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Thread: Vertical alignment of speakers

  1. #16
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    To simplify the discussion letīs narrow our attention to the extended-woofer only.
    Above 150hz this woofer operates alone and itīs the transition between this extended-woofer and the midhorn at 850hz thatīs of interest

    Another extreme example would be the old 4355.
    The 12" midwoofer is mounted right beside the midhorn. The midwoofer is roughly 13" off center compared to the midhorn.
    Several people reported this baffle-layout messed up the dispersion and imaging characteristics of this speaker...

    Compared to the Everest the woofer is much more off center compared to the horn and the crossover is at 1200hz (4355) rather than at 850hz (67000). Both would have a negative influence I guess. But where about is the threshold of what is noticeable or not?

  2. #17
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by Dr.db View Post
    Another extreme example would be the old 4355.
    The 12" midwoofer is mounted right beside the midhorn. The midwoofer is roughly 13" off center compared to the midhorn.
    Several people reported this baffle-layout messed up the dispersion and imaging characteristics of this speaker...
    I don't think we need to consider the original 43XX series in this discussion, as GT and JBL have learned a lot since that era. Those speakers were big badass designs, but compared to modern designs, they are not the last word in high fidelity.

    Quote Originally Posted by Dr.db View Post
    Compared to the Everest the woofer is much more off center compared to the horn and the crossover is at 1200hz (4355) rather than at 850hz (67000). Both would have a negative influence I guess. But where about is the threshold of what is noticeable or not?
    As to the degree of a compromise for the DD66000/DD67000, I imagine only GT could really answer that question. It would be great if he were to respond, but I don't think he visits this site often these days.


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  3. #18
    Senior Member Ian Mackenzie's Avatar
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    Part of the issue is people’s brains visualise via the optic nerve and that influences the perception of localisation.

    They listen with their ��.

    The Everest woofers are angled slightly outward. Maybe that has an impact. Maybe it doesn’t. Something for Olaf to ponder over.

  4. #19
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by Ian Mackenzie View Post
    Part of the issue is people’s brains visualise via the optic nerve and that influences the perception of localisation.

    They listen with their ��.
    I think this plays a much larger role than most of us care to admit.

    I always listened to my Everests with their grilles on, so the imaging was pretty good.


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  5. #20
    Senior Member Ian Mackenzie's Avatar
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    I was listening to a live Jazz quartet last night at a local venue. Only the vocals and the Hammond organ were amplified and as you might expect was the only thing coming from the centre.

    There was no point source.

    The enjoyment was the tone of the sax, the snap of the drums, the fine metallic overtones of the cymbals.

    Getting a loudspeaker to do all of that well is the priority.

    There are plenty of loudspeakers that image well but they don’t do anything else well. That might be what an audiophile craves for but what they are listening for is a lot of tiny unrealistic detail because the loudspeaker can’t do anything else.

    But where’s the tone, the realism at almost live levels and the micro dynamics that help a listener visualise the sound of individual musical instruments?
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  6. #21
    Senior Member jmpsmash's Avatar
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    Post

    Last year I was visiting a high school open house with my prospective son. they had a ~20 person jazz band playing outdoor in their main yard. I couldn't help but stood there and listened for 20 mins. Wondering about the same thing. There are so much details that comes out with natural timbre and so much texture from each instrument that paints a uniform acoustic image.

    I guess that's why we still go to concerts.

    having said that, compression horn seem to do much better than dome tweeters in terms of dynamics and details. But seems to be a bit to aggressive sometimes and spoils the natural part of it.

  7. #22
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    Quote Originally Posted by Ian Mackenzie View Post
    I was listening to a live Jazz quartet last night at a local venue. Only the vocals and the Hammond organ were amplified and as you might expect was the only thing coming from the centre.

    There was no point source.

    The enjoyment was the tone of the sax, the snap of the drums, the fine metallic overtones of the cymbals.

    Getting a loudspeaker to do all of that well is the priority.

    There are plenty of loudspeakers that image well but they don’t do anything else well. That might be what an audiophile craves for but what they are listening for is a lot of tiny unrealistic detail because the loudspeaker can’t do anything else.

    But where’s the tone, the realism at almost live levels and the micro dynamics that help a listener visualise the sound of individual musical instruments?

    I couldnīt aggree more on that!

    Thatīs actually what I love JBL for, the live-like and very dynamic sound. Actually imaging isnīt that important to me at all. But I worry about good driver integration.



    https://de.wikipedia.org/wiki/Elbphi...e,_Hamburg.jpg

    Unfortunatelly everything was amplified...
    Last edited by Mr. Widget; 01-31-2020 at 08:48 AM.

  8. #23
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    Quote Originally Posted by Dr.db View Post

    ....Thatīs actually what I love JBL for, the live-like and very dynamic sound. Actually imaging isnīt that important to me at all. But I worry about good driver integration.....
    Live, life-like sound can only come from speakers with good driver integration. Speakers with good driver integration will image well. It goes hand in hand. Any horn speaker can be dynamic, but to have natural reproduction of instruments, voices, and venues, time alignment, phase, matched dispersion at crossover, etc.(integration) are critical.

    Here's a good example. A recent review of a Klipsch horn speaker from Stereophile. These were great speakers when first implemented, but not so much today. I've linked just the measurements page. Look at the impedance plots and most importantly, the step response. Between 1.5ms-6ms delay between drivers. That's approaching 1st reflections delay. That speaker will never sound right, but will be dynamic. Many will like it for that reason alone, and that's fine. Note JAs comments at the end.

    https://www.stereophile.com/content/...r-measurements

  9. #24
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    Compare to the review of the 1400 Array measurements from (yikes) almost a decade ago. Good driver integration, great FR, good time alignment (especially for horns on a passive network), and (because of those things) excellent imaging. Plus, good dynamics.
    https://www.stereophile.com/content/...r-measurements

    From the review:
    "Conclusions
    JBL's Synthesis 1400 Array BG impressed me with its three-dimensional imaging, impressive transparency, ambience retrieval, capacity to "disappear," and fine timbral detail. It gave my similarly priced reference speakers, the electrostatic Quad ESL-989s, a run for their money for its excellent balance across the audioband, its good timbral retrieval, and its three-dimensional imaging—and it exceeded the bass-shy Quad in its reproduction of pipe organ and percussion and its ability to play much louder.. . "

  10. #25
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    Quote Originally Posted by rusty jefferson View Post
    Live, life-like sound can only come from speakers with good driver integration. Speakers with good driver integration will image well. It goes hand in hand. Any horn speaker can be dynamic, but to have natural reproduction of instruments, voices, and venues, time alignment, phase, matched dispersion at crossover, etc.(integration) are critical.
    Some of the most coherent, lifelike speakers that I've ever owned have been KEF Uni-Q coaxials (and 1 way Walsh's) ... I seem to recall that JBL made a coax (LE14C ?).

    question is: why haven't coaxials been more successful ? (except in car audio)

    they seem to fulfill most of the requirements that Rusty enumerates.
    Learn to forget

  11. #26
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    Vertical alignment vs offset certainly shows up on the RTA as peaks and dips.

  12. #27
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    @Rusty: Youīre absolutly right, these parameters cannot be seen isolated. Thanks for the informative articles.

    @Tod: The question still remains: where about is the threshold for this being audible for the human ear?? Maybe 8" off center at 850hz is unaudible, but 8" at 1200hz is audible?

  13. #28
    Senior Member Ian Mackenzie's Avatar
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    You can easily determine this with a modular loudspeaker project.

    That said the sensitivity to a variation in the distance between left and right drivers is going to increase where the listening position forms an equilateral triangle. Other factors include the symmetry of the loudspeaker locations in the room. You can validate this by moving your own system enclosures closer or further apart. Relatively small distances are audible. You can then estimate the threshold of variation by careful listening to midrange sounds and then higher frequency sounds. You might call this a linear distortion of the image. Where the drivers are not symmetrical it would be non linear.

    Toe in of the loudspeaker also has an impact on the image. In the case of the DD67000 the is already done with the angle of the woofer baffle to some extent. Was that done by design or anaesthetic is unknown. Given the width of the enclosures off the cuff l would say it was done to account for any fall off in the polar response of the inner woofer near crossover point. Toe in of a wide enclosure is never going to please the WAF factor. I would point out a wide enclosure like the DD67000 imposes limitations on adjustments to the distance between the horns in all but very wide rooms.

    In my own experience bringing the mid range closer below 1000 hertz leads to the perception of centrally coherent vocals. On the other hand moving the horn and high frequency drivers closer can shut down the image beyond a certain point producing a less open soundscape. So it’s a balancing act.

    Back to Olaf’s point l think Olaf is concerned with localisation of the source (the drivers). My feedback on that is the impact is on the sound stage or sound cape. Once the drivers blend and you have the equilateral listening position what your hearing is the soundstage not the point of localisation of the woofer/mid woofer.

    This is my analysis at this point and may serve to more discussion on this topic.

    No doubt you all have your own thoughts on this.

  14. #29
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    Double Slit Interference or Interferenz am Doppelspalt is the reason for the lobing

    The slit is a simplification here, it shows the problem in one plane instead of two. There is also an article in Wikipedia about "Acoustic Lobing".


    Consider two drivers, each sending soundwaves. At some points in space the sound waves arrive with equal phase, they will add. This is constructive interference.

    At some other points in space the sound waves arrive with a phase difference of 180 degrees, they will subtract, null each other. Tis is destructive interference.

    There is plenty of articles about this.

    Ruediger

  15. #30
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    Very useful input, thanks

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