Speakers in series/parallel: is this proposed setup safe and reliable ?

[Steeveax]

Hi, am new to forum, hope I'll be accepted by your team...Please anybody could help...
Be free to rectify my setup if wrong.
Wish to install in small hall 15 x 15 meters x 3H: 2 channel of 9 speakers each (8Ω - 50 watts each) in series/parallel with Resultant Impedance 8Ω (8Ω x 3sp = 24 / 3 = 8Ω) per channel, the max continuous demand output per speaker is 10 watts with 15 ± watts PEAK from time to time, depends on speech rates (NO crying). Would like to know the following:-
What will be the type/power of amplifier output ?
What size of wire from amplifier to one group of speakers when the length required is 24 meters to a channel ?
What will be the major problem in this ser/para wiring system ?

SPEAKER:- 8ohms 50watts but volume needed is 15 watts
NO Woofer or Sub woofer - Just midrange/ medium
Bass control will set at lesser
Treble control will set at haft
Speakers mounting height 2.5 meters from floor.
AMPLIFIER CHOICE: is it useless to use a HI-Fi amplifier for this system ?

 

[TLS Guy]

Hi, am new to forum, hope I'll be accepted by your team...Please anybody could help...
Be free to rectify my setup if wrong.
Wish to install in small hall 15 x 15 meters x 3H: 2 channel of 9 speakers each (8Ω - 50 watts each) in series/parallel with Resultant Impedance 8Ω (8Ω x 3sp = 24 / 3 = 8Ω) per channel, the max continuous demand output per speaker is 10 watts with 15 ± watts PEAK from time to time, depends on speech rates (NO crying). Would like to know the following:-
What will be the type/power of amplifier output ?
What size of wire from amplifier to one group of speakers when the length required is 24 meters to a channel ?
What will be the major problem in this ser/para wiring system ?

SPEAKER:- 8ohms 50watts but volume needed is 15 watts
NO Woofer or Sub woofer - Just midrange/ medium
Bass control will set at lesser
Treble control will set at haft
Speakers mounting height 2.5 meters from floor.
AMPLIFIER CHOICE: is it useless to use a HI-Fi amplifier for this system ?

I would not use two channel for this, I would use mono. You can not series parallel an odd number of speakers. Your best solution is to use a PA amp with 70 volt output. There is a tap on each speaker in a 70 volt system marked in watts. You can adjust the power to an individual speaker any way you want. The rule is that the sum of the individual power taps, must equal the maximum power available from the amplifier. That way the impedance is correct. So search for 70 volt PA amps of the power you need and then search ceiling speakers for 70 volt systems. You can use small gauge bell wire to hook up the speakers in a 70 volt systems, as the current is very low.

 

[Speedskater]

For a sitution like this a 70 Volt (or 25V, 100V) set-up is the way to go.

From Rane Corp.

Constant-Voltage Audio Distribution Systems:
25, 70.7 & 100 Volts

http://www.rane.com/pdf/ranenotes/Constant_Voltage_Audio_Distribution_Systems.pdf

 

[lsiberian]

I suggest getting professional help. If you don't know what you are doing then you shouldn't be doing it in a professional setting there is too much liability risk.

 

[j_garcia]

Besides what TLS has suggested, maybe an impedance matching speaker selector/distribution hub would work?