Volume control in dac and decibels

[Juampa1989]

Hello, I have a question if I have a 116db sinad dac and I control the volume on the dac, how much can I lower it so that it stays at 16 bits. I understand that it is 96db. But how do I measure this? Are they db spl? Or is it measured with the vrms? When lowering each volume step, how can I know how many dB I am lowering? I want to control the volume with the dac because my amp doesn't have a remote control. I also don't know if I'll notice a difference in practice.

 

[staticV3]

if I have a 116db sinad dac and I control the volume on the dac, how much can I lower it so that it stays at 16 bits.

That depends on the DAC's Dynamic Range. For example, with 120dB DR, you can lower the volume by 24dB (120-96=24) and still retain 16 bits of DR.

Please note that in practice, the bottleneck is almost always your listening environment, ears, or amplifier. Not the DAC or the audio format.

I understand that it is 96db. But how do I measure this? Are they db spl?

No. They're dB(Z) DR.

When lowering each volume step, how can I know how many dB I am lowering?

You can use a multimeter to measure the voltage reduction, then convert that to dB using http://www.sengpielaudio.com/calculator-levelchange.htm

 

[Juampa1989]

Thank you sir

 

[Juampa1989]

That depends on the DAC's Dynamic Range. For example, with 120dB DR, you can lower the volume by 24dB (120-96=24) and still retain 16 bits of DR.

Please note that in practice, the bottleneck is almost always your listening environment, ears, or amplifier. Not the DAC or the audio format.


No. They're dB(Z) DR.


You can use a multimeter to measure the voltage reduction, then convert that to dB using http://www.sengpielaudio.com/calculator-levelchange.htm

Since the bottleneck is probably not the dac, then I don't need to worry about turning down the volume on the dac. I was thinking of calibrating so that half the volume is the minimum that I want to leave and the maximum is the loudest that I would tolerate, around 95 db spl at peak. The DAC has 117 dB of dynamic range.

 

[JeffGB]

If you are using Windows, you can go into the dac advanced settings and right-click on the volume setting to change from % to db for the display.

 

[AnalogSteph]

Since the bottleneck is probably not the dac, then I don't need to worry about turning down the volume on the dac. I was thinking of calibrating so that half the volume is the minimum that I want to leave and the maximum is the loudest that I would tolerate, around 95 db spl at peak.

Digital volume controls on DACs generally operate with 32 bits worth of precision these days, so you technically wouldn't lose any down to -96 dB... although obviously the signal would increasingly disappear underneath the DAC's analog noise floor below -21 dB. If you can't hear that either, it's not an issue.

BTW, you can calculate dB SPL if you know all of:

1. DAC 0 dBFS level
2. overall amplifier voltage gain and
3. speaker sensitivity

Well, at least in an anechoic chamber, but the rule of thumb is SPL at 2.5-3 m ~= SPL at 1 m anechoic (specifics depending upon the room).

In any case it is extremely linear, so a step of 1 dB is always going to be 1 dB. If there is an appreciable deviation from that, something in the signal chain is distorting heavily... (That's why it's called nonlinearity.)

If you see a 0-100 (or 1-100) volume scale on a DAC or AVR, it is usually a shifted dB scale. Apparently people are not to be trusted with negative numbers or something. (I disagree. It's just a matter of getting used to.) The 0-100 scale on Windows is not as you'll find out when switching to dB display, I think it's supposed to emulate a fader pot.