The Blumlein Mic Technique Explained – Stereo Recording 101

blumlein mic technique explainedIn this post, we’ll present the Blumlein mic technique, explained for the beginner or the curious…

or for the producer and home studio owner looking to “spice up” their recording sessions with one of the most rewarding recording  techniques out there.

So if you’ve ever wondered what it is, and how you may use it, we’ve got you covered in this article…

Let’s begin!


Table of Contents


The Blumlein Microphone Technique

“Blumlein Microphone Technique” refers to a stereo recording method that captures the spatial characteristics of a real-world sound. It is known by many other names, including “Blumlein Pair,” the “Blumlein Configuration”, or simply the “Blumlein Technique”.

In any case, all these terms refer to the specific stereo recording method developed by someone named Alan Blumlein (Wiki link).

Blumlein’s goal was to record the spatial characteristics of sound as they occur in the real-world, and to reproduce them in a stereo recording. Its used for recording everything from drums and piano to orchestral ensembles and full bands, so the Blumlein Technique produces a remarkably wide and realistic stereo image.

To this day, it is one of the most effective methods for capturing a rich and complex stereo sound in a recording.

Origins of the Blumlein Technique

alan blumlein
Alan Blumlein

The roots of the Blumlein Microphone Technique can be traced to Alan Blumlein’s own early experiments with stereo recording.

While working as an engineer for EMI in 1931, Blumlein managed to reproduce the sound of one of Abbey Road’s soundstages. It was then that stereo recording became a reality.

Blumlein actually referred to his early experiments as “binaural” sound. Due to the unavailability of “figure 8” configuration mics, he captured the stereo effect using omnidirectional microphones.

Nevertheless, his 1931 patent application in the UK included a theoretical and rudimentary application of the Blumlein Pair using directional mics.

Consequently, Blumlein also invented the mid-side recording technique, which is another stereo recording technique used often by studio professionals.

Types of Microphones Used in the Blumlein Technique

Microphones in Blumlein TechniqueA number of companies have developed stereo ribbon microphones specifically for use in Blumlein pair applications. Among these are B&O, Royer, and AEA. However, you can use pretty much any good-quality ribbon or condenser mics for this purpose.

Manufacturers of stereo condenser mics such as Neumann and AKG have recommended the use of their mics for setting up Blumlein arrays. You may also use mics that have variable pattern settings.

Applying the Blumlein Technique to Specific Instruments

The Blumlein Technique can be applied to any instrument or recording where realistic stereo imaging is desired. It’s interesting to note Alan Blumlein originally developed the technique to record Mozart’s Jupiter Symphony at Abbey Road Studios.

Nowadays it’s become especially effective for drums and piano, as well as orchestral ensembles. It will produce excellent results in full band recordings as well.

Drums

With drum recordings, the technique works best when the mics are positioned overhead.

A good place to start is to have the mic arrays set right over the drum kit about four to six feet up off the ground. You may also try positioning the mics slightly forward above the drum kit.

These mic placements enable you to capture a good blend between the direct sound and the ambience of the room. The naturally-occurring high-frequency roll-off will also help reduce the harshness of overly-splashy cymbals. In order to get more of the room sound in your recording, you could simply raise the mic array a few inches higher.

Demonstration

Piano

Piano recordings will especially benefit from the proper application of the Blumlein Technique.

For this, you will want to place your mic array about one to three feet from the right side of the piano. The mics should hang over the frame, with their centers aimed directly at the middle ‘C’ string.

This placement is best suited for recording grand pianos, so you may have to adjust it for other types of pianos. Moving the mics away from the frame will help cut some of the low frequencies and blend in more of the room sound.

Demonstration

Utilizing the Blumlein Technique in a Recording Session

Blumlein Stereo TechniqueIn order to utilize the Blumlein Technique in a home recording setting, you will need to have a fairly large room in which to set up the mics. You will need a matched pair of mics that have a bi-directional or “figure 8” pickup configuration. These mics are to be placed at 90° angles from each other.

The ideal way to capture the desired stereo effect from a real-world is to have the transducers of both mics in the same exact space. Because this isn’t possible, the next best solution is to place the capsules as close together as possible, which would position one directly above the other. The mics should then be positioned in such a way that an imaginary line bisecting the angle between them will point toward the source of the sound.

When done properly, the Blumlein Technique will result in noticeable stereo separation of the recorded sound, as well as a distinct separation in the room sound.

The sound achieved with the Blumlein Technique is usually a balanced blend of the room sound and the direct sound of the source. In fact, the acoustics of the room often has a significant effect on the quality of the recording. For this reason, it is important to have a good-sounding room to begin with.

Ideal Positioning in a Room

Even with a great sounding room, you will still have to take the time to find the optimal spot in which to place the mics.

Try a few different places before doing a take. In some cases, the best sound can be achieved by placing the mics off to one side of the room or towards the back, rather than in the front and center.

If you are just starting to experiment with the Blumlein Technique, two mic stands will do in a pinch. Once you hear the lushness and realism that the technique imparts however, you will probably want to set up your mics in this specific configuration more often. At that point, it would be advisable to invest in a mic-stand adapter that will hold two mics in the desired position. This will make it easier for you to move the mics around as you hunt for the sweet spot.

Final Thoughts

The Blumlein Technique is an amazingly effective way to enhance the stereo image of your home recordings without having to spend a lot of money on expensive equipment and high-end digital enhancements.

Once you have experienced the wonderful depth and realism that the technique makes possible, you may never want to go back to conventional mic placement again.

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