Can't get ambisonic to work with Logic

[ConcertinaChap]

Tearing my hair out here (not advised when it starts to thin) ...

The idea before I actually buy a Rode NT-SF1 is to experiment with the plugin by importing some of the tracks that are out there on the web. So I set Logic up for surround and created a quadrophonic track and imported one of Rode's example polywav files. You can see from this picture that Logic is only showing two tracks in the file rather than 4:



And of course when I play there's only two inputs with data in the plugin:



I've tried this with several files from different sites (and even with the Surroundzone 2 plugin) and clearly I'm missing something stupid, but what? There's surprisingly little info about Logic and ambisonics on the web. Anybody got any ideas?

TIA.

CC

PS incidentally a strange thing happens if I set the output format on the plugin to 5.1. All four inputs on the plugin are shown as receiving data but Y and Z are the same as X and Y only delayed by 2 or 3 seconds.

PPS opening the files in Audacity shows that they are indeed four track polywavs.

[Sam Inglis]

Logic does my head in at the best of times, but what happens if you actually record onto your quad track -- do you get a four-channel file then?

[ConcertinaChap]

I haven't tried recording because I don't have an ambi mic yet. I could try sticking four random mics in and seeing if I got four tracks, is that what you're thinking? I'll try that later if one of the Logic wizards don't come up with something.

Cheers,

CC

[Sam Inglis]

Well, seems to me the obvious possibilities are (a) that Logic somehow isn't recognising the file format, or (b) that what you've created is not actually a surround track. So you could test (b) just by recording on it for a few seconds even with nothing connected to the input, to see whether you then get four waveforms or only two.

Is it possible that Logic doesn't actually support surround tracks, only buses? That was the way Nuendo used to work IIRC.

[Kwackman]

Non Logic user here, so ideas may be useless!

In the first picture, the "Input" tab is highlighted, showing 4 speakers in Quadraphonic mode.
If you click on the "Output" tab, is it similar?

In the second picture, the right side of the plug-in window the "output" tab shows "Stereo", can that be made a surround output?

[Con Sord]

I couldn't get the SoundField SurroundZone 2 plugin to work in Logic (with the SPS200) either, I don't think Logic supports the 4 channel track A/B format; it does support 5.1.

The solution was to use Reaper where you can route channels (easily) and bounce to correct surround format, for Logic if required. It was where my conversion to Reaper began....

[ConcertinaChap]

So you could test (b) just by recording on it for a few seconds even with nothing connected to the input, to see whether you then get four waveforms or only two.

I'll give that a whirl now.

In the second picture, the right side of the plug-in window the "output" tab shows "Stereo", can that be made a surround output?

Tried that. That's when I noticed that strange business I described in the PS. Should be able to output stereo anyway.

The solution was to use Reaper where you can route channels (easily) and bounce to correct surround format, for Logic if required.

That's my backup plane. I've already downloaded Reaper ready.

Thanks gents.

CC

[Drew Stephenson]

That's my backup plane.

Strewth, I knew you Mac users had an extra bob or two but...

[ConcertinaChap]

[Matt Houghton]

That's my backup plane.

Strewth, I knew you Mac users had an extra bob or two but...

But... they actually cost less than most of the adapters you need to hook anything up to a modern Mac.

[ConcertinaChap]

Well that is interesting. Pressing record without input didn't tell me very much, TBH, so I stuck 4 mics on and pressed record and lo! and behold! all 4 meters on the channel started bouncing around a treat. At the end of recording the region still showed just two tracks (which is why recording without mics didn't help) but look what happened on playback via the plugin:



In fact everything was working exactly as it should. So I'd guess there is a problem importing ambisonic files but recording and using them afterwards is fine. This means I can go ahead and buy an NT-SF1 in some certainty that I can use it in the studio.

However, I'm still left with a concern. The main purpose I have for the thing is onsite recording and for that I was considering buying a Zoom F4 since the current version of the firmware apparently knows all about ambisonics. If importing is failing then that rather cuts away at the basis of that.

So the question is no longer why won't ambisonics work on Logic but why is importing an ambisonic file failing. That's a much more specific problem so thanks all. I'm still open to suggestions on how to fix this one, mind!

Cheers,

CC

[Wonks]

Now you've created two x two lanes that work, can you drag the ambisonic files on to them?

[ConcertinaChap]

I tried that, following a suggestion I read elsewhere. Same as before, sadly. Another lead that has softly and suddenly vanished away is Wave Agent from Sound Devices, which is supposed to split and combine poly wav files in all sorts of useful ways. Unfortunately it refused to install.

CC

[zenguitar]

There are a lot of Logic users out there. If you haven't already, it might be worth engaging with Röde support about your problems. You never know, they might already have come across this problem and have a resolution to hand.

Andy

[ConcertinaChap]

Yes, worth a try, I think. Meanwhile I'm going to buy an NT-SF1 anyway. The reassurance that I can use it in the studio is enough to justify it plus if necessary I can cobble together something for live recording based around our Macbook Air despite my dislike for using computers for this.

Any further developments I'll post. If anyone has further ideas I'd still welcome them.

CC

[Wonks]

I can only think that there must be some encoding difference in your external samples that Logic doesn't like or isn't fully compatible with the plug-in.

[ConcertinaChap]

The samples were mostly downloaded from Rode's website so the plugin shouldn't be the issue, and the issue also occurred with the Surroundzone plugin (the equivalent from Soundfield) so on balance I'd say the fickle finger of blame is pointing mostly in Logic's direction. We shall see.

CC

[Wonks]

I have just realised that this is the insane world of the Mac forum, where I have no right or wish to be.

[ConcertinaChap]

[Wonks]

[Dave B]

This is all fascinating. I'm not sure that you want quad at all - surely you want to provide the Rode plugin with Ambisonic A or B format files? These would effectively be a combined stream of 4 mono files - so the trick here is to find a way of turning your 4 mono files into ambisonic format files. Then, you can send that through to the Rode plugin to process it into a stereo file.

So you are looking at quad as it is a 4 channel file format? Is that valid to feed into the Rode plugin? It says it requires A or B format input.. can your 'quad' format feed that?

Confused.

I'd also vote for "email Rode and ask how to turn mono files into A or B format files for processing in Logic". They must know of a process and, as they are supplying a plugin, must have a workflow to follow...

[Sam Inglis]

I don't think there is a specific Ambisonic file format, is there? Certainly to use these plug-ins in Pro Tools you need to have your audio on a standard Quad track.

[ConcertinaChap]

And the same in Logic. What the plugin is expecting to see is 4 streams of audio data within the one channel, i.e. a quadrophonic channel. It will treat that as ambisonic data (A or B format as you tell it).

When you record from an ambisonic mic in Logic you need to enable surround in preferences, then create a quad track (which Logic helpfully assigns to the first 4 inputs on your interface), plug in the mic and record. This creates a polywav file. I've tried this out in principle with 4 unrelated mics and the plugin works with those. The NT-SF1 arrives sometime today and I'll try it out for real then.

My concern is that when you import a polywav file instead of creating a fresh one by recording it all seems to go belly up. I've done a lot of googling on this and drawn a blank; I guess I'll try Rode support when I've had a play with the mic. At least I've managed to get Wave Agent installed so that gives me another line of attack on the problem.

CC

[ConcertinaChap]

Well, the mic's arrived and ... it works fine with Logic. I rotated the mic slowly in my hands while talking rubbish into it and then played back through the Soundfield by Rode plugin specifying a stereo output. I was quite shocked how effectively I could change the polar pattern of the virtual mic and focus in on different points in the ring of space around the physical mic. The spectral effect that shows the current directions sound is being received from is also effective as well as pretty, you miss it with the Surroundzone 2 plugin which doesn't have an equivalent. I'm pretty chuffed as it means I can use this mic exactly as I'd hoped.

Next stop, then, why can't I import ambisonic files into Logic?

CC

[ConcertinaChap]

It gets stranger. I treated the audio data file created during my test above as a physical data file and imported it into a new Logic project. It worked fine. I thought this might be because the Logic file was aiff whereas the sample files were all wavs so I tried converting one of the wavs to aiff using Audacity. Still the same problem on import. It seems that Logic is happy with poly files it makes itself and positively unhappy about anybody else's. Sigh.

CC