One of the vital element in film, live concerts, press release, radio, and many more is having a good audio quality. While it is true that having a good visual can captivate your audience easily but accompanying it with bad audio can quickly turn them off, so sound systems should be listed as priority of any directors and producers and picking up the right microphone for an event or in filmmaking could help you build a better overall sound quality.

Microphone Pickup Patterns

To start up, we should be inform that not every microphones are created equal though their functions are all similar to one another and it is for example taking the physical sound and translate it into electrical signal that we can control. Microphones function are differs from their pickup pattern or the direction on which mic pick ups sound, knowing this will help you on which mic is suitable for your use in an event or filmmaking and could avoid unnecessary noise and feedback which could distract your audience. So without further ado, let’s start discussing different types of pickup pattern.

Omnidirectional

It is quite common pickup pattern for a microphone. Omnidirectional mic can picks up sound 360° around the mic with equal gain in all angles, this means that the sound source is not necessarily needed to be directly at front of the Mic just to be heard. Though its disadvantage is that you can also easily picks up the ambient sound or even having a feedback, but if you want to capture both the primary sound and ambient noise, using this type of mic is a good choice to make

Advantage:

• Can pickup sound at all direction.
• Good at interviews where guest can move their heads freely when expressing their emotions.
• Less sensitive to plosives.

Disadvantage:

• Can also capture ambient sound.
• Often feedback.

Cardioid

Cardioid pattern get its name because of its distinct heart shape. As you can see from above diagram, cardioid mic can picks up sound at its front and very least from the back. It has also has wide pick up range or angle which mostly 131°, this can be use by singers who uses same mic and another noticeable feature is its feedback rejection.

Advantage:

• Wide range of pick up angle.
• Feedback rejection.

Disadvantage:

• Can suffer from proximity effect and plosives or popping sound.

Supercardioid

One of the subcategory of cardioid microphones and basically has overall same feature with the difference of having more side rejection than typical cardioid. It also has a distinct feature of ability to isolate the polar area for unwanted noise, this will help you to reduce the ambient noise and the feedback greatly.

Advantage:

• Greatly reduce noise and feedback.

Disadvantage:

• The sound source must remain at the front of the mic, and little move of the head might result to significant reduce of volume.

Hypercardioid

It has both share similarities in supercardioids and bidirectional microphones. Hypercardioids are effective at rejecting sounds and feedback from the sides.

Advantage:

• Rejects feedback and unwanted noise from the sides.
• Can pick up more sound at the back compare to cardioid and supercardioid.

Disadvantage:

• Sound source must remain at the front of the mic.
• Not ideal for speeches and interviews.

Bidirectional or Figure-8

Bidirectional or figure-8 microphones can picks up sound at front and back of the mic and rejects any noise that comes from the side. The pattern is similar to a two cardioid but facing opposite to each other. This pickup pattern is commonly use at duets which gives two performers space while sharing the same mic. We can also use this on interviews where the interviewee and interviewer are facing at the opposite side facing on the same mic and both are heard with equal sound by the audience.

Advantage:

• Can be use in stage performance such as duet, where two performers are needed to share a mic for showing intimacy.
• Can be use in talk show or interviews on which you can only use one mic.
• Rejects noise at sides.

Disadvantage:

• Cannot be use in large number of performers.
• Could picks up noise at the back when you only need the front.

Lobar Pickup or Shotgun

The most directional pickup pattern, lobar microphones has a ultra-narrow pick-up angle which makes it hard to use and not a popular choice for studio. It must point at high precision because a little move of the source could result for that sound to loss. But the advantage of this microphone compare to others is that it greatly rejects both the noise and feedback from most of the direction except from the direction where it is sensitive like its front.

Some shotgun mics has a sensitivity at sides, but it is rather less comparing to its front and rear and also very narrow. The rear also has very narrow pick up and much less sensitive compare to front.

Advantage:

• Have the best noise and feedback rejection among other types.
• Good use at filmmaking where it can be mounted in a boom pole.
• Picks up sound at great distance.

Disadvantage:

• Cannot be use in studio.
• Has very narrow pick up angle.

For some people around, amplifiers are all alike, they are just metal box which work was to make your speaker produce sound. But, is it that true? Are all amplifiers the same and can work with all speakers around to produce sound? Well obviously the answer is no, and if you do mindlessly pair amplifiers and speakers then the result is quite.., not good for sure.

So how do we pair our speaker and amplifier? What are the things we need to check to ensure those equipment will last long and would produce desirable sound?

Three Things That You Need To Know

Basically, there are only three things that you need to ensure in pairing your amplifier and speaker, and those things are the impedance, power, and sensitivity. So what are those things? To answer that let’s have little review.

Impedance

Impedance is a electrical resistance of your component, usually, you can find this number with the Ω symbol beside it, indicating that the number is the measure of resistance represented in ohms. We can just check the specs sheet provided by the manufacturer to know the impedance of either amplifier and speaker.

So why is it important? It is important to know for us to be certain that your speaker is compatible to the amplifier, vice versa. The focal point of this is that, it is much safer to connect speaker with high impedance (let’s say 8 ohms) to amplifier that capable of operating with a lower impedance (4 ohms or 6 ohms). What you should not do is to connect amplifier working on high impedance to speaker with lower impedance because it might result to overheating your amplifier.

Power

Power is a rate at which electical energy is converted to other forms of energy such as kinetic, heat, electromagnetic, etc, and expressed as wattage (W). Wattage in speakers means how much power it can handle. On the otherhand, wattage in amplifiers means how much power it produce or putting out.

Most of the specs sheets provides references for both Continuous Power and Dynamic Power. Continuous Power signifies measure of power that your speaker can handle or your amplifier can output in normal operation. On the otherhand, Dynamic Power is the peak power that your speaker can handle or amplifier can produce.

In pairing your amplifier and speaker, you must pay attention to Continuous Power or wattage your amplifier is putting out in normal operation and stack them up against the recommended power that your speaker can handle for safety, and remember, too much power-feed to your speaker can also burn the voice coil, thus damaging your speaker.

Sensitivity

Sensitivity is another factor to remember in pairing your speaker and amplifier, though this thing focuses much more to speakers rather than amplifiers because sensitivity is the measure of loudness your speaker produce in 1 meter per 1 watt. For example, if your speaker sensitivity rated (89dB/1m) it means that it produces loudness of 89dB in 1 meter with 1 watt of input. I guess most of you are baffled as to why we needed more power for supplying our speaker if 1 watt is sufficient to produce loudness of 89dB in 1 meter? Well, techinically if you want to add 3dB of loudness you needed twice the power it originally needed, for example, if have original loudness of 89dB per 1 watt, you need 2 watts to increase it to 92dB, 4 watts to increase it to 95dB, 8 watts to increase it to 98dB and so on and so forth. You also need to remember that per doubling the distance the loudness is reduce by 6dB, so if your speaker has a sensitivity of 89dB in 1 meter, in 2 meters loudness will reduce to 83dB, in 4 meters loudness reduces to 77dB, etc.

The first thing that you need to remember before choosing a speaker are the size of the venue and boundaries that your speaker will interact with such as walls, ceiling, and the floor.

You also need to account your budget and if you want to find best speakers within what you can afford, you should determine what sounds best according to that price tag. So what are the things you need to consider before buying speakers?

First things first, before buying a speaker you must ask for the specification sheet which readily available to most of the reputable manufacturer.

The most important thing to know about speaker specs are the frequency response, sensitivity or sound pressure level (SPL) output, and if you are planning to use passive speaker you should also account the wattage and impedance (ohm resistance).

So what is frequency response? If we look at the sample picture above you would see a frequency response that ranges from 38Hz up to 20kHz, it does mean that the speaker is fine at wide range of musical genre such as country, folk, metal, rock, pop, hip-hop, and classical. To know what is the meaning of lower and higher frequency level (Hz) just look at the picture below.

The sensitivity or the SPL on the other hand determines how loud the speaker at a given distance which typically starts at 1 meter and would decrease by 6dB after doubling the distance. Let’s take the sensitivity of the sample specs above which is 99dB/1m, this would mean that the loudness of the speaker at 1 meter is 99dB, doubling that distance (now 2 meters) the loudness will decrease at 93dB and doubling that distance again (now 4 meters) and the loudness will decrease to 87dB, so on and so forth.

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Just a little bit of trivia, human ear can suffer irritation at above 90dB and would cause irreversible damage at around 120dB higher and in 150dB eardrums could burst. You should also account this whenever you are setting up your sound system as we would not like to damage any ears. You can also buy SPL meters to accurately check how loud your speaker output is.

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Now if you are planning to use passive speaker over active speaker first you also need to know the wattage and impedance your passive speaker had. By the way, passive speakers are speakers that need an external amplifiers to operate, and active speakers are speakers that have built-in amplifiers.

Wattage is the power needed to operate your passive speaker, so taking the wattage of speaker from sample specs above, you would see the “100W(cont)/400W(peak)” this would mean that the continous wattage that the speaker need is 100W with the peak 400W, supply power above this and it could damage or blow up your speaker otherwise your speaker is design to absorb more power than it suggest it might survive and obviously we would want to avoid damaging our speaker as we don’t buy speaker just to blow them up so we need to add to our calculations the power that the speaker can handle to avoid mishaps.

Impedance is a resistance that your speaker offers to the current supplied from amplifier. It is quite tricky and complicated but this is the simple analogy on it, a speaker with lower impedance let’s say 4 ohms would produce louder sound than 8 ohms speaker at the same volume setting. But that doesn’t mean that it is best to buy 4 ohms than 8 ohms speaker because if your amplifier aren’t designed to supply power to 4 ohms speaker it could place a damage to your amplifier because it means that your amplifier needs to supply more power to 4 ohms speaker than 8 ohms which could mean placing a little burden to our friend. On the above spec sheet (again) we see the nominal impedance of “8 ohms Compatible” which means it has a resistance of 8 ohms so you need to raise your volume setting a little bit than normal to produce louder sound.

Another thing to remember in choosing your speaker is identifying the dispersion. Dispersion is the way how your speaker projected the sound vertically and horizontally so it is necessary to know especially in placing speakers to your venue. The specification sheet above doesn’t state any dispersion thing (sadly its quite useless now). So we are using different example, let’s say our speaker has 60° dispersion horizontally and 40° dispersion vertically.

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This data will help you to identify where to face your speaker and the proper height on placing them.