What does the term "dynamic compression" mean when used in reference to audio speakers ?

Actually, the question was...what does it mean in reference to SPEAKERS folks! Audio compression is different and has nothing to do with the speakers. You can have a system with dynamic compression in the audio due to either an actual limiter circuit or not enough amplifier power...but you may have speakers that are not dynamically compressing (just compressed sound).

When a speaker dynamically compresses, it in essence runs out of output capability. This normally happens when a speaker reaches the limits of output and simply can't put out any more sound. It happens often with most inexpensive to medium priced speaker systems (a lot on the "satellite subwoofer systems, particularly the Bose systems). You'll usually run itto it on home theater sound tracks which tend to have a LOT of dynamic range. You will be listening to a sound track at a reference volume and a large transient peak will come along. The speaker system simply runs out of the ability to go any louder (assuming the amplifier still has the headroom and doesn't clip first). Here is an example...say you have a typical satellite/subwoofer speaker system. You are sitting 10 feet from the speakers and you are playing a movie at 90 db at your seats...which means your speakers have to put out 100 db of sound. Now, a 10 db peak comes along (big explosion in the movie...etc). Your speakers need to output 110 db...but they are only capable of 105db. There...you now have dynamic compression. You can also get dynamic compression when there are frequencies that come thru that your system can't reproduce. Take a specific example...somebody has a Bose Acoustimess system (sorry). The bass cube in that system is -3db at 43 hz. Now, you play War of the Worlds on DVD, the section where the machine comes out of the ground which has bass frequencies all the way down into the 10 hz range at high levels. Your bass cube simply cannot reproduce those frequencies with any volume or impact and they simply run out of output (which is why the Acoustimess bass module is NOT a subwoofer). That is another form of dynamic compression. Heres your link Dynamic compression simply means that it is compressing the dynamic range of the sound track....yes....bad definition.