This is an excellent question! A question that most people don't think about until they are offered additional speakers by the Audio Visual provider or until they are having issues with the sound at their event.
These days, most professional speakers are able to get extremely loud, and yes; if you were to put one of these speakers at full blast at one end of an empty hall, you will almost certainly be able to hear it at the other end of the hall.
So then why would any additional speakers be necessary?
1. Coverage and acoustics -
The goal is for everyone in the room to be able to hear, but not to be deafened by the sound.
In order to do that, an AV professional needs to assess the acoustics of the room or the hall and determine how many additional speakers will be necessary, to ensure clarity and a good volume level throughout. More speakers doesn't need to mean more volume - it means better coverage of the room and a better experience for your attendees.
2. Speech intelligibility -
When a presenter is speaking, especially someone who is not an expertly trained public speaker who is used to speaking in front of large crowds; it is very important that the sound engineer has control over finite elements of their voice so that everything they say can be heard clearly. Over long distances, the sound that comes out of a speaker will be affected by the physical parameters of the room and the existing acoustics, thus losing the finesse. For this reason, having more speakers spread out throughout the room is a great help and a great way to ensure that all messages comes across clearly.
3. Control -
Have you ever been to an event where there was a packed dance floor with loud music, and anyone who was sitting at tables around the room trying to have a conversation could not hear anything because the music was so loud?
This is because the main sound system was blasting the music very loudly in all directions, because there were probably speeches earlier in the night that the whole room needed to hear, and since they didn't have enough speakers, they just used their main speakers for the whole event and the system was tuned to just be loud enough that the sound would get all arou do the room.
If additional speakers were added around the room, then the main DJ or band system could have been only focused on the dance floor, and the additional speakers would be used for speeches, background music etc.... And this would allow a packed dance floor with loud music but much quieter areas around the rest of the room.
I recall being at a large event with 7000 attendees (investment conference) and it seemed that the client wanted to save on the cost of sound, because there were only 2 massive, extremely loud and powerful speakers at the very front.
After 10 minutes, some people started leaving and others were complaining that they couldn't hear.
The main speaker got very upset at the event organizer in front of the whole room full of audience and told everyone to take a 1 hour break, and he instructed the audio visual company to fix the sound issue immediately, and only proceeded when and additional 24-30 speakers were set up in the room. Which was the appropriate amount for a room of that size.
Please contact us for a consultation on how many speakers you will need for your next event, and ask us about upgrading to convert grade line array systems for your premium ad large scale events.