Many thanks to SWLing Post contributor, Roseanna, who shares the following announcement from Radio Northern Europe International:
Hello everyone,
Last broadcast was pretty successful with many wonderful reception reports and some people sending in decodes of the stereo which is amazing to hear!
A reminder to go to https://rnei.org/stereo/ to learn how to decode the stereo, it is real stereo over a mono shortwave transmitter!
RNEI show 4 is half dedicated to Eurovision entries so the first half of the show is an entery from each Nordic country and after that we take a trip to some Faroese and Irish traditional musics before ending with our favourite Eurovision entry from this year and the final song containing the MFSK 32!
TIAMS has made another 30 minute express music show for after our broadcast for you to enjoy!
Click here to continue reading the announcement and view the full RNEI schedule.
Hi,
We did think about DRM. If you listen to what people actually are broadcasting on DRM it’s much worse sound quality (usually <20kbps audio which sounds terrible on music in mono nevermind stereo) than CombStereo + digital post processing. The licence fee is thousands to broadcast on DRM too and the much bigger issue is that it is not backward compatible.
We believe any fun experemental and enhancements shouldn't affect existing listeners! Our standard is fully mono receiver and transmitter compatible unlike DRM.
Don't bash it until you've heard it: https://youtu.be/dt_FwJMSsV0
Roseanna,
Comb Stereo was patented in 2006 https://patents.google.com/patent/WO2008064050A2/en so by now I would have expected most AM broadcasters to be using it.
I listened to your sample to find that it does not have much separation so I cannot hear something on the hard left or right. It also contains the phasey effect you get from multipath reflections from the ionosphere, which can be heard on AM in both medium and high frequency bands.
I live in an area where DAB+ using HE AAC compression, commercial broadcasters have been reducing their bit rates for stereo music down to 32 kbit/s and the stereo contains hard left and hard right sound, the high frequencies are slightly distorted.
It is important that the original sound was not MP3 compressed first then converted back to analog prior to another lossy compression in the content server prior to transmission. This wrecks the sound quality. There are companies making music libraries from either CDs or the original master tapes which are not compressed. This eliminates the phasey effects regardless of the bit rate.
DRM specifies the use of xHE-AAC compression which is much more efficient. Listen to the quality comparison on headphones https://www.youtube.com/watch?v=SGLBKz9Q_XQ This compression is subject to patent costs to Fraunhofer who developed it.
Talking of costs have you seen https://www.drm-sender.de/ You are using an AM transmitter, the DRM handbook is about to be upgraded but in the present edition it mentions upgrading https://www.drm.org/drm-technical-specification/ from page 44
Thanks for innovating
“Thanks for innovating” indeed! 🙂
I think the concept of Combe stereo is fantastic.
While I think DRM has a lot of merit, it does require a DRM-capable receiver and unfortunately only a wee fraction of shortwave listeners have one. If you’re paying for airtime and want as many listeners as possible, unfortunately DRM is not the best option at present. Folks without DRM receivers can use the KiwiSDR network, but it requires an internet connection.
What I love about Combe Stereo is you can listen to the broadcast normally, or give the stereo effect a try if you feel like experimenting. Why not!? 🙂
Thanks, Roseanna, for putting your show out there for us to enjoy!
Cheers,
Thomas
Good try, but DRM can transmit parametric stereo which is a mono digital stream with a much lower data rate steering signal which gets the receiver to move the sound left or right.
DRM is standardised to transmit digital sound including stereo from 153 kHz – 230 MHz, with above 47 MHz surround sound is also included. Data is also added.
The big advantage of DRM in the high frequency band is that there is no carrier which is 67 – 100 % of the transmitted power which does not contain any sound.