Hi,
I have a sound installation where I will put 24 speakers in a sculpture.
I have a question that might be very simple to all of you regarding power.. a help would be kind as it's not my field.
I will use some Dayton exciters 8ohm / 25W with an amp that is 2x50W @4ohm powered with 18V.
I did a test with 2 speakers and it works well.
But I need 10 speakers so I will use 5 of those little amps.
I will use also 6 x 3W/4ohm speakers with small 2x3W amps that are powered by 5V.
so that's 5 18V powerblacks and 3 5v powerblocks.
I thought I could reduce that and power things in serie.. I asked chat gpt and it said I need for the 18v amps a 40Amp powerblock 😛
First that scared me a little bit thinking it's a lot. But also there's no powerblock doing this.
So how do I calculate the current I need ? because the amp info only says "wide working voltage range of DC4.5-26 V."
I would say for one amp the process is this ? :
2x50 = 100W
P=UI
so I = 100/18 = 5.5A ?
is that right ? I feel 5.5A looks high but what do I know ?
thanks for your advice,
Cheers,
Sylvain
I have a sound installation where I will put 24 speakers in a sculpture.
I have a question that might be very simple to all of you regarding power.. a help would be kind as it's not my field.
I will use some Dayton exciters 8ohm / 25W with an amp that is 2x50W @4ohm powered with 18V.
I did a test with 2 speakers and it works well.
But I need 10 speakers so I will use 5 of those little amps.
I will use also 6 x 3W/4ohm speakers with small 2x3W amps that are powered by 5V.
so that's 5 18V powerblacks and 3 5v powerblocks.
I thought I could reduce that and power things in serie.. I asked chat gpt and it said I need for the 18v amps a 40Amp powerblock 😛
First that scared me a little bit thinking it's a lot. But also there's no powerblock doing this.
So how do I calculate the current I need ? because the amp info only says "wide working voltage range of DC4.5-26 V."
I would say for one amp the process is this ? :
2x50 = 100W
P=UI
so I = 100/18 = 5.5A ?
is that right ? I feel 5.5A looks high but what do I know ?
thanks for your advice,
Cheers,
Sylvain
Just found a wonderfull video explaining this. Actually.. calculations are right but that's 18V not 220 😀
so the actuall current drawn from main is 100W (if I even get there) /220 = 450mA
right ?
so the actuall current drawn from main is 100W (if I even get there) /220 = 450mA
right ?
How loud do you need it? Uses series parallel connections to share a single amp to 4x4 or 3x3 or 2x2 arrays. If you aren't using multichannel effects it can be much simpler.
Share a little more if what you want it to do.
Share a little more if what you want it to do.
Do you want it to work outdoors and be audible from a large distance or inside in a quiet room? In the latter case, your amplifier power is probably much more than you need.
No it will always be indoor and it's a proximity experience. It will be in a large cathedral (expect to be calm) or art museums and galleries.
3 people max passing through a portal covered with these small speakers.
We expect people to get an overall sensation of little sounds coming from everywhere or to get as close as 40cm to listen to one specific speaker.
3 people max passing through a portal covered with these small speakers.
We expect people to get an overall sensation of little sounds coming from everywhere or to get as close as 40cm to listen to one specific speaker.
Starting at 4 ohms is most the problem.
4 ohm speakers dont " make" more power they " use" more power for same voltage.
Basic ohms law. Not really big deal in this circumstance just noted for future reference.
Since required SPL is not that loud 8 ohm drivers with high sensitivity will go much farther.
But 4 ohms likely be fine since each one wont need more than 1 watt the thermal limit is 3 watts for the speakers.
Not like your at max power for the install sound levels.
For just basic distribution if multiple speakers share the same channel/ signal source , you can wire series parallel
Your using 18 volts and 5 volts, actual amplifier output power or voltage is limited on such low voltages.
Plenty of basic high current switch modes that will power this.
Being 5 volt and 12 volt switching supplies are extremely common for LED lights.
Otherwise 5 amp 24 volt " laptop" power supplies are pretty common too.
So a basic open frame 300 watt 5 volt switch mode is not more than 20 bucks.
That will power all your 5 volt amps.
And basic 4 to 5 amp 24 volt laptop power supplies will power your other amplifier modules.
Or a 50 watt amplifier will be fine on a common 96 watt laptop supply 4 or 5 amps.
They also have typical " 250" watt laptop 24 volt supplies 8 or 10 amps.
But one buy 2, don't matter they shouldn't be more than 19 to 25 dollars for laptop supplies.
And no you wont be blasting full 50 watts of power for the install.
4 ohm speakers dont " make" more power they " use" more power for same voltage.
Basic ohms law. Not really big deal in this circumstance just noted for future reference.
Since required SPL is not that loud 8 ohm drivers with high sensitivity will go much farther.
But 4 ohms likely be fine since each one wont need more than 1 watt the thermal limit is 3 watts for the speakers.
Not like your at max power for the install sound levels.
For just basic distribution if multiple speakers share the same channel/ signal source , you can wire series parallel
Your using 18 volts and 5 volts, actual amplifier output power or voltage is limited on such low voltages.
Plenty of basic high current switch modes that will power this.
Being 5 volt and 12 volt switching supplies are extremely common for LED lights.
Otherwise 5 amp 24 volt " laptop" power supplies are pretty common too.
So a basic open frame 300 watt 5 volt switch mode is not more than 20 bucks.
That will power all your 5 volt amps.
And basic 4 to 5 amp 24 volt laptop power supplies will power your other amplifier modules.
Or a 50 watt amplifier will be fine on a common 96 watt laptop supply 4 or 5 amps.
They also have typical " 250" watt laptop 24 volt supplies 8 or 10 amps.
But one buy 2, don't matter they shouldn't be more than 19 to 25 dollars for laptop supplies.
And no you wont be blasting full 50 watts of power for the install.
Hi,
Thank you so much for your answer. Not sure I get all right so would you mind if I send below the link to material I found see if that's a match what you are saying ?
For each of the 2X50 amps I will buy this universal 90W 19.5V 4.6A charger with extra tips and buy some mount case DC sockets 30V 5A so the amp boards are screwed in a plastic case and cable not moving around.
For the 5v amps I found this 300W 5V 60A switch. it's more then the 20"bucks" you describe but maybe it's different currency. But i'm concerned about the quality as some worst review says it's either noisy or failing after a while.
If I go for this I guess I only need a power cord to connect to the G/N/L and then have 3 x 5V outputs I can wire to the pcb board.
Or alternatively I can get 3 independent power blocks like this for these 3 amps... there will be no fan and whould work (?)
thanks again 😉
Thank you so much for your answer. Not sure I get all right so would you mind if I send below the link to material I found see if that's a match what you are saying ?
For each of the 2X50 amps I will buy this universal 90W 19.5V 4.6A charger with extra tips and buy some mount case DC sockets 30V 5A so the amp boards are screwed in a plastic case and cable not moving around.
For the 5v amps I found this 300W 5V 60A switch. it's more then the 20"bucks" you describe but maybe it's different currency. But i'm concerned about the quality as some worst review says it's either noisy or failing after a while.
If I go for this I guess I only need a power cord to connect to the G/N/L and then have 3 x 5V outputs I can wire to the pcb board.
Or alternatively I can get 3 independent power blocks like this for these 3 amps... there will be no fan and whould work (?)
thanks again 😉
I would say for one amp the process is this ? :
2x50 = 100W
P=UI
so I = 100/18 = 5.5A ?
is that right ? I feel 5.5A looks high but what do I know ?
Well, the power ideally halves when you connect an 8 ohm instead of a 4 ohm load, but there is also the efficiency of the amplifier to consider, so it's 2.7777... A/efficiency when you play a sine wave at full power. For a class D amplifier, that will be around 3 A, for a class (A)B amplifier, probably closer to 4 A.
As WhiteDragon pointed out, the average will be considerably less with more musical waveforms than sine waves.
My earlier comment about the power being much too high was assuming normal speakers. I have no idea what the sensitivity of a Dayton exciter shaking a part of a sculpture will be.
When you connect a bunch of class D amplifiers to a common power supply, you might get whistles due to unintended frequency conversion effects. What amplifiers do you intend to use?
Hi,
oh thanks I will reconsider these calculation later then.
these are the 2x50W 4ohm amplifers,
these are the 2x3W 4ohm amplifers
oh thanks I will reconsider these calculation later then.
these are the 2x50W 4ohm amplifers,
these are the 2x3W 4ohm amplifers
I see, they are all class D.
The TPA3116D used for the 50 W amplifiers has a couple of features that could be useful to solve whistles, if any. You can change the switching frequency with the pins AM2...AM0, see https://www.ti.com/lit/ds/slos708e/slos708e.pdf , and you can synchronize the amplifiers, as shown here: https://e2e.ti.com/support/audio-group/audio/f/audio-forum/732327/tpa3116d2-sync-functionality-issue In either case, you need to have access to the appropriate pins (AM2...AM0 or SYNC, pins 13...16).
The TPA3116D used for the 50 W amplifiers has a couple of features that could be useful to solve whistles, if any. You can change the switching frequency with the pins AM2...AM0, see https://www.ti.com/lit/ds/slos708e/slos708e.pdf , and you can synchronize the amplifiers, as shown here: https://e2e.ti.com/support/audio-group/audio/f/audio-forum/732327/tpa3116d2-sync-functionality-issue In either case, you need to have access to the appropriate pins (AM2...AM0 or SYNC, pins 13...16).
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thanks,
ouch... whistles, switching frequency.. I have no idea what that means 😵
But also, I don't want to synch the amps do I ? 🤔
ouch... whistles, switching frequency.. I have no idea what that means 😵
But also, I don't want to synch the amps do I ? 🤔
Oh that's the whistles sorry. No I will go all with single power supplies for each amps in the end.When you connect a bunch of class D amplifiers to a common power supply, you might get whistles due to unintended frequency conversion effects.
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