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This is the discussion thread for the "Mac Corner" SPEC versions viewtopic.php?f=8&t=216&p=1702#p1702

Z.

Oh Yeah ! Oh Yeah ! Oh Yeah !

I spent a lot of time slogging around the internet looking for stuff we take for granted on windows, e.g. EAC, foobar, imgburn, not to mention a DTS encoder.

Here's what I ended up with to do the job:

To rip, tag, split, and make cue files: XLD (GUI version): http://wiki.hydrogenaudio.org/index.php?title=XLD

To burn (from wave/cue files) LiquidCD: http://www.maconnect.ch/index.php?page=&lang=en

LiquidCD can also make cue files, however that feature is currently broken. The author promises to fix it in the next release.

There are other burners, but none I found, including "Toast", would burn a wave/cue.

Vortex Surround Encoder: http://im-research.com/products/

OK here's the workflow:

1a) Starting from a CD, rip to single wave and cue file with XLD.

1b) Starting from individual .flac convert to a single wave and cue file with XLD.

2) TrackTime and Spec on the mac. Pretty much identical to the windows version. Only difference is the free mastering and limiter VSTs are replaced by free apple AU plugins.

3) Encode with VSE (vortex Surround Encoder)

4) Make a copy of the cue file and edit as usual to point to the DTS wave file.

5) Load Cue file into LiquidCD and burn.

That's it.

Oh, I guess I sound mention playback. Assuming a digital out on your mac or air tunes express, you can play dts waves in itunes. I haven't looked for other players that would do the dts decoding "on board", but I guess VLC would be the best bet.

For the gory details of iTunes and DTS see the guide in the wiki under general methods.

FYI VLC works fine for dts wave playback. Can't do cue files like foobar however.

If you want to generate individual wave files from the dts encoded album dts file you can use XLD to split.

This is a supplement to the SPEC 4.3 guide

What's new in Spec 4.4

ArcTan works by using the relative magnitudes of the Left and Right stereo frequency bins (spectral domain) to "steer" the audio in the surround filed. If the Left had say -3 db in the 500 hz bin and right had 0 db, then ArcTan would pan the output (@500 hz) towards the right (quite a bit of math, based on width controls etc., to get the exact angle).

But in the spectral domain we also have the frequency data. In Plogue's "Phase Vocoder" FFT for each bin we also have values for the frequencies, and they can be different for left and right, so the addition in ArcTan, SPEC 4.4 is to "steer" the audio based on a combination of magnitude ratios and frequency ratios. There are two extra controls:

A slider from 0 to 1, where one is steering my magnitude only (as before), and 0 where steering is by frequency only. Seems like about 0.8 is the sweet spot.

A drop down where you can decide how to add the frequency steering to the magnitude steering. If everybody likes just one or two of these we can eliminate the others. Basically they are higher frequencies ratios get pushed toward the center, away from the center, to the left, or to the right.

Here are some diagrams:



...

Besides the new ArcTan there's an input selector, bass routing built into ArcTan for easier PTA, a new version of ZPlayer, plugin version labels at the bottom of the group controls, a meter connection for Zmon (mainly for phase/coherency meters), and Zmon is now post limiters.

What's new in Zag 2.0

A couple of bug fixes (oops!) and a new "peak capture" feature. During the "measure levels" step, Zag will save 6 clips of all six channels, one clip for the highest peek in the entire conversion, for each channel. As you are adjusting the settings in Zag between "measure levels" and "apply gains" you can play back those clips and see how they sound and how they look in the limiter GUIs etc.

You do this via the drop down that has "measure levels" and "apply gains" on it. There are also more controls you can pop open, as you will see, but these are not strictly needed to get the basic functionality.

Couple of caveats: 1) The clips don't get saved with your layout. If you quit or otherwise blow up Plogue they're gone, unless you go through the whole "measure levels" step again.

2) (And this is hard to explain) These clips represent the six sections of music with the highest peeks in the entire conversion, before ZAG adjusts gains, so, because of track to track normalization etc., they may not be the highest peeks after Zag.

The whole point of this is if you're trying to crank up the output level of Zag in order to let the limiters soft clip transients, while brining your overall volume up. before Zag 2.0 you had to search around for loud sections and take your best shot. No you can quickly see and hear the loudest peaks coming out of Spec.

Cheers,
Z

Bass Routing is another new feature in SPEC 4.4.

Here some info on what that is and how it is different than "Bass Management" in an HT:

This is what your HT should do (if you have a satellite/sub system):



It does two things:

1) It has a highpass filter (one half of the crossover) between the 5.0 channels and your satellites.

2) It sums the 5.0 channels with the LFE (LFE at +10db to make the LFE the same volume as the 5 other channels added together) and sends it through a lowpass filter (the other half of the crossover) on to your subwoofer.

ArcTan and SLICE are 5.0. They don't do anything with LFE. LFE happens in the Time Domain, connected between SPECs LI RI ins and the LFE out.

Now, inside ArcTan and SLICE, we are doing something sort of like bass management, except instead of routing the stuff from the low pass filter to the sub or LFE we route it to some of the other speakers.

Bass routing settings (spectral domain):
5.0 No bass routing

4.0 The frequencies below the XOver point is removed from the center channel and half of it (volume wise) is added to LF and half to RF.

3.0 The frequencies below the XOver point are removed from LS and added to LF, and from RS and added to RF. No change to C.

2.0 The frequencies below the XOver point are removed from all channels. The frequencies below the XOver from LI and RI are added to LF and RF respectively.

1.0 The frequencies below the XOver point are removed from LS, RS, LF, and RF, and added to C.

Now if the bass routing XOver freq is set less than or equal to the crossover freq. of your bass management rig bass routing won't do anything because you bass management will be putting everything in you subwoofer at that point.

The idea of bass routing is that if sounds below 200 hz don't add directionality (i.e. separation) then let's not send them to the 5.0 speakers at all. This idea came from a "dolby of video" post, where thy removed signals that didn't have "depth" information.

Another part of the theory is that if we take all that sound that doesn't add to directionality, and put it in the subwoofer, we have less chance of cancellation in the room and should end up with tighter bass.

So, why not just raise your bass management crossover point to 200 Hz? Well I guess you could, but a) your subwoofer may not be designed for that b) if your satellites can produce lower freq. than 200 Hz my guess is that for stereo, movies, etc. you're going to want a lower crossover point. Somewhere between 80 and 120 Hz.

So this Spectral Bass Routing is really only has a working range between 200 Hz and your HT Bass Management Crossover freq.

Hmm, maybe I should add a control that cuts out the highs, so you can hear only the low freq. stuff so you know what you are routing and it be easier to tell if it's going to help with separation or not?

Anyway, let's come back to LFE. The LFE in SPEC 4.2 and above is as you know three filters, connected in series between the sum of the LI RI inputs and the LFE output of SPEC. Lowpass filter, peaking or bandpass filter, and highpass or subsonic filter. If you use LFE in SPEC that signal gets passed along to your bass management in your HT and sent on to the sub as described above.

Z

Zplayer is red, and zag isn't showing at all.

I got those working, but the interface seems kind of "locked". I can double click on a bidule and see the settings, but I cannot move wires or add more bidules (no sound)

Please try the following.

1) Turn processing off (right most button at top of Plogue).

2) Open Plogue Bidule preferences and the DSP tab.

3) Set the following:

Sample Size: 44100HZ
Buffer Size: 4096
FFT Size: 8192
FFT Overlap: 8
Higher Precision FFT: checked.

4) Apply the settings.

If you can not unfreeze Plogue, start it without loading SPEC and make the above changes, then load SPEC.

Z