Mid Side Speakers
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URL: https://forum.speakerplans.com/forum_posts.asp?TID=73892
Printed Date: 19 April 2024 at 6:53pm
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Topic: Mid Side Speakers
Posted By: Abe The Babe
Subject: Mid Side Speakers
Date Posted: 24 November 2012 at 5:56pm
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I made a comment two days ago about designing a mid side speaker array. I have put a lot more thought into this since the comment and I'm not sure how it can actually make sounds appear left or right as the time of arrival differences would be next to non existant (which is part of the idea) and I don't understand how you recieve the guitar for example at a higher level at one ear than the other. It does make sense though that by altering the amount of a sound in the side speakers the image can be made wider, or further away, maybe general area left or right based on the reflections from the left side of the room vs right side, but if that were the case the more you tried to make an instrument appear left or right the further away the sound would appear.
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Replies:
Posted By: thepersonunknown
Date Posted: 24 November 2012 at 7:27pm
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have you got a link to the thread u mentioned? im not familiar with this mid side technique. do you refer to a left center right deployment? if i understand you correctly about how the brain interprits the direction sound is comming from, i believe it is similar to triangulation (like what the gprs networks do to locate your position) it is quite amazing realy, but perhaps not so much as the eyes ability to judge distance through a similar method, given the light is sooo much faster than sound and the differences in arival time are even more minute. i was sitting the other day listening to dogs barking in the distance and marveling that my ears and brain were able to tringulate the direction over a distance of perhaps 1km, even though my ears are only 20co or so apart. sorry if i have missed the point there cheers dave ------------- They keep telling me life is short, but its the longest thing ive ever done!!! |
Posted By: Abe The Babe
Date Posted: 24 November 2012 at 8:44pm
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http://forum.speakerplans.com/constant-dispersion-2khz-15khz-point-source_topic72566_page4.html Mid Side is normally a stereo mic'ing technique, using a directional mic and a mic with a fig. 8 polar pattern. The directional mic is pointed at the source, this provides the direct sound and the centre of the stereo image. The fig 8. is placed perpendicular to the directional mic with their diaghrams coincident, this is referred to as the side mic. The signals from the 2 mic's are run into a mixer (or daw). The mid mic is unpanned sending equal polarity and level to both speakers. The side mic is sent to two individual channels, they are hard panned left and right and one of the channels is polarity reversed the faders are grouped. When the signals are summed acoustically after leaving a conventional left right speaker system the stereo image is created by the interaction between the three signals.
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Posted By: Abe The Babe
Date Posted: 24 November 2012 at 10:07pm
| http://www.artofrecordproduction.com/index2.php?option=com_content&do_pdf=1&id=224 I just found this. Explains a bit, still an interesting idea. |
Posted By: thepersonunknown
Date Posted: 25 November 2012 at 12:18am
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right. thanks for clarifying. i cant imagine that method of miking being much more than a source of feedback on a live stage, but i must say ive never tried. as a matter of fact this is the first time i hear of the technique. ive not had time to check out that link above, but ill have i peek later. i must say im a little scheptical of it being used in a speaker, as i can only imagine it working at short wavelengths, which would be directional and not too audiable from the front, but hay, it would be great if someone more learned could come along and shead some light on the subject. cheers dave ------------- They keep telling me life is short, but its the longest thing ive ever done!!! |
Posted By: Abe The Babe
Date Posted: 25 November 2012 at 12:57am
| The mic'ing technique is more for recording than anything else tbh. |
Posted By: Abe The Babe
Date Posted: 27 November 2012 at 2:16pm
| No panning can be done. |
Posted By: b grade
Date Posted: 27 November 2012 at 2:55pm
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I would think it would work more like a surround setup minus the rear speakers. There could be a center stack, and two wide stereo stacks. The center stack would play all the mid program, and the side stacks would obviously play all the side programming. If you put all of the stack together, you would lose the wide stereo separation and I would think it would sound similar to just running a mono stack. Personally, I would set mid section up to run full frequency and the sides just with mids and highs. I use mid side processing in logic all the time, and have given some thought to setting my PA up, but I don't have a good gigging laptop. I have hardware which I could use to do it too, but have never actually done it.
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Posted By: studio45
Date Posted: 28 November 2012 at 3:23pm
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This guy yeah? Be interesting to do it on a large scale. One would simply feed three directional mid-highs, placed at 90 degrees to each other, with the outputs of a standard MS encoding done on a mixing desk with the aid of a couple of y-splitters. So forward facing speaker receives L+R (mono sum), left and right facing speakers receive L-R (signals summed out of phase), either left or right facing speaker is run polarity inverted. Now, if a sound pans from L to R on the original recording, it should also appear to pan L to R in the soundfield from this mid-side stack. Directivity would be interesting, on the face of it you would expect a nice 180 degree dispersion but the side speakers aren't playing all the music so there would be some loss of information as you move outside the coverage of the forward-facing speaker. No-one I know actually has three big loud narrow dispersion mid-highs all of the same model, so it'll be a while before I get to try this....
------------- Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA |
Posted By: b grade
Date Posted: 28 November 2012 at 3:59pm
| In true mid side processing, the mid program should just be playing what is identical on left and right, and the side programs are playing only the material which is not identical on the left and right. |
Posted By: boab
Date Posted: 28 November 2012 at 8:01pm
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I have tried this in my studio/ test room. Its has more stable spacial effect across the listening field but is less convincing than true stereo for the main area. I found it to work well will with Guitar as you can use two cabs as long as the back cab is at 90deg to the front cab and is open back. I set up and tweeked delays with good effect. Best Boab |
Posted By: Monkeys
Date Posted: 28 November 2012 at 11:27pm
Just thought I'd let you know that the way the brain interprets distance from information from the eyes is very different to the way it does so from the ears. With the eyes the brain mainly uses the differing information from the left and right eyes to determine depth, called 'spatial disparity'. This is how 3D glasses give the perception of depth, by delivering two slightly different images to each eye. With the ears, since the speed of sound is relatively slow, the different times at which a sound reaches each ear can be used, as you said, to perform a sort of 'triangulation' of the origin of the sound, this is also coupled with the differing loudness in each ear to give better accuracy. The really impressive part, for me at least, comes in the brains ability to interprets sounds in 3 dimensions, that is, in front, behind, above, or below. As merely using the difference in timing and loudness in each ear would only really give you the location relative to left or right. If that were the case, then an identical sound coming from 2 o'clock, would be perceived the same as if it came from 4 o'clock. But it isn't, we are able to perceive when something is behind us, or above or below us, even with our eyes closed. This is something which is actually still relatively poorly understood from a neuroscience perspective. It is believed that it involves a very subtle interaction between the sounds timing information and the shape of the ears, and the way that the sound is 'funneled' into the ears. So that a sound coming from above, will be funneled in along the base of the ear canal, and then stimulate a specific part of the cochlea more strongly than if it were coming from the bottom, and vice-versa. Giving the perception of 3 dimensions! Hopefully someone finds that as interesting as I did writing it! I did a degree in Neuroscience and hardly ever get to use the information that I've learned, so thought I'd jump at the opportunity 
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thepersonunknown wrote:Posted By: hond
Date Posted: 01 December 2012 at 1:46am
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"I made a comment two days ago about designing a mid side speaker array. Ted Fletcher and a few others have designed speakers that are based on the mid side technique (but using speakers to reproduce stereo instead of mic's to record stereo) Airsound etc. I have put a lot more thought into this since the comment and I'm not sure how it can actually make sounds appear left or right as the time of arrival differences would be next to non existant (which is part of the idea) and I don't understand how you recieve the guitar for example at a higher level at one ear than the other. It does make sense though that by altering the amount of a sound in the side speakers the image can be made wider, or further away, maybe general area left or right based on the reflections from the left side of the room vs right side, but if that were the case the more you tried to make an instrument appear left or right the further away the sound would appear." I don't think M/S speakers will be able to create a real soundstage. IMO even stereo speakers don't create a perfect illusion of a sound stage. I would say that M/S speakers create a sense of space and width. The main advantage is the sweet spot being not limited to one specific point including improved clarity and lack of distortion which is normally caused by having 2 speakers playing a mono signal. Stereo is more often used for stereo effects and to make reverb sound more impressive rather than to use it to create a soundstage I think. It is also often used to give instruments which are in the same frequency zone more room to breathe. I would say it's rather a thing that is used for creativity and to have the option of lighten up the mix than to actually help create an illusion of a real sound stage.
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Posted By: thepersonunknown
Date Posted: 01 December 2012 at 11:04am
very interesting mate. a lot of stuff i had neer even thoug about there  cheers ------------- They keep telling me life is short, but its the longest thing ive ever done!!! |
Posted By: hond
Date Posted: 01 December 2012 at 11:37am
| when you compare those binaural recordings with that matchbox recording supposedly done with holophonics by that guy Zuccarelli I'm always amazed that the holophonics recording succeeds at giving you the illusion that the sound is front of you when wearing headphones; I haven't heard this with binaural recordings yet |
Posted By: cyte
Date Posted: 11 January 2013 at 12:53am
This is why I love speakerplans
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Posted By: hond
Date Posted: 18 January 2013 at 3:22pm
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I have been doing some serious testing with this mid/side technique and the results are interesting: 1. You don't get a stereo image at all: the point of this mid/side technique (with mono center and inverted sides) is to create some sort of an illusion of a room or a concert hall with sound bouncing off the side walls. Directional information? Do not count on it. 2. Reverb sounds amazing: yes reverb sounds even better than on regular stereo AND it sounds the same no matter where you stand in the room 3. the mono/inverted sides create a very different mixdown of a track. Certain intruments, heavily panned can disappear or become too loud. Sometimes vocals just disappear and sometimes you hear instruments you never heard before when you were listening to a normal stereo system. One note: although sometimes you hear an entirely different mixdown: it still sounds very good and pleasing and balanced.. just very different from what you're used to. It's quite strange actually. 4. you do get a nice soundfield that is the same no matter where you stand in the room. No more sweet spot! 5. Bass clarity improves! This doesn't need much explanation I think. 6. movies are amazing! if you place the system below the screen, the voices appear to come out of the screen and they have a lot of clarity. All in all; I think this is pretty interesting.. but if some one knows a way how to filter out the unique left and right information from a stereo signal, please tell me because IF there's a way to do it... that would just be awesome. my test setup: center speaker: mono signal (L+R) left side speaker (very close to the center speaker): side signal (L-R) right side speaker (very close to the center speaker): side signal (L-R) -> inverted I ran everything through ableton. You can also do it the analog way by changing the polarity of XLR cables. |
Posted By: b grade
Date Posted: 18 January 2013 at 4:20pm
| To present only the unique left and right, using software, I would just use a mid/side plugin and mute the mid and send the resultant signal to the left and right. |
Posted By: hond
Date Posted: 18 January 2013 at 4:38pm
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I did not know plugins like that existed. Looks like I've got some new material to test out :) |
Posted By: hond
Date Posted: 18 January 2013 at 5:01pm
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http://www.voxengo.com/product/msed/ EDIT: hm upon further investigation I don't think this program is capable of filtering out the true stereo information |
Posted By: b grade
Date Posted: 18 January 2013 at 5:15pm
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I use MSED too. When producing I find that I can get nice surround sound effects by adding gain to the side and reducing it to the mid.
It works for me. If you run in a mono signal and mute the mid, it is silent. If you bounce a track after you mute the mid, so it is only stereo, and then run the resultant track through with the sides muted, it is also silent. You can do similar things with a compressor with side chaining capabilities, but it takes some doing. |
Posted By: hond
Date Posted: 18 January 2013 at 5:43pm
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yeah all well but I knew about that. I thought you said the side button gave me the unique left vs. right stereo information. what I mean: unique Left stereo = only the information that is different from the right channel unique Right stereo = only the information that is different from the left channel There's no way you can get that information out of a stereo file without some funky brain twisting algorithmic digital processing. I've broken my brains over it and it is impossible to achieve in an analog thinking kind of way if that makes sense to you |
Posted By: hond
Date Posted: 18 January 2013 at 5:45pm
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the encode mode sends L-R or R-L to your right speaker. the decode mode probably sends L-R to the right speaker and R-L to the left (and the other way round) but with a bit of mid mixed in i think the incline mode sends L-R to the right speaker and R-L to the left (or the other way round) |
Posted By: bob4
Date Posted: 19 January 2013 at 12:13am
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For "true MS playback" you would in theory need a dipole loudspeaker for the S signal..... electrostatics anyone??
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Posted By: hond
Date Posted: 19 January 2013 at 2:43am
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if you want to mirror a mid sid mic setup, yes. what I'm looking for is something different
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Posted By: RussD
Date Posted: 10 March 2015 at 4:25pm
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Not sure if members of this forum are aware of the following: A commercial version of a mid-side speaker system has been offered for quite some time. I bought two Space Station Mk II powered "single point stereo" speakers that were designed by Aspen Pittman when he owned and operated Groove Tubes. I use them regularly when playing small to medium sized gigs (guitar, vocals, keyboards). The 300 degree sound field from these things is amazing! Not really true stereo, however, they reproduce the stereo effects used in keyboards (like that of a Hammond Leslie cabinet) remarkably well. They provide an output for a subwoofer then when used rolls off everything below 100Hz from the internal speakers since the sub will then be handling that. The internal speakers are about 10dB down at about 60Hz. The "stereo" effect projected by these speakers is even anywhere in a room - a very interesting phenomena that is very pleasing compared to mono. Conventional stereo does not work well in for live sound PA system applications.
Info on the Space Station MkII (no longer produced) can be found here: http://www.sweetwater.com/store/detail/SFXSSmkII Info. on version 3 of the Space Station (current production version) can be found here: http://www.centerpointstereo.com/about.php |
Posted By: mediatechnology
Date Posted: 01 July 2015 at 1:35am
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Hi. This is my first post here. I found this place while searching for information on Mid Side Speaker arrays. I was recently ask to modify one of my MS Mid Side Matrix boards for a guitarist who had used the Centerpoint Space Station but felt it under-powered and wanted to try it with larger amps and different speaker arrangements. In the process of adapting an existing mastering width circuit I had a chance to listen to a three speaker Mid Side Array and was blown away by the huge ambient image. I was impressed enough to want to build another one for myself for casual listening. I've posted my thoughts on proaudiodesignforum.com along with schematics for the encoder: http://www.proaudiodesignforum.com/forum/php/viewtopic.php?f=6&t=742 This is the Mid Side board and Width control. Only half the board is used.  The inputs are Left and Right; the outputs Mid and Side. The Width Control varies Side from 0 to 100% as Mid is varied from 100% to 0%. Four of the ICs provide balanced I/O. The heart of the MS encoder circuit are two THAT1240 and a dual op amp such as the LM49860, NE5523 or NJM2114. |
Posted By: bob4
Date Posted: 04 July 2015 at 9:54am
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wow that looks nice! |
Posted By: angelineacord
Date Posted: 22 July 2015 at 8:29am
| The positioning of speaker at the mid side is not a bad idea. |
Posted By: mediatechnology
Date Posted: 22 July 2015 at 7:39pm
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Thanks everyone. I'm really anxious to get the speaker array set back up and have some of my geek neighbors come over and listen to it. |