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In Reply to: vertical dispersion question posted by chocolate_lover9999@yahoo.com on March 10, 2007 at 22:26:36:
Factors that would contribute to wide vertical dispersion in various ways would be small diameter round tweeter (no thin vertical ribbons), small diameter midwoofer, low crossover point, steep crossover slope, and non-rigid drivers (operating in breakup mode rather than as rigid pistons).A strong reflection off the ceiling is likely to be detrimental, as is a strong floor-bounce reflection. Unfortunately most speakers have very wide horizontal as well as vertical dispersion right smack in the frequency region where the ear's sensitivity to loudness and distortion also peaks: Three to four kilohertz.
I hadn't stopped and thought about it until just now, but four of the five speaker brands I sell are made up exclusively of models with limited vertical dispersion, and half the models of the fifth brand have limited vertical dispersion. So I guess I've voted with my wallet in favor of limited vertical dispersion.
Follow Ups:
Is it permitted on this site to name your 5 speakers? If OK please name them.Thanks
Hi Bill,The rules permit me to answer specific questions, and that sounds pretty specific to me. If the moderators feel otherwise I'm sure they'll let me know. Here are the lines I carry, with comments on their vertical dispersion characteristics.
Listing them roughly from most-to-least expensive:
1. SoundLab electrostats, which are tall line-source-approximating dipoles. Their geometry pretty much precludes floor and ceiling reflections. These are by far my most directional speakers in the vertical plane.
2. Gradient, which uses a coaxial mid/tweet unit wherein the midrange driver's cone acts as a waveguide to control the radiation pattern in the lower end of the tweeter's range.
3. GedLee Summa, a large high-efficiency speaker that uses a 90 degree constant-directivity round waveguide to control the radiation pattern above the 1 kHz crossover point.
4. AudioKinesis (my house brand), similar in configuration to the Summa but on a smaller scale. I'm also working on a coaxial model or two, which would resemble the Gradients in dispersion characteristics.
5. Gallo Acoustics. The MTM format of the Reference series has limited vertical dispersion. I don't know the frequency at which the piezo tweeter takes over but it's probably pretty high; that would make a difference because the piezo will have considerably greater vertical dispersion than the two cones will.
Hope this helps!
and says "waveguide" when speaking to conventional audiophiles. ;-)
It's not how big it is or even how you use it that matters. It's what you call it.;o)
thats a magnificent array of music reproducers,the proper way it should be reproduced!All the Best.
Thank you very much, Bill.
I'm suprised you don't carry ME Geithain and Linkwitz's Orions. You're obviously paying attention to good speaker design (where the room matters).
No market for active I suppose.
What sort of bass alignment for the house coaxials?cheers,
AJ
The threshold for disproving something is higher than the threshold for saying it, which is a recipe for the accumulation of bullshit - Softky
Hi AJinFLA,I'm also fan of Linkwitz's work, but I'm under the impression that the Orion is more of a DIY or maybe direct-sales product. Does he sell through dealers? The Gradient Revolution is similar in concept, but has better radiation pattern control in the region where I think it's most important (3-4 kHz).
The ME Geithlains are new to me. I'll have to read up on them. That big cardioid-pattern studio monitor looks quite interesting. Realistically I'm more likely to put money into my own designs than into a new product line at this time, but that does look like an acoustically very well thought-out design. Unfortunately my dealer experience leads me to believe that large stand-mount speakers are a format that is very difficult to sell.
The coaxials in my house-brand speakers will probably be loaded into a sealed sub-enclosure (to acoustically minimize cone excursion below cut-off), and then the dedicated bass section will be reflex-loaded and powered by a built in plate amp, which among other things allows the relative volume level in the bass region to be adjusted according to boundary reinforcement and/or taste and/or lack thereof. I have two coaxial designs that I'm working on, one medium-efficiency and one high-efficiency.
Best wishes,
Yes, the Orions are DIY/direct sales, but I don't see why SL would object to you selling them as a dealer. Perhaps I'm wrong :-).
The Gradient is similar in the bass region. IIRC, Geddes did a DBT where the Revolution and Summa were a statistical dead heat. I can't seem to find a link anymore. Linkwitz has now added a rear firing tweeter that maintains directivity control above the midrange (horz & over the top), but not vertically towards the floor. I addressed issue this myself a couple years ago when I copied his design format by using a shallow WG on the tweeter. I have since reverted to coaxials (used previously before my Orion copy).
I'm surprised you hadn't heard of the MEGs before. Their flow resistance technique for the big cardioids is quite interesting, as is the OB coaxial mid mounting w/ rear absorption. You did see the "home" version monitors yes? http://www.me-geithain.de/index2.html?eng
Did Earl's paper http://www.aes.org/e-lib/browse.cfm?elib=13722 convince you that GD (such as your reflex design) is not audible?
No cardioid considered even though going active bass?cheers,
AJ
The threshold for disproving something is higher than the threshold for saying it, which is a recipe for the accumulation of bullshit - Softky
Hi AJ,I doubt the Orions have any room in their pricing structure for a dealer to make his nickel. That's one of their attractions - they're an excellent value, as the price is at least 40% less than it would otherwise be. I sell mine direct as well.
The Gradient Revolution in Earl's blind (not double-blind) test was mine. I brought it from New Orleans to Michigan, and your recollection is correct - it came out pretty much tied for first place with the first prototype B&C Summa.
The only way I know to get a cardioid radiation pattern in the bass region is expensive in terms of box volume, efficiency, bass extension, and money. I may try it some day, but right now I think there are other areas where a more cost-effective improvement can be made. I would love to know what the innards of a MEG cabinet look like, and what materials they are using. They are probably using techniques that I don't know.
While my coaxial system could be called "semi-active", it uses an off-the-shelf plate amp for the powered woofer section. You see, to get a customized plate amp for something like a cardioid pattern bass system, I'd have to buy at least 500 units. And I don't have that kind of money.
I chose a reflex enclosure for my bass system because, if properly executed, I think reflex loading does the most things right for the money. Reflex loading gives me enormous flexibility - I can essentially pick a target bass frequency response curve and with a little bit of effort design something that approximates that target. I probably use a different target from most designers, though I got my ideas mostly by paying attention to John Wolff of Classic Audio Reproductions.
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