CLS I have played with exciters quite a bit and so some thoughts. I have found cardboard to sound much better than foam core. (more natural) A sheet with the corrigations vertical could be bent so that 2 exciters face the side walls. A lot of sound comes from the exciters themselves particularly higher frequency. The bends also tend to limit vibration to the section of panel panel each exciter is on. Another benefit, it will stand up on it's own. I usually just attach the exciters with 3M VHB tape.I think that such an arrangement would be closer to what Elias has shown to work.
Update !
New elements for another prototype: CHR-70
On wall SSSx5
More updates:
Elias Pekonen Home Page - Stereophonic Sound from a Single Speaker
- Elias
New elements for another prototype: CHR-70
An externally hosted image should be here but it was not working when we last tested it.
On wall SSSx5
An externally hosted image should be here but it was not working when we last tested it.
More updates:
Elias Pekonen Home Page - Stereophonic Sound from a Single Speaker
- Elias
SSSx5 directivity plots !
Center panned stereo signal:
Side panned stereo signal:
Read the comments from here:
http://dl.dropbox.com/u/2400456/html/Elias_Pekonen/SingleSpeakerStereo.html
- Elias
Center panned stereo signal:
An externally hosted image should be here but it was not working when we last tested it.
Side panned stereo signal:
An externally hosted image should be here but it was not working when we last tested it.
Read the comments from here:
http://dl.dropbox.com/u/2400456/html/Elias_Pekonen/SingleSpeakerStereo.html
- Elias
Last edited:
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Nice one Elias.... Mine is same drivers smaller box (not by much) and mounted behind TV exactly like yours!!!! Copy Cat!
I use a 8uf cap and 4.7ohm resistor. Can you do a sim for these? i doubled the cap value because the CHR-70 are 4 ohm. Sounds good. But would love to see the sim.
Cheers,
Optic
I use a 8uf cap and 4.7ohm resistor. Can you do a sim for these? i doubled the cap value because the CHR-70 are 4 ohm. Sounds good. But would love to see the sim.
Cheers,
Optic
@CLS: Like Jim G, I too have observed that corrugated cardboard sounds 'crisper' -- but only when it is from a quality maker and also when it hasnt absorbed any moisture. High humidity throws everything out of kilter.
Double-sided tape for attaching exciters is "quick and dirty", but I guess better results could be had when they are glued on with a thin coat of 'bone-dry'-setting adhesive like Araldite (two-part epoxy), the caveat being that getting the exciter off means cutting out a section of card, then carefully moistening and getting off the card and then scraping some! Also, a supporting bridge for the exciter back is known to cut down sound from it.
Realizing the SSS a-la Elias would be something with panels! Happy DIYing!
Double-sided tape for attaching exciters is "quick and dirty", but I guess better results could be had when they are glued on with a thin coat of 'bone-dry'-setting adhesive like Araldite (two-part epoxy), the caveat being that getting the exciter off means cutting out a section of card, then carefully moistening and getting off the card and then scraping some! Also, a supporting bridge for the exciter back is known to cut down sound from it.
Realizing the SSS a-la Elias would be something with panels! Happy DIYing!
Those measurements were done inside at 1 m distance so at least floor reflection is present, thus some wringles in the response.
The hole at 60 deg 3 kHz is practically not inportant considering it is located in the bottom of a valley separating direct sound from side sound.
The important thing to see is to notice directivity pattern steering according to stereo signal !
Above 10kHz CHR70 gets narrow, but on the other hand I don't know any full range which dont. It is interesting however that this also don't seem to matter very much, maybe because this concept has elements at all three sides, and thus 'power response' is smoother than usually with full ranges.
- Elias
Nice one Elias.... Mine is same drivers smaller box (not by much) and mounted behind TV exactly like yours!!!! Copy Cat!
I use a 8uf cap and 4.7ohm resistor. Can you do a sim for these? i doubled the cap value because the CHR-70 are 4 ohm. Sounds good. But would love to see the sim.
Cheers,
Optic
We want pics !
For the psychoacoustic filter, a rule of thumb could be:
For a 8 ohm elements use R = 4.7, and for a 4 ohm elements use R = 2.2. C value depends what freq band you like to alter.
With CHR-70 I used R = 2.2 ohm and C = 6.8 uF.
- Elias
Stereosphere is alive!
Now powered by SSSx5 technology:
Listening impressions in comparison to 2 speaker stereophony:
- increased depth
- no spatial/spectral "disturbance" when turning head
- virtually no stereo effect, all sounds emanating from the center
- somewhat diffuse but not unnatural sound stage
- localization of high frequency content at speaker location
An externally hosted image should be here but it was not working when we last tested it.
Now powered by SSSx5 technology:
An externally hosted image should be here but it was not working when we last tested it.
Listening impressions in comparison to 2 speaker stereophony:
- increased depth
- no spatial/spectral "disturbance" when turning head
- virtually no stereo effect, all sounds emanating from the center
- somewhat diffuse but not unnatural sound stage
- localization of high frequency content at speaker location
I have wondered what a pair of Bose 901's stacked on top of each other and rewired left and right accordingly driven by a HT receiver and the two front drivers on the center channel would sound like. Is this the same effect? I read most of this thread and tried to follow the discussion.
I would install this inside of a Vintage upright console radio.
I would install this inside of a Vintage upright console radio.
Are you using the RC filter/attenuator circuit? It works - adjustable to suit your room. larger cap &/or resistor --> more lateral spread, less center.
If still getting too much from center when taken to the extreme (center bypassed), then SSS won't work in your room . . . If sidewalls are too distant, too absorbent, or too asymetrical, the precedence effect will dominate no matter what adjustments are made.
-- Mark
Fixer,
One can't really say if it would be "the same effect", but I doubt it. Any Dolby etc processing is considerably different than passive processing. 'Could work well, but would not be the same as SSS.
Problems:
1) Center drivers would have to be removed from the cabs & pointed at listener. Won't work pointing to the sides.
2) A Substantial impedance mismatch would result: The Bose 901 drivers are only 1 ohm impedance each. Your sides would be 7 ohms and the center only 2 ohm (or worse yet 0.5 ohm in parallel). Very heavy-handed level adjustment will be required. The low impedance could also damage your amplifier.
You could use a third 901 cab for the center speaker. This is the most workable solution. The active EQ required for the 901 makes using any other drivers a bad idea, surrounds included. I also have no idea how you could incorporate the Active EQ into a HT unit, unless it is an older AVR with a tape monitor loop, or if you have only one input source.
you'd be kinda missing the point of SSS by dealing with all of this as described. The primary charm of SSS is one-box simplicity, and compatability with any monaural or 2 channel recordings, on any 2-channel stereo system (except for amps that do not share ground).
-- Mark
My mom would love this. She thinks my dad and i are silly for all the attention we put into speaker placement in the room. She would prefer that things like speakers and cables are out of site, while we believe that bringing speakers out away from yhe walls reduces early reflections and improves the stereo image.
I cant help but be reminded of a friend in college that took a pair of Infinity small bookshelfs and put them back to back behind his TV, it actually sounded very good and created a very wide sound-stage.
I cant help but be reminded of a friend in college that took a pair of Infinity small bookshelfs and put them back to back behind his TV, it actually sounded very good and created a very wide sound-stage.
You have shrinked the SSS
Look at the size of the screw terminals compared to the box ! I assume all famous FRS8.I have few suspections of why 'no stereo effect' in your observation.
1) Your listening distance may be too small ! What is the listening distance in relation to the room width? Earlier I found there is a minimum distance that should be satisfied in order to stereo to work. As posted earlier, for optimum results: listening distance > room width.
An externally hosted image should be here but it was not working when we last tested it.
2) Your box may be too small ! (sorry to calumniate your fine design
) In a too small of a box, there is no 'baffle gained directivity' in the midrange. In any linear three speaker matrix the maximum separation is 6dB between the three channels (only when x = 0.5). This can be achieved if the acoustic signal do not 'leak' to the wrong side which allways happends and only depends on frequency and the size of the box (diffraction).3) You may not have installed the psychoacoustic filter ! It helps to hide the speaker, by directing the energy from the center to the sides. As Tubamark noted it can be adjusted depending on your side wall reflectivity.
4) Is your front wall (behind the speaker) absorbed ? I don't know if this is a benefit or not, but I have a feeling that absorbing the front wall kills a portion of the side energy as well (front wall -> side wall reflection).
As the perception is mainly based on mudulation envelope, and modulation envelope in music changes relatively slowly compared to the time difference of reflections in a typical small room so more side reflections also increases side energy which helps in 'imaging' to keep the image at the correct side.
5) Poor (studio) recording, including no or negligible of ambiance. Remember, mono should be at the center
Despite of these obstacles I have observed also the same:
The depth is deeper than conventinal stereo triangle. As a complete opposite to stereo triangle, SSS is immune to head rotation.
Speech intelligibility ?
- Elias
By the way, here's my latest of SSSx5 with Mark Audio Alpair5
The size of the side panels are 40*34cm. Front panel is 40*20cm. It's bigger than the earlier prototype, and volume is bigger than would be required by the elements, but the purpose was to examine the effect of increased side separation.
It sounds good
- Elias
An externally hosted image should be here but it was not working when we last tested it.
The size of the side panels are 40*34cm. Front panel is 40*20cm. It's bigger than the earlier prototype, and volume is bigger than would be required by the elements, but the purpose was to examine the effect of increased side separation.
It sounds good
- Elias
To address the potential problem of tonal balance of the negative vector dipole effect if left uncompensated, now there is a solution !
The signals for the three elements of the SSS are as before:
Lo = L - xR
Ro = R - xL
Co = xL + xR
where parameter x is between:
x = 0...1
Rearranging the terms:
L - xR = (1 - x)L + x(L - R)
R - xL = (1 - x)R + x(R - L)
xL + xR = x(L + R)
And utilising definition of MS stereo:
M = L + R
S = L - R
The three element signals of the SSS can be written as:
Lo = (1 - x)L + xS
Ro = (1 - x)R - xS
Co = xM
Heureka !
Because L and R remain in same phase in typical mixing practises, the only term causing negative vector is the S signal. S signal forms a sideways dipole in the SSS. This can be compensated easily ! I've drawn one possible configuration below:
Stereo signal is fed into MS matrix to form M and S signals. Then dipole correction is applied to S signal, and compensatory phase correction is applied to M signal. Then using inverse MS matrix signal is transformed back to L and R format which is fed into SSS speaker.
An externally hosted image should be here but it was not working when we last tested it.
This is expected to correct any possible issues in frequency dependent tonal balance depending on input signals
- Elias
Looks like I was not shooting in the dark about the MS matrix equaliser, but reinventing the wheel !
Applications of Blumlein Shuffling to Stereo Microphone Techniques
Gerzon, JAES 1994
http://decoy.iki.fi/dsound/ambisonic/motherlode/data/6939.pdf
Also another document:
Studio Sound, July 1986
Stereo Shuffling: New Approach – Old Technique
http://www.audiosignal.co.uk/Resources/Stereo_shuffling_A4.pdf
I did not try it yet to the SSSx5, simply because I haven't noticed such obvious flawes which would need compensation.
In theory it could improve low frequency stereo effects.
Thanks to Blumlein and Gerzon, stereo reproduction has become very interesting
- Elias
