This article offers you a detailed and sound comparison of the two legendary Neumann U47 capsules. We will talk about their history, their advantages and disadvantages, and make a voice sonority analyze of the two modern capsules sold on the Mic&Mod website to allow you to have an opinion on both and which one would be more prominent in your evolution or DIY project.
👉 This article will continue to evolve.
Historically, the M7 capsule was the first to be produced by the Neumann firm in the post-war period to equip the famous U47, the microphone that made the brand’s success because the greatest artists recorded with this model, such as Franck Sinatra, Elvis Presley, Jerry Lee Lewis, Ray Charles.
This M7 capsule was relatively heavy because it was made of raw brass with a membrane that had the particularity of being made with PVC, this membrane having therefore a rather limited life span. The M7 capsule was one of the first capsules to be equipped with the famous U47 model which became known in 1947 during a broadcast on a Berlin radio. Its mass production for the public will be delayed until 1949.
The M7 capsule was born from the evolution of the VF14 which had allowed Neumann to create the first signal amplifiers and thus of sound retranscription and in particular thanks to the creation of the double diaphragm.This M7 capsule can be set to cardioid or omnidirectional mode. Originally designed for the CMV 3 bottle mic, the M7 design has stood the test of time and is still manufactured today with an evolution of materials that make it much stronger. The M7 capsule will also be present for a few years on another mythical model of the brand: The Neumann M49.
Jerry Lee Lewis in recording session with U47 during 50’s
From the 60’s, a new capsule was born to replace the M7, it is the K47, which will be a condenser capsule, it will have the particularity to be made in a new material, the mylar this material will be much more durable than the diaphragm of the M7 which was in PVC plastic and subject to a relatively fast deterioration.
The Mylar film is extremely thin and resistant (except to shocks and fingers), only 6 microns thick, and is coated with gold for better conductivity. An electrical wire is mounted in the center which is called a “center-terminated” capsule.
With a single brass “back plate”, with an outer diameter of 34 mm, and equipped with two Mylar diaphragms, one on each side, which allows for optimal directivity. The diaphragms are fixed by a screwed tension ring, compared to the M7 capsule, whose diaphragms were glued to the back plate, and therefore much less optimal. With the combination of the electrical signals produced by the two diaphragms, it is therefore possible to produce several pickup patterns.
This new technology is still used today in the creation of modern capsules and has allowed the evolution of many capsules such as the K67/87 or the famous CK12 from AKG.
TESTS AND COMPARISON
Here is a test made by a German voice-over artist who was able to test the two capsules and give us feedback on the differences in the sound they produce. In his job, he is specialize in the creation of sound content, as well as for advertisements on German radios, or narrative voices, having the best rendering of his voice is essential, so he chose a U47 that he built himself.
These are 4 pieces recorded on the same text and the same intonation to really differentiate the two capsules.
The extracts are raw at the microphone output and made from the U47 of Mic & Mod.
Here is a first voice test at a distance of 10cm between the artist and the microphone:
“We advise you to listen with headphones for a more optimal rendering”.
TEST K47 (distance 10 cm)
TEST M7 (distance 10 cm)
Here is a second test performed on a distance of 30cm this time, the same raw recording of our voice tester without modification or mastering. Tests performed on U47 DIY by Mic&Mod.
TEST K47 (distance 30 cm)
TEST M7 (distance 30 cm)
Here are the frequency curves that we obtain on the comparative test between the two capsules:
In the end, after these voice tests and some tests of vocals and instruments that we will not miss to spread in order to make this article evolve. The capsules are relatively close and very centered on a very interesting oriented rhythmic to be exploited especially on vocals or low instruments. On our tests we found a slight advantage on the M7 capsule, this capsule is more smoother than the K47, but the latter defends itself very well!