Ads on TV are indeed louder than programmes
Some tests to prove it
Since ads first appeared on TV, viewers have claimed they are louder than the programmes.
Quickly, TV spokespeople are wheeled in to ardently deny it. In summary, they will state that the maximum sound levels are well controlled and then insist that ads are no louder. Such a statement contains one fact and one serious economy with the truth. Yes, peak levels are well controlled because transmission systems are quite intolerant of excess peak sound levels. However, that has very little to do with loudness as a human listener perceives it. Listener perception is governed by average levels integrated over 250ms to 400ms intervals. (1/4 to 2/5ths of a second). I have known for many years that average sound levels increase dramatically during ads, but now it was time to make some measurements to show just how bad the problem had become.
I made a number of measurements from three of the free broadcast TV stations available in my area. I recorded about 1/2 hour of each in the early evening, then analysed the sound levels using Cool Edit Pro on the pc.
Summary of results
It became very clear that TV ad breaks (including self-promotional spots and trailers) have higher sound levels than programmes. I measured all the individual ads within the recording period; many are as short as 15 seconds in length, but all were louder and the vast majority of these ads were much louder than the programmes.
The technical part
The first part contains a table for each of the three TV stations. Recordings were not synchronised to any particular time, so some start during programme material and others during ads. The duration of each is close to half an hour. Many interesting things can be seen from the tables. First a description of each column.The first column has a brief description of each segment.
Column 2 just states whether any stereo content was present.
Column 3 is the time in seconds for each segment.
Column 4 lists the peak volume (in decibels)relative to the loudest peak in the whole recording.
Column 5 lists the average recorded rms level (in decibels) below the peak level.
Column 6 lists the maximum rms level (in decibels) below the peak level.
Column 7 lists the minimum rms level (in decibels) below the peak level.
Column 8 lists the ratio of the maximum to minimum rms levels. Lower values sound louder.
Finally in Column 9, an index I have called the annoyance index has been calculated, using a proprietary algorithm which is scaled from 0 (no annoyance) to 100 (extreme annoyance). This index is based solely on audio levels and has nothing to do with content. It is also a slight simplification because it is not weighted based on frequency bands. Nonetheless, I guarantee that you will find anything above a rating of 75 very annoying indeed. Such ads make you reach for the mute control very quickly or even quelle horreur, change channel!
The purple shaded rows are programmes and anything else is ads. Orange shading in the last column means the item is above the very annoying threshold of 75. 13 of the 22 ads in this half hour are very annoying in volume. Notice that this station controls peak levels well; all are within 2dB of each other. Peak levels made practically no difference to the annoyance index. The most annoying ads have lower peak to average ratios and a lower range of rms levels. The max/min ratio column is the most telling. Low numbers here are more annoying.
This recording had 32 ad events within the half hour period, 15 of which rate as very annoying in volume. Note that the three programme events (purple shading) have a low annoyance, meaning they have a much greater range of volumes from low to high. Again, note the range of peak volume level is very small showing just how irrelevant it is to the perceived volume.
Of the 17 ad events in this recording, 10 rated as very annoying. The peak volume has the most variation of the three stations but see that the one with the highest peak level is a programme segment with a low annoyance index.
It is interesting to see just how many ads and promos are squeezed into the gaps between programme segments. I should add that I have not included the ad quantity into my annoyance index. Perhaps I should.
Graphical presentation on time scale
Following are three graphs of the same recordings, showing peak level to average rms ratio (blue lines), max rms to average rms ratio (red lines) and max rms to min rms ratio (green lines) on the upper graph and my annoyance index (black lines) on the lower plot. Because the audio plots are all ratios, the lower the ratio, the more annoying is the sound. It ought to come as no surprise that the ad breaks all have much compressed rms levels and most ads rate as much more annoying for their volume than do the programme segments.
Easy to spot ad breaks here. There is one ad that is only slightly annoying though.
And a couple of tolerable ads here too.
And not surprisingly, ad breaks are easily spotted for this channel too; all rate annoying in volume.
Why do broadcasters do this? It is because they have this idea that the message will stand out if punchy and loud. They are really at the mercy of the advertisers, who supply most of the ads anyway. They do run the risk of turning off viewers and they really should have the maturity to understand this. At the very least, viewers will hit the mute and they will often change channels. Why would broadcasters continue to alienate viewers in this fashion, especially in modern times when traditional TV audiences are falling.
Axino-tech October 2009