Now that I've got a 42 inch HD TV between my tri-amp'd open baffle speakers, I have a place for a center speaker (under the TV), which I'm in the process of building. The question is what to feed it (?). How to make it a plus rather than a minus. Apparently this is a difficult question, so I'm hoping for some good suggestions.
So far it sounds like it's the upper midrange and low treble that could benefit from it, due to comb filtering from the 2 regular speakers in that frequency range. Perhaps a frequency selective L-XR function that attenuates those frequencies from the L and R speakers by maybe 3dB, and a complimentary L+R for the center speaker? Outside of that upper mid/low treble frequency range, it sounds like the center speaker does more damage to the sense of width than good. Although, below 100HZ, a center speaker could help fill in room acoustics problems that cause bass to be a bit boomy. Comments are encouraged.
So far it sounds like it's the upper midrange and low treble that could benefit from it, due to comb filtering from the 2 regular speakers in that frequency range. Perhaps a frequency selective L-XR function that attenuates those frequencies from the L and R speakers by maybe 3dB, and a complimentary L+R for the center speaker? Outside of that upper mid/low treble frequency range, it sounds like the center speaker does more damage to the sense of width than good. Although, below 100HZ, a center speaker could help fill in room acoustics problems that cause bass to be a bit boomy. Comments are encouraged.
Yeah, on several CC threads I've noted that limiting the CC to one designed for high speech intelligibility is desirable, especially for us older folks who can have a hard time with some dialog tracks, which is also the original motion picture playback curve AFAIK, i.e. flat from ~125 - 2500 Hz, rolling off 6 dB/octave down low and 3 dB/octave up high, though with an 80 - 120 Hz HT XO spec, we can of course 'fudge' the low end requirement.
Unfortunately though, supposedly there's been a shift by some to concentrate the bulk of the front stage into the CC with the L/R channels reduced to 'fill'/pan effects, so we may ideally need to have two response curves for the CC.
GM
Unfortunately though, supposedly there's been a shift by some to concentrate the bulk of the front stage into the CC with the L/R channels reduced to 'fill'/pan effects, so we may ideally need to have two response curves for the CC.
GM
This year I have rebuilt my multichannel active speaker system and I have implemented Gerzon’s Trifield matrix (2-to-3 channel Optimal Reproduction Matrix for Multispeaker Stereo).
It may seem complex, but thanks to DSP the implementation was quite easy. It has several important features:
- Energy preservation (sound energy radiated by three L,C,R speakers is always equal to the sound energy of stereo L,R channels)
- Frequency-dependence (high frequencies are attenuated in the C channel and gained in the L and R channels)
- Trifield coefficients live adjustments
- C channel delay and gain setup (according to C speaker position)
- Trifield matrix effective above 200 Hz (stereo multi-woofer below 200 Hz)
The Trifield decoder result is excellent. I can instantly compare the Trifield mode to normal stereo mode. For some kinds of music (piano, orchestral) with no strong central sounds the difference is not huge. However when there is strong sound in the middle of the scene (vocal, solo instruments) the effect is obvious: no colored sound caused by the comb filtering, better focused sound and better stage distance perception (surprisingly central sounds usually don’t seem to be closer).
The Trifield implementation is described here.
It is still one person experience. The lateral sweet spot is noticeably wider, but one have to watch also the proper distance to the speakers (and the proper C channel delay).
An externally hosted image should be here but it was not working when we last tested it.
It may seem complex, but thanks to DSP the implementation was quite easy. It has several important features:
- Energy preservation (sound energy radiated by three L,C,R speakers is always equal to the sound energy of stereo L,R channels)
- Frequency-dependence (high frequencies are attenuated in the C channel and gained in the L and R channels)
- Trifield coefficients live adjustments
- C channel delay and gain setup (according to C speaker position)
- Trifield matrix effective above 200 Hz (stereo multi-woofer below 200 Hz)
The Trifield decoder result is excellent. I can instantly compare the Trifield mode to normal stereo mode. For some kinds of music (piano, orchestral) with no strong central sounds the difference is not huge. However when there is strong sound in the middle of the scene (vocal, solo instruments) the effect is obvious: no colored sound caused by the comb filtering, better focused sound and better stage distance perception (surprisingly central sounds usually don’t seem to be closer).
The Trifield implementation is described here.
It is still one person experience. The lateral sweet spot is noticeably wider, but one have to watch also the proper distance to the speakers (and the proper C channel delay).
I'm messing with synthesizing a center channel in my car. I am using prologic II. Mostly because it's the brainchild of Jim Fosgate, and well regarded.
It's difficult to get a PLII output without using a htpc. The way that I'm doing it is by using a decoder that was actually intended for videogames, called a "Tritton AxPro." They're about $10 on eBay.
Besides saving myself the complexity of building a htpc, the AxPro also allows me to do time delay and xover with minidsp.
Everything's documented over at diyma in a thread titled "five channel soundstage"
Actually this is a plain DIY project for my living room main audio system. I doubt there would be any sufficient interest in obtaining such a kit. However I recommend to try Trifield system to anyone that can apply DSP processing. I have shown that the implementation is not complex and there are a lot of flexible adjustments possible.Seems like a nice approachI couldn't find a price on his www for the software or kit etc ?
sorry for bumping.
unfortunatly the image is gone, and the links are dead.
I would love to implement a trifield setup with DSP on my computer, but I can't find out how
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This is not exactly what you ask for but a similar thing, hope it helps in case you don't find the info. Can be implemented and in DSP why not.
http://elias.altervista.org/html/SingleSpeakerStereo.html
http://elias.altervista.org/html/SingleSpeakerStereo.html