Sound issue
in [UK Mac]
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From: J. J. Lodder on 23 Dec 2009 10:34 Adrian Tuddenham <adrian(a)poppyrecords.invalid.invalid> wrote: > J. J. Lodder <nospam(a)de-ster.demon.nl> wrote: > > > Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote: > > > > > Jaimie Vandenbergh <jaimie(a)sometimes.sessile.org> wrote: > > > > > > > gavsko <gcrosswell(a)aol.com> wrote: > > > > > > > > >I run itunes from a G4 quicksilver through an amp to provide music for > > > > >the whole house. All the vocal sound now appears as if it is in the > > > > >background (for CDs aswell). I thought it may be the amp blowing a > > > > >channel but I tested it using a friend's machine and it's fine. Is the > > > > >headphone socket (from where the phonos run) or hardware damaged or > > > > >could it be (hopefully) a software issue? (10.4.11 OSX) > > > > > > > > Is the wiring set up such that you could possibly have one of your > > > > stereo channels crosswired? You get odd audio effects like that if you > > > > miswire one of the speaker cables. > > > > > > It does sound like phase reversal on one channel to me - at least, if > > > it's the case that the only part of the signal that's common to both > > > channels is `vocals' and only the vocals are so affected. > > > > Reversing the phase on both channels surely makes it worse still. > > Seriously though, a phase reversal doesn't afffect the vocals. > > It's the basses, below about 400 Hz, that sufffer, > > The bass will suffer too, but the vocals are often pan-potted mono, so > they cancel when the phase of one channel is reversed. Supposing them to be centred, which is rarely the case. What is usually done is putting most of the soloist on one channel, and the acompaning instruments on the other. Bass below 400 Hz otoh is always centred. (because people may need all the power they can get) (and because vertical amplitude had to be limited, is vinyl days) > The amount of cancellation will depend on the accuracy of channel > matching and the listener's position relative to the two loudspeakers. And on the sound engineers idea of pan. > If part of the system is running in mono, that would knock out the > vocals almost completely. It would, and that is precisely the reason why the singer is rarely in the centre. You might have a point for a background choir though. Stereo is (or should be) designed with the idea in mind that it shouldn't be too bad to reduce it to mono, even with the wrong phase, Jan
From: Jaimie Vandenbergh on 23 Dec 2009 10:34 On Wed, 23 Dec 2009 15:04:52 -0000, "Graham J" <graham(a)invalid> wrote: > >"Rowland McDonnell" <real-address-in-sig(a)flur.bltigibbet.invalid> wrote in >message >news:1jb6jkf.11xh69a1b8w1e5N%real-address-in-sig(a)flur.bltigibbet.invalid... >>T i m <news(a)spaced.me.uk> wrote: >> >>> real-address-in-sig(a)flur.bltigibbet.invalid (Rowland McDonnell) wrote: >>> >>> >300Hz is a `typical highish voice tone' (I hope) >>> > >>> When I was with BT we talked of 'voice' paths being from 300Hz to >>> 3300Hz suggesting 300Hz was a pretty low voice tone (if we are talking >>> about the same things)? >> >> I've no idea what a `voice path' might be - but 3kHz is `overtone' >> territory for the human voice, not a fundamental. At least, not for >> anyone pitching their voice in the usual range. >> >> Hmm. >> >> "In telephony, narrowband is usually considered to cover frequencies >> 300-3400 Hz." >> >> Okay, so I dunno. 400Hz sounds pretty high pitched to me and telephone >> voices do seem to be missing the lower frequency part of the voice >> sounds, so I've thought for as far back as I can recall. Don't have a >> spectrum analyzer handy - if I did, I'd have a look. > >I think the voice frequencies that make for intelligibility exist in the >300Hz to 3kHz range. Below 300 Hz if the loss is 6dB per octave the >attenuation of a typically male voice is not all that significant. I >suspect that below about 100Hz the attenuation is much more than 6dB per >octave, since typical telephony paths traditionally used transformers and >similarly constructed transducers. Somewhat informative thing about this at http://www.cisco.com/en/US/prod/collateral/voicesw/ps6788/phones/ps379/ps8537/prod_white_paper0900aecd806fa57a.html >For music of course very few people appreciate anything over about 15kHz >(and those that do complain bitterly about TV line whistle). I know I do. Can't wait to toss this nasty SD bubblescreen, although fortunately it's only audible when the speakers are muted. I informally tested my auditory top range yesterday, I can hear 17kHz but not 18kHz, which matches the hospital test when I was 23 (now 36). Frankly I'd rather my ears topped out at around 16kHz since only nasty electronics make the higher pitches and it's only a negative utility to me. And yes, this means I can hear those "mosquito" annoy-a-teen things. I used http://www.nch.com.au/tonegen/index.html for anyone wanting to play along. Cheers - Jaimie -- Thank you for your input. Now, if you have something substantive to bring to the discussion, kindly do. Otherwise, isn't there an eternal flamefest that would peter out if you won't keep feeding it? -- Cosmin Corbea, r.a.b
From: J. J. Lodder on 23 Dec 2009 11:06 Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote: > T i m <news(a)spaced.me.uk> wrote: > > > real-address-in-sig(a)flur.bltigibbet.invalid (Rowland McDonnell) wrote: > > > > >300Hz is a `typical highish voice tone' (I hope) > > > > > When I was with BT we talked of 'voice' paths being from 300Hz to > > 3300Hz suggesting 300Hz was a pretty low voice tone (if we are talking > > about the same things)? > > I've no idea what a `voice path' might be - but 3kHz is `overtone' > territory for the human voice, not a fundamental. At least, not for > anyone pitching their voice in the usual range. > > Hmm. > > "In telephony, narrowband is usually considered to cover frequencies > 300–3400 Hz." > > Okay, so I dunno. 400Hz sounds pretty high pitched to me and telephone > voices do seem to be missing the lower frequency part of the voice > sounds, so I've thought for as far back as I can recall. Don't have a > spectrum analyzer handy - if I did, I'd have a look. For the stereo signal 400 Hz is the roll-over point. below that the S-component drops with the usual 6 dB/octave. Bass singers are therefore hardly affected, Jan
From: Rowland McDonnell on 23 Dec 2009 04:32 Adrian Tuddenham <adrian(a)poppyrecords.invalid.invalid> wrote: > J. J. Lodder <nospam(a)de-ster.demon.nl> wrote: > > > Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote: > > > > > Jaimie Vandenbergh <jaimie(a)sometimes.sessile.org> wrote: > > > > > > > gavsko <gcrosswell(a)aol.com> wrote: > > > > > > > > >I run itunes from a G4 quicksilver through an amp to provide music for > > > > >the whole house. All the vocal sound now appears as if it is in the > > > > >background (for CDs aswell). I thought it may be the amp blowing a > > > > >channel but I tested it using a friend's machine and it's fine. Is the > > > > >headphone socket (from where the phonos run) or hardware damaged or > > > > >could it be (hopefully) a software issue? (10.4.11 OSX) > > > > > > > > Is the wiring set up such that you could possibly have one of your > > > > stereo channels crosswired? You get odd audio effects like that if you > > > > miswire one of the speaker cables. > > > > > > It does sound like phase reversal on one channel to me - at least, if > > > it's the case that the only part of the signal that's common to both > > > channels is `vocals' and only the vocals are so affected. > > > > Reversing the phase on both channels surely makes it worse still. > > Seriously though, a phase reversal doesn't afffect the vocals. > > It's the basses, below about 400 Hz, that sufffer, What sort of frequency range do you think the fundamental tones of the human voice occupy? 400Hz isn't a low voice note if you ask me - being (more or less) A above middle C. > The bass will suffer too, but the vocals are often pan-potted mono, so > they cancel when the phase of one channel is reversed. That's what I thought - although wandering around the room will probably result in the cancellation failing, sortathing. I think... Hmm. Well, 300Hz and 300m/s -> wavelength 1m. So maybe - can't see voices going down to 30Hz, much (wavelength 10m). (300Hz is a `typical highish voice tone' (I hope); 300m/s is approx the speed of sound at sea level etc; 1m is the wavelength of 300Hz sound in a 300m/s speed of sound medium.) > The amount of cancellation will depend on the accuracy of channel > matching and the listener's position relative to the two loudspeakers. First pass approximation, yeah. But what about all those room effects, eh? ... I should try some experiments here, see what I can get. [snip] Rowland. -- Remove the animal for email address: rowland.mcdonnell(a)dog.physics.org Sorry - the spam got to me http://www.mag-uk.org http://www.bmf.co.uk UK biker? Join MAG and the BMF and stop the Eurocrats banning biking
From: Rowland McDonnell on 23 Dec 2009 04:32
Adrian Tuddenham <adrian(a)poppyrecords.invalid.invalid> wrote: > gavsko <gcrosswell(a)aol.com> wrote: > > > I run itunes from a G4 quicksilver through an amp to provide music for > > the whole house. All the vocal sound now appears as if it is in the > > background (for CDs aswell). I thought it may be the amp blowing a > > channel but I tested it using a friend's machine and it's fine. Is the > > headphone socket (from where the phonos run) or hardware damaged or > > could it be (hopefully) a software issue? (10.4.11 OSX) > > A further thought: > > If a 3.5mm jack plug isn't fitting right into the socket, it can pick up > incorrect channel and earth connections; that would give the effect you > describe if the vocals were recorded predominantly on the missing > channel. > > Have a look and see if the plastic body of the plug is fouling the > computer casing and preventing the plug from going right in. I've noticed that my made-at-homes leads with 3.5mm jack plugs often don't go in properly to some sockets, but that factory-made leads with 3.5mm jack plugs so far always have. Nothing wrong with my soldering; it's the blasted plug and/or sockets having dimensions that are slightly off spec - the pin of the plug seems to be too short, in short. Sometimes I wonder if it's because they make 'em to Imperial dimensions some places and metric in others (Yanks refer to 3.5mm jack plugs as 1/8" jacks, apparently, which is wrong 'cos they're metric and even crusty old technicians still working with thermionic valves and steam engines called 'em that in the early 1970s. Yes, I remember and no I can't remember the 1960s, thus proving I was there.) Rowland. -- Remove the animal for email address: rowland.mcdonnell(a)dog.physics.org Sorry - the spam got to me http://www.mag-uk.org http://www.bmf.co.uk UK biker? Join MAG and the BMF and stop the Eurocrats banning biking |