Hi everybody! today, my aunt asked me to go to circuit city to help her buy one of those expensive new-fangled "virtual" surround bars. the cheapest one we found was 1k. waaaaaaaaay too much for us. Instead of buying one, im thinking about building one using pvc as the backing and TB drivers. just a question, but is there anything special used in these? ie: weird xo, driver placement or cabinet deign?
Supposedly they do some auto-setup and bounce sound off your walls to create the surround effect. Sounds like a DSP at work:
http://www.audioholics.com/productreviews/loudspeakers/YamahaYSP-1DigitalSoundProjector1.php
http://www.audioholics.com/productreviews/loudspeakers/YamahaYSP-1DigitalSoundProjector1.php
http://www.bigpicturebigsound.com/polk-surroundbar-890.shtml
It's based on cancellation, this works fine as long as you sit exactly in the middle (for surround illusion). On stereo mode this review states you can enhance the width of the soundstage as well. (I find this dubious..).
A couple of years ago I got to test a very cute blue box from Sennheiser that did exactly the same thing, even the 'test-tone' seemed to really go 'round... But this didn't work when I listened from an uneven distance from the speakers....
It's based on cancellation, this works fine as long as you sit exactly in the middle (for surround illusion). On stereo mode this review states you can enhance the width of the soundstage as well. (I find this dubious..).
A couple of years ago I got to test a very cute blue box from Sennheiser that did exactly the same thing, even the 'test-tone' seemed to really go 'round... But this didn't work when I listened from an uneven distance from the speakers....
I think that Polk one works very differently to the Yamaha. The Yamaha really does make sound come from behind you if I remember correctly (haven’t read that huge long review).
I seem to remember that the Yamaha one works by ultrasonic pulsing. If you take two tones (can be any frequency, but they need to have the correct relationship to each other) and sum them, there will be a lower frequency tone created as a result of the phase relationships. So, the Yamaha uses ultrasonic sounds which overlap in this way at a position which is behind you, thus the lower (audible) sound actually does come from behind you, even if the inaudible ultrasonic sounds come from the speaker in front.
Now I may well have some of that ar5e about face but I am pretty sure that’s the basic theory behind it.
I seem to remember that the Yamaha one works by ultrasonic pulsing. If you take two tones (can be any frequency, but they need to have the correct relationship to each other) and sum them, there will be a lower frequency tone created as a result of the phase relationships. So, the Yamaha uses ultrasonic sounds which overlap in this way at a position which is behind you, thus the lower (audible) sound actually does come from behind you, even if the inaudible ultrasonic sounds come from the speaker in front.
Now I may well have some of that ar5e about face but I am pretty sure that’s the basic theory behind it.
AAAhhh finally found it on the net:
http://www.stereovideo.cz/old/9907/profil2.html
http://buy.sennheiserusa.com/ASP/Sennheiser/HiRes/dsp360.jpg
It's not the latest technology, so I don't know if the newer processors are more capable. I didn't find it really impressive, but if you insist on surround and don't want speakers to crowd your room it can be a solution.
http://www.stereovideo.cz/old/9907/profil2.html
http://buy.sennheiserusa.com/ASP/Sennheiser/HiRes/dsp360.jpg
It's not the latest technology, so I don't know if the newer processors are more capable. I didn't find it really impressive, but if you insist on surround and don't want speakers to crowd your room it can be a solution.
The sound will become a lot more surround when you shift the phase a littlebit on one channel..
But I had the opportunity to buy the dsp-360 from Sennheiser for 30 EUR. and this device can be most usefull for your project. The rest would be the TB's, a cabinet and amps....just check Ebay....
But I had the opportunity to buy the dsp-360 from Sennheiser for 30 EUR. and this device can be most usefull for your project. The rest would be the TB's, a cabinet and amps....just check Ebay....
OK Legendaryfrog. I asume from earlier posts, you are on a restricted budget. We've all been there! IMHO it's best to get 2 of the best quality drivers you can. If you split those funds 4 ways, the quality drops of faster than that gained from using multiple drivers.
This is one budget way of increasing the spatial effect, if that is what your after. Open with word pad.
All drivers identical and equally spaced. the 2 2nd in from the ends want to
be 30 degrees of centre. The output from the source just stereo.
A basic 2.1 computer style mm system may be better for the money.
I bought an ACS45 a short while back fo $20 + freight.
Edit. windoze upset the formatting.... on the attachment. If you have probs I'll do a better pic later.
Geoff
This is one budget way of increasing the spatial effect, if that is what your after. Open with word pad.
All drivers identical and equally spaced. the 2 2nd in from the ends want to
be 30 degrees of centre. The output from the source just stereo.
A basic 2.1 computer style mm system may be better for the money.
I bought an ACS45 a short while back fo $20 + freight.
Edit. windoze upset the formatting.... on the attachment. If you have probs I'll do a better pic later.
Geoff
Polk looks to be an old idea based on "stereo dimensional array":
http://www.polksda.com/
It seems fairly rudimentary and a novice DIY could probably pull it off with similar results as Polk. On the other hand, the Yamaha is a bit more complicated.
http://www.yamaha.co.jp/english/product/av/pdfs/moreinfo/ysp1100.pdf
The Yamaha is based on a fairly sophisticated Reinforcement-interference type of steering (sort of like multiple Bessel arrays that are individually controlled) using a multitude of drivers each individually driven by its own amplifier all controlled by the signal processor (YSP 1100 would have 2 - 5" woofers and 40 widerange drivers and 42 amplifiers!) Definitely not an easy DIY project.
These guys hold the patent (and sell the processor):
http://www.1limited.com/tech/silicon/sound.html
http://www.polksda.com/
It seems fairly rudimentary and a novice DIY could probably pull it off with similar results as Polk. On the other hand, the Yamaha is a bit more complicated.
http://www.yamaha.co.jp/english/product/av/pdfs/moreinfo/ysp1100.pdf
The Yamaha is based on a fairly sophisticated Reinforcement-interference type of steering (sort of like multiple Bessel arrays that are individually controlled) using a multitude of drivers each individually driven by its own amplifier all controlled by the signal processor (YSP 1100 would have 2 - 5" woofers and 40 widerange drivers and 42 amplifiers!) Definitely not an easy DIY project.
These guys hold the patent (and sell the processor):
http://www.1limited.com/tech/silicon/sound.html
legendaryfrog said:
Hi,
You need lots of small drivers, lots of active amplifiers, lots of DSP.
They work by phase array steering, nothing to do with ultrasonics.
For a one box under the plasma solution they are the only option.
Sound quality per dollar will not compete with the usual speaker array.
/sreten.edit :
The Polk is based on stereo principles made famous by Hafler, there
is nothing particularly new fangled about it, except multi-channel drive.
Re: Re: One bar surround
I'm sure something did! lol! I would have said sound steering only I'm sure I read something about it working by pulsing. *scratches beard*
sreten said:
Hi,
You need lots of small drivers, lots of active amplifiers, lots of DSP.
They work by phase array steering, nothing to do with ultrasonics.
I'm sure something did! lol! I would have said sound steering only I'm sure I read something about it working by pulsing. *scratches beard*
V-Bro, you are spot on. If I get time later today, I'll post a drawing.
It's nothing complex. Start with the standard 2 chan setup.
2 speakers connected in series, with the -ve sides common, yes, out of phase, are connected between the +ve teminals on the amp.
That is a basic quad setup. If the rear level is too high, a 50ohm w/w pot can be inserted between the rear set.
Now, the rear set can be moved to the sides, or outside front, to give a bigger sound stage.
A 5th driver can be added as a centre. It is connected between the junction of the 2nd pair, and common.
So the signals to each speaker, starting at the left are:
0.5(L- R) L 0.5 (L+R) R 0.5(R-L)
No DSP, no time delay, just phasing and level adjustment.
However, I still believe in this situation, it would be best to put the money into 2 drivers, not 4 or 5.
It's a bit like tinny speaker x 2 = 2 tinny speakers, or 2x$25 drivers compared to 5x$10 drivers.
DIY should be about getting better value for money, not just saving it.
Geoff.
It's nothing complex. Start with the standard 2 chan setup.
2 speakers connected in series, with the -ve sides common, yes, out of phase, are connected between the +ve teminals on the amp.
That is a basic quad setup. If the rear level is too high, a 50ohm w/w pot can be inserted between the rear set.
Now, the rear set can be moved to the sides, or outside front, to give a bigger sound stage.
A 5th driver can be added as a centre. It is connected between the junction of the 2nd pair, and common.
So the signals to each speaker, starting at the left are:
0.5(L- R) L 0.5 (L+R) R 0.5(R-L)
No DSP, no time delay, just phasing and level adjustment.
However, I still believe in this situation, it would be best to put the money into 2 drivers, not 4 or 5.
It's a bit like tinny speaker x 2 = 2 tinny speakers, or 2x$25 drivers compared to 5x$10 drivers.
DIY should be about getting better value for money, not just saving it.
Geoff.
hi again! today i contacted polk, and they explain the technology behind the surroundbar. they said that the speaker drivers are in this order:
L. front>R surround>Center>L surround>R front
the technology behind it is basically nothing. while the inside has some special ports that make the displaced air from the fronts go farther than the rear speakers displaced air.
Edit: the drivers are ear length apart, and the driver cones are weighed down on one side.
L. front>R surround>Center>L surround>R front
the technology behind it is basically nothing. while the inside has some special ports that make the displaced air from the fronts go farther than the rear speakers displaced air.
Edit: the drivers are ear length apart, and the driver cones are weighed down on one side.
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