clipping sound on new iMac when Logix X is running

A logic update isn't going to fix what is obviously an OS issue unfortunatley.

fair enough... just wishful hoping. hehe

shipsupt wrote:

The details of my problems have been somewhat different from most of what I've seen on this thread, but they do seem related. From those I've found and read, this thread appears to best capture the issues and potential solutions. So I thought I'd share what I've experienced and the current situation.

I purchased a new iMac 27" with fusion drive about a month ago. One of the major uses of the iMac for me is sending audio via USB to a DAC for conversion and playback. I immediately started to have issues with USB playback. Within minutes of playing music through several DACs I would encounter "pops" and "clicks". It did not seem to matter what software I was using for playback. Playback throught the internal speakers never seemed to be show any of the same symtoms, only playback through USB.

I tested all the same DACs and software using a MacBook Air and an older iMac and did not have any issues.

I started working with AppleCare and was put in contact with a higher level technician. We spend some time running diagnotics, updating software and drivers, doing resets, changing DACs etc... Most of the typical thing you would try, with no success.

Close to 14 days I sent the iMac back and got a replacement. I considered getting one with the fusion drive, but wanted to give the new hardward one more try.

Initially I had the same issues, in fact at times the distortion would grow worse until play back would completely stop. This time we did a data dump and sent it off to the engineers at Apple. Unfortuntately I had to leave town for 5 days. I left the iMac running in the mean time. Now, upon my return I have been listening for several hours straight with NO pops or clicks.

Ugh... I really hate intermittent problems and magic fixes. I don't think there has been a firmware update or OS update in that time, so I'm at a loss as to what has changed! (Crazy assumption not based on any solid engineering, the fusion drive has made some changes to what it's priortizing and buffering?)

The AppleCare guys have been awesome, and the first return was conducted with no questions. My case is still open at this point. They have indicated that there is "some issue" but at this point no root cause is clear and no fix identified.

I plan to run like this for a while and see if the performance continues. I know this is slightly different than the original posters problem, but from the symptoms you guys are describing it's the closest I've seen to mine. I'll post up a progress report and of course anything we learn during troubleshooting.

I'll be running close to the 14 day window soon, and I'd prefer to send this one back for a non-Fusion drive if I continue to have issues, but with this miracle cure I'm waiting to see...

Curious if anyone else has had spontaneous repair, or noticed the problems disappear only to have them come back later??

Here are a few hardware and software details of the gear I've been using:

Model Name: iMac

Model Identifier: iMac14,2

Processor Name: Intel Core i7

Processor Speed: 3.5 GHz

Memory: 32 GB

Boot ROM Version: IM142.0118.B00

SMC Version (system): 2.15f2

NVIDIA GeForce GTX 780M

3 TB Fusion Drive

Running OSX 10.9

Digital to Analog Converters Tested

HeadAmp Pico DAC

Cambridge Audio DacMagic

NAD M51

Software which playback noise/distortion was noticed:

iTunes

YouTube via Safari

YouTube via FireFox

Channel D PureMusic

Audirvana

J River Media Center 19

A bit of a final update of my story... After working with Apple support on some work arounds that seemed to work, but left me "working around" I decided to go another direction while Apple works on the fix. I've set up a dedicated music server using a Mac Mini and releived my new iMac from music duties.

In the mean time, my Apple care guy said that clearly there is an issue with the FD (no news to you guys) and a fix is forthcoming.... when is the question!?

Good luck in the mean time guys.

I updated both - Logic Pro to 10.0.5 and OSX to the latest developer seed 10.9.2. I have also rebuilt the fusion drive which I splitted before but that splitting did not solve my problems entirely plus the lower performance is really noticable. Anyways, it feels like the highpitchted distortions I experience appear less often and less long now but they are still present.

This is my setup:

- Late 2013 iMac FD 3TB, 32GB Ram

- Anker USB 3.0 9-Port Hub where all external USB devices are connected to

- Allen & Heath QU-16 Digital Mixer which also is my audio interface

Maybe it's wishful thinking but I tend to believe that some things in 10.9.2 address either USB or FusionDrive problems or things just improved because I tried so many work arounds in the last couple of days.

Either way - we are still not there yet.

-act

As far as I am aware, the current Dev release of 10.9.2 does not have anything in it, to address the FD issue specifically... and the USB issue isn't one for Apple to fix....

Thanks for the info - well I guess that the USB-Hub may then be the item in question that improved the situation a bit for me. Originally with FD and Audio Interface connected directly to the iMac, audio was really unusable.

-act

Yes.. Many people have reported using a powered hub improves matters by quite some degree for them....

But that doesn't help with the FD issue.. just with the USB2/3 issue 🙂

...and of course, you can have both issues if you have a 2013 iMac with an FD fitted and a USB2 device plugged into a USB3 port....

The Art of Sound,

Is there a way of discerning whether I'm dealing with the USB2/3 issue or the FD issue? In my case, I'm not using an interface. I'm using a Logitech headset, Blue Yeti mic, and Griffin iMic. They all work fine on my MBA, but not on my iMac. For that reason I suspect it's a FD issue, because both my iMac and MBA have USB3 ports.

Hey switters,

There is no easy answer to this....

But....

The best way to be reasonably sure.. is to eliminate the FD from the system.. by means of splitting it or using an ext HD to boot from.... and then test..

However... just to throw 'mud into the water'.. a client of mine has a MBP with USB3 ports and an iMac without FD but with USB3 ports... and his Logitech USB2 HD Cam works great on his iMac but keeps losing audio on his MBP.. This is using identical OS X versions (10.8.5) and Video/Audio Capture software on both... No idea if this is a USB2/3 issue or simply something else going on... as i am not the one troubleshooting this issue with him.. (Not my field!) but it's worth bearing in mind...

Am really disappointed with whole experience , I got the charger from Motu updated to latest version my device keeps blinking 44 and 48 mix without being able to get any sound out of it . I tried the usb and firewire and usb hub both with no chance it makes my mac freezes and feels buggy . I cant get any sound what a waste of purchase

Is the clock on the Motu unit set to Internal? It should be.

+1 Pancenter....

Also... If you have the digital I/O of the MOTU hooked up by s/pdif unplug the cable that goes to "Digital In"

btw Pancenter... I never saw your reply in the "How do i make my voice higher" thread before it got deleted! 🙂

Which one of us, said the 'wrong' thing i wonder?

*grin*