What is intelligibility? The state or quality of being understood. It can apply to an idea or a writing, but in our context it relates to the spoken word and, less commonly, to music Choosing loudspeaker cable The importance of cables for the connection between the amplifier and the speaker is often controversial.
Hi-fi aficionados spend fortunes on cables that promise spectacular results, and our short auditory memory and subjectivity lead many to confirm these improvements in their systems Constant voltage systems 70V, V lines Constant voltage, high impedance or line transformer systems are often a somewhat confusing concept for professionals used to rock and roll.
They are actually very simple to design, among other things because they are intended to be installed by electricians and the like, with little experience in sound systems. In this article we will try to clarify the simple concepts needed to understand this type of system Nowadays, it holds no real meaning. This form of power rating refers to the maximum amount of power the speaker can handle in an instant without damage.
We do not recommend that you use the peak, max, PMPO or dynamic power rating when configuring your system because it does not reflect the products capability under everyday use.
Manufacturers still advertise peak power because most consumers are unaware of its meaning. Peak power is used to make a product seem more powerful than it actually is, sometimes even four, five or six times more powerful than the RMS rating. Please ignore Peak Power Ratings. The crest factor corresponds to how high the peaks are above the average level. The average level is measured by an RMS voltage meter and this is called the continuous level. The crest factor is typically 6dB, which means the peaks in the pink noise are twice the voltage level of the continuous RMS measurement.
If you double the voltage at the peaks, it creates four times the wattage, because the voltage is squared. The program level is just a reference where the wattage has doubled and is not really a testing parameter.
The continuous rating is the base line wattage that the cabinet can handle without risking any harm to the voice coil or other parts of the speaker. This is considering extended periods of use, like at a gig or rehearsal. The speaker can handle peaks of four times, but these are short clean audio peaks, not the continuous output of clipping. Using amplifiers that are under the continuous rating will not harm your speaker. Under powering a speaker will not bring the speaker to full output.
On the other hand, you can under power a show by bringing too small a system for the show and running it into clipping. The program rating is the maximum wattage that the speaker can handle in bursts. This is usually the better amplifier wattage to shoot for when matching an amp to a speaker.
The PM12 has a program ratting of W. If you use a W amplifier you have 3dB more of clean headroom before approaching clipping. Also, amplifiers are limited in their power supplies and usually only produce about twice more output on peaks, so this could produce the full W peaks. Or at least that is in theory. This would then produce the full output of the speaker or Max SPL.
The peak rating is the maximum wattage the voice coils can take in very short peaks. If you use much more power, you are likely to damage the speaker by forcing the speaker cone to its limits. If you use much less power, youll probably turn up the amp until it clips, trying to make the speaker loud enough. Clipping can damage speakers due to overheating. So stay with 1. This section will suggest how big a power amplifier you need to fill a venue with loud, clear sound.
Basically, the louder the sound system and the bigger the room, the more power is required. Loudspeakers with high sensitivity need less power than loudspeakers with low sensitivity. The list below recommends the total amplifier power needed for several applications. Each application has a range of power based on the desired loudness and the typical loudspeaker sensitivity. Although a rock concert in an arena could be powered by 15, watts allowing only 6 dB of headroom for peaks, you'll often see large touring sound companies using 80, to , watts total.
That much power is needed to handle to dB peaks without any clipping, and to power extra speakers for even coverage of a large area. If one loudspeaker won't handle the total power required, you need to divide the total power among multiple loudspeakers and multiple amplifier channels.
For example, suppose you need watts to achieve the desired average loudness, but your speakers power handling is watts continuous.
You could use a power amplifier of watts per channel. Connect two loudspeakers in parallel on each channel. That way, each speaker will receive watts not considering the change in amplifier power at different impedances, and not considering cable losses.
Note that if you parallel two speakers, their total impedance is halved. For example, two 8-ohm speakers in parallel have an impedance of 4 ohms. In that case, each speaker would receive half of the amplifier's 4-ohm power. On the Crown website is a calculator that determines the amplifier power required to achieve the desired SPL at a certain distance. It also accounts for the number of dB of amplifier headroom needed for audio peaks. Text accompanying the calculator gives the equations used.
Click on the following link to go to Crown's power calculator: Calculator. To use that calculator, you need to know the loudspeaker sensitivity, peak headroom, listener distance, and the desired SPL.
Let's examine each factor. The sensitivity spec can be found in the loudspeaker's data sheet. Bigger speakers generally have higher sensitivity than smaller speakers, and high-frequency drivers have higher sensitivity than low-frequency drivers. Because music has transient peaks that are 6 to 25 dB above the average level, the power amplifier needs to produce enough power to handle those peaks without distortion.
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