Loudspeakers and room as a system

[graaf]

Originally posted by Pan

About the stereo triangel.. have you tried other angles? 22-23 degrees use to give best results for me with boxes and open baffles.

22-23 degrees - but which angle?

Originally posted by Pan


My solution?
I bought a house so I can go crazy with a dedicated room, big if needed.

good for You! You lucky guy!
perfect solution for lucky guys like You!

best,
graaf

[Pan]

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

[graaf]

Originally posted by thinkbad
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

Originally posted by thinkbad


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

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

[thinkbad]

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

[c2cthomas]

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?

[thinkbad]

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

JB

[c2cthomas]

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/showd...number=264-815

[c2cthomas]

Originally posted by graaf

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/showt...06#post1488406 The guys here have done a lot of work that might apply here.

[graaf]

Originally posted by c2cthomas
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.

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

Originally posted by c2cthomas


Looks as if there has been a thread about "ambiophonics" here for awhile - http://www.diyaudio.com/forums/showt...06#post1488406 The guys here have done a lot of work that might apply here.

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

[c2cthomas]

Originally posted by graaf

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! At my age it could come in handy for a nap!