2 speakers per channel probably isn't a problem. You would nned to check the minimum permissable load for the amp.
1/Rp = 1/(1/R1+1/R2+...1/Rn)
R= Parallel combination of n speakers
Rs= R1 + R2 + ... +Rn)
Rs = The series combination of n speakers
Two 8 ohm speakers in parallel is 4 ohms and if I did it right three in parallel would be 2.6 ohms which could be a problem for some amps.
In parallel, the volume should stay about the same, but series combinations will vary the volume.
Timer controlled relays will work fine as long as the AMP can handle it.
We probably could provide more info with more information:
1. wattage of amp
2. Max Listening level (Rms voltage across any given speaker)
3. Minimum load allowed by amplifier
If you had a 1 KW amp stable into a 2 ohm load then not a problem.
If you had a 10 watt amp with an 8 ohm minimum load then a problem.
Of course, the answer lies somewhere between these limits.
You could, however, buy L-pads for each of the speakers. Wire 2 speakers in parallel and place that combination in parallel or series with another speaker so you would then have 4 ohm in parallel with 8 or 8 ohms in series with 4 ohms.
For each speaker, wire a DPDT switch that will select a resistor or speaker for the load. Have thes controlled by timers.
A second AMP.
Just can't evaluate cost-effective options without more information.
Even maximum speaker switches (total) during a day might help help.
1/Rp = 1/(1/R1+1/R2+...1/Rn)
R= Parallel combination of n speakers
Rs= R1 + R2 + ... +Rn)
Rs = The series combination of n speakers
Two 8 ohm speakers in parallel is 4 ohms and if I did it right three in parallel would be 2.6 ohms which could be a problem for some amps.
In parallel, the volume should stay about the same, but series combinations will vary the volume.
Timer controlled relays will work fine as long as the AMP can handle it.
We probably could provide more info with more information:
1. wattage of amp
2. Max Listening level (Rms voltage across any given speaker)
3. Minimum load allowed by amplifier
If you had a 1 KW amp stable into a 2 ohm load then not a problem.
If you had a 10 watt amp with an 8 ohm minimum load then a problem.
Of course, the answer lies somewhere between these limits.
You could, however, buy L-pads for each of the speakers. Wire 2 speakers in parallel and place that combination in parallel or series with another speaker so you would then have 4 ohm in parallel with 8 or 8 ohms in series with 4 ohms.
For each speaker, wire a DPDT switch that will select a resistor or speaker for the load. Have thes controlled by timers.
A second AMP.
Just can't evaluate cost-effective options without more information.
Even maximum speaker switches (total) during a day might help help.
Hi,
a number of solutions.
Wire two sets of the relay controlled speaker in series, giving 16ohm. Then wire in the third pair in parallel to the first two sets.
The worst impedance is 5.3ohms. Care with the series set to avoid both relays going to straight through and shorting out the amp.
Unfortunately, the volumes are not matched.
What about using transformer coupling as in PA work.
2:1 transformers will convert the speaker impedance to an effective 32ohm. Then you can wire as many as four sets in parallel and still stay at 8ohm or above.
2:1 audio transformers that can handle wideband speaker currents will not be cheap retail, but there are bargains out there.
Or is it the timers that you are enquiring about?
a number of solutions.
Wire two sets of the relay controlled speaker in series, giving 16ohm. Then wire in the third pair in parallel to the first two sets.
The worst impedance is 5.3ohms. Care with the series set to avoid both relays going to straight through and shorting out the amp.
Unfortunately, the volumes are not matched.
What about using transformer coupling as in PA work.
2:1 transformers will convert the speaker impedance to an effective 32ohm. Then you can wire as many as four sets in parallel and still stay at 8ohm or above.
2:1 audio transformers that can handle wideband speaker currents will not be cheap retail, but there are bargains out there.
Or is it the timers that you are enquiring about?
Finding the proper timer device is the concern. as it needs to be turned on/off at percise pre-determined times.
The sound system is only to provide audio for plants to listen to so output and sound quality are not a priority, nor is volume matching from room to room.
As well, we may end up running three speakers in total (1 per room) if it makes the wiring easier.
For the record I am not making any claims as to whether or not this will improve the quailty of the plants - I am just trying to help my friend with his project.
The amp will be a Luxman m-113 2ch power amp, I think it was rated around 50w/ch @ 8ohms RMS.
Thanks for the input...
The sound system is only to provide audio for plants to listen to so output and sound quality are not a priority, nor is volume matching from room to room.
As well, we may end up running three speakers in total (1 per room) if it makes the wiring easier.
For the record I am not making any claims as to whether or not this will improve the quailty of the plants - I am just trying to help my friend with his project.
The amp will be a Luxman m-113 2ch power amp, I think it was rated around 50w/ch @ 8ohms RMS.
Thanks for the input...
Hi,
a DIY adjustable timer that is precise and three independent channels and repeatable from day to day will be quite a project.
Those plug in timers intended for table lamps etc, are fairly precise.
Wire two speakers in series on one channel.
Wire the next two series speakers to the second channel. I've heard that plants can't tell if it's not stereo.
Finally wire the last series pair to one or other channel.
Each series pair can be connected at will by a relay.
Now just work on the control.
a DIY adjustable timer that is precise and three independent channels and repeatable from day to day will be quite a project.
Those plug in timers intended for table lamps etc, are fairly precise.
Wire two speakers in series on one channel.
Wire the next two series speakers to the second channel. I've heard that plants can't tell if it's not stereo.
Finally wire the last series pair to one or other channel.
Each series pair can be connected at will by a relay.
Now just work on the control.
Get some 120V timers or X10 relay modules. Cut some traces and isolate the switch (or relay) contacts from 120V. If using the X10 module, use an X10 controller (the one that looks like a digital clock) or a computer with a serial or USB X10 interface to control the modules. X10.com always has some kind of package deal going, or you might find some ex-Radio Shack house brand X10-compatible stuff at a liquidator.
I think there are X10 modules with dry contacts, but they'll be harder to find. And it's the appliance modules that have the relay contacts, not the lamp modules (which are dimmable). Of course, if you have some 120V AC coil relays you could just plug those into either style of X10 module and save some hacking around.
I think there are X10 modules with dry contacts, but they'll be harder to find. And it's the appliance modules that have the relay contacts, not the lamp modules (which are dimmable). Of course, if you have some 120V AC coil relays you could just plug those into either style of X10 module and save some hacking around.
Do it the way everybody else does it. You don't need a full blown PLC, but something like this might do:
http://www.idec.com/Products/ENG/PDF/brochures/FL1C_SmartRelay_2004.pdf
Again, your missing specifications.
Precise: down to the nano second?, Relative to each other?
Same schedule for a day, a week, a month, a year, a century
How easily does it have to be changeable?
How many times a day does it switch: 1 on, 1 off; right?
http://www.idec.com/Products/ENG/PDF/brochures/FL1C_SmartRelay_2004.pdf
Again, your missing specifications.
Precise: down to the nano second?, Relative to each other?
Same schedule for a day, a week, a month, a year, a century
How easily does it have to be changeable?
How many times a day does it switch: 1 on, 1 off; right?
I should know the exact timing sequence in a few days.
It should go something like so:
1am-audio on
2am-lights on
2pm-lights off
3pm-audio off
Then as the growing cycle changes there will be longer light cycles.
Perhaps "percise" was a strong word...more it needs to be consistant and follow the same pattern as the remaining system.
The lights are controlled by a simple 120volt timer like this:
As well there is a C/O2 system that will come on at the same time as the audio (on 1hr before light and off lhr after light). The C/O2 system is currently in place and I believe it is on the same type of timer control as the lighting, this too I will double check when i am next at the greenhouse (tomorrow).
Thanks for the input everyone!
It should go something like so:
1am-audio on
2am-lights on
2pm-lights off
3pm-audio off
Then as the growing cycle changes there will be longer light cycles.
Perhaps "percise" was a strong word...more it needs to be consistant and follow the same pattern as the remaining system.
The lights are controlled by a simple 120volt timer like this:
An externally hosted image should be here but it was not working when we last tested it.
As well there is a C/O2 system that will come on at the same time as the audio (on 1hr before light and off lhr after light). The C/O2 system is currently in place and I believe it is on the same type of timer control as the lighting, this too I will double check when i am next at the greenhouse (tomorrow).
Thanks for the input everyone!
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