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Old 13th September 2012, 07:36 AM   #1681
graaf is offline graaf  Poland
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Quote:
Originally Posted by Elias View Post
Wouldn't that be the same as placing the 1 element flooder in front corner ? No 1st order floor, 1st order side wall and 1st order front wall reflections.
- Elias
one element flooder which is horizontally omnidirectional would produce some very early 1st order side wall and 1st order front wall reflections and a strong 1st order contralateral side-wall reflection plus 1st order rear wall reflection much louder than in case of a flooded directional array
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Old 13th September 2012, 09:39 PM   #1682
Elias is offline Elias  Finland
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Quote:
Originally Posted by graaf View Post
one element flooder which is horizontally omnidirectional would produce some very early 1st order side wall and 1st order front wall reflections and a strong 1st order contralateral side-wall reflection plus 1st order rear wall reflection much louder than in case of a flooded directional array
Well, obviously it depends how one success in integration into the corner.

Contralateral reflection will reamain, sure, but at higher freqs not much if practically at all depending on the size of the driver, and anyway less than normal stereo speakers toed in.
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Old 14th September 2012, 07:12 AM   #1683
graaf is offline graaf  Poland
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Originally Posted by Elias View Post
Well, obviously it depends how one success in integration into the corner.

Contralateral reflection will reamain, sure, but at higher freqs not much if practically at all depending on the size of the driver, and anyway less than normal stereo speakers toed in.
yes, I presume imperfect integration into the corner and rather wide dispersion, perhaps wrongly, because, interestingly, with higher directivity, like in the original "Fostex 8" flooder" what flooder achieves is in fact a kind of a virtual ceiling speaker because as measurements and listening tests have shown ceiling reflection dominates over the direct sound

this is a virtual ceiling speaker with one very important advantage over a real one - a real ceiling speaker produces a very strong 1st order floor reflection, a virtual one - none

Last edited by graaf; 14th September 2012 at 07:15 AM.
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Old 14th September 2012, 09:21 AM   #1684
Elias is offline Elias  Finland
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Originally Posted by graaf View Post
this is a virtual ceiling speaker with one very important advantage over a real one - a real ceiling speaker produces a very strong 1st order floor reflection, a virtual one - none
More than once I've been thinking about ceiling speakers, and were pondering why not hang flooders. At least below about 1kHz it does not matter if a reflection comes above or below as long it has the same incidence angle relative to sagittal plane.

High freqs are different of course, and I think something coming from above is not so harmful than coming from below, since evolutionary we didn't expose much to above sounds at savannah so they are not strong indicators.

- Elias
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Old 14th September 2012, 12:46 PM   #1685
graaf is offline graaf  Poland
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Originally Posted by Elias View Post
More than once I've been thinking about ceiling speakers, and were pondering why not hang flooders. At least below about 1kHz it does not matter if a reflection comes above or below as long it has the same incidence angle relative to sagittal plane.

High freqs are different of course, and I think something coming from above is not so harmful than coming from below, since evolutionary we didn't expose much to above sounds at savannah so they are not strong indicators.

- Elias
yes, and therefore a real ceiling speaker is a bad idea and a virtual - ceiling reflection of a flooder - is good
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Old 26th September 2012, 07:54 AM   #1686
graaf is offline graaf  Poland
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accidentally I came across an interesting thread at Swedish forum: http://www.faktiskt.se/modules.php?n...=asc&list=full

James Croft participates in the discussion and he declares that Snell "Type 1" was his design and explains where the idea came from:

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Yes, I came up with the concept for the Snell Type One, but in late 1976, when I did a patent search, I found Snell's original patent (US 3,964,571) had somewhat anticipated the idea, even though he was producing only the Type A at the time. So, I contacted Peter Snell and presented the concept to him, along with sketches of my configuration and test data (Mine was 8" two way, Audax and Peerless, Snell's was 10" two way Audax all around). It wasn't very nice looking, and it wasn't very practical with a 60 cm 'tongue' sticking out for people to trip over, but the performance was rather special.
overall interesting discussion, most of it in English, the guy appreciates advantages of Beveridge placement (discussing Swedish Bremen speakers) and of flooder-type arrangement which he calls "a speaker boundary coupled close to the floor" while on the other hand he appreciates Dr Geddes' Summa as well

and here from a thread from the same forum documenting DIY-ing some Carlsson style flooders:

http://www.faktiskt.se/modules.php?n...topic&p=502903
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Old 26th September 2012, 01:21 PM   #1687
gedlee is offline gedlee  United States
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while on the other hand he appreciates Dr Geddes' Summa as well
Thanks for that link, I found it interesting. I wish that it were in English because I would like to present my side of Mr. Crofts comments since I don't agree with him on every aspect of his approach to waveguides.
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Old 27th September 2012, 06:54 AM   #1688
graaf is offline graaf  Poland
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Originally Posted by gedlee View Post
Thanks for that link, I found it interesting. I wish that it were in English because I would like to present my side of Mr. Crofts comments since I don't agree with him on every aspect of his approach to waveguides.
no language problem really, I am sure that all Swedes there understand English
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Old 27th September 2012, 09:12 AM   #1689
graaf is offline graaf  Poland
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Mr Croft's post from 2011-01-28 09:23 is particularly interesting, he comments on the fact that there were soundstage height issues with Snell "Type 1":

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the one problem with my original approach, and the production Type One, was that the image is too low... similar to sitting up in the balcony and looking down at the orchestra
now according to Mr Croft:
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It IS possible, by a few different methods, to raise the height of the sound stage with the speaker boundary coupled close to the floor.
...
The psycho-acoustics of the situation is that we receive most of our information relative to image height from frequencies above 4 kHz, at least when we keep our head perfectly vertical. in actuality, we are always tilting our heads sideways a small amount as we listen to music and this allows our ear/brain system to start to use left/right ear comparison for vertical imaging, which lowers the frequency sensitivity down below 1 kHz for vertical detection.

Even so, one approach is to use the midrange or woofer/midrange driver floor coupled, while placing the tweeter up at ear level, crossing over at about 2 to 3 kHz with precision 8th order slope crossovers to minimize lobing in the vertical polar response at and near the crossover frequency. With this approach the tweeter provides the height information ... This approach has a number of things that have to be carefully optimized to work effectively ... but it can be made to work reasonably well.

Another approach is to use both the tweeter and midrange drivers boundary coupled to the floor, and use altered frequency response above 4 kHz to mimic the pinna derived frequency changes that normally tell the ear/brain system that an image is elevated. While this can work, it tends to vary in its effectiveness depending on the listener. Additionally, the ripple that one needs to invoke to get this effect is difficult to optimize for a variety of reasons
...
Again, I must mention that there are many subtle issues that must be dealt with to make these types of approaches work well without side effects causing audible tonal and spatial colorations.
in the light of the foregoing and IF Mr Croft is right then it is easy to understand why the soundstage height is unrestricted in the case of the original flooder that is a floor coupled upfiring single 8 inches whizzer cone fullrange driver, it suffices to look at directivity plot of a typical driver of this kind:

Click the image to open in full size.

obviously most of the energy of the 1<4 kHz frequency band reaches the listener via the ceiling reflection - so the ceiling reflection effectively becomes a virtual ceiling tweeter - a virtual one because it generates no its own early 1st order floor reflection

the frequency of the "crossover" between the floor coupled "midwoofer" and the "virtual tweeter" is determined by listener's distance, ceiling height and the angle at which the fullrange unit fires upwards
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Old 27th September 2012, 11:57 AM   #1690
Elias is offline Elias  Finland
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I had similar experience with my monoflooder test.

If the speaker was facing directly or almost directly the ceiling, it was impossible to locate the speaker and sound was coming from front but not from low.

But if I turned the speaker a bit facing more to the listening area the speaker immediately become localised or the sound was coming from low angle.


Then I don't know how well Snell speaker satisfied the purpose in the first place. Maybe it never become popular for this reason, who knows.


- Elias
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