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[Mike48]

MC has some great DSP features. I use it for digital crossover and to fix a bass bump, and am considering using it for DRC.

Any chance of implementing "Blumlein shuffling"?  This old technique is reported to improve realism of stereo recordings, particularly those made by panpotting mono signals (many jazz and pop recordings). It seems like the sort of thing that might make a difference and that might be fun to implement.

For example:  http://www.audiosignal.co.uk/Resources/Stereo_shuffling_A4.pdf

Thanks for considering it!

Mike

[mojave]

It is already implemented in DSP Studio. Use Effects > Surround Field. Make sure you set the other effects to (none).

[Mike48]

When I mentioned this in another online forum, I got this answer:

Note that Blumlein shuffling seems to mean different things in different contexts. I think what J River is doing is increasing the gain on the stereo difference signal (the S in M + S) in order to increase apparent image width. On the other hand, what is usually meant by shuffling on this forum seems to be a modern version of the old EMI technique, which is to introduce crosstalk (reduce channel separation) as frequency increases. The latter is supposed to produce more focused and stable phantom stereo images.

So, I wonder if anyone will tell me, what is MC doing behind the scenes when "Surround Field" is used?  Is it just increasing S, or is it frequency-dependent separation with more separation in the bass, as described in the link of the original post?

Thanks!

[mojave]

JRiver isn't going to say exactly what is happening behind the scenes. See this thread for a little more info:
Effects: Surround Field, what does it do exactly?

[sorepinky]

I've been using the Surround Field effect with a level of "Pronounced".  It's pretty awesome, but I have noticed in certain music that the left channel mutes periodically.  I have no other effects in use, but do have some parametric EQ for the bass set in DSP Studio.

Is that a natural side-effect, or something that could be looked into?

[mwillems]

I've been using the Surround Field effect with a level of "Pronounced".  It's pretty awesome, but I have noticed in certain music that the left channel mutes periodically.  I have no other effects in use, but do have some parametric EQ for the bass set in DSP Studio.

Is that a natural side-effect, or something that could be looked into?

If you're adding boost with PEQ, and not reducing the overall digital volume to compensate you may be driving your system into digital clipping.  JRiver's clip protection deals with clipping by briefly reducing the volume (to avoid clipping), but that should apply to all channels not just the left.  It may have some unusual interaction with the surround field effect?

Make sure you don't have unoffset boost in your EQ, and verify that the problem still persists.

[sorepinky]

There is no boost in my PEQ table as it would be cancelled by the room anyway.  I only use it to tame a 40Hz room mode (-9dB Q=2.5).

When using the highest setting in Surround Field "Maximum Enhancement" (even with no PEQ) I do see the clip protection come in occasionally, but it's only a dB or so and no audible muting takes place.  The left channel intermittent muting which I refer to is not happening during loud passages anyway.  It seems unrelated.  My guess is that there's something awry in the Surround Field algorithms and it can only be a guess as I am not privy to them.  It seems though that whatever is going on in "Surround Field", it spectrally colours the sound using L/R sum/difference algoritms with more "summing" going on (invoking occasional clip protection) with the higher settings.  A different (allegedly non-colouring) approach seems to be the subject of Nokia's USP 6,928,168 in which only delay is used with cross-talk instead of L/R frequency-dependent amplitude sum/differences.

It's a minefield of patents out there and it's hardly any wonder that JRiver seems to play their cards close to the chest on this stuff.  I would too.

This is no big deal as it only happens on some albums and rarely, but it actually sounds like the left speaker is switched completely off then back on again.  And it only ever happens with the Surround Field in use.  Maybe it's a natural side-effect.

[mwillems]

This is no big deal as it only happens on some albums and rarely, but it actually sounds like the left speaker is switched completely off then back on again.  And it only ever happens with the Surround Field in use.  Maybe it's a natural side-effect.

That is odd, and it does sound like a bug of sorts.  If you wanted to run it to ground, I'd advise posting a concise description in one of the build threads, with an offer to provide a sample clip that shows the problem.  If you can provide a sample and they can reproduce it, they'll probably fix it (if it's fixable).

[sorepinky]

Haven't been able to reproduce it, so I'll put it down to either a glitch in my own system or an MC20 update in the interim.  In the meantime I got tired of the effect and turned it off as it had pianos dancing around from left to right speakers depending on what notes were played.  It's basically a fun effect for some music, but not hi-fi.  Cheers.