Lots Of Crackles When Recording In Powerbook Options

[camarao]

Hi

I have a Powerbook 15" 1.67hz 512 mb ram and a 80gb 5400rpm hard drive and a Terratec Phase 24 firewire soundcard.
I have installed all my software ( Logic Pro 7.01 and Kontakt 2.01 ) and started to do some recordings.
I was using a loop in track 1 , a EVP 88 with a tape delay and nothing else. I recorded thru the digital ins a 24 bit stereo file coming from a 01V Yamaha digital mixer.
When I started to listen to the audio files ( 15 to 20 minutes )they were good in some places and terribly bad in others with lots of crackles.
Does the OSX run some kind of background application that was interfering with the recording process ? Are there any tips to fine tune OSX in a Powerbook for audio production ?
Are my Powerbook specs enough for this job or do I have to buy an external disk just to record a simple 24 bit stereo file ?

Thank you

Alex

[banevt]

Its always a good idea to record your audio tracks on an external drive because the internal drive is 5400 RPM and a good firewire drive at 7200 RPM will definitely help. Another thing you can do is turn off the dock hiding and magnification and make your destop as simple as you can stand. I have tried this and it makes a difference. The way I heard it is that with OSX the all the little things like dock hiding and magnification take priority over your applications and can affect performance. In OS 9 you used to be able to set your memory allocation. Also you should check your playback buffer size. Is the audio crackling in the exact same places every time? If the crackling isn't in the same place every time it could mean that the audio you recorded is fine and your computer is just having trouble playing it all back which could be fixed later.

[gdoubleyou]

Max out your RAM, with 512MB you are forcing the OS to use your hard drive for virtual memory, not a good idea when trying to do hard disk recording.

You also need a 7200rpm firewire hard drive dedicated for audio files.

I have a 1GHZ powerbook with firewire drive and MOTU 828, no problems with sessions of 32-48 stereo tracks.

[cludinsk]

i use a powerbook with worse specs to record and dont have any problems. try playing with/removing each component, recording in analog, recording without mixer, etc, just to see which piece might be a problem.

[camarao]

Thank you !

I used a Pentium III 800mhz with 512 ram with Logic 5 and I never had this problem ( it's true that I recorded 16 bit files to a 7200 rpm drive ). Maybe the hard drive speed and the fact that you have a dedicated drive to audio ( as I has with the Pentium ) makes the difference.
I will try your tips and if you have more, please send them.

Thank you again !

Alex

[PristineRec]

Your computer is doing just fine. The problem you'e having is with digital sync. You mention you're going from digital outs from your mixer into your card into Logic. Something in that chain isn't syncing up right. Check to make sure everything is set at the same bit rate and sampling rates, and make sure your card and Logic are chasing the clock from your mixer.
I'm not familiar with any of the pieces you're using, so I can't help you with specifics on your equipment, but I have had digital clock issues before, and it shows up just like what you are experiencing.
Perhaps somebody else here knows how to get those pieces in digital harmony?

[kmslavik]

Digital Sync Problems

The problem will NOT be solved by setting everything to the same clock or sampling frequency (e.g. 44100 or 48000 Hz). Even when setting everything to same NOMINAL clock frequency there will be still some slight deviations within each single piece of equipment. This is due to the design and operating temperature of your equipment. These deviations are in the range of about 0.5 to 2 Hz which means that you can still have a few clicks every minute.

The best solution is to sync every piece of digital equipment from a common word clock generator. This is done in all professional audio and video facilities. In simple setups like yours you can sync the Audio Card to the incoming digital audio signal. You should be able to find that in the "extras" oder "setup" menue of your equipment and/or software.

Best regards, Karl

[PristineRec]

That is correct. That is why I included "make sure your card and Logic are chasing the clock from your mixer" in my previous post. One of the digital pieces must generate the clock that every other piece syncs to. And they will not sync if they are trying to operate at different sample rates.
I run a dbx preamp through S/PDIF into my Digi002r. In Pro Tools setup, there is a clock setting where I can tell Pro Tools to chase the clock of the signal coming in from the dbx preamp. If I change it so that Pro Tools syncs to it's own digital clock, I get crackles.
Again, I don't know where these settings are in Logic.

[camarao]

Well...I've just bought a Lacie Firewire drive and everything runs fine now.

Thank you, anyway.