Re: Cellphones and Audio (was Ghost Click, though I got no idea why)
Adam Atkinson gh...@mistral.co.uk wrote; Jay Ashworth wrote: Now, those codecs *are* specially tuned for spoken word -- if you try to stuff music down them, it's not gonna work very well at all... It was claimed to me many years ago that the 4kHz cutoff used in POTS serves women and children less well than it does adult males. I have never been aware that I have any greater problems understanding women or children on the phone than I do men, but my hearing is not great. I can't hear the difference between G.711 and G.729, for example, but some people can. Googling PCM adult male voice, 4kHz adult male and similar isn't finding me anything. Was I told nonsense? Probably. sort of. grin 'Way back when', at least in the U.S., the 'voice' passband was 300-3000Hz. Later, 300-3300Hz. For perspective, rf you know anything about music, the 'A' below Middle C' is nominally 440Hz. 300Hz is roughly an octave below Middle C, and 3kHz is 2-1/2 octaves above it. That's the -high- end of the range for a piccolo, or coloratura Soprano. Now, absent the overtones that give a note it's 'color', one of those high-pitch sources will sound more than a little bit 'tinny' over a classical 'voice passband' channel. *HOWEVER*, the 'fundamental' frequencies for womens/childrens voices -is- higher than that of adult males. But you're talking less than an octave in 'most' cases. Less than 2 in 'extreme' (a guy with a _deep- bass voice -- basso profundo, and a 'squeaky' female/child) cases. This mean that one does lose one to two additional 'overtones' of the fundamental on women/children, vs. men. This does, in general, *NOT* materially affect the 'intelligibility' of the voice, although it does have a measurable adverse effect on the 'identifiability' of one such higher-pitched voice vis-a-vis a different similarly-pitched voice. You lose more of the 'color' of their voices vs the lower-pitched male voice.
Re: Cellphones and Audio (was Ghost Click, though I got no idea why)
- Original Message - From: Adam Atkinson gh...@mistral.co.uk Jay Ashworth wrote: Now, those codecs *are* specially tuned for spoken word -- if you try to stuff music down them, it's not gonna work very well at all... It was claimed to me many years ago that the 4kHz cutoff used in POTS serves women and children less well than it does adult males. I have never been aware that I have any greater problems understanding women or children on the phone than I do men, but my hearing is not great. I can't hear the difference between G.711 and G.729, for example, but some people can. Googling PCM adult male voice, 4kHz adult male and similar isn't finding me anything. Was I told nonsense? No, you weren't. A 4khz channel is generally good from 3-400hz up to about 3.4khz, and if you look at spectrograms of the various categories of voices you can see the differences, though they're not always as clear cut as you might expect: http://www.dplay.com/tutorial/bands/index.html In general, though, intelligibility comes from the higher frequencies, and 3.4kHz is *usually* high enough. What might be the case is that you'd have more trouble *distinguishing* amongst women, or between women and children, because the tones necessary for that are more located above the cutoff frequency. In short: it depends a lot on what you mean by 'serves well'. :-) Cheers, -- jra -- Jay R. Ashworth Baylink j...@baylink.com Designer The Things I Think RFC 2100 Ashworth Associates http://baylink.pitas.com 2000 Land Rover DII St Petersburg FL USA http://photo.imageinc.us +1 727 647 1274
Re: Cellphones and Audio (was Ghost Click, though I got no idea why)
On Thu, 03 May 2012 11:01:01 -0400, Jay Ashworth said: In general, though, intelligibility comes from the higher frequencies, and 3.4kHz is *usually* high enough. What might be the case is that you'd have more trouble *distinguishing* amongst women, or between women and children, because the tones necessary for that are more located above the cutoff frequency. I have had more than a few surreal conversations on the phone with my daughter - once the 3.4kHz filter gets done, I can't distinguish her voice from her mom's (and yes, I've gotten social-engineered as a result). Life has gotten simpler since she got old enough to have her own cell phone. ;) pgpyVSYGgjivf.pgp Description: PGP signature
Re: Cellphones and Audio (was Ghost Click, though I got no idea why)
Jay Ashworth wrote: Googling PCM adult male voice, 4kHz adult male and similar isn't finding me anything. Was I told nonsense? [snippage] What might be the case is that you'd have more trouble *distinguishing* amongst women, or between women and children, because the tones necessary for that are more located above the cutoff frequency. Thank you for this and the link. Very interesting stuff. I have never tried to check to what extent I / others can distinguish different female / young speakers on the phone. I shall try to pay more attention to this in the future. In short: it depends a lot on what you mean by 'serves well'. :-) Well, just the above seems like enough that you'd think there'd be more (justified) grumbling that thanks to a choice made many many decades ago it's harder to distinguish young or female speakers than it is adult male ones. Maybe there is and I've just not noticed it. Is this one of the things pushing adoption of higher bandwidth audio codecs? (My guess: no.)
Re: Cellphones and Audio (was Ghost Click, though I got no idea why)
- Original Message - From: Adam Atkinson gh...@mistral.co.uk Well, just the above seems like enough that you'd think there'd be more (justified) grumbling that thanks to a choice made many many decades ago it's harder to distinguish young or female speakers than it is adult male ones. Maybe there is and I've just not noticed it. Is this one of the things pushing adoption of higher bandwidth audio codecs? (My guess: no.) Not directly, I don't think, no. I suspect it's merely why not? Cheers, -- jra -- Jay R. Ashworth Baylink j...@baylink.com Designer The Things I Think RFC 2100 Ashworth Associates http://baylink.pitas.com 2000 Land Rover DII St Petersburg FL USA http://photo.imageinc.us +1 727 647 1274
Re: Cellphones and Audio (was Ghost Click, though I got no idea why)
On 5/3/12 10:29 , Jay Ashworth wrote: - Original Message - From: Adam Atkinson gh...@mistral.co.uk Well, just the above seems like enough that you'd think there'd be more (justified) grumbling that thanks to a choice made many many decades ago it's harder to distinguish young or female speakers than it is adult male ones. Maybe there is and I've just not noticed it. Is this one of the things pushing adoption of higher bandwidth audio codecs? (My guess: no.) Not directly, I don't think, no. I suspect it's merely why not? wideband codecs carry music a lot better. the can have considerably more dynamic range than you can expect from an 8 bit pcm mulaw encoding (about 45bB). that helps a lot in the speaker phone situation. if you have the opportunity to compare pstn and mp3 recordings of the same meeting like I do on occasion the difference is considerable. Cheers, -- jra
RE: Cellphones and Audio (was Ghost Click, though I got no idea why)
As one involved in emergency services I don't gave a rats whether you can't tell one voice from another. I do care if someone who is having a fire, accident, cardiac episode or stroke can get through. The cell companies are worrying about your whim and not the safety. Ralph Brandt -Original Message- From: valdis.kletni...@vt.edu [mailto:valdis.kletni...@vt.edu] Sent: Thursday, May 03, 2012 11:33 AM To: NANOG Subject: Re: Cellphones and Audio (was Ghost Click, though I got no idea why) On Thu, 03 May 2012 11:01:01 -0400, Jay Ashworth said: In general, though, intelligibility comes from the higher frequencies, and 3.4kHz is *usually* high enough. What might be the case is that you'd have more trouble *distinguishing* amongst women, or between women and children, because the tones necessary for that are more located above the cutoff frequency. I have had more than a few surreal conversations on the phone with my daughter - once the 3.4kHz filter gets done, I can't distinguish her voice from her mom's (and yes, I've gotten social-engineered as a result). Life has gotten simpler since she got old enough to have her own cell phone. ;)
Re: Cellphones and Audio (was Ghost Click, though I got no idea why)
Jay Ashworth wrote: Now, those codecs *are* specially tuned for spoken word -- if you try to stuff music down them, it's not gonna work very well at all... It was claimed to me many years ago that the 4kHz cutoff used in POTS serves women and children less well than it does adult males. I have never been aware that I have any greater problems understanding women or children on the phone than I do men, but my hearing is not great. I can't hear the difference between G.711 and G.729, for example, but some people can. Googling PCM adult male voice, 4kHz adult male and similar isn't finding me anything. Was I told nonsense?
