Transferring LPs to CDR: Some Advice

Page last updated: 18th March 2006

Before we start, the #1 question people email me is:
"I can play through the computer speakers, but can't record to hard disk"
(or: "When I record to hard disk, the resulting file contains silence")
HERE IS THE ANSWER

I will be away from 9th to 24th October 2014, so will be unable to reply to any emails during that period. I apologise for any inconvenience this causes.


The Demise of CoolEdit 2000

Many people will have heard of a general purpose shareware audio editor called CoolEdit 2000 (made by Syntrillium Software). I have recommended this program in the past as an excellent example of its kind. There are a number of references to it on this page. In 2004, Adobe Systems acquired the rights to the range of software produced by Syntrillium. Unfortunately, they have decided to discontinue CoolEdit 2000, leaving only the far more expensive multi-track CoolEdit Pro (now renamed Adobe Audition) available. This is a sad day for people who have need of a stereo-only audio editor. At its price ($299) I cannot seriously suggest that Adobe Audition is a cost-effective program for use on transfers of stereo LP records. So a suitable affordable alternative to CoolEdit 2000 is needed.

I have looked at a few other inexpensive audio editors, including Audacity, Pro Tools Free and Sound Forge Studio (which itself has recently been acquired by Sony), but none of them feel as good to me as CoolEdit 2000. Of course, as a long-time user of CoolEdit 2000 (which I shall continue to use as my preferred audio editor), it is inevitable that I will have some sort of in-built bias towards programs that look and feel similar. I must emphasise that these three editors are all very fine programs, and considering the varied reactions people have to to programs of this type, I would certainly encourage you to evaluate them for yourself.

Since it is freeware and has many enthusiastic supporters, I felt it only fair to give Audacity a more careful evaluation, and am coming round to the conclusion that my initial reaction to it was unfairly negative due to my history with CoolEdit 2000. It is now clear to me that Audacity is a fine audio editor with many ecellent features, and so I recommend it alongside GoldWave, which has been a recommendation for many years.

Getting a Copy of CoolEdit 2000

Finding a copy of CoolEdit 2000 is difficult. It is rare to see it on eBay (although there are usually copies of CoolEdit Pro available). Some links I had given on earlier versions of this page no longer work. Because of this, I have decided to host the installation files for CoolEdit 2000. I believe this is probably legal, because these are the files that Syntrillium used to make available for download in order to evaluate the program. I must stress that the files I am hosting only provide you with evaluation versions of the program: if you want to get them unlocked, then you'll have to acquire suitable registration codes from elsewhere. Please do not email me with a request for registration codes - to supply them would be illegal and I will NOT do so. Note that if Adobe come after me, I will remove these files from this site.

Here are the three installation programs:

Brief installation instructions:

Someone else found a site where various old versions of CoolEdit and CoolEdit Pro can be found: http://www.oldversion.com/program.php?n=coolpro.


Preliminaries

This page of notes is a distillation of my experiences in transferring LPs to CDR. I offer it as hopefully unbiased advice to others wishing to do the same thing. I have attempted to address the whole process at a reasonably deep level. Some parts of it are bound to be of no interest to some readers; I hope the sections are obvious enough that you can skip those parts which don't apply to you.

My standards are high. I have a stereo system which all but a small minority of audiophile extremists would regard as "very high end". I'm not interested in putting anything onto a CDR unless I can get fairly close to perfection. The advice contained in these notes is empirical, and results from my own personal experiences.

I am not a digital audio professional. Transferring LPs to CDR is my hobby, born of the desire to preserve those parts of my LP collection which (i) are unavailable on CD, or (ii) aren't essential enough to me to be worth spending the money replacing them on CD.

I work on a PC, and can only offer advice in that arena. I have no knowledge whatsoever of doing this kind of work on Macs or Unix machines.

I get quite a few email enquiries from people who have found this page, and some questions tend to be asked repeatedly. They aren't directly relevant to the task of transferring LP to CDR, but are more general about audio on a PC. Therefore I've put together a separate page (Clive's FAQ) to answer these. Before emailing me with a question about audio on a PC, please check this page to see if it's answered there.

Obviously I can't write down everything I've ever discovered about this process, so if you have any other specific questions, feel free to email me. But before you do, I would ask you to check the FAQ carefully to see if your question is already answered there. Please also note that changes in my circumstances mean that I will not be able to respond to emails as quickly as I have done in the past, but I will try to continue to help wherever I can.

While on the subject of emails, a request. I have been receiving a great deal of spam recently, so I have now activated Spam Assassin at my email host, and any email that looks like spam will be automatically deleted without ever being delivered to me. To ensure that any email you need to send to me gets through, make sure it has an unambiguous subject line and is in plain text format. Recently, a lot of spam has used the trick of providing no subject line at all. Where such spam gets through to me, having avoided detection by Spam Assassin, I have up to now checked it. Since such subjectless emails have been virtually 100% spam, I have now decided to delete all subjectless emails unread. So, if you send me email without any subject, it will not be read or replied to.

And finally, a disclaimer about Adaptec/Roxio software. I sometimes receive emails asking for help regarding the Adaptec/Roxio products Easy CD Creator and Spin Doctor. As far as I can make out, it is possible to get to this page via links that start on Roxio's website, and so some people arrive here under the mistaken impression that I am in some way connected to Adaptec/Roxio. Let me make my position clear. I have absolutely no connection to Adaptec/Roxio. I have evaluated both Easy CD Creator and Spin Doctor in the past, but do not use either of them and am unable to offer specific advice about them.


At the end of this document is a list of useful links. I will just point out that I cannot comment on the accuracy of the translations into other languages that have been made by various people.

Slightly off-topic: why use a computer?: I got some email from someone who asked me to add a short paragraph discussing alternative methods of archiving LPs without using a computer, so I have done so at the end of these notes.


Overview

The task of transferring an LP to CDR comprises 3 basic steps:
  1. Recording the LP to hard disk.
  2. Cleaning up the vinyl damage using a computer based WAV file editor.
  3. Burning the CDR

Recording the LP to Hard Disk

Clean the LP

Before you start, you should do your best to clean the record as thoroughly as possible; getting dust and gunge out of the grooves will eliminate a fair amount of the lower level noise that would otherwise require a very time-consuming job to remove at a later stage. Ideally use a vacuum device; even better get them professionally cleaned by someone who has access to a Keith Monks cleaning machine.

If you don't have access to a vacuum machine, and the record is very dirty, then I've recently tried out a fluid from Australia known as The Vinyl Solution which is inexpensive and works well on very dirty records. I have to say that I do not know what is in this fluid, and so cannot take responsibility for any long-term effects it may have on the vinyl. I suspect, but cannot say with any certainty, that it may have the same alleged drawbacks as wet playing, but if all you want is to make one good transfer of an LP and can't afford to invest in a vacuum cleaner, it seems like a good approach.

Playing the LP

Use a good quality turntable to play the LP. The pickup cartridge should be properly aligned and the stylus should be in good condition and clean.

A turntable is a mechanical device which is vulnerable to airborne and floorborne vibrations. Such vibrations can degrade the playback quality quite noticably. Even the very best turntables can suffer in this respect. Therefore, while recording the LP, keep surrounding sound levels as low as possible. Ideally you should not use any kind of monitoring at all; don't worry about knowing when the music starts and ends, just start recording from before placing the stylus on the lead-in groove and continue recording right into the run-out groove (trimming off these extra bits later is easy).

The Need for a Preamp
I will assume that you will use a moving magnet or moving coil cartridge (all high quality cartridges are one of these two types). The signal from such a cartridge is both low in level (typically <5mV for moving magnet, <0.5mV for moving coil) so must be boosted to about 100mV needed to drive line level inputs, and is also RIAA equalised (applied when the LP is mastered to get around mechanical limitations of the LP system) which must be reversed so as to provide a flat frequency response for the line input. Both of these necessary operations are achieved with a suitable preamp. If you have a receiver or stereo amplifier with a "phono" input, that input will perform this task, and the resulting line level output will be available on the receiver/amplifier tape output. Tom Weber informs me that Radio Shack sells an inexpensive amplifier (model number SA-155) for about $65 which is suitable, and I pass on his recommendation here while emphasising that I have no personal experience of this device. I believe that Radio Shack also sell a standalone phono preamp for about $30. Reports from various sources lead me to believe that the quality of this preamp is no more than "servicable". NAD make a well-respected preamp, the PP-1, for about $60. Some readers have reported that the inexpensive phono preamps available at www.phonopreamps.com work well, so I pass on this information while stressing that I have not had any personal experience with them. It is also quite possible to build your own if you're at all adept at DIY electronics; There are a couple of suitable circuit diagrams on Mike Richter's site, and PAiA Electronics sell a DIY kit. If you have higher quality equipment such as a separate preamp and poweramp, you'll know what I'm talking about and I leave the choice of a quality phono stage up to you.

I see that a few companies, including Stanton and Denon, make turntables that have built-in phono preamps, and a few even have SPDIF digital outputs. That said, these are DJ type turntables, which tend to be built for ruggedness and reliability rather than outright sound quality.

How about "wet playing"?
One option you might like to consider is "wet playing". The idea here is to flood the LP with a suitable liquid while it is being played, in the hope that dirt which normally sits in the grooves (and will therefore be tracked by the stylus) will be lifted into suspension and therefore will not influence the stylus.

Other people have different views as to why wet playing works. There is a school of thought that it's not really anything to do with lifting dirt into suspension, but rather that it alters the damping of the stylus and/or allows the stylus to aquaplane over minor imperfections.

I should also report that some people state that wet playing actually damages the groove wall. The argument is as follows. When you play an LP, the (hard) diamond stylus deforms the (soft) vinyl groove. When played normally (ie. dry), the friction causes the vinyl to heat up, which allows it to deform and return to its original shape after a while. If, however, the LP is played wet, the fluid acts as a coolant which prevents the deformation, allowing the stylus instead to carve slivers of vinyl off the groove walls.

Others have reported that wet playing can cause a kind of sludge (ie. the dirt from the LP suspended in the liquid) to accumulate on the stylus. This would then dry and harden, be very difficult to clean off, and cause subsequent mistracking. I've not noticed this myself, but would guess that the scale of this problem would be affected by how dirty the LP is, the exact composition of the liquid used, and how highly polished the stylus is.

I have experimented with wet playing, and it does indeed reduce some (but by no means all) forms of surface noise. There are a number of issues, though:

I must point out that I have no authoritative knowledge about wet playing, but feel that if I discuss it at all, it is important to mention all the opinions of which I am aware.

Recording to Hard Disk

Once you have a line level signal, it needs to be digitised and recorded onto the computer's hard disk. Note that for a typical 40 minute LP, you'll need about 500Mb of disk space, and depending on what PC editor(s) you use, you might need another 500Mb for temporary files. Count on needing about a gigabyte in total.

The standard Sound Recorder utility that comes with Windows is not suitable for this task because it records to main RAM and only writes the results to hard disk when recording finishes. This means that recording time is limited by the amount of RAM in the PC; since 16 bit stereo at 44kHz uses about 10MB per minute, there's no way you'll be able to record an entire LP side using Sound Recorder. What is needed is a utility that can record direct to the hard disk. There are a large number of such utilities available as shareware. My own shareware Wave Repair supports hard disk recording, has rather better record level metering than most other packages, and if used as a simple record utility it is freeware. Of the other packages around, the cheapest two I am aware of are CD Wave and RIP Vinyl. LP Ripper is another fairly well-known recording program that you may wish to investigate. Another fairly straightforward and inexpensive recording package is PolderbitS. Although I've not had a chance to evaluate it properly, a number of users are very impressed by it, so for that reason it is worth a mention. GoldWave (a very good general purpose audio editor) also offers direct to hard disk recording.

Discussion of Soundcard Types
Once you have a package capable of recording direct to hard disk, there are three basic approaches to digitising the line level signal:
Normal Soundcards
Using a "normal" soundcard is certainly the cheapest option on a desktop PC. The inside of a PC is a very hostile environment for analogue signals, and some years ago many soundcards were susceptible to interference, resulting in high noise levels and/or "chirrups and whistles". This is no longer a common problem, and the vast majority of modern PCI bus soundcards have pretty good noise performance. It is easy to buy an inexpensive soundcard whose noise floor is well below that of vinyl LPs.

My experience is that currently available soundcards generally fall into five categories:

  1. Cheap cards with unknown brand names. It is of course possible that some of these may be fine, but in general they have fairly dreadful sound quality. Avoid.
  2. Soundcards built onto motherboards. These days they are usually some cheap AC97 chipset, and they come in varying qualities (probably more to do with the motherboard layout than the chipset itself). You might get lucky and find one that gives reasonable quality, but as a general rule they are to be avoided.
  3. Mainstream cards like the PCI-bus Soundblasters and their like. These can give reasonable sound quality, but they tend not to be completely transparent. At the top end of this class of card are devices like the M-Audio Revolution series, which are very good indeed; more than good enough to record LPs.
  4. Semi-pro cards in the sub-$200 price range, such as those from M-Audio, Echo, Terratec, etc. These are typically very good, and more than adequate to capture anything from a vinyl LP. They typically have RCA or XLR sockets rather than the stereo minijacks found on mainstream cards, which can give more reliable connections.
  5. Very high end cards such as the DAL CardDeluxe and LynxTwo. These are serious professional cards and can be considered overkill.
The following tip comes courtesy of Richard Melton: When using an analogue soundcard, it is often a good idea to mute all inputs and outputs that aren't actually being used (eg. mic, MIDI, etc). This will improve the noise performance of many soundcards.

www.pcavtech.com/soundcards/index.htm has a lot of good information about analogue soundcards.

USB Audio Devices
These are usually more expensive than normal PCI bus soundcards, and as a general rule they are not such high quality. However, I must emphasise that I have not used this type of input device, so can only pass on information I have gleaned from other sources. The general opinion out there seems to be that if you are able to use a "proper" PCI card, then do so. Only resort to USB if you need portability or are using a laptop. Since I have never used one of these devices, I cannot offer any recommendations, so the following is simply a list of manufacturers I have found who offer such products: Creative, M-Audio, Edirol, Tascam, Terratec, Philips. This list is not complete; there are bound to be a number of other suppliers that I have not come across.

Digital I/O Cards
As for soundcards which can receive a digital signal, there are a host of options:
  1. The cheapest I know of that's widely available is the Midiman DiO2448.
  2. There is another card called the Zoltrix Nightingale which uses the same chipset as the DiO2448 which supports SPDIF I/O and has a price under $40. However there are two drawbacks: (i) it's very hard to actually find one; (ii) it only has optical (Toslink) input, although there is a simple DIY modification to add COAX input.
  3. Some inexpensive mainstream cards can have SPDIF input capability. However, many of these resample the SPDIF input to an onboard clock rate, so they do not allow for bit-perfect transfer of external digital audio to the hard disk.
  4. Most of the higher-end analogue soundcards (from the M-Audio Audiophile upwards) also have bit-perfect digital I/O capabilities.
  5. And finally, you may hear stories about $20 soundcards with SPDIF I/O. Various people have tested these cards and in the vast majority of cases could not make the SPDIF I/O work properly. Even those few people who did have success needed to build extra bits of circuitry.

As for the outboard A/D converters themselves, I don't really have a lot of experience in this area, but can report that some low cost converters which have good reputations are the Midiman Flying Calf (about $200), the Lucid ADA1000 (about $500), the Symetrix 620 (an old design at about $600, still highly regarded and something of a de-facto standard in semi-pro studios), and the Lucid AD9624 (about $800). Above this we start to get into serious professional territory, and I'm not qualified to offer advice at that level.

For the record, I personally use an M-Audio Audiophile 2496, which can be had for under $200 and which has excellent analogue I/O (certainly good enough to faithfully record anything from a domestic analogue source) as well as bit-perfect SPDIF I/O.

An Alternative Approach that By-Passes the Soundcard
In the last year or so, consumer grade audio CD-RW recorders have come on to the market. These devices can be hooked up to your stereo system like a tape deck. This presents a new approach you might like to consider: record the LP to a CD-RW disc using an audio CD recorder, then transfer that to hard disk using digital audio extraction with your CDROM drive. The CD-RW disc can then be reused for the next transfer. This has the following advantages:
Is 16 bit Recording Enough?
Audio forums and newsgroups often have discussions about whether there is a need to record vinyl LPs at greater than 16 bit resolution. There is little point in taking the word of some "golden eared audiophile" on an ego trip who states that he or she has heard the degradation inflicted by 16 bit recording: solid measurements are needed. I will attempt here to examine some of the scientific evidence that may help you make a decision for yourself.

Let's start with the statement made by those who proclaim that 16 bits are enough. They will say that the noise floor of a vinyl LP is about -60dB on a good day. Perhaps a really good quality LP pressed with loving care on heavy duty pure vinyl might manage about -70dB. This is still 26dB higher than the noise floor of 16 bit digital. Therefore, they conclude, 16 bits is more than sufficient.

The common counter to this argument is that the noise on a vinyl LP varies with frequency. The bulk of vinyl surface noise is at low frequencies: at higher frequencies, the noise floor is in fact very low. These claims are usually backed up with graphs showing a frequency analysis of a silent groove on an LP. A typical example of this argument can be found on the Audioholics website. The graphs presented show that at frequencies above about 500Hz, the noise floor of an LP can approach, or even beat, -96dB.

Just in case the Audioholics website is unavailable, and also to verify their findings, here is a frequency analysis of the silent groove from a high quality test LP (HiFi Sound HFS75):

This verifies a noise level below -80dB from about 100Hz upwards, improving to better than -96dB above about 2kHz. Measuring the RMS level of this recording gives a value of -51dB. After applying a brick wall filter at 100Hz to remove those frequencies giving the greatest contribution to the noise, the RMS level drops to -70dB. But this is still at least 20dB higher than the graph indicates for higher frequencies.

Case proven for the need to record LPs at greater than 16 bits, it would seem. But this does not match my experience. I have always felt that 16 bit recording is more than adequate for vinyl LPs. This is based on the simple observation that such recordings sound identical to the original LP within the context of my own reasonably high quality system (Moth record cleaning machine, Linn Sondek LP12/Lingo/Ittok/Karma turntable, Naim 42.5K phono preamp, M-Audio Audiophile 2496 soundcard, ATC SCM100A active speakers). When I first read some of these articles showing the low noise floor at high frequencies, I was both shocked and intrigued, and decided to investigate further. And I discovered that these frequency spectrum analysis graphs can be misleading. Consider this one:

It clearly shows a noise level at around -120dB all the way from about 10Hz upwards (and better than -100dB from DC to 10Hz). You might be surprised to learn that this graph is the analysis of a 16 bit recording of nothing. In other words, the noise floor of an idling 16 bit digital signal, randomly fluctuating between sample values of 0 and 1 (with the occasional 2 popping up now and then). If we apply the same reasoning that is given to the silent LP groove graph, we would conclude that the noise floor of 16 bit digital audio is -120dB. But we all know that it is really -96dB, and indeed the RMS level of this recording is reported as -96dB.

My conclusion from these tests is that a casual inspection of frequency analysis graphs fools you into believing the noise level is at least 20dB lower than it actually is. So the apparent -96dB noise floor of a high quality vinyl record at high frequencies is in reality more like -76dB at best. Or looking at things another way, if you want to show the noise floor of a vinyl LP using frequency analysis graphs, then it's only fair to use the same method to measure the noise floor of 16 bit digital audio, in which case we see that it is still more than 20dB below the LP. I feel it is now possible to answer the question posed at the top of this section:

Humming Along with the Music

It's quite possible that when you hook up the line level output from the LP playback system to the input of your PC's soundcard, a hum will result. This is usually due to problems with the ground connections on various parts of the whole setup (usually the PC's ground and the stereo system's ground are at different voltages).

Before assuming that it is a ground problem, however, just be sure to check that you have no signal cables trailing alongside mains cables, as this can cause hum pickup. If you have any cables like this, try separating the mains and signal cables by several inches. This may solve the hum problem, but if it doesn't, then you'll have to think about the grounding arrangements. Unfortunately, trying to rectify this kind of hum can be problematic, but there are a few things you can try. But before we begin, a warning: if you are at all unsure what you are doing, then do not remove any ground connections on the mains supply to components. (Electrocution is generally regarded as more serious than a bit of hum).

Setting Record Levels

Whether you choose to go with a "normal" soundcard or external A/D convertor, it is important to set the input levels accordingly. The aim here is to get peaks as close to 0dB as possible without exceeding that level. This is for two reasons: As a guide, I tend to pick what I think is the loudest part of the LP (if you know the music well, you'll know where the loud bits are; if it's an unfamiliar record, visually inspect the grooves for the ones that wiggle the most), and set record levels to register about -3dB for that part, which leaves a little headroom in reserve.

Unlike recording to analogue tape (where pushing the signal level well past the nominal maximum level can sometimes be a valid approach) it is absolutely crucial that you never exceed the 0dB level. If you do, the result is digital clipping; an extremely unpleasant-sounding type of distortion.

Track Splitting

When recording an LP to hard disk, don't be tempted to try and split the tracks at this stage. You will want to retain the correct timing of inter-track gaps on the final CD, and it is much easier to split the tracks and retain the correct length gap using a PC editor later. (Indeed, you may use a CDR burning package that doesn't need the tracks to be in separate files anyway).


Cleaning up the Recording

Once the signal is on hard disk, the hard work begins. Before we start, let me state from the outset that many people hope to find a single software package that will do everything they need. This is an unrealistic expectation; in general you will need a toolkit of various packages. In the notes which follow I will point out the strengths of those which I have personally used, and in passing will mention other packages which I have not used but nevertheless have a good reputation.

Mono LPs

Most people will be recording from stereo records. However, if you want to transfer a mono LP there are a few extra issues to consider which I'd like to deal with first. A CD cannot be mono; you must record it in stereo. The ideal situation is that the two channels are identical, but if you just play a mono LP on a standard stereo turntable, the chances of getting identical left and right channels is virtually nil. It may well be that they are close enough that the results sound fine and you don't feel the need to change anything.

However, what if the two channels are sufficiently different that the results are not really acceptable mono? To arrive at two identical channels, there are basically three options:

Either of the first two options can be achieved with creative wiring of the turntable's cartridge, but a weighted merge is only really possible using a mixer. You can of course deal with it all in software once the signal is on hard disk, and this is the course I'd recommend. One advantage to recording the two channels to hard disk as stereo is that if there is a click on one channel only, you can copy over a clean section from the other channel. Only after this stage would it then be appropriate to start mixing the channels to mono.

Reducing Constant Noise

The amount of constant background noise (eg. hiss) is quite low on vinyl LPs. (I do not include "crackle" in this category: vinyl crackle isn't really a constant noise, and it is usually better removed using the methods described in the next section). Constant noise is usually only significant on historic records, so unless you find it particularly objectionable it is probably best to leave it alone. That said, it is rather easier to deal with than random noise such as clicks, pops and crackle.

Many audio editors include a broadband noise reduction feature. They usually operate by first taking a "noise fingerprint" from a region that contains only noise, then removing that noise fingerprint from the music using a process known as "Spectral Subtraction". This process can work well, but for tape hiss can cut out quite a bit of the high frequency programme content. It should also be used in moderation, since it can impart a sort of "metallic, robotic" sound to the music if you use it too enthusiastically.

If you do want to reduce noise using this technique, you must of course do so before trimming away the "dead space" (described in the next section) which contains the "noise fingerprints" you need to sample.

Another package which deserves a mention is DCart. This has a fairly good dynamic noise limiter, which varies the amount of hiss reduction based on the amount of high frequency signal that is present. When there is a lot of high frequency energy, the amount of hiss reduction is small; this takes advantage of the fact that the high frequencies that are present mask the hiss. When there is little high frequency content, the amount of hiss reduction is high, and the loss of what little high frequencies there are isn't very noticable. (This technique is basically similar to the the old Philips "DNL" hiss reduction system, as used on their cassette decks back in the 1970s). It can work remarkably well, especially on "busy" music, although it pumps badly on some kinds of signal (eg. solo piano).

Trimming Out Unwanted Sections and Fading In & Out

These are essential steps, and can be done easily using a wide variety of WAV file editors, such as GoldWave or my own shareware Wave Repair can also trim off unwanted sections. Try to get the start of the WAV file as close to the beginning of the music as possible, leaving perhaps a quarter second in reserve. Once you've trimmed this excess at the start, edit the first few samples to make sure they are zero on both channels and then fade in the next few samples (making sure you get to full volume by the time the music starts); all this messing about is to get a nice clean start to the CDR without a click. The same procedure is required at the end of the LP, although here you should aim for a longer, gradual fade out. I like to add a little extra silence at the end; this is because some CD players make quite a bit of mechanical noise at the end of a CD (eg. relays switching, laser sleds parking, etc), and I prefer this not to happen the instant the music finishes.

Removing Clicks, Pops and Crackle

Even the best LP will have some minor clicks that you'll want to remove. Some records in bad shape will have a constant background of crackle that you'd like to reduce.

Before going in to detail, I need to make a point about the dangers of buying clean-up software "on spec". Audio restoration is by no means an exact science. No program is going to work perfectly, and the pros and cons of each one vary enormously. You should never pay for audio restoration software unless you've had a chance to try it out and check that it does what you need. Any product which does not have an evaluation version available for download should be treated with suspicion: what does the manufacturer have to hide? You wouldn't buy a car without taking a test drive, so don't do it with software.

I have in the past had my fingers burned buying software which didn't live up to the promise (Spin Doctor, bundled with earlier versions of Roxio's Easy CD Creator). So I now refuse to buy anything if there is no evaluation version available. This policy means that I have not evaluated (and therefore cannot give advice about) three fairly well-known packages: Steinberg Clean, Magix Audio Cleaning Lab, and Roxio LP and Tape Assistant.

OK, on to the task of how you might go about reducing the annoyance value of clicks, pops and crackle. Removing these kinds of noises without adversely affecting the music is difficult. There are a number of packages on the market which claim to do so automatically, and their number seems to be growing on an almost daily basis. I have tried the following: DCart, DART Pro, CoolEdit Pro (now renamed Adobe Audition), Sound Forge (now acquired by Sony), Sound Laundry, Spin Doctor (an older program that used to be supplied by Roxio that appears to have been superceded by a module named "LP and Tape Assistant" - which I have not evaluated - in the latest version of Roxio's Easy Media Creator), Groove Mechanic, ClickRepair, WAVclean, Wave Corrector, Wave Repair (written by me, so take what I say about it with a suitable dose of suspicion). They all suffer from the same basic problem: they sometimes work very well, and other times they actually make things worse.

You can try fiddling with the parameters, but this rarely results in any significant improvement. Some of them have so many configuration parameters that it's well-nigh impossible to try them all out, especially since they perform their processing so slowly.

DCart, Sound Laundry, and Wave Repair are better in this respect because they have a realtime preview mode which allows you to adjust the parameters while listening to their effect.

Sony's Noise Reduction DirectX plug-in seem to give the best results of them all (or at least it did when it was a Sonic Foundry product, but I haven't revisited it recently). However, this plug-in costs $280, and can't be considered good value from a purely vinyl restoration perspective. Setting aside the price for a moment, on the plus side Sound Forge's Noise Reduction plug-in executes quite quickly, and has a realtime preview feature which should make setting the parameters much easier. If you are able to afford the price, this plug-in will probably enable you to achieve results as good or perhaps better than by any other automatic means, and with much less effort.

ClickRepair is a recent new product that I have been quite impressed with. It seems to make a better job of removing larger clicks than most other automatic declickers. The interface is a little unusual but is fairly easy to learn.

WAVclean, while not working in real time, allows you to listen to the results so far while it's still processing the remainder of the file.

Wave Corrector (which again doesn't work in real time) has detection and repair algorithms which seem to be rather more effective than many, so I feel it is well worth investigating. A useful feature is that it allows the user to review and adjust the correction of each individual click. At the moment I personally feel that this is the best affordable automatic declicker available.

Groove Mechanic is another tool which doesn't work in real time, but whose results are sufficiently good to warrant a recommendation. Fortunately it has few adjustable parameters, so you can't waste huge amounts of time fiddling with them in a futile attempt to find the best settings.

Adobe Audition (ie. what used to be CoolEdit Pro) has a built-in declicker which works rather well, but there are two drawbacks: the program itself is quite expensive; and the declicker does not run very quickly. There is a third party plug-in available called ClickFix which works very much faster than the standard declicker, and which offers similarly good results (albeit with a different set of compromises). The ClickFix plug-in also works with the original CoolEdit (both Pro and 2000 versions) if you happen to have these older programs.

Another product with a good reputation is Steinberg's WaveLab (some professional users regard it as superior to Sound Forge), but I have not evaluated it.

The bottom line though is that there is as yet no automatic way to remove all the clicks and pops without also affecting some aspect of the music. I perform this step manually in most cases, by listening to the waveform, homing in on the clicks, and redrawing the wave shape with the mouse, interpolating out the defect, or pasting over a replacement section of wavform from nearby. When doing this, it is best to monitor on headphones as they are far more revealing of clicks and pops than loudspeakers. Two programs with the ability to manually redraw the waveform are GoldWave and Wave Repair.

Many people have asked me for tips about how to find defects in a waveform. The best advice I can give you is that you'll learn through experience. This may sound like buck-passing, but actually getting in there and playing around with WAV files teaches you more than anything you can read. You need to acquire a gut feel for what the various audible defects look like on the waveform, and the best way to do this is with practice. As you gain more and more experience, progress becomes faster and faster.

Having said all that, I can pass on a few tips:

Another type of vinyl artifact you might want to remove is distortion due to damage caused by previous mistracking. Manually redrawing waveforms certainly doesn't get you very far with this. I have found that this kind of distortion can sometimes be removed quite well by two of the packages mentioned above. Sound Laundry's de-scratcher (using only the de-crackle facility, leaving de-click switched off) can give good results, with only subtle artifacts (the worst aspect is that vocal sibilance tend to be emphasised). WAVclean usually removes even more of the mistracking distortion than Sound Laundry, but its artifacts are rather more obvious, and I can only describe them as imparting a "hollow" sort of characteristic. I have also on occasions been able to reduce mistracking damage using parametric EQ with a very deep notch filter at a fairly high frequency (eg. around 15kHz). This dulls the frequency balance, so a compensatory lift somewhere around 4kHz is needed to restore some of the lost "sparkle"; it's not perfect but it can be an improvement. My opinion is that GoldWave has the best parametric EQ at an affordable price.

Recommended Automatic Declickers
If you insist on being lazy and using an automatic declicker, then here is a list of packages that I consider are worth investigating. I'll divide the list into two types. Those capable of real-time preview have the advantage that you can listen while you adjust the settings, which makes finding effective settings that much less frustrating: Other packages which don't have real-time preview can be frustrating to use, but some give results good enough that the effort is worthwhile: None of the packages successfully repair really big pops, which are best tackled manually. Note that it is best to do this manual fix up before running an automatic declicker. This is because big pops can confuse the declicking algorithms, often resulting in their replacement with dull thuds and splats which are far more difficult to isolate than the original pops, thus making them harder to fix in the long run.
An Interesting Approach to Decrackling
I recently came across a suggested method of decrackling that is definitely worth passing on. I take no credit for this method; I first saw it described on the AudioForums website by someone calling themselves "Younglove". It appears that the original thread is no longer online, but Tom Sherman has found
an archive of it and kindly passed on the link to me.

The procedure briefly is this:

  1. Get a noise fingerprint from the WAV file to be decrackled. In other words, find a section that contains only noise and light crackle, but no music.
  2. Use the noise fingerprint to do a noise reduction over the whole file, but keeping just the noise (rather than the music minus the noise). You need to do a fairly brutal noise reduction. What you end up with is the noise, the light crackle, and a bit of the music.
  3. Save the noise that's just been isolated, either in a file or a clipboard.
  4. Run a declick operation over the noise. Be fairly aggressive, so as to find all the crackle. You now have the noise minus the crackle.
  5. Mix-paste the noise that you saved in step 3 over the result of the declick, but invert the saved noise that you're pasting. This causes the noise to cancel out, leaving just the crackle, but inverted.
  6. Now mix-paste that inverted crackle back into the original file. Because the crackle is inverted, it cancels the crackle in the original file.
It really does work rather well, but remember that it only works for background light crackle; it doesn't deal with big pops and clicks.

So how does this work? My view is that the reason decrackling is so hard to do is because the clicks that constitute the crackle are of low amplitude, and are easily lost within the surrounding music: this makes identifying them very difficult. Once you've isolated just the background noise & crackle, the click detection algorithms have a much easier task, so they find the genuine clicks more successfully. The quality of the noise reduction really isn't that important, and the declicking algorithms can be less sophisticated since their task is greatly eased.

Younglove described the process using CoolEdit, and it is certainly very straightforward using that package since you can set up a script to do it, but it is a very slow operation. (A very old machine, which had a 350MHz AMD K6-2 CPU, took about 6 hours to decrackle one LP using this method. Then a 1.2GHz Athlon CPU took about 50 minutes. My current Athlon XP2400+ takes about 30 minutes). In principle the technique will work with any packages that support the necessary steps. The only program I know of which has a built-in decrackling facility based on this technique is Wave Repair.

Equalisation

Some LPs do suffer from high frequency dullness, and it's worth giving the top end a little boost. I keep on hard disk a short section of music (extracted digitally from a CD) which I consider to have ideal tonal balance and dynamics when played back on my stereo system, and use this as a reference against which to compare work in progress. The most I've ever put on is about +6dB from 5kHz upwards; this is usually only necessary on reissue LPs that were probably pressed from "high-mileage" stampers. In general, it's best not to fiddle too much with the balance chosen by the people who originally made the LP.

Normalisation and Compression

Normalisation is a procedure that ensures the WAV file peaks at the maximum possible value. If for some reason you recorded at too low a level, then normalisation is probably worth doing.

Note that normalisation does not guarantee that all tracks will sound equally loud; the perceived loudness is equally influenced by the dynamic range of the music. Compression can be used to squash the dynamic range which makes the music sound louder. It also tends to sound more "punchy". Applying differing levels of compression can be used to balance the loudness of tracks from a variety of sources, but be aware that excessive compression, while sounding initially impressive, can rob the sound of its subtlety.

Some packages I can recommend which provide equalisation, normalisation and compression include GoldWave, Wave Repair, and DCart.

One situation in which normalisation and compression are likely to be useful is when you are compiling a CD from a variety of sources and wish to make all the tracks sound equally loud. The approach to take here is to normalise all the files, select one as a reference, and then apply the appropriate amount of compression to the other files so that they sound as loud as the reference. This is easier said than done; finding the appropriate compression settings is largely a matter of trial and error. I have written a shareware program called Volume Balancer which automates this process. I've deliberately made it easy to use; having selected the files to be processed, a single button press does the job. There are some other programs around (eg. Audiograbber) which give the user more control, but require that you adjust a variety of settings.


Burning the CDR

Splitting Tracks into Separate WAV Files

Depending on your choice of CDR burning software, you may need to split the individual tracks into separate WAV files. This can be done with a wide variety of WAV file editors, but the task is much simpler using either
CD Wave or Wave Repair.

Using a Cue Sheet to Identify Tracks

On the other hand, you may have a CDR burning package that will place track (and maybe index) marks within a single WAV file. In this case, you will need to prepare a suitable definition of where those marks should be, in a simple text file called a Cue Sheet. As with track splitting,
CD Wave and Wave Repair make the creation of cue sheets simple. Note that if you wish to set indexes as well as tracks, Wave Repair supports them but CD Wave doesn't.

Stripping Out Headers and Trailers, Padding Blocks

I've never come across one, but have heard rumours that some CDR burning software fails to ignore the WAV header, which must be stripped from WAV files before burning. More likely is that an incorrect WAV header might not be noticed by the CDR burning package, which thinks it is audio data and puts it on the CDR. Some WAV file editors place housekeeping information at the end of the WAV file, and this too may need to be stripped depending on the burning software you use. There is a utility called StripWave which can help here, and can be found at
Mike Richter's site.

The Issue of CD Block Size

CDs are organised in "blocks". Each block is 1/75th second (which equates to 2352 bytes of data). A track on a CD must contain an exact number of blocks when it is written. Therefore, if the audio data in a WAV file is not a multiple of 2352 bytes, the end of last block might be left as garbage, resulting in a small click on playback. Most burning software will pad out the last block with zeros. The way to avoid any problems due to this issue is to make sure that all your WAV files are an exact multiple of the block size. Packages which split tracks into separate WAV files know about this, and ensure that the splits are made on block boundaries.

The Actual Burn

This is pretty straightforward. Most modern CDRW drives now include buffer underrun protection so that you don't need to worry too much about interruptions to the data flowing to the burner.

Most blank CDR disks are optimised for fairly high speed burning. Many are not even guaranteed to work at less that 4x. It's probably best not to burn at the absolute maximum possible speed (often 48x or 52x), as at these speeds the error rates can begin to creep up. Burning at 16x and 32x seems about optimum for audio discs in most burners. But by all means experiment to see what best suits your equipment.

Modern Ultra-ATA and SATA hard disks can support enormous data rates - typically up to 50MB/sec. There is no problem in them keeping up with high speed burning, provided that they are not running in PIO mode.

Some people will claim you need to regularly or occasionally defragment your hard disk, but modern disks have such low seek times that I don't bother with this any more, and I've not had a coaster yet.

Track-at-once burning can be used, and with the variable gap capabilities of some hardware and software can be made to approach disc-at-once results, but frankly all this fiddling about is just skirting around the basic issue, which is that audio discs are best made in disc-at-once mode, period.

Regarding CDR burning software: for audio CD creation, I used to recommend Goldenhawk's CDRWin. However, it has come to my attention that a lot of people are having difficulty with this company. Approach with care.

A very nice freeware program for burning audio CDs is Burrrn. It's simple to use and generally works well.

Roxio's Easy CD Creator is bundled with many CDR drives, and its basic disc writing engine is very solid, provided it works on your system. (There have been many stories from people who were never able to get Easy CD Creator working, and the general conclusion seems to be that it will either work straight out of the box, or it'll never be right). Although it is somewhat lacking in flexibility, it is fine for creation of straightforward audio CDRs. Two other packages which have good reputations are Nero and Feurio, but I have very limited experience with them. A package called Exact Audio Copy, although mainly known for being perhaps the finest digital audio extraction program available anywhere, also includes a CD burning capability which I'm informed works very well. Another CD burner I have been made aware of is Ace CD Burner, which as well as being able to write audio CDs, also includes CD ripping and MP3-to-WAV decoding. However, I have never used this program so cannot comment on it.


Useful Links

Other Sites with Relevant Information

www.a-reny.com/iexplorer/restauration.html Allen Reny's notes about Restoration using CoolEdit
www.designcontest.com/show/lpcdr-be Bohdan Zograf's Belorussian translation of this page
openspacelands.com/audio/ Dimitar Teykiyski's Bulgarian translation of this page
www.joergei.de/lp2cd/index.html Joerg Eisentraeger's notes (in German)

WAV File Editors

www.goldwave.com GoldWave
www.adobe.com Adobe Audition
mediasoftware.sonypictures.com Sound Forge
www.steinberg.net WaveLab
www.cdwave.com CD Wave
www.polderbits.com PolderbitS
www.waverepair.com Wave Repair

Soundcards and USB Devices

www.creative.com Soundblasters
www.edirol.com Edirol (Roland)
www.tascam.com Tascam (Teac)
www.terratec.com Terratec
www.pcsound.philips.com Philips
www.tbeach.com Turtle Beach
www.digitalaudio.com DAL (CardDeluxe)
www.echoaudio.com Echo
www.m-audio.com M-Audio (aka Midiman)
www.pcavtech.com Reviews of Various Soundcards

Music Restoration Software

www.diamondcut.com DCart
www.coyotes.bc.ca Groove Mechanic
www.algorithmix.com Sound Laundry
mediasoftware.sonypictures.com Sony Noise Reduction
www.wavecor.co.uk Wave Corrector
www.kagi.com/clickrepair ClickRepair
www.waverepair.com Wave Repair
www.excla.com WAVclean

Miscellaneous

www.burrrn.net Burrrn CD writing software
www.roxio.com Easy Media Creator CD writing software
www.feurio.de Feurio CD writing software
www.ahead.de Nero CD writing software
www.exactaudiocopy.de Exact Audio Copy DAE & CD writing software
www.cdrfaq.org Andy McFadden's CDR FAQ
www.mrichter.com Mike Richter's CDR site - links to many goodies


Alternatives to Using a Computer

It only makes sense to use a computer if you're planning to try and clean up the signals on your LPs. If you're happy with the way they sound, and you just want to transfer them to a more convenient medium or to preserve them, then involving a computer in the process is fairly pointless.

If you do want to clean up your LPs (ie. remove noise, clicks and pops) then a computer is really the only affordable way. (There are mega-expensive professional hardware units, such as the CEDAR range, that will do the job but these are totally outside a hobbyist's budget).

If you don't want to use a computer, the choice of archival medium is quite wide: