help with skips plz.

Skipping parts on music

What’s the cause of skips in the music during playback? And the dotted, up-and down-line (cursor, I guess) gets ahead of the wave during recording?

It only seems to happen more on longer recordings - typically greater than 3-4 minutes.

I’m guessing it’s buffer overruns. Did I guess right?

If that’s true, then I’m surprised, though because my buffering is set to 1024 samples. I have little experience though so that may be pretty low.

FIRST - what type of computer are you using, Laptop or PC ? - what make and speed is your processor ? - what soundcard are you using ? - what speed (RPM) is your hard drive ? - how many drives do you have ? - is DMA applied to hard drive/s ? - what version and build number of N are you using ? - what operating system are you using ?-

SECOND - how many tracks are you playing back ? -

REASON - laptops are usually slower in operating than PCs -

processor speed - the faster it is the more it can do without interupting audio playback

every soundcard has its own problems

minimum hard disk RPM for a DAW is thought to be 7000+ rpm ATA - 10000+ rpm SATA -

presuming you are using V5, then every build has some variation of the one before it, you may have a problen that using a different build number will rectify -

win 98se/ME/2000/XP home are OK, XP Media centre is not -

every track you playback add an extra load on the processor, every track is processed during playback even if there is no audio on the section of track - i.e 20 tracks on screen = 20 tracks sent to soundcard - if 10 of those tracks have gaps in the audio, the gaps are still processed and silence is sent to the soundcard -

two hard drives are better than one - (to long to explain here)

TECH NOTE - one of the most important / most misunderstood/ most unknown specs in a laptop/PC, is the FSB (front serial buss) the FSB is one of the ways that the processor communicates with other components on the motherboard - if you take two IDENTICAL computers, but one has an FSB of 800meg and one of 400meg, the computer with the 800meg FSB will be twice as fast -

So you see, the more info you give in your post - the quicker and more reliable the answers will be -

Dr J

the only way to learn is to find out - the only way to find out is to learn -

Thanks very much for the reply. I realize my post was short on information but I had a buzz and not the patience. I was hoping someone could give me a quick-n-dirty answer, but I should have know better.

So here’s my second try:

- PC -
Desktop PC - Dell Optiplex GX260
Intel 2.?GHz processor
1GB RAM

- Software -
OS - Windows XP Professional SP2
nTrack - v4.2.1 build 2099 (24-bit)

- Soundcard -
Delta 1010LT

- Drives -
0 - C: (OS and loading nTrack)
Barracuda ST340014A 7200RPM

1 - D: (nTrack temp and recording folders)
Western Digital Caviar - WD2000BB, 7200RPM

- Drive Interface -
Promise Ultra ATA/66
Both interfaces using UDMA mode 5
Each drive on it’s own bus
Each IDE cable is 80-wire

Recording -
5-8 tracks at a time.
24bit/96KHz rate

The nTrack CPU load indicator doesn’t typically go over 35%. I’m guessing the bottleneck is somewhere else.

Re: FSB - I have a few boards with the VIA chipset and have had horrible problems with pops when trying to use onboard preipherals. I often have to plug in cards to make my pops go away.

Thanks again and I’m anxiously refreshing for your reply!

Are you using wdm or asio drivers for the 1010lt?

I’m using the ASIO drivers

Are you using the control panel for the ASIO driver to set latency? Setting the buffer preferences in N-track has no effect on ASIO. Try setting latency near the max in driver control panel, and check to see if that has a beneficial effect.

T

thx fr th rply!

Yes - I’m setting the ASIO buffering settings outside of nTrack - when I was erroneously setting them from within, nTrack would trap and generally misbehave. I learned that one the hard way.

I’ll try upping the buffering settings the next time my band rehearses. I’ll report back. Thank you.

In the meantime, if anyone can suggest other things too investigate, please do!

everything looks good except for the word DELL regardless of the stated processor speed the ones i seen are very slow, OK for office work but!!! -

the other thing that jumps out is 96K - at this speed everything has to work TWICE as fast, i know its tempting to use the latest craze for high recording speed, this is ok if you have a dual Xeon or core duo based unit - in reality you gain very little in quality from 96k as it all gets lost when you convert down to 41000k at 16 bits when you burn your work onto a CD - so drop down to 48000k this still gives you the quality you want and audio will not be so mashed up when converted to CD quality -

on your DELTA 10/10lt control panel (here i am working by menory as my Delta 4/10 is in my studio and i use USB at home) on the page that you set your asio sample rate by you will see on the left side a tick box that stops any other application from messing it up, tick that box, above that are two tiny round dots for setting the buffer reset, click on BOTH to set them to ON -

when your DElTA left the factory it was set to MONO output, on the monitor page drag the pan controls full left and full right on all meters, and low and behold STEREO -

Windows and ASIO sample rate - you may be aware that windows cuts into any program that is running to do its own thing then hands control back to the program - the higher you set the ASIO sample rate the less chance there is of windows interupting your recording and playback, however the highest sample rate on the Delta is not high enough to cover all events, and the higher you go the slower N responds and it adds a huge amount of latency to audio and will make the PC useless for realtime monitoring - In a studio for recording they arrange for the musicians to hear themselves in realtime, not on audio that goes into and out again from the PC, i use a mixer pre N track from which i can take the realtime input to a headphone distribution amplifier for the musicians to hear thenselves as they play/sing, the output also goes into N at highest sample rate and no one is the wiser as latency does not show up on playback -

my little studio is recently new and i am still adding to it piece by piece as and when i can afford to i hope to soon renew my assiciation with ADAT as a means if inputting audio into the PC, as most of my equipment is ADAT enabled it will allow me to move up from two inputs at a time on the Delta 4/10 to 24 (16 tracks at a time from main mixer 8 tracks at a time from my mobile unit) - for working at home or in a project studio the 10/10 is ideal but you will run into latency problems no matter what soundcard you use -

if you are recording drums, latency is not a problem as the drummer does not need to hear themselves play - when recording guitars and synths, get the musicians to use the headphone socket on their amps/ keyboards (if fitted) so they can monitor themselves from there - then you can have the ASIO sample rate set to max all the time - open back headphones are good for this as they can set their own listening level to coinside with the sound passing through the phones -

hope this helps

Dr J

OK had a look at the specs for your Dell Optiplex GX260, its a corporate PC (i,e, office pC with multimedia capability) not as bad as i thought -

in your post you mentioned CPU use, you may be well aware of how this works, but i will run it by again for those who read this post who are not so clued up -

down in the bottom left of the N track screen you will find the CPU use meter, this tells you how much processing load is being applied to the processor, yes ? - NO it does not, it shows the processing load that N is adding to. on top of the system load (you have to use a different system to monitor the combined load) so what goes on ? -

OK on a CPU use scale of 1 to 100, the operating system takes first place here and lets say for instance that the operating system is using 50% of the available CPU processing time, then 0 CPU use as shown in N meter starts from there, N has only 50% of the available time to use -

the more background programs that are running while you are using N will limit the amount of CPU use there is for N to work with, if this SYSTEM USE was to reach 90% then the full scale of N meter would only cover the 10% of available CPU time that is left - not 100% as you may think,

now this is not exactly accurate but if you look at it this way it makes sense, at a system loading of say 70%, N can do nothing for 70 clock cycles out of a hundred - by lowering the background use to 50% N would work twice as fast -

another way of looking at it is to think of this as a clock where N has between 10 and 12 oclock to work with, N can do nothing outside of those times so it sits there idle unable to process your audio - the more time you give N on that clock the faster it will work and the less problems you will have -

95% of audio problems are nothing to do with N or your soundcard, its the amount of background processing that is going on that stops N from working - most of those things that sit in the right hand SYSTRAY on your screen can be killed without affecting your OS and every one you take out will give N more CPU time to work with -

--------------------------

BUILT IN Bluetooth and WiFi communication applictions can be a curse as they take up a lot of system time and are hard to kill, i only use plug in USB units that can be pulled and the drivers stopped at will - also running a lot of USB units will have two effects, first they add to the systen use and secondly they draw power from the PCs power supply which may already be stretched - XPs ‘smart’ power management system can limit the use of USB units that use to much power by switching them off when you least want it to happen - YOU SWITCH THIS ‘OFF’ AT YOUR OWN RISK -

a wireless unit that connects an PC to a router for the internet using a secure protocal will kill that PC practically stone dead as far as audio work is concerned - only on DIAL UP can you successfully use a PC for both (but not at the same time), a broadband connection even if it is by cable or optics is also ALWAYS ON grabbing huge chunks of CPU time that should go to N -

also be aware of high capability GRAPHIC CARDS they HOG more CPU time that anything else - you do not need them for audio work, my highest graphic card is 64 meg (laughingly small by todays standards) but i have more free CPU time and can use a lower speed processor than you if you are using the latest 3D cards -

yours Dr J

slight ammendment to post above N does not its show its own CPU use on the screen, just the amount of CPU that N is adding to total CPU use during playback -

more on CPU USE, where i show ‘PC’1’ this is my studio PC running my Delta 4/10 using ASIO and ‘PC 2’ indicates my home PC running Realtek AC97 MME

PC1 - 2 gig P3
PC2 - 932 meg P3

tested using 8 track song - 8 tracks to 2 outputs under realtek -
8 tracks to 8 outputs using Delta -

PC 1 = indicated CPU use 3.1% - actual CPU use 57% (max)
PC 2 = indicated CPU use 6.2% - actual CPU use 22% (max)

although this is not a direct comparison test it indicates that the Delta is adding a significent load to my PC -

even though it may add an extra load to my PC i would never swop my Delta for any other audio soundcard -

i did a comparison by playing back the same 8 tracks between N V4 and N V5 build 2174 on PC 2 and V5 uses lmuch less CPU than V4 -

found a great FREE cpu use monitor today, available from

http://www.topshareware.com/CPUMon-download-35923.htm

if you want to see whats going on with your CPU this is the monitor to use, its a lot easier to use than windows task monitor -


Dr J