Distorted audio on 2 laptops

[Spindoctor]

I'm open for comments on this one:

I've installed MIXXX 1.10 on my desktop, then on my laptop, and aside from a few documented bugs with AutoDJ both of these computers have run flawlessly. The desktop I listen to at times while working (home office), and the laptop has been used at several gigs. Both computers are 64 bit, windows 7.

A friend of mine has installed MIXXX 1.10 on two laptops. Both fo these are older machines, 32 bit, both running windows XP. I have been unable to gather more information about these, such as CPU usage or whatewver -- but I know they both respond very slowly when I load songs, etc.

Both of these computers have experienced problems. With one, a song will suddenly halt and make a loud buzzing sound, which is cleared by clicking anywhere on the MIXXX screen. On the other, the music will suddenly slow down and get distorted, as if it is stopping to load memory -- at a very rapid pace.

My suspicion is that both these computers have a memory problem, maybe too small a cache or just unable to process things fast enough. But what's strange is that in both cases, MIXXX will play just fine for awhile, then start doing this. In the case of the latter, exiting and reloading MIXXX will solve the problem -- for awhile.

I can assume a new 64 bit computer with windows 7 will solve the problem -- but it would be nice to know if others have indeed experienced such problems -- could latency adjustments help? What do you think?

As for the new computer, my friend tells me he wants to buy a certain machine from some catalog -- that may be great, but I'd hate to see money spent on something that for some reason won't do the job well. At this point I'm only assuming the problems are due to inadequate systems. I've seen these two computers and would agree that a new one would be a huge improvement regardless, but can anyone think of something to look for or stay away from when purchasing a new laptop?

[Spindoctor]

Okay, since posting the last message I've taken a crash course in everything I can find related to speed and sound protocol.

Both of my own computers are using Windows Directsound, and are actually working fine. However on the desktop I've found that it will handle WASAPI, so I've switched. Best of course is going to be ASIO. BUT -- how is this going to be found out when buying a laptop? Specs barely mention anything related to sound. External USB sound cards don't mention anything either. Suppose I want to buy a laptop whose sound is managed via ASIO; how do I go about it? Has anyone had experience with ASIO4ALL?

Any information you can give me is appreciated.

[Pegasus]

First of all, you're correct, ASIO is the best API to use, with WASAPI being just behind it. ASIO4ALL works really well and allows standard WDM drivers (which all sound cards can use,) to operate in the ASIO low-latency domain. So the first thing to check is if the card maker offers specific ASIO drivers for your card. If not, use ASIO4ALL.

After doing that and adjusting latency down as much as possible without clicks or pops, if a system later acts up as your friends' do, start Windows' Performance Monitor under Administrative Tools in the Control Panel. It should begin displaying a graph of CPU usage, disk usage, and memory usage. You can also start Task Manager, click the Processes tab, the click the CPU column to sort by CPU use. That will tell you if something else is using the CPU and starving Mixxx. Also check to see if the system is low on memory (PF usage is high on the Performance tab) since when the system has to access swap space often, it slows everything down. The remedy for that is to make sure all unneeded stuff is closed (many things that auto-start on boot-up for example, like RealPlayer, QuickTime, LibreOffice QuickStarter, etc.) or to add more RAM to the system board.

[Spindoctor]

Thanks for the reply. My friend has given up on one of the computers, using the other one exclusively. What's interesting is that MIXXX plays well for the first hour or so, then starts acting up. If MIXXX is closed then reopened, it works fine again for awhile.

There are two other factors that make this scenario a mess. First, I only get to see/hear this when he is at a gig playing it, so I can't get in there and look at things, and secocnd, there are too many cooks in the broth. Others come into the trailer and say it's the software, the computer must be getting hot, it's a program bug, yada yada. One of these guys gave him this laptop and swears by it -- it's the fastest, cleanest, most powerful thing since sliced bread. Yah, right, 32 bit XP with a screen so tiny you can't half see it. Whatever shots in the dark these guys have to offer, I'm about 99% certain the problem is latency. I CAN tell you this computer has been cleaned off, so not much else is running except MIXXX.

Last night it acted up again; I grabbed MINE, which has performed perfectly from the beginning. While his was still on, I managed to increase the latency. He has a couple of gigs this weekend; I'm not there (too much work to do -- I run a business). But I'll check with him later to see how it acted. Ultimately a new laptop will be the ticket, further improved with an external sound card that runs ASIO.

[Spindoctor]

We ran "Little Red" (what we call this tiny red laptop) Friday for awhile and and Saturday night from beginning to end. Latency was 42.7ms, sampling 44,100. Did not act up, BUT -- I noticed a few very slight blips in the music; had to listen close but they were there. The next latency step is something like 80ms, not sure if I want to go that slow. But maybe I'll try out ASIO4ALL and see what that does for it.