nrenter Posted September 28, 2022 Share Posted September 28, 2022 3 minutes ago, Holmz said: Relative to all the tones within the signal itself. There is no absolute phase, it is relative. Let’s take the square wave… If it get projected out of the cabinet as perfect field, except for the mid range getting inverted, then the PSD of it will look largely the same as the with the the mid range not inverted. But in the time domain, it stops looking like a square wave. … and the impulse response would also have a “giddy up” in it, and not look like a Dirac delta function. I'm sorry...I'm not following you. The a sound wave that impacts a microphone transducer is what is it - an aggreate wave comprised of direct and reflected, in-phase, phase-shifted, and out-of-phase waves. You are right...there is no "absolute phase" because without a reference, phase is relative. However if you compare the wave directly emanating from the horn of a saxophone to that same saxophone mic'ed 5 meters out in a room, the sound is VERY different. Why? Time and phase distortion of the far-field wave compared to the near-field wave. Reverberation, aka time distortion, is added to the wave captured by the far-field tranducer. Physical placement of the mic may capture room-specific nulls or peaks, aka phase distortion. Which mic is capturing a time and phase accurate signal? This is the art. Both are time and phase accurate at each particular point in space. However, strictly speaking, the far-field mic is not capturing a time and phase accurate wave (with respect to the near-field wave). This is why I said asking about a “time and phase accurate” recording doesn’t really make sense. Link to comment Share on other sites More sharing options...
Richard Vandersteen Posted September 29, 2022 Share Posted September 29, 2022 2 hours ago, nrenter said: I'm sorry...I'm not following you. The a sound wave that impacts a microphone transducer is what is it - an aggreate wave comprised of direct and reflected, in-phase, phase-shifted, and out-of-phase waves. You are right...there is no "absolute phase" because without a reference, phase is relative. However if you compare the wave directly emanating from the horn of a saxophone to that same saxophone mic'ed 5 meters out in a room, the sound is VERY different. Why? Time and phase distortion of the far-field wave compared to the near-field wave. Reverberation, aka time distortion, is added to the wave captured by the far-field tranducer. Physical placement of the mic may capture room-specific nulls or peaks, aka phase distortion. Which mic is capturing a time and phase accurate signal? This is the art. Both are time and phase accurate at each particular point in space. However, strictly speaking, the far-field mic is not capturing a time and phase accurate wave (with respect to the near-field wave). This is why I said asking about a “time and phase accurate” recording doesn’t really make sense. I think what most people are talking about is having all the microphones wired in the same polarity. Instruments will interact with other instruments at different distances with their harmonics interleafing together within the acoustic space so who knows what is happening with time, amplitude and phase but the mix of all this is what the engineer wanted. Having all of the microphones and various pickups in the same polarity would sound more organized on a Time and Phase Coherent speaker, IMO. RV 3 1 Link to comment Share on other sites More sharing options...
Holmz Posted September 29, 2022 Share Posted September 29, 2022 (edited) 7 hours ago, nrenter said: I'm sorry...I'm not following you. I’ll try more - but I may not be a good explainer. 7 hours ago, nrenter said: The a sound wave that impacts a microphone transducer is what is it - an aggreate wave comprised of direct and reflected, in-phase, phase-shifted, and out-of-phase waves. You are right...there is no "absolute phase" because without a reference, phase is relative. I believe that it is more a case of the field contain the superposition of the direct sound, and all the comb of the echos. If the phase of all the components of say a square wave, have an order, then I want that order to be preserved. The Mic preserved the phase “relationship”, but maybe the square wave is upside down if the polarity if flipped. The speaker may or may not preserve that, so that is technically HiFi when a speaker maintains a closer fidelity between output and input. Maybe it won’t sound better, but it mathematically closer to having the emitted field match the sampled field. 7 hours ago, nrenter said: However if you compare the wave directly emanating from the horn of a saxophone to that same saxophone mic'ed 5 meters out in a room, the sound is VERY different. Why? Time and phase distortion of the far-field wave compared to the near-field wave. Reverberation, aka time distortion, is added to the wave captured by the far-field tranducer. Maybe we call that a comb of reverberation? It is not a distortion, as it is just the measured/sampled field. But I agree iut has more stuff in it.. 7 hours ago, nrenter said: Physical placement of the mic may capture room-specific nulls or peaks, aka phase distortion. That could be a distortion, and at least for a tone could look like one. Or it is the superposition of the direct and reflected sound cancelling. 7 hours ago, nrenter said: Which mic is capturing a time and phase accurate signal? This is the art. Both are time and phase accurate at each particular point in space. However, strictly speaking, the far-field mic is not capturing a time and phase accurate wave (with respect to the near-field wave). I believe that it is capturing the field accurately. Just that the close mic has less R^2 loss, so the reflections appear way smaller. 7 hours ago, nrenter said: This is why I said asking about a “time and phase accurate” recording doesn’t really make sense. I think I like Richard’s “Polarity” definition. Other speakers can also sound different when the polarity is flipped, it is not only Vandy speakers that do it. But if every other speaker is flipped, then it is hard to define the best case… If the music is heavy in one band it will be a different “best polarity”`than some other music with a different band being used more. Edited September 29, 2022 by Holmz Link to comment Share on other sites More sharing options...
ctsooner Posted September 29, 2022 Share Posted September 29, 2022 On 9/27/2022 at 4:40 PM, BKDad said: I know that I've told this story before, but I think it applies here. When my daughter was back in elementary school, she was part of the school band. Like most school bands of the day, they had a winter concert and a spring concert. Being a geeky type of Dad, I thought I'd do something to record these concerts. So, I purchased a brandy new Sony Walkman Pro (from J&R Music, no less) and a pair of Sonic Studios binaural microphones. Long story short, I had about two hours of experience using this rig before the first concert. My entire sound engineer effort was to make sure the mic gain was about right on the Walkman Pro, sit with my head still, and not cough. Oh, and change the cassette when it was time to. I didn't expect much. If this recording was about the aural equivalent of a home movie, that would be more than good enough. So, I was quite shocked when I played the output of the Walkman Pro back through the living room sound system, which included Vandersteen 2Ci's. It sounded as good as the best recording in our entire collection. That wasn't vanity or ego speaking. Huh? It certainly wasn't due to my expertise (😂) or the great equipment I was using. What I finally decided was that the recording people had their idea of what the musicians wanted and what would appeal to the customer base and therefore sell. That didn't necessarily align with what I thought sounded plausibly real. But, that's the way it is. So, I think choosing the records you like and playing them back through the equipment you like is what matters. Except for the folks who are competing in the marketplace, this isn't a competition. What a cool story. Thanks for sharing again, as I forgot that you shared earlier, lol. When I was a J school student, I always recorded live music events when I could get the equipment. Back then, most didnt' have a problem with us making recordings of the concerts as it was for the school and not personal gain. The personal gain side was gettign to listen to these recordings on my dorm system. There was always a rightness about what we recorded. I'm almost glad I didn't become an engineer. If pushed, I may have done it. This thread is very interesting and I do understand nearly everything you guys are posting (in principle), but I am glad that I'm so much more content with my listening now days than I ever was in the past. It all started when I switched to Vandersteen's from years of Pro Ac's. It took Rutan all of 2 cuts to noticed the major difference as I was auditioning Treo's vs Pro Ac D series. I was hooked and at that point I had zero idea why. I promise I will try not to even think of this thread when I wake up this morning and put on some music to start my day (recovering from a rough spot of Covid this week. I set my goal to get out in the other room for a spell and listen on the main system and not my portable one! I guess it's like anything else, it doesn't matter how or what, as long as it's sounding that much better than the others. That's what Vandy does for my ears. Link to comment Share on other sites More sharing options...
DC-93 Posted September 29, 2022 Author Share Posted September 29, 2022 Speaking of ears, we all have the same 2 ears, but all have different response curves! (partial explanation of the many brands of speakers out there?) Personally, I can't hear past 13K. I also can't hear certain crickets with my left ear, another issue of mine that's lower in the hz scale... That probably has to do with tinnitus in my left ear. But I still do enjoy music! My loss doesn't really affect the majority of sound! 1 Link to comment Share on other sites More sharing options...
Richard Vandersteen Posted September 29, 2022 Share Posted September 29, 2022 2 hours ago, DC-93 said: Speaking of ears, we all have the same 2 ears, but all have different response curves! (partial explanation of the many brands of speakers out there?) Personally, I can't hear past 13K. I also can't hear certain crickets with my left ear, another issue of mine that's lower in the hz scale... That probably has to do with tinnitus in my left ear. But I still do enjoy music! My loss doesn't really affect the majority of sound! One's hearing ability has very little to do with the speaker because a recorded piano must be properly reproduced in order to sound like a real piano sounded yesterday live for all of us. This requires bandwidth far beyond the limits of anyone's diminished hearing. 45 years ago, one of our listeners on our "Live vs. Recorded" panel could hear to 10K only but could 100% of the time identify a super tweeter coming in at 15K. If your reference is live sounds our ears are recalibrated every day, if your reference is what you remember in your youth you will need a lot of tweeters! RV 2 Link to comment Share on other sites More sharing options...
DC-93 Posted September 29, 2022 Author Share Posted September 29, 2022 Back in the 70s, I had crappy house speakers, so my treble memories are bad!! AM radio in the 68 Charger, with the tone knob dialed up... 😂 I watched the video. Excellent! The waterfall plot was enlightening. Thank you. 2 Link to comment Share on other sites More sharing options...
GdnrBob Posted September 29, 2022 Share Posted September 29, 2022 7 hours ago, Richard Vandersteen said: 45 years ago, one of our listeners on our "Live vs. Recorded" panel could hear to 10K only but could 100% of the time identify a super tweeter coming in at 15K. This is very interesting. I guess our hearing compensates for our deficiencies. -Though, I would have preferred to have my hearing intact and capable of 20-20K hz..😉 B 2 Link to comment Share on other sites More sharing options...
grue2cesig2 Posted October 8, 2022 Share Posted October 8, 2022 (edited) whoever this richardvandersteen user is, he's right on it. 🙂 any sound made in the real world is going to have all sorts of phase and time stuff going on. whether it's a row of violins 3 deep, layered chorus behind that... any one sound from one instrument or voice is going to resonate, bounce and interfere with every other sound in the area. reinforce or subtract, even ala duntech where it was just 1 guy with a guitar sitting between two sovereigns for their live vs recorded demo, the strings of the strum are going to be diminished or reinforced by the guitar body, the artists body, the speakers, the room all of that. to me it would be impossible to define what a perfect in phase time coherent recording would even be. it's a lot like the physics thing where you can either know for sure where a particle is or what direction it's traveling, but you can't know both for sure. you'd really have to look at what a perfect pure sound is. then have to figure out how to capture that and reproduce it through speakers, but again then everything gets weird. a speaker is really supposed to, well depending on their purposeful design, a speaker is supposed to be like the clearest most transparent colorless plate of glass that is also perfectly flat. transparent. sound familiar? that applies to amps, preamps, speakerwires, etc. too. it's quite zen - the speaker maker or amp maker etc say "the best we can do is nothing". weren't there or aren't there currently speakers or experiments with point-source speakers but they never sounded quite right? that's even a distortion because nothing in reality is a point source sound. back when i sold equipment, i'd probe to find out what kind of listening the potential client wanted to do and what type of music - if they wanted a house party, i'd walk them over to stuff that could play LOUD and had lots of bass. if they weren't sure, i'd go for the "good stuff". a side note, two of the easiest clients i had, 1 was a violinist and the other a traveling opera singer and they were both as thankful and happy as could be after i exposed them to the "good stuff" so i suppose that leaves us with exactly what's already been said: if we (meaning they) begin to add the art to our playback systems we begin to travel a different road. well is that wrong? no. it's just different. but there are people that want that clear flat glass plate that doesn't obscure our view. and to keep on boring everyone.... i am amazed that somehow we wind up with "depth" and "width" and 3 dimensionality at all, given that the 3d live is compressed down to 2d as soon as it hits the microphones or even our ears! i'll leave that to the engineers and physicists and people with a lot more experience than me. a final thought, in large important scientific telescopes they are looking at mechanical or digital adaptive optics that cancel out atmospheric refraction of light for ground based instruments or even low frequency noise (vibrations), for example someone walking across the floor. maybe there's some new adaptive audio capture and playback systems. maybe recording every instrument separately in a dead-room and then blending them all together would get us closer to a perfect recording/playback - but we'd still need speakers that do nothing 🙂 ha! Edited October 8, 2022 by grue2cesig2 1 Link to comment Share on other sites More sharing options...
Holmz Posted October 8, 2022 Share Posted October 8, 2022 2 hours ago, grue2cesig2 said: whoever this richardvandersteen user is, he's right on it. 🙂 any sound made in the real world is going to have all sorts of phase and time stuff going on. whether it's a row of violins 3 deep, layered chorus behind that... any one sound from one instrument or voice is going to resonate, bounce and interfere with every other sound in the area. reinforce or subtract, even ala duntech where it was just 1 guy with a guitar sitting between two sovereigns for their live vs recorded demo, the strings of the strum are going to be diminished or reinforced by the guitar body, the artists body, the speakers, the room all of that. to me it would be impossible to define what a perfect in phase time coherent recording would even be. it's a lot like the physics thing where you can either know for sure where a particle is or what direction it's traveling, but you can't know both for sure. you'd really have to look at what a perfect pure sound is. then have to figure out how to capture that and reproduce it through speakers, but again then everything gets weird. I dunno I sort of thing of it like each Violin that is resonating will have harmonics that are in some relative phase with the fundamental and the other harmonics. If there is a wall behind the violinist then quick echos will inform me that they are in the back, and if the echos take longer, then I know that they are in the middle or the front. And with two or three players, each of the harmonics will be relative to their fundamentals. I really do not care what the superposition of the complex signal/waveform is in amplitude and phase. I just want to make sure that the playback system is not shifting frequency bands around in phase any more than it has to. 2 hours ago, grue2cesig2 said: … a final thought, in large important scientific telescopes they are looking at mechanical or digital adaptive optics that cancel out atmospheric refraction of light for ground based instruments or even low frequency noise (vibrations), for example someone walking across the floor. maybe there's some new adaptive audio capture and playback systems. maybe recording every instrument separately in a dead-room and then blending them all together would get us closer to a perfect recording/playback - but we'd still need speakers that do nothing 🙂 ha! I think that they do some of the reverb stuff digitally to add in room ambiance, but I am not 100% sure. There are some active bass traps. And maybe the servo systems are more like active control. There are also feed forwards control systems, which can be applied to amplifiers. And then in camera and larger optics they also do some s/w processing like maximum entropy, to sharpen the image. That is probably more a DSP doing DIRAC, and getting the group delay removed to get a sharper impulse response… While I find it all pretty cool, I am still running the 38 year old speakers. 1 Link to comment Share on other sites More sharing options...
DC-93 Posted October 16, 2022 Author Share Posted October 16, 2022 Here's the upstream influences that may hinder the best time aligned and in phase sound! Hundreds of feet of wires, a bunch of potentiometers and sliding rheostats! ARGH!!!! Then you have direct to disc Sheffield Sound Labs products! 👍 Link to comment Share on other sites More sharing options...
Holmz Posted October 16, 2022 Share Posted October 16, 2022 6 hours ago, DC-93 said: Here's the upstream influences that may hinder the best time aligned and in phase sound! Hundreds of feet of wires, a bunch of potentiometers and sliding rheostats! ARGH!!!! Then you have direct to disc Sheffield Sound Labs products! 👍 In the section from 5:30 t0 6:15 RV says that the electronics chain is time and phase correct. Who am I to argue? (Plus he is correct.) A mile of cable in a console will shift the timing by k*1/186000, which is PDC to zero. (The only thing in the mixing console that will have any effect is a phase/invert switch.) I like the Sheffield stuff as much as the next person. And they still have lots of cable, microphone amps, and a mixing console in the Sheffield recordings. It is not like a Fred Flintstone approach, where the it done mechanically and not using any cables. 1 Link to comment Share on other sites More sharing options...
Richard Vandersteen Posted October 16, 2022 Share Posted October 16, 2022 7 hours ago, DC-93 said: Here's the upstream influences that may hinder the best time aligned and in phase sound! Hundreds of feet of wires, a bunch of potentiometers and sliding rheostats! ARGH!!!! Then you have direct to disc Sheffield Sound Labs products! 👍 Yes, but none of that will cause the midrange to be 180 out compared to the woofer and tweeter frequencies! RV 1 2 Link to comment Share on other sites More sharing options...
DC-93 Posted October 17, 2022 Author Share Posted October 17, 2022 There was an engineer I knew at work in the 80s that was really into audio. He was against any use of tone controls in any part of the recording chain, saying they "changed the phase". He went into a very elaborate explanation of the physics involved, which was way above me! I have to update my thinking! 👍 Excellent video! Link to comment Share on other sites More sharing options...
DC-93 Posted October 17, 2022 Author Share Posted October 17, 2022 Mr. Vandersteen- Were you influenced by the Ohm A and F in the early 70s, being they are phase and time aligned designs? Your thoughts please? I know the Model F influenced me. I could not get over the coherent sound quality off that one driver. Trying to locate those in a house was difficult due to all the reflections you have to deal with a 360-degree radiation pattern. I think a Vandersteen design has the benefits of the Walsh drivers, without the reflection issue. The original Ohm A and F did have some issues in various parts of the musical spectrum, based on proximity to walls and the construction of the cone from 3 different materials, 50 years ago. Thanks. Link to comment Share on other sites More sharing options...
Richard Vandersteen Posted October 17, 2022 Share Posted October 17, 2022 1 hour ago, DC-93 said: Mr. Vandersteen- Were you influenced by the Ohm A and F in the early 70s, being they are phase and time aligned designs? Your thoughts please? I know the Model F influenced me. I could not get over the coherent sound quality off that one driver. Trying to locate those in a house was difficult due to all the reflections you have to deal with a 360-degree radiation pattern. I think a Vandersteen design has the benefits of the Walsh drivers, without the reflection issue. The original Ohm A and F did have some issues in various parts of the musical spectrum, based on proximity to walls and the construction of the cone from 3 different materials, 50 years ago. Thanks. No, I was not able to see solutions to excessive breakup modes (the reason for the different materials) and never had a problem designing a coherent crossover. One advantage of the Ohm f's simple crossover was that many designers' crossovers at the time were not seamless. RV 1 Link to comment Share on other sites More sharing options...
DC-93 Posted October 17, 2022 Author Share Posted October 17, 2022 (edited) 21 minutes ago, Richard Vandersteen said: No, I was not able to see solutions to excessive breakup modes (the reason for the different materials) and never had a problem designing a coherent crossover. One advantage of the Ohm f's simple crossover was that many designers' crossovers at the time were not seamless. RV Indeed, the F had no crossover, depending on the material choices they could figure out at the time to get the sound. IIRC, they were rated at at +/- 4 db. Follow up question: Why did you choose a correct first order crossover setup for your original speakers? thanks. Edited October 17, 2022 by DC-93 clarity Link to comment Share on other sites More sharing options...
Richard Vandersteen Posted October 18, 2022 Share Posted October 18, 2022 4 hours ago, DC-93 said: Indeed, the F had no crossover, depending on the material choices they could figure out at the time to get the sound. IIRC, they were rated at at +/- 4 db. Follow up question: Why did you choose a correct first order crossover setup for your original speakers? thanks. Note the different materials were in fact crossovers except they were mechanical ones which can be modeled electrically. In the early seventies we did a lot of Live vs. Recording listening sessions while developing what eventually became the Model 2. Not until we used one driver per frequency range (except 150 Hz and below), time alignment of the drivers, first order filters and the ability to reproduce a proper step impulse did the recorded sound approach the sound we recorded in the same venue moments earlier according to the listening panel. What is interesting about this, everything we manufacture today is still based on that research 45 years later. RV 1 2 Link to comment Share on other sites More sharing options...
DC-93 Posted October 18, 2022 Author Share Posted October 18, 2022 WOW! I never thought that the 3 different materials on the F were in fact mechanical crossovers! Indeed, you can hear the highs on top, mids 1/2 way down and lows near the bottom of the cone. 50 years ago, they were on the right track. The fact that Vandersteen speakers are refined versions of the originals shows that indeed, you got it right! One day, pistonic drivers for the masses! 😉 Thanks for replying to my questions. 😎 Link to comment Share on other sites More sharing options...
DC-93 Posted October 18, 2022 Author Share Posted October 18, 2022 14 hours ago, Richard Vandersteen said: Note the different materials were in fact crossovers except they were mechanical ones which can be modeled electrically. In the early seventies we did a lot of Live vs. Recording listening sessions while developing what eventually became the Model 2. Not until we used one driver per frequency range (except 150 Hz and below), time alignment of the drivers, first order filters and the ability to reproduce a proper step impulse did the recorded sound approach the sound we recorded in the same venue moments earlier according to the listening panel. What is interesting about this, everything we manufacture today is still based on that research 45 years later. RV Did you experiment with other types of crossovers? How did you figure out the minimum baffle enclosure? Link to comment Share on other sites More sharing options...
Richard Vandersteen Posted October 18, 2022 Share Posted October 18, 2022 4 hours ago, DC-93 said: Did you experiment with other types of crossovers? How did you figure out the minimum baffle enclosure? I started with a well-made box with a slew of drivers and steep filters like everybody does. Started to peel away at it and you know the end result. RV 1 Link to comment Share on other sites More sharing options...
Holmz Posted October 18, 2022 Share Posted October 18, 2022 7 hours ago, DC-93 said: ,,, How did you figure out the minimum baffle enclosure? Baffling … adjective Frustrating; discomfiting; disconcerting. puzzling and frustrating making great mental demands; hard to comprehend or solve or believe 😎 1 1 Link to comment Share on other sites More sharing options...
DC-93 Posted November 24, 2022 Author Share Posted November 24, 2022 A case of smaller is better. 1 Link to comment Share on other sites More sharing options...
DC-93 Posted August 5, 2023 Author Share Posted August 5, 2023 Bump. Anyone else have any new input? Link to comment Share on other sites More sharing options...
GdnrBob Posted August 6, 2023 Share Posted August 6, 2023 Wish I could add something, but I am just a simple gardener...😞 B 1 Link to comment Share on other sites More sharing options...
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