View Full Version : Radio Free Colorado is now streaming in 5.1 Channel Surround Sound

Radio Surfer
2009-09-05, 13:58
Hello to everyone,

I tuned into Radio Free Colorado yesterday and was curious about the new way Radio Free Colorado sounds, so I went to the RFC website (http://www.radiofreecolorado.net) and discovered that Radio Free Colorado is now streaming its broadcast in 5.1 Channel Surround Sound.

RFC Sounds great!


I already had Radio Free Colorado as one of the favorite Rock radio presets I listen to through my home theater Surround Sound system at home, so I experimented by listening to RFC by tuning in to their 192 kbps MP3 stream (URL shown above), and yes, RFC is really transmitting in 5.1 channel Surround Sound.

Wow, is all I have to say.

My Home Theater setup is a Squeezebox Classic connected digitally using a S/PDIF Toslink digital optical cable input to my Sony Surround Sound amplifier receiver. I use Klipsch speakers (http://www.klipsch.com) for the left, center and right front speakers and Polk Audio speakers (http://www.polkaudio.com) for the two rear channel speakers. I use a Sony 10" 200 watt powered subwoofer for the ".1" channel (not sure why they refer to the subwoofer channel as the .1 of the 5.1 Surround Sound configuration).

To me, Radio Free Colorado broadcasting its stream at 192 kbps in 5.1 channel Surround Sound is a significant internet radio advancement in technicality.

I don't know if there are any other internet radio broadcasters transmitting their stream encoded in 5.1 channel Surround Sound. I speculate that there may be others, if so I guess they would be European radio stations, but I'm not aware of them.

As it says on the Radio Free Colorado website, you can also hear RFC in 5.1 channel Surround Sound using a PC setup with the necessary five speakers. My son has this on his Playstation 3 in his bedroom.

I listened to Radio Free Colorado on my son's 5 channel gaming speaker setup which is made by Logitech. RFC sounds very spiffy on my son's gaming system also, but RFC's sound quality really comes to its full glory when I play RFC using my Home Theater Surround Sound equipment.

I say Kudos to Radio Free Colorado and to the Station Manager Gary Russell for buying the DSP broadcast processor (an Omnia) so us radio addicts that like Rock & Roll can *really* rock.

I wrote to Gary and he wrote back, telling me that he had been planning this major upgrade for Radio Free Colorado to streaming in 5.1 channel Surround Sound for quite some time. He told me he would have done this upgrade sooner, but he was busy the last two years at Kandahar, Afghanistan.

I wrote back to Gary about that, my brother is a Marine over in South Korea so I asked him why he was in Afghanistan?

Gary replied in e-mail that he is U.S. Army O-2 (First Lieutenant 1LT) and an expert in EOD (explosive ordinance device) troop instruction (Army 3rd ID, 2nd BCT information website) (http://www.stewart.army.mil/units/2BCT/home.asp).

But that now he is age 43 he no longer has to be active in overseas combat service. He went on further to explain that he used the pay he accumulated while serving overseas to purchase all new equipment for Radio Free Colorado, including the Onmia DSP processor (it's expensive! http://www.omniaaudio.com).

I am glad that RFC is back online, it was my overall favorite Rock genre preset and now it is again. So, thanks go to Gary for bringing RFC back to the internet for us radio junkies, especially us audiophile junkies like myself. :)

If you like Rock music and have a multi channel speaker setup on your PC or Home Theater setup I recommend you check out Radio Free Colorado.

And while you’re there, kick in (I did last month) some PayPal bucks to help offset Gary’s expenses for keeping and maintaining RFC on-the-air. Gary did (and still does) consider Radio Free Colorado to be a “community” radio, a listener-supported type of radio and not “commercial radio” since, uh, no commercials are ever played on RFC. :)

I do hope that enough dough comes in to Radio Free Colorado so it remains on. Gary wrote back to me after I made a $10 donation that one of the ways he measures listener's interest in RFC is by taking into consideration whether people are donating any funds to RFC.

Gary also told me that if you don't have a multiple channel Surround speaker setup (on PC or home theater), but instead only have 2 speakers playing in Stereo, don’t worry so much if you can’t afford to upgrade your speaker system.

Gary says what you'll hear listening to RFC using only 2 stereo speakers is the rear Surround Sound Channels mixed in to your 2 stereo speakers as Expanded left/right Stereo information, the Center Channel mixed in to the middle of the 2 speakers as a simulated center channel (vocals have a lot of depth and clarity that way) and also the Subwoofer channel is mixed back in to the 2-channel Stereo signal as mono, left, or right channel sound information, depending on the recording mix of the song.

Now that I understand all of this, I had no idea that 5.1 channel Surround Sound could be used for an Internet Radio station. I thought technically that 5.1 Surround was only for movies. Gary explained that electronically the RFC station electronics setup is about the same as the electronics used for encoding 5.1 sound channel Surround Sound used for Dish Network, Cable TV, etc.

I'm impressed. Thanks Gary. :)


P.S. If you’re interested in what work Gary was doing overseas, Gary recommended a particular book to me. Here is a URL link to an Amazon.com books page: Eight Lives Down by Chris Hunter (http://shrinkify.com/16c1).

In looking over the book Gary recommended to me (Eight Lives Down), now I understand why sometimes it seemed that Gary was definitely around at RFC running things, and why at other times it seemed he wasn’t. It is because he couldn’t be in two places at once.

Here is a link to a photograph Gary provided to me of him in Iraq in 2005: http://www.boomspeed.com/garyburke/Gary_in_Iraq_in_2005.jpg

2009-09-05, 15:01
Very interesting.

I may have missed this in your post, but what is the source material they are broadcasting? Native 5.1 mixes of music (not very many), or are they doing some pseudo 5.1 from stereo material and then broadcasting that out?

2009-09-05, 15:03
I guess RFC is just using DPL2 encoding on their stream?

2009-09-05, 15:11
I guess RFC is just using DPL2 encoding on their stream?

If that is the case, wouldn't one achieve the same/similar results from engaging DPL2 on their receiver or pre-amp?

Radio Surfer
2009-09-06, 07:27
Gary sent me a message tonight snipped from the site http://www.hometheaterforum.com:

"DPL II is a decoder only. It works with any 2 channel stereo source whether surround encoded or not, although you will get better channel separation on Dolby Surround encoded material. DPL II works with the same Dolby Surround encoding as the original Pro Logic, but instead of a frequency limited mono surround, you get full range stereo surrounds."

To forum member’s SAM's post here, I asked Gary at RFC about what you said:

"If that is the case, wouldn't one achieve the same/similar results from engaging DPL2 on their receiver or pre-amp?"

The answer RFC e-mailed to me SAM, and from what I read on the internet tonight about Surround encoding on the Dolby and other manufacturer's web sites is that the audio material (live streamed or not) needs to be encoded into a 5.1, Dolby Pro Logic II, Dolby Live, DTS, etc. format for a true stereo Surround effect and Center channel effect to be achieved. (Dolby is not the only encoder brand type, just the most well known).

So, SAM from what I think I now understand is that "engaging DPL2 on their receiver or preamp" as you said, is only half of the pairing.

When you engage (you mean turn on?) a certain surround setting on your equipment, you are turning on the decoder portion (one half) of the surround sound encoding equation. RFC is doing their part at the source by providing the encoding portion of the surround sound equation, or the first 1/2 of the equation of the surround encoded stream.

Gary said to me what is going on with this new RFC stream is a Surround Sound "Codec" is being used by RFC which is then embedded into the MP3 stream.

Codec is a technical jargon abbreviation for "Coder/Decoder". "Encoders" apply math to encode the signal source, then the Encoded signal is followed by or sent to a "Decoder" which applies its own math to decode the encoding. The decoding could be done by a device connected by analog audio cables, a device connected by a Digital audio cable connection, a device connected to a Cable Television receiver or even from a Satellite signal.

So, RFC's 5.1 channel stream (or other sound material encoded in a surround format) is the source part of the "Codec", it is the "Coder" part. Or, consider it the 1/2 of the Codec signal that is provided to you. Then, it's up to you to decide what is the most pleasing, compatible or best sounding Decoder setting to use at your end.

Activating certain surround decoder settings on your receiver or preamp provides the latter 1/2 of the source’s "Codec", the Decoder, meaning your selected Surround Decoder is providing 1/2 of some type of mathematical solution to the "Codec".

Essentially the surround encoding by RFC is embedded into their 192 kbps MP3 stream. This is all possible since some current Dolby encoding is “packaged”, or carried within an AAC stream of varying bandwidth instead of MP3. I think I read somewhere that Cinema quality DTS uses a PCM bitstream.

Gary told me the reason Dolby usually packages their surround encoding within an AAC stream instead of MP3, MP2 or WMA has to do with minimizing monetary royalty payments to non-Dolby patent holders.

Gary said when he monitors RFC he uses the 5.1 setting on his Home Theater system and prefers the sound that way, but that your results can vary because his Home Theater system uses: "full-range tower speakers for the front left/right speakers and a large center channel JBL dialog speaker. His left/right front speakers are mated to a Velodyne powered subwoofer with its crossover set to a 6 decibels per octive bandpass slope beginning at 200 Hz" (quoted from Gary).

When I activate the Surround setting on my Sony Home Theater system, doing an A/B comparison to other radio stations (FM and Internet) and then listening to Radio Free Colorado as the signal source, to me the sound just leaps out and fills the entire room with better surround imaging and clarity.

Gary said the Omnia DSP unit and mating software package being used at Radio Free Colorado can and does mathematically derive separate stereo, full-range surround for all channels up to 5.1, whether the original source material RFC plays is surround encoded or not.

Finally, I asked about 7.1 encoding, etc. and the reply I received is that Gary felt any encoding of Radio Free Colorado's stream beyond 5.1 channels would be overkill.

I agree, since I have the "wife" factor to deal with, adding more speakers to the living room would cause marital distress. :(

Personally I find what Radio Free Colorado is doing fascinating.

RFC is still experimenting with the encoded sound level of the Subwoofer channel.

Also I note in my listening to RFC that older songs, or poorly recorded songs are more easily noticed now than before. Songs with better recording quality, some of which I own on Compact Disc, sound much better on RFC than the poorer sounding songs which have a bad mix, tape hiss, etc.

I suspect this is because of the RFC stream being at 192 kbps MP3 instead of 128 kbps MP3, the 192 kbps MP3 stream being more “revealing” and open in clarity. So, if a song sounded OK encoded at 128 kbps MP3 but has noticeable flaws when encoded at 192 kbps MP3 this is an expected occurrence. The lower bitrate streams can mask imperfect song recordings.


2009-09-06, 18:52

Thanks for providing a thorough background on what RFC is doing.

However, I think my original point still stands: if the original source material was mixed/recorded in 2.0, you are really getting only a facsimile of true 5.1 surround sound. This can be achieved via the encoder method as you described (subsequently decoded by a Dolby Digital surround receiver), or via a decoder like Dolby ProLogicII.

Regardless the result is the same. If you take "Stairway to Heaven" and RFC encodes it using a the Omnia DSP to 5.1, the end result (decoded) is essentially the same as if you take the same song via regular 2.0 CD and decode it via Dolby ProLogicII/DTS Neo:6 Music/etc. You are getting a facsimile or "fake" surround sound. True 5.1 would only come from remixing of the original session tapes to a discrete 5.1 mix.

Too bad RFC doesn't have access to broadcast some of the natively-mixed 5.1 material out there...

Radio Surfer
2009-09-10, 01:12
Hi Sam,

I am curious, how do you know RFC does not have access to 5.1 Channel material?

Are you certain?


2009-09-10, 04:59

If they had native 5.1 material, wouldn't they make mention of that? Seems like a huge selling point.

The other indication that the source material is stereo comes when they share this information:

Gary said the Omnia DSP unit and mating software package being used at Radio Free Colorado can and does mathematically derive separate stereo, full-range surround for all channels up to 5.1, whether the original source material RFC plays is surround encoded or not.

I'm not trying to bash RFC. I'm just trying to clarify for everyone reading here that the title and discussion about broadcasting in 5.1 is a bit of a misnomer. Yes, they are broadcasting in 5.1. But, unless someone clarifies for me otherwise, I get practically the same 5.1 effect if I take the any stereo-originated program in the world and engage the Dolby PrologicII button on my receiver. Now I have "separate stereo, full-range surround for all channels up to 5.1" just like RFC claims.

2009-09-10, 10:03
For anyone interested in making a donation to RFC, I would say, "Buyer beware." See http://forum.wheresgary.org/viewforum.php?f=15.