Let us begin by understanding the two major speaker categories.
All speakers, regardless of their characteristics fall into two categories. Active or passive speakers. They are classified thus regarding their relationship with the amplifier driving them. The PA speakers fall in the active speaker category.
For the passive speakers, they have the amplifier as a separate component from the speakers while the active speakers have inbuilt amplifiers.
These two characteristics make it difficult on deciding which of the two to use. Well, each speaker type has its own pros and cons.
Active speakers are ideal where there will be no scalability required. This is because all components are housed in one enclosure, and thus it will be easier to move and setup. However, they are not ideal in situations where scalability is being considered e.g. bands. Also if one component blows, then the entire lot has to go away for repair. There is a number of retailers who sell active speakers around Melbourne and some of them provide excellent goodies with them. For example, Jd’s PA speakers are renowned for excellent after purchase service and comprehensive guarantee.
For the passive speakers, they are quite cumbersome to handle. By using an external amplifier, it means you will require speaker cables to connect the amp to the speakers. Beyond that, you might require crossovers to separate sounds. The high frequency sounds directed to the tweeter while the low-frequency ones are directed to the woofer.
Moreover, they are cumbersome to transport and setup since they have multiple components.
Despite their many cons, their pros are equally as many. For starters, they are more scalable. You can increase the number of speakers and amplifiers as your demand grows. With the many separate components, you can also upgrade your system gradually by upgrading the different components separately. Lastly, it is way easier to troubleshoot, make adjustments and carry out maintenance during a gig since the amplifiers are near you.
Having described the difference between active and passive speakers, what other aspects should you consider before purchasing?
Sensitivity rating refers to how much power a speaker converts into sound. In any sound system, the amplifier sends power to the speaker. The speaker then converts the power into sound. Ideally, all the power should be converted into sound, but a part is lost in the form of heat.
Sensitivity is measured in decibels (dB). The standard method used is placing a microphone connected to a sound level meter in front of a speaker. 1 watt of power is sent to the speaker, and the noise produced measured.
For a more efficient speaker, less power is wasted, and thus its rating will be higher. However, for an inefficient speaker more power is wasted and thus its rating will be higher.
Take a 90dB speaker and an 87dB speaker. The difference in rating is only 3dB, and most might consider it insignificant. However, this difference can mean a whole world of difference in terms of sound. An 87dB speaker will require more power to achieve the same volume as a90db speaker.
Changing your speakers from 87dB to 90dB could be the same as increasing the power from your amplifier. A speaker with a 90dB sensitivity rating is considered excellent.
This is the resistance of current flowing from the amplifier to the speakers and is converted into sound. It is measured in ohms.
Low impedance encourages high current flow while a high impedance only allows a limited current flow.
So the question begs, which one to purchase?
One that fits and is optimum for your amplifier. A low impedance speaker demands more current flow and thus strains your amplifiers while a low impedance speaker will underutilise your amplifier.
Speakers with a 6-8 ohms impedance level are excellent and play safely to enjoyable levels.
3. Frequency response
Frequency response is how a device responds to sound across a range of frequencies measured in hertz. The range is plotted on the x-axis while the sound pressure level which is measured in decibels (dB) is plotted on the y-axis. The sound pressure level shows the maximum variation in volume level and how well a device remains uniform from the lowest to the highest tones.
It is scientifically proven that the human ear can pick up sounds of between 20 Hz to 20 kHz. Take a speaker with a 35 Hz-20 kHz. This means it can achieve a bass as low as 20 Hz and a maximum treble of 20 kHz. Always ensure that the frequency response is followed by -/+x dB. This shows that the speakers are genuine.
4. Signal to noise ratio.
This ratio compares a level of signal power versus a level of noise power. In most equipment, speakers included there is ever a noise floor. The noise floor is the sounds that will always exist in equipment. Could be the humming of a refrigerator, but no matter the case, it will always be there. The noise is a result of running components within the equipment i.e. speaker.
The ratio is measured in decibels (dB). The higher the ratio, the better the speaker. A higher ratio means more useful information is produced than unwanted data (noise).
5. Rooms and acoustics
For most speakers, there is no one size fits all. Different speakers have different room specifications. Different speakers will work better in different spaces. Small speakers might be ideal for the regular size bedroom but might sound faint in a living room. Room size and content can also affect the audio quality. E.g. large cushions, carpets, and pillows will absorb sound.
Therefore, before investing in speakers know the room to place it in and the acoustics within the room. This way, you get the best fit for your house.
6. Getting the right components
For optimum results, speakers ought to be matched with the right amplifier or receiver. The cables should be in good conditions and so should the sound source.
As you can see investing in speakers has more than meets the eye. It requires a bit of dedication into searching for the best speakers that meet your needs. However, with the above checklist, you can rest assured that what you purchase will be nothing short of perfect.