xpat Posted March 13, 2017 Report Share Posted March 13, 2017 I enjoy experimenting with speaker placement, sound treatments, and acoustics in general. My latest adventure has provided some interesting results - interesting because my significant other is never impressed with any of my tweaks. I usually hear the comment “ it sounds good – but I really can't tell the difference”. This time the comment was – it sounds great! I agree. The adventure started after reading an interesting article about Brahms Symphonies on Direct to Disk Vinyl (April 2017 issue of the absolute sound magazine). In the article, the author (Robert E. Greene) states that the least artificial way to record direct to disk is to use the Blumfield stereo microphone technique. In this microphone technique, the sound field - at a single listening position - is recorded in a figure 8 pattern – the mics are almost in the same spot, and the axes of the are mics crossed at 90 degrees. According to the author, “Blumlein stereo presents a real event that the brain can process at the basic level of natural sound listening.” I was very skeptical, but found the concept interesting. (If you're interested, here is a link: https://en.wikipedia.org/wiki/Blumlein_Pair ) To cut to the chase, the author said you can set up an accurate Blumlein playback with the listener close to the speakers, and the speakers separated by 90 degrees. I tried it in my rec room by putting one AR5 on the long wall, and the other 8 1/2 feet away on the short wall. (Both speakers facing forward resulting in a 90 degree setup.) I picked an album where we both enjoy the performance, but always felt the sonics left much to be desired. (This feeling was consistent regardless of the amp and speakers - AR5s, AR6s, AR9s or Sound Dynamics.) The results were quite amazing – at least in my listening space. If you like to experiment, give it a try.... Link to comment Share on other sites More sharing options...
Aadams Posted March 13, 2017 Report Share Posted March 13, 2017 This rang a bell for me. I went to the wiki you linked which mentioned ambisonic recordings that use Blumlein principles. I thought I had seen this somewhere before and it turns out Nimbus has been recording and issuing performances using these techniques since the 1970s. If you like classical music or recorded live performance Nimbus recordings are high quality. Adams Link to comment Share on other sites More sharing options...
AR surround Posted March 13, 2017 Report Share Posted March 13, 2017 I recall an article way-back-when in Stereo Review where they discussed speaker placement. They described a similar placement - each speaker on an adjacent wall - as one of the better arrangements for achieving satisfying sound. Link to comment Share on other sites More sharing options...
iso Posted March 13, 2017 Report Share Posted March 13, 2017 Tapio M Köykkä patented ortoperspekta stereo system that was very useful when listening recordings made using Blumlein principle in 1962. This concept used monophonic center channel for M signal and two smaller speakers to create S (difference) signal. Köykkä patented also vastavaihevahvistimen-principle in 1952, that was later called as circlotron in the USA. Kimmo https://fi.wikipedia.org/wiki/Tapio_M._Köykkä http://circlotron.tripod.com/koykka-patent1.pdf Link to comment Share on other sites More sharing options...
Aadams Posted March 14, 2017 Report Share Posted March 14, 2017 (Both speakers facing forward resulting in a 90 degree setup.) I picked an album where we both enjoy the performance, but always felt the sonics left much to be desired. (This feeling was consistent regardless of the amp and speakers - AR5s, AR6s, AR9s or Sound Dynamics.) The results were quite amazing – at least in my listening space. If you like to experiment, give it a try.... Does it have to be a 90 degree setup? What was your seating position relative to both speakers. For example, were you equidistant from the speakers and facing the corner of the room between the speakers or were you facing one of the speakers? Is there an exact sweet spot where the phenomenon is experienced or is there freedom to move about? I have a room where I would try this if positioning is not too restrictive. Adams Link to comment Share on other sites More sharing options...
stan461 Posted March 16, 2017 Report Share Posted March 16, 2017 The quote from tyhe Wikipedia articel on playback is: "Blumlein Pair is the name for a stereo recording technique invented by Alan Blumlein for the creation of recordings that, upon replaying through headphones or loudspeakers, recreate the spatial characteristics of the recorded signal." It seems this "Blumlein Pair" is a recording technique. Not sure if similar speaker placement is necessary for playback. At least according to the Wiki article. Speaker placement, and especially room treatment, are probably at least as important as the chosen speakers. Most listeners tend to minimize "the room" due to the aesthetic and/or monetary penalty that is incurred which can be quite substantial. Link to comment Share on other sites More sharing options...
Aadams Posted March 16, 2017 Report Share Posted March 16, 2017 53 minutes ago, stan461 said: The quote from tyhe Wikipedia articel on playback is: "Blumlein Pair is the name for a stereo recording technique invented by Alan Blumlein for the creation of recordings that, upon replaying through headphones or loudspeakers, recreate the spatial characteristics of the recorded signal." It seems this "Blumlein Pair" is a recording technique. Not sure if similar speaker placement is necessary for playback. At least according to the Wiki article. Speaker placement, and especially room treatment, are probably at least as important as the chosen speakers. Most listeners tend to minimize "the room" due to the aesthetic and/or monetary penalty that is incurred which can be quite substantial. Nimbus records uses a Blumlein derived (Ambisonic) method in its recordings and on their website states that the spaciousness can only fully be experienced on a multichannel system with proper decoding which is mostly lost in a 2 channel presentation. Nimbus has been issuing Ambisonic recorded music at least since the 1970s and is now re-releasing some on multi channel DVD. I only have a couple of Nimbus stereo CDs which in my opinion are at least as good as the Telarcs. If you like listening to music well recorded live, in a concert hall, Nimbus is a safe bet. Regarding speaker placement: I would be willing to experiment with bookshelf speakers just to see if there is something to it but agree that the key is in the recording technique and proper decoding. I would not move 9s and 3s before I knew there was a big payoff because, effort aside, it would require an audience with She who must be obeyed. https://en.wikipedia.org/wiki/Nimbus_Records Link to comment Share on other sites More sharing options...
xpat Posted March 22, 2017 Author Report Share Posted March 22, 2017 Hello, I've been tied up with some personal issues and have not had time to respond to some of your comments and questions. Here goes.... AR Surround - I used to read Stereo Review but must have missed the article that addressed placing speakers on an adjacent wall to achieve satisfying sound. Thanks for the information - I may try to find the article at my local library! Aadams - The Absolute Sound magazine article indicated you can get an idea of the Blumlein recording technique during playback. Position the speakers 90 degrees to each other and sit close to them. I set my chair equidistant from the speakers. The back of the chair (where my head is positioned ) is about 5 feet back from the speaker directly facing me. As all rooms are different acoustically, feel free to move the chair around to get the best sound. I recognize that the music I'm listening to was not recorded using the Blumlein recording technique. However, the 90 degree placement sounds great in my room. From the beginning, I've wondered how a performance using the Blumlein recording technique would sound using this new set-up. Thanks to Aadams' tip about Nimbus records, I may get that chance. I'll be checking out their catalogue! Bye the way, I need to listen to some of the 35MM Mercury Living Presence CDs engineered by Wilma 'Mozart' Cozart. If I recall, those recordings were made with only 3 mikes. Stan461 – I totally agree with your comment that “Speaker placement, and especially room treatment, are probably at least as important as the chosen speakers.” Regarding room set-up and treatments, my experience is that they have a huge effect on the sound – clarity, soundstage and bass. I bought some sound treatment panels (1ft square) from a home improvement store that made a big difference in the sound. The cost was under $30 and rid my room of a slap echo problem. Guess I love to tweak. I wish I had the time to study acoustical engineering - maybe that will occur in another life. ISO – Thanks for the information on Tapio M Köykkä – I had never heard of him, but it appears he was way ahead of his time with 3 channel playback – the father of multi-channel audio! I'll definitely be reading more about him. Link to comment Share on other sites More sharing options...
teknofossil Posted March 23, 2017 Report Share Posted March 23, 2017 Since we are discussing system placement I thought I'd offer up this concept suggested by Ted Jordan. I tried it with some small EPI systems and it seems to work quite well. When I experimented with this set up I found that a more defined sense of depth, image specificity could be had by placing sound absorbing material on the wall in between the systems. Logic here being the sharp inward angle resulted in more reflected upper frequency sound waves from the wall, effecting the stereo imAGE. Give it a try. -T Link to comment Share on other sites More sharing options...
xpat Posted March 26, 2017 Author Report Share Posted March 26, 2017 -t, I'll give it a try - looks like an interesting concept. Thanks for the information! Link to comment Share on other sites More sharing options...
Aadams Posted June 6, 2017 Report Share Posted June 6, 2017 On 3/25/2017 at 9:18 PM, xpat said: -t, I'll give it a try - looks like an interesting concept. Thanks for the information! I said I would give Blumlien placement a try and I have. I am setting up a speaker array with sub woofers and the two channels are currently arranged almost exactly the way the diagram above is drawn with respect to the listening position. The perpendicular arrangement really creates a spacious sound and channel separation seems to be enhanced in some strange spooky way that is not unpleasant but it is unusual to my ears. The images as drawn do seem to appear on some recordings BTW. This is not your standard left/right channel experience you must be in the off-center sweet spot. Link to comment Share on other sites More sharing options...
Aadams Posted June 16, 2017 Report Share Posted June 16, 2017 I don't normally get excited about moving speakers around but I must admit, TSW! Since my last post I have modified the speaker arrangement to the 90 degree setup described in the OP above and am now running stacked pairs on each channel. The top pair are angled while the bottom pair remain flat against the wall. On classical music and live recordings the results can be astounding.. The stereo image is broad and stable with no particular sweet spot. Link to comment Share on other sites More sharing options...
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