The Beatles, Remastered - some hopes, fears and predictions

The Beatles' digitally remastered catalogue will finally be released, in it's entirety, in just over a weeks time. As a complete Beatles nutcase, I can't help but be excited about this - but I'm also slightly nervous. 

I've written before about why I love the Beatles' music so much - and, in particular, the way that they worked with producer George Martin.

So, the idea of lovingly restored re-issues of these classic albums, revealing even more detail and magic, is exciting - whereas, the thought of heavy-handed processing or fashion-led mastering (can anyone say "scooped mids" or Loudness War ?!?) makes me nervous - especially when spokesmen have said the new releases sound "louder and brighter" than the originals.

Will these re-issues reveal the original masters in a new, inspirational light ? Or, will they be yet another cynical re-hash of music we already own ? Here are some of my hopes, fears, and predictions for this release.

Hopes

• Better transfers Digital audio has come a long way since the eighties, when many of the original Beatles CDs were released. In particular, analogue to digital converters have come along in leaps and bounds. So, there is a distinct possibility that even a flat transfer of the original tapes would sound significantly better than the original versions
• Sophisticated restoration Even more than converters, restoration technology has improved immeasurably over the years. Without a doubt the tools used will be made by CEDAR, who effectively wrote the book on this stuff, and they can achieve quite incredible feats - fixing problems with the original sources like hiss and distortion, without any of the undesirable side-effects that some of the older technology involves
• Sensitive enhancement Make no mistake, the original CDs sound pretty good already - but that doesn't mean there isn't room for improvement. Not massive changes, but great mastering should be constant proof that "the whole is greater than the sum of the parts", and I hope these releases will be perfect examples of this. 

Fears

• Heavy-handed processing The last Beatles re-issue I listened to in the mastering studio was the "Blue Album" - which sounded great, and incredibly clean. So clean, in fact, that we hooked out the original CD release of Abbey Road, and compared the two. Sure enough, the track we chose ("Come Together") had been de-noised - ie, the hiss had been reduced. Which I found an odd decision. Don't get me wrong, it's not that there were any unpleasant side-effects (artefacts) from the process - it's just that it wasn't that hissy to begin with. As George Martin has observed, the original 2-inch master tapes of these albums are incredibly clean - the only noise really comes from tracks where multiple reduction passes have been carried out.
  
• Too loud No surprises I'd be interested in this issue ! But, you may be surprised to learn that I've nothing against the idea of making them louder, necessarily - just not unnecessarily so. The fact is, a certain amount of EQ, compression and limiting would certainly have been used in the original vinyl cut of these albums, and the goal of modern CD mastering should be to achieve a comparable result on CD. In fact, another reason that the original CD releases are considered to sound "cold" by some people may be because they were made from the final mixdowns rather than EQ-ed production masters. This is a common problem with early CD releases - it removes a generation of analogue tape, theoretically getting a cleaner transfer, but also risks missing out on some of the positive benefits of the vinyl pre-mastering process along the way.

Now know you know the things I think might be in store for these releases - finally I thought it might be fun to make some predictions about we will actually hear on September 9th

Predictions

• This will be a low-level, anti-loudness war release Despite some speculation to the contrary, I'll be amazed if the levels on these are high by today's standards. The original releases had plenty of headroom, so I'm sure they will be at a higher level than that, probably with some gentle limiting - but these CDs will sound just as dynamic as the original releases.
• The sound work will be subtle & tasteful - perhaps not even going far enough EMI's mastering studios have a track record of appropriate, restrained work, and I don't expect the Beatles' remasters to be any different. In fact, if anything these may sound too close to the originals for some - for example, fans of the "Love" mashed-up versions may be underwhelmed.
• It will have been extensively restored and de-hissed - too much so, for some tastes As a mastering engineer, this is the aspect I'm most curious about. I have little doubt that the masters will have been painstakingly, exhaustively restored - how else could they have spent four years working on these releases ? The question is, how successful has it been, and crucially, how necessary was it ? Have they gone to the lengths of re-making all the reduction mixdowns digially - for example in "Strawberry Fields Forever" ? Will it have been worth it ?

But my final prediction is simpler and clearer - these remasters are going to sound great. The original CDs sound excellent - these can't fail to sound better ! And personally, I can't wait to hear them.

What are you expecting from these releases ? How do you think they will sound ? Will we be able to even hear the difference, or is it just a cynical ploy to cash in on the release of the "Rock Band" game ?

Update #3 - Most reviews seem positive about the remasters - if all goes well I'll have some feedback for you early next week. In the meantime, here are some interesting links about the released CDs:

Beatles Remastered 2009 (from Mix Magazine)

Mono or Stereo ? Help ! (Nice comparison of the two box sets, with samples)

Beatles fans deserve more in the remastering department (A less positive take on the new versions)

Update #2 - Lots of requests for opinions about the final release coming through - I'll posts something as soon as I can !

Update - thanks for all the great comments on this post ! It turns out I was right about the use of CEDAR, but much more interestingly their ReTouch software was also used in a far more radical way - to remove entire instruments from the mix for the Rock Band game:

Using CEDAR ReTouch in creating The Beatles' Rock Band game

We use ReTouch for traditional restoration tasks, but removing complete instruments - wow! Hats off to Giles Martin for that idea.

Meanwhile here's an article about the making of the game from Wired magazine, if you're interested:

The Beatles Make the Leap to Rock Band

And, here's another article, this time from the New York Times

While My Guitar Gently Beeps

Thanks to Thomas Matteo, dk and Various for the links.

Dinosaur Jr mastering fault - recalled for being too loud

This is NOT what you want your album to look like when assessed using the TT Dynamic Range Meter. This is what a dynamic range of 2dB looks like, and it sounds like shit. In my opinion. And almost everyone else's, too.

And with the new Dinsoaur Jr CD, "Farm", we now have another example - but this time, there's an interesting twist.

Mastering engineers are unanimous in their verdict that music sounds best with a dynamic range (DR) value of at least 1o dB. 

Both TurnMeUp.org and DynamicRange.de argue for DR14 or higher, for example.

In stark contrast, the song "Plans" from the European release of "Farm" by Dinosaur Jr measures... DR2. (2.1, to be exact)

"The Day That Never Comes" from "Death Magnetic" by Metallica is also DR2, (2.6) and to be honest, they sound quite similar in one way - both are massively distorted.

What makes the Dinosaur Jr CD different is that the record company have recalled it, saying the European release has been made too loud by mistake:

Dear Dinosaur Jr. Fans,
Please note that on the European CD version of the Farm album there is an audio problem. This occurred while duplicating the original master in a duplication studio. The problem occurred when the duplicate was produced, as the software program used for this duplication ‘doubled’ the sound layers. This resulted in a 3dB increase in the overall sound volume.
If you have bought a CD of Dinosaur Jr.’s Farm album in a European shop with the bar code number 5414939004926, and you would like to exchange it with a good version, please go to this site. 

So first of all - hats off to the label for coming clean and admitting the mistake, and offering clear and simple advice for swapping faulty discs ! 

Second, a collective European sigh of relief that the way this CD sounds wasn't deliberate. Don't get me wrong, it's still very loud, and would benefit from some more room to breathe dynamically - but it's not DR2 bad. (The US release measures DR6 - 6.3, to be exact)

But finally, some observations and questions. The statement above says that there is a level difference of 3dB between the European release and the intended level, but this didn't sound right to me, so I did some experimenting.

I had to clip the US CD version by a massive 6dB to get the levels (and distortion) to match those on the European release.

This makes perfect sense - a 6dB boost in level is exactly what you would expect if the "software program used for this duplication ‘doubled’ the sound layers" as the website says.

The number on the website is probably just a misunderstanding, since the label are being very upfront about everything else - or possibly a "rounding down" of the difference in DR values (6 vs. 2). But unfortunately the statement is already being misinterpreted - for example, in his Guardian piece, Sean Michaels says

though three decibels will make a noticeable difference, it is far from the realm of road drills or jet engines. Instead, the difference between good and "faulty" copies of Farm will likely be a matter of "loud" versus "a little too loud"

Personally I would disagree that even 3dB of hard clipping would only be "a little too loud", but the actual 6dB difference has resulted in a massive amount of distortion which is clearly audible and very unpleasant. The waveforms tell the story as usual:

(For those who are interested, clipping an already mastered track sounds far worse than clipping un-mastered mixes. Everything is already maximised and pushed to the limit, so 6dB of clipping is pretty much a sonic disaster.)

I just hope no-one chooses not to get their CD changed, based on comments like the Guardian one ! 

In conclusion, this can hardly be called a victory in the Loudness War, but at least it's not a backward step, as some European Dinosaur Jr fans must have originally feared.

If you think modern CDs are mastered too loud, please sign up at TurnMeUp.org and DynamicRange.de - and write to complain about any albums you think sound bad. And you are always welcome to sign up for free updates on any posts here, if you like - or connect with me on Twitter.

DIY Mastering Part 5 - How loud is Too Loud ?

As regular readers of this blog will know all too well by now, I am firmly opposed to the so-called CD "Loudness Wars", where everyone tries to get their CD louder than anyone else's by pushing the recorded level higher and higher. This is ultimately a self-defeating process - the CD spec defines a mazimum recordable level, and the harder you push your music up against that level, the more squashed, flattened, crushed and ultimately distorted it gets. Meanwhile there is far less scope within the tracks on the CD for the contrast needed for a satisfying musical result.

BUT as a mastering engineer I spend a lot of my time lifting the level of people's music so that it can compete with the high levels of other CDs out there. And, as I've said in a previous post, I feel that this is actually a positive step for most albums.

How do I reconcile these two apparently contradicting views ? The answer is something I've also said several times before here:

Louder is Better, but Too Loud is Worse

By which I mean - every track (and group of tracks) has a "sweet spot", where it's loudness (and by implication compression, level, EQ etc) is just right. It sounds the best it can be. If it's not compressed enough, then quiet passages won't have enough presence, the mix may not "gel" or have enough impact, detail may be lost, and loud passages will make you wince. Whereas if it's too loud and compressed it can sound squashed and dull (meaning bland and lifeless, not lacking treble) and ultimately fatiguing.

If the idea of using compression on a mix surprises you, it's worth knowing that as a rule of thumb people tend to like quite loud, compressed music, especially for pop and rock. Rick Rubin, who produced Metallica's latest album "Death Magnetic" (currently being heavily criticised for it's excessively-squashed, distorted sound) said in an interview from 2004:

I wish I had examples here to play for you. If I knew we were going to talk about this I’d go through the library and find examples. Ultimately, if you listen on a car sound system or in the mainstream place where most people listen to music—cars, boomboxes sound systems you get at (chain stores), and if you “A/B” the less compressed version to the more compressed version, you pick the compressed version.

And he's right ! He also says, in response to a question about things sounding better on the radio:

Sometimes actually, if it’s too loud, it sounds worse on the radio.

And again, he's right. Sadly, this is exactly the case with Death Magnetic. Clearly this is a delicate issue, and one that even the most respected engineers sometimes misjudge. Music needs just the right amount of compression and level, based on the style of music and the original recording.

So, how loud is Too Loud ? Where do we cross the boundary from sweet-spot into overcooking ? The answer of course is -

Something is Too Loud when it starts to sound worse

But what is worse ? Everything is subjective. Rubin obviously thought Death Magnetic sounded good when he was working on it - perhaps he still does. Lars from Metallica has no problem with it, but I and many others think it's a great shame that so much distortion had to be introduced.

Loudness Measurements

Ultimately the only real way to judge this is to use your ears, but for what it's worth, here are a few facts and figures. I have analysed the loudness of several tracks using a free Mac utility called AudioLeak to measure their long-term A-weighted RMS level. RMS stands for "root mean square" and as applied to music roughly describes the loudness of a musical signal. A-weighting improves on this by taking into account the fact that the ear is less sensitive to bass and treble when judging loudness, and provides a better guide to how loud we think things. A track of equal "raw" RMS level but with more bass won't sound quite as loud, for example, and so will have a lower A-weighted RMS.

Here are some example A-weighted RMS level measurements, with raw RMS in brackets - they are long-term measurements, ie. average values over an entire track. The highest theoretical value possible is zero, and slightly confusingly they are measured down from there, so -10 is louder than -12, for example. So, with the loudest at the top, we have:

-8.6 (-6.2) Oasis - "Some Might Say": Severe clipping distortion
-8.9 (-4.9) Metallica - "TDTNC" (CD): Massive distortion & clipping
-10.4 (-7.7) Feeder - "Pushing The Senses": Heavy clipping distortion
-12.7 (-7.7) Metallica - "BB&S" (Mystery Mix): Slight source clipping
-14.0 (-10) Katatonia - "Consternation": Awesome (clean) sound, massive choruses
-15.3 (-13.1) Sugar - "Fortune Teller": From 1993
-21.8 (-16.9) Metallica - "TDTNC" (GH3) Needs to be louder !

There are plenty of interesting things to be seen looking at these numbers - firstly, the Oasis track actually measures fractionally louder than Metallica ! However by looking at the raw RMS values we can see that in brute power terms Metallica has a higher level - they just have more low-frequency in the sound than Oasis, so the A-weighted value doesn't reflect that. This higher raw RMS may also explain why the distortion on the Metallica tracks is even worse than on Oasis.

Looking at these tracks it would seem that with care the A-weighted RMS can actually be pushed as high as -12 dBFS without obvious distortion. Whether the result is satisfying musically, the numbers can't tell us, though. In my opinion the two best-sounding tracks here are Katatonia and Sugar - "Copper Blue" was a loud album for it's time, but look how things have changed. (By the way examining some SRT masters, the A-weighted RMS typically hovers around - you guessed it, -14 to -12 dBFS)

So, is the answer to "how loud is too loud" actually "any higher than an overall level of -12 dBFS RMS, A-weighted" ?

Well, if we're judging "too loud" to mean "the onset of distortion", then for guitar-driven rock music, yes, maybe. However other genres may suffer more or less and we need to bear in mind that rock is a highly compressed, distorted genre to begin with. I prefer a more dynamic sound personally, so I would pick a level closer to -14 - if it suits the music. Once again, at the end of the day we need to use our ears to make these judgement calls.

Understanding Loudness Measurements

It's also interesting to think about what these numbers mean. The Katatonia track is only 2dB (RMS) quieter than the "Mystery Mix" of Broken, Beat & Scarred", but still has more punch, weight and impact, to my ears. This difference is vastly more apparent comparing to the Metallica CD, and looking at the numbers we can see why. Katatonia has maximum RMS of -8 dB, in the track, compared to an average of -14, giving it a "loudness range" of 6dB.

Compare that with the "Death Magnetic" track. The highest raw RMS level in the track is -2.5 dB. But the average is an eye-watering -4.9, allowing it a range of only 2.4 dB. So the loudest parts can be only 2.4 dB louder than the rest of the track. Katatonia has almost three times the loudness range to play with. No wonder TDTNC sounds flat and lifeless by comparison, whereas when the chorus kicks in on "MyTwin" the impact and buzz it generates is huge. And with almost 10dB to play with, it's obvious why the Guitar Hero version has so much more punch and life - and in fact in my opinion, it would benefit from some EQ and being at a higher level and more compressed, to get it into the "sweet spot". This is why despite preferring the reduced distortion, some listeners still find it lacking.

Ultimately the decision about when the music starts to suffer at the expense of level is one of taste, and requires a judgement call by all concerned. However looking at RMS levels as we have here can be very revealing for a mastering engineer, so I strongly recommend you experiment with AudioLeak or another form of loudness metering - like all mastering facilities we use them constantly here at SRT when mastering. I also recommend you stick around the -14 dBFS A-weighted RMS level to ensure that your CDs are both competitive but also loud-sounding in their own right.

Metallica "Death Magnetic" Yes, it IS clipping...

This is a very brief post with another image. (I know some people don't find pictures convincing - in that case please see the YouTube video I linked to in my last post, where you can clearly hear the effects of the distortion.)


I have read people deny that the CD is clipped. Here are closeups of waveforms from the UK release of the CD (top) and the GH sample I was sent (bottom).



As you can see, the CD is clipped (the tops of the waveforms are "squared off" ) whereas the Guitar Hero version on the bottom is not. This is the cause of a least some if the distortion people are hearing.

However as I mentioned in a previous post, digital clipping alone isn't enough to make the album sound as distorted as it does. So yes, the album is clipped, but in my opinion the distortion probably results at least partially from an earlier stage in the process as well - presumably the mix.

Mastering Techniques - Using A Compressor - Part 2

This is Part 2 of a series of posts about using compression in mastering - the first post is here. For a more general introduction to using compression, click here.

Choosing the right compressor settings

Now your ears are focused on what the settings are doing, where should you set them ? Easy:

Adjust the controls until it sounds right

OK, that's next to useless, I know. "What sounds right" varies on the instrument or mix, the genre and taste. There is also a big difference between compressing an instrument in a mix and compressing a whole mix.

Compressing an instrument

For example, compressors are commonly used to even out very dynamic (spiky) intruments in a mix, like a snare drum, say. A snare note has a big spike at the beginning (the transient) created when the stick bashes the skin, followed by a longer sustained sound as the body of the drum resonates. If you push this uncompressed signal too high in the mix, the initial transient may start to sound annoyingly loud and percussive or even distort, if you push it into the red. As a result you can't hear enough of the "thump" of the drum to give it weight and impact.

To minimise this effect, you can compress the signal, using:

• a fast attack time - as soon as the signal starts to get loud, the compressor quickly starts to take effect
• a high ratio to have quite a dramatic effect reducing the spiky transient
• a fast release time to allow allow the compressor to "relax" quickly once the spike has been controlled
• a fairly high threshold so the ring of the drum is not compressed as well as the transient

With a little tweaking, the result should be a much fuller, punchier snare sound - the compressor jumps in quickly (fast attack) and holds back some of the big spiky transient (high ratio high threshold) but because the spike is very short, quickly releases again to allow the main note of the drum to sound. Overdoing it will have undesirable results though - for example if the attack time is too fast, it will remove all the attack from the note, making it sound dull and lifeless. But a bit of experimentation will soon sort this out, and as a result, the snare can be lifted higher in the mix without becoming annoying or distorting - the compression makes it louder. It also sound fuller and punchier, as a by-product.

Compressing a mix

Using settings like the ones above almost certainly won't work well on a mix, though. As a rule in mastering, the aim is for the compression to be as unobtrusive as possible. Usually we aim for a natural-sounding result, where the compression isn't easily noticed. Most final mixes have already had suitable compression used on the individual instruments, so the settings described above will probably result in something that sounds squashed and lifeless, or even pumping and distorted.

Remember in what follows that it's very common to use both a compressor and a limiter when mastering - the limiter catches the very fast transients, allowing the level to be lifted even further, but I'll discuss limiters in the next post. As far as compression goes, for a whole mix I often:

• Avoid very short attack times - and very long ones
• Use shorter release times
• Use low ratios
• Avoid large amounts of gain reduction

The medium attack time allows percussive elements of the mix to punch through, but still controls the overall signal level. If this gets too long, you'll hear the "thump-suck" effect I mentioned in the last post. Shorter release times also avoid obvious pumping, but you need to be careful. If they get too short, there won't be enough control and you may hear the compressor "bouncing" - rapidly triggering and releasing over and over, sounding crunchy or distorted as a result. Low ratios and moderate gain reduction avoid the compression becoming too ear-catching. Time for another rule of thumb:

If you compare the compressed signal with the level-matched original, it should sound better

Meaning not squashed or pumping (unless that's what you want !). You should always level-match the "before" and "after" levels before making your comparison, of course. When level-matching for comparison purposes, it's often worth using the vocals to judge the loudness. Our ears tend to latch onto a voice as the most important element in a mix, so get these as close as possible before comparing. Then listen and ask yourself questions like:

• Which do I prefer ?
• Am I sure one of them isn't louder ?
• Have I achieved what I wanted ? (ie. made it punchier, fuller, with more impact & excitement)
• Does the compressed version still sound lively and exciting, or is it too squashed ?
• Does it sound closer to similar tracks I'm trying to emulate ?
• Can I hear more of the quiet details in the mix, or is it getting "mushy" and confused ?
• Does it still sound natural ?

If you can answer these questions with a positive, you're doing well. If not, try varying some the settings and comparing again. If you still can't get a result you like, try a different compressor - or maybe it doesn't need compression at all.

All of this is very hard to describe in words of course, but hopefully by now you'll have a better idea of how compressors are used, what the controls actually do and what you should be listening for.

If you found this post useful you might also like to watch my free webinar on the more advanced technique of multi-band compression - for more information, click here.

 

Mastering Techniques - Using A Compressor - Part 1

There are still more things I want to cover in the area of general DIY Mastering, but I've decided it's time to start posting some specific information up here to help people get to grips with common mastering techniques. So this is the first in a new series of posts headed "Mastering Techniques", which will run alongside the DIY Mastering posts. I'm going to cover things like level-matching, EQ, stereo width adjustment and so on, but I think the subject most people struggle with is compression. Often people have been told that the answer to any number of problems is compression, but don't know what they're trying to achieve, or how to get there.

This post started to get much too long, so I've decided to split it into several sections, this is Part 1...

Know What You Want

In my opinion, the most important thing when using compression is to have a clear goal. You'll see lots of explanations of compression saying things like "a compressor reduces the dynamic range of it's input", but I don't find these very intuitive, and prefer the explanation I was given as a trainee:

Compression is used to make things louder

There can be all kinds of positive side-effects of this process, like making things sound fuller, richer, more controlled or punchier, but at the end of the day, especially in mastering, it's all about loudness. NOT excessive loudness, but something musically beneficial.

Mastering engineers almost always use a limiter somewhere to boost level, but the problem with this is that mixes very quickly sound crushed or distorted using only limiting. Using some gentle compression first means the limiter doesn't have to be hit so hard, giving a more natural sound. More on limiters in a later post.

The ideas here apply equally to compressing individual instruments or voices in a mix, incidentally, but you'll need different settings, usually. First we need to recognise a harsh fact of life:

Not all compressors are created equal

The best analogue compressors cost thousands of pounds. However there are some really good software plugins these days which cost far less. For example if you're looking for emulation of a traditional analogue compressor in a mix, complete with "musical" pumping, I really like Sonic Timeworks Compressor X. Would I use it for mastering ? Probably not. However there are high-quality compressors available on a DIY budget which are suitable for mastering - the TC Electronics System 6000 is a mastering "industry standard", and many of it's algorithms are available as plugins for their Powercore system, for example. Many people also use plugins by Waves or Izotope, and discussions rage about whether it's really possible to master with something so cheap, and which is better, on the Sound On Sound mastering forums and elsewhere.

Regardless of which compressor you decide to use though, they all share similar controls and concepts, and at the end of the day it comes down to whether you're happy with the result you get. With that in mind, lets dive in:

Exploring Compressor Controls

Try this experiment - we're going to overdo everything to begin with, so you get a feeling of what the different parameters do:

• Choose an instrument to compress and solo it (We'll move on to compressing a whole mix later)
• Patch a compressor across the stereo master output channel of your system
• Start with a ratio of 2:1.
• Set attack and release times of 100ms, if possible. You may have to disable "automatic" options first.
• Gradually reduce the threshold until the meters show you 4 or 5 dB of gain reduction

One of two things will have happened. Either:

• The sound will have got quieter, because the compressor is holding back the louder peaks. In this case you need to add some make-up gain, sometimes called output gain. Adjust it until the sound is a similar volume to when you hit the bypass or disable switch

Or:

• The sound will already be at a similar level, in which case your compressor automatically boost the output (make-up) gain

Now toggle bypass on and off and listen to the difference. Depending on your material, you will hear more or less difference. If you can't pick anything out initially, increase the ratio to 4:1 or reduce the threshold until more gain reduction is happening. (If you can't hear 6dB gain reduction with a ratio of 4:1 you should probably get your mastering - and probably mixing too - done by someone else !)

If your compressor has automatic attack and release times, it will probably sound OK (but a bit squashed). Even with manual controls, it shouldn't sound too bad. Once you can clearly hear the difference between the bypassed and compressed signals, you can try and figure out what it is you're hearing.

All the controls interact to give different effects, but before we get to that lets look at each in turn. First, ratio and threshold.

Ratio

Try increasing and decreasing the ratio. Higher values (4:1 etc) cause a more exaggerated effect - the compression "hits harder". Lower values are more subtle. If your compressor doesn't have auto make-up gain, you'll need to adjust it to match the bypassed version for a clear comparison. As a rule of thumb, use a high threshold and high ratio for a hard-hitting sound, but watch out for unnatural results. Lower ratios give a softer, "warming" or "thickening" effect. I rarely use higher than a 2:1 ratio.

Threshold

The threshold control determines when the compressor starts working. Lower values will give more compression, higher values give less. A low threshold with a high ratio will give lots of hard compression and probably sound very squashed and lifeless, whereas a higher threshold and low ratio will be a much more subtle. Whatever values you decide on, there is one rule of thumb worth remembering:

If the gain reduction meter doesn't return to zero several times a bar, you're almost certainly using too much compression

- because this means that the signal is being compressed all the time, and will probably sound flattened as a result. Try a higher threshold, and then higher ratio if it's not doing enough.

Attack & Release Time

Since I specified long attack and release times, you will probably hear the sound being "snatched" away right after a new note comes in, and perhaps "pumping" back up afterwards. Sustained notes are a good way to hear this. If you increase the attack and release times you'll certainly hear these effects. (For a deliberate example of this classic "thump-suck-relax" pumping listen to "One More Time" by Daft Punk). Automatic or "intelligent" settings reduce this effect, but increase the risk of using too much compression without realising it.

Now try reducing the attack time to it's minimum value. The sound will probably duck very quickly away to begin with - perhaps too fast to hear it happen, followed by the longer release back up to full volume. The chances are it will have lost any impact it used to have, especially with a higher ratio, and sound quite unnatural. Reducing the release time decreases the "pumping" effect, but as you get too short will start to sound "crunchy" or distorted.

Now your ears are focused on what the settings are actually doing, where should you set them ?

Answers in the next post.

What is Mastering ?

The art of mastering for CD and DVD evolved directly from the process of "cutting" a lacquer for vinyl pressing, and involves many of the same concepts. But what actually is it ?

Here are some possible definitions of mastering:

• Creating a production master for replication
• Achieving an optimal balance of tone and level
  
• Gaining the benefit of an experienced, impartial ear
• Top/tailing and sequencing
  
• Fixing any outstanding problems from a mix
  
• Making your music sound the best it can be
  
• Making it f-ing loud !
  

So, which one is right? Well, all of them, to varying degrees - except the last one. My favourite explanation is this one:

Mastering is the art of making a collection of tracks into an album (*)

(*) or single, or compilation, or podcast, or catalogue...

This is achieved by one or more of several techniques. As well as technical tasks like ensuring the best transfer from the source and creation of a suitable master, these may include:

• Level adjustments, often using a limiter or compressor
• Equalisation (EQ) to achieve a natural, balanced sound - broadly speaking the right amount of bass and treble, but also much more detailed adjustments, for example to remove unnatural resonance or build-up at certain frequencies, or perceptually improve limitations of the mix. Common examples might include adding "air", or "punch", or adding "edge" to guitars, for example
• Correction of faults - for example removal of clicks, pops or thumps, buzz, hum etc.
  
• Detailed sound restoration - usually only necessary on "vintage" sources, can include removal of vinyl clicks, hiss & distortion etc.
• Stereo image adjustments - this is less common, but may involve widening the stereo image, or (occasionally) adding reverb

Exactly which of these is needed varies from album to album, and even track to track. Some jobs need major surgery, a very few I've ended copying flat from the source. In the later case, did I actually master them? Yes - because I listened carefully, in a dedicated studio using exceptional monitoring, and used my ears and experience to determine that nothing extra was needed. (Actually, more often than not we can spot a source this good within a few minutes of beginning to listen, in which case we contact the artist and offer them the chance of a Direct Transfer instead, so they don't pay for something they don't need.) Deciding to do nothing at all on one or two tracks is just as valid a mastering decision as any other.

However there is still lots of room for confusion and debate. Should mastering engineers:

• Use the minimum possible processing, and keep everything as close as possible to the original material
• Preserve the artist's original vision
• Pull out all the stops to transform a source into what it always "should have been"
• Preserve the original's dynamic range and impact
• Use EQ and compression to achieve major increases in level
• Make everything fit their "trademark sound" ?

Once again my answer is "all of the above" except the last one. This may seem contradictory - surely some of them are in direct opposition to each other ? Not really - because an element of the mastering engineer's skill-set which doesn't often get talked about is intuition. With almost every source I play, I can hear where the artist or engineer was "trying to get" within minutes or seconds. I can hear what they're trying to achieve, and I see my job as trying to help them get there. Using minimal processing, if possible but if not by throwing the kitchen sink at it, and all combinations in between - always staying true to the original mix.

The issue of levels and compression is a good example of this - there are lots of easily available limiter and compressor plugins now, but many of people complain that they ruin the sound. Mastering engineers use very similar tools to achieve their results, and claim that they make things sound better. How can both be true? Partly because there is still a distinction between the tools - mastering studios typically spend thousands of pounds on a single compressor, whereas for the same money you can buy an entire suite of plugins - but also because we are constantly honing our skills to use the tools transparently, and our listening environment to be able to hear when it's working. To some extent, the skill of a mastering engineer is to achieve an appropriate level for every track , sometimes reducing the dynamic range in the process, but make it sound as if the final result is actually more dynamic. Or to make major EQ adjustments, without changing the essential qualities of the original.

So, you might ask - what's the point of paying for something that can be so subtle ? There are several answers to this:

• Often it's not that subtle ! If I'm doing my job, the mastered version will simply be better than the original, while retaining everything that was good about it.
• Where the difference is less obvious, it will only be difficult to hear when level-matched. The importance of increasing the level of a track to it's own particular "sweet spot", without pushing it over the top, is hard to over-emphasise. Doing this for all of the tracks in an album, and getting them balanced perfectly against each other in their final sequence is even more important and valuable. This needs to be done with great care and skill though - it's almost impossible to achieve this simply by pushing the level up into a plugin.
• Ideally, the differences should be subtle. A truly great mix only needs the slightest of tweaks, but even these minor adjustments, over the course of a whole album, add up until the sum is greater than the parts.

As I type this I'm struck again by the inherent contradictions of the job. It requires you to be entirely humble - I start every session by listening carefully to the source and thinking "what's good about this ?"; but also supremely arrogant, making changes to a mix that someone has sweated blood over for perhaps weeks or months. It requires deep technical knowledge, but many of the judgements made are largely aesthetic and artistic. It means knowing when something ain't broke and not trying to fix it, but also knowing when to roll up your sleeves and get your hands dirty...

What is mastering ? Has this post helped explain it at all ? Who knows...

Mastering Software Part 1 - Metering Levels and Loudness

I mentioned the Orban Loudness Meter on the SOS forums, and thought it would be good to start a series of posts here on useful mastering software. So, first up - metering apps. Several of the best editing packages include decent metering, for example Wavelab, and Audacity, but here are a few personal favourites:

•  Orban Loudness Meter Great (free!) utility includes a PPM meter, VU meter, ITU BS.1770 meter and CBS Technology Center loudness meter - it's fantastic to have access to these less common metering systems, which offer measurements of perceived loudness, which can be more useful than pure RMS. (Plus it runs well under Parallels on my MacBook Pro ;-) 
• Pinguin Audio Meter Not free but comes in several flavours, the Pro version includes an incredibly detailed spectrum analyser, audio phase correlator (more in a later post), PPM & VU monitoring plus a specrogram. Interestingly, Pinguin have done research to suggest that RMS is the most reliable way of measuring perceived loudness.
• Speaking of Spectrograms, there's Spectrogram - and Audacity has this capability, too.
• Finally, the fantastic (Mac-only) AudioLeak - an Leq (Long-term Equivalent Level) Analyzer for audio files and sound input streams. Swiftly discover the average RMS of an audio file, and it's A-weighted counterpart. Just watch out - by default it displays a combined mono value which reads higher than other applications like Wavelab - I usually use the average of the left & right values - they should be almost identical if the L/R balance is right, anyway. Also great for DVD Producers wanting to find the right dialnorm setting for a Dolby Digital encode.
• Update - here's another one - the SSL X-ISM meter. This is useful because it includes checking for inter-sample peaks. This is well-explained on the page I linked to, but briefly: strange as it may seem, when audio has been heavily limited and is peaking at (or very near to) zero, it is possible that the reconstructed analogue output actually peaks above zero. (In theory, up to 6 dB higher !) In cheaper players, MP3 encoders and other utilities, there is often no headroom allowed for this situation, and unwanted clipping can result. This meter will help you watch for this effect and avoid it. As a rule of thumb, don't allow your audio to peak higher that -0.3 dBFS.

Coming soon - how to choose a mastering studio.

DIY Mastering Part 3 - Room Acoustics, Treatment and Layout

This is too huge a subject to cover properly in a blog, but if your monitoring environment isn't working well, you'll never be able to make good mastering (or mixing) decisions, so before you start considering tools or techniques, you'll need to get the room working reasonably well. Here I'll try to give some short but useful pointers and links to good, more detailed information.

The Room:

1. Needs to be a decent size - at least 3m x 4m, say.
2. Needs to have good proportions. Square is bad, a rectangle is better unless it is twice as long as is wide. All shaped rooms have "nodes" - certain frequencies which are emphasised or minimised by reflections between the walls. The dimensions of the room determine which frequencies will be emphasised, and the goal is to spread these nodes out as much as possible, to give the most even response. There is a great free utility called ModeCalc which allows you to calculate the room nodes for a given room, and the same page has a great introduction to the subject. Ideally, you could build "splayed" plasterboard walls to give a wedge shape which reduces the nodes even further.
3. Needs acoustic treatment. Every room will benefit from some acoustic panels - you can make these quite simply yourself using high-density fibreglass ("rockwool") mounted in wooden frames, or buy them from a company like RealTraps, who run the site that the ModeCalc utility is hosted on. These "bass traps", or more accurately "broadband absorbers", will further even out the frequency response of the room, enabling you to make better mixing and mastering decisions. Foam panels may also be helpful but are far less effective, especially in the bass end, where rooms have the most problems. Egg-boxes are useless !
4. Needs the speakers in the right place. They should be on a shorter wall, not too tight into the corners, equally spaced from opposite walls. I've seen several very theoretical methods of determining this, but perhaps the best advice is to get a recording you know well, play it at your chosen reference level, and move them around till they sound "right".
5. Needs a good listening position - equally distanced from both speakers, obviously, but not in the middle of the room. Whatever the shape, some bass frequencies will cancel most strongly in the middle of the room, so it's almost always a bad mix position. If you are one third of the room length away from the speakers, you'll be off to a good start.
6. Needs the right materials. For example, Pro studios use very expensive acoustic panels to control the sound by reducing unwanted reflection from smooth plastered walls. A cheaper alternative is to put carpet on the walls, with the idea of "deadening" the sound. However this isn't always a good idea in a mastering room - since the idea is to get the best possible result for a "normal" listening environment, a certain amount of reflection in the room is important, otherwise you'll be tempted to add too much high frequency to everything. Heavy curtains are probably a better idea for controlling the "liveness" of the room, not least because you can easily change their arrangement and effect on the sound in the room.

All of the factors above affect the way your room sounds, hopefully for the better ! In a later DIY post I'll describe a few simple tests to help you check if your room sounds good.

DIY Mastering Part 2: Before You Start

Before getting into more detail, there are some ground rules to be covered. All of these are important guidelines for any mastering engineer. I'll spread them over a few posts, but we'll start with rules for before you start mastering.

1: Always use a fixed listening environment

Which means level, room, monitors - the whole thing. Mastering is the art of turning a collection of pieces, songs, tracks, into an album. (Or single, or EP...) We're trying to judge impact, pace, atmosphere, dynamics and timing ( amongst others ) - in fact, as a professional mastering engineer I'm almost trying to second-guess the artist. To make a fair and accurate judgement compared with all those other discs, we have to be 100% confident we know what we're listening to, which means eliminating variables in the listening environment. The same goes for any room used for mastering - it needs to be as good as possible.

I'm going to cover room acoustics and treatment in a later post, but the first and most significant thing to control is the level - ie. how loud you listen to the music. I have two levels I master at - one is 12 dB below the other, and I switch between them throughout a session. The exact level you use isn't critical, but it needs to be consistent. (For the technically minded, use an SPL meter and generate pink noise at -18 dBFS. In my room this corresponds to a C-weighted SPL of 79 dB SPL.)

Then listen long and hard to some good CDs. Figure out which ones you consider to sound perfect, which ones sound too loud, which too soft, which too bassy, which too bright. You might decide to use a slightly higher or lower level than I've suggested to suit your comfort or taste, but there are very good reasons for sticking close to this reference level.

You'll probably find that a large number of recently mastered "classic" albums sound absolutely fantastic at this level, and also that many of the newest sound uncomfortably loud - check out my first DIY post for more about loudness.

Once you've settled on a level - stick with it. If you work at it for long enough you'll develop an instinct for the perfect level for any piece of music, and more importantly you'll avoid being tricked by the Fletcher-Munsen effect; in a nutshell, quiet sounds appear duller and thinner - ie. if you master with your level too low the chances are you'll add too much bass or top, and vica versa.

2: Use full-range, FLAT monitors

A CD is capable of reproducing a frequency-range of 20 Hz to 20 kHz. Your monitors need to come close to this - anything they can't reproduce, you can't hear, and may misjudge. In a pro mastering room this generally means the monitors will be big, and expensive. (In most mastering-houses they may easily cost more than a family car !) So try to choose neutral, accurate speakers, with a flat frequency response - perhaps bland-sounding to some ears, because that way you know it's the music that sounds great, not the monitoring. B&W make some superb hi-fi speakers which could be suitable for DIY mastering.

Ideally you should master on different monitors than you mix on, and even in a different room. This is partly to get a fresh perspective on what you're listening to, but also it means that if there are problems or limitations with the monitors you mixed on, you are more likely to spot this. If you're going the DIY route obviously this won't be easy, but the next best thing is to listen to your mastered audio in as many different places as possible. If it consistently sounds boomy, it probably has too much bass. But problems that you only hear on one system are more likely to be to do with the setup of that system.

One good tip is to setup your home stereo speakers in the mastering room, assuming they're decent quality - since you listen to most of your music on these, you may be much more sensitive to mastering judgements listening to them. Even listening on a favourite pair of headphones can be useful. But remember the golden rule - pick two mastering levels (three at most) and only use these when mastering.

3. Use a loudness meter

As I said in my first DIY post, perhaps the most important thing a mastering engineer does (apart from put the right tracks on the CD, in the right order !) is to choose a consistent, musical level for each track. The most important tool for deciding this is your ears, but meters giving you an objective measurement of the level are invaluable. Most people will probably find it easier to use the digital metering offered by a piece of software, but I still have a soft spot for the analogue needle, or VU meter.

Whichever you decide on, the most important think to know is why bother to use a loudness meter ? Because the absolute and relative loudness' of tracks on an album have an immense effect on their perceived sound and a peak meter is virtually useless for judging loudness. The classic example is the human voice - a very quiet voice can have an extremely high peak level. It "looks" loud on a digital meter, but it sounds quiet. A VU or digital loudness meter looks much more as things sound in terms of level. If you learn how the meter relates to loudness it'll help you make good judgements in "mastering".

More guidelines in a later post...

DIY Mastering Part 1: Loudness Wars

Probably the hottest topic in mastering in recent years is loudness, and certainly one of the most important jobs for a mastering engineer is to achieve a satisfying, consistent level between all the tracks on an album. However the arrival of digital signal processors during the 90s, coupled with the perception that "louder is better" has led to the infamous "loudness wars" - a gradual increase in the loudness of albums over the years, to the point where some are hugely distorted and very fatiguing to listen to.

If you come to SRT wanting your CD loud, we'll be happy to oblige, but my own personal motto is "Louder is better, but Too Loud is worse" - meaning I believe there is a "sweet spot" for every recording where it's loud enough to "work" given the limitations of the original mix, but is not so loud that it suffers. Push something too far beyond this sweet spot and the effects are only negative.

Why is Too Loud bad ? Apart from problems like distortion, pumping or dynamic inversion, a great way to answer that question is to point you here:

www.turnmeup.org

Just check out the video for a great, simple demonstration of why louder is not necessarily better, plus a great selection of "loudness war" links at the bottom of the page.

In a later post I'll discuss how loud is "just right", and the best way to achieve it, but there's other ground to cover before then.