Auricauricle
10-12-2008, 03:08 PM
A recent post I composed described various experiments that I performed on a Yamaha (DSP A-2070) integrated amplifier that I was using for awhile, until I decided my ears were equally happy with a much less assuming Sherwood (R-525) A/V receiver which now occupies the audio cabinet. We live in a rather small apartment, and have had to make various adjustments to make more space available for the various accoutrements that I have acquired in previous years, and stashing the stereo gear into a large Biedemeyer wardrobe trunk is a sacrifice that was not eagerly embraced. I am a man of peace for the most part, but when it comes to my gear, I can get ornery. When my wife insisted that the gear be so stored and that my loudspeakers be placed atop the cabinet, I was deeply hurt. At the time, I owned a very nice Citation 5 tube amplifier and a few other fancy, schmancy things that I wanted to enjoy and show off. In the end, discretion won out, and that is the way it will remain until we move into a bigger apartment or someone has a most unfortunate “accident”.
The experiment that I am talking about involved turning the front speaker attenuators of the Yamaha to the negative, past flat: a step that was in my mind counterintuitive. Although I am quite familiar with sound, my almost compulsive need to tweak and fiddle took the best of me one evening and I found myself aware that the speakers I was listening to (Polk Monitor 7c) were a bit forward in their presentation. As I turned the volume down, I noticed that the perceived placement of the speakers actually descended. By the time I reached a certain point I realised that they had left their perch near the ceiling and sounded as though they were right in front of me--at ear level! To compensate for the diminished volume, as the master volume knob was cranked up, the frontal speaker controls locked in place, an adjustment that continued to give me the sense that the speakers remained in their respective “perceived” places.
Because we live in such a modest abode (okay, and because I am a tweakaholic), I have bought a couple of equalizers that have been employed to help shape the sound of the music I listen to and to assist in compensating for that which the limitation of space imposes. One of them is the Audio Source Architect, a rotary-dialed graphic equalizer that was originally designed for in-wall speaker users who wanted something to maximize their use. The other is a parametric equalizer, an SAE E101, a "computerized " unit that stores ten settings of level, bandwidth and frequency.
Psychoacoustics tells us that amplitude and volume are interrelated but not directly proportional. In other words, a wave that is produced corresponding to a middle C is perceived as louder than a wave that is produced corresponding to a C two octaves lower. This makes sense: when one listens to a music score or watches a movie that involves the use of a subwoofer, the mighty speakers are not heard in uniform correspondence to the higher pitched material. Imagine how horrible it would sound! Instead, some notes are perceived more readily than others. This relationship was made clear in 1933 by Fletcher and Muson, whose despictions of equal loudness contours graphically describe the phenomenon (http://en.wikipedia.org/wiki/Psychoacoustics).
In using the equalizers I have sought to take this knowledge into account and allow the waves that are translated by the speakers a chance to develop somewhat differently than they would if they were allowed to be presented in an unfettered state. Until the experiment was performed, this meant making adjustments that involved clocking the controls to the positive. Intuitively, this made sense. The more directionally positive I turned the controls, I reckoned, the more sound—and satisfaction--I would get. Likewise, clocking backward into the negative territory meant—I reckoned again—subtracting from the musical experience detrimentally.
Remembering my experience with the Yammy, and having way too much time on my hands, I approached the SAE’s controls a bit differently the other day. As previously mentioned, the equalizer has a few controls that are used in shaping sound, among them controls for frequency, bandwidth and level. Until this point, the controls have been turned to the positive end of the spectra, producing satisfactory but fairly predictable listening characteristics. Yet, as I turned the level controls back, I noticed that subtle details popped out of the speakers that I had not expected. In fact, imaging and separation became noticeably improved and by the time the controls were well “to the left” in negative territory, the sound of the speakers I have been listening to was markedly different in quality than before.
I suppose--and fellow readers and physicists, if I am wrong, please correct me--that in turning the controls back, I have created a psychoacoustic equivalent of simulating the full expression of waveforms that would be heard if the space that I had for doing so were to be realized. In so clocking back the controls to less than flat, bass notes are given full bloom and midrange and highs are produced with a bit more clarity and with a little more restraint. I do compensate somewhat in clocking the graphic EQ’s controls a slightly to the positive, thinking that the parametric’s bandwidth control allows me to do so while keeping it all in check.
In sum, while I am listening to music in a way that sounds very pleasant but employs using my equipment in a fashion that is only beginning to make sense. Instead of turning the controls to the usual positive direction, many of them have been set back into the negative, past flat response. In doing so, the waves (as I understand things) are allowed to be produced in their psychoacoustic fullness—much like using a compander of old that allowed loud passages to be made a little louder and the softer passages softer to be reproduced in an exaggerated albeit unexpectedly and pleasantly.
...Anyway, such were the thoughts that came to me this afternoon as I was staring out the window this afternoon and wondering whether the rain was going to let up or I should practice treading water (sorry, BC).
The experiment that I am talking about involved turning the front speaker attenuators of the Yamaha to the negative, past flat: a step that was in my mind counterintuitive. Although I am quite familiar with sound, my almost compulsive need to tweak and fiddle took the best of me one evening and I found myself aware that the speakers I was listening to (Polk Monitor 7c) were a bit forward in their presentation. As I turned the volume down, I noticed that the perceived placement of the speakers actually descended. By the time I reached a certain point I realised that they had left their perch near the ceiling and sounded as though they were right in front of me--at ear level! To compensate for the diminished volume, as the master volume knob was cranked up, the frontal speaker controls locked in place, an adjustment that continued to give me the sense that the speakers remained in their respective “perceived” places.
Because we live in such a modest abode (okay, and because I am a tweakaholic), I have bought a couple of equalizers that have been employed to help shape the sound of the music I listen to and to assist in compensating for that which the limitation of space imposes. One of them is the Audio Source Architect, a rotary-dialed graphic equalizer that was originally designed for in-wall speaker users who wanted something to maximize their use. The other is a parametric equalizer, an SAE E101, a "computerized " unit that stores ten settings of level, bandwidth and frequency.
Psychoacoustics tells us that amplitude and volume are interrelated but not directly proportional. In other words, a wave that is produced corresponding to a middle C is perceived as louder than a wave that is produced corresponding to a C two octaves lower. This makes sense: when one listens to a music score or watches a movie that involves the use of a subwoofer, the mighty speakers are not heard in uniform correspondence to the higher pitched material. Imagine how horrible it would sound! Instead, some notes are perceived more readily than others. This relationship was made clear in 1933 by Fletcher and Muson, whose despictions of equal loudness contours graphically describe the phenomenon (http://en.wikipedia.org/wiki/Psychoacoustics).
In using the equalizers I have sought to take this knowledge into account and allow the waves that are translated by the speakers a chance to develop somewhat differently than they would if they were allowed to be presented in an unfettered state. Until the experiment was performed, this meant making adjustments that involved clocking the controls to the positive. Intuitively, this made sense. The more directionally positive I turned the controls, I reckoned, the more sound—and satisfaction--I would get. Likewise, clocking backward into the negative territory meant—I reckoned again—subtracting from the musical experience detrimentally.
Remembering my experience with the Yammy, and having way too much time on my hands, I approached the SAE’s controls a bit differently the other day. As previously mentioned, the equalizer has a few controls that are used in shaping sound, among them controls for frequency, bandwidth and level. Until this point, the controls have been turned to the positive end of the spectra, producing satisfactory but fairly predictable listening characteristics. Yet, as I turned the level controls back, I noticed that subtle details popped out of the speakers that I had not expected. In fact, imaging and separation became noticeably improved and by the time the controls were well “to the left” in negative territory, the sound of the speakers I have been listening to was markedly different in quality than before.
I suppose--and fellow readers and physicists, if I am wrong, please correct me--that in turning the controls back, I have created a psychoacoustic equivalent of simulating the full expression of waveforms that would be heard if the space that I had for doing so were to be realized. In so clocking back the controls to less than flat, bass notes are given full bloom and midrange and highs are produced with a bit more clarity and with a little more restraint. I do compensate somewhat in clocking the graphic EQ’s controls a slightly to the positive, thinking that the parametric’s bandwidth control allows me to do so while keeping it all in check.
In sum, while I am listening to music in a way that sounds very pleasant but employs using my equipment in a fashion that is only beginning to make sense. Instead of turning the controls to the usual positive direction, many of them have been set back into the negative, past flat response. In doing so, the waves (as I understand things) are allowed to be produced in their psychoacoustic fullness—much like using a compander of old that allowed loud passages to be made a little louder and the softer passages softer to be reproduced in an exaggerated albeit unexpectedly and pleasantly.
...Anyway, such were the thoughts that came to me this afternoon as I was staring out the window this afternoon and wondering whether the rain was going to let up or I should practice treading water (sorry, BC).