sorbe
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Post by sorbe on Oct 13, 2012 21:10:50 GMT -5
Hmm... I totally get the point of absorption for primary reflections in rooms with normal speakers.
But the Mirage OMD line are intentionally "omnidirectional" and the designers claim to "want" to bounce sound off of the walls. I wonder if you're not just making them more like normal speakers by deadening the reflections behind them.
What's the net-net on the sound difference like that?
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Post by spurriersucks on Oct 13, 2012 21:31:02 GMT -5
Hmm... I totally get the point of absorption for primary reflections in rooms with normal speakers. But the Mirage OMD line are intentionally "omnidirectional" and the designers claim to "want" to bounce sound off of the walls. I wonder if you're not just making them more like normal speakers by deadening the reflections behind them. What's the net-net on the sound difference like that? I have asked that question and did a little research and came up with my speakers were too close to the rear wall. I read that if the speakers werecloser than 3' to 4' foot to the rear or sides then panels would be a benefit. I have the behind the speakers but not on the side walls. I haven't had a lot of time with them yet but I don't notice the echo or ringing that I have noticed in the past. |
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jamrock
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Post by jamrock on Oct 14, 2012 7:05:07 GMT -5
Another question I have on this room treatment subject. Are acoustic panels intended only for stereo playback, or for multi-channel playback as well? If so, would we need to do the same experiment (the mirror technique) for each speaker. And would not that cause conflicts with panels for other speakers?
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Deleted
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Post by Deleted on Oct 14, 2012 7:49:24 GMT -5
> Diffusion panels. Most are so alive that there is no room on the walls for the monsterous panels to give a very small notch of the frequency.
Diffusion panels are not a notch filter.
Musicians want reverberation. They want that warm glow of musical persistance to enrich their music; they want hard surfaces to keep the sound bouncing around and they want larger spaces that develop reverberation.
But parallel walls can cause flutter echos, and other reflective surfaces can cause focus (loud) points. Rather that using acoustic panels to absorb the precious reverb, they use diffusion panels to break it up and spread it around.
This is different to modern music recording studios that are acoustically dead; the reverb is added artificially, electronically, later.
Home theaters have no use for diffusion panels. Unlike musicians, we hate reverberation and use acoustic panels to absorb it.
Sincerely
/b
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jamrock
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Post by jamrock on Oct 14, 2012 8:57:12 GMT -5
Thanks for the response. But you have confused me more. If musicians want a reverberant room, why would not hometheater want to capture that experience by also using a reverberant space? I can see why a recording studio would want an anechoic room for proper microphone usage or technique. But isn't "live music experience" the goal of playback? I apologize if I'm asking too many questions and I'm not learning quickly enough  |
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Post by jlafrenz on Oct 14, 2012 9:51:31 GMT -5
Thanks for the response. But you have confused me more. If musicians want a reverberant room, why would not hometheater want to capture that experience by also using a reverberant space? I can see why a recording studio would want an anechoic room for proper microphone usage or technique. But isn't "live music experience" the goal of playback? I apologize if I'm asking too many questions and I'm not learning quickly enough Remember that the space in your home is different from the one that the performance was in. The idea behind acoustic treatments in your home to to give you a room that allows the accurate playback of the material you choose. If the recording was done well it should capture the "live music" experience. Look at it another way. If a recording has a lot of bass in it, you wouldn't want to turn up the bass in your system. |
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Deleted
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Post by Deleted on Oct 14, 2012 9:59:37 GMT -5
> If musicians want a reverberant room, why would not hometheater want to capture that experience by also using a reverberant space?
If I am playing a pipe organ in a church, the reverberation of the church is part of the experiance. Anyone with their eyes closed, can tell if the room is large or small by it's sound. The room reverberation is part of the experiance.
But, if I am listening to a recording of an organ being played, the recording engineer has already captured and encoded the room reverberation in the recording, as a vital part of the recording. If your livingroom acoustic adds (or subtracts) anything to that experiance, it is distortion of the original. You don't want to hear, for example, the boomy resonance at 36hz in your room, caused by a resonance between two wall surfaces in your room.
You want to hear the organ and church; you don't want to hear your room.
Sincerely
/blair
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Post by The Mad Norseman on Oct 14, 2012 11:11:28 GMT -5
Hmm... I totally get the point of absorption for primary reflections in rooms with normal speakers. But the Mirage OMD line are intentionally "omnidirectional" and the designers claim to "want" to bounce sound off of the walls. I wonder if you're not just making them more like normal speakers by deadening the reflections behind them. What's the net-net on the sound difference like that? An excellent question sorbe! Some speakers (like you point out) are intentionally designed to use wide dispersion (especially of high and mid/high frequencies) and to purposely use adjacent surface reflections as part of their 'sound signature'. What absorbing acoustic panels to to those speakers is questionable as to whether its good or bad. I'd recommend you contact your speaker manufacturer's customer service people with that question...and get an informed and specific recommendation that way. |
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Post by Boomzilla on Oct 14, 2012 14:41:59 GMT -5
Does anyone make an online calculator where you can upload your room dimensions, your speaker and listening positions, and show how much room treatment you need & where?
If I can buy an iPhone app that shows what my walls look like if I paint them different colors, then SURELY what I ask for above must be technically feasible?
Thanks - BZ
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Post by ansat on Oct 14, 2012 15:05:21 GMT -5
Does anyone make an online calculator where you can upload your room dimensions, your speaker and listening positions, and show how much room treatment you need & where? If I can buy an iPhone app that shows what my walls look like if I paint them different colors, then SURELY what I ask for above must be technically feasible? Thanks - BZ sent from my phone. sorry for the short response. Tony |
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Post by AudioHTIT on Oct 14, 2012 15:16:43 GMT -5
Some speakers (like you point out) are intentionally designed to use wide dispersion (especially of high and mid/high frequencies) and to purposely use adjacent surface reflections as part of their 'sound signature'. What absorbing acoustic panels to to those speakers is questionable as to whether its good or bad. Ha! The Bose 901 comes to mind. Some will remember 8 of the 9 5" drivers pointed away from the listener and were intended to be reflected. As I remember Dr. Bose measured a concert hall and deduced that 8/9th's of the sound that reached the listeners ear was reflected, therefor he designed his speakers that way - many people bought it ... or them. With enough power they could have a big sound that was sometimes impressive, but not necessarily accurate; they sure helped large amp sales. |
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jamrock
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Post by jamrock on Oct 14, 2012 16:10:11 GMT -5
> If musicians want a reverberant room, why would not hometheater want to capture that experience by also using a reverberant space? If I am playing a pipe organ in a church, the reverberation of the church is part of the experiance. Anyone with their eyes closed, can tell if the room is large or small by it's sound. The room reverberation is part of the experiance. But, if I am listening to a recording of an organ being played, the recording engineer has already captured and encoded the room reverberation in the recording, as a vital part of the recording. If your livingroom acoustic adds (or subtracts) anything to that experiance, it is distortion of the original. You don't want to hear, for example, the boomy resonance at 36hz in your room, caused by a resonance between two wall surfaces in your room. You want to hear the organ and church; you don't want to hear your room. Sincerely /blair I am not a friend of the so called Venue Acoustic Signature (my terminology). Because they never sound right. Although some reported that Yamaha has done quite a commendable job in recreating the acoustic signatures of certain venues. I'm yet to come across one that I find satisfactory. I believe that when a musical instrument is played and captured uncolored by the venue (closed mic), it will give the impression of a live playback in any room. However, when the acoustic signature of a venue is captured and is played back in another room, it always sound artificial. Live playback relies on the reflective properties of the room to create natural ambience, I believe. That is why I am asking questions about the use of acoustic panels. If it is good for all playback situations, or is it dependent on the goal of the listener |
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Post by laserman35 on Oct 15, 2012 7:11:52 GMT -5
For playback of music i prefer a heavy sound deaden rooms.
Now for live performance i would want a room with great acoustics.
I want to hear what the sound engineer listened to, not how a room changes the sound of the recording.
Sound engineers do very in how much sound absorption the put in there playback room, so i guess it's a matter of taste.
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Post by Boomzilla on Oct 15, 2012 8:03:39 GMT -5
THANKS, Tony! That was EXACTLY what I was looking for. Now I've got to overcome the dreaded "spouse acceptance factor." |
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Post by jlafrenz on Oct 15, 2012 18:26:46 GMT -5
THANKS, Tony! That was EXACTLY what I was looking for. Now I've got to overcome the dreaded "spouse acceptance factor." Picture panels. Let her pick the artwork. |
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Post by spurriersucks on Oct 20, 2012 21:10:31 GMT -5
Panel behind my center is up now.  |
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Post by Boomzilla on Oct 20, 2012 21:51:31 GMT -5
...If musicians want a reverberant room, why would not hometheater want to capture that experience by also using a reverberant space?... Hi Jam - I'd like to take a shot at answering your question. For acoustic recordings, the echoes of the performance space are already in the recording (its own venue). If your room then adds echo, you're overlaying EVERYTHING that you play with "the sound of your room." To best hear the original recording venue, it is advisable NOT to allow your room to "sing along with the music." For home theater, the same applies. If the Foley engineer wanted you to hear an approaching tank on the battlefield from the rear, then the tank should sound like it's on the battlefield, not on the rear wall of your room. In theory, and with the exception of dipolar, bipolar, and omnidirectional speakers (that ARE intended to play in your room), the recording engineer's intent is that you hear the "first arrival" of sound waves from your speaker without the overlay of your room's echoes. I may have explained this less than clearly - does it make sense to you? Cordially - Boomzilla |
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Post by yves on Oct 21, 2012 5:24:49 GMT -5
I was under the impression that all/most reflection was undesirable; wrong? Too much absorption will make a room sound "dead", but absorption is still the one best way to eliminate first order reflections. Think of each flat surface (the walls, the floor, the ceiling,...) as a mirror. You can simulate this by placing a small mirror against a flat surface in your room. If you can see the reflection of one of your speakers in the mirror while sitting at your listening position, that means the mirror is in a spot where a first order reflection occurs, and that's where absorption should be used. The back side of an absorption panel can absorb too, so leaving a bit of space between it and the wall behind it can help. Once the first order reflection points have been dealt with, you can try to figure out where the sound keeps bouncing back and forth between opposing surfaces. Imagine a straight line coming from one of your speakers. Imagine the line is perpendicular to the wall your speaker is pointed at. The sound of your speaker bounces back, off of this wall, back to the wall behind your speaker. Similarly, it will bounce back and forth between side walls, and between the ceiling and floor. This effect can be mitigated, if necessary, using diffusion. If the room sounds too "dead", it can be made to sound more "live", using a mixture of small patches of reflection and diffusion in an alternating fashion, e.g. resembling a checkerboard. An alternative way of combining reflection and diffusion can be achieved using a curbed hard surface, or alternating strips of reflection and diffusion placed next to oneanother at different angles. Reflectors and diffusors are not always needed, and even if it does help, it isn't needed in very large quantities, it varies with the characteristics of the room, furniture placement, materials used, etcetera. The easiest way to find out a strategic place to apply diffusion is through careful experimentation and using common sense. A large reflective surface in a room usually has a negative impact on sound. A hard floor is best because the reflections on it are in line with how the sound would normally travel during a live performance. However, placing a rug in front of each speaker will help to soften the hard reflections. |
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Deleted
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Post by Deleted on Oct 21, 2012 12:52:44 GMT -5
I've heard a lot about "first order" reflections. Is there a such thing as "second", and maybe even "third order" reflections? I understand the logic of using the "mirror method" for finding the first order. But not a method for finding the "second order" or beyond. It seems to me for finding the "second order" reflection point you could use a laser pointing light, and from where the speaker is, point the laser back at the mirror you just positioned to determine the "first order" reflection. You would hypothetically see the next reflection point by seeing where the "red dot" is reflected to, and place a panel there. But what is the real method for determining other "order" reflection points?
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Post by monkumonku on Oct 21, 2012 14:49:58 GMT -5
I've heard a lot about "first order" reflections. Is there a such thing as "second", and maybe even "third order" reflections? I understand the logic of using the "mirror method" for finding the first order. But not a method for finding the "second order" or beyond. It seems to me for finding the "second order" reflection point you could use a laser pointing light, and from where the speaker is, point the laser back at the mirror you just positioned to determine the "first order" reflection. You would hypothetically see the next reflection point by seeing where the "red dot" is reflected to, and place a panel there. But what is the real method for determining other "order" reflection points? But if you effectively reduce the 1st order reflection points, then perhaps the following reflection points would not be a significant factor in influencing the sound because the buck would stop at the 1st point. |
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