Hi, following that topic
I would like to calibrate 8 of those amplifiers
The speakers I'm using are those 8r 30w
The power I'm feeding the amps is 24V
How can I calibrate those amplifiers?
What output I should aim for?
I have an audio interface so I can output as in wave to the amplifier input and calibrate the output using a digital multimeter
Thanks for any advise
I would like to calibrate 8 of those amplifiers
The speakers I'm using are those 8r 30w
The power I'm feeding the amps is 24V
How can I calibrate those amplifiers?
What output I should aim for?
I have an audio interface so I can output as in wave to the amplifier input and calibrate the output using a digital multimeter
Thanks for any advise
Sounds like you want to determine the voltage gain of your amplifier. Just measure the AC voltage at the input and and the output. I'd recommend you use a sine signal of maybe 100 Hz, where most DVMs will give good readings.
Yes exactly that.
Another thing I try to understand is that if the amplifiers are rated for 100w output but my speaker can take only 30w. How should I calibrate for that?
What voltage peak to peak I should measure at the output knowing my speakers can power 30w maximum
If all amps and all speakers are the same you can use the output voltage method.
In reality, speakers will likely be positioned at a different distance from the listening position.
In that case I would do it "by ear".
Power = Voltage x voltage divided bij nominal speaker impedance. E.g. 3V output with 8 ohm speakers would give you (3 X 3) / 8 = about 1.13 Watt.
Hugo
In reality, speakers will likely be positioned at a different distance from the listening position.
In that case I would do it "by ear".
Power = Voltage x voltage divided bij nominal speaker impedance. E.g. 3V output with 8 ohm speakers would give you (3 X 3) / 8 = about 1.13 Watt.
Hugo
If impedance is not listed, you can measure it with an Ohm meter.
Say you measure +/- 7 Ohm then the speaker would be 8 Ohm.
If you measure +/-3 Ohm it will be 4 Ohm.
With the formula above you want to know the max. voltage to be applied to the speaker.
That would be V² = R X P.
For 8 Ohm that would be 8 X 30 = 240.
Square root of 240 = 15.5V
Now you can calculate the same if your speakers would be 4 Ohm.
I wouldn't apply 15V to those speaker though.
I bet for normal listening levels you'll have plenty with half that voltage, wich would be 7 Watt.
The rest is headroom for peaks (and parties 🙂 )
Hugo
Say you measure +/- 7 Ohm then the speaker would be 8 Ohm.
If you measure +/-3 Ohm it will be 4 Ohm.
With the formula above you want to know the max. voltage to be applied to the speaker.
That would be V² = R X P.
For 8 Ohm that would be 8 X 30 = 240.
Square root of 240 = 15.5V
Now you can calculate the same if your speakers would be 4 Ohm.
I wouldn't apply 15V to those speaker though.
I bet for normal listening levels you'll have plenty with half that voltage, wich would be 7 Watt.
The rest is headroom for peaks (and parties 🙂 )
Hugo
Thanks!
And what I should be at my input? (Assuming I'm outputting sine wave at unity gain from my soundcard
And what I should be at my input? (Assuming I'm outputting sine wave at unity gain from my soundcard
Best to find out as mbrennwa explained.
Measure the output with a fixed voltage (+/- 100Hz) applied to it
and look what voltage you read at the input.
Measure the output with a fixed voltage (+/- 100Hz) applied to it
and look what voltage you read at the input.
So I'm outputting sine wave at unity gain from my soundcard and im measuring 3.41V with my multimeter set to AC
If this the output of my soundcard I should then measured 7V at the output of my amplifier?
If this the output of my soundcard I should then measured 7V at the output of my amplifier?
Not necessarily. It depends on the gain of the amplfier.
Start at the output of the amp. If you measure say 10VAC at the output and 1VAC on the input the gain is 10 (10*1)
If your soundcard outputs 3.41VAC and the gain is 10 you will measure 34.1VAC at the output.
If the gain is 20 you will measure 3.41 * 20.
Gain = output voltage / input voltage.
Hugo
Start at the output of the amp. If you measure say 10VAC at the output and 1VAC on the input the gain is 10 (10*1)
If your soundcard outputs 3.41VAC and the gain is 10 you will measure 34.1VAC at the output.
If the gain is 20 you will measure 3.41 * 20.
Gain = output voltage / input voltage.
Hugo
Isn't it better to set the output voltage of the amp to be able to drive the speakers at their max watt (30w) and then reducing the volume from the audio software?
How much voltage would go the the speakers if your amp would have a gain of 20 and your input is 3.41V?
Hugo
Hugo
Obviously that would be too much. But if the speaker can have power of 30w and for that we need output voltage of 15V - isn't it better to calibrate the amp output to that voltage?
Then any reduction in sound will be done from the soundcard (?)
Then any reduction in sound will be done from the soundcard (?)
You have nothing to calibrate.
I guess you want to know how NOT to blow your "30W" speakers with your "100W" amplifiers so find how much "safe" signal you can feed them.
If anything, what you are asking and is being answered is about Lab type measurements ... but you will not listen to continuous sinewaves, I would guess Music instead.
What is your Music program source?
1) speakers claim standing 30W RMS so we'll trust that for now
2) your "100W" amps can actually put out 30W RMS into 8 ohm speakers when fed 24VDC, so in principle they are matched.
3) just plug your music source into your amp, once rise volume until they start sounding ugly (clipping), only for 10-20 seconds is enough, lower volume, and never surpass that.
Presto! You have just calibrated your system.
As long as you use your system "clean", not like a DJ who is all time slamming his speakers, you'll be fine.
Your average volume will be less than 30W RMS per speaker.