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Thread: Greetings from Whitledge Designs!

  1. #11
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    Quote Originally Posted by durwood View Post
    ...There are many other things that make me go :hmmmm: (like starting with 8" woofers used for subwoofers in a large vehicle space), but then again my simple practical cost effective mind probably won't understand...

    ...According to Robert Harley, “More often than not, subwoofers degrade a musical system’s playback performance. Either the subwoofer is poorly engineered (and many are), or the subwoofer is set up incorrectly.” Mr. Harley continues, “The subwoofer may move lots of air and provide deep extension, but a poorly executed subwoofer often adds a booming thumpiness to the low end. Rather than increasing our ability to hear what’s going on in the bass, a subwoofer often obscures musical information.” Mr. Harley adds, “ … a subwoofer can fail to integrate musically with the main loudspeakers. Very low frequencies reproduced by the subwoofer sound different from the midbass produced by the main speakers. The result is an extremely distracting discontinuity in the sound of the acoustic bass in different registers.” Mr. Harley remarks, “Another factor that can make integrating a subwoofer difficult is matching a slow and heavy subwoofer to taut, lean, and articulate main speakers. Subwoofers often trade tight control, pitch resolution, and lack of overhang for greater sensitivity or deeper extension.”11 Steve McCormack, a world-renowned home audio component designer with over 33 years of critical listening experience, has heard a variety of subwoofer systems throughout his career, and pointed out that subwoofers, in general, suffer from integration problems, especially those much larger than 304.8 mm (12 inches) in nominal diameter. Rather than use a large subwoofer from another manufacturer, Mr. McCormack recommended that I consider using a plurality of Dynaudio’s largest woofer transducers, the MW190s, in an isobaric configuration.12 According to Vance Dickason, when two drivers are mounted either back-to-back or face-to-face, and driven electrically out of phase, odd-order non-linearities are cancelled and the result is substantially reduced driver distortion. One of the major advantages of the isobaric design is the enclosure volume is half of that required for a single driver, however, the output is the same as a single driver.13 ...

    ...

    ...It is worth noting the effective cone area of three MW190s is essentially equivalent to one transducer with an effective cone diameter of 390.9 mm (15.39 inches). This is essentially equivalent to that of a typical commercially available 18-inch diameter subwoofer. Instead of using one heavy cone, the proposed design benefits from the lower moving mass of three lighter cones. I believed the proposed subwoofer design would maximize bass quality and result in exceptional integration with the front sound stage, while at the same time delivering considerable power and bass extension...

  2. #12
    Junior Member Whitledge Designs's Avatar
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    Dear durwood,

    I suggest you read my articles completely before you offer illegitimate criticisms.

    The Magic Bus, in its unfinished state, had only two front seats. It now has two front seats and a bench seat with two, 3-point safety belts, thereby accommodating two more occupants. The Magic Bus, in its fully completed form, safely seats four.

    The Magic Bus, in its first proof-of-concept stage, employed six Dynaudio MW190 loudspeaker transducers, arranged in three isobaric pairs. They were powered by one Genesis Dual Mono Xtreme, capable of delivering about 1100 W of power. The effective cone diameter of the MW190s was 8.81 inches, not 8 inches, as you claimed.

    The Magic Bus currently uses three Dynaudio Esotar 1200 subwoofers, each powered by a Genesis Dual Mono Xtreme, which delivers about 1100 W of power. The effective cone diameter of the Esotar 1200 is 9.17 inches. Three of these subwoofers combined provides for an equivalent single-transducer cone diameter of 15.86 inches, driven by about 3,300 W. By anyone’s measure, this is a large and powerful subwoofer system.

    For my purposes, I prefer “stereo” reproduction. If you prefer otherwise, I’m fine with that.

    - Jon
    Designer and builder of the "Magic Bus", "The World's Best Car Stereo" ("the abs!olute sound®" magazine, Dec 2008, Issue 188)

  3. #13
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    Quote Originally Posted by AAAAAAA View Post
    ...According to Robert Harley,
    Robert Harley must be functionally deaf, based on the untethered-from reality tripe that is his stock and trade. His reviews and books also show him to be entirely incompetent when it comes to the science of audio.

    Including most of what you posted.

    Anyone who does anything in audio based on Robert Harley's idiocy automatically loses credibility with anyone who approaches music reproduction more seriously.

  4. #14
    Junior Member Whitledge Designs's Avatar
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    Dear DS-21,

    I’ve reached the conclusion that there is likely no answer I can provide that will satisfy your curiosity. Therefore, I will no longer try. In my mind, the inability to answer your question(s), in a manner that meets your standard(s), is inconsequential and unimportant.

    In a former post, I asked you to explain why I’m swamped with home and car audio enthusiasts every time I exhibit - yet you failed to address the question. In addition, it appears that you prefer not to share information about your academic and industrial credentials along with pictures of your mobile audio system. You seem to be unwilling or incompetent to answer my question and share information about yourself and your mobile audio system. Why?

    - Jon
    Designer and builder of the "Magic Bus", "The World's Best Car Stereo" ("the abs!olute sound®" magazine, Dec 2008, Issue 188)

  5. #15
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    Quote Originally Posted by DS-21 View Post
    Robert Harley must be functionally deaf, based on the untethered-from reality tripe that is his stock and trade. His reviews and books also show him to be entirely incompetent when it comes to the science of audio.

    ...
    I quoted something from Whitledges article. Be it as it may in regards to your feelings towards Harley, the benefits of going isobaric with reversed push pull drivers does, according to many sources, lessen distortion, I doubt you will argue with that and if Harley is what led Whitledge to use that technique then it doesn’t seem like it was such a waste of time wouldn't you agree?

    I have read several of the pages and there is a lot of content in there, one would have to go through a ton of content over on DIYMA to get what he has combined into a nice series, and most of it fall is line to what the DIY community does or tries to do. I haven’t seen any magical crap or grand claims, just solid info with some product marketing in between. You may or may not agree with everything he did or what some of the people that helped him along are, but there is a strong underlying scientific principle behind his work IMO. There are lots of techniques, approaches, calculations for everything he did.

    Read his article and read past some of the product marketing in there, this guy seems to be just like us, all be it more extreme.

    I am not sure why I am feeling the need to come in here and type this up for a guy that I never heard of until today. Definitely, you guys are jumping to conclusions and asking questions when everything is already there. I am doing the equivalent of yelling search to the guy asking what sub he should be using.

  6. #16
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    Quote Originally Posted by AAAAAAA View Post

    Durwood: he does say "...IASCA’s competition CD contains musical information in a two-channel stereo format. Fortunately, this is the format I believe best reproduces music..."
    I live in the real world, and it doesn't matter what IASCA uses. One should always use real world examples. Lots can be done with 2 channels of information.

    Quote Originally Posted by Whitledge Designs View Post
    Dear durwood,

    I suggest you read my articles completely before you offer illegitimate criticisms.

    The Magic Bus, in its unfinished state, had only two front seats. It now has two front seats and a bench seat with two, 3-point safety belts, thereby accommodating two more occupants. The Magic Bus, in its fully completed form, safely seats four.

    The Magic Bus, in its first proof-of-concept stage, employed six Dynaudio MW190 loudspeaker transducers, arranged in three isobaric pairs. They were powered by one Genesis Dual Mono Xtreme, capable of delivering about 1100 W of power. The effective cone diameter of the MW190s was 8.81 inches, not 8 inches, as you claimed.

    The Magic Bus currently uses three Dynaudio Esotar 1200 subwoofers, each powered by a Genesis Dual Mono Xtreme, which delivers about 1100 W of power. The effective cone diameter of the Esotar 1200 is 9.17 inches. Three of these subwoofers combined provides for an equivalent single-transducer cone diameter of 15.86 inches, driven by about 3,300 W. By anyone’s measure, this is a large and powerful subwoofer system.
    I see no illegitimate criticisms, your website clearly states in multiple places 6x MW190 woofers, and are you really going to argue about that 0.81 inches? Are you one of those types that focuses on little tiny details while missing the big ticket items? My point is not illegitimate as proven by your upgrade to larger more capable drivers. ;) Perhaps you should update your marketing info (website), and make comments on past failures if you really want to "teach" and aide in improving this hobby as you put it.
    Last edited by durwood; 09-06-2011 at 02:17 PM.

  7. #17
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    Durwood, I think you and I think a like on many things. For one, I use logic 7 and find it superior then stereo. so I to would find a debate on why use stereo over some form of surround sound, it would be great, perhaps another topic? (I know this is one of your peeves or specialties and has often been debated on other forums)

    As for switching woofers, who doesn't like trying new things, new equipment? We all do it, is he so different? Sometimes we change for the sake of change, other times we do it in hopes of getting better results over already good results even if they might end up being tiny. I can't see him changing and modifinyg his install as sometihng to use against the guy. We all know this hobby is always about changing, I couldn't imagine him making his bus once and then stopping there. He must love this stuff as much was we do. Don't you think?

    I welcome this guy and hope you guys don't run him off haha.
    Last edited by AAAAAAA; 09-06-2011 at 02:25 PM.

  8. #18
    Founding Member OSN's Avatar
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    Quote Originally Posted by Whitledge Designs View Post
    In a former post, I asked you to explain why I’m swamped with home and car audio enthusiasts every time I exhibit - yet you failed to address the question.
    In fairness, he did address this with a comical analogy about PT Barnum. Anyways, OSN wishes Jon luck with his Magic Bus. :cheers:

  9. #19
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    Quote Originally Posted by AAAAAAA View Post
    I quoted something from Whitledges article. Be it as it may in regards to your feelings towards Harley, the benefits of going isobaric with reversed push pull drivers does, according to many sources, lessen distortion,
    [EDIT]Well, for starters according to JW he has abandoned the isobaric approach, using three drivers instead of six now.[/EDIT]

    But you're wrong on fact. All going isobaric does is waste driver motors. One gains the ability to use a smaller box for a given Q, but also gives up half the efficiency.

    Basically, isobaric loading is an antequated method of getting more more extended bass response in a smaller cabinet volume, nothing else. In the modern age we use DSP for that. It allows us to use fewer drivers, and not sacrifice efficiency over the whole bandwidth of the system.

    Now, standard push-pull mounting has been shown to reduce even-order distortion. The degree to which that is audible is up for debate. (Not to mention that with many drivers any beneficial effects are swamped by the increased motor noise from an inverted driver. In fairness, the Dyn's are pretty crappy subs. They don't have much xmax, so motor noise is less likely to be a factor with them.)

    Quote Originally Posted by AAAAAAA View Post
    I doubt you will argue with that
    See supra.

    Quote Originally Posted by AAAAAAA View Post
    and if Harley is what led Whitledge to use that technique then it doesn’t seem like it was such a waste of time wouldn't you agree?
    No. I would think it's a gigantic waste of time. Bass is the easiest thing in the world to get right, anyway. Everything else is much harder to get right in a car than sub-80Hz stuff.
    Last edited by DS-21; 09-06-2011 at 04:51 PM.

  10. #20
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    Quote Originally Posted by Whitledge Designs View Post
    In a former post, I asked you to explain why I’m swamped with home and car audio enthusiasts every time I exhibit - yet you failed to address the question.
    Jon,
    FWIW, he did address this question directly by demonstrating the problem with the conclusions you're drawing from the number of spectators who come. He used an analogy to show that just because someone watches something doesn't mean they necessarily want it for themselves. In fact, I think there's ample evidence that your choice of vehicle isn't exactly a hot commodity these days. Just look at sales figures. Normalize by price, even.

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