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Thread: How well do your Sierra-2’s image? LEDR test?

  1. #11
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    Default Re: How well do your Sierra-2’s image? LEDR test?

    Quote Originally Posted by djDANNY View Post
    Well I've gone ahead and retried the test with the "equilateral triangle" listening position as was suggested. I also folded up the baby gate out of the way so that no one would accuse it of messing up the test. The test was run both with the speakers pointing straight ahead and with the speakers toed-in. With that said, I'm still not able to get any depth or vertical imaging from the test. I get perfectly fine/smooth left to center to right imaging, but I get nothing from the test sounds that should show a sense of height or depth.

    I'm hoping someone with Sierra 2's (or 2-EX) could confirm that they are able to get height and depth imaging from their speakers. So far, it doesn't seem like anyone has been able to get that type of imaging from these speakers. I'm willing to try to fix my setup but before I spend hours upon hours (and dollars upon dollars) I'd like to know that these speakers are able to produce height and depth imaging. I know the ribbon tweeters have very limited vertical dispersion so not sure if that affects the "height" imaging.

    From the description of the test, it seems like it might be somewhat based on ear shape so maybe my ear just isn't shaped correctly for this test. Alternatively, does anyone have any examples of songs that should show off height and/or depth imaging that I can use to test?
    Hi Danny,

    Tests like these are very complex and rarely ever work as advertised, this one in particular uses a pinna transform. I was actually part of a research project many decades ago that was assigned to the head of the engineering dept at the company I worked for at the time. The way these are typically done is that a mannequin head is used and outer ears (pinna) are attached to the head. A specialized small capsule microphone is placed in each ear and then a highly directional speaker is used to move around the mannequin head - typically 360 degrees around the head in every possible direction - and then again at a different distance. Sine wave seeps or a maximum length sequence signal is generated from the speaker and then the signal received by each microphone is recorded and then transformed into a frequency response.

    From this data, one can then make timing and frequency response changes to a left/right stereo signal to simulate what is "heard" which corresponds to a specific position in space based on what I mentioned above.

    Directionality is due to having binaural hearing, the ability to hear separate sounds in both ears. It is subtle changes in frequency response and timing from one ear to another that allows our brain to determine a direction. It is something our brain subconsciously learns as soon we start hearing. It is very subtle.

    The assumption of, are these speakers capable of reproducing height and depth with this test, is wrong. It isn't whether or not the speakers can, it is whether or not your pinna and the acoustical environment of your room is close enough to what was used when the transform was created.

    Looking at your room, it is full of reflections. A reflection is when sound will bounce off a surface. This reflected sound is not necessarily bad, but it will dramatically change the frequency response and timing of the original signal - thus completely throwing off the various spatial cues. In addition, the shape and size of your head, the separation distance between your ears and most importantly, the shape of your pinna - all must be quite similar to the mannequin head or your brain won't translate the intended directionality properly.

    I know the ribbon tweeters have very limited vertical dispersion so not sure if that affects the "height" imaging.
    Not in the least, in fact - it helps with vertical height as it limits unwanted reflections - which is precisely the reason so many speakers are designed specifically for controlled vertical dispersion.

    We don't actually hear sounds that are above or below us, or to the left or right - sound waves hit our eardrums all at the same direction. Our brain determines direction by using our very own built in HRTF, otherwise know as a head related transfer function.

    In simper terms, the Sierra-2 and Sierra-2EX are extremely accurate speakers and easily able to reproduce the subtle changes in frequency response and timing necessary for proper imaging. In the case of what you are experiencing with that ledr test, the environment and possibly your pinna are simply not a close enough match to the HRTF transform generated by the original equipment.

    Back to the project I enjoyed being a part of, which I believe was an early version of QSound. Very few of us heard the intended directionality - in fact, it was interesting because those of us who were younger had better results ( I was young back then ) We had better results when the speakers were placed in a highly treated sound room (very few reflections) and positioned in a perfect equilateral triangle, with a listening distance of 1 meter. Even then, I recall slightly less than 50% of us were able to properly place the sounds - for which we then correlated that those with smaller outer ears had more accurate results than those with larger outer ears. We suspected that the original HRTF was developed using smaller outer ears...

    That was a fun week for a few of us and some good memories for me.

    I'm rambling - but hopefully I made some sense.
    .
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

  2. #12
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    Default Re: How well do your Sierra-2’s image? LEDR test?

    I played around with the samples for that test yesterday and I'm happy to report that my Sierra 2s passed with flying colors!

  3. #13
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    Mar 2019
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    Default Re: How well do your Sierra-2’s image? LEDR test?

    Thanks Dave for the lengthy explanation and background. I’m very happy that I was able to find some material (Yosi Horikawa) that really had extreme imaging that showed off what the Sierra’s could do despite what I couldn’t hear from the LEDR test. Been very happy with these speakers and feel more reassured now that they’re not “missing something”.

  4. #14
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    Apr 2020
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    Default Re: How well do your Sierra-2’s image? LEDR test?

    Quote Originally Posted by djDANNY View Post
    Thanks Dave for the lengthy explanation and background. I’m very happy that I was able to find some material (Yosi Horikawa) that really had extreme imaging that showed off what the Sierra’s could do despite what I couldn’t hear from the LEDR test. Been very happy with these speakers and feel more reassured now that they’re not “missing something”.
    For the LEDR test, it is very finicky with placement, toe-in, distance, etc.. I put a lot of time into optimizing my layout as best as I can for best performance. My S2s make nice triangle with MLP, are over 3' from any corners and 2' from the front wall so there's room for them to open up. Looking at your photo I can see some compromises had to be made that could affect your results, but we work with what we have. Mine isn't perfect either, but my young 'un is out of the house so I don't need to kid proof anymore!

    Anyhoo, I got good results but it took careful placement and positioning. I had my wife sit in the MLP and close her eyes while I cycled through the samples without telling her what to listen for. When we got to "behind" she thought the rear speakers were on! I heard it too. It fascinates me how the mind can be fooled like that. Just by changing phase and frequency.

  5. #15
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    Mar 2019
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    Default Re: How well do your Sierra-2’s image? LEDR test?

    Quote Originally Posted by Pogre View Post
    For the LEDR test, it is very finicky with placement, toe-in, distance, etc.. I put a lot of time into optimizing my layout as best as I can for best performance. My S2s make nice triangle with MLP, are over 3' from any corners and 2' from the front wall so there's room for them to open up. Looking at your photo I can see some compromises had to be made that could affect your results, but we work with what we have. Mine isn't perfect either, but my young 'un is out of the house so I don't need to kid proof anymore!

    Anyhoo, I got good results but it took careful placement and positioning. I had my wife sit in the MLP and close her eyes while I cycled through the samples without telling her what to listen for. When we got to "behind" she thought the rear speakers were on! I heard it too. It fascinates me how the mind can be fooled like that. Just by changing phase and frequency.
    Glad it worked for you. I’m not sure how much I can do to treat the room. The left side is all giant bay windows that I can’t put treatment on. The right side actually has a double door opening where the first reflection point would likely be. I’m not convinced any treatment behind the speakers would do too much but I’m not an expert on that by any means.

    For the “behind” test, isn’t that supposed to simulate the sound coming from behind the front speakers, not from behind you?

    Either way, I’m glad that I’ve been able to find some material that allowed me to hear the depth and height imaging from the speakers. If you get a chance, I suggest listening to two songs in particular from Yosi Horikawa. “Stars” in the beginning has these bird (or something like that) sounds that seem to be coming from the far upper left (almost like coming from outer space). “Bubbles” has these ping pong balls that sound like they were bouncing up and down on my floor. It sounded extremely realistic. I don’t know how he mixed those to get that type of imaging but I was pretty amazed.

  6. #16
    Join Date
    May 2015
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    Default Re: How well do your Sierra-2’s image? LEDR test?

    What about curtains on the bay windows?
    Alternately, GIK (and probably others) make free-standing acoustical panels.

  7. #17
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    Default Re: How well do your Sierra-2’s image? LEDR test?

    Quote Originally Posted by racrawford65 View Post
    What about curtains on the bay windows?
    Alternately, GIK (and probably others) make free-standing acoustical panels.
    I have honeycomb blinds covering the windows but not sure how much those help with reflections. Free standing panels would be a no go with kids running around and they would essentially block the windows anyways. I think I’m pretty much stuck with what I’ve got in my living room arrangement unfortunately.

  8. #18
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    Apr 2020
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    Default Re: How well do your Sierra-2’s image? LEDR test?

    Quote Originally Posted by djDANNY View Post
    Glad it worked for you. I’m not sure how much I can do to treat the room. The left side is all giant bay windows that I can’t put treatment on. The right side actually has a double door opening where the first reflection point would likely be. I’m not convinced any treatment behind the speakers would do too much but I’m not an expert on that by any means.

    For the “behind” test, isn’t that supposed to simulate the sound coming from behind the front speakers, not from behind you?

    Either way, I’m glad that I’ve been able to find some material that allowed me to hear the depth and height imaging from the speakers. If you get a chance, I suggest listening to two songs in particular from Yosi Horikawa. “Stars” in the beginning has these bird (or something like that) sounds that seem to be coming from the far upper left (almost like coming from outer space). “Bubbles” has these ping pong balls that sound like they were bouncing up and down on my floor. It sounded extremely realistic. I don’t know how he mixed those to get that type of imaging but I was pretty amazed.
    I didn't do any room treatments. My room is kinda goofy too tho, with a sliding glass door to the left and another room with an open arch to the right. There's a window behind each speaker too, vaulted ceilings and a hallway. Curtains, blinds, carpeting and puffy furniture ftw! lol.

    I wouldn't sweat it too much, these are fantastic speakers. I've had many sets of speakers come through my living room and none of them have grabbed me like the S2s. I like them so much I ordered the ribbon towers! I'll bet if you remove the child gate, pull your speakers out more, toe them in just so and sit closer you could get it to work for you. You really have to be sitting in the right spot and have everything as close to ideal as possible. If I tweak the toe in on one of my speakers even a tiny bit the whole illusion falls apart.

    Another thing too, while listening I'm reminded of those drawings that look like one thing, but when you concentrate you can see a completely different image. Like this "Old Woman or Young Woman" image.

    miss-big.jpg

    Once you see it both ways, you can switch between them with a little concentration. I think there are some similarities with the way that image works on your brain and this test. I'm sure there's some expectation bias happening on my end and it's enough to tip my brain the rest of the way. Just like the image. If you're prepped beforehand you're more likely to see it.

    All that said, I can see why stuff like this could drive Dave crazy, lol. I think a lot of folks just expect it to work without taking all of the minutiae into consideration.
    Last edited by Pogre; 05-28-2020 at 12:07 PM.

  9. #19
    Join Date
    Feb 2017
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    5

    Default Re: How well do your Sierra-2’s image? LEDR test?

    I don't know anything about the LEDR test, but I've been using the Roger Waters test for setting up my speakers for a few years now. Dave mentioned it earlier with the development of Q Sound. The album Amused to Death was recorded in Q Sound and the track Three Wishes is what I have used to position my speakers over the years. If positioned correctly (with the right room treatments), the into will have a surround sound effect where the voices will be coming from your left shoulder.

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