Laney Concept Application Notes Schematic

Laney

Concept Loudspeakers

Applications

Concept

Laney

Concept Loudspeakers

Applications

1Cover
2 Contents
3 Introduction + Impedance
4 Hints + Safety
5VocalPA
6 Music + Vocal Pa
7 Full Range Sound Reinforcement
8 Full Range Sound Reinforcement
9 Specifications and Range Information

Concept

Laney

Concept Application Notes

Myths and Reality of Sound Systems

Introduction

Within this application note you will 4 sound systems which fullfill most of all typical system requirements.
The systems which are covered :-

1) Vocal PA

2) Full Range + Vocal PA

3) Full Range Sound Reinforcement

4) Full Range Sound Reinforcement

Before these systems are discussed its worth discussing myths and realities of sound systems.

Speaker Impedance - Do I buy 4 ohm or 8 ohm Enclosures ?

At some point while shopping around to buy your sound system you will be told you need 4 ohm cabinets
because its claimed they are louder .This may be due to what your supplier has in stock or its what a
particular manufacturer recommends - but what is actually true ?

Youcouldlookforamathematicalansweritwillsaychangeyour8ohmloudspeakertoa4ohmloudspeaker
you’ll get double the power. in practice most of amplifiers have conventional power supplies ,when
youdrivean ampwhichwilldo70W@8ohmsitwilldo100W@4ohmsnotdouble the power after all.

Even so I hear you cry that’s still a whole 30W more output from my loudspeaker. Lets have a look at a few
figures

Sound intensity is a logarithmic law so in fact to get twice as loud as your 70W you will need about a 700W
amplifier-bygoingtoa4ohmcabinetanddissipating an extra 30W in the driver you won’t get 30% more
sound level you’ll probably only end up with 10-15% if you are lucky.

What you will do though is increase the working temperature of the voice coil so any fractional increase in
output level you did get would be taken away due to thermal compression which could be as much as a 25%
reduction in sound level..

So by using an 8 ohm enclosure the following happens :

1)Reliability Improved - the working temperature of the Loudspeakers voice coil is decreased

2)Reduced thermal compression - 50% less than in a similar 4 ohm unit

3)A Flexible sound System - you can parallel 2 loudspeakers together

4)If you run your amps at 8 ohms they run cooler - good for long term reliability.

False

So any marginal increase output level achieved by going to 4 ohm cabinets will instantly be taken away from
you in thermal compression and reliability.

Concept

Data