What is ambisonics?

Simply put, ambisonics is a way of representing sound in full three dimensions. It captures audio as one omnidirectional signal and three figure of eight signals, with the microphones facing left/right, front/back and up/down.

It was a process invented in the 1970s, but has really become practical with low cost, simple digital systems like the Brahma microphone. It is more complex than using a single-point stereo microphone, but the results are very much more rewarding.

In conventional recordings, much of the quality of the recording is determined by what microphones you choose (Omni, cardioid, hypercardioid) and how and where you place them. This gets frozen once you record.

In an ambisonic recording, much of this is still in your control after the recording. You can create virtual microphones of different patterns, angle and rotate them.

You can set up with eight or more loudspeakers and accurately recreate the sound you heard at the performance. Set up four and hear it without the height element. If you already have a 5.1 system, you can synthesise a 5.1 recording that is actually better than you would get with a multimicrophone system.

 

Brahma-in-Zoom

brahma-in-zoomBrahma-in-Zoom is the most convenient and most popular microphone we produce. It is an ideal introduction to Ambisonic recording methods: it requires no cabling or complicated setting of levels. It is a genuine ‘one button’ recorder and the two AA cells last really long.

Continue reading “Brahma-in-Zoom”

I lost my calibration file, can i get a replacement?

Yes you can. We  will store these files on the cloud, organised by microphone number, and will send them by email – the files are small. We provide a set on a small micro SD card, which contains software as well.

Other ambisonic mics are much more expensive, how can your mics be high quality at this price?

Initially ambisonic microphones – made by Calrec, called Soundfield microphones – were expensive because they were analog, which meant each microphone had to be trimmed to create  a B format signal.

In the last ten years, the technology has changed. The calibration is done in software, and the microphones themselves have become simple and light.

Apart from that, the pricing of each make of Ambisonic microphone is determined by the manufacturer. I built my first ambisonic microphones because I could not afford to buy the ones in the market. I want to keep the price as low as I can, so many people can buy these microphones and do these recordings.

There are currently three microphones with this level of quality and technology. In terms of price, Brahma comes out at the bottom , with Core Sound Tetramic in the middle and Sennheiser Ambeo on top. Brahma always comes with a calibration file – you don’t have to ask for it.

One way this has been possible is because we do not have a factory to make the parts. In Bangalore, it is possible to find small scale machine tool operators who will make the parts we need. The part that need the greatest precision – the tetrahedral frame for the four capsules, is printed in a  new high strength nylon, in a factory in the Netherlands.

Calibration of the microphones has also become easier, thanks to techniques that rely on quasi-anechoic methods. You need a high quality calibration standard, but do not require an anechoic chamber any more.

Precise calibration is the real secret of Brahma microphone quality. The process creates four virtual microphones of B format. It also aligns the frequency response of these four virtual microphones with the high quality measurement microphone used as reference.

How do you ensure calibration is accurate?

Calibration method for Brahma microphones was developed in collaboration with Prof Angelo Farina and his team at the University of Parma. He has measured the prototypes at an anechoic chamber before developing the processes we are using, and has compared the results. This is an ongoing collaboration and future designs will also be submitted to Parma for evaluation.

The process of calibration generates a set of 2d and 3d graphics of the frequency response and directional properties of the four synthesised microphones. Errors in calibration are caught at this stage. If there are errors in these graphics the microphone is calibrated again.

Of the currently produced Ambisonic microphones, only CoreSound Tetramic and Brahma provide these calibration files. Several big name microphones are providing microphones without individual calibration, even when it has been clearly shown to be  an unsatisfactory method.

How do I buy a Brahma mic?

Brahma microphones are sold exclusively online. They are made to order, and very often, to meet specific customer needs. Which is why we usually require up to two week delivery time after payment.

Click here to order and tell us which microphone you want. Once you are satisfied with your choice of microphone and it’s availability is confirmed we’ll discuss payment modes and ship your mic to you anywhere in the world.

Our preferred payment method is Paypal. We will create a Paypal invoice for the price of the microphone plus shipping costs as soon we receive your request. We can also accept bank transfer, by arrangement.

How are brahma mics made?

These microphones are hand produced, with a great deal of assistance from Meena. I design the microphones, the 3d parts needed for each microphone, the PCBs and the cabling systems. Meena does the soldering, from smt chips on the PCBs to capsules, and makes up the cables and connectors. There is a computer controlled infrared soldering station for the SMD assemblies.

The metal bodies are manufactured in small machine shops in Bangalore. The printed circuit boards are printed in a very modern facility in Gandhinagar, Gujarat. The tetrahedral frames are 3d printed in the Netherlands using a new and very strong nylon.  Microphone capsules, DIN and XLR connectors and high quality four channel cables are sourced from the US and China,

We match the capsules as sets of four. We check printed circuit boards as they are assembled. We then listen to each channel as it is wired up from capsule to the DIN connector. We then do a further test to verify that the right capsules are connecting to the right channels. It is only after this  that we calibrate the microphone, first measuring in quasi anechoic conditions in eight directions, and processing these measurements to create a set of FilterMatrix files that are unique to each microphone.

Why is it called Brahma?

Brahma has been the name we have used for my ambisonic microphones for ten years now. A play on the fact that in Hinduism  Brahma is a four-headed god.

Current models

At the moment we have four models of  microphones available.

*Brahma-in-Zoom, where the tetrahedral array is mounted inside the Zoom H2n

*a version where the array is mounted on top of the Zoom, with 25 mm capsules

*a freestanding  microphone with 14 mm capsules, with a DIN 12 M connector. This microphone  needs to be coupled with a high quality four channel digital recorder.

Brahma Ambisonic Studio Microphone using 25 mm capsules and low noise electronics.  Uses DIN 12 M connector. This microphone needs to be coupled to a high quality four channel digital recorder.

The new 2nd order microphone is currently being tested and will be on pre-order as soon as we have a callibration protocol in place.  We are also working on a second order all digital microphone. It is still at an experimental stage,

 

Prices start from 750 USD, plus shipping. Email us when you are ready to order