Track Lag (revisited)

momo wrote on 5/16/2002, 11:15 AM
Hi – been reading back in the posts (and anywhere else I can find) about playback lag in Vegas, ie: as more tracks are added an eventual track-lag develops where playback lags behind previous tracks. Most things I’ve read so far point the finger at system limitations, pushing things too far, etc.

That makes sense, but I’m running Vegas 2.0 on a 1.8 GHz P4 with 256 MB of RAM, with over 40 GB free on the HD, using a Sound Blaster Live Platinum 5.1 sound card (latest drivers installed). In my opinion at least, this should be more than enough machine for 20+ tracks, but I generally can’t get beyond six before the lag inevitably develops. I know of others how are doing the same on PIII machines with less RAM and older sound cards that can still push more tracks than I can.

I'm running clean with no additional apps going in background.

Any thoughts, pointers, abuse? Known issues with the SB live plat?

Thanks all

Vegas 2.0
P4 1.8 GHz
256 MB
Sound Blaster Live Platinum 5.1
Windows 2000

Comments

Former user wrote on 5/16/2002, 11:29 AM
momo,

No problem here with track lag. I have run 24-40 tracks in Vegas 2.0 and 3.0 all the time with no problems. My setup is much less powerful (CPU wise) but much more powerful sound card wise (M-Audio Omni Studio/Delta 66) than your layout.

I have to ask why you would compromise such a machine by even considering a Soundblaster? This card is fine for listening to music now and then but for real recording (and real results), invest in a real card. In my travels, there has never been anyone that I have met that had any success marrying pro quality apps like Vegas to a Soundblaster...that card was not designed for the kind of I/O that digital recording requires.

I would suspect a complete turnaround in your track lag with a decent card.

Cheers,

Cuzin B

momo wrote on 5/16/2002, 11:44 AM
Tks for quick reply Cuzin,

Why did I compromise? Ignorance, I guess. Thought I was getting a good card. Additionally, I know others who use same card with no problems – I even know one fellow who uses a multiple soundcard setup, one is an SB AWE32 PCI, and the other is an old ISA sound blaster (!!), and it still works fine.

This being said, your point’s well taken. I guess I’m in the market for a new sound card, as I really need to get around this problem.

-momo

Former user wrote on 5/16/2002, 12:41 PM
momo,

Thanks for the honest response. I haven't been in the digital recording realm that long, but one lesson I (and others) have learned in this field is that compromise (especially with sound cards) is something that you want to try to avoid.

I always do a ton (And I mean a tON) of research before opening the old wallet for any gear. My sound card (Delta 66) is not that exotic and luckily not that expensive. It has been the brunt of many complaints in this and other forums BUT if you get past the configuration issues (which are almost all due to user oversight, drivers or some sort of OS massaging), this card has been wonderful for my operation. It always works and I use it everyday to handle a heavy load of recording, editing, mixing etc.

My point is - I could have spent a whole lot less on something else but my research indicated this was the way to go and I was proven right. My company provides services at a high level that my clients demand. As such, I need to choose my gear carefully and I can never tell them that I have any issues with software or hardware cause they just don't care about that, ya know?

Cheers,

Cuzin B

Sari wrote on 5/16/2002, 6:02 PM
Momo;

Check if DMA is checked on your hard disks.
Also Do you use one or two disks.
Do you have a lot of other programs running in the background (anti virus, task scheduler, etc..
momo wrote on 5/17/2002, 2:13 PM
Sari,

I have only one HD, and DMA is enabled. I run as clean as I can for background apps - I have no antivirus software (since, IMO, such things cause more problems than they prevent), no task scheduler, no anything in the application tray other than volume control.
Former user wrote on 5/17/2002, 2:41 PM
Momo/Sari,

No amount of DMA checking or background checks are going to fix this issue. The Soundblaster simply cannot handle this kind of action (despite what others will tell you).

Also running Vegas and your OS on the same drive is a big recipe for trouble. Twin drives are standard for an audio workstation. There is no way Windows and Vegas can compete for the system pipe and not conflict. Your drive controller will have quite the time trying to handle this clean.

Cuzin B
pwppch wrote on 5/18/2002, 5:03 PM
I want to clarify this, as I have seen some other reports behind this trag lagging.

1. Are you recording your tracks, using existing media? i.e. how are you getting media into Vegas?
2. Is the lag immediat or over time?
3. How is your routing/mixer set up inside Vegas?

Unless you are using multiple different outputs on your system, then Vegas can't lag audio that was recorded in sync. The sound card has NOTHING to do with this.

Tracks can loose sync because:
1. The audio was recorded at two different sample rates. That is, even if you recorded them at 44.1 kHz, unless the clocks were identical, then the tracks can loose sync from each other. Note that the SBLive cards (and Audigys) don'at actually support 44.1 kHz, but rather 48 kHz. They rely on Windows to resample to 44.1. Resampling can introduce sync loss.

2. You system is overtaxed and audio reading is stalled during reading. This would cause a lag, but also a subtle click or pop during playback. All tracks would still be sync'd together and lag together since all are being "driven" by the same audio hardware outputs.

3. Recording at one sample rate why playing back at another. This can cause sync issues with the SB cards because of the 48 kHz fixed sample rate.


With the SB Live, I would recommend you work only at 48 kHz. This will prevent Windows from having to resample in most cases. Be aware though that Windows can do a lot of funky things when with WDM drivers. You would be advised to disable all system sounds. Unfortunately you can't disable Windows use of the SBLive for any other sounds.

Peter





Snicks wrote on 5/21/2002, 8:52 AM
I kind of have the same problem. I press "SPACE" and my computer stops responding for20 seconds, then it starts playing. I use vegas video 3.0 for audio editing in my audio studio. I can't work if this happens... And sometimes, my cursor is getting nuts. The music stops, and the cursor is going right, left, (up and down:p) then the music continues and the cursor so.

Excuse me for my english... i hate my english teacher

10x
momo wrote on 5/21/2002, 9:59 AM
Peter (Sonic),

1. Are you recording your tracks, using existing media? i.e. how are you getting media into Vegas?

A: Crude as it may sound, I'm using the L/R outs from a 6-channel stereo mixer to the stereo miniphono line-in on the back of the sound card. It works, and allows me to have most of the junk in my studio hooked up and ready to go, although I record only one track at a time since I only have one input.

2. Is the lag immediate or over time?

A: Lag develops over time, and only after I’ve already recorded about eight or nine tracks. Monitoring previous tracks and laying down a new one is fine – no lags – however, on playback the new track will begin exhibiting latency usually about ½ way through, and gets worse after that. Obviously, samples are being lost. Sometimes there are pops, sometimes not. When monitoring previously recorded tracks, such noise is not readily apparent, however, the latency (lag) certainly is.

3. How is your routing/mixer set up inside Vegas?

A: Routing is through sound card (primary sound driver, only one available), and I record almost all tracks mono. I do this by choosing Left or Right input after record-enabling the track and making sure the associated input channel on my external mixer is panned appropriately.

Additional info: My default sample rate settings are 16 bit mono, 44,000 KHz – all tracks recorded using these settings. I’m not at home at the moment so I can’t check current settings, but I’m not sure if a 48 KHz setting is available.

Playback does not seem to be the issue - I've been given 16+ stereo track (veg session file plus associated wavs) sessions on CD by a buddy, and I can load this into Vegas and playback with no problems at all, including effects.

Additional ouputs: no outputs used other than stereo bus, line-out of the sound card.

Overtaxed – maybe... I’m not using a separate HD for recording and I probably should be. I’m looking into another HD purely for Vegas, preferably SCSI if I can afford it. Otherwise I run as lean and clean as I can when recording.

Thanks for your help – it is very much appreciated.