… is it possible to translate mV output to increase in db?
- Thread starter skinnyfla
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4mV is 6dB higher than 2mV. For example output of phono stage at 34dB gain and 4mV cartridge should be the same at 40dB gain with 2mV cartridge.
.... okay - 6db should be enough to make a small difference in volume raise on preamp, right?
A .5 dB difference ( 5% variation in voltage) is considered enough to bias a choice. -6dB is a reduction of 50% of voltage. IMO it is a large variation.
Rarely manufacturers’ specifications for output matches the actual output of cartridges. There is also the issue of measuring speed, some measure at 3.54cm/s instead standard 5cm/s.
dB is a ratio. For voltage, given two voltages V1 and V2, the ratio in dB is 20*log10(V2/V1) so 20*log10(.004/.002) = 6.021 dB. Also, that is a 100% increase when you double the voltage.
The volume control may use a special "taper" so the change is not linear, or linear in dB, as you turn the control so in general I can say that, all else equal, you would have to turn the volume down "some" but without knowing more detail I could say how how much. If it is calibrated in dB, then you'd turn it down 6 dB. If it is just numbers, hard to say... Volume controls are rarely linear (1:1 change in voltage) because that is not how our hearing works. It may be linear in dB, so each increment is a fixed number of dB, but even that is not guaranteed without knowing exactly what volume control you are using. But it really does not matter.
Here is what I have posted before about dB changes (though for power, 10log10 instead of 20log10, but the dB works out, and gives you an idea what to expect).
---
Power Needs:
For many years I have used 17 dB peak-to-average power based on an old AES article I can no longer find. Anecdotally various audio fora report 20 dB or more for movies. IME most people use much less average power than they think, but require more peak power. An online calculator can help you estimate your average power; note 80 dB is very loud to me (YMMV). Here is one:
Most people think of volume in dB and most modern AVR/AVP/etc. units list dB on the volume knob. Power in dB goes as 10log10(Power_ratio) so the change in power is 10^(dB/10). Here are some reference numbers in dB and power:
1 dB is barely noticeable and requires 1.26x the power
3 dB is what most people hear as "a little louder" and requires 2x the power
6 dB is significantly louder and requires 4x the power
10 dB sounds twice as loud and requires 10x the power
17 dB is the headroom for music and requires 50x the average power
20 dB for movies requires 100x the power
If you listen at around 1 W average, then you need 50~100 W to avoid clipping on most source material. You can figure out your estimated average power from the calculator knowing your speaker's sensitivity and distance from them. Note music may be more compressed and thus require less headroom, and the loudest sounds in movies tend to be things like gun shots and explosions where a little clipping is likely unnoticeable.
HTH - Don
The volume control may use a special "taper" so the change is not linear, or linear in dB, as you turn the control so in general I can say that, all else equal, you would have to turn the volume down "some" but without knowing more detail I could say how how much. If it is calibrated in dB, then you'd turn it down 6 dB. If it is just numbers, hard to say... Volume controls are rarely linear (1:1 change in voltage) because that is not how our hearing works. It may be linear in dB, so each increment is a fixed number of dB, but even that is not guaranteed without knowing exactly what volume control you are using. But it really does not matter.
Here is what I have posted before about dB changes (though for power, 10log10 instead of 20log10, but the dB works out, and gives you an idea what to expect).
---
Power Needs:
For many years I have used 17 dB peak-to-average power based on an old AES article I can no longer find. Anecdotally various audio fora report 20 dB or more for movies. IME most people use much less average power than they think, but require more peak power. An online calculator can help you estimate your average power; note 80 dB is very loud to me (YMMV). Here is one:
Most people think of volume in dB and most modern AVR/AVP/etc. units list dB on the volume knob. Power in dB goes as 10log10(Power_ratio) so the change in power is 10^(dB/10). Here are some reference numbers in dB and power:
1 dB is barely noticeable and requires 1.26x the power
3 dB is what most people hear as "a little louder" and requires 2x the power
6 dB is significantly louder and requires 4x the power
10 dB sounds twice as loud and requires 10x the power
17 dB is the headroom for music and requires 50x the average power
20 dB for movies requires 100x the power
If you listen at around 1 W average, then you need 50~100 W to avoid clipping on most source material. You can figure out your estimated average power from the calculator knowing your speaker's sensitivity and distance from them. Note music may be more compressed and thus require less headroom, and the loudest sounds in movies tend to be things like gun shots and explosions where a little clipping is likely unnoticeable.
HTH - Don
Although "tapers" are commonly used to change the potentiometer response, since long most audio equipment use logarithmic potentiometers, such as the commonly used 50 or 100k Alps potentiometer in Audio Research equipment, for example. However the issue with the cheap logarithmic potentiometers is channel imbalance - it is harder to keep accurate balance in non linear scales.
Resistive high quality stepped potentiometers or attenuators are also available in logarithmic scale. It is why most of the time we have a feeling of linear increase of the perceived loudness versus button position when changing volume.
Yah, there used to be a special "audio" taper that was not purely logarithmic, but these days a lot of equipment has gone to linear in dB steps. That may be more the AVR world, though, I do not know. Log taper is pretty much standard in the audio world AFAIK, to better match our hearing of perceived loudness, like you said.
The imbalance issue, especially at low levels, has been with us a while but my gut says seems to be getting worse? Again not something I have delved into enough to say. So much has gone to digital control (direct or digital-controlled attenuators/FETs) that I have lost track. FETs need to be well-matched for volume control, natch.
NP. I mentioned but glossed over voltage vs. power in dB... Power goes as voltage squared so that makes the dB the same when you double the voltage.
2x the voltage is a 6 dB increase in voltage: 20*log10(2) = 6 dB.
2x the voltage is a 4x increase in power (2^2 = 4), but is still a 6 dB increase in power: 10*log10(4) = 6 dB.
For power (P), voltage (V), and resistance (impedance magnitude) R: P = V^2 / R
HTH - Don
… in the end, for a technical dumbass like myself, 0.4 mV should be louder than 0.2 mV at same volume level, right?
As for the imbalance, doesn’t Audio Note get it right with the two completely separated volume controls for the left and right channel?
As for the imbalance, doesn’t Audio Note get it right with the two completely separated volume controls for the left and right channel?
Yes, it will be noticeably louder, for the same source material (spot on the record).
Note ignorance does not mean stupid, no worries.
What matters is how well the controls are matched, whether combined in one case (or on one shaft) or not. Could be better or worse, all depends upon their manufacturing and acceptance/selection criteria. I have seen imbalance numbers all over the map but have no idea how well Audio Note does in that regard. I would expect the worst mismatch with inexpensive plastic resistive potentiometers (pots, volume controls) but those could be manufactured and/or selected for close tolerances, just won't hold tolerance as long as something like a good stepped attenuator.
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