Monday, December 18, 2006

Andy Chaney, Pieper Final Post

note:all recordings have been slowed down to 5% of their original speed

What Rob and myself talked about in terms of what to do for the final analysis revolved around the fact that I had to slow down all of the recordings so that I could hear them (I'm hearing impaired, mostly in
the high frequencies). What this did, then, was created some interesting conditions in the sound recordings, such as the large amounts of sustain, which I gauged to be the most accurate aspect of what kind of space was coming across in the recording. Thus, Rob suggested to do a test with several sonograms of the same ding but from different positions, in order to sort of study the waveform and types of frequences each rig was picking up, as well as looking at how each frequency sustained with the rig. Below, you can see three of the tests that I thought really had a nice amount of sustain, which was test 3. I chose station 3 (my own), 7, and 10, and did sonograms on those stations. If you look below, you can see each rig, and the resulting sonogram that each had, as well as listening to the recording, too.

Picture of Test 3, Station 3 Rig compared against the Sonogram For Test 3, Station 3. 12 O'Clock Ding.

Listen to the slowed down recording of Test 3, Station 3
(Click on "download full URL" to download the mp4 file)

Picture of the Test 3, Station 7 rig, compared to the Sonogram for Test 3, Station 7. 12 O'Clock

Listen to the slowed down recording from Test 3, station 7

Picture of the Test 3, Station 10 Rig compared to the Sonogram for Test 3, Station 10, 12 O'Clock Ding

Listen to the slowed down recording from Test 3, Station 10

Where this test seems to hold the most promise is in terms of how the rigs performed according to what they were showing in terms of the frequency response. A quick note about the sonograms: what they represent is each frequency, high and low, and how long they were still showing a response. The higher up on the chart, the higher the frequency, as you can see on the sonograms. In terms of the results of this test, #3 and #7 performed much better than #10 did. As you can see on the sonogram above, #3 and #7 had very good responses across all of the frequencies, and they seemed to sustain much better, judging by the longer responses than on #10. #10 had very "thin" responses even in the initial part of the sonogram, I don't know if this meant that the sounds were not picked up very well by the microphone, but looking at the sonogram, they don't seem as strong as the ones in #3 and #7. I noticed that in #3, some of the mid-frequencies seemed to hold almost until the end, and the higher frequencies had a nice response. This sort of feels consistent with my initial observations about why I liked those recordings in the first place, because of the interesting sustain that they captured. I described it as feeling as if the sounds were being held by the microphone and the rig even after the initial sounds had passed. It gave the room a weird localization. #7 had similar characteristics in its sonogram as #3 did, although the sonogram got cut off a little bit at the end during the transfer process to blogger. #10 just didn't seem to sustain as well as the other ones did, and perhaps that was indicative of the rig type, where the other two were parallel boundaries and probably had a little bit of the sound being contained, or bouncing off the rigs, #10 did not have the same rig characteristics, and that seems to be reflected in the test. Also, I didn't notice any specific variations in this test because of it, but I intentionally chose ones that had a baffle, or that didn't have a baffle, so that I could contrast the parallel boundary sonograms with a baffle, and a parallel boundary without a baffle, etc. And then a rig without the parallel boundary, but with a baffle. However, I couldn't really discern any specific results in terms of the baffle or no baffle, I thought it might show a different type of frequency sustain, but it wasn't really reflected in the test.


us said...

Hi Andy--

According to the test sheet, your first sample (test3-sta3) is an ORTF omni rig separated 21" with a baffle. Your second sample is a Parallel Boundary rig with 3" inset and the third rig is a pair of Front-Facing omni mics separated 13" with a Large Baffle in between.

To help discern more from the tests, did you select the 12 o-clock strike from each sample and make the sonograms from one or both stereo channels? As long as the same strike was used, its okay.

Perhaps if you used just one of the stereo channels from each rig that would show more precision. (Amadeus can import a stereo file as dual mono, just use one channel and close the other.)

Also, consider the location of the rigs in relation to each other in trying to explain the dfference between station #10 and the others.

Unfortunately, I can't listen to your sound files or see your sonograms at the moment. Perhaps you need to grant WWW read status to your host account? Rob D.

us said...

Hi Andy--

OK, just a quickie. I made three sonograms which I'll email you and you can look at them. What I did that was different from you was match the gain of the impulses on all three so any volume differences were removed. Also made them the exact same duration (12 secs)

To my eye, the sonograms are very close in appearance. I feel I can dicern more differences between the three mic stations/sounds received via my ears than using clues from the high resolution sonograms. I tried to make a movie to animate the changes but the registration was messed-up. No time to re-do now.

My summaary is: Ears 3, Eyes 1. It was a fun game to play, but the ears are still champs when it comes to finding and interpreting differences

PS. Your links to Pantherfile are very atypical. I'd consider opening your own Blogger account and practice following the steps in my or their tutorials again. You seem to have gotten-off the usual path. Rather than backing-out, it might be easier to start over following the tutorials again step for step. Congrats on hanging in there, you'll master it. Rob D.