KeithL
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Posts: 10,273
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Post by KeithL on Aug 5, 2016 16:30:55 GMT -5
Yup... but what will be the preferred method next year? I wouldn't say that "LEDE" was so much a rule, or even a method, but more like a rule of thumb. Using "RFZ" to figure out where to put absorbers to catch the early reflections seems like an excellent idea to help ensure good imaging. However, every bit of sound energy that doesn't hit those absorbers or your ears will EVENTUALLY end up being reflected and contributing to the ambient energy in the room. So you do still need to deal with the characteristics of the rest of the surfaces in the room.... (And, of course, the dispersion characteristics of your speakers, and how you position them, will determine how much energy at a given frequency hits which walls.) And, to pick an extreme example, an anechoic chamber would constitute a perfect "reflection free zone". However, everyone I know considers them to sound extremely unpleasant - and, of course, they have zero "room ambience", which is very unnatural sounding. And, to take the opposite example, take the fully tiled pool room at your local gym, and put a stage at one end - with a pair of speakers. Adding a set of absorbers to catch all the early reflections may indeed give you precise pinpoint imaging, but the ambience will still sound like a giant tiled bathroom. So, yes, your waterfall plots will sure show you the problem, but "RFZ" isn't going to tell you how to fix it. (What you're really looking for is to create an area devoid of early reflections, but with a "nice sounding" collection of diffuse late reflections to make it sound like a real room.). Anyway, I maintain my claim, which is that it isn't a simple problem, and doesn't always have a simple answer.... (and it often takes more than a few simple measurements to get all the details). For example, most people agree that one half of the room should be live, and the other half should be dead..... Live End, Dead End (LEDE) used to be popular in the 1980s, but designers have shifted away from LEDE rooms. By using the Time Delay Spectrometry (TDS) measurement technique to analyze the time-energy-frequency (TEF), or waterfall plot of a room the Reflection Free Zone (RFZ) criteria can nowadays be applied without anymore requring the LEDE design approach. |
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Post by copperpipe on Aug 5, 2016 19:26:15 GMT -5
I think Keith just set a record for longest post ever on a single topic... Mark Please. Don't encourage him.  I've learned a ton from his posts; they are factual, free from industry BS, and written in a way that a layman like myself can understand. You're free to skip over them if you wish. No pleasing some people  |
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Post by yves on Aug 5, 2016 23:35:55 GMT -5
Yup... but what will be the preferred method next year? I wouldn't say that "LEDE" was so much a rule, or even a method, but more like a rule of thumb. Using "RFZ" to figure out where to put absorbers to catch the early reflections seems like an excellent idea to help ensure good imaging. However, every bit of sound energy that doesn't hit those absorbers or your ears will EVENTUALLY end up being reflected and contributing to the ambient energy in the room. So you do still need to deal with the characteristics of the rest of the surfaces in the room.... (And, of course, the dispersion characteristics of your speakers, and how you position them, will determine how much energy at a given frequency hits which walls.) And, to pick an extreme example, an anechoic chamber would constitute a perfect "reflection free zone". However, everyone I know considers them to sound extremely unpleasant - and, of course, they have zero "room ambience", which is very unnatural sounding. And, to take the opposite example, take the fully tiled pool room at your local gym, and put a stage at one end - with a pair of speakers. Adding a set of absorbers to catch all the early reflections may indeed give you precise pinpoint imaging, but the ambience will still sound like a giant tiled bathroom. So, yes, your waterfall plots will sure show you the problem, but "RFZ" isn't going to tell you how to fix it. (What you're really looking for is to create an area devoid of early reflections, but with a "nice sounding" collection of diffuse late reflections to make it sound like a real room.). Anyway, I maintain my claim, which is that it isn't a simple problem, and doesn't always have a simple answer.... (and it often takes more than a few simple measurements to get all the details). Live End, Dead End (LEDE) used to be popular in the 1980s, but designers have shifted away from LEDE rooms. By using the Time Delay Spectrometry (TDS) measurement technique to analyze the time-energy-frequency (TEF), or waterfall plot of a room the Reflection Free Zone (RFZ) criteria can nowadays be applied without anymore requring the LEDE design approach. From what I understand, LEDE is just a specific case of RFZ, i.e., the RFZ design criteria must be included in the LEDE design criteria for LEDE to work. Whereas RFZ is a set of design criteria that, when applied to a design, characterize an important part of this design, but like you said, are not the only important part of a design that works. The RFZ criteria are not set in stone, at least not purely. They vary depending on e.g. what type of loudspeakers are used, like monopole "box" speakers vs. bipole infinite-baffle speakers, etc.. so I wholeheartedly agree with you that things aren't as simple nor intuitive as many think, but rather, it is a challenge or you have to be lucky, and in fact that is exactly why some people went to university to study nothing more than acoustics so, again, yes. |
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Post by garbulky on Aug 5, 2016 23:42:12 GMT -5
^^^^ What is going on here? I think I am lost as usual.  |
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Post by yves on Aug 6, 2016 3:31:58 GMT -5
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Post by Boomzilla on Aug 6, 2016 6:57:45 GMT -5
Please. Don't encourage him. I've learned a ton from his posts; they are factual, free from industry BS, and written in a way that a layman like myself can understand. You're free to skip over them if you wish. No pleasing some people Hi copperpipe - klinemj and jmilton were kidding. We understand & appreciate Keithie's posts. We also have fun with his long-windedness, but no complaint is intended! Boom |
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Post by Boomzilla on Aug 6, 2016 7:03:32 GMT -5
^^^^ What is going on here? I think I am lost as usual. LEDE = "Live End / Dead End" - A philosophy of listening room design that said a room was better balanced by leaving one end with sound absorbers, the other (mostly) without. The goal was to suppress some room reflections, but not all. RFZ = Reflection Free Zone - (borrowed from redspade-audio.blogspot.com/2011/07/rfz-what-it-is-and-why-do-you-need-it.html) - "The concept of a reflection free zone (RFZ) is almost exclusively discussed in studio control rooms, but a similar approach is worth considering in domestic critical listening rooms. The approach is simple. Early strong reflections are reduced but diffuse reflections with a longer time delay are retained. The result is greater image focus and clarity without making a room sound dead. In studios this approach has gained widespread acceptance, but in home audio it is perhaps controversial. According to (Dr. Floyd) Toole (Sound Reproduction), side wall reflections are in fact desirable to create a sense of spaciousness. The size of the image is increased and the overall sound is often enhanced. Most in fact would probably prefer to have side wall reflections. So it is best to consider this concept as one worth understanding and trying, even though it might be something that you prefer..." |
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klinemj
Emo VIPs 
Official Emofest Scribe
Posts: 15,098
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Post by klinemj on Aug 6, 2016 7:28:42 GMT -5
I've learned a ton from his posts; they are factual, free from industry BS, and written in a way that a layman like myself can understand. You're free to skip over them if you wish. No pleasing some people Hi copperpipe - klinemj and jmilton were kidding. We understand & appreciate Keithie's posts. We also have fun with his long-windedness, but no complaint is intended! Boom Yes...and for some, like the one I commented on, it's best to get a fresh, hot, strong cup of coffee and settle into a comfy chair to read. Mark |
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Post by garbulky on Aug 6, 2016 7:47:53 GMT -5
You guys have obviously not read my reviews!  |
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Post by copperpipe on Aug 6, 2016 8:03:10 GMT -5
I've learned a ton from his posts; they are factual, free from industry BS, and written in a way that a layman like myself can understand. You're free to skip over them if you wish. No pleasing some people Hi copperpipe - klinemj and jmilton were kidding. We understand & appreciate Keithie's posts. We also have fun with his long-windedness, but no complaint is intended! Boom Ah, I see, I'm obviously a little humor impaired. It's all good, carry on...  |
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Post by AudioHTIT on Aug 6, 2016 13:02:10 GMT -5
I'm going to correct your terminology here..... You're right, but 1/3 octave RTA helps get your speakers placed and tweaked before playing with EQ, and it can help doing basic EQ settings. FFT gives very detailed information, but is more difficult to work with. I studied acoustics in college and have used a variety of measurement tools beginning with a Sonipulse in the early 70's. I also wrote a paper on the measurements of some high end speakers of the day (Sound Lab, B&W 801,'Beveridge Model 3) - I was able to use the Physics Department's Anechoic Chamber to do sweep, polar, and RTA measurements (Sacramento State had one of the larger chambers in the west). I could then compare the results with in room RTA measurements. It was all very interesting and educational (at least to me if not the rest of the class). I still contend that RTA measurements are useful and the tools are now inexpensive. I also think mine was one of the better answers to the OP's query regarding the "EASIEST software for room measurement (his emphasis). But I don't mind your discussion, however through the lengthy response I'm not sure which terminology of mine you are correcting? |
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Post by AudioHTIT on Aug 6, 2016 13:15:05 GMT -5
I didn't expect you to agree, and of course one can always find examples to the contrary. I have already given you rock solid evidence to support my claim. What do you want more? No point in antagonistic discussion, it has little to do with the OP's question. |
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Post by Axis on Aug 6, 2016 14:16:45 GMT -5
I'm going to correct your terminology here..... I studied acoustics in college and have used a variety of measurement tools beginning with a Sonipulse in the early 70's. I also wrote a paper on the measurements of some high end speakers of the day (Sound Lab, B&W 801,'Beveridge Model 3) - I was able to use the Physics Department's Anechoic Chamber to do sweep, polar, and RTA measurements (Sacramento State had one of the larger chambers in the west). I could then compare the results with in room RTA measurements. It was all very interesting and educational (at least to me if not the rest of the class). I still contend that RTA measurements are useful and the tools are now inexpensive. I also think mine was one of the better answers to the OP's query regarding the "EASIEST software for room measurement (his emphasis). But I don't mind your discussion, however through the lengthy response I'm not sure which terminology of mine you are correcting? Look at the face on that dog. Would he lie ? |
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Post by yves on Aug 6, 2016 18:15:12 GMT -5
I have already given you rock solid evidence to support my claim. What do you want more? No point in antagonistic discussion, it has little to do with the OP's question. There is no antagonistic discussion, but rather, there's the evidence that's still as clear as a bell regardless of whether you want to try to discuss it. |
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For example, most people agree that one half of the room should be live, and the other half should be dead.....Live End, Dead End (LEDE) used to be popular in the 1980s, but designers have shifted away from LEDE rooms. By using the Time Delay Spectrometry (TDS) measurement technique to analyze the time-energy-frequency (TEF), or waterfall plot of a room the Reflection Free Zone (RFZ) criteria can nowadays be applied without anymore requring the LEDE design approach.
