Background FAQ: Making better mixes, tips on compression, EQ, monitors, CDRs.
Background FAQ topics:
What is mastering?
CD mastering has a reputation as a mysterious art known only to a musical high priesthood. In fact, the right mastering can make a good recording sound excellent, and possibly turn a great one into a legend. Most discs can be made competitive for radio and in-store play.
To use an analogy - Every album has a "voice" in which the message of the artist is delivered. A strong performance and good recording technique will set the basic tone for this voice. Mastering can then profoundly affect it's impact and resonance. How? My guideline is: do what serves the music. A wide range of techniques can bring out an album's native voice. Depth, punch, sense of air and detail can all be enhanced. Vintage tube processors may work, or the latest technology could be appropriate. The solution sometimes goes against logic. Experience and a feel for the music determine the best path.
The process: Most people are familiar with the idea of recording music in a live concert or recording studio. You make tapes that store the individual performances, or takes. Ultimately these takes are assembled into a final master tape. This is sent to a replication plant, where copies are made. The process of creating the final master is called mastering. It has three steps:
Note - To CD replicators, mastering means creating the glass master disc that is used to make stampers (which are then used to press the CDs). Almost every CD plant prefers to make it's own glass masters, for quality control reasons. The glass master should be a perfect mirror image of the CDR master disc produced by the music mastering facility. In this brochure, I use the classic definition of mastering: The final creative step in producing a CD.
Why not just transfer my mixes to CDR?
If your mixing engineer is one of the rare few who can mix and master at the same time, then a straight transfer might do fine. But there are at least three reasons why professionals send tapes out for mastering:
Tube vs. solid state electronics
No one will ever settle this question, since both solutions have advantages in different areas. Either tubes or transistors can be truly excellent when the circuit is done carefully with the highest quality components available.
The best solid state circuits come close to disappearing. They tend to err in the direction of a faster, more defined, slightly less forgiving sound. The best tube designs approach perfection from the other side, with a sense of transparency and air. People consistently use the term "warmth" when describing tube sound. Tube circuits offer a wider array of options if you are trying to improve the sound, rather than just pass the signal through with no changes.
Digital designs approach the standard set by the analog solid state, but are less forgiving. A harder, closed top end feel often results from the limits set by current technology. Sense of air and soundstaging are usually somewhat compromised.
Digital & Analog processing: More on quality
1. Assume for a moment that you have a great-sounding two channel mix. Assume also that you have that mix stored to your satisfaction, either on DAT or a higher-resolution 24-bit format.
2.You need to edit the mixes into a sequenced tape, usually called a submaster or work tape. Many digital editors will do a good job if they are used correctly. This means for straight assembly editing - sequencing the tracks, crossfading between takes and cleaning up the beginnings and ends of cuts. Notice I did not say sweetening. (Ominous pause...)
3. Sweetening takes a lot of computational horsepower, using at least 24 bits of data, to maintain the integrity of the music. Many digital processing devices, including the ones built into some well-known digital editing workstations, just don't preserve enough accuracy in their computations. To be fair, many PC's and Macs are equipped with 24-bit processing cards. They should sound good, or at least neutral, but a significant number of people say the resulting master lacks the raw energy that was there in the early mixdowns. They ask what can be done to fix it. The summary? Consider using an editor to assemble your tracks, and leave the sweetening to devices that have been proven over time to be more friendly to the music.
So what are the options for processing? Some digital processors can sound excellent. Still, the better analog processors haven't been replicated digitally. This includes a number of custom tools that I use because they make the music sound right. Signal processors affect a lot of things in the music, and music is inherently an analog process. The best analog gear has a sound that a digital device cannot fully model.
To complicate matters, if a producer prefers the sound of top-shelf tube equipment, we have to go analog. While there are digital processors and software plug-ins with "tube sound" presets, its an open question as to whether they have done it right yet. Again, any two excellent engineers may disagree on this point. In the meantime, I provide actual tube processing for clients who request it, rather than a digital facsimile. All this brings us to the next point....
4. We may have to go back to analog, through some high-resolution equipment, and back again to digital to get the sounds that people want on their albums. You have added a conversion process to the signal, and theory says that the music will suffer. Technically, this is accurate. In the real world, the benefits usually outweigh the drawbacks. Test instruments will tell you one thing, and your ears may tell you another. Please remember, we are not talking about the average studio compressor or EQ, but specialized low distortion, low noise, wide bandwidth devices designed for mastering.
Also, this assumes that you use the best 24-bit outboard converters, which are capable of performance significantly higher than anything that can be stored on a CD or DAT. And when analog processing is complete, your high resolution music signal needs to be correctly dithered back to 16 bits. Dither could take up several pages of discussion. As you convert your 24-bit signal to 16 bits for CD storage, you can just truncate the data beyond 16, but quality will suffer. The better approach is to add a small amount of random noise called dither to the signal as it is converted to 16 bits. If the frequency spectrum of the dither noise is shaped so that it lies in areas where the human ear is less sensitive, the result can be a CD with an apparent dynamic range of more than 16 bits. Some techniques for dithering work better than others. Sony Super Bit Mapping and Apogee UV22 are just two of the solutions available. The topic of which unit sounds best gets technical very quickly. Every engineer has their opinion.
(Technical perspective & reality check: the average wideband RMS noise floor of mix tapes I receive is 65 - 70dB down, with variations of up to 10dB very common. This means that console noise, open midi and guitar amp channels etc. are providing dither signals well above the 16 bit noise floor, and the converters in your DAT machine may not be as terrible a compromise as you would think. 24-bit converters are worth it, but its not the end of the world if all you have is a DAT with good 16-bit converters. Make music! Let the guys in the white coats crunch the numbers.)
Every converter has a unique sound, so I keep a few proven 16-bit units on hand as well as the 24 bit hotrods. As an added measure when going to analog, I can re-clock the data stream, effectively eliminating digital jitter. Jitter is an interesting feature of digital audio that can mess up the sound of otherwise good music. The device I use has a custom manufactured ultra-stable crystal, and it can make the sound going into the analog processors actually better than the sound you heard on your mixdown tapes. The October 1993 issue of EQ Magazine has an article I wrote on the subject, if you would like more details.
So to recap, if the mixes are already stored digitally and you have digital sweetening tools that deliver the sound you want, that's great. Sometimes the detailed sound that digital is known for is perfect. It depends on your style. If you prefer the best that analog has to offer, then convert only once, carefully, since extra conversions can remove "live" feel. The most important thing is to do what serves the music.
Quality issues with CDR media
As CDR replaces Umatic tape as the common format for shipping CD masters, many mastering houses use digital editors that write the final CDR at higher than real-time speeds. This saves time for the engineer and allows the facility to generate more product. 2x speeds are common and the trend is to 4x and beyond. This practice is being mirrored at some replication plants, where glass masters are cut at faster than real time rates to maximize throughput. I have heard a number of top people discuss sound differences between CDRs recorded in real time and at higher speeds.
CDRs don't play as reliably as manufactured discs, especially on changers, car stereos and boom boxes. People have noticed variations in level during playback or crackling sounds in very quiet passages of the music, especially on high-speed copies. As manufacturers of players cut costs, the problem may even be getting worse - there's equipment out there that will barely handle a production CD. CDRs can tax this type of gear to it's limits, and strange things result. Dirty laser pickups can also aggravate the problem. (When was the last time you cleaned the pickup on your player?) So.... the bad news is that a CDR might not sound perfect on all CD players. The good news is this has never caused a problem on a master that I've produced for replication at a CD plant. If the master that I send to you for final approval sounds fine, then the plant will be able to produce discs that sound the same. The best test for a CDR disc is to play it on a high quality standalone CD player. If you want to make speaker comparisons, substitute small speakers or cheap headphones for the better speakers hooked up to the amplifier part of that system. The CDR will read accurately, and the variable will be speakers.
One possible explanation for sonic differences reminds me of the '70s trend towards mastering vinyl at half speed. When discs are mastered in real time, the media has more relative time to respond to the cutting laser. This results in a pit geometry that is more precise. When the disc is played back to cut the glass master, there is less chance for jitter and other timing-related problems to occur. A second factor is more measurable: as you increase cutting speeds, error rates sometimes go up, even though discs spinning at higher speeds are considered to be more stable. The built-in correction on the playback side should compensate for any increased errors, but not everyone is convinced. I take the conservative approach and create all CDRs at low speed, using media certified for 8x or higher cutting.
Final note: Some 80 minute discs are not as reliable to read or write as the standard 74 minute CDRs are. Consider using the 74 minute discs for your premasters.
Other mastering tools
Signal processors are like tools in a carpenter's toolbox. Spectral processors or dynamic equalizers can pull instruments out of a mix or de-ess a vocal. Exciters can boost harmonics, at the cost of making the top end grainy. There are better ways to enhance highs. I can also create surround-sound feels, using analog or digital techniques.
Vintage tube gear can "warm up" tracks, counteracting some of the effects of digital storage chains. Since vintage gear is often too noisy for mastering, I first correct the circuit and component flaws that were common 40 years ago. This keeps the clarity and the fat sound, while bringing the noise floor closer to modern standards.
When digital is appropriate, I use 24-bit hardware processors by TC Electronics, ATT/Wolfrum and others. These offer the standard suite of dynamics control, EQ and reverb. I've developed some custom DSP algorithms useful for subtle effects. I also have a full range of 24-bit software based processors, but tend to use them only where they are clearly superior - noise reduction for example.
Once you have the right tools, its a matter of deciding which ones to use. Certain combinations can make tracks sound "bigger." Which ones and in what combinations exactly? Tough to say in advance. You actually have to work with a given track. This is where mastering becomes more art than science. When you select processors, as when you select converters, the trick is to provide what the music needs, and no more.
Should I mix to analog or digital?
Given a choice, mastering facilities prefer to work with source material that is higher in resolution than the (16-bit) target media. There are two commonly available options that meet this spec: 24-bit digital files and analog tape.
Many studios now have computers equipped with CD burners, and 24-bit sound cards are available for a few hundred dollars. This makes it possible to mix directly to computer, and then burn a CDROM disc containing 24-bit stereo music files. This is the least expensive way to move your tracks into the higher-quality world of 24 bits. Common multitrack systems such as Paris, Protools, Radar, and VS1680 can also write 24-bit files.
Among 16-bit mixdown formats, DAT is the most familiar. It is convenient and sonically equal to the CD. Its worth examining the differences between this standard medium and analog tape, especially 1/2 inch stereo:
The verdict? DAT is generally considered better than 1/4" tape at 15 ips, though if you want the fat in-your-face sound of tape, analog has the advantage, especially if you have good noise reduction. If you have a 1/4" machine available, run it in parallel with the DAT for a couple of mixes, then sit back and listen to both. I have clients that prefer the analog, especially if its running at 30 ips.
If you compare DAT to 1/2" analog, the picture changes. Even when expensive outboard A/D converters are used, most folks choose the analog. My opinion is that 1/2" is the format of choice for most styles of Pop and Rock music. Many hit records are being made in this format. Once you hear it, you'll know why. While its more trouble and expense to work with and the media costs more, the results are worth it. Definitely check it out if you have the option. If you decide to mix to analog, I will master the tapes on machines that have custom electronics. (I also maintain a complete machine shop, so there are custom aspects to the tape transport as well, but that's another story...) This equipment can probably extract sound from the tape that surpasses what you heard while mixing.
If you can create and store 24-bit mixes, the comparison with 1/2" is closer. Many people still prefer analog, but 24-bit can also be excellent, with a greater sense of air than DAT, and enough resolution to make even long reverb tails sound convincing. 24-bit storage on inexpensive CDROM discs has a lot of appeal for studios who don't want to buy and maintain an older 1/2" deck. An increasing part of my business arrives in this format. Compare them side by side if you have the chance.
Burning CDRs from computer: Tips & Troubleshooting
This section was published in the March, 2000 issue of EQ Magazine.
Many studios now mix to hard disk, storing the music with 24-bit resolution. They want greater-than-CD quality without proprietary tape formats or bit-splitting, so they burn their hi-res mixes to CDROM as sound files. I often see albums arrive for mastering on two or even four recordable discs.
Everyone looks for ways to save time. When there are two or more discs to make, increasing the the burn speed is tempting, providing that reliability doesn't drop. Over the years, I developed a list of suggestions for creating cleaner burns. This checklist goes from the basic to the more technical, but it might help improve the quality of your final product. Many suggestions came from technical people at companies that produce burners, bus controllers, and disc writing software.
Three main rules: (broken by many - at their own peril)
A note on monitors
Many problems that mastering engineers encounter come from mixdowns made on less than perfect monitors. Its easier to fix the problems when you know that you can trust the monitors. Every engineer needs a reliable reference.
Some prefer smaller nearfield monitors placed close to the listener, since these can minimize problems associated with the acoustics of average rooms. These monitors can't deliver deep bass, but since this is also true for most speakers that consumers use, it's not a bad compromise. Also, speakers in this size range can often create a very accurate stereo image, in depth as well as width.
Some engineers prefer larger wideband monitors, correctly placed in a room that is designed for listening. These systems will give the most accurate picture of the music, assuming the speaker/room match is done right. Of course, most consumers don't have systems this good. Still, there's a lot to be said for speakers that are just plain accurate, regardless of what the rest of the world uses. If your speakers tell the truth, then you can compensate based on experience.
The 1610/1630 Umatic tape
The Umatic (1610/1630) format was the worldwide standard for storing and interchanging CD masters until recently. A strong point of this format is that compared to the common AES/EBU or SPDIF interface that connects most modern audio devices, the SDIF-2 (3-wire) Umatic interface is more stable. Umatic machines offered consistent performance even though the tapes were variable in quality and degraded slightly each time they were played. Sony no longer produces Umatic machines, and I've recently had replicators request that I ship CDR or other formats for long programs, where tape tracking is an issue. This situation was much less common during the heyday of these units. (Not coincidentally, you can buy half a dozen CD drives for the cost of routine maintenance on a single Umatic deck. If I were a replicator running multiple decks, I'd want to phase them out also!)
The net result is that Umatic is becoming less reliable and universal for data interchange. For this reason, after doing over eight hundred albums in Umatic format, I discontinued support of Umatic as of mid 1998.
Fortunately, CDR decks driven at low speeds, from low-jitter sources, are very reliable. Combine this with the ability to audition the actual master that will be used to cut glass, and its not surprising that CDRs have become the standard way of storing 16-bit masters.
My CD has to sound louder than any other disc ever made. Okay?
All kidding aside, this is a concern of record labels whose product is headed for radio play. I've also done a lot of sampler discs, and each artist on a sampler wants their sound to stack up well against the competition. Everyone is looking for an edge, and sheer volume is an obvious way to get that edge. Years ago it was shown that if you play the same piece of music twice for listeners, one time just a bit (1/2 to 3 dB) louder, most folks will prefer the louder playback. Stereo loudspeaker salesmen have used this trick for years to sell "house" speakers that carry the highest profit margin.
If you want maximum level, there is one good reason to go for it at the mastering stage. Like it or not, radio stations will jam your music through their own limiters prior to being transmitted over the airwaves. The sonic quality of these processors is usually not perfect, to say the least. The processors in a good mastering facility will produce high levels and better maintain the sound quality that you have worked so hard to create. I keep highly modified multiband compressors on hand just for this purpose, and the Halo processor also excels in this area. The limiters at the radio station will still be in the signal path, but they won't affect the sound as much.
What are the other considerations? If you master an album super-hot, for airplay only, all the tracks will sound punchy, but you run the risk that people at home will experience listening fatigue after 15 to 30 minutes. Music buffs generally don't enjoy hot sound for more than a little while, even if they like the material itself.
Looking at this problem from a music industry perspective, record labels are getting locked into a no-win contest to be 1/2 dB louder than the next guy. What gets sacrificed is clarity. You can always push the level up a bit, but the live feel and sense of air will suffer. A good home listening system can reproduce over 90dB of dynamic range. This is wasted when the music is crammed into the top 10 dB. Some related information about this can be found in an open letter that I wrote to the editor of an industry magazine on the subject of clipping.
The solution? Its usually possible to settle on a fairly hot compromise level that keeps everyone happy. For those who want to push a particular track very hard, one possible scenario is to release promotional EP's or singles, equalized and compressed for airplay. The record store version can then be mastered for a hi-fi home environment.
Technical tip if radio play is important to your release... be sure to check your mixes in mono as well as stereo. If there are mono compatibility problems, large listening areas may receive a signal that is radically different from the sound you hear in stereo. I pick these problems up quickly when I analyze your tape, but by then its too late. See the section on Creating Tighter Mixes for more info.
To summarize, if you want your whole album as loud as possible, I'll work to make it that way. You just need to be aware of the tradeoffs.
What are the other options for getting my material to sound great?
A handful of top mastering facilities offer engineers with decades of experience plus an intangible: marquis value. Some folks want that Cadillac name to be in their liner notes, and this is not a bad idea - just make sure that the ears that made the facility famous will actually work on your music. Great ears and vast experience command everone's respect, including mine. If marquis value is important, its a good idea to plan six months ahead. Expect album mastering costs to be in the multiple thousands.
At the other end of the scale are small studios that buy software and a CDR drive for their Mac or PC and get into mastering. You can expect rock-bottom rates for transfers from DAT mixdown tapes to CDR. If your multitrack has been mixed carefully, the sweetening and editing needs are basic, and the sound quality meets your standards, then you may get a real bargain.
On the other hand, if the producer decides that the finished CDR needs a little something to make it more competitive or, worse yet, that the software actually pulled some of the life out of the music, then you might need to work with a local facility where mastering is the only business, not a sideline. Many studios can't justify the very high-end toys you need to do the job.
Nevertheless, this option can be a winner if the engineer has great ears, a lot of serious technical and musical experience and top-notch tools. If you have a studio like this near you, please use it. The operator of that facility has paid his dues and deserves your business. You will get a good product and receive great value for your dollar.
Digital editing vs. Crash editing
Before a master CD can be produced, songs need to be put into the correct sequence, and the proper spaces placed between each track. This can be done before sending the tape for sweetening, or I can do it after the music is sweetened.
Digital editing: Most major and indie labels demand that sequencing and spacing be done using a digital editor, for quality reasons. Digital editing allows you to remove countdowns, stick clicks, guitar amp hum and noises between tracks. Fadeins and fadeouts can be "chased" to digital silence so that console or analog tape noise disappears. This gives a polished result that people notice.
Crash editing: Albums can also be sequenced and spaced by "crash editing" - using a digital connection (preferably coaxial, not optical) between two DAT recorders. This method does not allow you to chase the fades, adjust song spacing precisely or remove noise. The target DAT machine should be in record mode for one solid second before hitting PLAY on the playback deck. If you punch in tighter than this, your machine may play it perfectly, but others, including the ones at DRT, may not. Crash edits can produce low-level noises that may become more audible as a result of the mastering process. Crash edits also can insert up to 1 3/4 second delays into the ABS time code that you see on the counter as the tape plays. While this is not audible, it may affect the accuracy with which start IDs can be placed on the master CD. For these reasons I don't offer crash editing as a service.
An open letter to a studio operator: Choices
An experienced mixdown engineer emailed me to ask about mastering his own material and what the specific equipment options might be. My response expands on issues brought up earlier. For what its worth, here it is....
Of course, if you need the best possible sound in the known universe you have to send your tapes to me. I will perform the magic rituals required to make us all wealthy and happy. Life will be good. Barring that........
The TC M-5000 and Weiss units may still be the top of the heap in standalone digital Swiss Army knives. (I was an early M-5000 user.) Many facilities have also been drawn by the low cost of computers. They use EQ and limiter software plugins for ProTools or Sound Forge, such as the L1 Maximizer. Others prefer the features of Sonic Solutions. Studios on a tighter budget often use the TC Finalizer. (Tell it the style, and it masters the music for you! Well, almost.)
Fortunately for people with analog gear that outperforms the digital stuff, converters have improved to 24-bit resolution, and you can make one conversion in and out of either domain without losing the musical feel. It might still cost unreasonably large bucks to make that conversion, but the result is that you can choose digital or analog depending on the sound you need.
If you mix to 1/2" tape and/or prefer the wider palette available in the analog domain, (which I do), there are single band compressors, from the LA2A/3A/Joe Meek optoelectric flavor (slow attack, warm sound), to dozens of all-purpose VCA units (variable attack, neutral sound), to traditional expensive Fairchild/Manley variable-mu tube designs (fairly fast attack, smooth sound). If you're trying to avoid the intermod distortion inherent in all single-band compressors (think low-end mud), Aphex and others make brick wall multiband limiters in the $1K-$2K range. A handful of brands including Sontec, GML, Avalon and Focusrite have pretty much staked out the high end of the analog toy market. They deliver the best performance available from off-the-shelf equipment. Prices run from $2K to $12K per unit for limiters, compressors or EQ. I can't tell you which to buy, since I use different units for different tunes. You need a variety to cover the situations you meet. I tend to buy devices of the type I need, sell the ones that don't make the grade or can't be modified to be useful, and then upgrade the keepers to sound the way I want. I collect and create tools to develop the subtle control that you don't get with a Swiss Army setup. You have to mix colors to get the right tones, then blend them again on the fly as the painting evolves.
Regarding developing an in-house capability: I do albums for studios that have the financial strength and talent to get into mastering. You might ponder two of the reasons why...
1. They don't want to go through the gear evaluation process. Their profit margin comes from their known expertise - session work. The learning curve for mastering - at the quality level they need - can be steep and time consuming. Plus most folks are not fanatic enough to design units from scratch or carve up expensive gear to make it sound the best it can. They need the results without the rest of the nonsense.
2. Conventional wisdom in the high end of the business says to master the music
somewhere other than the mixdown facility. Change the venue - change the perspective -
the music benefits. It takes at least a couple of days away from a project to regain the
perspective you need for mastering. Most engineers I know are well into their next project
by then. The result is that experienced recording clients will send work out for mastering
even if they LOVE your mixes. Its not a question of talent, its about letting specialists
do what they do best. Another facility may actually make your mixes sound better than you
can. On the other hand, if you develop an in-house capability, you can work on material
from other studios, and there's a business opportunity. You know your market and what
makes sense for you. The music business is so large, there's always room for another
person doing quality work.
When to master locally
Experienced mastering engineers offer a perspective based on working with a lot of albums. They can (and should) provide creative input, building on the musical vision of the production team. The result can be a new and different view into the music - an album that sounds "in the pocket".
In working with labels all over the world, I've had success with phone, e-mail, fax and clear written notes to make sure I understand the producer's direction. Still, there have been a few times where the process has not worked. The problem was not that the finished master didn't meet high quality standards, but that the producer's vision was so specific that, in the end, they decided to master it themselves.
Fortunately, we parted friends, but there was a common thread in most of these cases: the producer was also the writer and arranger, and often the principal performer and recording engineer as well. They were so close to the project that it became difficult for them to assign artistic control, even for fine tuning.
This is a fairly rare occurrence, since most music people appreciate the results of a high-quality collaboration. Still, if your vision is extremely precise, you may prefer to work "over the shoulder" of an engineer at a local facility, or even run the controls yourself. You can make the subtle calls on the spot.
You need a great mix to get a great master: Avoiding major surgery
Most people who send albums to DRT have created a competitive product. There are no major technical problems, and the overall level, balance and EQ are in the ballpark. The producer just wants a big, radio-ready sound. At the other extreme, I had one client whose mixes were seriously flawed. After we discussed it, the producer decided to replace some weak tracks and remix the entire album. (You have to admire the commitment!) The mastered CD got chart action in Billboard, so everybody was happy... but the release date had to be pushed back six weeks.
This brings out a key point: mastering can only improve good product. It cannot fix bad mixes, mushy tracks, poor arrangements or sloppy playing. If the kick drum sounds great and the bass guitar is terrible, there will be problems getting both to sound good. If you are at the mixing stage, I welcome you to send an early reference mix for free evaluation. I may hear a problem that you can fix before it spreads across 15 cuts.
Note to musicians: Tradeoffs
Its easy to underestimate what it takes to make a truly fine sounding record. Learning to record music well is like becoming the master of an instrument. Pros need natural talent and a few thousand hours of hard practice, often under the guidance of an expert, to become competent at laying good tracks and mixing. If your group has an aggressive timetable for producing a tight, fully professional CD, you're much better off going to a good studio, rather than buying five to ten thousand worth of recording gear and learning on the fly. You'll get quicker results from someone else's years of experience, heavy investment in gear and excellent room. You can focus on playing and you won't be distracted by technical problems, which can wreck a creative groove quickly.
The flip side of this argument, of course, is that if you have time, dollars and the drive, then making records can provide a lot of long-term satisfaction. Just be realistic about what it takes.
Seven steps in the CD production process.
This is a general overview that describes how CD projects go from start to finish. Details may vary somewhat depending on the replicator you use.
If you need to get advance copies out to agents, labels, or radio stations, I can make short runs of CDRs. Copies are made on the same 8x-certified silver media used for your production master. I can also produce basic single-sided liner note inserts with artist name, album title and track listing - adequate for getting the buzz started about your release, etc. - until your large CD run is ready. If you need retail-ready graphics, I can refer you to sources that provide replication and very sophisticated inserts. You'll need artwork and typesetting if you go this route. The discs themselves can be labeled with indelible markers, circular paper labels, or directly with special color printers.
The Stereo FieldThe stereo field is a both a way of determining how instruments are positioned from left to right, and a way of creating a sense of depth behind the speakers. The two common tools for creating it are the panpot, which positions a sound by controlling it's volume in each channel, and reverb, which creates sense of space. The short delays at the beginning of a reverb signal, called early reflections, create "room sound" and a feeling of size, while the longer reverb tail can simulate a large space and add depth.
Mix BalanceAfter the instruments are positioned, you need the right volume and correct tone for each one. Volume is fairly easy to set. We've all heard well-balanced mixes on CD and radio. If you can clearly hear what an instrument is playing, then the volume setting is close.
The tone part is harder. For discussion, tone can be broken down into two components, spectral content - bass, mids, highs - and attack, the leading edge of a note. On a wide-range instrument, the fundamental tone conveys power, the lower harmonics (midrange) convey sense of fullness or presence, and the higher harmonics, attack and definition. A few examples:
Your Other MonitorsEvery mastering engineer has faced disasters that can be traced back to good people using bad monitors. It's tough to make good decisions if you can't trust what you hear. I would never use loudspeakers costing less than $1000 a pair as my only reference. Everything below that price point (and quite a few above) are pretty severely compromised in some way. To make matters worse, most speakers are not placed in the optimal location in the listening room, which itself contributes more errors. In short, your speakers are lying to you, especially in the bass frequencies. Only the truly massive processing power between your ears is separating the truth from the lies. (Feel better? Didn't think so...)
What's the solution? You could spend next year's mortgage payments on speakers plus room treatment.... Or maybe not... So let's talk headphones! You already have seven pairs in the studio for overdubbing, right? Forget them - we need reference quality. I'll stick my neck out and recommend three fine examples. Sennheiser HD600's, Grado RS2s, or my favorite, Stax Lambda Novas with tube amp. Street price of maybe $330, $450 and $1500 respectively. Ouch! Not cheap, but worth every nickel.
Listen to five minutes of good commercial music on any of them. Then one of your mixes. The differences will be easier to spot with headphones. This is because you have eliminated the room from the equation, and your ears are hearing only direct sound. Plus all of these units are pretty accurate to start with, down into the deep bass where mini-monitors never go. Think of them as near-field monitors on steroids. You'll still need speakers to check panning, since phones exaggerate the stereo image. And phones won't hit you in the chest with your massive new bass tones the way that speakers can. But they can be a magnifying glass for questions of balance and tone. You will hear stuff that was lost through your speakers. And you'll have one more tool for achieving the holy grail - mixes that translate well across many speaker systems. By the way, HD-600s and RS2s have dynamic drivers, so they need a strong, clean driver amp.
Mixing TechniqueIts easy to get overwhelmed when time is short and you have an album to mix. Try slicing the work into manageable chunks:
RecapIf your mixes have a good sense of space, clear instrumental and vocal tones, and energy that builds to a strong finish, the mastering engineer can spend more time building on the strong points, less time fixing problems. The final sound will work on radio, home and car systems, and everyone will be happy. Have at it!
I've had quite a few conversations with artists and owners of smaller studios on ways to improve recordings. Here are a few more tips, expanding on the info in the article above. They might be of interest if you are engineering your own album:
EQ Technique: Using a few channels of sweepable or fully parametric EQ to remove problem frequencies is often more effective than boosting the characteristics you like. Find the offending frequency range by boosting 6 to 12 dB and sweeping back and forth - at fairly narrow bandwidth, if you have the option. Make the sound worse. Then switch from boost to a few dB of cut at the problem frequency. Vary the bandwidth to fine tune. This technique is effective for toning down the inherent resonance in snares, acoustic guitars and other instruments.
A related technique is removing unneeded frequencies, as opposed to objectionable ones. If your mix is sounding denser than you like, try notching out (one track at a time) sections of the musical spectrum above or below the frequencies where a track makes it's major contribution to the mix. The EQ'd result might sound odd when you solo it, but could be the right answer in the context of the whole mix. You will free up 'airspace' needed for other instruments.
Creating Space: When you double track any instrument or vocal, try moving the microphone and the performer within the recording space. Have the backup vocalists step back six inches or switch places for the second pass. Add in a different room mic, etc. Our ears are sensitive to the complex nature of acoustical ambiance. When you provide variation, it comes across as richness. This why having a few different reverbs - even inexpensive ones- is better than having just one, no matter how good the one is.
Kick drum / Bass blend. Half of all problems I correct are related to this, so its worth restating a couple of points from the previous article:
A convincing kick sound has at least two major components, the attack, or beater hit, which lies well above 1000 Hz, and the low-frequency impact, usually located between 40 and 100 Hz. If you don't have the attack component, you get woof, but no definition. Without the lows, you know the kick is there, but it moves no air. The two have to balance. The tuning of the drum, damping, mic technique, and above all, playing create the right combination. Its tempting to add EQ boost below 50Hz to substitute for poor tuning/playing/mic technique etc, but the results are rarely great.
Bass guitar has similar components of string attack and the fundamental tone. If the bass player does not generate enough attack, or you are using a direct feed to the console, another option is to enhance the attack created by the kick drum. This can create the effect of locking the two together more tightly. Again, avoid trying to generate power by boosting ultra-lows. Epic super-low stadium-rock bass tones turn into mush on many systems. The fundamental below 80Hz contributes power, but volume and definition come from the second harmonic. Its not an accident that the classic frequency for bass boost is 100Hz.
Another snare drum note: Many engineers successfully use simple mics like a Shure SM57 on the top of the drum only. You can generate some extra snap with EQ. A muffled, laid back sound generates little excitement. Crisp snare tones take up surprisingly little airspace, but can give the feel of apparent treble boost and energy to the whole mix without sacrificing the warmth of the more legato instruments farther down the midrange. The Halo processor I designed does a great job of handling snare peaks, so don't be afraid to have a strong backbeat.
If you have limiter channels available, try 3 to 6dB on kick and snare as a starting point.
Alternate Mixes: When you have the perfect mix on tape, and all the changes are fresh in your mind, consider creating one or two alternate mixes before moving on to the next track:
The Well Equipped Toolbox. (A.KA.The Bottomless Pit)
The Hired Gun: If you're already equipped, up and running, consider hiring a very experienced tracking and mixing engineer for one day as a consultant. If you have to go into the next state to find the right person, do it. Have a small group set up, rehearsed, and ready to play one or two tunes when the engineer arrives. After you go over the layout, have him/her set up all the mics (close and room), get the sounds and dial in the EQ, effects and compressors. You be the producer for a day! Have them get the sounds you need. Lay tracks and do the mixdown. If the engineer has good communication skills, you will learn more in eight hours than you would in eight weeks on your own. You'll also get useful comments on the quality and efficiency of your setup, based on his wide experience.
I was very fortunate to learn from engineers who worked with well known artists. If you inquire around a bit, you may find talented people who can improve your recording chops quickly. Nowadays there are also excellent magazines available - Mix, EQ, Recording, Electronic Musician, Home Recording, Pro Audio Review come to mind. Studio Sound and AudioMedia are less well known, but excellent. Check them all out - they offer free subscriptions to people in the business.
Much of what I discuss in this presentation relates to technique. Ultimately, mastering has less to do with technique and more with awareness. To produce the best work, you need to be in a space very similar to that of an artist in a live performance. Technique has to be a given. Your instrument has to work quickly, intuitively and without problems. How and when to make the moves should not require thought. The issue is how to express the creative force (Force) that is available to all of us when we work to be receptive. Excellence becomes possible when receptivity combines with experience, constant practice and a quality instrument. Most musicians can relate to this way of working, as well as people familiar with martial arts and similar disciplines. Having all the right factors aligned does not guarantee a great performance, but increases the chances drastically. Even then, an occasional failure is handed to everyone, regardless of skill. (In mastering, that's a client who can't be satisfied.) Hopefully we learn and acquire some humility.
To the Almighty, Who protects us at every step, and Who taught me through the following
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