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Building a Home Theater PC (HTPC)

Larry Templeton 

(REVISED Jan 2010)

At the April 2009 SPAUG meeting, member Larry Templeton described how he built his own Home Theater PC. 

Bill Young really laid the groundwork for tonight's talk a couple of month's ago when he made a presentation to the group about how to build a standard desktop for the PC so I'm not going to go into the nuts and bolts of it, but I do want to talk how they work, how they fit into a home entertainment system and the parts that you might want to procure if you are going to build one.

What can an HTPC provide? 
  • Record /store/ replay off-air/cable TV shows, DVDs, CDs, ipod, MP3s, etc. 
  • From the internet, download /store /play YouTube, Hulu, Netflix, TV shows, movies  (amazing amount of content now available)
  • Edit video, burn DVDs, CDs, load iPod, etc.
  • Any other PC function such as surf the  internet, play games, etc.
  • Watch off-air, cable & satellite TV
  • Get rid of all your old CDs, DVDs, etc.

Ubuntu, Windows and Virtual Computers

At the July 2009 General Meeting Hank Skawinski promoted Ubuntu as a better operating system (OS) than Windows. Hank showed us his new netbook computer that dual-boots Windows XP and Ubuntu. He booted into Ubuntu and showed us many of its features. Hank noted that Ubuntu cannot run some critical Windows programs, such as TurboTax, Quicken, QuickBooks, and Photoshop. This keeps many users from considering Ubuntu.

Using a virtual computer, I am running Windows XP and Windows programs, including the above programs, in Ubuntu. As a timely follow up to Hank's talk, Hank and Jim Dinkey asked me to describe to the club members how I do this. 

Wildlife Photography at Your Local Zoo

Budget Safari title photo of a snow leopardMost of us love looking at photos of wild animals, but few of us can afford the expense of a safari to the places where they live in order to take the pictures ourselves. But there is another option available to us. Our local zoo. On June 19, 2009 Bogen Imaging presented a webinar with Julie Larsen Maher, the head photographer for the Wildlife Conservation Society which oversees the major zoos in New York City. This webinar, which might be titled "Safari on a Budget" was replayed at the July DISIG meeting. For those who were unable to see it, I have compiled a list of the many tips and tricks which Julie described along with a few of her superb photos. If you want to see the entire one hour webinar, you can visit the Bogen Café site.

How to Build Your Own Computer

 
In February 2009 SPAUG member Bill Young described how he designed and built a "general purpose" desktop computer, including:
  • Choosing whether to buy or build your new computer
  • The ease of building your own computer
  • Deciding on the objectives for your computer
  • Selection of hardware components to meet your objectives
  • Choosing your operating system

The advantages of building your own system include custom components wth better reliability and longer life, lower power consumption and cooler, quieter operation compared to purchased computers.

Removing Pops and Clicks with Audacity

Many people have collections of vinyl recordings which they would like to transfer to digital format. At the March 2, 2009 meeting of the Multimedia SIG Bob White presented suggestions for how to enhance the quality of these transfers by removing extraneous noise ("pops" and "clicks") from these recordings.

Before you begin, Read tutorials for LP transfer on the audacity wiki:
http://audacityteam.org/wiki/index.php?title=Transferring_tapes_and_records_to_computer_or_CD
There is some really good information here, especially about equalization curves on older records, which probably isn't available any other way, let alone so convenient!

The wiki also has suggestions for pop and click removal:
http://audacityteam.org/wiki/index.php?title=Click_Removal

If you're going to digitize some old records, start by cleaning up the record(s) as best you can. I use an audioquest anti-static record cleaner: Go to http://www.audioquest.com/ then go to the Accessories tab, select  "Vital Vinyl" and scroll down to “Record Brush” (A list of dealers carrying this brush can be found under the "Dealer Locator" tab)

  • After setting your record on the rotating turntable, apply the brush gently to the record with the long axis radial and the inner end covering the lead out groove. Bristles should be perpendicular to the record surface and just barely deflected by the  record's rotation. Let the record spin about 3 turns.
  • Next pivot the brush about 45 degrees to the radius by moving the inner end “forward”, i.e. towards the oncoming grooves (over about 1 turn). Then sweep the brush forward (perpendicular to it's long axis) and off the record, over about 5 turns. This should sweep any collected dust off the record.
  • Move the brush away from the record and turn its handle (bail) under the bristles to shake loose the accumulated dust. (A short version of these instructions appears on the back of the brush's package.)

I have not used any of the liquid “washers”, but they may be very effective. If you use one, DON'T use tap water with it. This will leave residue, such as precipitated calcium, which will add surface noise to the groove and which you will never be able to remove. Ensure your liquid washer removes ALL of the liquid (and dirt, of course!) and leaves NO residue! Consult with someone who has experience with such a washer.

Store your newly cleaned record in a poly lined paper sleeve, for example as found at:
http://www.turntablebasics.com/sleeves.html

If the original cardboard jacket has disappeared or disintegrated, the same website offers new clean ones. You want a jacket for mechanical protection and the original one usually is good enough. The original jacket is a significant part of the record's historical (and monetary!) value and should NEVER be discarded.

Having spent several more hours removing pops & clicks (these weren't my first transfers) I have a few observations about the process:

  1. Using the Zoom controls, set a time scale with tick marks every second and time labels every 5 seconds. I've found this works pretty well for locating pops and clicks. Fit the tracks vertically (View -> Fit Vertically) to give yourself plenty of room to work. You should get something like:Audacity window
  2. Your ear is by far the best instrument to find pops and clicks. (Note the spike just before 32 seconds in the nearby image.) As audacity plays, lead the playback time line slightly with the mouse cursor, and click on a noise to set a mark. Then quickly stop playback. With experience you will be able to visually spot and "camp out" on noise candidates, which can be clicked on if they correspond to actual noise.
  3. Your eye is the best instrument to zero-in on a suspect click or pop. Mouse clicks, magnify icon or Ctl+1 keep zoom centered on your marker. (See note below.) Re-target the time marker as needed, for example after about 6 clicks of “zoom”, to keep it on the central zero-crossing of the noise spike. If the spike isn't fairly narrow (200 - 500 microseconds) it's probably not a pop or click. Time scale tick marks are now 100 microseconds apart and you'll see something like:
  4. Choose the draw tool (looks like a pencil). Draw icon
  5. Re-draw the waveforms as needed to eliminate spikes. Set the draw tool on the dot left of the first one you wish to change, then drag the tool through the disturbance to correct the waveform. You can go back and modify individual dots if you wish. Usually the spike is much more prominent in one channel than the other, but consider redrawing the less affected channel as well. Do the best you can with shaping the waveform, and don't worry about it. You're dealing with a VERY small time slice, and just getting the spike cut down will be a MAJOR improvement! Result should look like the following:
    corrected Audacity waveform
  6. Choose the selection tool (to prevent accidents!).
  7. Zoom back out, should be 13 clicks (Ctl+3).Zoom Out icon
  8. Back up a few seconds and re-play the section. Pop or click will be gone.
  9. With experience you'll realize how short pops and clicks are compared to desired sounds. This will guide you in determining what to try removing.
  10. Think cosine-squared.
    Audacity cosine squared waveform
    Pops and clicks approximate this shape, which means there may be small deflections before and after the main peak which go in the opposite direction. Plan to remove these as well if you see them.
  11. 90% of pulses will need the first 10% of your time to remove. Always be aware of when your work is good enough! Do you want to take a LOT more time to chase the last 10%? MAYBE you do, but make it a conscious, informed decision!
  12. Inter-band gaps: At about 5:11 to 5:19 the example recording has a gap between bands. Typically there is surface noise here which you might want to suppress. In the example recording the original tape had a paper leader in the gap so is known to have been completely silent. Zoom to this region using Stan's method, which is superior for this purpose. Then select exactly the region you want to silence and use Edit -> Silence (Ctl+L) to remove the noise. This may seem redundant (see Recording strategy) but it makes band gaps easier to identify later.

Note on zoom:
Stan suggests making a selection over the click or pop by dragging the marker, then use Ctl+E to zoom to the selection. Typically this will need 2 “select and zooms” to get to an editable expansion. The resulting scale may not be what you'd like to work with. You may prefer this to the “13 click” method. I recommend trying both methods and use what works best for you.

Recording strategy:
Record an entire side at a time into a single Audacity project. Remove tone-arm drop & lift noise by selecting each region and deleting (Edit ->  Delete or Ctl+K). Keep each side as a single project during clean-up. After clean-up, use selection (Edit -> Selection Save) to separate bands into individual files for burning to CD. In the save step you can determine file type (.wav, .mp3, etc.). In the CD burner setup you can insert inter-band silences.

Open Source Software - Is There Really a Free Lunch?

From Linux, Open Office, Firefox and GIMP to a growing list of other applications Open Source has become a popular alternative to costly commercial software. Open source software is developed by a community of programmers with peer review and transparency of process. The promise of open source is better quality, higher reliability, more flexibility, lower cost, and an end to predatory vendor lock-in. (Presented by Maurice Green at the August 2008 General meeting. Additional material and links have been added.)

Use of Kodak Plug-in Filters for Photoshop

Plug-ins are small independent programs which perform functions within the photo editing program (e.g. Photoshop). Hundreds of plug-ins are available, some for free, Many plug-ins provide more levels of adjustment or more sophisticated ways of performing normal image correcting functions such as sharpening or applying smoothing blurs. In the examples shown the original unedited image is shown followed by the result using different techniques for achieving the desired correction. Each image represents a single technique; effects are not applied sequentially. This lecture/demonstration was presented at the October 2005 DISIG meeting.

KAP: Kite Aerial Photography

Bruce Owen, PhD
Sonoma State University

Pillistay site thumbnailWhile poring over aerial photos of a coastal valley in southern Peru, I noticed the fuzzy images of several large, complex, grid-planned sites in a virtually unknown region. Visiting the sites, it was easy to see that the architecture was complicated, but difficult to understand the layout from the ground. Some aspects of the plan and walls suggested that the sites might have been built by the Wari, a pre-Inka expansive state dating to around AD 500 to 1000, but a millennium or so of debris flows from the valley walls and a layer of volcanic ash from AD 1600 cover the surface, hiding the artifacts that would normally help to date the sites. Understanding the architecture will be key to guiding excavations in three of these sites this summer, and to accurately mapping them using a sophisticated GPS and laser rangefinder system.

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