Hi Scott
While my L and R subwoofers aren't towers exactly, they do do the business as side walls.
I have employed the Elias pschoacoustic filter of a resistor and cap, and that work pretty well. Have messed with cap values and found one that works, not yet with resistor values.
Like your comments about an upfiring tweeter because the B200s I've found always need a bit of top end reinforcement. Will consider that in time. Just not sure where it would go in the circuit.
While my L and R subwoofers aren't towers exactly, they do do the business as side walls.
I have employed the Elias pschoacoustic filter of a resistor and cap, and that work pretty well. Have messed with cap values and found one that works, not yet with resistor values.
Like your comments about an upfiring tweeter because the B200s I've found always need a bit of top end reinforcement. Will consider that in time. Just not sure where it would go in the circuit.
The center's low-pass filter that Elias has further down on his web page are rather high in freq. and not as "steep" as it might be preferred.
Additionally, the overall intensity from the *sides* is also to high in spl relative to the center. (..the direct sound, NOT the reflected sound - which we want to be higher in level.)
Finally, the intensity gradient isn't "broken" because of the center (..and even if it were, the sides aren't either below about 1.7 kHz for a small fullrange driver). (..refer back to Elias's experiments with a seat cushion in front of the loudspeaker.)
1. you want a "broken" gradient (..that a side-mounted waveguide can provide where the center's output is strongly low-passed),
2. you want to be able to adjust the spl of the side's (above 1.7 kHz) freq. response to get a linear presentation (..or higher spl from those "side-wall" reflections).
Additionally, the overall intensity from the *sides* is also to high in spl relative to the center. (..the direct sound, NOT the reflected sound - which we want to be higher in level.)
Finally, the intensity gradient isn't "broken" because of the center (..and even if it were, the sides aren't either below about 1.7 kHz for a small fullrange driver). (..refer back to Elias's experiments with a seat cushion in front of the loudspeaker.)
1. you want a "broken" gradient (..that a side-mounted waveguide can provide where the center's output is strongly low-passed),
2. you want to be able to adjust the spl of the side's (above 1.7 kHz) freq. response to get a linear presentation (..or higher spl from those "side-wall" reflections).
If the stereo amplifier has common output terminals they should be already internally in galvanic contact.
For 6 ohm elements the matrix gives 9 (= 6 + 6/2) ohms impedance for each amplifier. The R-C filter lowers the impedance at high freqs to 6 ohms (in this case).
Yes the matrix needs a common terminal from the amplifier.
A bridged output amplifier does not yield the intended results, because it does not have the common terminal.
Common means in EE terms having same potential i.e. the voltage between the two common terminals is allways zero.
Glad to hear you got it working well for your purpose
Your comments about the sound I feel are exactly as mine too. No sweet spot, Imaging in the whole room, and the filter is mandatory (though it may depend on the side walls distance and their reflectivity capabilities)
Now that is a heavy argument
I'm sure there is plenty of room for experimentation for the filter values
Basically the required response depends on multiple of things, among others:
- Distance to the side walls
- Reflectivity of the side walls at high freqs
- Directivity pattern of the drivers
Since rooms are different, and because one may use any driver one wishes, there cannot be one universal filter that fits all the situations.
You may be referring to a 'leakage' of the sound from the side drivers to the listening position.
It is only a potential problem at high freqs where the distance between drivers is getting too long relative to wavelength for proper vector steering to be formed. The solution is easy and can be handled by increasing the directivity of the side drivers.
Do you think anyone understands you "broken gradient" theory ?
If you refer to lobing, yes lobing is intentional and occurs in the whole freq band.
At low freqs the main lobe is steered by the incoming stereo signal and the lobe points to the direction of the highest amplitude panning. This is the whole purpose of the matrix.
At high freqs the lobing occurs due to drivers behaving more individually rather than by vector summing means. Still the matrix gives amplitude separation of 6 dB to the direction of the amplitude panned signal.
That's why this speaker generates stereo images in the room in the first place
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I'm enjoying the sound from the SSS system, still messing with psychoacoustic filter values. They have quite an appreciable effect.
I have always used tweets of some kind with the B200s. I am wondering how to implement auxiliary tweets or even just one in this circuit? If feasible electrically in which direction should this point?
This system is really a bunch of fun. I like that it SO goes against the grain and freaks out people who believe a pair of speakers is an absolute necessity for enjoyable two channel music reproduction. The SSS is way liberating.
I have always used tweets of some kind with the B200s. I am wondering how to implement auxiliary tweets or even just one in this circuit? If feasible electrically in which direction should this point?
This system is really a bunch of fun. I like that it SO goes against the grain and freaks out people who believe a pair of speakers is an absolute necessity for enjoyable two channel music reproduction. The SSS is way liberating.
So I have been messing around with cap and resistor values for the SSS psychoacoustic filter and last night hit the jackpot at last. The cap/resistor values for the B200s are not so very different from those Elias suggested, though I only saw those after the fact. But last night, for the first time, the image became locked in above the speaker. It is really very much like an image you'd get with two-channel stereo, except that it doesnt matter so much where you're located or whether you head is tilted or which way the wind is blowing. In other words, the image stability is tops, and unchanging.
For those who haven't tried this system, it's definitely worth a shot because it is so easy to build. I had three B200s lying around, and a host of caps and resistors and wire. A basic build took only a couple of hours. Im not saying Im never returning to two speakers, but it will be interesting going back and comparing. Im just not prepared to do that right now.
For those who haven't tried this system, it's definitely worth a shot because it is so easy to build. I had three B200s lying around, and a host of caps and resistors and wire. A basic build took only a couple of hours. Im not saying Im never returning to two speakers, but it will be interesting going back and comparing. Im just not prepared to do that right now.
Attachments
Do you think anyone understands you "broken gradient" theory ?
Physical Gradient: *direct* sound intensity as it decreases from source/loudspeaker over distance (and to listener).
Put something in the "path" between that source/loudspeaker (relative to freq.), and it becomes "broken".
You know, like a couch pillow in front of the loudspeaker - between the loudspeaker and the listener.
If you put a tweeter/compression driver in a waveguide that's at 90 degrees from the listener (i.e. "side-firing"), then for higher freq.s the gradient is effectively "broken" - it no longer has a direct path to the listener.
Generally, (depending on wavelength), if you can't see the source then the gradient is "broken".
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Hi Scott
Can you please explain what you mean in a practical sense?
Are you suggesting that I should add a pair of tweeters firing out through waveguides to the side firing B200s and then the psychoacoustic filter isn't required?
Im interested to assess the effect of adding a tweeter (or two) to the system but earlier posts seem to suggest otherwise.
Can you please explain what you mean in a practical sense?
Are you suggesting that I should add a pair of tweeters firing out through waveguides to the side firing B200s and then the psychoacoustic filter isn't required?
Im interested to assess the effect of adding a tweeter (or two) to the system but earlier posts seem to suggest otherwise.
Yes, that was an early image taken during the initial build.
The subs now stand about 15 inches away from the SSS. However, I have only just gotten the imaging to lock in properly so haven't played with moving the subs right away from the speaker system entirely. Will give that a shot over the next few days.
The subs now stand about 15 inches away from the SSS. However, I have only just gotten the imaging to lock in properly so haven't played with moving the subs right away from the speaker system entirely. Will give that a shot over the next few days.
- practical sense?
To an extent side-drivers already do this (assuming you aren't listening far off-axis from the front of the loudspeaker). The larger the driver the lower in freq. it will do this, so the B200's are already doing this a bit below 2kHz. (..which is about right). And in fact the B200's are particularly directive.
The B200's directivity plot:
B 200 - 6 Ohm
At 90 degrees it's showing more than 10 db of loss for the 2 kHz plot. Even 45 degrees is about 7 db of loss - which is a heck of a lot better for this application than a smaller driver (..or simply one that is less directive at higher freq.s).
*Do NOT add a tweeter to this driver.
(..or at least not one that operates below about 8 kHz at any intensity near the average.)The low-pass or "shelving-filter" will be critical for the *frontal* B200.
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If considering a "convetional" soundbar, would it be possible for the side drivers be angled 45 degrees forward? I have bunch of Vifa TC19FD-18-08's and I might make a mock up cabinet to test this concept. I read the articles in Elias's homepage and is the basic concept really as easy as wiring the speakers as described, without any processing or filters (except Psychoacoustic filter)?
Side drivers can be tilted forward, but have to consider why to do it ? Too much of tilting causes side driver signals to leak directly to the listening position, which is not desirable. Small drivers as 3-4" may not benefit of the tiliting. Bigger drivers 8" and up, tilting may be a good idea.
Yes, the passive matrix is all that is needed. Simple things can work too
- Elias
Sorry for replaying to some very old question in an old topic, but... what about trying something like a "Blumlein Pair" ... "reversed"?
That is, a pair of open baffles (which are "figure 8" speakers...) positioned 90° from each other?
(think the two open-baffle panels arranged in something like figure "T" or "X")
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Heh heh. Funny how statements like that can make a liar out of you.
Im now using the B200s in sealed boxes, only the boxes are cylinders. Still needing to tame the tops with a filter but I don't believe the B200s have sounded as good OB. There's a hint of bass emphasis that I can live with. Cylinders look pretty ordinary but they're much easier to get rigid than any box. The endcap with the terminal cap is the weak link. Not sure how to tame the resonances there, but the cylinder is utterly non-resonant when you put an ear up to it.
Anyhow, getting off topic here. When I was playing with the SSS I was constantly astounded by how little it interacted with the room - it sounded the same no matter where you stood, and in any room, but people kept saying it's a waste of time, it don't image properly.
And now look at how many Bluetooth/streaming devices are just single speaker stereo systems. The best of which, by all accounts (I've not heard it but others rave) is Naim's Mu-so. None I've tried seems to interact so minimally with the room however as the SSS. People like that amps and speakers are all inside one box, and being able to access electronics wirelessly is a plus for most too. Plus you can slap the single speaker anywhere you want. Only dont expect any imaging per se. I miss that, and keep returning to a stereo pair as a result. Which may be blasphemy here.
Im now using the B200s in sealed boxes, only the boxes are cylinders. Still needing to tame the tops with a filter but I don't believe the B200s have sounded as good OB. There's a hint of bass emphasis that I can live with. Cylinders look pretty ordinary but they're much easier to get rigid than any box. The endcap with the terminal cap is the weak link. Not sure how to tame the resonances there, but the cylinder is utterly non-resonant when you put an ear up to it.
Anyhow, getting off topic here. When I was playing with the SSS I was constantly astounded by how little it interacted with the room - it sounded the same no matter where you stood, and in any room, but people kept saying it's a waste of time, it don't image properly.
And now look at how many Bluetooth/streaming devices are just single speaker stereo systems. The best of which, by all accounts (I've not heard it but others rave) is Naim's Mu-so. None I've tried seems to interact so minimally with the room however as the SSS. People like that amps and speakers are all inside one box, and being able to access electronics wirelessly is a plus for most too. Plus you can slap the single speaker anywhere you want. Only dont expect any imaging per se. I miss that, and keep returning to a stereo pair as a result. Which may be blasphemy here.
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