The Advantages of Floor Coupled Up-Firing Speakers

@Key:

Yes i think it would be naive to assume, that recording and mastering were
not the processes affecting imaging at most.

What is gone is gone. Most of HiFi hogwash results from whishful thinking,
that something not present on the recording could in some way be restored
by some magic. Or that something nasty on the recording could in some
way be washed away.

Only well balanced recordings can serve for judging reproduction equipment.
( OK , what is a well balanced recording, which kind (mix) of stereophonic
technique is used ...)

In my experience there are good recordings with minimalistic equipment
(just 2 microphones) but there are also very good productions which
use the whole arsenal.

A good reproduction chain - to me - is one which is
capable to produce a whole bunch of balanced recordings in an enjoyful
manner, thereby showing (not overpronouncing) their specific
characteristics.

Example sibilance:
I have some recordings with a slight tendency to
sibilance. If the reproduction chain is balanced enough, the impression
will not "keel over" into nastyness. A reproduction chain prone
to sibilance will tend to push every recording into that direction and
those marginal recordings will keel over for shure.

Example deep bass content:
How much is bass heavy ? How less is "too lean" ?
Recordings differ greatly concerning deep bass content.

A reproduction chain with well controled impulse response in the bass and
room modes excited in a balanced manner, will tolerate a greater variety
of recordings. The "fat" recordings keep listenable - given the deep bass
content is "informative" - and the bass content in the leaner recordings
can still be experienced.

Sibilance and deep bass content e.g. both affect imaging.
The bass is essential in making up a perceptive picture of the
"sound event space". Sibilance attracts our ears to the speakers
as sound sources , which can destroy any imaging immediately.

Of course there is much more to imaging on recordings, but i have taken
sibilance and deep bass content as an example.


Kind Regards
 
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e.g. for symphonic music:

Hector Berlioz, Symphonie Fantastique, Cleveland Orchestra / Lorin Maazel,
Production: Robert Woods, Recording Engineer: Jack Renner
Telarc 1985

Gustav Holst, The Planets, Le Orchestre National de France / Lorin Maazel,
Production: Roy Emerson, Sound Engineers: Guy Level, Jacques Boifgallais
CBS/Sony 1982

Ludwig van Beethoven, Symphony No. 5, Philharmonia Orchestra / Valdimir Ashkenazy,
Production: Andrew Cornall, Sound Engineer: Colin Moorfoot
DECCA 1982

Would fall into the category "early digital productions", but are recordings
i regard as high quality in "credibility" of space and imaging, brillance,
balance, low frequency content and color of the instrumental groups.

Although each different.

Kind regards
 
presumably heavy on the minimalistic side:

"Les plus belles pages de la Musique Ancienne" Polyhonia Antiqua,
Ensemble de Musique Ancienne d' Aix en Provence, Direction: Yves Esquieu
Disques Pierre Verany

A "Fest" for choir - and solo voices, spatial imaging ...


Jazz / Funk Studio Productions:

Miles Davis "TUTU"

Sadao Watanabe, "My Dear Life", Flying Disk 1986 (Tokyo)
 
ok! let's go back to the very first post

after some thinking here is (see attached scheme) a new option for the CFS speaker's placement in a room of typical proportions and appr. wxd 4x5 metres and appr. h 3 m (as in the previous example in the first post)

this placement is optimized with regard to use of very specific type of driver that is classic low Qts 8-inches fullrange like Fostex FE206E

this optimization takes into account one more "room-speaker" idea that is of "boundary room augmentation"

being very short (appr. 20 cm) the CFS speakers are likely to get most advantage from "boundary room augmentation" and as they utilize low Qts driver in a closed box "boundary room augmentation" is what they also really need to get any bass from a closed box without significant electronic correction

To get most advantage from "boundary room augmentation" I place them near the room corners with the distance of acoustic center of the speaker:
- to the floor – ca 20 cm
- to the front wall – ca33 cm
- to the nearest side wall - ca 53 cm
The chosen distances are following the golden proportion 0.62/1/1.62 just to make it nicer :)

Roy Allison's RDL spreadsheet for visualisation of "room boundary augmentation curves " is showing an upward (climbing towards the low end of course) curve that matches very nicely the downward curve of a Fostex in a closed box.
In results the final simulated response looks like -6 dB @45 Hz and -10 dB @35 Hz, not bad for such a driver in a small simple box without any electronic corrections.

and taking into account this "boundary room augmentation" the SPL max at low frequencies is ~88 dB @50 Hz and 82 dB @35 Hz within the driver's linear displacement

so much for the advantages of this CFS speaker's placement option, now on to some problems
with stereo basis of ca 280 cm and the listener's distance from both speakers (the path of first wave) of ca 250 cm:
- first reflection from the floor for such short speaker is not reaching the listener at all (just like in the previous example)
- first reflection from the ceiling is delayed by ~9 ms ( (just like in the previous example)
- first reflection from the opposite wall is delayed by ~10 ms
- first reflection from the back wall is delayed by ~14 ms

so far so good BUT "boundary room augmentation" which means abandoning of the Beveridge placement (of the previous example, shown in the first post of this thread ) comes at a price:

- first reflection from the front wall is delayed only by ~2 ms
- first reflection from the side wall is delayed only by ~4 ms

IF those reflections are indeed detrimental to the sound (which is not certain but let us assume that they are) then something must be done with them

absorbtion is one option but it is difficult for an amateur to get it sufficiently broadband and effective

but what about deflecting? Has anyone tried deflectors at home? They could be made of glass to make them less obtrusive. Or is it a bad idea?
Given that the loudspeakers are so short the deflectors could be also short and quite inobtrusive.

As shown on the attached scheme one pair of deflectors could be used to deflect first front wall reflection towards the back wall and a second pair to deflect first side wall reflections towards the back wall

What is Your experience with deflectors?
 

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You are at a point where one can ask the question: Why not go completely into the corners?
This is a concept:
The enclosure is a pyramid like in my Carlssons. A 5" minibass is located in one corner of the pyramid, as close to the walls as possible. This allows corner loading up to 1 kHz. Above that a horn tweeter takes over.
A CFS for Markus. :)
 

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You are at a point where one can ask the question: Why not go completely into the corners?
(...)
A CFS for Markus. :)

yes, ultimately something like this:
http://www.diyaudio.com/forums/multi-way/121385-loudspeakers-room-system-32.html#post1682178

certainly putting them into lower corners guarantees no bad early reflections apart from mysterious (cause nobody knows how the hearing interprets it) ceiling reflection

This is a concept:
The enclosure is a pyramid like in my Carlssons. A 5" minibass is located in one corner of the pyramid, as close to the walls as possible. This allows corner loading up to 1 kHz. Above that a horn tweeter takes over.

Yes, interesting
though I would like to stick to 8'' Fostex one way and with it simply I don't want corner loading up to 1 kHz.
What I need is progressive augmentation of lower midrange and bass only.

best,
graaf
 
Not difficult but expensive if it has to have WAF.

what about deflecting? wouldn't it be cheaper, higher WAF and at the same time more effective (absorption is never 100%)?

Better-suited drivers will be cheaper.

cheaper perhaps but better? :)

anyway - I want to keep it simple so that anyone can do it
therefore I stick to 8'' Fostex one way
add separate tweeter and woofer and simplicity is lost
also I don't believe that really good two-way could be cheaper

best,
graaf
 
therefore I stick to 8'' Fostex one way

I have chosen the Fostex for one more important reason that is that in the case of a closed box the Fostex needs only small volume to work, and small volume plus careful choice of box proportions means less problems with the waves reflecting and standing inside

also the big magnet of Fostex serves as such as a nice standing wave breaker in a shallow box

another advantage of going omni like in CFS from the "driver-enclosure as a system" perspective is that decoupling the speakers drivers from the enclosure becomes very easy:

http://www.diyaudio.com/forums/multi-way/159731-beautiful-swingin-speaker-6.html#post2103973

best,
graaf
 
Hello,

This is kind of a strange thing.. As I see it, you like to maximize room reflections by using wide radiating monopole box, and at the same time you like to minimize room reflections by finding a placement for that box. The obtainable result is highly room dependent, surprisinlgy :D But the point is in a given room by this method you can only achieve the goal up to a certain limit.. Is that limit enough?? Does it satisfy you?? What if other method could get better end result??

For me, the most straightforward and efficient method for minimizing early room reflections is to use highly directive source. Not a monopole box! :rolleyes: Then the room placement is not so critical!


... so much for the advantages of this CFS speaker's placement option, now on to some problems
with stereo basis of ca 280 cm and the listener's distance from both speakers (the path of first wave) of ca 250 cm:
- first reflection from the floor for such short speaker is not reaching the listener at all (just like in the previous example)
- first reflection from the ceiling is delayed by ~9 ms ( (just like in the previous example)
- first reflection from the opposite wall is delayed by ~10 ms
- first reflection from the back wall is delayed by ~14 ms
...
- first reflection from the front wall is delayed only by ~2 ms
- first reflection from the side wall is delayed only by ~4 ms



I think it is up to YOU to decide if those reflections are detrimental or not for you. Afterall this is a diY audio :D What we are doing here is to do audio for ourselves, right?

Any psychoacoustic study will tell you a set of observed perceptions for a specific feature of human hearing for average population. They will not tell you how YOU perceive it! Also they will not tell you what you should like, or not like. Talking about listening room reflections it is perfectly valid for the end user to like or dislike them. It's up to you to decide.

I find it amusing when some forum members seem to thing everyone are the same and their perceptions are identical. There are not!

IF those reflections are indeed detrimental to the sound (which is not certain but let us assume that they are) then something must be done with them





- Elias
 
This is kind of a strange thing.. As I see it, you like to maximize room reflections by using wide radiating monopole box, and at the same time you like to minimize room reflections by finding a placement for that box. The obtainable result is highly room dependent, surprisinlgy :D But the point is in a given room by this method you can only achieve the goal up to a certain limit.. Is that limit enough?? Does it satisfy you?? What if other method could get better end result??

For me, the most straightforward and efficient method for minimizing early room reflections is to use highly directive source. Not a monopole box! :rolleyes: Then the room placement is not so critical!

O.K., let's surrender. This reflection thing is too hard for us.
 
This would be highend (and it is not meant positively when I use this word). Put lots of money

lots of money for 3 cm Alpha Gel cushion perhaps :) (I don't know) and I also think it would be an overkill
But what I am thinking of is rather to use some recycled air-infused Sorbothane from "SorboAir" insoles :D

in measures one hardly hears in direct A/B comparison instead of putting more money in the essential things.

well, I know that probably the effects of vibrations of speaker enclosure's walls are more or less audible for some and more or less inaudible for others, depending also on circumstances, BUT decoupling of the driver is just nice engineering idea advocated by many competent engineers including members of BBC research staff from it's classic era, Linkwitz, Yoshii-san and many others
It seems that ideally the driver and enclosure should be decoupled, though the idea is not implemented frequently because it is just not that easy to be implemented appropriately in standard front-firing box speakers.

best,
graaf
 
Hello,
As I see it, you like to maximize room reflections by using wide radiating monopole box, and at the same time you like to minimize room reflections by finding a placement for that box.

not really :) by using such a strange wide radiating monopole box I just want to have constant directivity as cheaply as possible
the truth is that such a quasi-omni is closer to the ideal than any dipole or waveguide, because all reflections on a given lateral plane are spectrally exactly the same period
such a strange box have two more big advantages over conventional front-firing alternatives from the start:
- the first is complete elimination of significant first reflection off the floor, which according to virtually all psychoacoustical studies is detrimental to realism of reproduction
- the second is sufficient delay of ceiling reflection

the only other alternative solution with which such results are achievable is true line source, Beveridge ESL for example, very costly alternative
in fact my strange boxes (I like that name :) ) were conceived as cheap practical simulation of Beveridge ESL radiation pattern :)

and then I want to have just many options with regards to audible reflections, a form of "reflections steering" by the use of careful placement and deflectors, becasue some reflections are considered bad but some other are considered quite good

so there is nothing contradictory in my approach

the point is in a given room by this method you can only achieve the goal up to a certain limit.. Is that limit enough?? Does it satisfy you?? What if other method could get better end result??

It would be great! :) but I doubt - as to "better", note that "satisfy" and "better" are two separate issues :)

and frankly speaking I am perfectly satisfied now with my mono setup and I don't care for stereo imaging/soundstaging at all :D

what I am doing here is just playing with ideas for the benefit of all who may be concerned, all dissatisfied audiophiles interested in trying something different, especially ordinary music lovers - lacking in woodworking and other technical skills, with room arrangement difficulties and other WAF concerns
therefore I want to keep it as simple and as cheap and as decor-firendly as possible

I am doing this because I am interested in audio, I have some experience with such things and I just like playing with ideas, especially when it is pro publico bono, it's just a matter of déformation professionnelle - I am an academic lecturer ;)

For me, the most straightforward and efficient method for minimizing early room reflections is to use highly directive source. Not a monopole box! :rolleyes: Then the room placement is not so critical!

"straightforward and efficient" perhaps yes but not the best, it is out of the question

to get the best You either need true line source like Beveridge ESL or strange box plus some systemic thinking about "loudspeakers and room as a system"

I think it is up to YOU to decide if those reflections are detrimental or not for you. Afterall this is a diY audio :D What we are doing here is to do audio for ourselves, right?

right 100%!! :D
Let there be no misunderstanding - all I am doing here is giving You some more choice, You will not read about things I am writing about in this thread anywhere else on the web

I find it amusing when some forum members seem to thing everyone are the same and their perceptions are identical. There are not!

I would say they are as far as everyone discussing here is biologically a specimen of the genus Homo sapiens :)

best,
graaf
 
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Yesterday I tested The Kef iQ70 in a shop. It has about the price I paid for my speakers and the Kef coaxials are said to have the most realistic imaging among the conventional speakers.

My test result is that they deliver the same "information" as my Carlssons in the horizontal plane, but not the "reach out and touch effect" and not the 3-dimensionality. One of my "hate discs" was the same catastrophy there, so probably I was too fast in my conclusion that the Carlssons are incompatible with synth reverb recordings.

Again my request for an up-to-date synth reverb recording with good imaging. Can I write decoded lossless files on CD with a freeware program? If so it would be nice if someone could send me one. If I needn't pay anything it could also be pop. :trash: