Has anyone added HD radio to their GC?
Which brand?
Howz it workin?
Thanks!

Great question, anyone?

HD Radio is nothing special. If you have Satellite Radio...then you have "hd radio" with a fee.

The overuse of the "High Definition" moniker disgusts us RF guys.... it's nothing more than a digitized, compressed, lossy FM signal. There are 3 channels, a Carrier Wave (the same as used by FM radio!), the HDC channel with digitized music thats HIGHLY compressed, and a third that can carry some form of RDS or text.

The cool thing is, however, that it will be free. This whole HD Radio branding is really being pushed by the company that owns the technology, so they are trying to sell you on the idea.

Here is a breakdown of what the average person needs to understand:

FM = shotty signal, not much information contained, VERY limited frequency range.

Satellite = "near" CD quality, unlimited bandwith so quality will improve, high fidelity slightly compressed signal

HD Radio = "near" CD quality, very lossy compressed signal, very limited channel choice, still in early stages. Less signal quality vs. Satellite, less dB gain.

Uhhh...my satellite radio is nowhere NEAR CD quality. I heard it's only like 96 Kbps...nothing near 192 or 256. I thought HD was much different from satellite. Can you help disspell the myths I have been hearing?

Uhhh...my satellite radio is nowhere NEAR CD quality. I heard it's only like 96 Kbps...nothing near 192 or 256. I thought HD was much different from satellite. Can you help disspell the myths I have been hearing?


Easy to dispell. You are assuming all compression standards are MP3, when in fact MP3 encoded material is among the WORST compression techniques out there.

CD Quality compression utilizes PCM encoding, direct digital where every bit is held intact.

For satellite radio, the sample rate is 48 kbps. They use a compression algorithm called CT-aac PLUS.

FYI...CD's are of 44.1 kbps, 16-bit PCM. :)

Easy to dispell. You are assuming all compression standards are MP3, when in fact MP3 encoded material is among the WORST compression techniques out there.

CD Quality compression utilizes PCM encoding, direct digital where every bit is held intact.

For satellite radio, the sample rate is 48 kbps. They use a compression algorithm called CT-aac PLUS.

FYI...CD's are of 44.1 kbps, 16-bit PCM. :)


Then why do CD's sound FAAARRR superior in my car than the radio [quality, not just volume level].

Because it's a DIRECT conversion bye the stereo equipment, with ZERO loss. There are DAC's inside your stereo headunit that do the conversion, and the signal dosen't have to travel very far or have to fight it's way through tree's, solar energies, clouds, or travel hundreds of miles to get to you. :)

CD's from a headunit are converted directly by the radio, on the spot, then delivered to your speakers.

Satellite radio is still a compressed, transmitted signal with loss. HD radio, same thing. CD's will always sound superior because its a direct translation using PCM digital audio.

Awesome thanks for the explanation!! :)

:D Mango knows his stuff!!! nice to have someone like this on our board. I do think that Satellite sounds far better than F.M. radio.

There is A LOT more to it than what we are discussing here. It is far beyond my knowledge level, but I can tell you this: even my mp3s and regular FM sound FAR superior to even my XM. The HD radio in my friend's new M5 sounds soooo clear its hard to believe its being transmitted via radio waves.

BTW - I cancelled my XM service because they compress it so much and so poorly.

Because it's a DIRECT conversion bye the stereo equipment, with ZERO loss. There are DAC's inside your stereo headunit that do the conversion, and the signal dosen't have to travel very far or have to fight it's way through tree's, solar energies, clouds, or travel hundreds of miles to get to you. :)

CD's from a headunit are converted directly by the radio, on the spot, then delivered to your speakers.

Satellite radio is still a compressed, transmitted signal with loss. HD radio, same thing. CD's will always sound superior because its a direct translation using PCM digital audio.
A digital signal is not going to experience signal degradation like analog radio waves. The reason it sounds less than par is because there is limited bandwidth allocation for the satellite signals to utilize. Therefore Sirius, for example, can only use a predetermined amount of bandwidth in which to transmit its digital signals. It must compress (thus incorporating perceived signal loss) all of its signals before they are transmitted. I am hoping, actually praying, that the XM/Sirius merger combines the total bandwidth usage and reduces the compression they are forced to use. Correct me if I am wrong.

I am just trying to explain things as clearly as possible, and surely there is MUCH more to it than just what I'm saying.

The merger would not enable the companies to "combine" bandwith, since it's broadcast over many different satellites over large areas.

A "digital" signal, such a HD Radio and Satellite Radio, DOES experience signal loss. Every form of radio wave does. The difference is, digital signals are HIGHLY COMPRESSED and broadcast at a higher output range, over a higher frequency range, and thus are considered much more "robust".

A radio wave, is a radio wave, is a radio wave.....FM waves are typically in the 400hz range, very large and very "long" physically. They can travel great distances but cannot contain much information. Thus, FM sounds like it does.

HD radio and satellite radio are transmitted "digitally" at the source, using very expensive equipment and at a high frequency range! Thus, they need to utilize ground repeaters (XM and Sirius use ground based repeaters all over the country and in major citities such as NYC, Philly, etc.) because line-of-sight is important for digital signals. If your car is surround by tall buildings, your Satellite radio is drastically effected.

HD Radio will eventually be wide spread, because they can piggy back on existing ground repeaters, can transmit EVERYWHERE and it's free and nearly CD quality. It sounds better in most cases because our existing network of FM stations and repeaters is already in place, so covereage is EVERYWHERE. Stations just need to update thier hardware and we are good to go.


FYI: I've been working in the broadcasting industry for many years, as an RF geek/technician for NBC Sports. This is my summer job. hehe.

My Dad's been in broadcasting for many...many years.

But why does HD sound better than satellite for BBLV???

Ok, y'allz...this sounds good BUT anybody got HD radio in their GC SRT8?
Sirius radio aint worth it except during NFL season...

I'am also in the broadcasting industry and interested in HD FM Radio for my GC, our engineer sugested a $200.00 universal hd converter available from Crutchfield.com that connects to the factory radio.

I'am also in the broadcasting industry and interested in HD FM Radio for my GC, our engineer sugested a $200.00 universal hd converter available from Crutchfield.com that connects to the factory radio.

I too am interested in HD radio for our vehicles. I have an HD radio receiver at home, and I'd happily dump my sirius service for it (I do listen mostly to AM talk radio, and the difference between AM analog and HD digital is beyond description!).

Like others have said HD radio is not really HD its a name or trickery as I like to call it! and I have sirius in two of my vehicals and LOve it. I really do not think that it is even close to the quality that HD radio is.
and yes thanks to people like Mango is why this forum is so great !