Have you ever noticed that the ads on commercial television seem a lot louder than the shows? While it would be difficult to vanquish ads alltogether from our tv screens, perhaps we can plug the startling gap between quiet soap opera, and noisy man in a slick black suit trying to sell me stuff.

Studio producers have long used devices (I think) called compressors, to normalize the sound of tracks. No matter how good the musician, not every note played will be of equal volume even when it is intended to be so. By normalizing the performance, a producer (to a degree,) can keep the entire performance at a constant volume.

If a compressor could somehow be attached to a televison, where the viewer can choose the volume, and the variance in the volume they want, they could in theory, eliminate the startling loudness of ads by normalizing them to the volume of whatever show is being watched.
-- sdm, Jun 26 2001

DIY Audio compressor http://www.paia.com/encompr.htm
Bake it yourself. Put one of these compressor/limiter widgets between your receiver and your amp. [rmutt, Jun 26 2001, last modified Oct 04 2004]

// ...the viewer can choose the volume... //

My TV can already do this. Baked ???
-- lubbit, Jun 26 2001


I think [lubbit]'s missing the point. The 'compressor' part of the idea is so that you can set your preferred volume level and a highest and lowest range. If an ad has SHOUTING in it, which is louder than your pre-set 'highest' limit, the device limits the volume. Similarly, though in reverse, for very quiet passages.
I always mute ads anyway, so it doesn't concern me.
-- angel, Jun 26 2001


so that's what that feature on my tv does. Either my owner's manual doesn't explain all of the features on my television, or i didn't bother to read it. probably the latter.
-- juan2003, Jun 27 2001


Compressor/limiter is used to constrain the dynamic range of a soundtrack (quiet is louder, and loud is quieter--the RCA Sound Logic Control mentioned above is, in fact, a crude compressor limiter).

Devices specifically designed and used to increase the apparent loudness of a soundtrack are often called aural exciters. They work using a variety of methods but the end result is that the track sounds much louder but, in fact, has no greater electrical signal strength. It is very difficult to gate or filter this at the receiver end because it is a psychoacoustic effect rather than a machine measurable effect.
-- lummox, Jun 29 2001


Aural exciters are also used in stomp box effects for electric guitars, presumably to seem louder without inducing feedback -- and I suspect that the most effective response to most commercials is the Mute button on most recent remotes (even my grandfather had an audio-kill switch called a "Blab-Off" on a long cord). Sometimes I kick in some Frank Zappa or Bonzo Dog DooDah Band as a more interesting soundtrack.
-- whatsbruin, Sep 07 2001


Hi all. This is my first response so please bear with me. Actually I am really not a DJ at all but rather a skilled part-time sound man. Just wanted to set the record straight with some of the more distinguishable audio gear:

COMPRESSOR: A compressor is a device which gently "tames" the amplitude dynamics of an audio signal over a broad logarithmic curve based on Input signal versus Output signal. The important detail here is that an (adjustable) MAJORITY of the audible dynamics are affected. Therefore, average-volume sounds are affected as well as high-volume sounds. The softer sounds just aren't "tamed" or treated as harshly. This is useful as it produces a "realistic" or proportionate sound. When adjusted properly, the compressor won't do anything to the softest sounds. The user will often increase the output volume of the compressor, thus bringing up the level of softest sounds.

LIMITER: A limiter in theory is quite similar to a compressor. The important detail here is that the response curve of a limiter is extremely sharp. It only reacts to the loudest of signals. When activated, it kicks in, crushing the amplitude dynamics to an absolute "limit", henceforth called a "limiter". It is generally used for system protection (peak-limiting)rather than creative purposes (as is the compressor).

NORMALIZER: A different device yet! This is what would make the most sense for application in a TV set. Essentially it is the audio equivalent of a servo-drive system. The output level is monitored through internal feedback circuitry and is controlled by being matched to a reference level (depending on the device this level can be adjusted). Unlike compressors or limiters, it is not fast enough to produce a "realistic" or proportionate sound at different levels nor will it successfully "peak-limit". However it will respond to BOTH the LOUD and the SOFT volume levels and attempt to "normalize" them.

AURAL EXCITER: Finally, an exciter is unlike any of the above. Being a completely linear device, it doesn't care the least about dynamics. As a matter of fact its output is ADDED to the original signal, whereas in the above cases the original signal is passed THROUGH the device and is CHANGED. In short, an exciter is used to ENHANCE the original sound. It takes the original sound, produces some sort of "white noise" or "pink noise"(not known due to the patented trade secrets) and modulates one on top of the other. The result is a beautifully defined high-end (800 Hz - 20KHz) without the ugly frequency discoloration you would get from a graphic equalizer. Sounds which are usually "hidden" in the background amazingly just spring to life. As a matter of fact, it can enhance the high-end frequencies on a scale that would be impossible to match with a graphic equalizer! All without adding terrible amounts of actual VOLUME. A great way to protect one's system. If you have imagined that FM can sometimes sound better than your own CD's at times, then you have most likely heard one of these in use at a radio station!!! Buy yourself an exciter and play your own CD's through it. It is also interesting to note (for you musicians out there) that an electric guitar's distortion pedal bears resemblance (in crude theory) to an exciter. It takes a signal, adds modulated distortion to it, and causes it to "sound" much louder than the original sound (without technically getting as loud as it may seem).
-- djchriski, Sep 07 2001


Thanks djchriski. My band uses the aural exciter in the recording process sometimes. The secret of our success, no doubt.
-- snarfyguy, Sep 08 2001


Yeah, thanks [djchriski] nice explainin'
-- lummox, Jan 22 2002



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