clipping sound on new iMac when Logix X is running

I just spoke with Focusrite headquarters in London over the phone and they replied that it was a well known issue by know. This is a high priority problem that they are working on solving together with apple and hopefully other manufacturers do the same.

I just updated Mavericks to the just released version but it didn't fix the problem.

Yes Cerstrand, I have my FD split and all is well. There is no performace change, the only difference is that the SSD must be manualy managed since there is no FD software juggling data.

This must be a temp fix since we did pay extra for FDs.

That is good to hear. What does that manual manage involve? Can I install my partition on the SSD and take advantage of it's speed while using the standard one for storage?

My SSD is small, 120 G so all I have on it is the OS and applications. In essence it is like having a small fast SSD internal with a large magnetic scratch drive for storage.

With all the standard Apple apps that come with OSX, garageBand, iMovie, iPhoto etc as well as LogicX and (hides his face} Warcraft, I have 35 GBs left. I have not moved all the LOgicX additional content, loops and Jam Packs to the storage drive yet but when I do it will free up another 4 GB. Basicaly you have to keep an eye on the SSD to ensure it does not fill up, if it is filling with application related files then they should be moved to the storage drive and have the application reroute, or in the case of Logic reindex this content and have save files saved to the storage drive.

I am unsure if there is any benifit to partitioning the SSD and might even be a bad thing to do. Why do you wish to do this?

I named the drives "my name SSD" and Storage just to keep it clear. This is only a temp fix. When there is an Apple update that fixes the FD prblem I will reunite the drives and have the software manage the two drives, as it was expected to do and as what we paid for.

Do you lose everything on the SSD when you split the FD? I really can't face another re-installation....

One more observation - with the caveat that I'm using GarageBand and and Line 6 Pod Studio KB37 rather than Logic.

I discovered that I can adjust the level of crackle and pop noise by adjusting the buffer size in the Line 6 Audio-MIDI Devices control panel in the system preferences.

Specifically - if I set the buffer at "Extra Small" I get unacceptable latency with only the intermittent click.

If I set the buffer at "Extra Large" I get a constant torrent of snap, crackle, pop with no noticible latency.

Interestingly, the latency effect is completely opposite the description below the buffer slider in the ToneDirect & USB Audio Streaming box, which says:

"Small buffers provide lower latency, but increased CPU usage."

I'm guessing the large buffer is addressing the FD more frequently and increasing the crackling. I don't quite understand why the latency is disappearing simultaneously.

I spoke to Line 6 and they are aware of the problem and working on it. They suggested that some people may get an improvement in fuction by rolling back to the previous, non-Mavericks driver. I'll post an update if that seems to work.

Has it been concluded that removing the fusion drive partition will solve not only the problems with the internal interface, but also external USB interfaces?

The more I think about it the more I lean towards removing my fusion drive partition. Except for the simplicity of having only one volume, in reality there are more benefits not using a fusion drive partition.

So is it a fact that if I split my fusion drive into ssd and mechanical, then my apogee interface will start working?

Kenny

Some interesting articles on the Fusion Drive technology.

https://www.google.com/#q=removing+Apple%27s+Fusion+Drive+Software

Completely software based.

It's not fully related perhaps, but just wanted to mention that I just installed the developer seed of 10.9.1 (I am a registered iOS and Mac developer) and it made no difference at all.

I didn't really expect it to, just saying.. 🙂

Thanks kenny.... and to confirm I found the same thing with the latest seed as well

(Yes, I am one of 'those' too 🙂)

Okay.. so after two plus days of testing, this is what I have found..

I have two identical 2013 iMacs with the exact same spec and OS X Mavericks /LPX versions except one has a Standard Mech HD installed (Ill label this one iMac HD) and the other has a 3TB Fusion Drive installed (Ill label this one iMac FD)

I also used identical LPX projects to test between both iMacs and LPX... and identical songs to test iTunes

I tested using a Motu Ultralite Mk2 FW400 Audio Interface and a Apogee Duet 2 USB both with the latest drivers available.

I worked with LPX on both iMacs for equal periods of time. 8+ hours on each and the rest of the time was spent with onboard Audio testng.. Maybe 2 hours on each.

Okay.. so... my findings...

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iMac HD with Internal Audio Only - No Audio issues at all.

iMac HD with Motu - No Audio Issues at all..

iMac HD with Apogee - Crackles/pops and audio dropout with Apogee.

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iMac FD with Internal Audio only - Crackles and Pops after different periods of time depending on loads placed on CoreAudio via LPX (Number of Audio tracks for example. The more audio tracks used, more likely the crackles and pops) Also same issues with iTunes and other Audio apps... but it was less than I expected based on reports I had read from those using Mountain Lion instead of Mavericks.

iMac FD with Motu - Brief moments of crackles and pops but these were rare. No complete crashes at all.

iMac FD with Apogee - Major problems with drop out and crashes of CoreAudio on a frequent basis.. via LPX and iTunes etc...

Booting the iMac FD from an external HD eliminated the issue with both the internal Audio and Motu.. but the Apogee issues continued... though maybe to a lesser frequency but it was hard to really tell to be honest.

I did not try the alternative "split" Fusion drive workaround because it isn't my Mac!

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Summary... (Inc personal opinions so others may differ!)

The iMac HD was far more stable in terms of Audio issues. They only surfaced when using the Apogee Duet 2

The iMac FD certainly has some bus/software related issues I suspect when streaming Audio via the FD drive or the FD is under load elsewhere. The Apogee issues remained much the same so i assume those are also related to driver incompatibilities still with Mavericks / USB3 ports. Booting from an external mech HD did fix all the Motu and internal Audio issues for me as expected. Again, the Apogee continued to have issues again, supporting my theory/opinon it's also down to driver/USB3 incompatibility problems with that particular Audio Interface.

I will also reitterate that my 2012 Mac Mini, that has a Fusion Drive fitted, does not have any audio issues with both internal and Motu. I did not test the Apogee with the 2012 Mac Mini however as I had to return it along with the iMac this morning.

Thoughts anyone?

Note: I am not claiming these results are based on very scientific methods of testing.. but more along the lines of just 'real world' use... and so other factors may be involved with different setups/uses.

Additional Note: I had hoped to test my Motu Ultralite Mk3 Hybrid which has both FW and USB connections with both imacs.. but unfortunately it was in use in the Main studio throughout the period of time I had the iMac FD to play/test with... so that wasn't possible.

thanks a lot, that is some great testing you've done there!

i am right now in the process of copying data as preparation for splitting my fusion drive. i haven't yet made up my mind to actually go through with it, and especially because your testing kind of shows that i'll still have problems with my apogee interface most likely.

however, for those thinking about splitting the fusion drive, i guess it depends on why you bought it from the beginning. for me personally it was for overall performance reasons - launching apps etc. but also for storage to not have to use my external drives like i did before.

so theoretically, i lose nothing by splitting it, as a matter of fact i gain the upside of being able to reinstall my system without having to copy terabytes of data each time. and also if one drive fails, a fusion drive setup will take the other drive with it.

so anyway, the fusion drive is purely for comfort i'll say..

i guess i'm saying it to process my own thoughts here.. 🙂

Kenny,

Bear in mind however, the Mech portion of the FD drive is only a 5400rpm HD.. and so it's performance if you use the Mech HD for audio samples/streaming etc.. will not be that great..... compared to an external 7200rpm FW or TBolt contected fast, non-green, HD

Test and see however... and fingers crossed!