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#41
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In article qPh2f.3087$jw6.857@lakeread02,
"ScottW" wrote: "MINe 109" wrote in message ... Thanks. When that center channel happens, I'll check out the Delos test disc. Isn't the levels signal out of most receivers pink noise? Both my receiver and DVD player (as it has builtin decoders) has level test signals that sounds like pink noise to me. I don't have a receiver yet. I think my dvd player mmight have some kind of test tone. Stephen |
#42
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"MINe 109" wrote in message ... In article qPh2f.3087$jw6.857@lakeread02, "ScottW" wrote: "MINe 109" wrote in message ... Thanks. When that center channel happens, I'll check out the Delos test disc. Isn't the levels signal out of most receivers pink noise? Both my receiver and DVD player (as it has builtin decoders) has level test signals that sounds like pink noise to me. I don't have a receiver yet. I think my dvd player mmight have some kind of test tone. Pink noise sounds like a radio not tuned to a station with the muting off. No tone quality to it. ScottW |
#43
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In article m%m2f.3105$jw6.768@lakeread02,
"ScottW" wrote: "MINe 109" wrote in message ... In article qPh2f.3087$jw6.857@lakeread02, "ScottW" wrote: "MINe 109" wrote in message ... Thanks. When that center channel happens, I'll check out the Delos test disc. Isn't the levels signal out of most receivers pink noise? Both my receiver and DVD player (as it has builtin decoders) has level test signals that sounds like pink noise to me. I don't have a receiver yet. I think my dvd player mmight have some kind of test tone. Pink noise sounds like a radio not tuned to a station with the muting off. No tone quality to it. Yes, like on my Stereophile test cd. Stephen |
#44
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ScottW wrote:
"MINe 109" wrote in message ... In article , Howard Ferstler wrote: Me: My next thought involves an already inexpensive Polk center available even cheaper at Fry's. I think I have a pink noise source on a Stereophile test cd. The Delos "Surround Spectacular" test disc (I believe it is still available from the Delos Records web site) has Dolby Surround (matrixed) encoded pink-noise test signals that include left, center (left plus right), right, and surround (left minus right) signals that make it pretty easy to compare spectral balance in all four Dolby Surround channels. The Ovation Software "Avia" test DVD has similar signals in Dolby Digital form for the standard five channels. (They also have a web site that takes orders.) The version put together for Sound & Vision magazine even has an additional test signal for the center-back channel in 6.1 systems. All three also have test signals to help set up subwoofer levels and crossover phase dovetails. The Delos disc even has signals to check out the ability of a Dolby Surround (matrix) decoder and three speakers up front to deliver half-left and half-right imaging with three front channels and a derived (left plus right) center feed. Thanks. When that center channel happens, I'll check out the Delos test disc. Isn't the levels signal out of most receivers pink noise? Both my receiver and DVD player (as it has builtin decoders) has level test signals that sounds like pink noise to me. ScottW Sometimes pink, but also sometimes what appears to be simple white noise or narrow-bandwidth random noise. Any of it should work OK, but regular pink noise, since it includes a balanced amount of bass and treble (equal energy per octave), works better at checking both level matching and spectral balance, especially the latter. Howard Ferstler |
#45
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ScottW wrote:
"MINe 109" wrote in message ... In article qPh2f.3087$jw6.857@lakeread02, "ScottW" wrote: "MINe 109" wrote in message ... Thanks. When that center channel happens, I'll check out the Delos test disc. Isn't the levels signal out of most receivers pink noise? Both my receiver and DVD player (as it has builtin decoders) has level test signals that sounds like pink noise to me. I don't have a receiver yet. I think my dvd player mmight have some kind of test tone. Pink noise sounds like a radio not tuned to a station with the muting off. No tone quality to it. ScottW Because pink noise generates an energy content that is inversely proportional to frequency, the rate of change as the frequency climbs is minus 3 dB per octave - resulting in equal energy per octave. White noise (what you may hear between stations or with some built in receiver signal generators) is constant energy per unit of frequency, which has constant energy per octave. As a result, white noise seems much more treble heavy than pink noise. Either can be used, by ear or meter, to set up balances between speakers in a surround-sound rig, but the advantage of pink noise is that it also allows one to check for spectral balance similarities - by ear. The reason white noise is favored by manufacturers who use it with their receivers is that speakers that are different in terms of their spectral balance abilities (typical when using center speakers that are significantly at variance from the left and right main speakers) will be easier to match by ear. Mismatched speakers can at least be properly level matched. The advantage of pink noise is that it allows the user to see just how much alike his speakers sound in terms of their frequency response smoothness and bass, mid, and treble balance. Howard Ferstler |
#46
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"MINe 109" wrote in message
I don't have a receiver yet. I think my dvd player mmight have some kind of test tone. Stephen, you're so obviously not a mainstream kind of guy! |
#47
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"ScottW" wrote in message
news:m%m2f.3105$jw6.768@lakeread02 "MINe 109" wrote in message ... In article qPh2f.3087$jw6.857@lakeread02, "ScottW" wrote: "MINe 109" wrote in message ... Thanks. When that center channel happens, I'll check out the Delos test disc. Isn't the levels signal out of most receivers pink noise? Yes. Both my receiver and DVD player (as it has builtin decoders) has level test signals that sounds like pink noise to me. Very likely. Pink noise sounds like a radio not tuned to a station with the muting off. Close. The basic process that creates FM interstation noise probably generates pink noise, but FM recievers have demphasis circuits that roll response off based on 50 uSec (Europe) or 75 uSec (US). IOW, above about 2 KHz FM interstation noise gets softer-sounding. No tone quality to it. Well random noise has either no tones or every tone, depending on how you look at it. Scientifically, every tone would be closer to the truth. If you narrow-band filter noise at any frequency in its range, you will recover a tone that was a true and genuine part of the noise signal. So, its more correct to say that a noise signal contains every tone in its range. White noise sounds something like high pressure air escaping from a nozzle, and is pretty nasty to listen to. Pink noise sounds less grevious, but is IME hardly fun to listen to. Its more like the sound that waves make when they crash on the shore. BTW I just spent a week hiking the south shore of Lake Superior, so I heard this sound up front and personal day and night for a week. There was a gale-force storm one night, and that was pretty wild. Interestingly enough, in the past 20 years equipment testing has moved away from the use of noise as an audio test signal. Not to say that people don't still use it, or that using it is invalid. Noise is cheap and easy to make and it can be helpful because of its lack of character. If you play noise though an audio system and hear a distinct character, then that character is probably due to a false coloration of the system. If the audio system is a guitar amp, then character and coloration can be a good thing. If the audio system is a home stereo system, then a false sonic character can become a veil that stands between the listener and the fine tonality of the music. Anybody who tests equipment with a true random noise signal is sort of condemning themselves to an old-fashioned, out-dated kind of test. But it can be better than nothing, by far. |
#48
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"Arny Krueger" wrote in message ... "MINe 109" wrote in message I don't have a receiver yet. I think my dvd player mmight have some kind of test tone. Stephen, you're so obviously not a mainstream kind of guy! We mainstream guys listen to test tones all the time. |
#49
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In article ,
"Arny Krueger" wrote: "MINe 109" wrote in message I don't have a receiver yet. I think my dvd player mmight have some kind of test tone. Stephen, you're so obviously not a mainstream kind of guy! Nope. I'm just curious about what's on the surround channels of my music dvds and hybrid sacds. Does anyone have opinions about the Polk R30 and center channel currently very cheap at Fry's? Stephen |
#50
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Arny Krueger wrote:
Anybody who tests equipment with a true random noise signal is sort of condemning themselves to an old-fashioned, out-dated kind of test. But it can be better than nothing, by far. It has its uses, and is but one of several tests that can be used to evaluate gear, particularly speakers. (It also comes in handy when evaluating surround processors, needless to say.) One thing it can do is allow for comparison testing by ear, again with speakers. That is, one can set up a pair of speakers close together, feed them mono pink noise, and then use the balance control to AB them. Doing this by ear will quickly do three things: 1. It will show that even very good speakers, displaced slightly in space, will have spectral balance differences at the listening position that may be surprising. Indeed, even the most subtle differences between speaker performance (between supposedly identical speakers) will be easily audible with a pink noise test signal. Switch to musical source material and they may sound identical, but pink noise will highlight those subtle differences emphatically. Hence, pink noise is the equivalent of a good test pattern with video. 2. If one of two speakers is defective (problematic or inoperable driver) doing a pink-noise AB comparison will highlight the problem immediately. It is a good test tool for someone who does not have test gear and who wants to know quickly if one of their speakers has a problem. 3. If power response is what matters most to an individual a pink noise source, along with a good RTA, will do a fine job of evaluating that aspect of speaker performance, at least if the testing/listening room is decent and one has an RTA with a continuous averaging feature. That allows one to move the microphone slowly to get an average over a given amount of space. Yes, I know these days the emphasis (even with supposedly knowledgeable enthusiasts and reviewers) is on the direct-field, first-arrival signal getting to the listener. (Thereby locking them into a sweet-spot listening position for satisfactory performance.) There is a certain irony here, because decades ago reviewers already felt this way, and then along came guys like Villchur and Allison, and a few others, and the concept of power response gained a lot of support. This is perhaps why the old Acoustic Research outfit managed to do so well for over a decade. Unfortunately, most systems have problems delivering the power-response goods, so many manufacturers went back to the direct-field philosophy in order to rationalize the limitations of their speakers. Today, many reviewers have embraced the old view of the importance of the first-arrival, direct-field signal, even though one does not need to think much about it to realize that power response eclipses the impact of the direct field in normal rooms even with fairly conventional speakers. I continue to believe that it is the total power response that will matter most when it comes to the ability of a speaker to simulate live music with good, "purist" recordings. To get really good power response and spectral balance at the listening position in most home-listening rooms one needs a speaker with the widest broadband radiation pattern possible. Actually, my last sentence introduces us to another very important aspect of loudspeaker performance. Mark Davis showed a couple of decades back that the wide-angle, full-bandwidth radiation pattern of a system is also critical, and together those two (radiation pattern and power response) are way, way, way more important than the first-arrival, direct-field signal dealt with by various gating measuring devices. And pink noise, working with a good RTA, is a good way to evaluate the power response. And one can also do a good job of measuring the radiation pattern with an RTA and pink noise, provided the job is done anechoically. Outdoors does just fine. So pink noise has its uses, and those uses are important. Howard Ferstler |
#51
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MINe 109 wrote:
In article , "Arny Krueger" wrote: "MINe 109" wrote in message I don't have a receiver yet. I think my dvd player mmight have some kind of test tone. Stephen, you're so obviously not a mainstream kind of guy! Nope. I'm just curious about what's on the surround channels of my music dvds and hybrid sacds. It varies. Some will have not much more than large-space hall ambiance, and those are usually classical releases. This ambiance can have been specifically recorded, or the engineer may have used a synthesizing device with more conventional, two-channel master tapes to fabricate surround ambiance for the surround channels. This is common with reissues of older recordings. Interestingly, with a good home-based DSP receiver an individual may be able to do nearly as good a job with those older two-channel recordings as the engineer does when pulling 5.1 sound out of two-channels and making an SACD or DVD-A release. Other recordings (these are usually pop items) may put both ambiance and individual instruments into the surround channels. I have heard some that even had a piano and/or drum set in the surround channels. Vocalists, too. Some will even create a "phantom" back-center channel and if one has a 6.1 processor it may be possible to switch on the center-back speakers and get a more discrete center-back effect. However, normally this can only be done with the Dolby Digital or DTS alternate tracks on DVD-A releases, because the receiver simply will not offer a center-back playback option with 5.1 SACD or DVD-A. Interestingly, many of those pop (and classical) releases make little use of the center channel. Some ignore it completely. There are probably three reasons for this: 1. The engineer simply does not like the tight focus of a discrete center feed and prefers the more spacious and phasy effect delivered by a phantom center. 2. The engineer may simply not know how to properly record a center image for playback on a discrete center channel. It can be tricky to get the center to have the proper hall ambiance compared to the left and right channels. The soloist may sound like they were recorded in a different space from the ensemble. Done right, however, and a discrete center soloist can improve soundstaging over a wider listening area than what we get with a phantom effect. 3. Some knowledgeable engineers realize that the typical center-channel speaker is horizontally mounted, high up on top of a TV set and is not all that good to begin with. Placement and quality problems will make the center feed sound not all that good, so the engineer simply leaves out a discrete center feed and goes with the phantom image. Howard Ferstler |
#52
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Yamaha Processor (was - Ferstler Shows Up Briefly)
"Arny Krueger" wrote in message ... "ScottW" wrote in message news:m%m2f.3105$jw6.768@lakeread02 "MINe 109" wrote in message ... In article qPh2f.3087$jw6.857@lakeread02, "ScottW" wrote: "MINe 109" wrote in message ... Anybody who tests equipment with a true random noise signal is sort of condemning themselves to an old-fashioned, out-dated kind of test. But it can be better than nothing, by far. What works better? |
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