Flac to Flac

[astral]

I recently downloaded a recording in FLAC 16 bit 44khz

The volume level is very low, some 10db below what I expect.

So I ran it through FormatFactory with a 200% volume increase, nothing else.

The volume level is now much better, but have I corrupted the quality??

Not sure my ears can tell, but any technical comments welcome.

Thanks

Astral

[IMHO]

Not familiar with tool you've used, but I assume 200% means +6dB?

One thing that has happened for sure is the noise floor has been raised by the amount of gain - whether or not that's going to be audible really depends on just how quiet the track gets, and how low the noise floor was to begin with.

Assuming the tool used applied linear gain and nothing else, and that there's been no clipping or dynamic compression introduced (both easy to do if over-gaining), the noise floor should be the only change.

Edited July 3, 2013 by IMHO

[astral]

Thanks for those comments

I think 200% is only 3db

as the options offered also allow for reduction in level to 30% 50% etc

[AngelsLariat]

There will be some loss, at least mathematically. Whether it audible affects sound quality is another matter though.

It sounds like what you did is similar to what ReplayGain does on-the-fly (but without altering the original flac files) when you play back recordings that have different average volume levels. Not sure how you're playing back your flac files, but you might want to check out foobar2000 for a versatile player that can handle such issues with few hassles.

[astral]

An external player is not in the equation.

The files are on a hard disk and played directly by the DAC in my Yamaha AV amp

[AngelsLariat]

An external player is not in the equation.

The files are on a hard disk and played directly by the DAC in my Yamaha AV amp

Thinking about your question further, I think that it depends upon the algorithm that FormatFactory is using to boost the gain and whether there is any content in the original flac file that is encoded higher than -6dB. If there is no data in your original file louder -6dB then I think that it should be possible to losslessly boost the gain 6 dB just by shifting each word of data by 2 bits. However if you do that, any content with encoded at higher than -6dB will cause clipping.

[astral]

I am hoping something like that may be true

Thank you for the insight.

[IMHO]

An external player is not in the equation.

The files are on a hard disk and played directly by the DAC in my Yamaha AV amp

Thinking about your question further, I think that it depends upon the algorithm that FormatFactory is using to boost the gain and whether there is any content in the original flac file that is encoded higher than -6dB. If there is no data in your original file louder -6dB then I think that it should be possible to losslessly boost the gain 6 dB just by shifting each word of data by 2 bits. However if you do that, any content with encoded at higher than -6dB will cause clipping.

It all depends on what your definition of 'lossless' is

Yes, it's possible to add gain without losing any data, but no matter what you do you're certainly gaining data - in the form of an increased noise floor

[AngelsLariat]

An external player is not in the equation.

The files are on a hard disk and played directly by the DAC in my Yamaha AV amp

Thinking about your question further, I think that it depends upon the algorithm that FormatFactory is using to boost the gain and whether there is any content in the original flac file that is encoded higher than -6dB. If there is no data in your original file louder -6dB then I think that it should be possible to losslessly boost the gain 6 dB just by shifting each word of data by 2 bits. However if you do that, any content with encoded at higher than -6dB will cause clipping.

It all depends on what your definition of 'lossless' is

Yes, it's possible to add gain without losing any data, but no matter what you do you're certainly gaining data - in the form of an increased noise floor

Don't think so. That increases the noise floor only in the sense that turning up an analog volume control increases the noise floor. Yes, the noise will get louder, but the signal-to-noise ratio will remain unchanged. No data is added - perhaps truncated (clipped) or perhaps changed due to round off error if the gain is boosted by an odd amount, but not added.

The reason that I say that boosting the gain 6 db by shifting the bits of the each word of data is lossless is because (provided that it doesn't cause clipping to occur) it would be completely reversible. In that scenario, though your data has 16 bit words only 14 bits are really being used and all the shifting does is leave a different 2 bits unused. You could still perfectly reconstruct your original data just by shifting it back 2 bits and nothing would be lost.

[IMHO]

An external player is not in the equation.

The files are on a hard disk and played directly by the DAC in my Yamaha AV amp

Thinking about your question further, I think that it depends upon the algorithm that FormatFactory is using to boost the gain and whether there is any content in the original flac file that is encoded higher than -6dB. If there is no data in your original file louder -6dB then I think that it should be possible to losslessly boost the gain 6 dB just by shifting each word of data by 2 bits. However if you do that, any content with encoded at higher than -6dB will cause clipping.

It all depends on what your definition of 'lossless' is

Yes, it's possible to add gain without losing any data, but no matter what you do you're certainly gaining data - in the form of an increased noise floor

Don't think so. That increases the noise floor only in the sense that turning up an analog volume control increases the noise floor. Yes, the noise will get louder, but the signal-to-noise ratio will remain unchanged. No data is added - perhaps truncated (clipped) or perhaps changed due to round off error if the gain is boosted by an odd amount, but not added.

The reason that I say that boosting the gain 6 db by shifting the bits of the each word of data is lossless is because (provided that it doesn't cause clipping to occur) it would be completely reversible. In that scenario, though your data has 16 bit words only 14 bits are really being used and all the shifting does is leave a different 2 bits unused. You could still perfectly reconstruct your original data just by shifting it back 2 bits and nothing would be lost.

The first part of your post sounds like you're disagreeing with me, but the rest of it sounds like you're agreeing - all good

[AngelsLariat]

Thinking about your question further, I think that it depends upon the algorithm that FormatFactory is using to boost the gain and whether there is any content in the original flac file that is encoded higher than -6dB. If there is no data in your original file louder -6dB then I think that it should be possible to losslessly boost the gain 6 dB just by shifting each word of data by 2 bits. However if you do that, any content with encoded at higher than -6dB will cause clipping.

It all depends on what your definition of 'lossless' is

Yes, it's possible to add gain without losing any data, but no matter what you do you're certainly gaining data - in the form of an increased noise floor

Don't think so. That increases the noise floor only in the sense that turning up an analog volume control increases the noise floor. Yes, the noise will get louder, but the signal-to-noise ratio will remain unchanged. No data is added - perhaps truncated (clipped) or perhaps changed due to round off error if the gain is boosted by an odd amount, but not added.

The reason that I say that boosting the gain 6 db by shifting the bits of the each word of data is lossless is because (provided that it doesn't cause clipping to occur) it would be completely reversible. In that scenario, though your data has 16 bit words only 14 bits are really being used and all the shifting does is leave a different 2 bits unused. You could still perfectly reconstruct your original data just by shifting it back 2 bits and nothing would be lost.

The first part of your post sounds like you're disagreeing with me, but the rest of it sounds like you're agreeing - all good

All that I’m trying to say is that if the file was encoded at that low of a level then probably the two most significant bits of each word’s worth of data are zero. If that’s the case, there is no harm in shifting the data two bits to the left and discarding the leading zeros. If, on the other hand, there are some words of data in the file encoded with a value greater than 0011111111111111 (assuming a 16 bit word length for both the inputted and outputted flac file) then something is going to be lost if the volume is boosted by multiplying each word by 4.

[astral]

If I have to increase the volume on my amp to listen

that also amplifies the noise?

[AngelsLariat]

If I have to increase the volume on my amp to listen

that also amplifies the noise?

Both the signal and the noise will be amplified by the same amount.

Edited July 25, 2013 by AngelsLariat