Distortion noise during iTunes playback, but none within DP

[RockNRoll]

Hello all,

Typically, for quick and simple final bounces, I would just merely use a MW limiter on the master bus. Normally, I would just tweak the settings so that I am mildly pushing the overall levels within the MW limiter, as long as I don't hear any distortion or clipping noises. Lately, I have noticed distortion/static noise during the playback of a DP bounced file within ITunes. However, such noises were not heard during the mixing or playback of the same exact wave file within DP. The implications of such a problem could be quite disastrous if in fact the final product contains audible clipping or distortion that can actually be heard within iTunes, but not within your mixing session within DP. It is almost as if I am not actually hearing what I am actually getting within DP at the moment.

My question is what could be some of the main causes of such a discrepancy in audio playback between these 2 platforms? Could it be the MW limiter is faulty? Does the 828 MKII play a role during a bounce to disk process, and if so could it be a sign that the 828 is not working well? or some other possible reasons?

I'm running the latest version of DP6 with an 828 MKII on a Mac Intel Quad desktop with 4GB ram. DP's buffer is set at 1024. Based on the computer performance meter within DP, I am hardly pushing the computer. Also, I have disabled any eq or sound enhancing settings within iTunes.

Appreciate any insight or advice!

Thanks!

[magicd]

You want to make sure that you are not adding any gain after the MW Limiter.

I put it on the last effect insert of the Master Fader and leave the fader at unity gain.

What you might want to try is this. Create a new empty DP file and bring the bounced audio back into this file. Does it distort the same way it does in iTunes?
If so, go back to your original DP file and follow the signal chain. Does the bounce include any tracks that are not going through your final limiter?

Oh yeah, and one other thing - check that you don't have some kind of sound enhancer or other effect going in iTunes.

Any luck?

Dave

[RockNRoll]

You want to make sure that you are not adding any gain after the MW Limiter.

I put it on the last effect insert of the Master Fader and leave the fader at unity gain.

What you might want to try is this. Create a new empty DP file and bring the bounced audio back into this file. Does it distort the same way it does in iTunes?
If so, go back to your original DP file and follow the signal chain. Does the bounce include any tracks that are not going through your final limiter?

Dave

Hi! thanks for your reply! the MW limiter is the only effect on the master bus, and the fader is at unity. I did previously disable all eq enhancers within iTunes. However, despite all of this, I was still hearing noticeable distortion noise during iTunes playback while not being able to hear such anomalies within DP's playback of the same exact file. Any other thoughts? Is there any possible chance that it could be a hardware problem with the 828 or is that irrelevant to this particular scenario?

Thanks for any advice!

[FMiguelez]

.

Do you still have DP open when you play the file in iTunes?

The reason I ask is because this happens to me as well. But it is because some lack of CPU resources. The second I close DP, everything plays back normally. The bigger the DP session, the more likely it is that iTunes, or even listening to files using the Finder, will give me this annoying noise. Just close DP to liberate system resources, and your file will playback correctly (if this is your issue, of course).

Hopefully it is, since the solution is quite simple.

[Splinter]

RnR:

I know exactly what you are talking about. Check that the master fader in iTunes (top left corner) is NOT all the way up (all the way to the right). This is adding gain. It should only be at about 3/4 of the way up - there is no mark for unity. I have an output meter on my DAW and you will see the meter clipping unless you have it in this position. I often hear other songs clip unless this is set properly. The other thing you want to check is the EQ. Make sure it is OFF. It defaults to ON. iTunes is really designed to run with "soundcheck" ON, which auto levels all the songs. If you turn it on and select info on a song, you will see soundcheck is frequently cutting the playback level by 12 -13dB.

[dosuna11]

RnR:

I know exactly what you are talking about. Check that the master fader in iTunes (top left corner) is NOT all the way up (all the way to the right). This is adding gain. It should only be at about 3/4 of the way up - there is no mark for unity. I have an output meter on my DAW and you will see the meter clipping unless you have it in this position. I often hear other songs clip unless this is set properly. The other thing you want to check is the EQ. Make sure it is OFF. It defaults to ON. iTunes is really designed to run with "soundcheck" ON, which auto levels all the songs. If you turn it on and select info on a song, you will see soundcheck is frequently cutting the playback level by 12 -13dB.

This drove me crazy until I discovered it was the problem.

[RockNRoll]

RnR:

I know exactly what you are talking about. Check that the master fader in iTunes (top left corner) is NOT all the way up (all the way to the right). This is adding gain. It should only be at about 3/4 of the way up - there is no mark for unity. I have an output meter on my DAW and you will see the meter clipping unless you have it in this position. I often hear other songs clip unless this is set properly. The other thing you want to check is the EQ. Make sure it is OFF. It defaults to ON. iTunes is really designed to run with "soundcheck" ON, which auto levels all the songs. If you turn it on and select info on a song, you will see soundcheck is frequently cutting the playback level by 12 -13dB.

Thanks! I will look into this further. Pretty crazy how many little unpredictable things could end up being the cause of a problem. Thank goodness for forums.

[Armageddon]

If you're just trying to gauge an accurate playback, and not necessarily how it will sound as an .mp3 on iTunes, you will definitely also want to switch off the Sound Enhancer in iTunes (in Prefs, under "Playback"), which is usually switched on by default. The Sound Enhancer is, as far as I can tell, some sort of a basic compressor, sort of like a mini version of a broadcast comp, and will definitely drive up both the levels and the overall dynamics. I've never experienced a problem with the volume controls in iTunes, which sound exactly as loud as the volume controls in QuickTime jacked all the way up, but the Sound Enhancer in iTunes will definitely alter the sound from what it sounded like in DP or QuickTime. Play one of your mixes in iTunes, and, while it's playing, switch on and off the Sound Enhancer and see if you can tell a major difference. You will definitely hear things with the Sound Enhancer on that you wouldn't have heard in DP when you were mixing.

However, an even better bet would be to leave the Sound Enhancer on and A-B roll your DP mix with a commercial one that you believe to be around the same levels. iTunes default is a great litmus test for your mixes, especially comparing them to commercial ones in the same environment, because that's probably how most people will wind up listening to your stuff. Chances are high that, if you're hearing distortion in your mixes on iTunes and not in a commercial one that sounds about as loud, you might be using too much compression/limiting, or your analog modeled comp or limiter is over-hyping certain bandwidths. Try bumping up all the individual track volumes in your mix by 1 dB or so, then decrease the limiter threshold or input by the same amount. Now, that extra 1 dB of volume is coming from your mix, and not from limiting or compression, and when the track gets additional compression inside of iTunes' Sound Enhancer, it won't sound over-compressed. 1 dB is a good starting point, but you can try trading off 2 or even 3 (though 2 might be a safe spot to stop). You can also try switching to a different comp or limiter that doesn't necessarily model analog gear and applying the same basic settings -- like I said, some analog-modeled stuff hypes up certain EQ bands to sound "warm" or "analog", and that could actually be altering the overall EQ of your material in a way you don't want.

[cbergm7210]

R n R, as Magic Dave suggested, have you dragged your final two track mix back into a new DP session and listened for distortion there? That will definitively tell you if your mix is indeed distorted or whether ITunes is the culprit.

Chris