Since the wider bandwidth recordings for Perseus have been available there have been users who have suffered the dreaded "Audio Stutter" during playback. This either sounds like the audio has stuck in a very quick loop or the audio pauses for awhile then resumes.
So; let's see how we can tackle this. First off we need to ensure that we are really looking for a problem. Check to see if you can record lower bandwidths without issues. Let's assume anything up to 800 KHz is fine. Yes/No if no then you're going to have to look at issues like is the PC up-to making recordings and playing them back - A 800Mhz PIII with an old IDE drive is probably never going to do the job you want it to! Perseus LIKES modern hardware, remember here the software eats CPU cycles and disk IO when playing back very large files, you'll need your PC in tip top shape to work well.
So a check list of the PC "newbie’s", Is your CPU single or dual core? Dual is better. Is the CPU speed above 1.6Ghz?. Does the PC have IDE or SATA drives? SATA are much better at reading large files, IDE is *ok* but really you need to ensure your recording to and reading from a SATA drive if you have one. Are you using a laptop? Remember a laptop from the "box" is designed to give the longest battery life not best performance.
You'll need to delve into the BIOS settings and make sure that any power saving options are "Off" or "Minimal" AND if there are options for the speed then set these to "Fast" or "Performance". Once you've got those pesky battery saving options off you'll want to tell Windows that you’re a power user and not worried about battery life!
OK. Lets start in Vista. Open power options by simply typing Power Options in the search bar from the start button. Or, go the long way and, click the Start button / Control Panel / Hardware & Sound / Power Options. Click the radio button next to "High Performance" then click "Change plan settings" then click "Change advanced power settings" to continue … Change "USB selective suspend settings" and "Turn off hard disk" to "Disable" and "Never". Once you have made these changes click "OK" to dismiss the dialog box and then close the power settings applet from the control panel.
For laptop and desktop PC users they are probably the most important things to change. You can always have a fiddle with other options if you want to - if you get into a mess you can always choose the "Restore plan default settings" and you'll be back where you started.
For Windows 7 users (I know RTM is not here yet but a-lot of people have RC1 or have access to the RTM from MSDN or TECHNET so you might be using it now as your main OS) the procedure is the same. For Windows XP users click Start, click Control Panel, click Performance and Maintenance, and then click Power Options. In the Power Options dialog box, you set options for a power scheme. Windows XP comes with several preconfigured profiles. From the drop down list choose "Home/Office Desk". That's the one that offers the least power saving and maximum performance, which is what we want for Perseus recording. Don't choose "Minimal Power Management" which is misleading as this leaves the chipset and CPU to decide for you what power scheme they want to use and it is not a minimal power profile!
There are many articles on the web about power management and Google is your friend for XP, Vista or Windows 7.
Right, we have the power management sorted, moving on lets see what else we can tinker with. Under Vista and Windows 7 there are some options to improve the hard drives performance, lets have a look at them.
1. Open the Control Panel.
2. Click on the Device Manager icon.
3. Click Continue button for UAC prompt.
4. Close the Control Panel.
5. Click on Disk drives to expand it.
6. Right click on your hard drive device listing and click Properties
7. Click on the Policies tab.
8. For a ATA (Parallel) or Serial ATA (SATA) Hard Drive -
A) Check the Enable write caching on the disk box.
B) Check the Enable Advanced performance box.
9. For an External Hard Drive -
A) Dot Optimize for performance.
10. Click OK to apply. Windows will require a reboot for this to take effect.
Note there is an increased risk with these options that should your PC or laptop lose power then all the data in memory due to be written to the hard disk will be lost. For a laptop user this may not be an issue. As you have a battery to fallback on but a home PC should be on a UPS (even a small one) if you're going to set these options this way.
You've been warned!
There are however some external options that can be explored. If you want better performance for recording and playback one way is to get an external drive. This can be USB2 or eSATA* it does not really matter the choice is based on what your laptop has for external connections OR what PCI card your desktop PC can take. All modern machines should have a USB2 port - that's want you want to use - in fact if you're using a Perseus YOU must have a USB2 port for it to work properly.
If you're buying an external drive then try and get one that needs its own PSU. They are faster than ones powered off the USB bus. You'll find they are normally a faster drive than the bus powered ones and that they normally have larger caches (which are important) and you get the advantage they are not sucking valuable USB power from your laptop or desktop PCs internal USB hub!
As for choosing an external drive look for these three features. The drive rotation speed needs to be 7200rpm (and not the older slower 5400rpm) make sure you get a cache size that is at least 16mb and most importantly a USB2 interface not 1.1. If you're getting one that is externally powered you should shop about as several do come with linear power supplies and not a switched mode supply and this will help keep shack RFI down.
As for what to get, I'm not going to promote any particular drive or drive maker but the Seagate ST305004FDD2E1-RK works well ;-)
* If you have an eSata interface then the rules are pretty much the same as for USB2 drives. A quick Google shows the 1TB Freecom 29416 would be a very good choice as a starting model to shop about for and good to compare specifications with. IO performance for eSATA should be better than USB2 but this should not be a reason to boycott USB2 in favour of eSATA. eSATA does cost more and you have fewer options in the market place to choose from.
Hopefully we are on our way now to getting reliable playback and recording with your Perseus!
In part 2 I will go over running Perseus in "high" mode, changing some registry settings, checking on what else your PC is running in the background that you may not need and setting up a new login profile with minimal options enabled that will offer a small working memory footprint and run only the most essential Windows services and programs at start up. Stay tuned!
73
Subscribe