Celestion System 6000 loudspeaker system
Monopole Mid-High with dipole subwoofers. Circa 1996
www.stereophile.com/floorloudspeakers/892/index.html
Monopole Mid-High with dipole subwoofers. Circa 1996
www.stereophile.com/floorloudspeakers/892/index.html
Yes, exactly.
This is a good thing to know, especially with low mass full-range drivers where the resulting resonance can seriously disturb both the linear behavior of the driver, and its non-linear behavior (..and always in a negative fashion). Even most woofers should have this feature, but particularly full-range drivers and mids or dipole planar tweeters.
Sometimes the best method is a "lay-up" of 1/4 panels rather than one thick board so you can move the next successive layer of 1/4" board an inch or more away from the driver - increasing the opening (..and continue the "expansion" from there). Then you can use a router to angle those edges of each board. (..visually sort of an inversion of a Mayan Pyramid's "steps" with the rear opening getting wider and wider.)
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It's probably fine as is. You chamfered. These guys will have you going for years with suggestions and opinions.
Hmm, having done this sort of thing with my FE166 ES-R's - the measurements were NOT in favor of even a *good* chamfer, it needed to be excellent to avoid problems.
Ex. Here is a statement by Zaph on this topic with respect to measuring the Scan Speak Discovery 10F/4424G00:
"Be aware that the rear of the cutout MUST be chamfered or performance will be seriously compromised in several ways that effect both linear and non-linear distortion. This seems to be the case with the tests Vance Dickason presented in Voice Coil, as those results did not look very good. The driver happened to fit my baffle cutout for the Seas 22TAF tweeter, so I just took that and chamfered the back side all the way around including the terminal notches."
Zaph|Audio
Of particular note: the Scan Speak's surround is much more stable (..far less prone to "rocking") than the Fostex's.
-but if repeddler is happy with the result then it really doesn't matter.
Hmm, having done this sort of thing with my FE166 ES-R's - the measurements were NOT in favor of even a *good* chamfer, it needed to be excellent to avoid problems.
Ex. Here is a statement by Zaph on this topic with respect to measuring the Scan Speak Discovery 10F/4424G00:
"Be aware that the rear of the cutout MUST be chamfered or performance will be seriously compromised in several ways that effect both linear and non-linear distortion. This seems to be the case with the tests Vance Dickason presented in Voice Coil, as those results did not look very good. The driver happened to fit my baffle cutout for the Seas 22TAF tweeter, so I just took that and chamfered the back side all the way around including the terminal notches."
Zaph|Audio
Of particular note: the Scan Speak's surround is much more stable (..far less prone to "rocking") than the Fostex's.
-but if repeddler is happy with the result then it really doesn't matter.
Yes, but I notice Zaph only mentions chamfering on sub 4" drivers with large, obstructive magnets being used as woofers. He claims the airflow restriction causes problems (presumably in the bass where the airflow is the greatest).
The Fostex is being used here as a midrange and isn't venting right into the wall of the cutout like the little ScanSpeak does.
I know we are splitting hairs here, but I think there is less to be gained than you might think.
Then you would be wrong.
The dominate resonance (created by the cavity) is above 1 kHz for even the 8" fostex - though it effects linear movement throughout all of its bandwidth. (..it makes the drivers VC move from side-to-side increasing non-linear distortion broad-band. In the case of the fostex drivers, the centering provided by the surround is extremely weak - and not good under the very best conditions, but made substantially worse with near-cavity resonance "jostling" the driver.)
With no desire to create a tangent to this thread.. here are a few nice loudspeaker photos from Kyron Audio:
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I should note that these designs aren't being posted for any reason other than that they have open baffle elements. ...and are sometimes a bit freaky-looking.
(..plenty of problems abound with these designs as well I'm sure - for instance the GT Audio Works planar's looked like they could well have cavity resonance issues - and certainly diffraction issues (in fact I'm sure they all have diffraction issues). Still, given the mediocre recording they did sound pretty good IMO.)
Then you would be wrong.
With no desire to create a tangent to this thread.. here are a few nice loudspeaker photos from Kyron Audio:
OB speakers worthy for lord Vader
I've heard the first one last 2 years in Melbourne audio show. Hopefully they will demo the second one on upcoming A/V show in October!
Thanks to keep the pics coming guys... we don't want a gallery thread full of OB 'theories'
. They're hard to drool on!
I have a bookmark listing of Youtubes and commerical audio systems from shows with a hierarchy on performance.. at the top of the list (because of several virtues but particularly its ability to alter the sense of room acoustic based on the recording), is the Nola Grand Reference VI (..which is probably elsewhere in the thread, but perhaps not with this youtube):
HIGHEND 2012 MUNIQUE Nola Grand Reference VI - YouTube
HIGHEND 2012 MUNIQUE Nola Grand Reference VI - YouTube
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OB speakers worthy for lord Vader
..we don't want a gallery thread full of OB 'theories'
-ah, but clearly you don't know the power of the dark-side.
wow... Kronos
Now I like the look of the smaller OB the Kronos... some details here...
6moons industry features: Audio Esoterica visits Kyron Audio in Australia
No doubt still rather pricey...
Now I like the look of the smaller OB the Kronos... some details here...
6moons industry features: Audio Esoterica visits Kyron Audio in Australia
No doubt still rather pricey...