OK. I checked some plugs on the weekend and it seems to me that the RTAS versions sound better than the AU ones (more accurate, more discreet, more on-target)...

Can anyone else confirm this?

I am mixing on ProTools and Logic Pro...

Quote Athanasios C. Paschalis:

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Can anyone else confirm this?

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No. Companies that offer both RTAS and AU versions of their plugins will be using the exact same engine and processing code, just the wrapper/framework code will be different, and this will have no affect on the sound.

The only issue will be on TDM systems where the transfer is a fixed point value. You MIGHT clip the plugins of the RTAS version and that may make RTAS sound worse/louder (the two terms being apparently synonymous;)).

Other than that - any differences will be down to things being programmed differently. There is no static or processing reason for them to be different.

Can it be then that the audio engine of ProTools is different/better than that of Logic Pro?

DAWs sound the same, all things being equal. It's possible that you have tiny differences in settings between Logic and PT. Eg whatever the pan law is set to by default might affect how you perceive a mix/stereo source. The only differences (assuming comparing 24/32/64-bit versions with like equivalents) I've observed in sound between DAWs (other than the bundled plug-ins obviously!) is how they sum when you overload the master bus — ie they're all bad, but in different ways. So you shouldn't be doing that in a DAW in any case. As someone else said, RTAS, VST, AU etc will all employ exactly the same signal-processing code.

Quote Athanasios C. Paschalis:

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Can it be then that the audio engine of ProTools is different/better than that of Logic Pro?

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The TDM versions of PT are different, as they use a 48 bit fixed point system. The native versions of ProTools from 9 onwards finally switched over, after many years, to the same 32-bit floating point implementation as all the other native DAWs.

Quote Athanasios C. Paschalis:

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Can it be then that the audio engine of ProTools is different/better than that of Logic Pro?

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Depends what you mean. The summing side is all the same (since there really is only one way of doing it). However there are other things to consider - plugins reporting delay correctly, compensation working on complex networks, clipping fixed point busses, the ASIO/audio driver and how it integrates with the DAW and interface. On the pure digital side - then no; they're all the same.

Plugs should sound the same.

Probably different pan law settings are what you hear.



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G-Dub
Studio G-fx 15inch quad-core i7 Macbook Pro Logic913

In a discussion with AVID engineers on why RTAS instruments are so inefficient, they basically said that choices were made with RTAS to make it perform a certain way for audio processing, and that those choices were part of what made the format perform less well as a VI. I don't know whether that would affect sound or just efficiency.

Logic does sound worse than other DAW's when you get to the limits of your machine, because Apple changed it so that it ignores a certain number of dropped samples before throwing up an error. I'd imagine that you're not at that point though.

You're not the only person to make this observation. A lot of people have found that moving from Logic to Pro Tools sounds better. Although despite that it seems extremely difficult to demonstrate any difference. I wouldn't be surprised if this is something to do with the screen layout or colours affecting our perception. Colour and sound are closely linked and I wonder if something like that is going on.

J

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www.jackruston.com

Thanks everyone for your replies.

I haven't pan anything yet to hear differences due to the pan law.

Quote Jack Ruston:

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I'd imagine that you're not at that point though.

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You are right. I am not at that point yet.

Quote Jack Ruston:

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I wouldn't be surprised if this is something to do with the screen layout or colours affecting our perception.

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I would.

Quote Jack Ruston:

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Colour and sound are closely linked and I wonder if something like that is going on.

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I find that unlikely though I see your point. I often turn off the screen when I am auditioning the mix on the final stages. I'll mix on ProTools anyway...