A Test. How much Voltage (power) do your speakers need?

[JRKO]

Going on original instructions - its been a while since I looked over here.

With the -18db sounding like Niagra I hit 152.3 millivolts. So 0.4v rms

I need to go back to school

[Pano]

OK, sounding like Niagra? You were using the pink noise? Please try the -12dB sine wave files. Pick the frequency that works best for your system.

[regal]

Just to give folks an idea of how hard it is to power new ortho headphones, I measured 1.3Vrms with the -12db tracks, thats higher than the majority of speakers meaurements in the poll.

[jakubg]

Originally Posted by regal

Just to give folks an idea of how hard it is to power new ortho headphones, I measured 1.3Vrms with the -12db tracks, thats higher than the majority of speakers meaurements in the poll.

Don't forget that headphones usually have higher impedances.
Therefore 1.2V into 60 ohms (audeze LCD2) is 0.024 watts.
Its the same as 0.44V into 8 ohms.

But still, it's a lot of power for headphones (remember you are listening centimeters away, not meters like with speakers).

[pierre77]

Dear Pano

thanks for the post, I'll take the test asap. I am struggling with the "gain staging" problem.... I never thought about it before I strated to play with active xover!. It's damn important, I realize!

I have the following basic question which has somehow to do with gain-staging and this voltage test all together.

Suppose my speaker have:
Z_min = min impedance across the spectrum,
S = speaker sensitivity in dB/2.83V/1m, anechoic

I want to produce X dB at the Y meters under anechoic conditions. How do I compute:
1. Vmax = the voltage required by the amp
2. Imax = the current need

I hope somebody can give me forumlae to compute those quantities.

Best Regards
Pierre
Ps: I may try to answer that answer that Imax=Vmax/Zmin,

[weltersys]

Originally Posted by pierre77

I want to produce X dB at the Y meters under anechoic conditions. How do I compute:
1. Vmax = the voltage required by the amp
2. Imax = the current need

Pierre,

Voltage x Voltage divided by impedance=watts.

SPL drops at 6 dB per doubling of distance outdoors or in an an anechoic chamber.
A 90 dB one watt one meter speaker driven with 10 watts will be 100 dB, at 2 meters 94 dB, at 4 meters, 88 dB etc.
Assuming a nominal 8 ohm speaker, the 10 watts would require 8.944 volts.

[Pano]

And as mentioned, that is outdoors or with no reflections. It usually does not drop what fast in a room. If you are in a room, I suggest pink noise playing on both speakers and an SPL meter.

For example: With both speakers playing I get ~84dB at my listening position with 1V on the speaker terminals. I'm not sure what that translates into for each speaker a 1W/1M, but I know the voltage I need to hit 84dB where I sit.

[Lavcat]

Speaking of headphones, for my nominal 25 ohm Denon D7000's I measured 0.336v using Pano's -12dB test tone.

[Vaughan]

This method won't determine sudden changes in signal amplitude? If I'm watching a movie like Master and Commander, Chapter 4, before the cannons start, there is almost silence but when the action hits it hits very hard.

Now how would one determine how much voltage was used during those sequences? Because people say you need "x" watts to watch a movie and that more power will help in a given scene.

It would be interesting to put that to the test to test dynamic events from movies at a loud volume and see how much power is being used.

[mr_push_pull]

Originally Posted by Vaughan

It would be interesting to put that to the test to test dynamic events from movies at a loud volume and see how much power is being used.

it would be just the same thing done in this thread.
are you sure you read and understood the procedure?
nevertheless, everyone is free to believe that there are occult/unmeasurable phenomena at play.