Major db difference between Rip and other programs

Discuss Rip, an open source accurate CD audio extractor.
rydenfan
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Major db difference between Rip and other programs

Post by rydenfan » Thu Jul 09, 2009 3:25 am

So tonight I downloaded and tested rip. I extracted the same album three times: once with rip, once with itunes, and once with max. It was very interesting to say the least. Rip is -4 db down from both itunes and max. itunes and max are either identical or within .5db of one another but rip is considerably off from the other two. Is there any explanation as to why this would be?

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sbooth
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Re: Major db difference between Rip and other programs

Post by sbooth » Thu Jul 09, 2009 5:35 am

What do you mean when you say down by -4 dB? What format did you extract to and how did you determine the -4 dB? Is this a replaygain issue perhaps?

rydenfan
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Re: Major db difference between Rip and other programs

Post by rydenfan » Thu Jul 09, 2009 1:43 pm

for RIP and itunes I extracted them in AIFF. Since MAX does not support metadata for AIFF, I extracted it in FLAC and then used XLD to convert it to AIFF. I then played the same track from each and the RIP was 4 db down on my SPL meter compared to the itunes and MAX/XLD version. I do not use replaygain but will double check to make sure.

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sbooth
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Re: Major db difference between Rip and other programs

Post by sbooth » Thu Jul 09, 2009 11:34 pm

A good way to compare the files would be to set the drive's offset to 0 in Rip, then extract a track using both Rip and Max to FLAC. Then compare the MD5 checksums in the FLAC files- they should be identical. This way the player is taken out of the picture.

rydenfan
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Re: Major db difference between Rip and other programs

Post by rydenfan » Wed Jul 15, 2009 3:37 pm

I tried tried ripping a few different discs and the same problem occurs everyt time. The extraction done with RIP plays -4 db as compared to MAX or the itunes ripper. Has anyone else tried this?

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sbooth
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Re: Major db difference between Rip and other programs

Post by sbooth » Wed Jul 15, 2009 4:02 pm

Did you try setting the read offset to 0 and comparing the file's MD5 sums as I suggested above? I am willing to bet they are identical and the difference is player-applied replay gain.

rydenfan
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Re: Major db difference between Rip and other programs

Post by rydenfan » Wed Jul 15, 2009 4:06 pm

I have not but I will try that.

Why would itunes apply replay gain to the RIP copy but not the MAX? That does not make a lot of sense to me. I apologize if I am not understanding something. All I know is that when I play any disc that I extracted with RIP the volume is considerably lower than it is when using MAX or itunes ripper.

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sbooth
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Re: Major db difference between Rip and other programs

Post by sbooth » Wed Jul 15, 2009 6:00 pm

Rip calculates and stores the replay gain for tracks and albums, but Max does not.

rydenfan
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Re: Major db difference between Rip and other programs

Post by rydenfan » Wed Jul 15, 2009 6:23 pm

sbooth wrote:Rip calculates and stores the replay gain for tracks and albums, but Max does not.
Is there any way to turn this feature off? When I import the album into itunes it shows the volume for the album at almost 50% down. I then have to adjust it back up to be at zero.

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Re: Major db difference between Rip and other programs

Post by ted_b » Wed Jul 15, 2009 6:29 pm

I am new to MAC but know computer audio well enough. i do not use Realplay gain (in foobar, anywhere). i ripped a test cd with iTunes, XLD and RIP. I love the simplicity of the RIp interface but not the fact that it rips at 50% volume (according to "options" in iTunes metadata pullup). So, in fact, Rydenfan and i have the exact same issue. i didn't ask for replaygain, nor would I think that any hidden or accuraterip-based replaygain settings (?) would be at 50% volume?? What's going on? It's unusable at this point, as i'm not interested in pumping the gain back up artificially. i have a very hirez system and that idea is not going to fly. please advise
Thx
Ted

rydenfan
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Re: Major db difference between Rip and other programs

Post by rydenfan » Fri Jul 17, 2009 2:20 am

Is there no answer for our issue?

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sbooth
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Re: Major db difference between Rip and other programs

Post by sbooth » Fri Jul 17, 2009 5:10 am

I would have thought that disabling sound check in iTunes would turn off the per-track volume adjustments, but in my quick test it didn't. I don't use iTunes extensively so I may be misunderstanding what exactly sound check does.

I will add an option to Rip that will allow users to specify whether or not RG is calculated.

In the meantime, you can always rip to Apple Lossless which doesn't contain the embedded RG info. I'm a bit surprised iTunes doesn't have a way to enable/disable relative volume control.

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disneymike
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Re: Major db difference between Rip and other programs

Post by disneymike » Fri Jul 17, 2009 9:16 am

I looked at my AIFF files ripped using Rip and they indeed play at 50% volume in iTunes on my system as well. Using Peak Pro 6 they seem to play at 100%. I've ripped quite a few CDs using Rip. Since it sounds like the audio is recorded fine and the replay gain is simply an embedded number in the file, is there some way to batch correct the replay gain on existing AIFFs instead of ripping them again using a newer version of Rip which has an option to turn off the setting of replay gain?

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sbooth
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Re: Major db difference between Rip and other programs

Post by sbooth » Fri Jul 17, 2009 4:21 pm

The RG information is stored in RVA2 frames in an 'id3 ' chunk in the AIFFs. There might be an AppleScript over at dougscripts for removing these- or some ID3 editors might work as well.

This honestly seems to be a bit of a shortcoming in iTunes (the inability to disable RG/relative volume adjustments), although iTunes isn't designed to interoperate with anything else- everything else is supposed to be designed to interoperate with iTunes.

rydenfan
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Re: Major db difference between Rip and other programs

Post by rydenfan » Fri Jul 17, 2009 9:44 pm

MAX never had this issue so why now is it a problem? I would think it should be easy enough to remove replay gain from RIP. I really like your products very much but this is a deal breaker for me, and likely many others. I love your interface but will have to continue to use an alternative ripper until this issue is solved. Many people who have computer based audio use itunes for their interface, most likely the majority, so hopefully this can get worked out.

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