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LPs TO CDs Want to transfer your old LPs or 78 records to CD or MP3 format? Here’s how to go about it and get rid of surface noise in the process. By JOHN CLARKE C OMPUTER TECHNOLOGY now makes it easy to restore your old vinyl records and convert them to CDs or MP3 files. You don’t require an expensive sound studio to do it, just your PC and suitable software. In fact, many owners of personal computers don’t realise that they already have powerful audio editing tools just waiting to be tried. Correctly used, these tools will let you listen to your favourite recordings once again without the usual background clicks and pops and surface noise. Of course, to play back your old LPs (or 78s), you’ll need a suitable turntable. You’ll also need a stereo amplifier with RIAA preamplifier stages, to process the output from the turntable’s magnetic pick-up cartridge such as the one described in the August 2006 issue. Making it better Often, you don’t have to buy add-on packages in order to process the audio from your LPs. Instead, the software is usually bundled with your PC’s CD or DVD burner. These software packages commonly include such enhancements as de-clicking and noise reduction. In fact, the quality of the sound after processing a recording using such software can be quite a revelation. The unwanted noise is effectively filtered out, leaving you with crystal-clear sound. To appreciate just how well you can clean up a recording, take a look at the audio signal screen grabs shown in Figs.2 & 3. First, a small section from an audio track on an LP record was recorded using the Nero Wave Editor. Fig.2 shows this audio track section after it has passed unprocessed through our Magnetic Cartridge Preamplifier (both left and right channels shown). Notice the small sharp spikes in the waveforms of Fig.2. These are the clicks and pops that you normally hear when playing a record. Now take a look at the second screen grab (Fig.3). In this case, the signal Fig.1: here’s how to connect your turntable to the PC’s soundcard via a phono preamplifier such as the unit described last month. You can monitor the sound via your PC’s speakers or via an external amplifier and speakers as shown here. 34  Silicon Chip siliconchip.com.au Fig.2 (left): this screen grab shows a small section of a recorded audio track from an LP record prior to processing. The small sharp spikes (circled) are the clicks and pops which are picked up due to imperfections in the record’s surface. Fig.3 (below): this is the signal after processing in the Nero Wave Editor to remove surface noise and clicks and pops. The spikes are now gone. has been processed in the Nero Wave Editor to remove surface noise and the clicks and pops. As a result, the spikes have now disappeared and the sound quality is greatly enhanced. The RIAA preamplifier Because vinyl recordings have well and truly had their day, most modern amplifiers (and preamplifiers) lack suitable inputs for a turntable. So even if you want to play a vinyl record using your old turntable, you can’t. So you will need a suitable preamplifier? Let’s look at this in more detail. In order to play vinyl records from 1953 onwards, your sound system must have an RIAA preamplifier. This gives a standard equalisation specified by the Recording Industries Association of America – see Fig.5. RIAA equalisation compensates for the way the audio signals are recorded via the spiral groove on the vinyl surface – ie, with the treble boosted and the bass curtailed. During playback, the reverse happens, with the bass frequencies suitably boosted and the treble cut. During the recording process, the bass frequencies need to be reduced in level to prevent over-modulating the groove and breaking into the adjacent track. In addition, the fact that a magnetic cartridge is used for playback means that the levels will automatically be greater for the higher frequencies compared to the lower siliconchip.com.au frequencies. Hence, RIAA equalisation was adopted as the standard many years ago. that you can select the correct curve for your application. 78 RPM records Your turntable should be equipped with a magnetic pick-up cartridge and have 45 RPM and 33 RPM speed settings. To play 78 RPM recordings, you will need a cartridge that accepts the correct stylus (more on this later) and your turntable will need a 78 RPM speed setting as well. Note that some recording software packages include RIAA and other equalisation curves. However, don’t try connecting the cartridge output directly to the computer and then relying on the software for the RIAA equalisation – the 10mV (typical) signal level from a cartridge is far too low to produce good results. You must use a Unfortunately, the RIAA standard is unsuitable for playing 78 RPM records and pre-1955 LPs. These older records were recorded without adopting any particular response standard and most record companies had their own method of tailoring the response. To make matters worse, a rotational speed of 78 RPM is not necessarily the correct value for all 78s. Instead, the user may have to adjust the speed to somewhere between 72 RPM and 85 RPM in order to obtain the correct pitch. Our new preamplifier in last month’s issue has been designed so The turntable September 2006  35 Fig.4: this is the setup to use if you have a stereo amplifier with an inbuilt phono preamp stage. The sound card goes in the tape loop of the amplifier. preamplifier to boost the signal and provide the required equalisation. By the way, if you are using an amplifier with an inbuilt RIAA preamplifier, the signal for the computer can be derived from the Tape Out sockets. In any case, make sure that the line input volume level is turned up. This is done in Windows XP by accessing Start/Control Panel/Sounds and Audio Devices/Audio and under sound recording select Volume – see Fig.6. Basic checks Before playing a record, check that the stylus is in good condition and is dust-free. Check also that the tracking weight and the anti-skating adjustment are correct. The record surface should be cleaned with an anti-static cloth to ensure it is lint free. Having done that, try playing a standard LP record and monitor it via your PC’s loudspeakers. Note that some computers and some CRT monitors may interfere with the audio signal. If that happens, try moving the turntable and preamplifier further away from the computer. If you encounter lots of mains hum, try earthing the turntable. Some turntables have an earth wire that must be connected to an earth – either a signal earth or a mains earth. In the first instance, try connecting the earth lead from the turntable to the earth binding post on the SILICON CHIP preamplifier. If this doesn’t cure the hum, then the turntable may need a mains earth. If you are using a computer that has Fig.5: the RIAA equalisation curve. During playback, the bass frequencies are boosted and the treble cut to compensate for the recording characteristics. 36  Silicon Chip an earthed metal case, try connecting it to the banana socket on the preamplifier. If you have a laptop computer, try using an earthed plugpack such as the Jaycar MP-3022 with a 5-pin DIN line plug connected to its output lead. Wire the earth lead to the centre pin of the DIN plug and each low-voltage AC lead to the outer two pins as shown in Fig.4 in last month’s preamplifier article. Of course, you will also have to install the 5-pin DIN socket on the preamp’s PC board. Recording The recording can be made using either a PC or an MP3 player that has a line input socket. The advantage of using a computer is that the signal can be cleaned up to remove the noise from the signal. To record to a computer, you will need suitable recording software plus a CD burner if you wish to later burn the recording to a CD. If your computer has Nero installed, then you can use Nero Wave Editor (Start\All Programs\Nero Burning ROM\Nero Wave Editor) to record. If you don’t have any recording software, you can download a package from the internet. For example, NCH’s Swift Sound Wave Pad (www.nch.com.au/wavepad/) provides a trial version of their WavePad Masters Edition software package. It includes noise reduction, click and pop removal and CD burning software all in one package (note: we found that the automatic click and pop removal in WavePad 3.02 was not successful although it may be improved in later versions. Manual click removal worked well, however). Alternatively you can try the DC Art Millennium restoration software (available as a trial for 10 days) from http:// siliconchip.com.au Fig.6: be sure to turn up the volume for the line input. Fig.9: use Nero’s Enhancement\Declicker feature to remove noise and any clicks and pops from the recorded signal. Fig.7: when recording, select the standard 44.1kHz sample rate and 16-bit depth. Fig.8: set the recording level for good signal strength without clipping. www.enhancedaudio.com/record_ restoration.htm. The software packages are relatively easy to use and they all use menus and icons that are similar in operation. Note that you may want to use more than one package to obtain all the features you want. For more information, take a look at the LP Restoration article in the January 2001 issue of SILICON CHIP. The software descriptions and comments are still relevant today, although the screen shots show older versions of the software. Using Nero Wave Edit standard 44.1kHz sample rate with 16-bit depth (Fig.7). Next, set the recording level so that it doesn’t clip. It’s simply a matter of setting the level control on the preamplifier so that level indicators show sufficient signal level – see Fig.8. Once a track has been recorded, you can remove the noise and any clicks and pops using the Enhancement\ Declicker feature – Fig.9. To do this, select the file by first right-clicking your mouse at the start of the recording and dragging the cursor (or click the “select all” icon), then select the Declicker and Noise Reduction features which are located under Enhancement. If necessary, you can alter the parameters for the declicker and decrackle features using the dialog shown in Fig.10. These include the threshold level and maximum length. The default settings generally work fine but you may need to experiment when a record has severe clicks and pops. We found that the DC Art Millennium restoration software also works well when it comes to removing clicks and pops from records. In this case, the “Impulse” filter removes clicks, while the “Median” filter removes crackles. The authors also recommend reversing the file (select Effects\Reverse File) and re-running the Impulse filter for best click removal results. The file then needs to be reversed again, to restore the original direction. Fig.11 shows the original “wav” file (grey background waveforms) after a recording from an LP record. The lower waveforms on the yellow background show the effect of passing the recording through the Impulse filter. As shown, the clicks have been removed. If necessary, stubborn clicks can be manually removed if they are still there after using the automatic mode. Another sound editing software package called Audacity is available Fig.10: the default declicker and decrackle settings generally work fine in Nero but you can also set them manually if the record has severe clicks and pops. To begin a recording select Audio\ Record, then select the recording quality. For a normal recording, choose the siliconchip.com.au September 2006  37 Fig.11: the DC Art Millennium restoration software also works well when it comes to removing clicks and pops from records. Fig.12: select 44.1kHz and 16bit when saving files in wav format. free from http://audacity.sourceforge. net/. It also includes click removal and filter tools, making it suitable for restoring damaged recordings. Following click removal, you can do further processing such as noise removal, hiss removal and equalisation (for equalisation, see the section concerning 78 recordings). Noise reduction is made by referencing the noise level to a “silent” part of the recording and then running the noise reduction feature. Once you are happy with the results, the file can be saved in the standard CD wav format of 44.1kHz and 16-bit (Fig.12). Alternatively, files can be saved in the MP3 format. Bit rates There are several bit rates to choose from when making an MP3 file. These range from 320kb/s with a 4:1 compression) down to 96kb/s. For music, select at least 192kb/s or preferably 256kb/s Fig.13: you can burn files to CD using Nero Express or similar burning software. Alternatively, a good freeware program is CDBurnerXP Pro. 38  Silicon Chip (6:1 compression), or 320kb/s for the highest quality. Of course, the higher the bit rate, the bigger the file and the lower the number of tracks that can be stored on an MP3 player. Other formats include AAC (or MP4) format and this produces a further improvement over MP3 encoding. As before, select the higher bit rates for best sound quality. Some MP3 players such as the Apple iPODs will also accept the MP4 format. Incidentally, a .wav file has a 16-bit x 44.1kHz x 2 (for stereo) sampling rate. This corresponds to a 1411.2kb/s rate and gives some idea why .wav files are superior to MP3s. When you have restored all the tracks on the LP and saved them into separate files, you can burn them to a CD using Nero Express (Fig.13) or similar burning software. If you don’t have Nero, then there should be some kind of CD burning software supplied with your CD drive. You can also use the Windows media player or a freeware program such as CDBurnerXP Pro. If you are settling for the MP3 format, the files can be transferred to your MP3 player or Apple iPOD. You could also burn them onto a CD as an MP3 disc (this disc format can also be processed with Nero Express). In this way, you can store more music on a single CD than you can with standard .wav files. However, you need a player that can play MP3 files (not all can) and the sound quality won’t be as good. Older recordings & 78s As mentioned earlier in this article, the RIAA response curve is not suitable for older (pre-1955) recordings. However, if the you build the preamplifier described last month, you can choose the equalisation required to suit your LPs and 78s. For microgroove LPs (33 RPM) and 45 RPM records, choose “ffrr LP” for pre-1955 English Decca LPs; “EMI LP” for pre-1955 HMV and English Columbia LPs; “Columbia” for older American Columbia LPs; and “NARTB” for some early American labels. If you are unsure of the equalisation required, select the RIAA curve. You can then later equalise the sound using a software equaliser. Adjust the response until you are happy with the results (Fig.14). Note that it’s best to use a preamplifier that has the correct response for the recording already built in, rather siliconchip.com.au than rely solely on software. This will provide the best signal-to-noise ratio and the lowest distortion. Any equalisation that you subsequently apply later on then only has to make relatively minor changes that do not involve large signal level shifts. To play 78s, you will require a 3-mil (.003-inch) stylus (the Stanton 500 cartridge can be supplied with a 3-mil stylus) and a preferably a turntable that will run at 78 RPM. Note that some DJ turntables have an add-speed function, whereby pressing both the 33 RPM and 45 RPM selections sets the speed at 78 RPM. A turntable with pitch control is even better. Alternatively, provided you are using the correct stylus, you can play the record at 45 RPM and change the playback speed after recording in the software. However, this manner of recording will also affect the equalisation because all the frequencies from the record will be lower. This will have to be corrected by adjusting the software equalisation. When playing 78s at 78 RPM, use these equalisation curves: “WESTREX” (English Western Electric) for HMV 78s that have a triangle matrix code and English Columbia 78s with a matrix code; “BLUMLEIN” for HMV records with a square adjacent to the matrix number, for English Columbia 78s with a (c) symbol and for HMVs that have no code and are dated from 1945 up to about 1953; and “BSI 78” for all post 1953 78s. If playing a 78 record at 45 RPM, select an equalisation curve that has a lower bass and treble turnover frequency than the one that should be used. For example, if the ffrr 78 curve applies at 78 RPM, select the Decca 78 curve for 45 RPM instead. This curve has a lower turnover frequency for both bass and treble and would match the lower frequencies experienced when playing at the slower speed. If you are unsure of the equalisation that needs to be used, try recording using two different equalisations (eg, the Decca 78 and Westrex equalisations), then choose the one that sounds the best. Final tweaking can then be done using a software equaliser (Fig.15). Note that some 78s will sound off pitch. In this case, you can adjust the pitch using the recording software (Fig.16). Similarly, if the recording was made at 45 RPM, adjust the playback SC speed to 173% (Fig.17). siliconchip.com.au Fig.14 & 15: software equalisers can be used to adjust the equalisation and to enhance the sound if necessary. Fig.16: recordings that sound off-pitch can be corrected using Nero’s “Pitch Change” adjustment. Fig.17: the “Speed Change” feature is useful for correcting 78s that were recorded at 45 RPM (ie, use 173%). What About Copyright? Transferring copyright music and other copyright material from one format to another is currently illegal in Australia. In other words, it is illegal to transfer the recording of an LP to a CD or from a CD to an MP3 player. To obtain permission to do this, you must contact the recording company that holds the copyright for each recording you wish to transfer. This copying restriction does not apply if the copyright has expired. It is expected that this law is about to change in Australia to allow copying of already purchased copyrighted material to other media for your own personal use under certain circumstances. September 2006  39