Blog Changes And Audio Software

Hello, everyone.
This entry is somewhat an update, somewhat an informational blog entry. First, I'll begin with the update, which is rather short.

I have disabled user registration on my wordpress blog, as spammer bots have registered. I will be deleting the existing user accounts, so if you want one for some reason, send me an e-mail at blakeblind@gmail.com with your desired username and e-mail address. I will get to adding the account when I can. Since I'm now running Drupal, this no longer applies.

Now, the cool content.

I have recently been playing around with a program called Audio Hijack Pro, which, among other things, allows you to record audio from most applications and audio sources. It also lets you output your audio sources, say, your microphone from a headset, to speakers, headphones, or whatever you might have plugged in to your computer. You can also apply various effects to your audio, such as gain, compression, bandpass filters, and many others.

Most of the program is accessible to users using VoiceOver, the screen reader for Mac OS X. However, there is one part of the program that is annoyingly not accessible, though I've gotten around that issue by asking for sighted assistance. I will explain everything I know and can use about the program below.

The installation of Audio Hijack Pro is quite simple. The zip file can be downloaded by visiting Rogue Amoeba's download page for Audio Hijack Pro. As of this writing, the version available is 2.9.8, which fixes hijacking audio for users using Skype 5.

Once downloaded, do the following:

• Unzip the archive.
• Copy AudioHijackPro.app to your applications folder.

When you first launch the program, some sessions will have already been created, such as System Audio, and a few others I don't immediately know of. You will see these sessions in a table that is easily accessible. Below the table of sessions are various tabs laid out in a row. In order, they are:

1. Input
2. Schedule
3. Recording
4. Tags
5. Effects

The input tab allows you to select your source. You can select an application, audio device, System Audio, or a USB FM radio. If application is selected, you can select your source application. If Audio Device is selected, you can select both your input and output audio devices. If System Audio is selected, Audio Hijack will change your system audio device to SoundFlower (2ch), unless SoundFlower isn't installed. If it isn't on your Mac, you will have to install it before you can hijack system audio. It will then allow you to hear your audio through your default output device set at the time. The FM radio option I don't know much about, so I'll not cover it here.

I would like to stop describing Audio Hijack Pro for a moment, as I want to compare it to another application that is similar for Windows users. The application is called Virtual Audio Cable. It is different than Audio Hijack Pro, because it in itself doesn't let you record anything. It simply allows you to create virtual audio devices. Whatever goes in through these audio devices such as skype, will also be outputted through them, allowing you to record various applications as long as their output devices are configurable. In simpler terms, here is what you would do.

In Skype, you might go to tools, options, then click on Audio/Video, I believe is the option. Set skype's speakers to Virtual Audio Cable 1, then click save. You will no longer here anything through skype unless using Audio Repeater. I'm not going to go into too much detail, but I will tell you that Audio Repeater, which lets you take audio from an input source and play it through an output source, is more latent than Audio Hijack unless you wish to have audio breaking up a lot. You also must use multiple copies of Audio Repeater in order to perform complex audio routing tasks. Over all, Audio Hijack Pro is much better, as it has many features in the same program rather than using different programs for the same results.

There is one thing I want to note about Virtual Audio Cable, however. Since it allows you to create many virtual audio devices with a differing number of channels, you can perform quite complex audio routing tasks that are expandable beyond anything you might need. Soundflower, which is a driver with two different virtual audio devices for the Mac, is limited. You can't create multiple Soundflower devices, to my knowledge. You only have two. One with two channels, another with sixteen. While this is quite useful in itself, I've not seen in many applications where you can select what channels you wish to use for input, and what channels will be used for output. Therefore, Virtual Audio Cable has an advantage, though it's not Audio Hijack Pro that has the limitation. Its purpose is not to create audio devices, but rather, hijack them from an input to silence, or whatever output you want to use. That is similar to what Audio Repeater does, but since CoreAudio is used, it has a much lower latency time. Audio Repeater comes with Virtual Audio Cable, in case anyone was interested.

Anyway, I'd like to continue my brief description of Audio Hijack Pro, and will continue to compare it with the Windows applications as I go, where and if possible.

Once you have set your various options for a session in Audio Hijack Pro, you can begin Hijacking in one of two ways. You can press CMD+G, or click the Hijack check box in the toolbar above the session table. There is one thing I want to note about the advanced settings for audio. When you click the advanced button after selecting two audio devices, weather they be silence or actual devices, you can select the channel or channels you wish to use for both your input and output audio devices. You can also select the buffer time for both input and output, but this hasn't had any noticeable effect that I've noticed. This is quite useful for audio routing applications, especially when SoundFlower (16ch) is being used. To my knowledge, Audio Hijack Pro is the only audio application that allows you to select a specific audio channel or channels for use with input and output devices. You can't select more than two channels for input or output, though, something I wish you could do. At the same time, I understand why that isn't possible, but don't yet know how to explain it.

At the bottom of the Audio Hijack Pro window, you can create a new session, delete the session selected, or change the session options. For me, that button hasn't had any noticeable effect unless I click it rather than activate it. That, however, is a VoiceOver deal, which I won't go into yet. When the Session Options button is clicked, it pulls up a menu, allowing you to create a new session, delete or duplicate the currently selected session, or rename the currently selected session.

When you create a new session, application is selected as your source by default. You can change that option, however, as I explained near the beginning of this entry. On the toolbar, which is above the session table, you have the following options:

• Hijack

This is a check box, that when activated, will begin Hijacking. When deactivated, Hijacking will stop.

• Mute

This is also a check box. This will mute the audio you hear when you're hijacking, but won't deactivate any recordings being made.

• The hijack session name

This item is to the right of an unknown image, at least, that's what VoiceOver identifies what ever is to the left of that item. This isn't a changeable value unless you rename your session.

• Text Field Containing Duration Information

Below the name of the session is a field containing a duration. This is either how long Audio Hijack has been hijacking, or how long a recorded file is. When a recording is paused or you have set a silence threshold, the recording duration field won't change.

• Record

This is a check box. Like all the others, it toggles the state of your recording.

• Pause

This is also a toggling check box. When checked, your recording will be paused and whatever is being hijacked won't be recorded.

• Split

This is a button. It is only available when you're recording. Otherwise, it will be unavailable. This will allow you to split your recording by stopping the current file and beginning another.

Before you begin hijacking, there are various options you can set in the various tabs. The one I'd like to cover is the effects tab.

Unfortunately, the control VoiceOver identifies as a scroll bar is inaccessible, though it does contain a hole lot of fancy visual information that looks nice and is useful to those who can see. What is this information, you ask? I'll tell you what I see.

Empty Scroll Area.

Sometimes, if you're using VoiceOver, you can interact with that scroll area and press CTRL+OPT+SHIFT+SPACE, the hotkey that allows you to click on items. It may or may not pull up a menu, depending on weather or not your mouse is on the correct control. For me, it doesn't, so I can't use it without help.

I was able to get help, though, and set up a very nice Noise Gate with the Dynamics effect. I don't remember where that effect is located, though, so if you want to use it, you can look around. Alternatively, I can send you my effects patches that I made, which generally work well when using a headset.

Here is a brief overview of what I have my effects currently set at. From what I recall, these are the approximate values of the sliders.

• Noise Gate is active.
• Threshold is set somewhere around -40DB for the NoiseGate.
• I believe the attack slider is set at 0.05 or 0.1 seconds, again for the noise gate.
• I think the effects are the same for the compressor, with the exception of the attack slider, which I've put down as low as it'll go, I believe somewhere around 0.001 seconds or something like that. The compressor is also active.

I could be completely wrong, though, since I'm blind.

You will also see some level indicators, and a slider to adjust your gain. Usually, you will want to leave the master gain slider alone, as it likely won't help you.

There are many other options in the program, but I'm not going to go into them in this particular entry, not in text, anyway. You can download the audio demonstration of Audio Hijack Pro if you like, as I've now posted it on the blog entry.

Update: I have recently imported my blog entries from WordPress to my new site. I will re-upload the tutorial when I am able to do so.

Comments, questions, feel free to post them or send me an e-mail. Remember, your comments are moderated.

Have fun, folks!