This enquiry is an extension of the "HD-4-5-6... ??" thread -- sort of, but not really, since that thread has gone in the direction of "extended hybrid" digital broadcasting.

According to iBiquity's online database, about 30 stations are transmitting HD3 multicast streams. (No mention of HD4s or higher.) I presume these stations are splitting the basic 96 kbps into three segments, although some of them may be using extended bandwidth. A number of stations in my market have HD2 but not HD3, so I have never heard the quality of a stream slower than 48 kbps. I've read NPR's research that found most listeners were unable to distinguish between the quality of a 96k and a 48k stream, but some people complain of digital artifacts when the bit-rate drops below 64k.

So, how do the HD3 streams sound? Several stations are running classical and jazz formats, whose listeners generally are quite discerning. If anyone on the Forum has access to these streams, I would appreciate your thoughts about their audio quality.

Thanks!

Well AM HD is 32kbps, and many say it sounds "great". For news or talk programming, particularly in mono, 32kbps should be just fine with AAC+. It's a very efficient codec. Now I'd be skeptical of stereo at 32kbps!

I've added HD-3 to a couple of my stations.

Sound quality is such a subjective thing. I hate to comment.

I will say, I added the HD-3's in extended hybrid mode...because I didn't wanna decrease the quality of the programming on the primary channels.

In our case, the HD-3's are both News/Talk, so running them at 24k is acceptable...sort-of.

Dave O.

In Atlanta, WSTR seems to have quit multicasting, so the only station left with an HD-3 signal is WABE. They are using the third stream for NPR news. It sounds fine. Their HD-2 stream is classical music, sometimes a simulcast of their HD-1 program with a slight time delay, but usually a different program. It also sounds fine. The HD-1 program is, of course, a simulcast of their analog program which is sometimes locally originated classical music from recordings, sometimes concert recordings from Atlanta venues, some syndicated programs, such as Chicago Symphony Retrospective, and a lot of NPR and APR programming, such as All Things Considered, Pairie Home Companion, etc. Kudos to CE John York, all programs sound fine and also stream over the Web for those poor, benighted souls who do not yet have HD receivers.

Picspop:

Just wondering, is WABE running their HD-3 in extended hybrid mode (like service mode MP3)? Or just carving up the main HD bandwidth in three parts (service mode MP1)?

Thanks,
Dave O.

Dave, according to my tuner, the transmission mode is MP1. Does that answer the question?

Well AM HD is 32kbps, and many say it sounds "great". For news or talk programming, particularly in mono, 32kbps should be just fine with AAC+. It's a very efficient codec. Now I'd be skeptical of stereo at 32kbps!
Actually AM HD is 20kbps since most AM stations are mono. 32kbps is for stereo.

Speaking of bitrates...Do any of the HD radios have the ability to show the current bitrate? I was suprised that with all of the great detailed info the HDT-1 gives...that bitrate was not available (unless I'm missing something).