Amplify vs Normalize parameters

[Charlie Nash]

I have read all the tutuorials on both Amplify and Normalize. I have also searched the Forum on this topic and read everything that I could find. I do not have any DC Offset in my recordings and my system seems to be reasonably balanced. I have therefore decided that I should use Amplify instead of Normalize. But I notice that the default settings in Audacity are different for the two methods. Normalize defaults to -1.0 dB. Amplify defaults to 0.0. Is there a reason for this? When I use Amplify which setting do you recommend that I use?
Charlie Nash

[steve]

I usually use Normalize as it retains my preferred setting (Amplify always defaults to 0dB in Audacity 1.3.12 but I usually prefer to keep a bit of headroom before exporting, so generally Normalize to around -0.1 dB). The case where Amplify should be used rather than Normalize is if the peak levels in left and right channels are significantly (and deliberately) different.

Normalize will always amplify the left and right channels independently so that both channels have the same peak level. Often this is fine, but occasionally one channel will have higher peaks than the other channel that you want to retain (keep the original left/right balance) in such cases you need to use the Amplify effect as this amplifies Left and Right by the same amount and so retains the original Left/Right balance. You can set the target level of the amplify effect to anything you like - as with Normalize I usually adjust it to around -0.1 dB before exporting the final audio file, but this needs to be set each time the effect is used as it reverts back to 0dB in Audacity 1.3.12 (some lower level in Audacity 1.2.6)

[whomper]

one pushes both channels to max so stereo may become unbalanced
one pushes both until the highest one hits its max but both by the same amount so if one is lower to start it stays lower

its just numbers - defaults the coder liked i suspect
i always leave at least 1dB under the max with either
some folks push to 1/2 or closer - maybe even touching 0.0

you really cant hear the difference
so why risk problems that could occur
with some playback devices

[waxcylinder]

Snip from my reply to your workflow/filter posting

<<<I use the Amplify effect and not the Normalize effect to bring the level up to -1.0dB (Amplify works equally on both channels, Normalize works on each channel independently and thus the stereo balance can be impaired)>>>

WC

[steve]

thus the stereo balance can be impaired)>>>

or corrected.
Most modern commercial recordings have been mastered with the maximum peak level close to or at 0dB. If the transfer of a tape or record into digital has come through with one channel peaking higher than the other, it may be due to an unintentional left/right imbalance in the playback/Audacity recording. For example, if recording through a pre-amp with independent channel controls, they may not have been set exactly the same, or for a cassette there may be a small alignment error of the tracks on tape with the play heads (if this latter issue occurs regularly the tape head alignment should be corrected). In such cases, Normalize can be useful to bring left and right back into balance.

It would be really nice to have an option to select "Link stereo channels" so that the user can choose which they want.
It would be especially useful for using in batch mode (chains).
There is already a feature request for this. If you agree, please vote for it.

An option to calculating the track gains together to avoid changing the stereo balance: When multiple tracks are selected, only the highest peak level of ALL tracks should be considered to adjust each track by the same amount so that the volume of each track relative to each other will stay the same. (1 votes)

http://wiki.audacityteam.org/wiki/Featu ... to_Effects
(if you do not have an account for the wiki, you can voice your vote here and one of the forum moderators will transfer it to the wiki).

[Charlie Nash]

WC,
I'm a little confused. While your recommendation sounds correct, is this not what normalize already does?

Also, I find it interesting that you choose to use "Amplify" whereas Steve chooses to use "Normalize". I gather, however, from reading your past Postings that you do a lot of Vinyl transfer, whereas Steve states that he does very little Vinyl transfer. Would this be the primary reason that the two of you opt for different methods?
Charlie

[steve]

Since WC is not on-line at the moment but we are...

Having done hundreds of vinyl transfers, waxcylinder has his set-up precisely tuned for producing high quality recordings from vinyl. He knows that the recording that he gets will be very close to the original sound of the record and that the left/right balance is correct.

If say the left channel of his recording has a higher peak than anything on the right channel, then that is because that is the way that it is on his original vinyl.
In such a case, if he used the "Normalize" effect, the left/right balance would be changed because both the left and right channels would be adjusted independently to create a maximum peak at the set level in both channels. That is not what he wants - he wants to amplify both channels equally so that the left/right balance is unchanged. To achieve equal left and right channel amplification, the Amplify effect must be used.

I will generally use Normalise for the reasons described earlier, though I'll use Amplify if I specifically need to amplify both channels by the same amount.

I find it interesting that you choose to use "Amplify" whereas Steve chooses to use "Normalize"

Both approaches are perfectly valid which is why I would urge people to vote for having the option to choose "Link stereo Channels".

[waxcylinder]

WC is on the line - but he was in the middle of typing a long reply when the forum crashed - and the msg got lost

In the meantime Steve has said most of what I was going to say.

I am pretty confident that my equipment is well balanced. As Steve says, think about a recording where the left channel say has a very loud noise that is not present on the right channel. Normalize will look at each channel independently and thus will probably over-amplify the right channel - whereas Amplify will amplify them both the same, retaining the original balance.

Unless you are unlucky, I would expect the kit that you have that you listed for us to be pretty well balanced provided you set it up right. You may however find the odd original recording which is not properly balanced - and you may want to adjust that, consider Normalize in that case.

WC

[Charlie Nash]

Steve,
I went out to the Wiki a few minutes ago and read the recommendation regarding this. It sounds like the whole situation might be clarified somewhat if Normalize and Amplify were transformed into only one instead of two choices, but with the option that you and WC are recommending. Seems like everyone would then have what they needed (channels either tied together or calculated separately) without the confusion of Amplify vs Normalize.

As for my situation, ie, transferring Vinyl to CD, it seems like WC's vast experience with this dictates that I should follow his methodology of using Amplify. Do you think it makes any difference?
Charlie

[waxcylinder]

Charlie,

I went out to the Wiki a few minutes ago and read the recommendation regarding this. It sounds like the whole situation might be clarified somewhat if Normalize and Amplify were transformed into only one instead of two choices, but with the option that you and WC are recommending. Seems like everyone would then have what they needed (channels either tied together or calculated separately) without the confusion of Amplify vs Normalize.

Yup that is what we would indeed like ...

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one piece of advice - I would suggest that you start out working with some of the LPs that you care about least as your technique and skills will undoubtedly improve with time. I mistakenly started out with some of my favourite LPs and then had to go back and do them all over again when I realized that my capture and processing had improved. Even now I'll get the odd track on my iPod shuffle and think I could have done that better

WC