Radio Production 101

My understanding is that AM stereo actually broadcasts in higher quality than FM.

Well, if you call a bandwidth extending all the way up to 7.5kHz better than the 15kHz that FM manages higher quality, then I suppose that it is...  

I have heard this before as well.  But it's always those RF engineer types that say it.  Must screw with their brains after prolonged exposure.

My understanding is that AM stereo actually broadcasts in higher quality than FM.  I was always told that AM's poor quality is a result of broadcast and reciever equipment, not the nature of AM broadcast.  I've also heard that, with the advent of HD, music stations will likely move over to AM to get the increased coverage area.  I know of two 50,000 watt AM stations that reach almost all of the US at certain times of the day.  I would imagine that after HD catches on, those frequencies will be worth a fortune.

No in actuallity the HD signal is somewhat smaller in coverage area than the regular broadcast one so there won't be a mad rush for AM. However HD will give AM a better sound than it does have now, but YMMV. AM due to its naure of the way the signal is is more prone to interference than FM. A properly maintained AM transmitter is a true science and somewhat difficult task ask any radio engineer. There are a few 'clear channel' (not the company) stations like the 50,000 watter you mentioned, but not many as it used to be. In fact there has been a reduction of the number of AM stations over the last 20 years and what remains are either news/talk/sports stations or religious/spanish etc channels. Very few music only stations are around on the AM dial.

Stereo AM also comes to mind. There are some stereo AM stations in the US right? Or if there aren't now there used to be. Something that has never to my knowledge existed in the UK and I could never understand.

There are a lot of stereo AM stations in the US, and you could entirely be forgiven for not underanding how AM stereo works. Here is a 'simple' explanation...

Why don't we have stereo AM in the UK? It IS here in Europe isn't it?

And, can someone explain the "HD" that's being mentioned in this thread please.

HD means (from Ibiquity the makers of the IBOC or In Band On Channel digital radio system here in the states) High Definition. I personally have not heard it, but it is said to sound much fuller (and has the full 20k frequency response) sound than conventional FM and also helps in multipath situations. Although I think it will be mainly a multi-channel (i.e. formats) format for stations to gain added revenue rather than cleaning up their exsisting signal. For everything on HD Radio see this link http://www.ibiquity.com/hdradio/.

I had no idea that 3 stations I listen to frequently have this on the air.  Thanks for the iBiquity link!

I have heard both AM & FM HD over the air.  My impression is that FM/HD was not much different from Analog FM.  AM/HD is another story. It takes about 10 seconds for the radio to lock onto the digital signal, when that happens it is like going from a tiny transistor radio to a really good home stereo system.  The "wow" factor is huge.  There are certainly plenty of pro and con articles about the US conversion over to HD radio and I'll let the engineers debate that.  From my standpoint as a radio producer I look at it as another avenue to bring more creativity to my job.  Here is a link to a fine site that covers radio news in the Northeast US.  http://fybush.com/nerw.html  In this weeks edition there is a lot of info about HD and what stations plan to do with it.

I had no idea that 3 stations I listen to frequently have this on the air.  Thanks for the iBiquity link!

You're quite welcome! Stations will denote that they are broadcasting in High definition radio, but this is slightly incorrect according to iBiquity leagalese. For the latest on the subject of radio check out http://www.beradio.com/. I subscribe to their print magazine (btw its free if you are in the business). It's more on the technical (engineering)side of radio rather than a management side, but a great publication.

Why don't we have stereo AM in the UK? It IS here in Europe isn't it?

Well, there's Radio Bleu... and you find out some more from the links on the site - but I don't think that it's particularly good news.

OTOH, I know where you can get a complete C-QUAM AM stereo processor for your AM transmitter for about £2000 in the UK. I bet they don't sell a lot, though...

HD means (from Ibiquity the makers of the IBOC or In Band On Channel digital radio system here in the states) High Definition. I personally have not heard it, but it is said to sound much fuller (and has the full 20k frequency response) sound than conventional FM and also helps in multipath situations. Although I think it will be mainly a multi-channel (i.e. formats) format for stations to gain added revenue rather than cleaning up their exsisting signal. For everything on HD Radio see this link http://www.ibiquity.com/hdradio/.

I haven't heard HD either, but my engineer wasn't impressed with it.  He said it sounds about like a 128kbps mp3.  He also said the sub-channels divide the bandwidth, so with one sub-channel, the quality of both channels sounds about like a 64kbps mp3.  So, until the technology improves, none of our music stations will have sub-channels.

No offense meant guys but some of the filters arn't all that accurate.

They do use the "telephone" sounding effect but only once in a while

I believe topic started asked about Chad Erickson...  So here's his VO

First is dry, nothing done with the voice.
Second is one kind of filter (this isn't a preset)
Third is a different kind of filter.


The reason why these are the most popular sounds are because they bring out the highs and lows without drowning the VO.

They're quite subtle aren't they?

Good lord he uses a lot of compression on his "dry" reads.  What is that, about 8:1, you think?

No compression on the file... I'm sure he's got his compressor cranked up though

HD means (from Ibiquity the makers of the IBOC or In Band On Channel digital radio system here in the states) High Definition. I personally have not heard it, but it is said to sound much fuller (and has the full 20k frequency response) sound than conventional FM and also helps in multipath situations. Although I think it will be mainly a multi-channel (i.e. formats) format for stations to gain added revenue rather than cleaning up their exsisting signal. For everything on HD Radio see this link http://www.ibiquity.com/hdradio/.

For those outside the lower 48, HD Radio/IBOC looks to be a US only system.  Europe and UK use L-band for DAB, something that the US military refused to give up, though they don't use it much.  Here in Canada, I was under the impression that we were going L-band as well, but that may have changed.  All this North American DAB/HD/IBOC stuff has been under test and discussion for what seems like 20 years now, and the IBOC stuff has come from being horrid what it is now.

The one thing the electronics industry seems to have forgotten, given the success of CD players, is how people listen to the radio.  Not everyone listens at home on a system that allows easy plug in access like a home stereo.  People listen in their cars generally, and when's the last time you tried to take everything apart to replace a radio?  Given the satellite radio example, I don't think that consumers are in a rush to go out and replace their radios any time soon.  I think the next big thing in radio might be the FM adapter for I-Pods, and making the I-Pod the center of your audio entertainment.