AES Journal Forum

Very interesting article, my observation and other listeners to an overcompressed local FM station is that it is fatiguing to listen to for more than a few songs. However it is the highest rating FM station. Could it be it is popular for background noise,rather than music listening or do people really like constant levels. Your research would show people prefer some dynamic range. maybe the music appeals to more people on that station, be interesting to know how long the average listening time is compared to the classical music station

A great article, and I'm glad to see others recognizing the problem.

The loudness war is the main reason I stopped listening to FM radio.

I've also found that many stations over-equalize the DJ's mic.

With the adoption of the ATSC A/85  and EBU R128 standards for Loudness in broadcasting, I really wonder whether we'll see some relaxation in the "race to the bottom" with overcompression. Earl gives the example of how hard it is to compare two different pieces of programming, with regards to their degree of compression, when the content is the overwhelming determiner of listener preference. Yet it would seem that unwelcome volume changes have fostered this legislation (the CALM Act, etc.), so listeners are obviously affected by changes in level. Notwithstanding, the audibility of compression to the average listener remains elusive - it's not like the human hearing mechanism is as adept at sensing electronic intervention/manipulation of dynamic range, as it is with sensing pitch, timbre, source direction, etc.

I, too, would like to see further research into any possible correlation of over-compression and hearing damage. Also, I would like to see some further discussion as to just what constitutes "listerner fatigue".

I find over compressed radio stations fatiguing and I miss the dynamic range I used to hear on some Australian TV stations. I don't miss loud commercials or station promotions though. Even on a radio station with compression (an old Aphex Compellor and Dominator) I have heard the comment that the announcers often sound lower level than the music and other level vary. I don't know if this is a function of over compressed Contemporary Christian music recordings or signs the Compellor and Dominator are not as good as they used to be. Another station with the same processors that plays jazz, classical, folk, world and very little pop does not have this problem.

I think Frank Lockwood's call for more research is valid, as I said in a previous post the most ovecompressed FM station in Canebrra is the highest rating as is the ABC (compressed) AM station, and people still watch and listen to TV.

A few comments from one who has been there . . .

First, highly compressed audio does not necessarily equal high loudness. CBS Laboratories investigated this phenomenon in the 1960s and manufactured the Volumax*. Audimax* and Dynamax*to increase loudness of certain program material on radio stations. I would refer you to the AES papers on the subject. You can search for them yourself. My extremely short "executive summary" of their findings was that frequency balance was also important. Merely compressing the bejeezus out of the program material did not necessarily result in high loudness for all program material. I remember installing a system in a radio station where the Dynamax hardly ever worked. But every time "A Horse With No Name" by the group America played, the needle on the machine just went from full left to full right. Immediately. And the frequency balance ended up sounding the same as the other program material which did not "excite" the Dynamax*.

Some years later I worked in the Engineering Department at United Recording Electronic Industries (UREI.) We were asked by the United States Information Agency to design and build a custom product for their shortwave transmitters, primarily in the US. It ultimately consisted of a fast attack/release RMS compressor followed by a fast attack/release high ratio limiter, followed by a peaking and high slope cutoff filter specifically for the bandwidth they required. This was then finally followed by an adjustable diode peak-clipper to remove anything that had gotten past the compressor or limiter and to remove overshoot artifacts introduced by having the filter follow the limiter. When you were done, the level was extremely consistent, normally within a dB. Note that the use was almost entirely voice material, and the purpose was to allow their million watt transmitters to send the signal thousands of miles. I listened to some music in the lab and it didn't sound too awful (subjective assessment) until the peak clipper was dialed in more than about 6 dB. Then it sounded terrible. In actual use, on their program material, they were extremely happy with the results.

Lastly, I am a member of the generation whose hearing has been damaged by loud audio. I worked 5-6 days a week for several years in the 1960s as a sound man in several venues where we were pretty consistently running 120dB C-weighted at 100 ft. from the stage. I find that certain television stations have a reasonably wide dynamic range on program material, but that I have to madly grab for the remote control to turn down the volume during commercial breaks. I hope that the new standards Mr. Lockwood references will be helpful, in a manner similar to what happened to the level of trailers vs features in motion picture theaters following adoption of a Standard there.