Double 15, is 2 15-inch speakers, at a glance, large speakers can be seen.
Double 15-inch speakers, a lot of power, generally 500W or more. It is the square to open the concert use of the speaker. 15-inch speakers are stage speakers, singing speakers, midrange is good, bass is not good, only suitable for stage singing, not suitable for home use, because the bass effect is not good, listening to DJ music, watching movies, the bass is not shocking.
Audio refers to other sounds besides human language and music, including the sound of the natural environment, the sound of animals, the sound of machines and tools, and the various sounds emitted by human action.
Audio probably includes amplifiers, peripherals (including pressure limiters, effects, equalizers, VCDs, DVDs, etc.), speakers (speakers, horns), mixing consoles, microphones, display devices and so on add up to a set.
Which, the speaker is the sound output devices, speakers, subwoofer, etc.. A speaker includes high, low and medium speakers, three but not necessarily three. The history of the development of technology can be divided into four stages: electron tubes, transistors, integrated circuits, field effect tubes.
Many live sound mixers do not pay attention to the relationship between audio and wavelength, which is actually very important: audio and wavelength are directly related to the speed of sound. At altitude air pressure, at 21 degrees Celsius, the speed of sound is 344m/s, and I've been in contact with tuners in China who commonly use a speed of 34Om/s, which is the speed of sound at 15 degrees Celsius.
But the main thing to remember is that the speed of the sound will change with the air temperature and air pressure, the lower the temperature, the density of molecules in the air will increase, so the speed of the sound will decrease, and if you do the live sound at high altitude, because of the reduction of air pressure, the molecules in the air become rare, the speed of the sound will increase.
The relationship between audio and wavelength and sound is: wavelength=sound speed/frequency; λ=v/f, if you assume that the speed of sound is 344 m/s when the wavelength of 100Hz audio is 3.44 m, 1000hz (i.e., lkHz) wavelength is 34.4 cm, and a 20kHz audio wavelength of 1.7 cm.