Earlier this year, we launched Audio Analysis — a web tool that gives ACX Producers instant feedback on their production audio files, allowing them to identify and correct technical issues before submitting their projects for review. Audio Analysis improves the workflow for Producers during a production, but we want all ACX Producers to feel confident about their sound before they even submit their first audition, so we created Audio Lab. Simply upload your audio files and Audio Lab gives you immediate feedback on how they measure up to our Audio Submission Requirements on seven important metrics, including peak value and RMS. We’re excited about the potential this tool offers for new and seasoned Producers alike, so we thought we’d break down how you can use Audio Lab effectively to hone your sound like a pro.
Who can use Audio Lab?
Audio Lab is open to any ACX user – if you have an account with ACX, you can upload files for analysis on Audio Lab. New producers can create an ACX account and start using it to test their sound progress as they learn to gauge when they’re ready to start auditioning. Seasoned producers can use it to test and calibrate new gear to meet our submission requirements.
How do I use it?
It’s easy! Just upload your audio files to the Audio Lab page – you can find it under the “Production Resources” tab on ACX – and the system will give you immediate feedback on how your files measure up to our submission requirements on RMS, peak value, bitrate, bitrate method, and sample rate. The results are only visible to you.
What sort of files should I use?
Audio Lab is built to analyze any spoken word MP3 audio files, but we recommend uploading files that you’ve recorded, edited, and mastered to our submission requirements as you would if you were producing an audiobook, even if you’re just reading test passages from a favorite book. This will give you the best sense of how production-ready your sound is, and will let you know what you need to adjust to pass QA.
When do I use it?
Anytime you have audio you want to test! Here are just a few times you might find it useful:
Use it to test samples for your profile when you first join ACX
Use it to make sure you’re ready to take on audiobook projects
Before auditioning for a specific project
When you’re mid-project, to test your audio before sending it to the Rights Holder for approval
Whenever you change your equipment or studio space
Why should I use it?
Periodically testing your files with Audio Lab – whether you’re a new narrator or an ACX veteran – ensures you enter into every contract with the confidence that you can deliver a great production.
We hope that Audio Lab offers the Producer community the resources you need to craft awesome productions. If you’re new to ACX or to audiobook production in general, and you’re looking for more resources to help you narrate, record, produce, and distribute great sounding audiobooks, be sure to browse this blog for more tips, visit our YouTube channel, and check out our Audio Terminology Glossary to get up to speed.
Today’s lesson is going to be a little different from my others. Since I’m lucky enough to have such eager students, I often get questions about one of the more mystifying aspects of audiobook production: mastering. Today, I’ll answer the most common questions and give you a breakdown of the basics steps of the mastering process. But first, let’s review ACX’s Audio Submission Requirements:
Now that we’ve covered the basics, let’s get to those questions.
Q: Why do I need to master my audiobook productions?
A: Mastering is the the final step of post-production and the glue that brings the entire audiobook together. All chapters/sections are brought up to matching levels, which provides a smooth listening experience. Additionally, removing unwanted high and low frequencies can help reduce any hum or hiss that may be in a recording.
Q: Why do I need to follow all of these mastering requirements?
A: Audible offers each audiobook in a range of different audio formats to accommodate listeners on Audible, Amazon, and iTunes. This means that audio quality will range from very high fidelity to lesser fidelities that equate to smaller file sizes and quicker downloads. Basically, if your RMS is between -18dB and -23dB RMS, with peaks at -3dB, you’ll achieve the optimal sound across all formats.
Q: What is RMS?
A: RMS has many functions, but for audiobooks it’s the value assigned to the overall volume level of an audio file. Audible will apply light dynamics processing once your audiobooks are submitted, so your production’s overall levels should not be too high or too low. For example, a production with a low RMS but loud peaks could end up with technical issues within the file, such as uneven narration levels, a high noise floor, etc.
Q: What is peaking?
Examples of peaks in an audiobook recording.
A: Peaks are the loudest part or parts of an audio file. If the script calls for a change from calm to excited, or from speaking to yelling, those excited or loud parts will most likely have the highest peaks. Our Audio Submission Requirements call for peaks to be under -3dB, which helps prevent distortion. If you have any 0dB peaks after mastering, you’ll need to adjust your limiter or normalizer settings and try again on your edited audio. If you have 0dB peaks before mastering, you’ll need to find out whether those peaks occurred during recording or after. If it happened during recording, you’ll need to lower your pre-amp’s level and re-record those lines of narration.
Q: What is an EQ?
A: An EQ (short for “equalizer”) is a tool that allows you to adjust the level of any frequency in an audio file. The typical frequency range that the human ear can detect is 20Hz to 20,000 kHz. The lower frequencies in this range are the bass/low range, while the middle is the mid-range, and high frequencies are the high range. Most EQ plug-ins will have high pass filter and a low pass filter. Using the high pass will remove any unwanted bass (low) frequencies that could have occurred during recording, such as the hum of your computer. A low pass will remove high frequency noises in your audio, like an air conditioner or microphone hiss. I strongly recommend applying EQ before you master, as unwanted high or low frequencies can have an impact on the next step in your mastering process – applying a limiter. Removing a low frequency hum allows the limiter to more easily adjust to the narration at hand.
Q: What is a limiter?
A: A limiter is a dynamics processor. Applying a limiter lowers any high peaks in your audio, which allows the volume of the narration to be more even throughout. This lets you bring up the overall volume of your audio, which may be necessary to meet ACX’s RMS requirement (-18dB RMS to -23dB RMS). For example, if your max peak level is -4dB but your overall RMS level is -27dB RMS, your audio will look similar to the image below:
(Click images to expand)
In this case, you can use a limiter to lower all peaks by -3dB. Your max peak level would now be -7dB, as illustrated below.
Since ACX’s peaks requirement is -3dB, you can now raise the overall level of the audio by +4dB. That would bring your RMS to -23dB RMS, which is within our required range. Your mastered audio would then look something like this:
Now that we’ve gone over mastering as a concept, I think you’re ready to take a look at my Mastering Breakdown. It’s a great checklist to mark off each time you master an audiobook.
ALEX’S MASTERING BREAKDOWN
Assess all audio files to ensure no peaks or clipping exist in the audio.
A good recording and careful editing are both necessary to achieve this.
Group all similar files together during the assessment so they can be processed at the same time.
Apply your “Mastering Chain” byusing the following processes, in order:
Remove all unnecessary low and high frequencies by applying EQ to clean up the sound of your recordings and provide more headroom in order to boost your files levels effectively. This is a great way to minimize hum and hiss in an otherwise good recording!
Bring all files up to the proper dynamic levels as specified by the ACX Audio Submission Requirements page by using normalization, compression and/or limiting, and, if necessary, a final volume adjustment.
Listen to your audio after mastering to ensure the operation did not over-process or under-process the recordings. If the resultant audio is at one consistent volume with no change in dynamic level, you’ve likely over- If your audio has sudden spikes and drop offs (indicating it is too dynamic), you’ve under-processed.
That wraps up today’s lesson. I hope you all have a stronger understanding of audiobook mastering than when we started. Mastering your productions can seem daunting and technical, but once you know which aspects of your voice and recording space need to be accounted for, you’ll be able to apply the same processes over and over again with minimal changes. You’ll take your audiobook productions from good to great, and your listeners will appreciate the subtle improvements in sound quality you’ve achieved.
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We’d like to introduce you to the newest member of the ACX team, Alex the Audio Scientist. Alex has a degree in Audiobook Studies from ACX University, and he’ll be stopping by the blog from time to time to explain some key aspects of audiobook recording and production. So without further ado, take it away Alex!
Nice to Meet You!
Hi everyone I’m excited to share my knowledge of all things audiobooks and help you improve your ACX productions. Before today’s lesson, I hope you’ve read previous posts on this blog regarding home studio setup, because today I’ll cover a common problem with voice recording spaces: a high noise floor. Enjoy the video below, and take good notes – there’ll be a quiz afterward!
And we’re back. Ready for that quiz I mentioned? Let’s see how much you learned. Leave your answers in the comments below. The first person to get every answer correct will get a shout out in my next post!
The noise floor is the ________ level of background noise in a recording, when no narration is taking place.
A high noise floor in a home studio can be caused by ________, ________, ________, ________, or ________.
Its best to address your noise floor issues during the ________ stage.
I recommended using a ________ to remove unwanted frequencies, such as a low rumble.
The appropriate frequency range to target the removal of this low rumble is usually between ________ and ________ Hz.
The ACX Audio Submission Requirements call for a noise floor no higher than ________ dB RMS.
Welcome back to the second half of my two-part home studio setup series. Last week I covered where to place your home studio, how to properly soundproof it, and the basic equipment you’ll use in it. Today, I’d like to share real-world examples from three Audible Approved Producers. Let’s look at (and listen to) the great results a home studio can produce.
Visible Sound Audiobooks
The controlling and deadening of acoustic reflections in her bedroom and specifically around the microphone is one of the main contributing factors to the professional audio quality of her recordings – Ben Glawe of Visible Sound Audiobooks.
This home studio photo comes to us from Visible Sound Audiobooks, an Audible-Approved Producer whose operations primarily take place in a Brooklyn bedroom. How does this team achieve their professional sound quality in the midst of the country’s busiest city? House-narrator Christine Papania explains:
The biggest noise problem with my bedroom was my window, which overlooks a a noisy street in Brooklyn as well as a park. I bought special blackout curtains which block out light and sound from windows, which lowered the outside noise to acceptable levels. My laptop fan was also leaking noise into the microphone, but the addition of a silent laptop cooling pad fixed the problem.
Now we’ll hear a recording from Visible Sound’s space. You might be surprised how good it sounds!
kate udall
Kate Udall got her start as a narrator at Audible Studios. After working on her production chops and securing some great ACX titles, she earned herself the Audible-Approved Producer distinction. Kate’s studio is a great representation of an effective DIY home recording setup.
According to Kate
We call it Fuzzy Jail around here. It is made of blankets, the size of a cell and I am often inside in locked-down solitary confinement.
Kate uses thick packing blankets to isolate her recording studio from the rest of the room’s noises, which also provides the added benefit of reducing sound reflections that may otherwise occur on the side wall to the left. Her microphone is situated in front of an Auralex Mudguard, a great tool that can further reduce sonic clutter that occurs in home recording environments. She is also wise to set up an external monitor and other necessary components so that her laptop, which sits outside of the recording environment, does not introduce more artifacts and noises into the recorded signal.
Lets listen to a recording from Kate’s Studio:
Stephen Bel Davies
Our final example shows the upper limits are of home audiobook production. Yes, you are looking at a home studio! This photo comes to us from veteran narrator Stephen Bel Davies.
Located in his Manhattan bedroom, this Studiobricks* installation is the top-of-the-line option for home recording due to its incredible noise-blocking capabilities and reflection controlled environment. Acoustic treatments on all walls, as well as the ceiling, guarantees a deadened recording space with extremely dampened artifacts and reflections. While Stephen is able to achieve a stunning -60dB of sound reduction with this setup, it doesn’t come cheap. These installations will set you back about at least $4,000 before factoring in installation costs. Still – one can dream!
Here is a bit of audio produced in Stephen’s studio.
FINAL NOTES
While Whisper Rooms are an ideal recording environment for any audiobook narrator, they are not necessary to produce a great recording. The most important consideration during an ACX production is consistency – both in practice and in aesthetic. For this reason, after you’ve installed your home studio, I strongly encourage you to read up on my four-part series, How to Succeed at Audiobook Production, which goes over methodologies to ensure success with your new audio production system.
How do you achieve a professional recording? Leave your feedback in the comments below.
(This section originally misidentified Mr. Bel Davies home studio as a WhisperRoom.)
Welcome to the latest musings from Andrew the Audio Scientist. Today, I’ll be addressing the most essential component of a successful ACX audiobook production: constructing a home recording studio. You may be surprised to find how clean and clear your narration can sound after implementing just a few of the techniques and products below into your own studio setup. Let’s take a look at the two main aspects of a solid studio arrangement.
The Room
The most important consideration when building your home studio is its location. The ideal recording space dimensions are rectangular (NOT square), with low ceilings and 90º corners. Closets and other enclosed spaces make perfectly great recording spaces after implementing a few basic room treatments.
Reflection absorption materials, such as the ones detailed on the ACX Beginners Amazon Wish List can make all the difference. The primary reflection points that should be addressed are any surfaces behind the microphone and on the side walls, at a distance exactly half-way between your sitting position and the microphone stand. If you want to go the DIY route, the same effect can be achieved by hanging your old winter coats on the walls, or even throwing up moving blankets where clothing is not an option. The idea is to use fabrics that are thick and provide ample absorption so that once sound hits the material, it stops dead in its tracks.
Isolation is an important consideration for your room, too. An important step in the audiobook production process is the pasting of clean room tone on top of edits and other extraneous noises. Doing so can be greatly inhibited, though, by a non-ideal recording space. You may find the room tone to be too noisy to affect any real sonic improvements. To combat this and other noise problems, make sure to isolate outside noises from your recording space by hanging blackout curtains at all windows, and insulating your room’s open cracks and crevices. However, note that there are some rooms where even the most expensive room treatments are unlikely to make a big impact.
ACX Recommends:
Avoid installing your studio in large rooms such as kitchens and sun rooms. These will cause undesirable echo and reverberation, and result in a muddy sound.
Small rooms with reflective surfaces like bathrooms should also be avoided, because the porcelain and mirrors will send your voice flying across the room without remorse.
Last but not least, recording outdoors is a big no-no. While the sounds of nature can be pleasant, squawking birds and passing cars are not sounds that belong in audiobook productions.
THE MICROPHONE
This is pretty obvious – if you want to record your voice at home, you’ll need a microphone. Not so obvious, however, is the kind of microphone you need to purchase. At ACX, we recommend a large-diaphragm cardioid condenser microphone. These microphones are typically more accurate and clean than other types of vocal microphones, but are also more sensitive to recording mistakes. You’ll need to adhere to some setup best practices to get the most out of your purchase:
Placement – A microphone is best set up at a point no further than 40% away from the front wall. Ideally, the microphone would be placed half-way between the side walls.
Height – Microphones placed at or below mouth-level tend to pick up more “body” of a voice, while placement above the mouth (closer to the nasal cavity) capture a more “bright” and airy sound. However, this is a very personal aspect to studio configuration that is best left to experimentation.
Diagram of a ideal mic placement within a home studio
Distance – It is never necessary to stand the microphone further than 6-10 inches from your mouth. This should help you avoid plosives, but we strongly recommend purchasing a pop filter for your microphone if it does not already come with one. (For you DIYers, you can also construct your own pop filter out of – no joke – some pantyhose and flex tubing, as demonstrated in this Lifehacker article)
Interface – All cardioid condenser microphones require an audio interface that can provide phantom power to the microphone. If phantom power is not provided to the microphone, then it will not work.
ACX Recommends:
One of our favorite starter microphones of this type is the Rode NT1-A, which can be found on the ACX Beginners Amazon Wish List. The NT1-A kit available on Amazon comes with a pop filter and all of the mounting hardware needed to get started. This, in conjunction with the Blue Icicle XLR-to-USB microphone interface and a solid microphone stand, provides an excellent starter ACX production system.
Following these basic rules for home studio setup will allow you to transform the appropriate area of your living space into a great sounding vocal booth. Check out Part 2 to see and hear examples of some real-life Audible Approved Producers home studios.
Welcome back to How to Succeed at Audiobook Production. If you’ve been following this series, then you’ve read up on The ACX Mile, which helps you perfect the art of narration recording, perform a complete edit and QC your recorded audio, and learn audio mastering best practices. If you haven’t perused these posts, I recommend doing so before continuing on.
Now that you’re caught up, let’s move on to the fourth and final part of my series: encoding and file delivery.
Rounding The Final Corner
Upon a successful master, your audiobook production is not quite finished. Keeping that in mind, watch the final video in our series, and review the key points I discuss after.
The Home Stretch
I recommend you perform another final QC pass on your audio before moving on to encoding and delivering your audio. After putting so much effort into your production, the last thing we want to do is send an audio review notice to fix missing chapters or out-of-order audio files. The post-mastering QC pass needn’t be as in-depth as what I recommend in the article on editing; it could be as simple as verifying the volume levels are meet our specifications, that the content is complete, and that the audio files are numbered and named in the proper order.
If everything looks ready, then we can begin the encoding process. I cover this in more detail in my post, Encoding Audio with Andrew the Audio Scientist, but I’ll summarize here. That post contains a link to our instructions detailing how to encode your audiobook to ACX specifications using the free and cross-platform fre:ac encoding software.
Also be cognizant of ACX’s file-level requirements. The encoding options you choose can potentially cause the run-time or the file size to go over our specifications. Each file must contain a single chapter with a length no longer than 120 minutes..
Crossing the Finish Line
Once you verify your audio complies with our MP3 encoding and file-level requirements, you’re ready to upload our audio to the ACX production manager! Here are some last-minute tips that could potentially save you from an audio review notice.
1. Be smart about your sample. The retail sample you provide will likely be a customer’s first glimpse into your work, so make this moment count! I recommend grabbing the audio from an early point in the book, so you don’t give away plot developments. Also, be mindful of the ACX sample requirements, which expressly prohibit erotic/mature content. If your book is on the wilder side, find a section that is appropriate for all audiences.
2. Double-check your book’s chapter order when uploading your files. Files arrive to ACX in the same order as they are uploaded to the Production Manager. Doing this last check will make the QA process simpler and faster, allowing us to get your title on sale more quickly.
3. Ensure your file names are clear and concise. To help ACX best understand your audio, I recommend naming your audio using a template such as:
Since we are at the end of the How to Succeed at Audiobook Production series (but not the end of my regular contributions to the blog), I want to take this opportunity to thank our users, subscribers and readers for your loyal viewership.
But don’t worry, I’ll be back with more audiobook production tips soon. In the meantime, share your own with your fellow readers in the comments below!
Andrew the Audio Scientist here, and today I’m presenting part three of my How to Succeed at Audiobook Production series. Let’s dig into one of the most important, yet least understood aspects of audiobook production: Mastering. But before we tackle that, make sure you’ve done proper editing and QC passes on your raw audio. Check out last week’s post for more on those important steps, and read on for my advice on audiobook mastering.
Mastering the Art of Mastering
Before we get to the video below, I want to remind you of the key to producing reliably great sounding audiobooks, especially in the mastering stage: consistency.
Mastering is, in essence, the process of bringing your files closer to one another in terms of sound quality and dynamic range, so the listener will enjoy a book which sounds the same all the way through.
The most important thing to remember about mastering is that it is done not to make a poor recording sound good, but rather to make a good recording sound great. Mastering, like editing, is a key aspect of the perceived professionalism of your production. While the average customer is not thinking about the mastering of a title while listening, the boost of clarity and consistency your narration receives from a proper master cannot be ignored. So, while the process of mastering an audiobook may appear cryptic at first, it is essential to achieving an optimal sound quality for your production.
Now, let’s watch part three of How to Succeed at Audiobook Production, and after, review the mastering tips I suggest below.
Mastering Breakdown
Audiobook mastering involves a few major steps:
Assess all audio files to ensure no peaks or clipping exist in the audio. A good recording and careful editing are both necessary to achieve this.
Group all similar files together during the assessment so they can be processed at the same time.
Bring each group of audio files into your DAW, and perform the following processes in the following order (this is referred to as your “mastering chain”):
Remove all unnecessary low and high frequencies to clean up the sound of your recordings and provide more headroom in order to boost your files levels effectively. This is a great way to minimize hum and hiss in an otherwise good recording!
Bring all files up to the proper dynamic levels as specified by the ACX Audio Submission Requirements page by using normalization, compression and/or limiting, and, if necessary, a final volume adjustment.
Check the audio after mastering to ensure the operation did not over-process or under-process the recordings.
A common mastering chain for an ACX production is as follows:
Equalization/filtering
Remove low (80hz and lower) and high (16kHz and higher) frequencies by using a high-pass and low-pass filter, respectively. Set the high-pass filter to remove sounds below 80hz, and set the low-pass filter to remove sounds above 16kHz. If available, set the Q to the highest-possible setting for both filters. Usually, that setting is 24dB or 48dB per octave.
Normalization
Typically, you should normalize your peaks to -6dB.
Compression/Limiting
We recommend using a limiter, if available, instead of a compressor. Compression can achieve similar results, but it may also decrease the dynamic range of your vocal recording if used improperly. To properly utilize limiting on your files, start by setting your limiter’s maximum output to -3dB. Then, turn up the gain on your limiter until you have achieved a loud, clear, and consistent sound. Don’t boost the level too high. Otherwise, you may distort your voice, or bring up the noise floor of your recording too much. Remember: the better your recording and editing, the easier this process will be! If you have not yet read the first and second parts of this blog post series, I strongly recommend you do so. It can greatly reduce the workload involved in mastering your audiobook.
Tips for Each Step of the Mastering Process
Before you begin mastering, record and edit the entire audiobook to completion. Then, make a final “completed edits backup,” – which I refer to in my prior blog post on file management – of each chapter. Maintaining a backup file is imperative, in case you discover any issues with the audio while mastering.
A good recording is everything. Prior to mastering, a well-recorded audio file will have an RMS value no greater than -28dB RMS and peaks at a level no higher than -12 dB This provides the headroom needed to boost the volume of your production without needing to compress the signal heavily. If your peaks are already nearing -3dB before mastering, make sure no loud noises remain in the audio. If no erroneous sounds are found, then it’s likely you recorded too loudly. This is why learning how to properly prepare for and record your narration is essential to performing a successful master.
Plugins cannot help an inconsistent or noisy recording. Some people attempt to fix deficiencies in their recordings or their editing by using noise reduction plugins and gates. Software like this can be effective if used properly, but more often than not, the use of such plugins will cause more harm than good on an audiobook production. I strongly recommended you take the time to focus on your recording environment, as well as your recording and editing techniques, so you do not need to resort to the use of such software. It will save you valuable time as well as money – those plugins can get expensive!
In order to group your audio files together effectively, leverage the audio measurement tools available in your DAW to find the audio files that are similar to one another. If you are an Audacity user, the “stats.ny” plugin will be essential to performing this task. See this thread from the Audacity forums for installation and use instructions.
Most DAWs have a similar capability, so if you are not aware of what tools can be used to achieve these actions in your particular software, contact the manufacturer to receive assistance in their use.
Double-check your masters. Use the same function on your DAW that you used to group your pre-mastered files in order to check your new mastered files. If your audio measurements fall within the ACX Audio Submission Requirements, you should be good to go, which brings us to our final step.
Verify the following ACX Audio Submission Requirements. Are all of your files’ peaks hitting around -3dB? Is each file’s average RMS between -18 and -23dB RMS? How audible is your noise floor at normal listening levels? There’s no shame in attempting a second master if you’ve found flaws in your new mastered files – that’s why you saved your Completed Edits Backup files after you completed your edits.
In truth, the most important mastering tip I can impart upon you, is to try, try again until you get it right! Mastering is very much a process of trial and error until you learn the tips and tricks that suit your production environment. Once you find settings for your mastering chain that work well for your voice and recording space, remember to save the configurations as presets so that you can easily reference them for your next ACX title. If you’ve established a consistent workflow for the recording and editing stages of audiobook production, then your mastering workflow will be a piece of cake!
Do you have mastering tips that Andrew didn’t cover here? Share them in the comments below, and join us next week for the fourth and final part of Andrew’s series: encoding and file delivery.
Greetings! Andrew the Audio Scientist here, back with more advice for ACX producers. Today, I present the second part in my four-week video series, How to Succeed at Audiobook Production. Last week, I introduced The ACX Mile and covered best practices for the preparation and recording of your audiobook productions. This week, I’ll address editing your raw audiobook recordings.
Editing and QC
Before we get to the video below, I want to remind you of the key to producing reliably great sounding audiobooks: consistency. Establishing a routine you can return to time and again will set you up for success in the later stages of your productions and result in high quality final audio.
Editing an audiobook can be as demanding a task as recording one, but optimizing your editing practices can greatly reduce the workload. Let’s watch part two of How to Succeed at Audiobook Production, and after, review the editing tips I suggest below.
Editing Breakdown
Audiobook editing is broken down into two phases: an audio editing stage, followed by a QC stage.
Audio editing involves:
Removal of extraneous and distracting noises from the audio.
Modifying the pacing of the narration.
Dividing the chapters into individual files, and preparing their heads and tails to ACX’s Audio Submission Requirements.
Noting errors which may necessitate a re-record.
The QC involves:
Listening through the entire audiobook again to confirm the quality of the narration and the completion of the content.
Marking and verifying all errors identified as necessitating a re-record
Creating a QC packet to organize all errors.
Re-recording the phrases needing improvement and placing these new recordings into the edited audio.
Basic Editing Tips for Successful Audiobook Production
Mark your audio files – While recording narration, I recommend you place a marker at the beginning of each section or chapter of your audiobook in your DAW. This is helpful in verifying the completion of the recordings, and also gives an excellent point of reference to use in the QC stage of the editing process. While editing, place markers at all errors you’ve identified as requiring a re-record of the phrase/section in question. This makes the QC stage much easier. Click here for a sample QC sheet to help you note errors in your recording.
Always use headphones – Editing spoken word audio requires a good pair of headphones. In last week’s post, I alluded to the fact that most audiobook productions only contain two sounds: your voice, and your recording space. Pesky clicks, chair squeaks, and other external noises are more easily heard in audiobooks because they have nowhere to hide. These sounds can limit the listener’s immersion into the story, and thus diminish the listening experience. Luckily, professional headphones are more affordable than ever before. Check out the entry on headphones in the ACX Studio Gear series for recommendations.
Clean room tone is a must – Replacing gaps of silence with room tone is essential to a well-produced audiobook. Depending on your narration style and editing technique, you may also want to use room tone to modify the pacing of your read – an effective means of improving the clarity of your narration without needing to re-record the passage. However, if the room tone you’re using to perform this task contains noise of its own, then the entire editing process would be for naught. Be sure to listen back to your room tone at a high volume before editing it into your production to ensure it is sufficiently quiet.
Don’t be afraid to crank the volume – Because you have not mastered your audiobook yet, the dynamic range of your recording may require you to ride the volume of your headphone output. This is OK! You want to ensure every portion of audio is clear enough to discern the clicks and extraneous noises that are contained within the recording. Mastering will bring up the volume of your recording substantially, including all sounds not caught during the edit stage. If they aren’t removed at this stage of the production process, those noises will present significant difficulties later on.
Be mindful of your time – Experienced audiobook editors spend roughly three hours editing every hour of raw recorded audio. In addition, the QC process involves listening back to the entire book a second time. This equates to roughly 4 hours of work per hour of un-edited audio. If you are breezing through edits at a much quicker pace, then you may want to give your audio a second pass. Audiobooks are lengthy productions, so it’s in your production’s best interests to be thorough. On the other hand, if you find yourself obsessing with one issue, you may want to mark it and come back to it later. People have a tendency to be harder on themselves when they’re editing their own voice recordings, so it may be best to take a step back from the issue for a while and revisit it later. In any event, if you find yourself spending more than a minute on one issue with your audio, it may be best to simply re-record the line instead.
Read part 3, which covers audiobook mastering, here.
Welcome to another installation of Andrew the Audio Scientist’s insights on audiobook production! Today, I present the first part in my four-week video series, How to Succeed at Audiobook Production. Week 1 addresses the preparation and recording of a new ACX title. Coming up, we’ll cover editing, mastering, and delivering your audiobook productions.
Achieving Consistency in Audiobook Production
Ask any member of the ACX Quality Assurance team what the most important aspect of audiobook production is, and they’ll all give the same answer: consistency. Your time on ACX should be spent acquiring new acting gigs, not tinkering with the technical details of last-minute production issues. To help you achieve consistency and avoid pesky technical problems that could threaten the success of your productions, I’d like to share with you my presentation from the 2014 Narrator Knowledge Exchange, which details a new concept I’ve dubbed “The ACX Mile.”
The ACX Mile
To better understand the need for methodological production, I have broken down audiobook production into a comprehensible four-step procedure, which I lovingly refer to as The ACX Mile. When running a race on a track, a runner may not begin a new lap until he or she has fully completed the current lap. Consider the audiobook production process as a four-lap race, with an appropriate warm-up period preceding it:
Warm Up: Script and Studio Preparation
Lap One: Recording
Lap Two: Editing and QC
Lap Three: Mastering
Lap Four: Encoding and Delivery
Now, watch part one of How to Succeed at Audiobook Production, and after, review the pre-production and recording tips I address in the video.
Basic Recording Tips for Successful Audiobook Production
Draft a production schedule – An experienced ACX producer will spend roughly six hours in production for every hour of completed audio. This means , for a five hour title, an ACX producer should anticipate spending at least 30 hours on the successful production and completion of their title.
Perform a thorough script prep – Before recording, ensure you’ve read, notated, and fully understood every line of your title. Audiobooks are all about using your voice to tell your Rights Holder’s story, so fidelity to the title is a necessity. Send questions unanswered by your script prep to your Rights Holder, and don’t be afraid to do some research. Sites like AudioEloquence.com are great for determining the accepted pronunciations of foreign, historical, and other uncommon words.
Log your optimal settings – Once you’ve obtained a good microphone gain on your audio interface and positioned your microphone perfectly, mark the area with electrical tape so you have a reference. This way, on the following day of recording, you’ll be able to set your position and settings to the exact same positions as before.
Verify your room tone before recording – After setting your record levels, ensure you have recorded 30 seconds of clean room tone to analyze. Listen back to your recording with headphones, ensuring no undesirable sounds are contained within. If the sound is clean and quiet, you should be ready to record.
Back up your raw audio – If you have not established a file backup technique, see my previous post on File Management.
Noise reduction plugins can’t fix a bad recording – Utilizing plugins, such as noise and click reduction, is strongly discouraged. The improper use of such software may introduce new artifacts and undesirable sounds into your audiobook, and they are rarely effective at addressing the noise concerns of audiobooks.
If the room in which you’re recording is just too noisy, even after isolating your space, putting up acoustic panels to deaden reflections, and utilizing an in-line high-pass filter to reduce rumble and hum, it’s likely your recording space is not located in an ideal setting. The best solution may be to simply install your recording studio elsewhere. Such a step may seem drastic, but nothing is more important to a successful audiobook production than a great initial record.
It is important to keep in mind that, like a marathon, The ACX Mile is best run slow-and-steady. Very few audio errors can truly be “fixed in post,” so it is best to start off on the right foot, even if that makes the actual work a little more time-consuming. I suggest making an ideal and permanent recording setup a top priority. Luckily for you, great audiobooks consist of only two components: your narration, and the recording space. Get that step of the production process down pat, and the rest will come with a little perseverance and healthy amount of impassioned storytelling.
Read part 2, which covers audiobook editing and QC, here.
ACX’s resident audio scientist first joined us on the blog last month, when he discussed the theory and best practices for encoding audio. Today, he’s back to discuss the bedrock of any successful audiobook production: file management.
File Backup and Preservation
Anybody who has produced a lengthy audiobook will tell you that it can be rather arduous. After hours of prep work, days of recording your narration, and several additional days of editing, QC and mastering, the last thing you want to have happen is a disastrous and sudden loss of all your hard work.
As a former Audible Studios engineer and digital expert witness, it didn’t take long for me to realize the importance of backing up my work. While it may be obvious to some producers that data backup is important, learning file storage and archiving methods appropriate for audiobooks is key to your project’s success. Today, I’d like to go over some best practices i have found from my reasearch on sites like https://www.flashbackdata.com/data-recovery/server-raid-recovery/ for data preservation and how you can help prevent any tragic file loss for your next ACX production.
5 Keys to Proper File Management
SAVE, SAVE, SAVE. Make a habit of saving your work every five minutes. It takes almost no time at all and will ensure that, if data loss occurs, you will be able to recover most of your current work. The keyboard shortcut to save is almost always “Ctrl+S” in a Windows program, and “Command+S” in a Mac program (command is the “⌘” key on your Mac keyboard).
Each chapter’s audio file should be backed up upon completion of each stage of production:
Completed Recording Backup – The WAV or AIFF file containing the completed raw recording of your chapter.
Completed Edits Backup – The WAV or AIFF file containing the completed edits to your recorded audio.
Mastered Audio Backup – The WAV or AIFF audio file created after putting the Completed Edits Backup file through your mastering chain.
Encoded Masters – The Mastered Audio Backup file that has been encoded to MP3 for ACX submission. This is your final, retail-ready audio.
At the end of each day of production, you should make a backup of your DAW session, making sure the filename contains the day’s date.
Each time you make a backup of your work, it is strongly recommended that you store the files in two storage locations. (We recommend doing automatic backups to an external hard drive as well as cloud storage. More on that in a bit!)
Until you are ready to encode and submit your audio to ACX, back up all audio as WAV or AIFF files. No chapter file should be backed up as an MP3 unless it is 100% complete and ready for ACX submission. Making changes directly to an MP3 will lower the audio quality of your final production.
The above practices are important habits to form. Should you ever need to make changes to your files or fix an error found by our audio QA team, having consistent backups at each stage of your production will ensure that changes can be easily committed. For instance, if you master a chapter file only to discover that you want to re-record a particular line of dialog, doing so would be as easy as opening up your chapter’s Completed Edits Backup file and re-recording the line. Without this file, you will be forced to record and master your new dialog to a different file and paste it on top of your old Mastered Audio Backup file. Things can get messy!
Data Storage Options
File preservation is important, but it is undoubtedly a hassle. Luckily, file storage is more versatile, cheap, and reliable than ever before. We producers can take advantage of not just excellent portable hard drives, but specialized software and online backup services as well! We recommend the options below.
Portable External Hard Drive – The easiest and quickest file storage solution is to simply purchase an external hard drive. We love the Seagate Expansion drive series, which has a 1TB option priced at only $64.99. Cheap and easy to use, these drives should be on the shopping list of every beginning ACX producer. However, using it can be a bit clunky, as you must organize all of your files manually.
Backup Scheduling Software – Luckily, there exists software for both Windows and Macintosh platforms that aid file backup. We strongly recommend that Mac users utilize the built-in Time Machine feature on OSX to automatically back up and organize your files on your external hard drive. For Windows, I love the free FBackup by Softland. Both of these tools are easy to use and can be configured to automatically back up your files to external locations every night, or even every time the file is modified.
Cloud Storage – Amazon, ACX’s parent company, knows as well as anyone how important reliable storage solutions are for consumers. AWS, Amazon’s online web storage platform, is the leading “cloud storage” solution on the web. What is cloud storage exactly? In essence, it is a series of interconnected servers which safely handle and store massive amounts of data for customers of all stripes. Amazon provides this service to consumers for free as Amazon Cloud Drive. Upon signing up, all users receive 5GB of free storage! Using Amazon Cloud Drive in conjunction with the free Cloud Drive App, you can automatically back up your files to the Amazon Cloud Drive network without needing to lift a finger. Once you finish installing the Cloud Drive App, simply follow the on-screen instructions to set up your computer for automatic nightly backups.
In following these best-practices, you may save yourself and your rights holder from a potential disaster, and you will be putting your best foot forward by amply protecting both your hard work and your rights holder’s intellectual property.
What is your file management and backup process? Do you use any of the methods Andrew recommends above?
come back to the second half of my two-part home studio setup series. 
Audiobook Creation Exchange Blog (ACX) 