The Swezey Digital Filter Program			June 15, 2014

Setup Instructions for Live Realtime Shortwave Listening

1. Connect an audio patch cord from the "Line Out" jack on your reciever to the "Line In" jack on your PC (Personal Computer) 's sound card.

Typically, a radio's audio output will be in mono and the sound card's input will be expecting stereo, you will want to use a Y-adapter in to make that conversion otherwise you may only hear sound on one side. These "mono-to-stereo" Y-adapters are commonly availiable at computer and electronics stores.

If your reciever does not have a designated "Line Out", you may be able to use the Earphone Jack output instead. If you do you will certainly want to set the volume level very low and increase it very slowly once the connections  have been established so as not to overload or damage your sound card.

WARNING! - I assume NO responsibility for any damages that may result from making the connection between your shortwave radio receiver and your PC. 

It is your responsibility to hook this up correctly. If you have any doubts about how to do this contact your receiver's or computer's manufacturer to find out how.

WARNING! - NEVER connect the output from the power amplitfier stage of a reciever (i.e. the speaker connections) to your sound card!  This can easily damage your PC's sound card!

2. You should be able to hear your shortwave radio through your computer's speakers.

There us no reason to continue until you can do this.

3. Start the Swezey Digital Filter Program.

On the "Welcome Window" click on "Agree" only if you agree to the conditons in the disclaimer here and the full disclaimer on my website at: 
http://www.winternet.com/~swezeyt/disclaimer.htm

If you do NOT agree - do NOT use this program!

4. On the "Preconfiguration Window" click on the "Preconfigure all settings for live realtime filtering (Shortwave Listening)" button and then click on the "Continue" button.

5. Next you will see the "I/O Configuration Window". 

As a result of step 4 you shouldn't need to change any of these settings - simply click "Enter".

Settings here can only be changed during program startup. 
Slower computers may require reducing the Sample Rate and FFT size to run in realtime.
Settings here are stored in "ini" files so you won't need to set them again.

Since Shortwave is always monaural don't select "Stereo" as it doubles the programs overhead.

"Pseudo Stereo Output" ("false" simulated stereo) is mostly useful for musical content. 
Since Shortwave is mostly voice you probably don't want it. It also increases the programs overhead.

For Shortwave Listening I recommend Sample Rate 44100 with FFT Size 1024.

If your computer has trouble running the program reduce the sample rate to 11025 and the FFT to 512.

Higher FFT give better results but require additional processing power..
FFT Size must be a power of 2 (i.e. 256, 512, 1024, 2048, 4096).
Large FFT Sizes may not run in real time depending on your computer.

You may "Hide" any of these screens to skip over them when you run the program in the future.
(You can always un-hide them later from the "Help" option on the Main Menu).

6. Listen. 

You should hear the filtered audio output from the program.
Toggling the "Disable Filtering" button on the "Mixer Control" should let you listen to either the live unfiltered input or the filtered output from the program.

Due to changes in Microsoft Vista and Windows7 and/or newer sound cards you may no longer  be able to use the program's built in "Mixer Control" "DisableFiltering" feature when you run the program.
You may need to select and control input and output on your computer manually.
You can tell this right away if you hear an "echo" in the sound from your receiver.

Normally, input on "Line In" is connected directly to your computer's speakers.

However, it is also input into this program where it is delayed slightly during processing and then output to the system's speakers. This will cause an echo.

The echo is the raw unfiltered input plus the delayed filtered program output.

The program is setup to select between the two streams via the 'Mixer Control' 'Disable Filtering' button. However, due to the growing complexity of sound cards I can't guarantee this is always done correctly. Sound cards vary greatly and you may have to do this manually.

If you end up needing to do this you may want to disable the programs attempt to control this by deselecting "Enable Swezey Mixer" on the "I/O Configuration Window".

The MS-Windows Volume Control "Mixer" Program

You can always use the MS-Windows Volume Control "Mixer" Program to set levels and select or mute what you hear.

You should find the Mixer at:: Start/Program/Accessories/Entertainment/Volume Control
or  Start/Program/Accessories/Multimedia/Volume Control

Sound cards vary greatly but typically the input source you want  has a name such as "Line-In" or a combined "Microphone/Line-In". It should be selected and it's level set up so it is not zero.

You can find this in the Mixer program by selecting "Options" on it's menu. Then select "Properties" and then select "Recording".

You also need to mute/un-mute "Line-In" under the "Playback" options to hear the live input.
Mute this when you don't want to hear the live input.

You can find this in the Mixer program by selecting "Options" on it's menu. Then select "Properties" and then select "Playback".

Also, typically the output from the program uses the source name "Wave Out".

You can find this in the Mixer program by selecting "Options" on it's menu. Then select "Properties" and then select "Playback".
Unmute this when you want to hear the program's filtered output.

Sometimes there is also a "Master Volume" and "Mute All" which need to be set correctly.

You willl need to be able to switch between "Line-In" and "Wave Out" to switch what you hear between the raw live input feed from your radio and the programs output. 

(One sound card I saw had a "Recording" feature called "Stereo Mix" which was recombining the program's output with the live input. I had to mute this when running the program).

Remember: the Demonstartion Version of the program has a periodic buzzing sound. There is nothing wrong with your PC.

My website is: http://www.winternet.com/~swezeyt/dsp.htm
Your comments are always welcome, please e-mail me at: swezeyt@winternet.com

Thank you for trying the Swezey Digital Filter Program!

(c) 2014, Thomas F. Swezey. All rights reserved. 06/15/2014)