Update: Today I performed the close-up speaker measurements.
I moved the speaker being measured close to the center of my living room/listening room, with the Persian rug you can see in my system description photos folded back roughly in half. That resulted in the front baffle of the speaker being located 10.5 feet from the large window on the front wall (i.e., the wall behind the speaker). The speakers left side was located about 5 feet from the fireplace on the left. Its right side was located about 7 feet from the right wall, but just 4.5 feet from the large mahogany antique radio/phono console you can see along the right wall in my system description photos (the thing that looks like a Chippendale-style bureau, which Im pretty certain weighs in the area of 350 to 400 pounds, and which I therefore wasnt about to move. Its shipping weight in the large wooden crate in which it was sent to me about 20 years ago was 567 pounds!). The distance to the rear wall, the middle third of which is an opening to another room, was around 11 feet. I positioned the mic at a height of 30 inches, which placed it exactly between the heights of the two closely spaced tweeters on my speakers. When I measured each speaker, I moved the other speaker a few feet to the side of its normal position, to get it as far away as possible from the speaker being measured. I placed pillows on the rug between the speaker being measured and the microphone. I closed all the windows so that the mic wouldnt pick up bird chirping and other outdoor sounds, and I turned off all noise-making appliances that were within earshot. Fortunately a noisy rainstorm didnt start until a few hours after I finished with the measurements.
I made a total of 9 measurements on each speaker, three different distances (2.5 feet, 3 feet, 3.5 feet), times three setup conditions (no acoustic panels, two large double-section acoustic panels surrounding the microphone on three sides and projecting somewhat forward of it, and the same acoustic panels re-positioned to surround the speaker on three sides and project somewhat forward of it).
Each of the 9 measurements of each speaker consisted of a 2.4 second sweep repeated 9 times, with the sample rate set to its 96 kHz default setting (2.4 seconds being the longest sweep time choice that appeared to be offered at the 96 kHz sample rate). I adjusted the volume such that peaks were indicated in the DEQX software as being 102 to 104 db, which my speakers and amp can handle comfortably (even at listening distances). I wore a professional quality hearing protector (the kind designed for use with outdoor power equipment) during the measurements. The software indicated a confidence level of about 38 db on each of the 18 measurements.
All of this took a bit more than 4 hours, most of which of course involved moving and replacing the speakers, and setting up the mic, computer, acoustic panels, etc.
After viewing the impulse response plots corresponding to each of the measurements (on a much larger screen than my laptop provides), as I had suspected the ones taken with the acoustic panels surrounding the microphone were clearly the best, with the ones taken with the panels surrounding the speaker also being significantly better than the ones taken with no panels in place. The 2.5 foot measurements looked a bit better than the 3 foot measurements, which in turn looked a bit better than the 3.5 foot measurements. But Im inclined to go with the 3 foot measurements due to the concern I expressed earlier in the thread about timing artifacts resulting if very close-up measurements are used, given the somewhat wide spacing of the drivers on my speakers.
The next step will be to generate speaker corrections in the software, utilizing those measurements. Ill probably create two sets of corrections, one conservative and one somewhat aggressive, and upload them to separate profiles on the DEQX. Ill then evaluate the resulting sonics with a variety of recordings, before attempting any room corrections. My next significant update is likely to be several days or more from now.
Finally, Ill mention that Nyal (AcousticFrontiers), from whom I purchased the HDP-5, was kind enough to contact me the other day to see how I was doing with it, and graciously offered to review and comment on my DEQX project file. Ill probably take him up on that in the coming days or weeks.
Best regards,
--Al
I moved the speaker being measured close to the center of my living room/listening room, with the Persian rug you can see in my system description photos folded back roughly in half. That resulted in the front baffle of the speaker being located 10.5 feet from the large window on the front wall (i.e., the wall behind the speaker). The speakers left side was located about 5 feet from the fireplace on the left. Its right side was located about 7 feet from the right wall, but just 4.5 feet from the large mahogany antique radio/phono console you can see along the right wall in my system description photos (the thing that looks like a Chippendale-style bureau, which Im pretty certain weighs in the area of 350 to 400 pounds, and which I therefore wasnt about to move. Its shipping weight in the large wooden crate in which it was sent to me about 20 years ago was 567 pounds!). The distance to the rear wall, the middle third of which is an opening to another room, was around 11 feet. I positioned the mic at a height of 30 inches, which placed it exactly between the heights of the two closely spaced tweeters on my speakers. When I measured each speaker, I moved the other speaker a few feet to the side of its normal position, to get it as far away as possible from the speaker being measured. I placed pillows on the rug between the speaker being measured and the microphone. I closed all the windows so that the mic wouldnt pick up bird chirping and other outdoor sounds, and I turned off all noise-making appliances that were within earshot. Fortunately a noisy rainstorm didnt start until a few hours after I finished with the measurements.
I made a total of 9 measurements on each speaker, three different distances (2.5 feet, 3 feet, 3.5 feet), times three setup conditions (no acoustic panels, two large double-section acoustic panels surrounding the microphone on three sides and projecting somewhat forward of it, and the same acoustic panels re-positioned to surround the speaker on three sides and project somewhat forward of it).
Each of the 9 measurements of each speaker consisted of a 2.4 second sweep repeated 9 times, with the sample rate set to its 96 kHz default setting (2.4 seconds being the longest sweep time choice that appeared to be offered at the 96 kHz sample rate). I adjusted the volume such that peaks were indicated in the DEQX software as being 102 to 104 db, which my speakers and amp can handle comfortably (even at listening distances). I wore a professional quality hearing protector (the kind designed for use with outdoor power equipment) during the measurements. The software indicated a confidence level of about 38 db on each of the 18 measurements.
All of this took a bit more than 4 hours, most of which of course involved moving and replacing the speakers, and setting up the mic, computer, acoustic panels, etc.
After viewing the impulse response plots corresponding to each of the measurements (on a much larger screen than my laptop provides), as I had suspected the ones taken with the acoustic panels surrounding the microphone were clearly the best, with the ones taken with the panels surrounding the speaker also being significantly better than the ones taken with no panels in place. The 2.5 foot measurements looked a bit better than the 3 foot measurements, which in turn looked a bit better than the 3.5 foot measurements. But Im inclined to go with the 3 foot measurements due to the concern I expressed earlier in the thread about timing artifacts resulting if very close-up measurements are used, given the somewhat wide spacing of the drivers on my speakers.
The next step will be to generate speaker corrections in the software, utilizing those measurements. Ill probably create two sets of corrections, one conservative and one somewhat aggressive, and upload them to separate profiles on the DEQX. Ill then evaluate the resulting sonics with a variety of recordings, before attempting any room corrections. My next significant update is likely to be several days or more from now.
Finally, Ill mention that Nyal (AcousticFrontiers), from whom I purchased the HDP-5, was kind enough to contact me the other day to see how I was doing with it, and graciously offered to review and comment on my DEQX project file. Ill probably take him up on that in the coming days or weeks.
Best regards,
--Al