Citat:
ackopk: Jel moze neko da postavi neki tekst o AES standardu.
Interesuju me metode merenja???
Pozdrav!
Aleksandar.
POST 5:
BackEMF :AES power handling is perhaps one of the best defined ratings for loudspeakers.
It is simply pink noise filtered between 125Hz and 8kHz with a peak to average ratio of 6dB and applied over a period of two hours. It is one of the better indicators of both the thermal and mechanical aspects of power handling.
post 7:
museav:I believe that RMS power is a misnomer, it has become commonly used but it really is a meaningless value and is actually the calculated power based on RMS voltage and current measurements. Also realize that Program and Peak ratings are calculated rather than measured values, the AES test signal used has a 6dB crest factor, the peaks are 6dB above the average, so the "peak" power is 6dB (4X) the continuous power while "Program" is essentially a made up rating to reflect that the test signal is not the same as a typical program source such as music and it is typically simply 3dB (2X) above the continuous rating.
There are numerous different speaker power rating schemes, some intended for individual drivers and some for full range devices. AES ratings are quite common and you might see IEC/EIA ratings as well. A few manufacturers use their own proprietary hybrid or modifications of some of the standard test methods. Many of the differences relate to the driving signal applied (bandwidth, filter slopes, crest factor, etc.) and the time the signal is applied. There are pros and cons to each method. And do not think that marketing is not a factor in this, how many people really understand or even notice the differences in the test methods or specifics of the ratings versus those that simply look at the numbers? So if your competition changes the test methods used or how the information is reported then from a sales perspective there is definitely some pressure to do the same.
As the specs for gaff's sub show, the length of test is a factor can also be a factor as longer test times can start to reveal long term issues, typically thermal, when the speaker is driven continuously for long periods. Not necessarily applicable for your 2 hour show with live music but perhaps relevant to the all night DJ with heavily compressed source material.
One of the limitations with current power ratings is that a speaker could have a noticeable change in response before reaching the rated power and that would not be identified. There are also a lot of calculated vlaues reported for both speakers and amplifiers. There is a move within AES and by some of the independent speaker testing labs to develop new speaker and amplifier rating systems that are based on the actual voltage and current measurements rather than calculated power levels and that for speakers define the power limit as when an audible (3dB) change occurs in the frequency response. This makes a lot of sense to me as it means you are really looking at when the power starts to affect what is heard and it is also a condition from which most speakers could recover.
"chop your own wood and it will warm you twice..."
Re: Nacrti zvucnih kutija, bas binovi, razlasne kutije...
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