point
Keele went with option two in the CBT36. In JBL's CBT, they mounted the tweeters coaxially.
JBL, are designed to be listed to in the Farfield, not the near field.
Please give me a graph that shows what you are describing, and explain what you are describing sounds like, and where in the sound field one is likely to hear the problem.
I fail to see how polar response directivity is an issue in a nearfield line array where the speakers are directed at the listening spot, and one really doesn’t care about the axis response of the speakers.
The only way you can have the line of speakers closer than 1.9 inches is to use a coax or a singe speaker. We already discussed the disadvantages of running a tweeter line right over top of the center of the midranges. Most speakers do exactly what you describe as horrible, and no one complains. My last line array did it, and it sounds spectacular.
Perhaps you have trained your brain to hear what the Haas Effect has eliminated. This is possible.
But it is possible that I am totally confused.
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In a small listening room one receives more reflected sound than direct sound, hence the power response, which is a function of the polar response, is critical. Our studies on the perception of reflections are showing a big issue with reflections and perception - a reflections response depends on the polar response. The axial response is important, but no more so than the power response.
Only at the crossover, and not if you are using a 24 db L-R active crossover. Besides, I can flip the polarity in my crossovers with a switch if think they are 180 out of phase.
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To have negligible reverberation field one would have to be so far into the direct field (you use "near field" which is not the correct term) that you would have to be only a foot or two away from the speakers. This, of course, depends on the room, but in virtually any small room you would have to be extremely close to the speaker to not get any significant reverberation. The Hass effect does not have anything to do with coloration and is really over used in audio as it doesn't really apply to "sound quality".
Interesting.
In the car audio world, during the last 10-20 years people have gone nuts with DSP. A typical car audio system in 2018 has a midrange and tweeter that are as much as 1-2 feet apart, and they use DSP to hammer everything into shape.
The end result is an incredible soundstage; I'd argue that a typical car audio system in 2018 images better than a home system. (Because the DSP allows you to fine tune everything to the nth degree.)
But the tonality always seems "off" to me.
My home system is the opposite of this; the imaging isn't pinpoint, but tonally, it's really excellent.
So perhaps the DSP in the car systems, used to optimize the system for a single sweet spot, is screwing up the reflected energy and polluting the overall perception of the frequency balance (aka "tonality.")
No need to argue with us on the Internet, build it and find out
Keep in mind, even Jim Griffin, author of the Linus line array paper, is using no tweeters in his line.
A lot of misunderstand here. Most of the sound in a living room is reflected energy. Thus the directivity of the speaker is crucial.
The Haas effect has nothing to do with us not hearing comb filtering. The precedence effect is only related to use not hearing two separate signals as in a echo. Comb filtering and reflections has a great effect on clarity, intelligibility, localization and tonality.
The Haas effect has nothing to do with us not hearing comb filtering. The precedence effect is only related to use not hearing two separate signals as in a echo. Comb filtering and reflections has a great effect on clarity, intelligibility, localization and tonality.
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One of the interesting things in Lidia and my study is that we get almost completely opposite results depending on the signal used. If one uses noise then image is not affected at all but the coloration is severe. If one uses impulse then the image is affected but there is little coloration.
My speakers image great and have great tonality. What's not to like!
My speakers image great and have great tonality. What's not to like!
That's correct. It has no relation to sound quality in a living room at all. One of many myths out there.
No need to argue with us on the Internet, build it and find out
But actually, I did just that, back in 2007. And I could not hear what you say you hear. I think its like the Clarke amplifier challenge. People claim that amplifiers are different, but if they are not clipping, and they are equalized for power, no one can hear the difference.
So you say. Like all the measurements that you can see but you cannot hear. Like comb filter distortion, where if you move upand down with pink noise you can hear it, but if you sit still with program content, you cannot.
It all just discussion.
Oops.
Another myth is that phase issues (lobing and combing) are audible avoided when drivers are spaced closer than 1/4 wavelength. But that's probably more controversial.
Well studied and proved.
So you say. But Dr. Jim Griffin has recanted on that. He says that with specialized program content that is designed to highlight it, you can hear it----if--- you move up and down while listening. But if you sit still listening to a varied program content, you cannot . And horizontal combing is even more difficult to hear.
Well studied and proved.
And without sources to show your well studied and proved point of view.
Again.... can you hear it, or can it just be measured.
I respond to proof. I don’t do well with authoritative viewpoints with people I never heard of using anonymous internet names.
If it's all just words and you don't believe any of it then why waste your time here?
But you quote the singular perceptions of someone that I have never heard of - that's not proof. Proof is when you do blind studies, like we do, and publish them in refereed Journals, like we have.
So show me. Yes I know that you are very smart, write books I cannot understand, and have a PhD in Acoustics.
But can one hear it with program material, not pink noise and specially selected music designed to show what you want?
I have violated much of what you describe as the LAW, but I cannot hear it, and people who listen to program material---like Pictures At An Exhibition, for example---say that the Line Array speakers I designed and built using Jim Griffin’s Line Array white paper, are the most realistic they every heard. They have all said it was like being in the concert hall when they closed their eyes.
I waste my time here for specific information that I cannot find on the internet, like your comments about putting a line of ribbons on top of the mids.
But even there, the person who was the most useful was LOWMASS who actually did it and told me what it sounded like to him.
And you respond with more authoritative stuff. But I’ve been here a long time. You do not have the end all answer. I have watched people with advanced degrees in electrical engineering argue with you---ON YOUR LEVEL. And you don’t always come out smelling like a rose. Sometimes you appear to win; sometimes its a draw; sometimes you lose. You don’t even go the PE’s Techtalk anymore for that very reason.
For you to argue with me is an easy mark. I have no idea whether what all you say is true, whether some of it is true, or whether some of it is just your viewpoint. And you can retreat to what is for me mathematical goble-de-gook, and I can say nothing.
For me, the comments by Lowmass are what counts.
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