I'm sorry Lou but, I can be rather "basic" in my understanding about some aspects of audio reproduction. What do they do, for whom - what condition might they be needed? I'm assuming booming resonance in corners? If/when I ever get that, it's only when playing vinyl at high, high volumes (which I rarely use). I won't get any of that with my CD player.
Let me address your basic understanding from a different angle. The human ear locks in on the loudest (highest amplitude) sound for both location and understanding. When there are two sources (or more) of a sound, understanding may be difficult and it's location undetectable. Thus, when you are trying to talk across a gymnasium, for example, it is difficult to both understand and to know where the sound is coming from. As you walk closer to each other, there will become a moment when both "lock" in. That is because the direct sound (speech) is louder than the first reflections. In both stereo and home theater, there is a steering logic. In stereo, it is provided by the difference in the arrival time of the sound recorded. In home theater, this is also true but there is also intentional delays to create the effects of things moving sonically. Where devices like ASC tube traps and others come into play is dealing with these reflections or imbalances in frequencies affecting both the clarity and location of the sound. The most common ones addressed are known as first reflections. Think of sound coming out of the speaker and bouncing off the side wall like a billiard ball hitting the first rail. Thus, some form of control is used at that point to reduce (absorb) the amplitude of that signal. It is easy to find these points by sitting in your listening position and having someone move a mirror down the side walls until you can see the face of the speaker reflected in the mirror. That's a first reflection point. What many people forget, by the way, is that the same thing happens off of ceilings and floors. Where devices like the ASC Traps come into play, which by the way was first created by Bell Laboratories, is providing a variable adjustment to the absorption or reflective needs. This is done by a tube with a slot in it and depending upon the specific frequency range targeted, the trap diameter changes. Smaller diameters address higher frequencies than say large diameter ones. Conversely, the larger the diameter, the less effective they are at higher frequencies. This is because each frequency has a known length to form a complete wave. Flat panel devices, say office dividers, are very narrow in the range they work and there is no changing their effect. That's why such things are used in call centers so that you don't hear other voices. Does their "effect" depend upon volume? Not really although volume may make it more obvious. But rooms full of reflections usually disrupt both the sense of stereo imagery and the steering of sound in home theaters. Many original THX certified speakers, for example, specifically controlled vertical dispersion to avoid reflections off the ceiling (principally) or the floor. In theaters, it is quite common to have some form of damping material on the side walls to avoid those first reflections for any location in the theater. The biggest risk of such devices is a combination of over-damping a room and/or not addressing the right frequency where the problem exists. In a funny sort of way, that's why many equalizers in home usually looked like a smile. They knew they had a problem but did not know how to fix it and sometimes it is the room itself. Going about it without understanding what is wrong is like constantly adding things to a soup where you end up with a large pot is distasteful goo. Hope this helps you see (hear) the picture a bit better. Thanks for the question.
@ Outstanding answer! And very thorough. I think I get it! I’m aware of my side wall first reflection. In my listening room the left channel has nothing but a curtain off of which to reflect. The right channel side wall first has a “vent”, as there’s a small French door, a foot to three, when open. Just going back to my original question; being familiar to an extent with all reflections, I believe this is why I stay away from rear- ported speakers and perhaps why I like my Tannoy’s, with their down firing into a plinth designed to fire forward. And least that’s my belief.
@@zizendorf Well, I had written an answer but since I have sweaty palms and a track pad, it went blip before I could save it. So, my second answer was perhaps more polished. Glad you liked it. Personally, I have had my share of experiences with ports and in some cases, added bungs to reduce their effect much to the improvement to the speaker. Not too familiar with the downward approach other than with subwoofers. So, if it works for you, then it is success.
@@zizendorf By the way, your original question and my answer will be published as my January blog. That's why I like questions because they are always food for thought and ideas.
@@audibleeleganceinc Yes, the Tannoy Revolution XT-8F has a tuned port for the lower woofer, sealed from the upper concentric driver - tweeter/mid-bass. And, I do have the "bungs" in place. (Don't care for that noun.)
I'm sorry Lou but, I can be rather "basic" in my understanding about some aspects of audio reproduction. What do they do, for whom - what condition might they be needed? I'm assuming booming resonance in corners? If/when I ever get that, it's only when playing vinyl at high, high volumes (which I rarely use). I won't get any of that with my CD player.
Let me address your basic understanding from a different angle. The human ear locks in on the loudest (highest amplitude) sound for both location and understanding. When there are two sources (or more) of a sound, understanding may be difficult and it's location undetectable. Thus, when you are trying to talk across a gymnasium, for example, it is difficult to both understand and to know where the sound is coming from. As you walk closer to each other, there will become a moment when both "lock" in. That is because the direct sound (speech) is louder than the first reflections.
In both stereo and home theater, there is a steering logic. In stereo, it is provided by the difference in the arrival time of the sound recorded. In home theater, this is also true but there is also intentional delays to create the effects of things moving sonically. Where devices like ASC tube traps and others come into play is dealing with these reflections or imbalances in frequencies affecting both the clarity and location of the sound. The most common ones addressed are known as first reflections. Think of sound coming out of the speaker and bouncing off the side wall like a billiard ball hitting the first rail. Thus, some form of control is used at that point to reduce (absorb) the amplitude of that signal. It is easy to find these points by sitting in your listening position and having someone move a mirror down the side walls until you can see the face of the speaker reflected in the mirror. That's a first reflection point. What many people forget, by the way, is that the same thing happens off of ceilings and floors.
Where devices like the ASC Traps come into play, which by the way was first created by Bell Laboratories, is providing a variable adjustment to the absorption or reflective needs. This is done by a tube with a slot in it and depending upon the specific frequency range targeted, the trap diameter changes. Smaller diameters address higher frequencies than say large diameter ones. Conversely, the larger the diameter, the less effective they are at higher frequencies. This is because each frequency has a known length to form a complete wave. Flat panel devices, say office dividers, are very narrow in the range they work and there is no changing their effect. That's why such things are used in call centers so that you don't hear other voices.
Does their "effect" depend upon volume? Not really although volume may make it more obvious. But rooms full of reflections usually disrupt both the sense of stereo imagery and the steering of sound in home theaters. Many original THX certified speakers, for example, specifically controlled vertical dispersion to avoid reflections off the ceiling (principally) or the floor. In theaters, it is quite common to have some form of damping material on the side walls to avoid those first reflections for any location in the theater.
The biggest risk of such devices is a combination of over-damping a room and/or not addressing the right frequency where the problem exists. In a funny sort of way, that's why many equalizers in home usually looked like a smile. They knew they had a problem but did not know how to fix it and sometimes it is the room itself. Going about it without understanding what is wrong is like constantly adding things to a soup where you end up with a large pot is distasteful goo.
Hope this helps you see (hear) the picture a bit better. Thanks for the question.
@ Outstanding answer! And very thorough. I think I get it! I’m aware of my side wall first reflection. In my listening room the left channel has nothing but a curtain off of which to reflect. The right channel side wall first has a “vent”, as there’s a small French door, a foot to three, when open.
Just going back to my original question; being familiar to an extent with all reflections, I believe this is why I stay away from rear- ported speakers and perhaps why I like my Tannoy’s, with their down firing into a plinth designed to fire forward. And least that’s my belief.
@@zizendorf Well, I had written an answer but since I have sweaty palms and a track pad, it went blip before I could save it. So, my second answer was perhaps more polished. Glad you liked it. Personally, I have had my share of experiences with ports and in some cases, added bungs to reduce their effect much to the improvement to the speaker. Not too familiar with the downward approach other than with subwoofers. So, if it works for you, then it is success.
@@zizendorf By the way, your original question and my answer will be published as my January blog. That's why I like questions because they are always food for thought and ideas.
@@audibleeleganceinc Yes, the Tannoy Revolution XT-8F has a tuned port for the lower woofer, sealed from the upper concentric driver - tweeter/mid-bass. And, I do have the "bungs" in place. (Don't care for that noun.)