The Advantages of Floor Coupled Up-Firing Speakers

Oh, I meant 22-23 degrees out from the midline to each speaker.

Midline being the line from the listener that passes between both speakers.

May be difficult for you with your set up if the room is wide since you need to move the listenig position further back.


/Peter
 
thinkbad said:
graaf, extent your idea even further.

Place LS in the corner, normally the worst possible position for a conventional speaker. Now, you get even more boost at low freq and your 2 walls and the floor can be assumed to be a BIG baffle, and at the same time the adjacent walls are as far away as possible.


yeah! :) I have considered this corner positioning too!
it is worth trying and I will try it in my new room as well
actually this is more or less what I have now - one speaker is exactly in the room corner and the other one has tall 30 cm deep bookcase to the side. But all this is provisional and rather for background listening. I cannot judge it finally
From theoretical point of view You certainly get more very early reflections (VER) in corner positioning and also You excite all the room modes so problems with bass response can arise. I am not confident enough of this corner placement to recommend it without caveats

thinkbad said:


Maybe a Visaton B200 stuck deep into the corner without enclosure or even baffle. Suspend the driver from the ceiling or mount it to a backbone of some sort. Stuff the walls next to the speaker and drive it with a transconductance amp.

Well, just an idea :D


I think that this idea is great!
There is a saying attributed to Albert Einstein: "If at first, the idea is not absurd, then there is no hope for it" :)

best,
graaf
 
From theoretical point of view You certainly get more very early reflections (VER) in corner positioning and also You excite all the room modes so problems with bass response can arise. I am not confident enough of this corner placement to recommend it without caveats


Well, placing the speaker at the tricorner where you have pressure-maximum certainly exite all the modes, actually I suppose you get a more EVEN bass response, althrough irregularities may present itself at higher frequencies.

Regarding VER, listening at nearfield distance you can probably place the first detrimental reflections BEHIND your listening position and place some kind of diffuser at the backwall or use strategically placed furniture :)

JB
 
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Hmmm...... been thinking (sometimes a risky thing for me :D ) What about an array of speakers along each wall - the left wall being the left channel - the right wall being the right etc. and using like 4 or 5 speakers placed along each wall (aimed upwards to reflect off of baffles) - perhaps with a variable delay line for each speaker? :scratch1:
 
Hmmm...... been thinking (sometimes a risky thing for me ) What about an array of speakers along each wall - the left wall being the left channel - the right wall being the right etc. and using like 4 or 5 speakers placed along each wall (aimed upwards to reflect off of baffles) - perhaps with a variable delay line for each speaker?

Sure, you can control the wavefront to some extent, provided you have enough drivers.
You can even use high-quality drivers for left/right and inferior (inexpensive) drivers in the delay-line.
Nevermind the complexity :eek:

JB
 
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JB - the thinking behind using more speakers is that it should break-up the room nodes into smaller areas - perhaps small enough to be effectively zeroed out for all practicable purposes. Also you could use larger arrays for larger rooms and smaller arrays (more speakers) for smaller rooms - at bit of testing could result in determination of an effective matrix of speakers. :)

Using a mess of these with some good Subs might be worth thinking about. Space them about every 2 ft. (600 mm) and drive each from its own amplifier for volume adjustment and individual delay. http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=264-815
 
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graaf said:

You mean AMBIOPHONICS? (www.ambiophonics.org)
I was inspired by ambiophonics when I tried something like this. I built rectangular box 23x23x23 cm with wide rangers of the size of JX92s on opposite sides.
What I was trying to achieve was an "ambiopole" i.e. "crosstalk-cancelled stereo array" without physical barrier or electronic cross-talk cancellation, which are normally required (alternatively).
I was relying just on the directivity of the drivers and of the cabinet.
graaf

Looks as if there has been a thread about "ambiophonics" here for awhile - http://www.diyaudio.com/forums/showthread.php?s=&postid=1488406#post1488406 The guys here have done a lot of work that might apply here. :D
 
c2cthomas said:
Hmmm...... been thinking (sometimes a risky thing for me :D ) What about an array of speakers along each wall - the left wall being the left channel - the right wall being the right etc.

this is exactly the speaker positioning recommended by Harold Beveridge for his line source electrostatics

c2cthomas said:


Looks as if there has been a thread about "ambiophonics" here for awhile - http://www.diyaudio.com/forums/showthread.php?s=&postid=1488406#post1488406 The guys here have done a lot of work that might apply here. :D

I am not into ambiophonics. Having a mattress in the middle in the room is not my dream ;)
I also believe that ambiopole effect can be achieved with positioning recommended by Beverdige: http://www.bevaudio.com/White_Paper.htm

best,
graaf
 

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graaf said:

this is exactly the speaker positioning recommended by Harold Beveridge for his line source electrostatics

I am not into ambiophonics. Having a mattress in the middle in the room is not my dream ;)
I also believe that ambiopole effect can be achieved with positioning recommended by Beverdige: http://www.bevaudio.com/White_Paper.htm

best,
graaf

I will check out the Beveridge site ASAP - thank you for the tip!

Sometimes having a mattress in the middle of the room can be a good thing! :D At my age it could come in handy for a nap! :rolleyes:
 
>What about an array of speakers along each wall - the left wall being the left channel - the right wall being the right etc. and using like 4 or 5 speakers placed along each wall (aimed upwards to reflect off of baffles) - perhaps with a variable delay line for each speaker?


In the early 70s Ted Jordan wrote an article describing a system which used a line of 20+ fullrange units along the wall in front of the listener. The driver at each end faced the listener, the others all faced down and they were linked by delay components. I don't know that he pursued it because he moved onto his linear array systems.

The long line was meant to address stereo imaging rather than room acoustics. The same article describes a cut down version which used a central group of drivers and reflectors left and right. 20 years ago I thought that worked quite well but I haven't tried it recently with more revealing components.


Interesting discussion, chaps. It's too easy to forget about the room and DIYers have a much better chance of doing something interesting to make the speaker and room fit better.
 
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Colin - Thank you for that bit of information - interesting, I guess that it is true that everything that's old is new again. Well - if I'm thinking along the lines of TJ (hmmm…… my initials are TJ as well - hmmm……….nah - forget it) then it's all good - even if I am 20 years late. :cool:

This sort of project might give me an excuse to try out some of his JXR6 HD's in a line array and do a poor mans version of a Beveridge type of speaker arrangement. I guess it's a good thing that I don't have gobs of money sitting around - I would need to buy a second house to put all my audio gear in! :D
 
c2cthomas said:


This sort of project might give me an excuse to try out some of his JXR6 HD's in a line array and do a poor mans version of a Beveridge type of speaker arrangement.

perhaps a VMPS sort of waveguide could be employed to lower the horizontal directivity of such a line array and to have more uniform and wide horizontal polar response?

http://www.vmpsaudio.com/

Beveridge also used waveguides for that purpose

best,
graaf
 
Ted's array is intended to be directional, to give the precedence effect he prefers for a stable stereo image. He then prefers to wall mount the drivers to reduce baffle step requirements and rear reflections. In his own system, the two arrays are widely separated, almost in the room corners, so the image does hold over a wide horizontal area. I've heard it a number of times and the only downside is mild loss of HF when your ears are significantly above the level of the array. (Albeit this is listening quite close to the array - farther back may have less effect on HF.)

But this may be getting off topic ...
 
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graaf said:

perhaps a VMPS sort of waveguide could be employed to lower the horizontal directivity of such a line array and to have more uniform and wide horizontal polar response?
http://www.vmpsaudio.com/
Beveridge also used waveguides for that purpose
best,
graaf

Hi graff - I have always admired the waveguide concept used on the VMPS line of speakers - I think it was just a couple of years ago that they came out with that?
I have had the Beveridge patent on file for quite some time now as a result of looking at another design for electrostatic speakers and waveguides. At first look I could not figure out what all of the slots and guides were about - until I read his theory on audio wave propagation - then things came together. I visited the Beveridge web site yesterday - it's good to see that he and the company are still around and making things. It's all to rare that an individual can start out in the audio business and still be making a go of things 20 or 30 years later.
 
Colin, do you know any specific detalis with regards to TJ`s array ?
e.g distance/delay between drivers, the freq. range covered by delayed drivers, does all drivers play at the same level ?

A poor mans version could use Jordan`s for the line array and cheap Tangband`s for the delay-line...

JB
 
Colin said:
Ted's array is intended to be directional, to give the precedence effect he prefers for a stable stereo image. He then prefers to wall mount the drivers to reduce baffle step requirements and rear reflections. In his own system, the two arrays are widely separated, almost in the room corners, so the image does hold over a wide horizontal area. I've heard it a number of times and the only downside is mild loss of HF when your ears are significantly above the level of the array. (Albeit this is listening quite close to the array - farther back may have less effect on HF.)

But this may be getting off topic ...

not at all :)
high directivity speaker in (or close to) a room corner and significant toe-in is also a reasonable method of dealing with early relfections, of "speaker-room interface", like in case of classic corner horns
this can be achieved also with "matrix" (I am not sure of the word) array like 4x4, I mean like this:
o o o o
o o o o
o o o o
o o o o
especially on an open baffle
Beveridge is different - a line source, low directivity speaker on the opposite walls
in a corner - high directivity, on the opposite walls - low directivity
it makes sense both ways
and to this let's add:
Schupbach - Stereolith (with reservation concerning incompatibility with some recordings)
Carlsson - omni just above the floor and close to the same long wall or in corners
my humble proposition - omni just above the floor and against opposite walls
etc. etc.
all good ideas (or at least I hope - this remark refers to my own idea ;) )

it's all about consistency in applying them

and there is more! :)
and what about JBL Paragon "reflecting" principle for example?

many, many interesting and reasoned alternatives to industry standard equilateral stereo triangle with speakers 2 feet away from walls, which is a standard that lacks any theoretical foundations and only drives "Acoustic Treatment Accessories" industry

best,
graaf
 
>Colin, do you know any specific detalis with regards to TJ`s array ?


Hi - I have the original article but there are no specifics about the delay components. The line was horizontal, using up to 20 drivers per side. They were 4 inch units (probably Jordan Watts modules, precursors of the JX92) placed closed together and all apart from the end units facing down. It was designed to look like a shelf (this was 70s decor, remember!). The units were used full range. He wasn't specifically selling his own units in the article but the Jordans satisfied the directivity criteria for it to work. So in theory, other units would work if they matched the criteria.

The current linear array, I presume, supercedes this. In one of the earlier Jordan manuals, Ted talks of using multiple 50mm units to control directivity in, for example, auditoria.

A point I've read is that the sound can seem more natural if the speakers are hidden and the listener is less conscious of the physical sound sources.
 
Colin said:

A point I've read is that the sound can seem more natural if the speakers are hidden and the listener is less conscious of the physical sound sources.

did Jordan wrote this?
I ask because this is exactly the conclusion I have come to after my own experiments

as I have written above in this thread, about the secret of peudo-ambiopole (Stereolith) being that:
our hearing is unable to locate the speakers as a distinct sources of sound