Old 10-25-2016, 11:26 AM   #1
otb
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Default Sound Quality - explanation?

Hi!
I love Reaper, but I often wonder about the sound quality.

First) Reaper has always approached the project maxing out with that "stuttering" playback thing.
That's fine I don't hate it. But I can't help but worry, is it happening at times in an inaudible way? There's no control over it, no meters to tell me how much if it is happening. And no way to turn it off so I can know that my audio is being compromised. Working OTB, it would be nice to walk away from a mix while its rendering stems and not worry about it. ie, if it stops playback I know it couldn't make it the whole way.

Second) The first problem leads to worries about the playback integrity. I always tell myself its psychological/That its my imagination (ie ProTools *sounds* better than Reaper for example).

But now I can test Reaper against audio output from another program using same soundcard: 2015 Macbook Pro line out & built-in speakers. And man, there is a serious difference between the way itunes plays a aif or wav file, and the way Reaper plays the same file, through same output and speakers.
iTunes, the files sound gorgeous and glorius, wide and 3D. Sounds same louldness, just clearer and wider.
Reaper, it sounds flat, flat, and somewhat boring like I expect it to. The difference sounds like a generation loss.

What is going on? Is itunes using some sort of playback engine that makes things sound prettier? Or is Reaper playback engine behind the curve?

It reminded of what I used to "feel" from working in protools, though could never test because the interfaces wouldn't share with programs.

Last edited by otb; 10-25-2016 at 12:51 PM.
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Old 10-25-2016, 11:48 AM   #2
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I've not heard anything "flat" like you mentioned. The DAW shouldn't add or subtract from the audio, so I would look elsewhere. For example, I've heard a difference in iTunes at one times... It turned out that my iTunes had some settings for "enhancement" turned on. Certainly check for that. With those turned off, I was fine.

Concerning the stuttering bit, others may be able to answer this better, but I get that when I push my system with heavy usage. I would imagine that it's not a problem until it's a problem, meaning that you won't have any glitching until you hear it. I suppose that you are right about being right on the line and the CPU being overloaded while you are rendering. I've not experienced that personally. You can use the performance meter to check your CPU usage.

I do understand what you mean about the psychology of the issue. Once you think that there ~might~ be an issue, it's hard to trust and listen openly and honestly. I know that others will likely make references to pan laws and all of that when dealing with DAW to DAW comparisons, but this is a different concern.

I cannot speak to the technical side of the playback engine. I think that entire integrity of the program revolves around the idea that the DAW does not get in the way at all. Zero...zilch...nada. It's so vital.

I've not had an issue with Reaper, but I'm willing to listen to your concerns.
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Old 10-25-2016, 11:49 AM   #3
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Originally Posted by otb View Post
Hi!
I love Reaper, but I often wonder about the sound quality.
Welcome otb...

* The short story is "DAW Engines" and quality is a myth for the basis of this thread anyway. Run from the term "Engine" where audio is concerned as fast as you can - consider it a red flag of ignorance.

* Pops and clicks are a resource problem that should never be conflated with audio fidelity.

* There is no need to even go down the path of testing Reaper's audio 'quality' with any other DAW because the only differences you will find (that matter in 2016) will be due to various settings chosen between the two - meaning it can be difficult to take two mixes in two different DAWs and be 100% sure all settings are identical.

* Eventually someone is going to post something about rounding errors and some .0000001% difference (literally), run as fast as you can from that too because it is 100% irrelevant to anything that actually matters in real life.
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Old 10-25-2016, 11:57 AM   #4
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Is itunes using some sort of playback engine that makes things sound prettier?
iTunes has the so called "sound enhancer" that changes the sound, check in the iTunes preferences if that is on. If that is on and you prefer what it does and you insist on getting the same kind of sound out of Reaper, you can probably achieve that with some EQ and stereo widening tricks. (But it of course isn't the correct sound of the original sound material.)
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Old 10-25-2016, 12:26 PM   #5
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I thought about it a little more, and realized I had opened 32bit instead of 64bit Reaper.
Would this be an audible difference, with channel and master outputs at unity?
(I assume apple's itunes operates at 64bit.)

After loading Reaper 64bit and doing some more tests, I realize it sounds very close to itunes and I think maybe there might be a slight loudness difference I'm hearing. For example, If I turn up Reaper a few dB, then the reaper playback seems to sound more "wide/full", more like the itunes version. etc. If I play them both at the same time, adjusting volumes and pans... seems very close. I don't know why, but so far my brain enjoys the highs of the itunes version. Its like the reaper64 version isn't wrong, but sort of the highs feel..very very slightly... different.

Anyway, maybe I'm just suffering from placebo effect. But this isn't first time I've noticed this. I noticed it first when I was listening to reference tracks I downloaded and played back in itunes on mastering speakers, jaw dropping etc... 30 seconds later import into my trusty Reaper, same outputs, and it felt like my team losing the world series. WTF happened? Lol. I must have opened 32bit Reaper I guess???
I'll do some more tests. Hopefully others can maybe check it out on their own when they have time.
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Old 10-25-2016, 12:27 PM   #6
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iTunes has the so called "sound enhancer" that changes the sound, check in the iTunes preferences if that is on. If that is on and you prefer what it does and you insist on getting the same kind of sound out of Reaper, you can probably achieve that with some EQ and stereo widening tricks. (But it of course isn't the correct sound of the original sound material.)
OOOOOOHHHHHHHHhhhhh.... hahaha.

THANK YOU!!!
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Old 10-25-2016, 12:38 PM   #7
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Hmmm..

in iTunes, sound enhancer is turned off. EQ is turned off.

This is the file I'm using:

https://soundcloud.com/soundonsound/...like-this-snow

Streaming from soundcloud sounds a lot like iTunes.


In reaper I want to turn down the highs and bring up some lows. What is wrong with me?

I'm using Reaper5.18/64
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Old 10-25-2016, 01:00 PM   #8
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Originally Posted by karbomusic View Post
Welcome otb...

* The short story is "DAW Engines" and quality is a myth for the basis of this thread anyway. Run from the term "Engine" where audio is concerned as fast as you can - consider it a red flag of ignorance.
I understand where you're coming from, because that's the "knowledge" I tell my clients !

Quote:
* Pops and clicks are a resource problem that should never be conflated with audio fidelity.
And what about MP3 compression? Reaper would never use that kind of trick, right? I mean compression is convenient way to gain resources back. Without a way to control playback integrity, and given The Creator's prior products (please forgive me for my sins... I'm a reaper fanboy for sure ---I can't help but wander in thought to a dark, frightening, place of doubt...

Quote:
* There is no need to even go down the path of testing Reaper's audio 'quality' with any other DAW because the only differences you will find (that matter in 2016) will be due to various settings chosen between the two - meaning it can be difficult to take two mixes in two different DAWs and be 100% sure all settings are identical.
This is what I'm thinking. Some setting is messed up. Or you know imagination.. (psst* I'm not saying there might be a bug in the kitchen, but, uh.....)

Quote:
* Eventually someone is going to post something about rounding errors and some .0000001% difference (literally), run as fast as you can from that too because it is 100% irrelevant to anything that actually matters in real life.
Well sure, its a standard of coding practice to properly manage your rounding errors so they don't get out of control. I do notice fabfilter sounds really freeking good though, and its pretty light on CPU resources. What did those guys discover? (aside from placebo and MP3 EQ haha)
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Old 10-25-2016, 02:20 PM   #9
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iTunes has a different MP3 decoder, compared to Core audio. Lately, I have the feeling this decoder seems to favor higher bitrates. Low bitrate mp3's seem to sound a lot worse. But I have to compare from memory and that is not very reliable.

Maybe that's because Apple has been trying to push HD audio sales?

Anyhow, the question is if it still sounds better from iTunes if you play back wav files.
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Old 10-25-2016, 03:10 PM   #10
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iTunes has a different MP3 decoder, compared to Core audio. Lately, I have the feeling this decoder seems to favor higher bitrates. Low bitrate mp3's seem to sound a lot worse. But I have to compare from memory and that is not very reliable.

Maybe that's because Apple has been trying to push HD audio sales?

Anyhow, the question is if it still sounds better from iTunes if you play back wav files.
Yeah it seems weird, not what I expected. I expect my expensive chain and reaper to sound better. Then again apple has endless funds to develop audio playback for their specific DAC and yeah maybe you are right; they need to compete with the other music services out there (they also happen to sell Logic,... no conflict there right?) . But I think its something software related that apple must be doing. Maybe its time based manipulation, but I can play both Reaper and iTunes at the same time and it sounds distinguishable, at least to my ears (or I'm crazy) ...so that shouldn't be possible if the master clock is jittering around for a pleasing thing, right? Or maybe they are using a hidden plugin that manipulates time based information, while also releasing the driver to work for Reaper as well? I don't know enough about the techy stuff. But if I was to make the Reaper file sound more like its playing through iTunes, I would reach for a gentle widener or chorus or something as well as EQ.

FWIW, the link I posted allows downloads (its from a SoundonSound shootout) and the file is .aif around 60.4 MB in size.
https://soundcloud.com/soundonsound/...like-this-snow

If anyone else has a MacBookPro and wants to test it out.

Length: 5:42.000
Sample rate: 44100
Channels: 2
Bits/sample: 16 (int)
Total samples: 15,082,200
Blockalign: 4
Datablock start: 512

Last edited by otb; 10-25-2016 at 03:21 PM.
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Old 10-25-2016, 03:15 PM   #11
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Sometimes operating systems have "enhancement" things going on as well. You're on a mac, so i can't speak to that, but at least on windows there might be such things afoot, and if the playback route of iTunes is going through the OS layer, as opposed to reaper going straight to the interface, that could be part of it. But you're going through the on-board soundcard, so I'd guess the route is the same and I don't suppose that's happening.

You can rest assured that any difference you hear isn't due to reaper making some mistake or having a 'sound', as others have explained.

I know mac's can use "aggregate devices" and do resampling-on-the-fly and so forth... you might post a pic of your audio device settings from reaper just so we can be sure it's looking good.

32bit vs 64bit reaper will make no difference in the audio that comes out -- it has nothing to do with the audio processing, just the way the program runs on the CPU (and even from that perspective will hardly matter for you). This is a separate issue completely from "16bit audio" or "32bit float" audio formats, etc.

Have a friend play the file in reaper vs. iTunes, maybe faking some mouse clicks so you can't tell which method is being used, and repeat this test 10 or 15 times, and see if you can identify which is which. Then go here and see if you get a p-value less than .1 or so. (e.g. 10 trials and 6 correct is 37.7% chance of being random guessing.) But make sure playback level is very exactly matched in the two programs: even 1dB of difference can totally sway the results.

In terms of stuttering: any DAW will start to stutter when the computer approaches its limits. Reaper is famously one of the most efficient DAWs (some would say better than any). If you aren't able to record more than a few tracks with a few plugins going there might be some kind of configuration issue with your computer, or a slow disk, etc. Typically the transport bar will flash red when it drops samples during recording (I've long wondered why it isn't S.O.P. with DAWs to pop up a window during/after recording that warns that samples were dropped, when it's aware). If you hear a skip when you're playing audio back and you're worried that it may be "baked in" to the audio, you can always re-play that section and listen again: plyaback skips rarely happen at the same point in time twice, as they are, in a sense, "random", so if the skip is in the same spot, it's in the recorded audio (this can also usually be visually confirmed by zooming in.)

Generally you don't need to worry about non-obvious degradation of the sound due to dropped samples. Dropped samples are almost always clearly audible, and if they aren't audible, they aren't audible, so, hey, no problem. There is no in-between grey area where the sound is just kinda bad but you can't tell immediately. If you were dropping tons of samples inaudibly, then maybe sync would become an issue, but there's no way that would happen without you immediately noticing.

Make sure you aren't running any other software (i.e. "really and truly" close the other programs, even if they have no open windows).

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Old 10-25-2016, 03:32 PM   #12
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Originally Posted by otb View Post
I expect my expensive chain and reaper to sound better.
Wait, what expensive chain? We're comparing reaper vs. itunes to the same output, right?

Quote:
But I think its something software related that apple must be doing.
iTunes may have some hidden 'enhancement' going on, but i'd actually be really surprised, provided it was all turned off in the GUI.

Quote:
so that shouldn't be possible if the master clock is jittering around for a pleasing thing, right?
Not sure what you meant by this, but yeah: if iTunes is playing a song "straight", then it should indeed sound identical to reaper playing it, assuming you didn't do anything to the reaper project defaults, that reaper is using the audio device as you expect (again -- maybe post a pic of the device settings) and you didn't add any monitoring FX, etc etc. Decoding an MP3 or .aif or playing back a WAV is a bitwise-identical process: there is no such thing as variation between 'engines' that would change so much as one bit (ignoring bugs). Reaper is using an internal floating point engine, so there may be nano-scale variation from the conversion to floating point and back, but it's a negligible issue. I'm not aware of any privileged magic that iTunes would be able to work with the audio subsystem to improve it compared to Reaper, but I guess stranger things have happened.

The first thing I'd do is blind test it at matched volume levels with the help of a friend: it's incredible what expectation bias can do in terms of audio perception (and what a dB or two of volume difference can do.)
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Old 10-25-2016, 04:28 PM   #13
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Generally you don't need to worry about "inaudible" degradation of the sound.
I bet. I might have to borrow that for my sig.
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Old 10-25-2016, 04:33 PM   #14
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I bet. I might have to borrow that for my sig.
That makes me realize i could have phrased that better :-). Edited:

"Generally you don't need to worry about non-obvious degradation of the sound due to dropped samples."
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Old 10-25-2016, 04:44 PM   #15
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That makes me realize i could have phrased that better :-). Edited:

"Generally you don't need to worry about non-obvious degradation of the sound due to dropped samples."
Yes but you unintentionally called out what a lot of people unnecessarily stress and argue over.
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Old 10-25-2016, 04:46 PM   #16
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Yes but you unintentionally called out what a lot of people unnecessarily stress and argue over.
Fer sure. :-)
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Old 10-25-2016, 05:38 PM   #17
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I've downloaded the .aif test file...

Sounds fine in REAPER. iTunes is messing with the sound. It's a few db louder...

To check if my suspicion is right, I opened the test file with Audacity. Same level as REAPER.

iTunes, Audacity and REAPER were all set to 0 dB, eg max. output level. Totalmix clearly shows a level difference between iTunes and the rest.

When I have the time, I'll check if iTunes also messes with the spectrum, or other things.
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Old 10-25-2016, 05:41 PM   #18
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I've downloaded the .aif test file...

Sounds fine in REAPER. iTunes is messing with the sound. It's a few db louder...
Did you disable "Sound Check" ? That's the auto-gain feature.
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Old 10-25-2016, 06:03 PM   #19
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"I expect my expensive chain and reaper to sound better."
---Wait, what expensive chain? We're comparing reaper vs. itunes to the same output, right?
I usually use Reaper on a Windows PC, RME fireface 400 as a DAC. Direct from convertors to monitors or headphones. And I'm very accustomed to that sound... I don't ever get that "oh wow, the sound, holy smokes, its glorious, full and round, etc" feeling. Not unless I strap some ear candy on the mix bus and try to make it happen; and usually that stuff sounds so incredibly fake that it fails badly elsewhere. I have some pro analog console channels that I sometimes go through as well, so the chain can upscale to a prettier place. Still, I imagine that if I got a $10,000 DAC and external clock, it would give me that 'ear candy' sound I sometimes want, but without my lame tricks.

what happened when I tried the mac through my monitors, playing some downloaded .wav files back in itunes:. Ear candy, really sweet sounding ADC! Nice, I thought to myself, I can use the Mac for mastering... But then I immediately loaded those files into Reaper (on my same mac) with built-in sound as my audio device, and I'm back to a non-musical kind of sound. Actually kind of what my PC sounds like. Actually A LOT like what my PC sounds like. Hopefully somebody takes a look at this to at least let me know I'm imagining things. I went back and forth a few times. I've waited a few weeks and tried again. I've tried and tried to make myself believe that Reaper is winning on this one, but it just hasn't clicked yet, lol.

side note:
IMO, Reaper with RME is a perfect combination in terms of flatness, although not very 'musical' in terms of beauty. ...sort of like HiDef TV that shows off baseball player's zits and stubble, where maybe the TV's contrast isn't perfect, but the clarity is off the charts.
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Old 10-25-2016, 06:15 PM   #20
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Did you disable "Sound Check" ? That's the auto-gain feature.
Yes, everything is disabled... I tried to load a screen grab but I need to compress it I guess. file size too big.
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Old 10-25-2016, 07:09 PM   #21
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All media player apps play files exactly the same as Reaper here. They'll null with each other.

If you have stuttering playback, it's a resource issue and absolutely the source of corruption of the audio fidelity. Stuttering playback is definitely not normal or acceptable for Reaper running on a Mac!

Check your setup. Activity Monitor and Reaper's performance meter are your friends!

If you're not running live sound or playing MIDI instruments with Reaper, set the block size to 1024 samples for headroom. (Check the box to control this from Reaper. Unchecked means ignore the value entered and let a different app control this. Don't space this one out and leave it set to "who knows?")
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Old 10-25-2016, 08:48 PM   #22
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the clarity is off the charts.
...as it should be, and it will be exactly identical to any other DAW in this context (a vanilla project with an audio file imported).

Re: iTunes: hopefully cyrano or someone else with iTunes can confirm if there is something besides level changes going on.

You may prefer the sound of iTunes if it's mutating the audio somehow, but don't fall into the trap of thinking of it as superior DAC -- first, that would fall in the realm of DSP before the DAC, and for any kind of serious audio work you want the use of monitoring effects to be an intentional act, not something done mysteriously by hidden (unconfigurable) software in the shadows. Regardless of how good iTunes sounds, I wouldn't want any processing it may do within 100 miles of my mixes. :-)

On the other hand, if you like the sound it has (if indeed it has a sound), and you just want a way to play audio back that sounds good (but which is inaccurate), then you don't have to sweat it and can just use iTunes. iTunes through your Fireface may sound even better: almost all laptop audio cards (macs included) aren't very good.

In the meantime, do that blind ABX with a friend (after precisely level-matching)!
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Old 10-25-2016, 10:58 PM   #23
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Did you disable "Sound Check" ? That's the auto-gain feature.
Of course.
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Old 10-25-2016, 11:04 PM   #24
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All media player apps play files exactly the same as Reaper here. They'll null with each other.
I doubt that sincerely, Serr. A while back, when iTunes annoyed me once again, I spent quite some time with a lot of free and demo players. Several of these sounded different. I'll admit these were the audiophile kind, as I was also trying to find a player that supported DSD files.

I ended up liking Songbird best, but that wasn't too stable. So I ended up with iTunes again.
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Old 10-25-2016, 11:47 PM   #25
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I doubt that sincerely, Serr. A while back, when iTunes annoyed me once again, I spent quite some time with a lot of free and demo players. Several of these sounded different. I'll admit these were the audiophile kind, as I was also trying to find a player that supported DSD files.

I ended up liking Songbird best, but that wasn't too stable. So I ended up with iTunes again.
Disclaimer: I don't use Itunes and haven't tested it.

When I tested Songbird, XBMC, & VLC a while back, they nulled with Reaper. I captured the output stream and imported it to Reaper to verify.

Itunes used to (and likely still does) come default with a load of suck buttons turned on in its preferences. Maybe that?

I think that stuff is someone's idea of copy protection. The "If they can't even play it correctly then they can't copy it!" method.


Hmmm...
Might be time for another media player shootout. It's correct to not trust anything.
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Old 10-26-2016, 12:43 AM   #26
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I'm afraid it is time for a shootout...

A 1 kHz, 0 dB test tone is 0 db in REAPER, 0 dB in itunes. All simple one frequency test tones come out as expected.

A -10 db pink noise test tone is -11 db from REAPER, -10 db in iTunes. It's hard to tell, but it seems pink noise is fluctuating a bit more in iTunes and is around half a dB or so louder...

A 0 dB white noise test tone from REAPER shows up with clipping in TotalMix, although the level shown is never over 0 dB. No clipping from iTunes, which is at -1,8 dB.

A -10 dB white noise test tone from REAPER shows up as -10 dB. iTunes shows -9.7 dB.

What's goin' on here?

Is the TotalMix clipping indicator too cautious?

Is there some safety compression/limiting in iTunes? Or Core audio?

Any thoughts on a more reliable test procedure?
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Old 10-26-2016, 01:16 AM   #27
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OK. The clipping comes from Audacity's white noise generator. It's present in the original. I can see 4 clipping indicators in Audacity...

However, played back from REAPER, TotalMix shows 1 of the 4 places where the noise clips. Played back from Audacity or iTunes, it shows no clipping...

It's beginnig to look as if Core audio has a -2.1 dB safety limit to avoid clipping...
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Old 10-26-2016, 10:13 AM   #28
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I did some more listening tests this morning.

- I rendered the 16bit file out of Reaper, turned OFF the wifi and played it back through itunes.
And it sounded like the original file through itunes. So I don't think iTunes is streaming a better version from a server.

- For 30 minutes of listening through the laptop speakers iTunes vs Reaper, I just could not convince myself that they sounded the same. I messed with sound enhancer. Its not that. I messed with compression in reaper, that seemed to help but I think possibly due to brain's perception of volume changes. I even changed themes in Reaper to imperial.

-I discovered that my macbook pro's headphone out is also an optical digital out up to 192Khz (toslink), nice to know!

I think iTunes may be doing something really minute, such as what the expensive clocks do... it would make sense, seeing as how they have billions to hire the best, and the best would know how clocking signature can makes things more enjoyable. (Yeah, I know, not possible, imagination etc... tell that to the pros who actually swear by that stuff, and still part with $10k knowing its probably their imagination ;-)

And after all this, I feel more confident that the Reaper playback is more accurate than iTunes. It sounded more like what a recorded file should sound like while I'm working on it. And it very well could be imagination. It might just be that my brain associates Reaper with "serious work", and itunes as "fun". I've been trying and trying to convince myself that's all that happened here. Kind of depressing to have that much ear/brain disconnect, if thats all it is.

The good news though is that when I reach a wall where things just aren't getting any better, I can load it into iTunes and see if I like it better.
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Old 10-26-2016, 10:47 AM   #29
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Could it be iTunes already has some sort of EBU128 like scheme?
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Old 10-26-2016, 11:22 AM   #30
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Cyrano -- perhaps the test we need to do is reaper/iTunes -> mac headphones analog out -> RME analog in -> Reaper. Then in Reaper you can compare levels and do FFTs, etc.

What exactly were you monitoring with TotalMix? I.e. what was your test chain?

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And it very well could be imagination.
I'm waiting for the blind ABX results. Collaborate with the tester to make sure both are exactly the same volume, and find out the truth of what you're hearing, and you won't have to spend all this time wondering and changing themes and so on. :-)

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Kind of depressing to have that much ear/brain disconnect, if thats all it is.
It may well be a real thing you're hearing, but the ear/brain disconnect is legend, so it's worth ruling it out.
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Old 10-26-2016, 12:30 PM   #31
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Cyrano -- perhaps the test we need to do is reaper/iTunes -> mac headphones analog out -> RME analog in -> Reaper. Then in Reaper you can compare levels and do FFTs, etc.

What exactly were you monitoring with TotalMix? I.e. what was your test chain?
It was a very simple test. Playback the same files from REAPER, iTunes and Audacity. Check levels in TotalMix.

That's why I started out with constant one-frequency tones. As these showed no surprises, I moved on to white/pink noise. A bit harder to read levels in TotalMix, as these jump around a bit.

Interface is a FF400.

Music is of course a pita to check levels...

And I can't seem to concoct a different test setup to see what itunes does to dynamic signals. I've considered a sweep. But as that is constant level again, I expect it to show no surprises either.

Loopback recording and null test with music?
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Old 10-26-2016, 12:46 PM   #32
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It was a very simple test. Playback the same files from REAPER, iTunes and Audacity. Check levels in TotalMix.
Checking the output levels in TotalMix? I'm not sure that would be reliable in terms of 0 dBFS peak test signals... afaik reaper is sending fixed point data to the interface (someone correct me if wrong?), which of course can't clip, so the clip indicator is going to need to be "guessing" in some heuristic way about when the audio has clipped?

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And I can't seem to concoct a different test setup to see what itunes does to dynamic signals.
What did you think of my suggestion to do reaper/iTunes -> mac headphones analog out -> RME analog in -> Reaper ?

The first thing I'd do is render 30s of white noise at like -3 dBFS. I'd play it out of reaper, and record the loopbacked-though-the-RME result. Then I'd play it out of iTunes and record the result. Then in reaper I'd run an "infinite window" FFT on it, plus whatever other analysis (peak, peak RMS, etc), and compare. Then I'd repeat with a music track.

I like your guess of iTunes possibly having near-0dBFS limiting going on.

If I can get ahold of a mac i'll do this myself.
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Old 10-26-2016, 12:48 PM   #33
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Another test idea. I generated a lot of harmonic tones, starting with 440 Hz. Mono.

iTunes and Audacity show -26.2 dB
REAPER shows -26.3 dB, both from the media bay and from a track.

A minute difference, but a difference. So I played around with panning and levels and generated a stereo file. The difference between REAPER and itunes grows to 0.7 dB for the left channel and 0.4 dB for the right channel. But this time, REAPER is louder.

??
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Old 10-26-2016, 12:57 PM   #34
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A while ago i've made test playing same music trough same synth preset on reaper and cubase, and the difference was hearable. In fact, all people who noticed it said that cubase sounds better, sharper and clearer. Tracks were named AB for obviues reasons. Pan law was the same, as was the output volume. you can listen to it yourself if you look up that thread.

Now reaper also sounds to me uiter then everything else. But after render apparently is very loud!

However, with midi, block size does make a difference, but still precision is better in cubase. So THE ENGINES make the difference in processing the information that it is then turned in to sound.
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Old 10-26-2016, 01:07 PM   #35
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Checking the output levels in TotalMix? I'm not sure that would be reliable in terms of 0 dBFS peak test signals... afaik reaper is sending fixed point data to the interface (someone correct me if wrong?), which of course can't clip, so the clip indicator is going to need to be "guessing" in some heuristic way about when the audio has clipped?
The clipping indicator in TotalMix is reliable, accurate, but it keeps it on the safe side. I recently had to calibrate meters on a digital mixer after repair, so I'm reasonably sure. I kept the LED meters on the mixer about a half dB under the meter in TM and that worked out allright.

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What did you think of my suggestion to do reaper/iTunes -> mac headphones analog out -> RME analog in -> Reaper ?
I had considered that. Unfortunately, my headphones out is a bit damaged and a bit noisy on one channel. These 3,5 mm jacks aren't very solid.

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The first thing I'd do is render 30s of white noise at like -3 dBFS. I'd play it out of reaper, and record the loopbacked-though-the-RME result. Then I'd play it out of iTunes and record the result. Then in reaper I'd run an "infinite window" FFT on it, plus whatever other analysis (peak, peak RMS, etc), and compare. Then I'd repeat with a music track.
Sounds good.

Now I think of it, I can of course loopback record through the RME. Should have tought about that sooner...

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I like your guess of iTunes possibly having near-0dBFS limiting going on.

If I can get ahold of a mac i'll do this myself.
That would be great!

Of course, if you have itunes on a Windows machine, it would be interesting to see if we get similar results.
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Old 10-26-2016, 01:11 PM   #36
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The clipping indicator in TotalMix is reliable, accurate,
Sure, but assuming that it's working off fixed-point data, it can't detect a true a "clip" because there is no such thing, so it has to guess at where a clip might have happened, and if you're feeding it 0 dBFS white noise, there are going to be a lot of places that look like the audio clipped, when it actually didn't. Or, afaik, where a rounding error might push it over, etc.

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Now I think of it, I can of course loopback record through the RME. Should have tought about that sooner...
Yeah, definitely worth a test -- but if nothing is found there is still the headphone output to test to really match what the OP was doing.

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Of course, if you have itunes on a Windows machine, it would be interesting to see if we get similar results.
Yeah... i have kind of a religious objection to installing apple products though... too many pains in the ass in the past. :-) Maybe i'll do it in a VM.
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Old 10-26-2016, 01:17 PM   #37
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However, with midi, block size does make a difference, but still precision is better in cubase. So THE ENGINES make the difference in processing the information that it is then turned in to sound.
I haven't a clue about MIDI.

But playing back digital audio, I'd expect the audio engine not to do anything, except send the data to the output?

I would expect rounding errors of 0.1 dB at most, going from 64 bit floating to 16 bit.
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Old 10-26-2016, 01:18 PM   #38
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Originally Posted by cyrano View Post

I would expect rounding errors of 0.1 dB at most, going from 64 bit floating to 16 bit.
This may shed some light on Miks claim...

http://forum.cockos.com/showthread.php?t=174042
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Old 10-26-2016, 01:22 PM   #39
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Yeah... i have kind of a religious objection to installing apple products though... too many pains in the ass in the past. :-) Maybe i'll do it in a VM.
Seems wise.

Does itunes on WIndows still require Quicktime?

It's one of the biggest security holes ever on Windows, since Apple refuses to update several MS DLL's that dat back to the dinosaurs. Updates are available, but Apple shows no interest at all...

Besides that, you could test against Media player. I suppose that's installed by default and I expect that to show some funny results too. Maybe add foobar for reference?

What throws me off with my tests, is that with music, Audacity and REAPER are alike and itunes is different. With the harmonics test, Audacity and itunes are alike and REAPER is different.

Need to think about that...
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Old 10-26-2016, 01:25 PM   #40
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This may shed some light on Miks claim...

http://forum.cockos.com/showthread.php?t=174042
Yeah, Karbo. Thanks. I remember that thread.

I'm gonna set a test up with digital loopback over ADAT. However, I'm painting a rack and need to apply a new layer every 3 hours. If too late, I need to wait 6 weeks (Hammerite paint)...

So it might take a while
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