The Advantages of Floor Coupled Up-Firing Speakers

When someone brings up string instruments, a grand piano being at the top of this pinnacle instrument wise due to it's size / range, I wonder how one would recreate it's broad range acoustic center / highly reverberant sound field. Grands being laid out on a large horizontal plane acoustically reflects the similar sound a true FCUFS. Room constraints impose additional reflections that are not part of the original. If we were in the same room reproducing this we would effectively be emulating the original, but with our laughably small rooms, only mess this original mix up. That being said we shouldn't loose sight of what that original IS. It's an issue I'm sure many have pondered, most tossing out an up firing array in the trash due to the mess we've created, thinking logically that only forward firing is the only way to constrain these limitations. This has evolved into some of the more advanced designs, constant directivity / controlled directivity and believe based not on my own experience but those of others and the science behind it, would be the Synergy Horn. My hats off to Tom Danley for that.
On the opposite side of this coin of course is upfiring with all it's not so obvious complications. To me, have never heard a piano reproduced so well. This is where I have to agree with Graaf. He has that piano and can do a direct comparison. For the lack of a better word, 'Ambiance' an FCUFS provides like that of a piano. The reason I mention piano so much is that next to no speaker ever made does this "right". Years ago both my Father and Grandmother would say that was the most unrealistic sounding instrument they've ever heard and is what I should strive for. Took it upon myself to take the time to really hear what all these instruments really sound like up front in person and in different venues at distance.

The appreciation of what this provides is complicated, but more natural sounding experience, that like the real event. Also note that quality recordings sound better this way, direct in your face synthetic sound comes off sounding poorer than intended. Sadly this is the majority of recordings done. I'm sure in part the reason we have this controversy today is mostly lead by the recording industry's misunderstanding of how to record. It's the blind leading the blind.
 
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" I'm sure in part the reason we have this controversy today is mostly lead by the recording industry's misunderstanding of how to record. It's the blind leading the blind. "

Suits you, Sir! Grand piano is a terrific instrument, and a terrible challence to record! I find every recording sound different! It comes from the piano, mic positioning, room/hall, mixing table(effects, panning), th mixing room acoustics, recording engineer's taste, mixing engineer's and producer's taste - all together, never the same.

I would like to see a description of mic postioning and recording techique in the footnotes of an album. Usually they are mixed from nearfield and room mics. -some choirs and big orchestral works are from just a XY or Blumlein in the hall. Binaurals are rare.

Life gets easier when we remember, that instruments/orchestra always sounds different in live concerts too!
 
A funny thing.. I'm at my summer cabin now, listening to a pair of "wall-coupled" Sonab OA-13. Radio broadcast had a lady singing in a whispering voice (didn't catch who) and the highs of whispering were swinging and undulating around the room in an unpleasant way. I have noticed that earlier here too. Generally I like the sound of them in this room. It might have been a mix effect too, but i doubt that.

I haven't done RT/EDT analysis of this room, but my educated guess is that room RT/EDT are fairlly low, this is all wood but not logs. Usually I get wonderful sound here and eg. live acousic guitar sounds marvellous! Obviously the hsss was at some reverberance maximum.
 
... and the highs of whispering were swinging and undulating around the room in an unpleasant way. I have noticed that earlier here too. Generally I like the sound of them in this room. It might have been a mix effect too, but i doubt that.
Apart from any room reflections - whisper lacks lower frequency content and significant initial transients. This robs our hearing of clear localisation clues in the stereo scene.

Rudolf
 
This thread is black of ashes as it has been reborn so many times like feenix :D


2) panned full L or full R

(tend to) seem to be coming from the speakers.


There is a solution ! 3 speaker linear stereo matrix :) With the matrix a speaker cannot be localised as there are 3 of them playing all the time.



But the effect IS real and some recordings (crappy recordings IMHO but nevertheless) under some circumstances suffer audibly from it.

I've been enjoying 3 flooders played through the matrix, and even the crappiest recordings got immediatelly improved and became almost pleasurable.
 
This thread is black of ashes as it has been reborn so many times like feenix :D

always back in black :p


There is a solution ! 3 speaker linear stereo matrix :) With the matrix a speaker cannot be localised as there are 3 of them playing all the time.

it definitely makes sense! :up:

Can we say that the problem of the sound coming from the floor effect is solved by the matrix? Would be great news!


I've been enjoying 3 flooders played through the matrix, and even the crappiest recordings got immediatelly improved and became almost pleasurable.

How does the 3xFCUFS matrix compare to the original stereolit-like single box one?
 
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next to be tested:

interesting "no direct sound" placement method: Stereo Unlimited tweak

below is what I am talking about (please take A CAREFUL NOTE OF the db scale! :D :cool:):

I think it results hole in the middle. Side wall reflections arrive in very wide angle, AND there is no strong center sound.

it depends on the stereo triangle in the room geometry and in particular on the toe in of the dipole null axis in the direction of the listener

with the right geometry there is a center sound - in form of reflections from the front wall
 
generally it appears to be a consensus in literature that frequency range critical for localisation perception is >0.5 kHz

I suggested above (and with some good reasons I believe) that the important range extends roughly 0.4<4.0 kHz

it is desirable to have 0 phase rotation of the harmonics, Griesinger showed a reason why. It all comes down to separating individual sound-streams in a 'busy' environment - coctail-party-effect. This is most effective when the harmonics have the same time-delay, so that the waveform doesn't get smeared.


The phase needs to have constant group delay from 700 - 7 kHz as Griesinger says
 
is that so? why?

BTW new Swedish flooder:

OD-11 - Teenage Engineering

http://assets.sbnation.com/assets/1967869/OD-11_Flyer.pdf

teenageEnOD01.jpg
 
Graaf,

The three quotes you listed in #3172 are all good reasons not to point speakers at the ceiling.

why?

Exactly what is wrong with lowering the level of the floor reflection at the expense of a higher level of the ceiling reflection?

What does it have to do with phase rotation of the harmonics or smearing of the waveform?
 
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Originally Posted by weltersys
Graaf,

The three quotes you listed in #3172 are all good reasons not to point speakers at the ceiling.

why?

Exactly what is wrong with lowering the level of the floor reflection at the expense of a higher level of the ceiling reflection?

What does it have to do with phase rotation of the harmonics or smearing of the waveform?
What is wrong with less floor and more ceiling reflections is I find it preferable to have floor and ceiling reflections to appear naturally as they would in a normal presentation. Your preference is quite different.

1)generally it appears to be a consensus in literature that frequency range critical for localisation perception is >0.5 kHz
I suggested above (and with some good reasons I believe) that the important range extends roughly 0.4<4.0 kHz

In either case, the lower range is localized at the floor, upper range from the ceiling reflection.

2)it is desirable to have 0 phase rotation of the harmonics, Griesinger showed a reason why. It all comes down to separating individual sound-streams in a 'busy' environment - coctail-party-effect. This is most effective when the harmonics have the same time-delay, so that the waveform doesn't get smeared.
Again, upper harmonics, being more directional, are reflected from the ceiling, while fundamentals are heard from both floor and ceiling, multiple different delay times.

3)The phase needs to have constant group delay from 700 - 7 kHz as Griesinger says
Phase relationships and group delay are not maintained when the first arrival times are multiple reflections. The upper range, 700-7 kHz is most smeared, as most speakers are more directional in that range.

Art