KAM U Boat 4727 Sweet Sonic Flavors From One Microphone
3 Capsule Segment Choices: Center, Edge, or Entire Capsule
9 Directional Pickup Patterns
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Video of a mic shoot-out including AKG C12, Lawson L47, and KAM U Boat 47 is uploaded to youtube: https://youtu.be/FwISEdC-qHc <--- copy and paste this address in your browser to view
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Note: For more information visit the company website: www.kaminstruments.com .
This is a new product with never before available features. We will add sound samples, videos, and other support material.
This is the cutting edge of studio mic technology and we are are working on providing explanations, measurements, and guides on how to use the new features and approaches.
Variable Diaphragm:
Our patent pending diaphragm and capsule present a completely new concept in condenser microphones. Condenser mic diaphragms have been made essentially the same way for around 70 years. The diaphragm in U Boat 47 is divided into selectable electrically insulated segments. So using just two switches, either the center segment of the diaphragm, the edge segment, or the entire diaphragm can be selected to be active.
Sonic differences between segments:
The center segment sounds like a small diaphragm condenser, and as one would expect, using the entire diaphragm produces a large diaphragm sound. The edge segment presents an entirely new choice to audio engineers. The sound waves from an off axis sound source reach the edges of the capsule at different times. So for this size capsule, frequencies around 10 KHz, will have the highest part of the wave reach one side of the edge, and the lowest part of the wave reach the other. So sound waves from off-center sources substantially cancel each other. Keep in mind that part of the wave which reaches the center is substantially ignored by the capsule when only the edge segment is active. The overall effect of this is a darker tone from ambient sounds, and a brighter tone from sources in front. This creates a very pleasant mixture of the main sound source with sound reflections coming from the environment. Speaking only of frequency response, the edge segment resembles a medium sized diaphragm.
There are also resonance differences between the different segments. These are particularly relevant to tube mics. The reason tube mics have a "warmer" sound compared to transistor mics is that tubes amplify harmonic content of a signal, with even harmonics amplified more than odd harmonics. This creates a more pleasing and fuller sound which is also perceived as being louder.
In general, sound from any segment is refined and they all sound very good. you would not have a "bad take" from any of the choices. The subtle differences are a tool for experienced audio engineers with trained ears who like to optimize the sound quality in a given recording situation.
User Changeable Tube;
The heart of a tube mic is the tube! There are sonic differences between different brands of tubes and we wanted to make it easy for recording engineers to experiment with them. Removing only 2 screws provides easy access to the tube. There are no wires or components that need to be removed in the way. Initially, we will ship the mic with 7025 high performance tubes. These are compatible with 12AX7 and 12AU7 tubes. So there are many choices available. the screws at the bottom are 2.5 mm hex key screws so frequent removal of them will not cause wear on the screw head.
Head-Grill Design
The reflections inside a head-grill have substantial effects on the sound of a tube mic. The reason why tube mics are preferred for recording, is not that the output is more linear. Transistor mics can produce more linear results. Tube mics are used because they can enhance a sound, producing recordings that are more favorable than the original sound. We experimented with effects of different head-grill designs and chose the one that we found most effective in enhancing clarity and increasing the harmonic content of the signal.
Circuit Design:
The simpler the circuit in a tube mic, the more pure the sound. So a simple circuit made with high quality components is used in U Boat 47. The switches which select the diaphragm segments simply connect the appropriate segment to the circuit of the microphone. There are no additional electronic components used to achieve this.There are no "pad" or "bass roll off" functions included to avoid additional components for those functions which would reduce the purity of the sound.
Pickup Pattern Switching:
There are 9 pickup pattern choices; Cardioid, Figure 8, or Omni, and 6 more in-between choices. The selection is made using a rotary switch on the power supply.Frequency Response ChoicesThe combination of switches and pickup pattern knob positions result in varying frequency responses of the microphone, which provide a lot of flexibility in selecting an optimal frequency response for a given sound source. Also, the combinations of these choices interact with the reflections in the head grill providing more sonic flavors. The provided 8 frequency response graphs here on the listing are actual output from a measurement system. They are not manipulated for marketing purposes. Other in-between positions of pattern knob would produce results in-between those shown here.