High Quality Sat Radio

[Negotiableterms]

Polk introduced its XM unit a long while back. I grabbed one, and plugged it in...yuck. I plugged the digital ouptut into a 24/192 DAC (Grace m902)...better, but nothing to write home about. This weekend, I'm gonna plug it into a Mc MDA-1000.

Any advance speculation as to whether a 24/768 DAC can save it?

[theodoric]

Silk purse, sow's ear, all that.

[tentoze]

Hope it works out better for you, but you know what they say about polishing a turd.

[uofmtiger]

You are dealing with a compressed signal and lost information is lost no matter what you do. XM is great for finding unfamiliar music and selection, but sound quality is not the best.

It is great for noncritical listening or listening to in compromised areas like a car or office. I have XM on Directv and rarely listen to it, but I love it at work, outside, and in the car.

[JimmyNeutron]

My Meedio front end on my music server is able to recieve XM digital broadcasts ( a freind turned me on to his account and that's how I can recieve it). Personally, I didn't expect too much. Just like uofmtiger said, it's a compressed format and will never be a CD quality format". With that expectation in mind I find that I really enjoy it. I have it on a good part of the day, as I do internet streaming radio staions and I like it alot. The sound is comparable to a 128K mp3, maybe better at times. Seeing that my only other choice is FM with it's shitty commercials every 15 minutes and the repeats of the "Song of the moment" every other 10 minutes, I have absolutely no problem with the lack of "CD quality" sound among digital radio. It gets my vote: I like it. :thmbsp:

[Negotiableterms]

I have XM on Directv and rarely listen to it, but I love it at work, outside, and in the car.

Is the XM signal on Directv the same compression system as on XM itself?

[uofmtiger]

Is the XM signal on Directv the same compression system as on XM itself? I have no reliable source for this, but I have read that Directv actually uses a different and more aggressive compression technique. According to the source (from an XM forum), Directv is fed an uncompressed stream and they compress it themselves using mpeg2. XM typically uses AAC+.

I will do a comparison at some point when I get a chance. I also have XM piped into the main room via a computer connection. To be honest, I rarely listen to XM at home. I usually have it on all day at work, so when I get home I listen to my own stuff. However, AVSforum has tons of complaints related to the Directv stream. I have not even bothered with critically listening to the Directv stream because I am already aware of the compression issues.

[JimmyNeutron]

Well, for the past couple of days I've been doing some semi-critical comparisons of XM radio over the internet, CD, and FM radio. I don't have an XM *satellite* radio, I get mine over the internet through XMradio.com. I'm a subscriber. I recieve their stations on my music server and on my regular computer both connected to my McIntosh C-39 pre and my MC-7270 amp. The CD player is a Denon DVD-2900, which has gotten rave reviews for it's superd CD section. The FM tuner is a Denon TU-550 digital tuner. To start and to summerize: FM don't have SH*T!!! It's plaqued with interference, is antenna placement critical, content is limited and what is there just plain sucks, and is littered with the barrage of commercials which in of itself is enough to turn people onto XM radio. Ofcourse the quality of the antenna will play a big role in the quality of the fidelity from the FM radio, but after the investment of the purchase and installation of an arial antenna mounted on a pole on the tip of your roof you have to wonder if it was wise not to invest that money in the simplicity that is satellite radio. XM radio, at least over the internet, sounds wonderful. Earlier I said it sounded like a 128kps mp3, but I regress. It is indeed CD quality - of a lower version. I would rate it as a 260kps minimum. It certainly beats the crap out of FM - no comparision. The variety is also incredible - many channels to choose from. The sound quality is consistant on broadband - no drop outs or buffering. Just consistant, high quality music and a huge variety. CD is, of course, CD - a high quality format. XM is not CD because it's compressed. But I'll bet if you just walked into a room with XM playing a good tune you'd be hard pressed to know it was not a CD.

I've read many articles bashing the sound and quality of XM radio - but I just cannot see it. It has consistently delivered in the important areas - 1: variety, 2: sound quality, and 3: consistency. When I hear people say XM sounds like crap I ask myself "Is it XM that sounds like crap or their stereo?" I like it.

Jimmy

[Negotiableterms]

Well... the results are that XM sounds better with a 24/768 DAC... but still not very good. It's nothing like a CD played through the same DAC. The highs are still missing, and the bass is muddy. Oh well; sorry to disagree, Jimmy.

[uofmtiger]

XM has traditionally been reticent to reveal technical information about its bit-rate and its codec specs, presenting these as proprietary issues in a competitive environment. However, many observers (ourselves included) suspect that the true figures are just plain embarrassing. Divide the available bandwidth by the number of channels and each XM channel would seem to be providing data at a mere 64kbps, a bit rate well below the lossy 128kbps that makes the average MP3 recording sound uninvolving. Stereophile Magazine (http://www.stereophile.com/news/011606xmmg/index.html)

The article also mentions that XM is adding:
XM HD Surround, "six discrete channels of digital full-fidelity audio,"

However, they are worried that this will further cut back the bandwidth to each channel. Personally, I think the talk channels are compressed more than the music channels, but the best channels probably fall between 64Kbps and 128kbps depending on the channel you choose.

Keep in mind I am not an XM basher. I have had the service for several years and I love it. However, I feel variety and the lack of commercials (although they do have some XM promos) on the music channels are the most important issue to me and a lot of other people. Sound quality will not be a reason I recommend XM, unless they get more bandwidth or they drastically improve compression technology.

[JimmyNeutron]

Oh well; sorry to disagree, Jimmy.


Not a problem, that's what discussions are for. Still, the XM I listen to still sounds very impressive. Heck, I'm listening to it as I type. Could it be that the XM stations delivered over the internet have less compression and higher frequency range than XM delivered through satellite?

[uofmtiger]

Could it be that the XM stations delivered over the internet have less compression and higher frequency range than XM delivered through satellite? I doubt it. The streams are delivered via a 64kbps stream.

[Art K.]

I use a Yamaha RX-V657 receiver as an AM/FM/XM tuner only and love the XM. The sound quality is not all that and is quite variable. I listen to channels 70 and 110 the most and the sound quality of those 2 channels is very good (not excellent). So to is the playlist and programming. My XM radio has become one of my most listened to sources.

[shstrang]

I think this is strange but it seems to me the XM channels on DirecTv sound better than with an XM receiver. Both sirus and XM both have a lot of artifacts but XM on DirecTv doesn't (or at least that I can hear).

[shstrang]

Not that there's any way in hell this would happen but I really wish XM would try to improve their stereo channels before offering surroundsound. All the surround will do is give you crap sound in the round.:D