Sound issue
in [UK Mac]
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From: Adrian Tuddenham on 22 Dec 2009 05:25 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) Try reversing the speaker connections to one speaker only. If the sound improves, someone has tripped over the speaker wiring and put it back wrongly without telling you. -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk
From: Adrian Tuddenham on 22 Dec 2009 05:53 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. The amount of cancellation will depend on the accuracy of channel matching and the listener's position relative to the two loudspeakers. If part of the system is running in mono, that would knock out the vocals almost completely. -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk
From: gavsko on 22 Dec 2009 07:00 Thanks for all your help. I'll go through all suggestions and see what they bring up. What I can say is that the jack works fine in a borrowed computer running through the same amp and speakers and the sound is perfect which I suppose narrows it down to a socket or software problem. I'll post what happens as and when (christmas and all).
From: Steve Firth on 22 Dec 2009 09:42 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) It sounds as if the common connection (earth) has broken so what you are getting is the out of phase differential between right and left channels. Have you tried it with a different lead?
From: Graham J on 23 Dec 2009 10:04
"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. For music of course very few people appreciate anything over about 15kHz (and those that do complain bitterly about TV line whistle). -- Graham J |