If you had to take away one key piece of advice from this article it would be to make sure that your amplifier is configured to output the same wattage as the RMS of the speakers and car subwoofers that it is feeding. Doing so will drastically reduce the chance of your equipment failing, and will give you the peace of mind knowing that your system is working efficiently and can cruise along for long periods of time without any issues.
RMS is an acronym for root mean square, which serves as a precise mathematical way to measure AC signal strength. The term RMS was coined by electrical engineers and has since been adopted in many other disciplines as well including physics, acoustics, climate change research, and many more.
Root mean square is a measurement of how strong an electric current is, with higher RMS power generally meaning more powerful sound. For example, if you were to select two speakers that are being sold and wanted to know which one would give you the most power when it comes to your listening pleasure, then you could use the RMS rating as a key measurement in figuring out which speaker would be better suited for you.
Keep in mind that the RMS power is an electric current calculation, so you will need to know the resistance and length of wiring. You should also subtract any resistors or loads from this equation. To do so, use a formula:. One thing to remember when calculating your average power is that the power goes up exponentially as the number of speakers increases. The RMS wattage is calculated by multiplying the voltage times the current for each speaker. The idea behind an RMS measurement is that most speakers have a variety of power ratings: rated at say 4 ohms, 8 ohms, each of which might be true depending on the frequencies they produce..
An rms rating would show distortion levels of a speaker under specific load conditions and at different power levels. The idea is that the RMS rating would show how it would perform in your home theater or car stereo system, with other components of various impedances.
This is only accurate for a pure and unclipped sine wave. If you do, look for 50 watts at least. More bass does not necessarily mean better bass. The power is determined by the wattage of the subwoofer in question, where a higher wattage demonstrates a more powerful subwoofer.
You can also use a multimeter to measure amperage at the speaker. When working with a sine wave, the RMS value is equal to the Peak value, times 0. A device that uses 10 W of DC will be using the exact same amount of power over time as a device that uses 10 Wrms of AC.
Skip to content. Search for:. Home » QA. 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.
For example, if you need watts continuous power to achieve the desired average SPL, you need 1, watts continuous to handle 10 dB peaks, 3, watts to handle 15 dB peaks, and 10, watts to handle 20 dB peaks. Clearly, the peaks require far more power than the average levels.
In the calculator's Peak Headroom field, enter 6 dB for rock music that is compressed or limited, or enter 20 to 25 dB for uncompressed live music. If you can live with some short-term clipping which may be inaudible, enter 10 to 15 dB. This is the distance from the loudspeaker to the farthest listener. If you are using several loudspeakers that extend into the audience, this distance is from the nearest loudspeaker.
For example, if the audience is feet deep, and you have speakers at 0 feet and 50 feet, the listener distance is 50 feet.
If you don't know this distance, you can make a rough estimate from the typical values below. Be sure to enter the distance in meters m. Coffee house: 16 to 32 feet 4. Listed below are typical sound pressure levels SPLs for various types of music. The SPL meter was set to C-weighting, slow response. You might want your system to be at least 10 dB above the background noise level to achieve a good signal-to-noise ratio.
The calculations discussed here apply to anechoic or outdoor conditions. If the sound system is inside a venue, the room reverberation will increase the SPL typically by 6 dB.
0コメント