frequently asked questions

Production Parts

Additional Parts for Production (Additional charges apply)
DDP for CD Production
Mastered for iTunes Specific Versions
HD Masters (24 bit files)

Vinyl Lacquers

Vinyl Specific Hi-Res Cutting Files

Other Mastering Deliverables (Additional charges apply)
Mastered Alt Mixes: Instrumentals, Acapellas, TV tracks


Mastered for iTunes Versions

Mastered for iTunes(sometimes shortened to MFiT) is a process developed by Apple that mastering engineers follow in order to submit the highest quality master to Apple for sale through iTunes.

In order to be MFiT certified the client must provide a high resolution master to us for the mastering session. The master must be at least 24-bits, with a sample rate of at least 44.1K, though higher is recommended if possible. If a 16-bit master such as an audio CD, upload through our MUA, or 16-bit WAV files is submitted, we cannot complete the MFiT process.

The second part of the MFiT process happens during the mastering session. Using tools provided by Apple, the mastering engineer will preview the mastered files through the same encoding process that Apple will use to create the AAC files that will be sold through iTunes. Based on that preview the engineer may make some adjustments to the mastered files in order to optimize the sound after the encoding process is completed. Another tool alerts the engineer to any clipping of the audio signal that is occurring during the AAC conversion. Based on this info the engineer can reduce the overall volume to avoid this clipping.

The result of this process is a file submitted to Apple that will yield the highest quality conversion to an AAC file for sale on iTunes.

Since the MFiT process does add time to a mastering session there will typically be an additional charge when a client is requesting this service.

FrequentLy asked questions

How should I submit my files for audio mastering?

Please submit files for audio mastering in their native recording resolution. We accept file resolution up to 32 bit/192KHz, WAV or AIFF. Once you have booked your session, we’ll contact you with a secure upload link. If you’re submitting analog tape, please call us to arrange shipment and discuss the session requirements.

What are ISRC codes and how do I get them?

ISRC, or International Standard Recording Codes, are 12-digit unique identifiers for your recordings. They allow an artist or label to track sales, airplay and royalties. ISRC codes are required by most digital distribution companies and music purchasing sites in order to sell your music online. This is different from a UPC code, which is used to track physical merchandise like CD’s and vinyl.

Apply for ISRC codes, and learn more about them, at

What does Mastered for iTunes mean and should I do it?

Mastered for iTunes (MFiT) is a set of guidelines created by Apple to accurately deliver an artist’s music on iTunes, adjusted for the best possible fidelity on your computer and Apple devices.

Infrasonic’s engineers are “Mastered for iTunes Certified” and work within the best practices of Apple’s encoding and file delivery requirements. To decide if MFiT is something you should consider, get in touch with us before booking your session.

Can I master my digital, CD and vinyl release at Infrasonic?

Yes! Many clients choose to streamline the mastering process and work with us for all audio and vinyl mastering. For more information about vinyl mastering, check out the FAQ’s below.   

Can I attend my session?

You can attend your audio mastering session for an additional charge, or schedule a tour of the studio before your project starts. Unfortunately we don’t offer attended sessions for vinyl mastering.

Where can I find your rates & pricing?

Shoot us an email at info [at] and we can provide you with a price quote. Our rates vary based on the type of project and engineer you are working with.  

I’m planning a vinyl release for the first time. Where do I start?

First, you’ll need to get your audio mastered. Infrasonic’s engineers master audio with your final format in mind, adhering to the necessary guidelines for vinyl. Next, you’ll place your order with a pressing plant (more info on that below) and get your master lacquers cut, which we do here at Infrasonic. This lacquer will be used to create your metal stamper. The stamper will be used to press your record.

Should I get a reference acetate cut?

We strongly recommend that our clients order a reference acetate, also called a dub plate. A ref will give you the chance to listen to your mastered audio on vinyl before your record goes into production at the pressing plant. This is different from a test pressing. Refs can often save artists a lot of valuable time and money should there be an issue with mastering, or if you decide to make minor changes to the audio or sequencing, before cutting. 

While listening to your ref, evaluate how your mastered audio translates on vinyl. You should listen for problems with levels, distortion and other audio-related issues, and contact your engineer if you have any questions or concerns.

What’s the ideal length of a 7”, 10” or 12”?

We have a set of guidelines for program length on vinyl, but each project varies. Depending on your material, we can cut a longer side or suggest other options. Here are the ideal (not maximum) lengths we recommend:  

7-inch:              6 minutes per side at 33rpm

                         2 to 3.5 minutes per side at 45rpm

10-inch:           12 minutes per side at 33rpm

                        8.5 minutes per side at 45rpm

12-inch:           18 minutes per side at 33rpm

                        12 minutes per side at 45rpm

What’s a catalog number and do I need one?

A catalog number, also called a matrix number, is a set of letters and numbers used to identify your record and yes, you need one. Artists and labels create their own catalog number, such as Infra-001 or XYZ-666.

We will etch the catalog number into the inner diameter of your vinyl lacquer. It will be used to keep track of your release during production and will appear on your pressed records.

What is scribe information?

Typically, your catalog number (see above) is etched, or “scribed,” into the inner diameter of your record, but you can choose to have additional information, or a personal message, included. For example, on Joy Division’s Closer LP, the message “This is the way” was etched into side A, and “step inside” into side b.

When should I place my order with a pressing plant?

You should place your order with the pressing plant before mastering your album at Infrasonic. If you’re unsure of what plant to work with, or have questions before placing your order, give us a call and we can help.

These FAQ’s didn’t answer my question. What do I do now?

Give us a call or shoot us an email and we’ll help you out.