Skip to main content ↑ ↓

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: Sirius Radio PAC v4 Audio Codec? (Read 6136 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Sirius Radio PAC v4 Audio Codec?

I spied a press release at Stereophile.com which claims that the new Sirius satellite radio broadcast in North America uses audio compression called PAC v4 by iBiquity Digital, which they claim is the "best" (whatever that means).  Anyway - is anybody familiar with this codec and what is your experience / opinion?

http://www.stereophile.com/shownews.cgi?1385
Was that a 1 or a 0?

Sirius Radio PAC v4 Audio Codec?

Reply #1 –
I am not farmilliar with the codec itself, but I have heard Sirius radio and it does not sound very well.  Maybe it would sound better if I heard it while driving down the street, but when I heard it in a buddy's car, I wasn't very impressed.  I did notice that certain channels had slightly better, but I'm sure that is because different stations on the Sirius have different birates because of the rather low bandwith all around and the amount of stations.  I imagine that the talk stations have a much lower bitrate than say, a classical music station.

Sirius Radio PAC v4 Audio Codec?

Reply #2 –
PAC is a codec developed by Lucent (AT&T in the beginning)

It uses 1024/128 point MDCT, 49/14 scalefactor bands and 128-step non-uniform quantization.  It also uses M/S stereo for coding of stereo signals.

These features of PAC were copied to AAC design in 1994.

New versions of PAC algorithm use some new coding tools.

Unfortunately - even the best implementation of PAC is not as good as they want to show.  In AES listening tests PAC was significantly worse than AAC at the same bit rate, but it was better than AC-3 at bit rates less than 160 kbps.

PAC was getting a heavy level of marketing from Lucent - they claim that PAC is 'best in the world' codec - they even cite one listening test where PAC was better than MP3 and AAC.  Unfortunately, the AAC implementation they used was also from Lucent and it wasn't near to the best AAC quality.  In the 'real' listening test  versus AAC implementation from AT&T / Dolby / FhG    PAC was completely inferior.

Sirius Radio PAC v4 Audio Codec?

Reply #3 –
Whatever they use it sounds like crap because the maximum bitrate is 64 Kbps.  I dont care what fancy CODEC you use it's going to sound bad @ 64K.  I was so disapointed with both Sirus and XM.  Ibiquity digital radio will probably sound decent however, at an initial 128K, up to 192 or something like that.

Bryn

Sirius Radio PAC v4 Audio Codec?

Reply #4 –
I read an 'on the road review' for sirius and xm and they said both had 'swishing sounds' audible while parked or driving. They felt sirius was the inferior of the two. Sorry- no link- but it's this July/August Sound and Vision- I looked, just can't find the link for this particular article- page 76. Aparently- limiting bandwith to provide so many stations makes for poor quality- they could learn a lot from this site it seems. Sirius has fewer satellites- poorer quality sound. Oh well- I had been looking forward to it.

Sirius Radio PAC v4 Audio Codec?

Reply #5 –
Yes I thought that review was pretty good.  They did say that at the time Sirius was not even fully operational yet, and the sound as they tested it would be improved upon, and I would imagine this to be correct if Sirius wants to keep up with XM.  Sirius also has one big advantage over XM, they can reconfigure the data allocation for a particular channel on the fly where XM operates each channel at a fixed bitrate.  This gives Sirius some of the same advantages that VBR MP3's have.  The article didn't say that Sirius has less satellites than XM, in fact they have one more because they operate at an inclined orbit.

I had been looking forward to it to, I have always wanted something like music choice or DMX in my car, but for now the sound is just too horrid (XM) on any channel to listen to for more than 5 minutes without getting a headache.  mabey someday they will evolve into something better if it is successful.

Sirius Radio PAC v4 Audio Codec?

Reply #6 –
or maybe it would be successful if they didn't sacrifice so much quality...

Sirius Radio PAC v4 Audio Codec?

Reply #7 –
I don't think that will have as much of an effect as other issues, such as auto manufacturers putting OEM satellite radios in new cars.  It seems that most people think that the sound of XM is better than FM and way better than AM, wich it isn't (not by a long shot).  People mosly confuse the better sound with an extended frequency range and lack of noise.  I on the otherhand would rather have a good limited frequency range than a artifact laden full range, for instance I will take AM talk any day over the same talk program on XM @ 32K. 

The main areas where XM has an advantage is the selection, especially for people who drive alot or live in rural areas.  They have a limited bandwith of 4 MHZ, and if they cut the number of channels in half (wich they should do) then the vast majority of people will see this as less of a value, and more apt to subscribe to Sirius than ask why XM has half as many channels.

Sirius Radio PAC v4 Audio Codec?

Reply #8 –
You'd never know about poor sound quality from the likes of TechTV's review of XM. . . they practically cream themselves over the format. (Makes me wonder if XM didn't slip some money under the rug in exchange for a good review  ). They used terms in the order of "awesome" and "fantastic" when describing the sound quality of streams, and stated that the "lows and highs were better defined than those on FM radio". Users who posted comments about the article also echoed this sentiment, and one guy even said it "sounds better than CD".  I would love a satelite radio since I have a four hour-drive though the open prairies of Illinois to get from school to home, and there is nothing but country-western (AHHH!!) stations until about 50 miles from Chicago (where I'm from).  However, I am officially discouraged given what I have heard. Not that FM sounds all that great anyway. . .the local classic rock station in town is now broadcasting 128kbps Xing encodes instead of CD's 

64kbps?? I'd rather listen to the cows mooing outside my windows than artifact-laden mockeries of my favorite music. Looks like my Rush CD's will continue to serve me well 

My God, where have all the golden ears gone?

Sirius Radio PAC v4 Audio Codec?

Reply #9 –
WTF 128 Xings???

That damn radio station is crazy... but anyway FM wont sound any better than that, wll just a little

Sirius Radio PAC v4 Audio Codec?

Reply #10 –
Quote
Originally posted by Phobos
WTF 128 Xings???

That damn radio station is crazy... but anyway FM wont sound any better than that, wll just a little


Gotta hand it to them, though--at least its not WMA!!! Nothing says you hate music more than converting it to a format that leaves it sounding like it came out of R2D2

Sirius Radio PAC v4 Audio Codec?

Reply #11 –
With all the glorious reviews I almost thought that I had a bad unit, that is until I found out that they broacast at a maximum of 64K."lows and highs were better defined than those on FM radio" Sounds like you could use a Phatnoise jukebox.  I used to do alot of driving and years ago I used the most abundant highest quality recordable medium at the time -HIFI VHS.  Don't laugh, it sounds tons better than cassestes and you can fit 6 hours on a tape - perfect for long drives.  I tried DAT, but the portable was always breaking and it was a pain in the a** to edit markers and such, not to mention getting tapes.  Then I graduated to Minidisc, and now MP3 etc.

Sirius Radio PAC v4 Audio Codec?

Reply #12 –
Quote
Originally posted by Cygnus X1


Gotta hand it to them, though--at least its not WMA!!! Nothing says you hate music more than converting it to a format that leaves it sounding like it came out of R2D2


R2D2 ROFL :rofl:

Sirius Radio PAC v4 Audio Codec?

Reply #13 –
I'm going out on a limb, but how many of you actually have either XM or Sirius? By that I mean, paying for the service, not just reading what's on the spec sheet or listening for brief moments.

Sat. radio was NOT made to get the absolute best audio quality, it was made for choices in programing and convenance. If quality is the most important thing to you, then you should continue to listen to the perfict reproduction of the road noise.

I can tell you, as a everyday user of XM, I will NEVER, EVER go back to FM or ...egad, AM;) If anyone tells you FM is better than either XM or Sirius...well...that's their opinion, but I doubt they do much travling. Nothing sucks more than finally finding a decent FM channel, only to have it fade in and out, or worse end up listening to 20 minutes of comercials.:mad: Even on the XM channels that have comercials, they are limited to 2 to 4 minutes an hour.

I have the Sony unit that goes from the car to home, and from what everyone tells me, that hears XM on my home equipment or car, they like the choise of programing and can't tell any differance in sound quality over FM. I can only tell a slight difference in quality when I can actually get a FM station that is very close.

jafo

Sirius Radio PAC v4 Audio Codec?

Reply #14 –
Quote
I'm going out on a limb, but how many of you actually have either XM or Sirius? By that I mean, paying for the service, not just reading what's on the spec sheet or listening for brief moments.


I have one for sale if you want it.



Quote
Sat. radio was NOT made to get the absolute best audio quality, it was made for choices in programing and convenience. If quality is the most important thing to you, then you should continue to listen to the perfict reproduction of the road noise.


I am just disapointed, I was expecting somthing at least on par with Music Choice or DMX, but it's not even close.  Quality is important to me, that's why I'm getting a phatnoise jukebox instead.



Quote
I can tell you, as a everyday user of XM, I will NEVER, EVER go back to FM or ...egad, AM If anyone tells you FM is better than either XM or Sirius...well...that's their opinion, but I doubt they do much travling. Nothing sucks more than finally finding a decent FM channel, only to have it fade in and out, or worse end up listening to 20 minutes of comercials. Even on the XM channels that have comercials, they are limited to 2 to 4 minutes an hour.


I didn't find the content on XM that great.  The only things that I loved was the comedy station, and that you could get certain talk shows anywhere (although I preffered the sound of the AM station if one was available).  As far as the music goes well, it was OK.  As far as commercials go I found the ones on XM much more annoying than anything I've heard on the radio.  It was right up there with Cal Worthington and his dog spot.  I don't usually listen to commercials on radio that much anyway because I just flip the station.  It also seemed like they were doing much more than 2-4 minutes an hour if you count the stupid station promos that they run every couple of songs.  The DJ's were also some of the worst I've heard, it was like college radio DJ's had kids with the morning zoo.

I also didn't do enough traveling or use it enough to justify a continued subscription to XM.

Sirius Radio PAC v4 Audio Codec?

Reply #15 –
bahahhahaa go see cal! I remember those commercials