Line Source or Point Source Speakers??

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Choosing between Point Source and Line Source speakers can be tricky in the world of high-performance home cinema, but mastering these skills is essential in ensuring each customer gets the right system for them and their space. Creating a high-performance system of any type requires not just the acquisition of knowledge, but the experience of the application of that knowledge across a wide range of situations to ensure the customer is always getting the best result.??

One of the most crucial decisions we make when creating a world-class home cinema is the type of speakers we use for each project. One of the biggest of these decisions to be made within this area is the choice between Point Source or Line Source speakers.??

Point Source Speakers

Point Source would probably be the most familiar to the layman. These are made up of a tweeter and a mid-range driver often contained within a rectangular box and in the world of home cinema they are also often integrated into the wall itself.

Conventional 2-driver bookshelf point source speaker

A true point source speaker with all frequencies emanating from the same point, both the high frequencies and low frequencies originate in the single (Coaxial) dual driver (Point Source)

An in-wall point source speaker

Line Source Speakers

Line Source speakers are a different animal and are made up of a long, usually thinner speaker, where mid drivers and tweeters are placed in vertical rows next to each other within a long rectangular enclosure. These also can be integrated into the wall of the cinema.

An in-wall Line source speaker

Floor-standing Line Source speakers

Both offer great performance when deployed correctly and calibrated to the room but have different characteristics and performance curves that mean the shape and size of the room, the customer's preferences and how the cinema is going to be used. All must be considered before we make our selection.?

A sound decision?

Before we delve deeper, we need to make sure we understand how sound works. The easiest example is to begin with the type of sound most people are familiar with, stereo, where two main speakers and perhaps a subwoofer create a ‘sound stage’ for the listener to enjoy.??

Sound mixers, when working with a stereo signal will place the sounds inside the mix to replicate a band on stage. The vocals will be in the middle of the stage, the lead guitar say to the right, the drums just behind the singer and the bass say off to the left. If the speakers are placed correctly and are at the same volume at all frequencies, the ‘sound stage’ (the apparent depth, height, and width of the audio) reaches the listener from its two separate delivery points at exactly the same time and same volume. This means that the arrangements within the mix the engineer created will be reproduced perfectly, producing the correct ‘imaging’ (the perception of where the different instruments are within the sound stage).?

A visual representation of an audio recording where a listener can hear the positions of all the band members

If the speakers are ‘off’ in terms of volume or placement with one being slightly closer to the listening position, the ‘imaging’ produced by the system will be affected and not deliver what the artist and mixer had intended. Sounds will move around within the sound stage and not be where they should be. This is because sound waves arrive at the incorrect volume or time at the listener. They get quieter, the further away they are and will arrive at a different time losing the image focus and staging.?

In order to get good imaging and staging we must also manage reflections from walls and other surfaces as well as the right sounds arriving at the right volume and time?

A good stereo reproduction is hard enough, now imagine what is involved with many speakers and many seating positions as you typically get in a Home Cinema It’s a serious challenge.?

Making the right choice?

Understanding how sound behaves is fundamental in making this choice. Sound volume lessens as it travels away from a point source speaker at a rate of 6b for every time you double the distance between the speakers and the listening position. If you take a conventional point source speaker that has a sensitivity (loudness) of 90db at one metre from the speaker cone, that means by the time the sound reaches two metres from the speaker it has dropped to 84db, at four metres it will be 78db and by the time it gets to eight metres it is 72db.

This represents a big drop in volume from the front of the cinema and one that customers will definitely notice because as a rule of thumb, if a signal drops by only 10db, the human ear perceives that as the volume halving from what it was originally.??The rear of the room could be as much as minus 18db!! If the room is 8mts long.

Line Array speakers offer an alternative solution as sound behaves differently from this type of speaker. Using the same calculation as for point source, a Line Array speaker will only lose 3db for each time you double the distance between the travelling sound wave and the speaker

Using Line Source speakers improves this decay dramatically, now over an 8m deep room, the drop is only 9db instead of 18db.

Most of the really important information in a home cinema comes from the front speakers, so we need to ensure that the audio spreads across the whole of the room without these perceptible drops in volume and this is even before you have considered the behaviour of the surround speakers. The key to all of this is balance.??

The different characteristics of these speaker types mean that Point Source is usually better for smaller spaces and is a good choice when the customer wants to listen to high-quality music reproduction as well as movies as the imaging tends to be better with Point Source. Line Array are more suited to larger spaces, with multiple rows of seats and for the cinema purist who is less likely to want their system to play back other types of content like Hi Fidelity music.?

There are many other characteristics to keep in mind as well. Here we have just touched on the very basics of what we consider when choosing your equipment when building a home cinema.??

As always for the very best results, if you are looking to enjoy a high-performance home cinema, work with an expert.

Prestige Audio UK is only a phone call away.

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