Fullscreen HTML5Med Res (??MB)HTML4

LP Resurrection How to transfer LPs & tapes to CD Dust off your old collection of LPs and tapes! If you have a CD writer, you can transfer some of them to CDs and even clean up the sound in the process. It’s easy to do and doesn’t cost the earth. I F YOU’RE OVER 30, you probably have a large collection of LP records and cassette tapes. It’s also probable that you no longer listen to them, mainly because CDs are easier to use and have better sound quality. Few people these days can be bothered trying to maintain a record By GREG SWAIN player in good nick. Nor can they be bothered with the cleaning rigmarole that goes with vinyl LPs, to keep dust and lint from clogging the stylus and degrading the sound quality. Inevitably though, there are lots of “old favourites” scat­tered through our LP collections. And despite their inherent limitations, LPs are still capable of producing excellent sound quality – provided they’re not too worn and the record player and pickup stylus are in good nick. For this reason, it makes a lot of sense to transfer some of those old favourites to CDs. These are not only much more con­venient to play but can be used in a car CD player as well. What’s more, the sound quality is “locked in” to the CDs and your LPs are protected from further wear. What’s required CD writer prices have tumbled over the last two years, so burning your own CDs is now very affordable – assuming you have the right equipment. The inventory reads like this: a turntable (or tape deck), a phono preamplifier, the right connecting ca­ b les, audio recording software, and a Pentium-based (or equival­ ent) PC equipped with a CD writer, a decent sound card and lots of hard disk space. The sound card is a critical element here because it’s used to convert the analog signal from your LPs to digital format. This means that the sound quality will depend on the card’s on-board A/D (analog-to-digital) converter. Don’t expect to get good results from an old Sound Blaster 16 or any of the cheaper cards of that era. 4  Silicon Chip Fig.1: the turntable output must be fed to the line input socket of the sound card via a phono preamplifier, as shown here. Most recent brand-name sound cards should provide good re­sults, however. These include Sound Blaster 64 and Sound Blaster Live, plus sound cards from Diamond (eg, Diamond Monster Sound), Turtle Beach and CrystaLake. Conversely, the CD writer is not critical and all brands should give similar results. It’s the quality of the digitised audio on your hard disk that you have to worry about – not the CD writer itself. By the way, if you’re buying new, go for a CD-RW drive so that you can also use the new re-writable CDs. The write speed of the drive isn’t critical but try to choose one with a read speed of 24x or better. An IDE drive will be cheaper than a SCSI drive but note that your PC’s motherboard must have a reasonably fast IDE interface. The record player The record player (or turntable) really is a vital link in the chain. Examine it carefully – the stylus should be in good condition, all the controls should operate smoothly and there should be no audible “wow” and “flutter” (ie, pitch variations due to turn­table speed variations). If the turntable speed varies as a record is played, check the condition of the belt or idler wheel. These rubber parts deteriorate over time and may require replacement. Check also that the tonearm operates freely and that the tracking weight and anti-skating settings are correct. The turntable speed should be accurately set using a stroboscope disc, if you have one. If the player hasn’t been used for some time, it will prob­ably need a good clean up. Depending on the brand, you may also want to apply some machine oil to the moving parts of the mechan­ ism underneath the platter, to make sure it all operates correct­ly. Don’t hesitate to replace the stylus if it’s worn or coated with gunk (examine it under a magnifying glass). Replacement styli and cartridges are readily available from hifi stores and from Tandy Electronics. New record players are also readily available and at quite reasonable prices. For example, Tandy Electronics has a fully-automatic belt-drive turntable for less than $200.00. This unit even includes a switchable phono preamplifier, which means that you can couple it directly to the auxiliary input of an amplifier (or even directly to the line input of your sound card). Connecting it up As already mentioned, the sound card digitises the analog audio that comes from the turntable. However, you can’t directly connect the turntable to the sound card. Instead, the turntable’s output must first be fed to a phono preamplifier, which amplifies the weak signals from the pick-up cartridge. During this process, the phono preamp equalises the signal Fig.2: this is the setup for an integrated amplifier with an inbuilt phono preamp. The sound card goes in the tape loop of the amplifier. January 2001  5 Fig.3: here’s how to set the Play and record line levels of the sound card. Any unused inputs should either be muted or not selected, to prevent unwanted noise. by boosting the bass and cutting the treble frequencies. This is necessary because LPs are recorded with the bass frequencies heavily attenuated, while the treble frequencies are boosted. The phono preamp reverses this situation, to give Fig.4: when recording for CD, you should sample at 44.1kHz and choose 16-bit stereo sound. a level frequency response (hence the term “equal­isation”). In most cases, it’s just a matter of feeding the turntable outputs into the “Phono” inputs of a stereo amplifier (or pream­plifier). The “Tape Out” or preamp out signals are then fed into the line input socket of the sound card – see Fig.2. Alternatively, you can use a separate phono preamplifier (eg, as described SILICON CHIP, April 1994). The output from this is then fed into the sound card as shown in Fig.1. Of course, if your turntable includes a phono preamplifier (eg, the Tandy unit noted above), then you can go direct to the sound card. Another option is to build the “LP Doctor” project de­scribed in the current issue. This not only has the necessary stereo phono preamplifier but also includes circuitry to filter out clicks and pops. It can be used for cleaning up the sound before it goes to your sound card, or you can simply use it with your hifi system. An audio cable with two RCA plugs at one end and a stereo 3.5mm jack plug at the other will usually be required to make the connection from the preamplifier. The RCA plugs go to the left and right output sockets on the preamp, while the 3.5mm plug goes to the line input socket on the sound card. These cables are readily available from electronics retail­ers for a few dollars. Alternatively, you can buy a cable with a 3.5mm plug and two RCA sockets, if that is what you require. If you don’t have “Tape Out” sockets on your amplifier, try taking the output from the headphone socket. In that case, you may need to use a cable with 3.5mm stereo plugs on either end and possibly also a 3.5mm to 6.5mm adapter for the headphone socket. Note, however, that the signal level from a headphone socket varies in response to the volume control setting. This means that you’ll have to carefully adjust the line-in gain of the sound card using the volume control panel on the PC, to prev­ent signal overload (Fig.3). What if you’re using a cassette recorder? In this case, the output is already at line level, which means that you can feed the output signal directly into the line input socket of the sound card. Monitoring the sound Fig.5: CoolEdit 2000 comes with an array of filters for noise reduction and other special effects that let you “operate” on the recorded sound. 6  Silicon Chip To complete the setup, you need some way of monitoring the music that’s being recorded. If you’re using a separate phono preamp, simply Looking for a top-notch sound card with lots of bundled software? Creative’s Sound Blaster Live Platinum provides Dolby Digital 5.1 surround sound and includes a microphone, a remote control unit and a device called “Live! Drive IR”. The latter functions as the IR receiver and also provides a range of front panel inputs so that external devices can be easily connected. The bundled software includes Sound Forge 4.5 XP, Creative PlayCenter 2 for encoding and decoding MPS and WMA files, and Creative Media RingTalk for PC-to-PC voice calls and messaging over the Internet. connect the sound card’s line output to a line input on a separate amplifier (eg, to an auxiliary or tuner input), as shown in Fig.1. As before, you’ll need a cable with a 3.5mm stereo plug on one end and two RCA plugs on the other. Alternatively, if the phono preamp is integrated into the amplifier, you’ll need to connect the sound card’s output to the tape monitor input of the amplifier – see Fig.2. In other words, the sound card is effectively connected into the tape loop of the stereo amplifier. Stopping noise pickup Computer monitors can easily induce noise into sensitive audio equipment, so position your monitor as far away from the rest of the gear as possible. This particularly applies to the turntable – the pickup cartridge can be rather sensitive to stray electromagnetic fields. If hum still proves to be a problem, try earthing the base of the turntable directly to the metal case of the preampli­fier. Another tip is to plug everything into the same power point (via a multiple socket strip) to reduce the possibility of hum due to earth loops. Naturally, you must use shielded audio cable for all con­nections between the turntable, preamplifier and sound card. Cleaning the records To minimise surface noise, it’s vital that you thoroughly clean your LPs. A soft bristle brush and some warm Creative’s sound card includes all the usual inputs and outputs on the backplane connector, plus onboard connectors for CD-ROM and DVD drives and for the Live! Drive IR unit. January 2001  7 Fig.6: the Audio Cleanup Plug-In for CoolEdit includes filters for click and pop removal, for hiss reduction and for clip restoration. You can either use one of the presets or tailor the filter to requirements. water can be used to remove any dirt that may have found its way into the grooves. Be careful not to damage the LP – brush carefully in the direction of the grooves and don’t scrub too hard. Don’t use a detergent, as this can leave a film residue on the surface of the LP. An antistatic cloth and a record cleaning brush will also come in handy. Once again, these are available from hifi stores and electronics retailers. Getting ready An audio CD accepts about 650Mb of data, so you’ll need to set aside plenty of hard disk space when making audio recordings. As a minimum you will need about 1Gb but 1.5Gb is better. Basically, there are five steps involved in transferring the material across: (1) select the line input of the Fig.7: CoolEdit’s dynamic noise reduction filter works by loading a noise profile – usually sampled from the beginning or end of a track – and subtracting this from the rest of the recording. sound card and set the signal level; (2) record and save the LP tracks to the hard disk (in wav format) using suitable recording software; (3) process the audio to reduce noise or to apply special ef­ fects; (4) assemble the tracks in order using CD writer software; and (5) burn the CD. Of these, step 3 can be regarded as optional, particularly if you’re getting good sound straight off your LPs. If that’s the case, you’re probably better off not applying any filtering at all to avoid any impact on the music. Conversely, LPs that are worn or scratched will need to have some filtering applied (and perhaps some other pro­cessing as well), depending on the type of material and the severity of the problem. Before trying to record anything, you need to turn up the gain controls for the line input of the sound card. You do that by first double-clicking Fig.8: CoolEdit’s graphic equaliser comes with a number of presets for changing the sound, or you can adjust the sliders yourself. 8  Silicon Chip the loudspeaker icon in the system tray (at the end of the taskbar) to bring up the “Play Control” mixer panel (Fig.4). Make sure that the Play Control (master), Wave and Line-In are not muted and that their volume sliders are turned well up so that you can monitor the sound. Next, click Options, Properties, Recording and OK to bring up the “Record Control” dialog box. Select Line-In and again make sure its volume slider is well up the scale. It’s a good idea to mute the other inputs and outputs (CD Audio, MIDI, etc), so that they cannot add to the noise. Recording software It’s the job of the recording software to set the sampling rate for the incoming audio signal and to save the recorded file to the hard disk. There are lots of programs available and these invariably include level indicators and controls to play, record, stop and (sometimes) pause the audio. What’s more, many programs include a staggering array of filters and effects that let you tailor the sound to your tastes. Want more bass? No problem – just load the bass-boost filter or a graphic equaliser. What about some treble cut, or a 50Hz notch filter, or some reverberation or flanger effects? They’re all there for you to try. Want to filter clicks and pops, reduce surface noise or cut tape hiss? There are filters to do these jobs as Fig.9: if your recording needs a bit more bass, CoolEdit’s FFT filter can take care of that too. well. You can even copy, cut and paste sections of the recordings to produce special effects if you want. A popular software choice is Adaptec’s Easy CD Creator 4 Deluxe which features a utility called “CD Spin Doctor”. CD Spin Doctor can perform all the basic tasks required to transfer LPs to CD, including the ability to save audio files in the required wav format. It can also perform fades and includes some basic filtering software to reduce pops, clicks and hiss. If you want something a bit fancier, consider programs like Syntrillium’s Cool Edit 2000 and Sonic Foundry’s Sound Forge 4.5 XP. Trial copies of these programs (and other programs mentioned in this article) can be downloaded from their respective websites (see panel). One program that’s easy to drive and doesn’t cost the earth is Diamond Cut’s Audio Restoration Tools – either DC-Art or the better-featured DC-Art32. The latter features a comprehensive array of filters and special effects and is certainly very effec­tive when it comes to getting rid of clicks. An alternative package is Dart PRO 32 from Digital Audio Restoration Technology However, if you’re into serious audio restoration and want the very best results, you’ll need to step up to the “Diamond Cut Millennium” package which can simultaneously run multiple filters for fast audio processing. Another package in the same league is Dart PRO 98 but you’ll Fig.10: the FFT filter is also handy for filtering out 50Hz and 100Hz hum. And there are lots of other filters to try. need to be serious – these packages retail for around $450.00 and $500.00 respectively. Making the recording Whichever program you use, the act of recording LP tracks and saving them to disk is a straightforward exercise. Usually, the first thing that you have to do is set the sampling rate. To record CD stereo sound, you’ll need to choose 16-bit stereo and sample at 44.1kHz – see Fig.4. The next job is to set the recording level. All decent audio-recording programs come with sound level meters and you have to adjust the line level control (Fig.3) while a record is playing but with the recording paused. Basically, the level is set so that the left and right channel signal peaks just fall short of activating the overload indicators. Anything more than that and you run the risk of introducing distortion due to clipping. On the other hand, don’t set the level too low as this will give a poor signalto-noise ratio. Don’t let any nasty clicks and pops fool you into turning the gain down too far. It’s OK for these to trigger the overload indicators as they can be filtered out later. Once the level has been set, it’s just a matter of clicking the record button to start the recording. Before doing that though, make sure that you’ve turned off your screen saver. If a screen saver activates in the middle of a recording, it can leave a gap in the music. Generally, it’s best to record each track in turn and save it as a separate file. This not only cuts down on individual file sizes but makes it far easier to edit the tracks later on. The way in which you go about this is up to you. However, the easiest method is to simply lower the stylus onto the lead-in grooves of the track What About Copyright? Many LPs and tapes are still protected by copyright and, as far as we can determine, you are not entitled to copy these to other media – not even for your own use. That even applies to LPs and tapes that you have paid for and which are your personal property. Of course, you are at perfect liberty to copy material if there is no copyright, or if the copyright has expired, or if permission has been obtained from the copyright holder. In addition, there can be exceptions under the Copyright Act for educational and professional bodies. By contrast, consumers in the United States have had the right to copy music they have purchased to other media for personal use, ever since the Home Recording Act of 1992. It seems that Australian copyright law is behind the times in this regard. January 2001  9 P.C.B. Makers ! • • • • • • • • If you need: P.C.B. High Speed Drill 3M Scotchmark Laser Labels P.C.B. Material – Negative or Positive acting Light Box – Single or Double Sided – Large or Small Etch Tank – Bubble Electronic Components and Equipment for TAFEs, Colleges and Schools Prompt and Economical Delivery FREE ADVICE ON ANY OF OUR PRODUCTS FROM DEDICATED PEOPLE WITH HANDS-ON EXPERIENCE We now stock Hawera Carbide Tool Bits KALEX 40 Wallis Ave E. Ivanhoe 3079 Ph (03) 9497 3422 FAX (03) 9499 2381 ALL MAJOR CREDIT CARDS ACCEPTED Silicon Chip Binders REAL VALUE AT $12.95 PLUS P&P  Heavy board covers with 2-tone green vinyl covering  Each binder holds up to 14 issues  SILICON CHIP logo printed on spine & cover Price: $A12.95 plus $A5 p&p each (Australia only) Just fill in & mail the handy order form in this issue; or fax (02) 9979 6503; or ring (02) 9979 5644 & quote your credit card number. 10  Silicon Chip Typical of the CD rewriters that are now available, Creative’s CD-RW Blaster 121032 can burn CD-R disks at 12x speed and CD-RW disks at 10x, while playback speed is 32x. The unit comes bundled with blank CD-R and CD-RW disks, a CD carry case and four software applications for recording, drag-anddrop file copying, creating digital photo albums and MP3 playback. to be recorded and click the Record button. Then, at the end of the track, you click the Stop button to stop the recording. Don’t worry if you accidentally record part of the follow­ ing track before hitting the Stop button. This unwanted material can easily be discarded later on. The same goes for any unwanted material at the start of the track and for any noise between the tracks. Once the recording has been made, it can be saved to a file on the hard disk. It can then be played back (just load the file and click the Play button) so that the sound quality can be checked. Alternatively, some programs record to a temporary file on the hard disk so that it can be checked before actually being saved. A worthwhile feature of the better programs is that they let you preview the waveform of the recorded audio – see Figs.5 & 11. The important thing here is that there be no flattening of the signal peaks, as this indicates clipping. If this occurs, the track should be discarded and re-recorded at a reduced level. By the way, be sure to save your files in the “wav” format if you intend to burn a conventional audio CD. Some programs also give you the ability to save your files in MP3 format, which is fine if you have an MP3 player. Alternatively, you can run the wav files through a dedicated MP3 ripper/encoder (eg, Music­Match or easy MP3). Cleaning up the sound As stated previously, if you’re getting clean sound straight off an LP, you won’t need to do much signal processing. However, one thing you’ll want to do is completely silence (or mute) the sound between tracks. In Cool Edit, you do that by zooming in on the track “lead-in” portion of the waveform, highlighting it with the mouse and then clicking Transform (on the Toolbar) and selecting Silence from the drop-down menu. The same is then done for the “lead-out” section at the end of the track. DC-Art32 uses a slightly different method. In this case, the highlighted segment is silenced by clicking Edit and select­ing Mute from the dropdown list. While you’re at, you might like to also shorten the lead-in and lead-out times by deleting certain sections. If there’s a lot of noise in the recording, then you’ll want to clean up the sound using various filters. There’s usually a strict procedure for going about this, however. Clicks and pops are usually dealt with first. In DC-Art32, you run the Impulse Noise Filter with the “Vinyl LP” option checked. This filter doesn’t just chop out the clicks, though. As it eliminates each click, it also fills in the “hole” by mathematically calculating what the waveform should be at that position and inserting this instead. In other words, it effectively interpolates the waveform across the brief gap that’s left by eliminating the click, to eliminate any audible effects. Equally effective “de-clickers” are included in other pack­ages, although sometimes these are available only as extra-cost plug-ins. Cool Edit 2000, for example, requires the Audio Clean­up Plug-In for click removal and this plug-in also does hiss remov­al. Sometimes, particularly nasty clicks and pops will require manual editing. Typically, you do that by zooming in on the waveform at the click location (confirmed by playing back that section of the waveform), then selecting the click and interpo­ lating the waveform across the selected area. Many programs also include a dynamic noise reduction filter and this is run after click filtering. The procedure usually involves sampling the noise from the track lead-in or lead-out grooves to build up a noise profile which is then subtracted from the rest of the recording. The idea here is to reduce the noise as much as possible while leaving the music intact. Fairly obviously, you have to perform this type of noise reduction before muting the beginning and end of the track. If you perform the muting first, there will be no noise left to sample and the dynamic noise reduction filter won’t work! On the other hand, dynamic noise reduction should be carried out after click removal, so that no large clicks are present in the noise profile. Problems like rumble can often be eliminated by running a high-pass filter, while notch filters can be employed against 50Hz and 100Hz hum in the recording. Similarly, a low-pass filter may prove effective in reducing DC Audio Restoration Tools – Making It Easy Fig.11: the trial version of DC-Art32 lets you record only the first 90 seconds of a track. This program is easy to drive and comes with lots of filters for cleaning up the sound. BEFORE Fig.12: the waveforms at right show the effect of running DC-Art32’s impulse filter on a track with lots of audible clicks. Note that the clicks are missing from the bottom two waveforms (on the yellow background). The remaining “spikes” are musical transients (they look like spikes due to the compressed horizontal scale of the waveforms). AFTER Fig.13: if you yearn for a valve sound, you’ll love this Virtual Valve Amplifier filter. You even get to choose between different types of valves and amplifier output configurations. January 2001  11 Burning the CD Fig.14: Adaptec’s Easy CD Creator really is easy – you just drag the tracks to be recorded into the workspace window. You can then drag the tracks around to rearrange their order and even play individual tracks back prior to burning. high-frequency noise. At each stage in the process, you should play back the filtered track to make sure you’re happy with the result before saving it to file. If the filter doesn’t have the desired effect, reset the parameters and run the filter again. Once you’ve cleaned up the noise, you might want to run a graphic equaliser or a preset filter to enhance the bass or treble, to liven up the sound. This can help revitalise the sound if an LP is worn, for example. Many programs also have filters for fade in and fade out and for adding compression and expan­sion. Another thing that you’ll probably want to do is run the “normalise” or “normalise gain” filter over each file. This filter searches for the highest peak in a file and adjusts the gain so that it just reaches the maximum recordable level. Just remember that the recording should be fairly close to this level in the first place, to get the best signal-to-noise ratio. It’s important to save your files to a separate folder, to make it easy to assemble the tracks when you run the burner software later on. Depending on the track length, you can expect files sizes in the 25-60Mb range and they should add up to no more than about 630Mb to allow sufficient overhead for the burner to write the contents. 12  Silicon Chip Fig.15: the “Disc-At-Once” option closes the recording session and prevents further data from being added to the disk later on. A session must be closed before the disk can be played back but you must leave the disk open if you plan on adding further sessions. It might take some work to get your tracks sounding just right but burning them to a CD requires little effort. Programs like Easy CD Creator are a no-brainer to use, no matter whether you’re creating audio or data CDs. The main thing to remember is that you are recording audio, not data, so select the audio CD layout option. You must also “close” the recording session if you want to play the CD back afterwards. You can either select this option before burning the disk or you can close the session afterwards. If you have a full complement of tracks, select the Disk-at-Once mode if this option is present. This mode burns and closes the disk in one operation. Alternatively, you can elect to close the session but leave the disk open so that you can to add tracks later on. Assuming that you have Easy CD Creator, you assemble the tracks to be recorded by dragging them from the file list to the workspace window. This done, the track order can be rearranged (just click and drag) and you can even play back individual tracks by right-clicking them and selecting “Play” from the drop-down list. This launches a bare-bones CD player with Play, Stop and Pause buttons (Fig.14). Finally, click the Record button to start the burn. Most programs give you the option of doing a test run first but if you’re the impatient type, you can bypass this step. Provided you have a reasonably fast hard disk, you should be able to burn at speeds of 4x or higher. Don’t interrupt the computer during this process, otherwise you’ll end up with a drink coaster. If that all sounds too hard, just run Easy CD Creator’s wizard. It really is a matter of following the proverbial bouncing ball – right up to burning the CD. SC Check Out These Online Sites Diamond Cut Productions (for DC-Art32 and Diamond Cut Millennium http://www.diamondcut.com Syntrillium Software (for Cool Edit 2000) - http://www.syntrilli­um.com DARTECH Inc (for DartPro) - http://www.dartpro.com Sonic Foundry (for Sound Forge XP 4.5) www.sonicfoundry.com Multimedia’n’Music - http://www.multimedia-music.com.au (for retail copies of Diamond Cut and Dart Pro software (all version). They also have an excellent tutorial site at http://www.enhance­daudio.com.au