Anyone having crackles/slowdowns, read this.

I was browsing around here and noticed some people having random crackles in their audio. Well here’s the cause and some solutions. Most of this stuff will work for you as it worked for me and for other people, but there’s no guarantee. If you do still run into trouble i’ll try to help you.

So why does it crackle? The cause is DPC latency spikes. I won’t talk about what DPC latency is in technical terms, you’re free to look it up at Microsoft and read it yourself. But basically a driver is taking too much time to process low-level calls and interrupts everything else, namely sound and video. The reason is that Windows is NOT a true real-time system, there are lots of timers and calls and interrupts that (try to) keep the system running fluidly. Unfortunately they do not succeed all the time, partly because of programmers that don’t follow driver writing guidelines, partly because of other things i’m too lazy to list.

So, it goes like this. Most of you DJs probably have laptops (i have two myself), so i’ll focus on them. Please note that this applies if you have done everything and still have crackling/skipping/slowing down audio, even with large buffer sizes and/or ASIO.

1. Clean install. Yes you’ll laugh maybe, but DO IT. It’s of paramount importance to get rid of all the junk your computer manufacturer installs. I haven’t seen ONE laptop come from the factory with a properly installed operating system. Right now, Windows 7 64-bit is my operating system of choice. Vista 64-bit would be the second choice, Vista isn’t all that bad in 64, but Win7 is still a lot better. It’s for Vista what XP was for 2000 if you like it this way. XP is still a good choice for slower machines and netbooks, but it’s being phased out so do upgrade.

2. Don’t just install everything from the computer manufacturer page and call it a day. Don’t install ANY of the manufacturer supplied software (i’m talking crap media players, volume OSDs and the like). Especially the volume OSD on HP laptops is one of the worst things i have ever seen. It crashes most fullscreen apps, and if it doesn’t, it slows everything down to a crawl while it’s displayed. It’s so slow that you end up swiping the volume bar again and again without response, then it suddenly jumps to maximum. And if you NEED a volume OSD in the middle of your screen… buy a TV okay.

Hunt for drivers on the card manufacturer pages not on the computer manufacturer (except audio if you use the onboard soundcard, as that’s usually customized for that particular model). Especially WIRELESS drivers, they can be a major headache when it comes to sound. Turn off PowerMizer if you got a nVidia GPU in your laptop. Be aware that this will make it run hotter but if you don’t game on it use the nVidia Performance utility to make the clocks run at low frequency all the time and keep it cool.

Here’s a few places you can get drivers from.
http://ati.amd.com (ATi Graphics)
http://www.hardwareheaven.com/modtool.php (modding tool, makes desktop drivers you get from ati.amd.com compatible with your laptop) No more waiting for updates from your computer maker! Unfortunately it does not support the latest chips but it works for up to HD4800 series.
http://www.nvidia.com (nVidia Graphics)
http://www.laptopvideo2go.com (nVidia Graphics for laptop users) I recommend Dox’s modified Forceware 185.85, is 15-25% faster than any other version including the latest, and there is no decrease in quality.

http://www.intel.com (Intel Corporation, for chipset drivers, integrated graphics drivers, and WIRELESS drivers (always be up to date with wireless drivers or funny things can happen)
http://www.broadcom.com/support/ (Broadcom, Wireless drivers)

http://www.synaptics.com/ (Touchpad drivers)

Okay, did all this? Still getting crackles?
3. Investigating. Download the DPC Latency Checker: http://www.thesycon.de/deu/latency_check.shtml Run it and see if you get any red bars. If you do, turn off devices one by one. Start with the wireless card, then onboard sound, any USB peripherals, you get the idea. If everything is green but you STILL get crackles, get the Microsoft Windows Performance Toolkit and have fun… That is a topic of its own so if you need help with it let me know.

Edit: A new tool has come to my attention. It is called LatencyMon and can be downloaded from here. It will not only tell you your driver latency, it’ll also point out the offenders! How cool is that.

Blabber removed.