Schedule

Schedule

Wednesday, March 4

1425492000 Tech News Today
1425495600 Windows Weekly
1425502800 This Week in Google
1425513600 Tech News 2Night
1425515400 Android App Arena
1425520800 Ham Nation

Thursday, March 5

1425578400 Tech News Today
1425582000 Know How...
1425587400 Marketing Mavericks
1425592800 Home Theater Geeks
1425600000 Tech News 2Night
1425601800 The Giz Wiz

Friday, March 6

1425664800 Tech News Today
1425668400 This Week in Law
1425679200 Before You Buy
1425686400 Tech News 2Night
1425690000 Padre's Corner

Saturday, March 7

1425754800 The Tech Guy

Sunday, March 8

1425837600 The Tech Guy
1425852000 This Week in Tech

Monday, March 9

1425920400 Tech News Today
1425924000 Triangulation
1425929400 iPad Today
1425936600 Coding 101
1425942000 Tech News 2Night

Tuesday, March 10

1426006800 Tech News Today
1426010400 MacBreak Weekly
1426019400 Security Now
1426028400 Tech News 2Night
1426032000 All About Android

Wednesday, March 11

1426087800 FLOSS Weekly
1426093200 Tech News Today
1426096800 Windows Weekly
1426104000 This Week in Google
1426114800 Tech News 2Night
1426116600 Android App Arena
1426122000 Ham Nation

Thursday, March 12

1426179600 Tech News Today
1426183200 Know How...
1426188600 Marketing Mavericks
1426194000 Home Theater Geeks
1426201200 Tech News 2Night
1426203000 The Giz Wiz

Friday, March 13

1426266000 Tech News Today
1426269600 This Week in Law
1426280400 Before You Buy
1426287600 Tech News 2Night
1426291200 Padre's Corner

Most Recent Episodes

All About Android

Mobile World Congress, HTC One M9 and hands on with the Samsung Galaxy S6.

TWiT Live Specials

Acer Liquid M220, Alcatel OneTouch Idol 3, Gionee Elife S5.1, and more.

Security Now

SoHo router backdoors, web-based encryption service, evolution of DNS

Tech News 2Night

Shilling pitches back at trolls.

MacBreak Weekly

Apple Watch leaks.

Tech News Today

Updates from Mobile World Congress Day 2.

Coding 101

We finish our Arduino clock.

Tech News 2Night

Google Wireless is coming.

Triangulation

Becky Worley is the tech contributor for ABC.

TWiT Live Specials

Samsung Galaxy S6 Edge, HTC One M9, Acer Liquid Jade Z, and more.

Know How... 64

Audio Calibration and Wiretapping 101

October 10 2013

Today you'll know how to tap your network using Wireshark, how to fine tune your home theater audio, and more.

Wiretapping Your Home

Step 1: Get a Tapping device

Step 2: Get a device capable of receiving the tap data stream

  • Anything with a WIRED port that is capable of receiving the full speed of your chosen tap
  • USB adapters are fine, but remember that USB 2.0 devices top out at 480Mbps. If you’re using a Gig tap, you’ll drop traffic once the pipe is less than half full.

Step 3: Get Wireshark (www.wireshark.org)

  • Mac/PC/Linux – 32/64bit – Choose the version that is right for you.

Step 5: Choose where to place your tap

  • The tap will capture the traffic going between the two devices on either side of the tap.
  • Tapping the Externals will give you ALL devices on your network.
  • Tapping the Wireless AP will give you ONLY the devices connected wirelessly
  • Tapping a specific desktop/laptop/set-top box will give you ONLY that traffic
  • You choose if you want the outgoing or the incoming traffic.

Step 6: Capture

  • Press the button!
  • Choose the interface on your capture box. Typically it will be labeled "Local Area Connection"
  • Click "Start"

Step 7: Analyze

  1. Looking for Outgoing Streams: Are you a Spambot?
  2. Filter for SMTP: Look for SMTP packets when your computer is supposedly idle
  3. Filter for DNS: look for sites you don't recognize.
  1. Looking for "Top Talkers
  2. "Statistics" – "Conversations" – "IPv4"
  3. Click "Bytes" to sort by Top Talkers
  4. You can see the origin and destination of your traffic
  1. Looking for Usernames/Passwords in the clear
  2. In the "Filter" field, type " – "tcp contains username"
  3. This will give you all the packets that contain the string "username" in the clear
  1. Looking for Network Congestion
  2. tcp.analysis.retransmissions
  1. Here are a few helpful strings to get you started
  2. "ip.addr == 192.168.0.1: – This will give you all packets with 192.168.0.1 as either the source or destination.
  3. "ip.addr==192.168.0.1 && ip.addr==192.168.0.200" – This will give you all packets going between 192.168.0.1 and 192.168.0.200
  4. "tcp contains username" – This will display all TCP packets that contain the word "username" – I think the usefulness of this one is self-explanatory
  5. "tcp.analysis.retransmissions" – This will display all packet retransmissions – VERY useful when you've got a network that is unexpectedly slow.

Audio Calibration Part II with Scott Wilkinson

We've got part two of our audio calibration tutorial with Scott Wilkinson in this episode. In Part I of our audio calibration segment, we allowed the automatic calibration tool take care of our speakers. This time, Scott gives us the techniques we need to tweak our audio to create a great sound field.

Using a Sound Meter
Scott suggests that you pick up a sound level meter from a place like Radio Shack ($40-$50). You can also get an app for iOS or Android that can do the same thing.

AVR Settings
To calibrate your audio, set your sound meter to 70 dB. Then you'll place your sound meter on a tripod in the center of the room. Play the test tone from your audio/video receiver (AVR). Scott calibrates each speaker to 75 dB. To get even better audio, you can tell your AVR how far your seat is from each speaker. You'll need to take out the measuring tape and find out the distances. From there, you can place those values in your AVR.

If you cannot find your AVR's onscreen menu, you might want to connect your AVR to your TV via the composite (or yellow RCA) cable. Scott says that older AVRs feed their onscreen menus through that connection, which may seem counterintuitive to many.

You'll also tell your AVR if your speakers are large or small. The physical size of the speaker isn't what large or small refer to -- those words relate to what frequencies the speaker can reproduce.

Speakers and Subwoofer Tips
Any information that cannot be produced by a small speaker get redirected to the subwoofer. Scott's general recommendation is to tell your system that all your speakers are small. Don't worry about sending your low frequencies to your subwoofer because those low frequencies are non-directional. You'll hear what the director intended.

Where should you place your subwoofer? If you want to find the optimal place for your subwoofer, try the subwoofer crawl method. Place the subwoofer where your seat would be. Then play a familiar piece of music that has plenty of bass. Then crawl around the outside of the room. Wherever the music sounds the most natural is the place you should put your subwoofer.

When it comes to your audio cables, make sure you've got them set right; red to red, black to black. Mixing them up could lead to phase inversion, which causes indistinct audio.

The last step is finding the frequency below which you send audio to the subwoofer. This is also known as crossover. THX suggests 80 hertz. Scott suggests that you look at the specs of your speakers. If your surround speaker goes down to 100 hertz, Scott would set the crossover to 100 for all the speakers to create a consistent sound field.

Scott recommends that your five or seven speakers all come from the same manufacturer and possibly the same line. Individual manufacturers tune their speakers differently and to have a consistent sound from those speakers, it is easier to have speakers from the same manufacturer. Your subwoofer doesn't need to be from the same company.

Quickfire Questions

We got a chance to ask Scott four questions to get more information out the Home Theater Geek. We've given you a summary of the Q&A, but you'll have to watch the video or listen to the audio to find out the full answers.

1. Is there ever a reason to leave motion smoothing on?

Scott says yes, for things shot on video like sports or news.

2. Can you replace your speaker wire with coat hanger and not notice?

Scott said he wouldn't because the hanger isn't insulated nor is it flexible. Sonically, it might not be a problem.

3. Is there ever a good reason to place a TV over a fireplace?

No, the angle's all wrong.

4. Movie theater popcorn: lots of butter or light butter?

Neither. Scott doesn't eat popcorn.

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