Avid Pro Audio Community

Avid Pro Audio Community

How to Join & Post  •  Community Terms of Use  •  Help Us Help You

Knowledge Base Search  •  Community Search  •  Learn & Support


Avid Home Page

Go Back   Avid Pro Audio Community > Legacy Products > Pro Tools TDM Systems (Mac)

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 01-23-2007, 09:45 PM
Brian E Coombes Brian E Coombes is offline
Member
 
Join Date: Jan 2007
Location: New Hampshire
Posts: 3
Default Digital Noise Problem

Hello All-

I’m hoping someone here can help me with a strange noise problem I’m having with my Pro Tools HD system. I’ve been a PT user for years and have never encountered anything like this. I thought the problem was an isolated one and my workaround worked at first, but the problem seems to be spreading.

Here’s the basic system set-up that I have been using trouble-free since June 2006:

ProTools 7.1 (I was on 7.0, but Digi recommended going to 7.1)
Mac G5 PPC Dual 2.5 GHz
OSX 10.4.6
1.5 GB DDR SDRAM
OWC Mercury Elite Firewire drives (800 MB/sec) with Oxford chip set
(2) 192 I/O with expansion cards for 24 in/24 out
Clock Source: Internal
Only DigiRack and Waves Platinum (5.4.5) plugs
Delay compensation off when tracking
No plug-ins apart from Click inserted while tracking
Balanced power system for entire facility

Here’s the story:

1. Working in a session with live drums chopped and looped into a one measure pattern, copied for an entire 4 minute song, and consolidated into single files for each track. There are eight tracks of drums for the loop, including stereo tracks for Room mics and Over Heads.

2. Added a new stereo audio track to overdub a piano.

3. Headphone cue mix of drums is routed through a PT Send to Analog 7-8 of 192 #1 to Furman HDS6.

4. Control Room mix routed to Analog 1-2 of 192 #1 to Trident console, then monitors.

5. Record enable piano track.

6. When rolling (recording or playback), a digital noise (crackle, similar to extreme cell phone interference or clock issue noise) is heard in the headphone cue mix, specifically on the send for the Kick Drum (out) track.

7. Here’s the interesting part: Reassign the Kick Drum (out) Send signal to any other pair of outputs, then reassign back to Analog 7-8. Noise disappears from Kick Drum (out) and appears in Send for Room Mics.

8. Reassign send of Room Mics to any other pair of outputs, then assign back to Analog 7-8. Noise disappears from Room Mics but reappears in Send for Kick Drum (out).

9. Save and close session.

10. Reopen session.

11. Noise still present.

Something similar happened last week during a week of tracking sessions.

1. Working with 10-25 tracks of drums, percussion, bass, and guitar. Monitoring through Analog 1-2 on 192 #1.

2. Created a new track to record a vocal.

3. Record-enabled the track. The same noise mentioned above appeared.

4. Switched to all available inputs, noise still present. Disconnected all input connections to 192, noise still present.

5. Switch outputs to any other analog pair (noise disappears), then back to Analog 1-2, noise disappears.

6. Save session and close.

7. Reopen session. Repeat steps above. Noise present.

Here’s what I’ve tried:

Upgraded PT from 7.0 to 7.1 as recommended by Digi
Upgraded to OSX 10.4.6 as recommended by Digi
Disconnected all inputs to 192s
Switched outputs for monitoring to all available outputs on both 192s (3 different DA cards)
Reset all ribbon cables in 192s
Ran tests with single 192 to eliminate loop issues between the 2 units
Ran system on balanced and service power
Launched sessions in question from different drives, including system drive

Again, the noise goes away when I switch to another set of outputs then back to the originals. This has me thinking it's a software issue, not an hardware issue.

Any ideas? I'd appreciate any thoughts.

Thanks.

Brian
Reply With Quote
  #2  
Old 01-24-2007, 03:46 PM
Seeee Seeee is offline
Member
 
Join Date: May 2003
Location: Colorado
Posts: 1,050
Default Re: Digital Noise Problem

You certainly did your homework before signing up to ask this question. Hopefully someone will know something beyond my meesly input (no pun intended).

I was recording last night... OK, first off, i always record through a spdif converter into my 888/24 and I clock to it. But last night.. I didnt feel like changing my clock on the external because I was doing some 48k video stuff and wasnt going to be doing much so i just switched the clock to Internal. I started recording without thinking.. I am hearing pops and thinking.. mic cable, etc.. I asked myself.. "did i change to internal?" i checked and yup, it's 48k internal.. wtf... oHHHHHHH I am using the a/d and my a/d isnt clocked off anything nor driving anything.

Welcome to the DUC.
Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Structure Full - Digital click noise problem anthoven Virtual Instruments 0 04-17-2011 03:16 PM
96k 192k Digital Noise Problem? edison Pro Tools TDM Systems (Win) 4 11-19-2008 11:54 AM
digital noise Paul Alvarez 003, Mbox 2, Digi 002, original Mbox, Digi 001 (Mac) 4 05-02-2006 07:25 AM
Severe digital noise problem - please help DiscoD Pro Tools TDM Systems (Mac) 3 08-01-2005 08:15 PM
ADA8000 to Digi001 - digital noise problem uprightjazz 003, Mbox 2, Digi 002, original Mbox, Digi 001 (Win) 2 01-30-2005 06:38 PM


All times are GMT -7. The time now is 12:07 PM.


Powered by: vBulletin, Copyright ©2000 - 2008, Jelsoft Enterprises Limited. Forum Hosted By: URLJet.com