This page is a response to the fact that I tend to get a lot of emails asking for advice on a variety of issues related to audio on a PC. If you are thinking of emailing me with a question, please check first to see if it's answered here.
Before we start, here is a list of subjects that I often get asked about, but of which I have little or no knowledge:
[This is a subject which has no relevance for me at present.
I work exclusively with WAV files and standard audio format CDRs.
However, here is a page about MP3
written by somebody who is clearly very enthusiastic. It seems to have
a great deal of useful information, although of course as somebody
who knows very little about MP3 I can't comment on it's accuracy.
And here is another page which
has links to a lot of MP3-related utilities.]
To make decent quality recordings, you must use the soundcard's line input;
the microphone input is generally of much poorer quality, and is mono on many
soundcards. Here is how to identify the line input:
On the back of most soundcards, you'll see three minijack sockets. (Most
soundcards also have additional multi-pin sockets which are used for things
like MIDI, but we can ignore these). These three minijacks are the microphone
input, line input, and line output. The sockets are colour-coded on some
soundcards, and generally the colours used are:
Having identified the line input, you need to feed it with an audio signal with
the appropriate electrical characteristics. This signal is called line level,
and is the signal level used by nearly all consumer audio equipment. Whether you're
using a tape deck, radio tuner, VCR, CD player, DVD player, satellite TV decoder,
etc, all these devices output a signal at line level. This means that you can connect
the output of such a device directly to the line input of a soundcard.
The execptions to the above are the following devices:
So, the signal that comes out of a magnetic cartridge has to be (i) boosted in
voltage, and (ii) adjusted to restore the correct tonal balance. Both of these
operations are carried out by a device called a phono preamplifier. In
order to connect your turntable to the soundcard's line input, you have to go
via a phono preamp. If you have a stereo receiver or amplifier which can accept
a turntable input, then it can be used as the phono preamp: connect the turntable
to the appropriate input on the receiver, and connect the receiver's tape record
output to the soundcard's line input. If you don't have a suitable input on a
receiver, you'll need to buy a phono preamp.
Having identified the output from your stereo that you wish to use, there is
now the problem of how to physically connect it to the soundcard. The soundcard's
line input will be a stereo minijack (ie. like a personal stereo's headphone socket).
Meanwhile, if you're using the tape record outputs from an amplifier they are likely
to be a pair a "phono sockets". A phono socket is about 6mm (1/4") in diameter,
with a small single central hole. The plug that fits this has a central pin with
an outer ring. You'll need to get a cable with a pair of phono plugs at one end and
a stereo minijack plug at the other. Most HiFi stores sell cables like this; they
are primarily designed to connect a personal stereo into a component HiFi system.
The fact that you'll be using it for recording rather than playback is immaterial.
There are two other types of output sockets you might be faced with:
If your receiver uses a 5-pin DIN socket for its tape output, it's unlikely that
you'll be able to get a cable with a 5-pin DIN plug on one end and a stereo minjack
on the other. In this case, you'll need to get a cable with a 5-pin DIN plug on one
end and phono plugs on the other. These tend to come in two varieties:
See here for a description of how to set up the soundcard so
it records from the line input.
Open up the Windows Volume Control utility. (This is usually
available by double-clicking the little yellow icon of a
loudspeaker in the system tray. If it's not there, go via
Start|Programs|Accessories|Multimedia, or perhaps
Start|Progams|Accessories|Entertainment). A screen titled
"Volume Control" appears. On this screen you will see a
selection of inputs. Each one can be individually switched
on or off using its "mute" checkbox. All those which are not
muted are available for playback through the soundcard's output,
and their relative volumes can be controlled using the appropriate
sliders. Thus, this screen behaves like a simple mixer, allowing
multiple sources to be gathered together for output.
OK, all this is fine, and allows you to pass the input through to
the output, but: it doesn't make the unmuted inputs available for
recording to hard disk. To do this, select the "Properties" item
from the "Options" menu. A screen titled "Properties" will appear.
In the box titled "Adjust volume for", there are radio buttons:
select the one for Recording. A list of available inputs appears
in the box beneath "Show the following volume controls", and you
should ensure that all the various inputs you may wish to record
are checked in that list. Now press "OK", and the main screen's
title changes to "Recording Control". This screen presents the
inputs available for recording, and to activate the one you want,
check its associated "Select" checkbox. The recording level can be
adjusted using the selected input's volume slider; note that you
can adjust this while recording (just like you can with the level
control on a tape deck). You may also see a simple level meter (like
the LEDs on a cassette deck) next to some inputs on some soundcards;
whether they appear depends on the particular facilities provided by
the soundcard's driver.
However, this meter is uncalibrated and most hard disk recording
packages are likely to have better metering. Once you have set
the required record level, you can close down the Volume Control
utility and the settings will remain unchanged.
One further tip. If you're recording anything other than the
microphone input, it is a good idea to mute the microphone on
the "Volume Control" screen whilst recording, as the microphone
input circuitry can add a fair bit of noise on many soundcards.
There is nothing that can be said about this except: don't try to
use compressed hard disk partitions for digital audio.
Some video cards, especially those which perform Windows acceleration,
obtain a small performance boost by not bothering to check if the bus
is free before attempting to use it. The result of this is that, if the
bus isn't free, then the video card tries to use it and blocks the bus,
resulting in audio samples getting lost.
A temporary solution might result from turning down the level of graphics
acceleration (in Win95/98, via My Computer | Properties | Performance |
Graphics).
The proper solution is to contact the video card manufacturer and find out
whether there is a way to configure its driver so that it always checks
that the bus is free before using it.
Programs lurking in the background which might spring into life at
inappropriate moments are to be avoided. Things such as screen savers,
email servers and the like should be switched off. One particular
program of this type is FindFast; if you have installed a recent
version of Microsoft Office it is probably on your system. The
problem with FindFast is that you never really know it's there
unless you take the trouble to check what tasks are running.
If you discover that it is running, kill it, and also remove it
from the Programs Menu Startup group (where it is likely to have
placed itself).
By default the Windows file system reads ahead, on the assumption
that the running program is soon likely to want the data that follows.
This is all very well for a typical PC performing a general mixture of
"normal" computer activity. It is, however, the last thing you need
while you're recording audio. Try reducing the amount of file system
read-ahead (via My Computer | Properties | Performance | File System).
If your recording software has facilities to adjust the buffering it uses
then it is worth experimenting with that. Some packages have a default
buffering strategy that is quite miserly. It costs nothing to increase
but a little memory, and most modern systems have plenty to spare.
I know of one person who had a problem with a continuous "ticking" type of
dropout during recording. He cured it by disabling 32-bit protected mode
disk drivers. You can do this via My Computer | Properties | Performance |
File System | Troubleshooting.
The Windows virtual cache is quite often the culprit when occasional
(rather than constant) dropouts are experienced. That said, it is
probably better to eliminate other possibilities first, since to adjust
the vcache requires that you edit the SYSTEM.INI file rather than just
adjust some settings.
If the vcache is allowed to change in size, it'll be just your luck
that it does so in the middle of an important recording, with a consequent
loss of samples. The trick is to set the vcache up with the same settings
for its minimum and maximum size, thereby stopping Windows ever resizing it.
To do this, you need to edit the file SYSTEM.INI in the Windows system
directory (usually C:\WINDOWS). Open the file with any text editor
(eg. Notepad) and find the section headed [vcache]. Add two lines beneath,
so that the section looks like this:
If your soundcard attempts to use the same IRQ as another device, anything
can happen. If all your devices are plug-and-play, it is easy to check that
there are no conflicts by going through each device under My Computer |
Properties | Device Manager. If you have any non-plug-and-play cards,
they must be set up manually to avoid conflicts. Moreover, you must also
instruct the BIOS to prevent allowing the IRQs used by those non-plug-and-play
cards to be assigned to plug-and-play cards. To do this, it is necessary to
enter the BIOS setup during PC bootup, find the place where IRQ assignments
are made, and set those IRQs being used by non-plug-and-play cards to the
appropriate value (often called something like "ISA", or "N/A", or "Legacy").
Although unlikely, it is possible that the drivers for your soundcard have
some kind of incompatibility with the timing of your main system board.
Modern PCs are less likely to have this problem; it was more an issue with
old ISA bus 386 and 486 machines. Nevertheless, you should make sure you
have the latest drivers for your soundcard.
In these days of Ultra-ATA and SCSI hard disks, fragmentation is rarely an
issue. Modern hard disks are so fast that the data rates required by simple
stereo audio is no problem unless there is an extreme degree of fragmentation.
However, occasionally defragmenting your hard drive can't hurt, so it's worth
doing it now and again.
The other possibility is that you have accidentally plugged into the soundcard's
microphone input (some mic inputs are mono), although in most cases feeding a line
level signal into a mic input causes serious overload distortion.
When a CD is burned in TAO mode, the laser is switched off between
each track, and by default this causes a gap (usually 2 seconds) between
the tracks. Some CDR drives allow this gap to be adjusted, and some CDR writing
software allows you to set the gap if the hardware supports it. In extreme
cases it may be possible to set to inter-track gap to 0. Whether this achieves
what you want depends on the hardware's ability to pick up precisely where it
left off, and in most cases even with a gap of 0, there will be a tiny but
noticable "tick" between the tracks.
To get the desired effect of multiple tracks with no gap whatsoever between
them, it is usually necessary (and certainly more reliable) to burn the CD
in DAO mode. Here, the entire CD is written in one go, without the laser being
turned off at any stage. The disadvantage of doing it this way is that you
can't build up your CDR in steps; you have to have all the tracks
prepared and ready on hard disk so the whole disk can be written.
There are two ways to get the track positions in the right place when burning
in DAO mode. Which one you need to use depends on the way your CDR writing
software works:
So, if you want to make a CDR with these "countdowns", you must place index 0's at
the appropriate places. Many CD writing packages don't have the ability to do this,
but two I know of that can are CDRWin and CD Architect.
A hidden track before the start of a CD (the type where you must start playing track
1, then search backwards to get to it) is simply music placed in index 0 of track 1.
When a CD player begins playing the disc it starts at index 1 of track 1, so
the hidden part doesn't normally get played.
How do I connect my stereo to the PC?
This section discusses (and tries to describe) various types of connectors and other devices.
If you are unsure what the connectors are, here are some pictures (please note
that where a scale is shown, it is a ruler marked in centimetres and millimetres):
You need a soundcard in your PC which is capable of recording in CD format
(which is 44.1kHz, 16 bit, stereo). All modern soundcards are capable of this.
This section will assume that you're using a mainstream soundcard
(such as one of the Soundblaster or Turtle Beach range) that has stereo minijack
connectors. (A stereo minijack socket is the same as the
headphone socket on a personal stereo).
If you have a more sophisticated soundcard with phono, 1/4" jack, or
XLR sockets, you should already know know what you're doing.
However, this is by no means
certain. Quite often there is a small picture next to each socket, either printed
or engraved. One of these pictures is supposed to look like a microphone, but I
think often looks more like an ice-cream cone; this is the microphone input.
The other two pictures have a set of concentric circles; the one with an arrow
pointing towards the centre of the circles is the line input, and the one
where the arrow points out from the centre is the line output.
You are very strongly advised to use the tape record output from your receiver
to feed the soundcard. If you have an integrated stereo system which has no tape
record output sockets, then you will probably have to use the headphone output.
Some integrated systems have a pair of sockets marked "aux" or "auxilliary". These
are almost certainly inputs, not outputs, so they will not be suitable.
Once you've got the stereo connected to the soundcard, you'll now need to make sure
that your PC is ready to record from the correct input (ie. the line input). Most
PCs are set up by default to record from the microphone input, and if you go ahead and
try to record something without changing this, it's likely that all you'll end up
with is a recording of the background noise of the microphone input circuitry.
Then, using small adaptors which allow phono plugs to be
connected back-to-back, use the phono-to-minijack cable described above to complete
the connection to the soundcard.
How do I record from cassette tape to hard disk?
You will probably need a cable with two phono plugs on one end and
a stereo mini-jack on the other. Phono plugs (also known as RCA plugs
or Cinch plugs) have a thin centre pin and a surrounding ring about
1/4" (6mm) diameter. Stereo mini-jacks look like the plug on a pair
of headphones used with a Walkman. Most audio stores sell cables like
this; they are primarily designed to connect the output of a Walkman
into a home stereo system.
If you intend to write the results to a CDR, use WAV format, 16bit,
stereo, 44.1kHz. Some recording packages describe this as "CD Quality".
I can play through the computer speakers,
but can't record to hard disk
There is a difference between which inputs are made available to
the soundcard's output, and which one is made available for recording.
I'm getting dropouts during recording to hard disk
There are a host of possible reasons for anomolies during recording.
Most of them are system configuration issues, and they are discussed
here in the order that you should investigate them, not necessarily
because the earlier ones are more likely to be the cause, but because
they are easier to check and/or correct. Remember that after making
any Windows system configuration changes it is necessary to reboot
the PC before they take effect.
[vcache]
MinFileCache=4096
MaxFileCache=4096
If there is no [vcache] section, add one at the bottom of the file.
If the existing [vcache] section already has settings for MinFileCache
and MaxFileCache, adjust them accordingly. The actual value to use
(4096 in the example above) is the size in kilobytes of the cache.
4096 (ie. 4MB) is appropriate for a PC with about 32MB of main RAM.
Generally about 1/8th of the main RAM is a suitable amount to use,
but if you have more than 64MB of main RAM, it probably isn't worth
setting your vcache above 8192.
When I record to hard disk I'm only getting one channel
This is most often caused by using a mono minijack. (Here
are pictures of mono and stereo mini-jacks). A soundcard's line input
is a stereo minijack socket. It is easy to recognise the difference between
mono and stereo minijacks: a mono minijack has one thin plastic ring near the
tip of the connector, whereas a stereo one has two plastic rings.
How do I burn an audio CD with multiple tracks but
no gaps between the tracks?
There are two basic ways to burn an audio CD. These are known as
"Track at Once" (TAO) and "Disc at Once" (DAO).
How do I create a CD with "countdowns" between tracks?
Every track on a CD can have multiple indexes, but must have at least
index 1, which is where the CD player starts playing the track if you skip to it.
If the track also has an index 0 preceding index 1, then when the CD player
passes this point, it increments the track number and starts counting down; when it
gets to index 1, the countdown is complete and the display starts counting up again.
How do I put "hidden" music before the first track on a CD?
(First, read the preceding topic which explains the significance
of index 0 on a track).