DAT-heads Digest #532, Volume #7 Mon, 4 Jul 05 15:50:02 EDT Contents: XM radio - how does it compare to FM? ("Kevin Kachel") Re: XM radio - how does it compare to FM? (Gary Gilliland) FT: U2 - Vienna 2 july 2005 (dpa4061 + M1 source) (Luigi Bagatella) ---------------------------------------------------------------------------- From: "Kevin Kachel" Subject: XM radio - how does it compare to FM? Date: Sun, 03 Jul 2005 21:27:00 -0400 "There are already various tapes of XM's Live 8 broadcasts circulating on the torrent sites. I'm curious to know the opinion of US tapers about the quality of XM - would a pure digital capture (if that's possible) of XM be considered a better or worse source than a very good FM recording?" There is nothing good about the quality of XM "digital" radio. It is popular because of its convenience and diversity. If you were to record XM digitally, you would not have what was present on the original cd because XM uses compression before it's transmitted. Yes it is digital, but it is not lossless. kind of analogous to mp3. FM is also lossy, but if you are recording from a high quality station that uses little compression and actually cares about quality, an FM recording should be better than XM. Kevin ------------------------------ From: Gary Gilliland Subject: Re: XM radio - how does it compare to FM? Date: Mon, 4 Jul 2005 04:25:51 +0000 (GMT) Dave wrote: > I'm curious to know the opinion of US tapers about the quality of XM - > would a pure digital capture (if that's possible) of XM be considered a > better or worse source than a very good FM recording? It is pretty much impossible to compare XM (in the abstract) with anything else as it utilizes proprietary variable bit rates which are subject to channel-to-channel change without notice (except encoded to the receivers) and notice without change (as found on some blogs). Quality seems to vary not only from channel-to-channel but also from hour-to-hour and, perhaps, even from selection-to-selection. Following the lead of the closed-source vendor from Redmond WA, XM has made no announcement AFAIK about bit rate(s), frequency response(s), dynamic range(s), harmonic distortion(s), IM distortion(s), channel separation(s), S/N ratio(s) or any other parameter one would normally expect to be able to compare from source to source. XM receivers seem all to utilize the same (XM-proprietary) chipset, at least as far as converting the XM to PCM (or something very like PCM). The Polk XM receiver has S/P-DIF outputs (both RCA/Cinch & TOSLINK), so a "pure digital capture" (of sorts) is possible, but all the smoke and mirrors associated with XM's proprietary codec have already worked their magic (mudgic?) on the original audio, albeit in the digital domain. My listening tests have been quite limited, but I have yet to hear anything I identify as "FM quality," by which I mean what one would expect to hear on a monitor-grade receiver with a good signal from an FCC- licensed FM station passing its proof-of-performance measurements, playing listening material directly from a CD to the transmitter. (This may only happen at about 3:00 to 4:00 AM of a Sunday morning, for about five minutes, once a year.) It has been said that XM Channel 27 "Cinemagic" has a high-quality program, but it seems no better to me than was common in motion picture theatres after Dolby but before THX. XM Channel 24 "Sunny" sounds like elevator music (content) and about the quality that we used to broadcast on a 67kHz subcarrier from huge 1/4" tape reels running at 3-3/4 ips. What is done today in broadcast (open air, cable, and direct-satellite) is not pretty. What is done in sound reinforcement is no prettier. So my bottom line, FWIW, is: "You pays your money and you takes your chances." An A/B, or preferably an A/B/C comparison (with C being a good live recording bypassing all the sound reinforcement and post-production gimmicks), would be very interesting, but likely of limited predictive value for other events. Hope this helps. Gary ------------------------------ From: Luigi Bagatella Subject: FT: U2 - Vienna 2 july 2005 (dpa4061 + M1 source) Reply-To: luigi.bagatella@tin.it Date: Mon, 04 Jul 2005 16:39:49 +0200 I taped U2 last saturday in Vienna, Austria: Dpa4061s + Mps6030 + M1 (48khz, 135') Excellent sound, right in front of the main left stack. Looking for any other U2 show, except Popmart and Elevation tour. Now I can do dat clones. Tapers only, please. ciao Luigi ------------------------------ ** FOR YOUR REFERENCE ** To unsubscribe from this digest, please send email to dat-heads-unsubscribe@datheads.phish.net If your email address has changed, you may (optionally) send the message to dat-heads-unsubscribe-oldaddress=olddomain@datheads.phish.net and the old address will be removed. Problems or questions about a subscription should be addressed via these avenues and then if needed to dat-heads-owner@datheads.phish.net or postmaster@datheads.phish.net never the list itself You can submit a message for inclusion in the next digest via this address: Internet: dat-heads@datheads.phish.net Archives of DAT-Heads digests and related files are available on the DAT-Heads home page: http://www.solorb.com/dat-heads/ End of DAT-Heads Digest ******************************