All glories to Sri Guru and Sri Gauranga

Tips for Recording Audio
and preparing for the Web

Last updated after receiving your feedback, and after gaining some painful experience: 15 December 2005. Please see the update re using an iPod to record.

Mini-discs have proven very good for recording, the quality of recording being excellent, but they have also proven to be particularly delicate. Mini-disc recorders work very well as a pre-amp for recording directly into the computer (Macs need a pre-amp, PCs may not need one). A regular cassette recorder also works as a pre-amp, though it is likely to introduce background hiss.

Recording directly into a Macintosh computer has proven in our experience to be the safest way of high quality digital recording.

iPods are becoming quickly popular, but please read the cautions concerning recording with them.

Flash memory recorders have recently come on the market. We have very limited experience with these, though so far they have proven reliable.

Whatever you use to record, always experiment first to test the results.

Basic recording tips:
-) use an external microphone so as not to pick up the sound of the recorder's motor;
-) turn off the 'beep' on the recorder if it has one;
-) use new heavy duty batteries (not rechargeables, they've proved inconsistent in performance) in the recorder and in the microphone (where applicable);
-) use a disc with sufficient space;
-) ensure the microphone is turned on and plugged into the correct socket;
-) visibly check the input volume meter to ensure it is indeed receiving audio input, and audibly check that all is well;
-) ensure the time is passing by on the 'recorded time' clock, i.e. that it's not on 'pause;'
-) while recording, regularly monitor the battery level and the record time available.
-) don't move the recorder or wires during recording.

Better recording for lectures:
-) use a 'unidirectional' microphone;
-) change the Recording Mode on the mini-disc recorder to 'Manual,' this prevents the recorder from 'seeking' during times of silence. And set the recording level so it doesn't go above the maximum input level;
-) position the microphone slightly to one side of the speaker and use a foam cover, this helps avoid it picking up aspiration of the letter 'p,' etc.
-) if you are sending an audio dispatch, try to be consistent with microphone position, distance, and other settings. Thus if you wish to add something later, the sound is more likely to be similar.

Helpful:
-) on the mini-disc recorder, set 'Time Mark' to '5 minutes.' This makes it easier to navigate if needed later;
-) on the mini-disc recorder, set 'Display' to 'Record time remaining.'

Take an audio cable with a male jack on each end, plug one end into the earphone socket of the minidisc player, and one into the line-in on the computer. (Some computers don't have a 'Line-in' but do have the facility to record with the USB port via an adapter.) Then:

-) (on a Mac) ensure your Control Panels / Sound / Input is set to 'Line-in' and 'Play sound through output device;' and while in the Sound control panel, turn OFF the Alert sound;
-) turn OFF virtual memory;
-) open appropriate sound software. (UltraRecorder is simple and efficient.)
-) ensure 'auto gain' is turned OFF (otherwise it 'seeks' during periods of silence);
-) ensure settings are: 44.1 KHz, 16 bit, No compression. Normally mono is sufficient for speech, especially if the file is intended for the web;
-) ensure the mini-disc player isn't set to boost the base, etc.
-) start playing the sound source (the mini-disc player, cassette player, etc.) and check there's an input sound wave;
-) adjust the 'volume' of the mini-disc player and the 'gain' of the software so as to prevent the input volume from exceeding the maximum input level.
-) listen! Check there's no electrical interference (some appliances and neon lights can introduce a hum). Make a 1 minute test recording and listen to that too.
-) When all is confirmed to be working well, then start recording from the beginning. Don't use the computer for anything else during recording.

Be careful:
-) we have experience on different computers that if you're using a Mac running System 9.2, in general you may experience moments where the mouse appears to freeze for a few seconds, if so, you will almost certainly lose parts of audio during transfer. To avoid this, go to Control Panels / Extensions Manager: save your current set, then make a new set using the 'Mac OS Base' setting and restart the Mac.

A Mac needs a pre-amp to boost the input of a regular microphone. Special microphones are available, and adapters are available, but a minidisc player works very well:

-) Set up the minidisc recorder ready to record and ready to transfer to the computer as given in the steps above.
-) Then simply put the minidisk recorder in the 'Record' mode and Pause it. The microphone input is then amplified and fed directly to the computer. In this paused state, the minidisc player uses very little power from its battery, and runs for several hours.
-) But be careful the mini-disc player isn't set to boost the base, etc.

If you are preparing audio (or anything, for that matter) for the public, then it needs to be presentable. It is necessary to review sound files before publishing, and where necessary to do some basic removal of excessive hesitations, repetitions, mistakes, intrusive sounds, etc.

-) Make a copy of the sound track.
-) Convert it to 44.1Khz mono 'aif' format (or on a PC: 'wav')
-) Using Peak, Sound Edit, or similar sound editing programme, listen to the track, cutting out anything that shouldn't be there. (Casual conversation, mistakes, phone calls, excessive 'mmmmm's' etc.). Save(!).
-) If your software has the option, ensure both 'Blending' and 'Snap to Zero' are on.
-) Be careful while editing, and always listen to any cuts so as to prevent surprises.
-) Make the track as loud as possible without 'clipping.' Clipping is distortion due to being too loud. In Peak it's in DSP/Gain then click 'clip-guard.'
-) Save the final file, and keep a copy safely. Make a CD quality mp3 file from this for archiving.
-) Putting a high-pass filter with a frequency of 120-160 Hz on the audio helps with the occasional rumble from breath/wind.

-) Slice up the lecture into approx. 15 to 20 minute sections, selecting appropriate places. Copy each section and paste into a new mono track.
-) Keep less than 1 second of background sound at the beginning, and fade it in; and 3 seconds of background sound at the end of each track, and fade it out. Then add an additional 4 seconds of silence at the end of each track. (Otherwise in conversion to mp3 some words may be lost.) Save.
-) Then convert them to mp3 files. To make files as a reasonable compromise of size vs quality for the web, set the Preferences to 16 or 24 kbps mono. That's done in iTunes by: Edit / Preferences / Advanced / Importing. Set Bit Rate to Mono 16 (or 24) kbps, and Channels to Mono. Click OK. In SoundJam it's done directly in the 'Converter' window. Converting in iTunes is done by: Advanced/Convert then select the tracks.
-) Check the final quality.
-) At this stage, drag the final tracks into an mp3 converter such as SoundJam, iTunes, etc. Then 'Edit / Get Info' and adjust the names in the 'Tags' appropriately.
-) Ensure the file name uses only numbers, regular non-accented letters, hyphens and underscores and no spaces.
-) and that the name of the file has the extension (i.e. ends with): .mp3
-) Upload them, or attach to an email to us, and let the world be nourished.....
-) Playlists for mp3 files (and some other formats too) can be made by listing the absolute URL separated by carriage returns in a plain text document, then putting the extension '.m3u' at the end of the file name.

This is only for the adventurous. Many radio stations use this format. RealMedia files start to play almost immediately as long as the receiving computer has the free RealPlayer or RealOne installed. There is a bit of a trick to make it all work:

-) The files are made by converting the prepared AIF files using the free programme 'RealProducer Basic' available on the web from
http://www.realnetworks.com
-) in general for talks, use the settings:
     Single Rate; Music; 28 K Modem
and click 'Start.' This produces the actual sound file (with .rm extension)
-) The trick comes in producing the required Ram file that points to the audio '.rm' file. The official version (but see the next paragraph below) says it has to be both made and uploaded using the RealProducer programme. After creating the .rm file (in the last step):

Then Tools / Create Web page (this additionally creates a local Ram file)
Then Tools / Publish Web page (this does a particular adaptation of the local Ram file for it's appropriate place on the web.)

However, a regular text file seems to work just as well. It's a simple text file containing only the full URL of the .rm file. Remember to give it the extension (last characters): Ram

It is this Ram file you'll need to link to from your webpage for simulated streaming. If you want that the .rm file can be downloaded, then you'll need to make a separate link to the .rm file.
Multiple RealMedia files can be linked together for simulated streaming simply by adding more URLs to the Ram file, each one separated by a carriage return.

-) If you don't have your own web-space to upload files to, you may send to us as email attachments.

-) Pasting the URL of a .mp3 file into QuickTime Player or Windows Media player will play almost immediately that file.

-) Pasting the URL of the .rm file into RealPlayer or RealOne Player will play almost immediately that file.

iPod warning. First, is worth repeating that unless you've installed Linux please don't use an 'iPod' to record classes or kirttan (or unless you have one of the latest models that record with the supplied software, see below). If you have no other option, then at least ensure the recording level is very low (it can be amplified later on a computer). It distorts all sound, but it distorts loud sounds in a particularly ugly way.
Although these hi-tech, expensive iPod machines are good at playing audio, they make no claim to be good at recording. Indeed their native software (until the recently, at least) is very poor at recording (for the technical minded: it records at a sample rate of only 8 kHz). A cheap cassette recorder works better.

However reasonable quality recording is now possible on some iPods by installing Linux on the iPod. The procedure to install Linux is given in the MacWorld article: The Linux iPod - Geek factor. If you don't do this, then please *don't* use your iPod to record anything important.

For 4th generation iPods, the Linux installer is available at: http://kainjow.com.
It is unsupported but is reported to work fairly well, to include a battery level meter and it doesn't dump the whole file if the battery runs out.

The latest models (as of October 2005) do indeed record at reasonable quality using the native Apple software without resorting to the Linux workaround (check the specs before purchasing).

BUT, if recording using an iPod please note the following:
The newly discovered drawbacks with the two machines we've used here are (and it's been pointed out that apparently not all models suffer these drawbacks, so all the more reason to check the characteristics of the machine you use or propose to buy):

-) heavy battery usage while recording (45 to 60 minutes recording with fully charged battery);
-) no functioning battery monitor in Linux mode, so there is no way to check the battery status at any time, and no warning before the battery dies;
-) and if the battery runs out, the whole file is lost;
-) in Linux mode the iPod doesn't go to sleep, so it always uses some battery power even when not in use.

On the positive side, the iPod does record while connected to the power-source, and if the power goes off (a definite consideration here in India), it continues recording using its internal battery without interruption (and, thankfully, without dumping what it has recorded so far).

Another solution may be this: an external battery that overrides the internal battery. Such a battery is made by Battery Technology, and is available for third generation iPods: http://www.batterytech.com/ipod_info/iPod_info.htm.  

A second iPod caution. Our experience here in India is that, in the short time we've been using iPods to record, we have already had them generate three corrupted files (also reported by others). Quite why this is, is not yet sure. But it would seem worth using a second recording method as backup in the meantime.
With some trial and error, the uncorrupted part of the file may be transferred to the computer by playing the audio out of the iPod, and recording through the line-in of the computer. In our experience a significant part of the audio of each corrupted file was lost.