X-R interchangeable capsule microphone

Product summary

The X-R interchangeable capsule microphone consists of two components:  the capsule amplifier and eight available capsules.

Capsules

Polar Patterns (10mm capsule unless otherwise noted):

• cardioid:  vent holes without blind hole
• nearfield cardioid:  vent holes with one blind hole mark
• side-address cardioid: 14mm capsule, female RCA jack output only
  
• cardioid, low sensitivity:  vent holes with two blind hole marks oriented diagonally, representing high-frequency rolloff
• short cardioid:  short body with vent holes, male RCA output only
  
• hypercardioid:  vent holes with two blind hole marks oriented vertically, representing front and rear polar response lobes
• omnidirectional:  no vent holes, without blind hole
  
• omnidirectional, low sensitivity:  no vent holes with two blind hole marks oriented diagonally, representing high-frequency rolloff

The cardioid capsule is intended for general use on all sources where off-axis rejection is important, but a low-frequency rolloff outside the nearfield is not desired.

The nearfield cardioid capsule has reduced farfield low frequency response.  When placed within 30cm (1′) of the source, the capsule’s proximity effect will provide a natural tone on the source with excellent rejection of farfield low frequency signals.  It is recommended for instrument mount in more difficult acoustic environments where low frequency bleed from other instruments must be rejected.  It is also excellent in combination with the omnidirectional capsule using the acoustic low-pass filter; the combined pattern yields the natural low-frequency response of the omnidirectional capsule combined with the precise stereo image of a directional capsule.

The side-address cardioid is also a general use capsule, with better low-frequency extension and improved noise compared with the standard cardioid capsule.  The side-address cardioid is only supplied with a female RCA jack.

The low-sensitivity cardioid and low-sensitivity omnidirectional capsules have reduced sensitivity and increased SPL handling for close-mic techniques on very loud sources, such as drums or instrument amplifiers.  Both capsules have attenuated high-frequency response to yield a frequency response similar to dynamic microphones.

The short cardioid capsule is intended for use with 3D (ambisonic) surround applications.  Its reduced length is designed to minimize phase differences experienced in an ambisonic decoding matrix.  The short cardioid capsule is only supplied with a male RCA plug.

The hypercardioid capsule has superior rejection of off-axis signals.  It is especially intended for instrument mount or stereo recording in difficult acoustic environments.

The omnidirectional capsule provides the most natural response in a freefield or in the nearfield (as when mounted on an instrument).  It may also be used for farfield stereo recording in a spaced configuration using the stereo bar.  It may also be used with the table mount as a boundary microphone.  The optional equalization disc provides an on-axis high-frequency boost for enhanced directivity.

Capsules include windscreen.

X-R capsule outputs are inverse polarity.  The X-R capsule amplifiers and custom output cables are designed to route the capsule signal output to the inverting pin of the corresponding XLR output connectors, such the the signal at the microphone amplifier has positive polarity.

Capsule amplifier

The X-R microphone capsule amplifier is a microphone “body” that supports the X-R series interchangeable microphone capsules. The X-R requires +9 to +48V phantom power.  The X-R capsule amplifier is available in mono, stereo, and three- or four-channel output.

The X-R amplifier includes a standard 5/8″-27 thread mount microphone clip.

Input configuration

The mono capsule amplifier may be supplied with a female, male, or right-angle male RCA input.  Right-angle, female-female, and male-male adaptors are also available.

The stereo and multichannel versions are supplied with permanently mounted capsule heads:

• stereo: 120º
• three-channel left-center-right:  90º
• four-channel 2D surround:  90º
• four-channel 3D (ambisonic):  120º

Custom features

Stereo recording

Various stereo recording angles may be achieved by using RCA adaptor accessories between the capsules and capsule heads.  The capsule spacings and stereo recording angles with each adaptor are as follows (click on spacing for image):

* omnidirectional capsules do not resolve a stereo recording angle of less than 180º at less than 55cm spacing.  However, when used with the equalization disc, the resulting polar response becomes subcardioid at frequencies above 2kHz.  Thus, the recording angles shown for the omnidirectional capsule with equalization disc are derived for a subcardioid polar pattern.

Capsule mixing using RCA Y adaptor

Two X-R capsules may be connected to a single input with the RCA Y adaptor, which will mix the two signals from the capsules.  When used with an RCA extension cable, the Y adaptor mixes two discrete sources into a single microphone channel.  Also, the Y adaptor may be used to blend an omnidirectional capsule with a directional capsule.  This technique is especially useful with the acoustic low-pass filter, yielding a hybrid pattern with a directional high-frequency response and an omnidirectional low-frequency response.

Ambisonic decoding

When used on the four-channel 3D head, the short cardioid capsules have 4cm radius from the center of the head.  The capsule head output given above is “A” format.  This output must be mixed to “B” format (bidirectional response on three axes, plus omnidirectional) for further processing, using the matrix:

W (omnidirectional) = FLU + FRD + BLD + BRU
X (front to back) = FLU + FRD – BLD – BRU
Y (left to right) = FLU – FRD + BLD – BRU
Z (up to down) = FLU – FRD – BLD + BRU

The resulting ambisonic frequency response requires correction.  The recommended filters (low-frequency shelving, notch, and high-frequency shelving) to decode to B format are as follows:

W filters: +9dB shelf @ 120Hz; -7dB notch (Q=1) @ 5kHz, +9dB shelf @ 11kHz.

XYZ filters: +9dB shelf @ 120Hz; -11dB notch (Q=1) @ 4.5kHz.

Note that the low frequency shelving boost is not recommended for recording distances of less than 1m.

Output configuration

The mono version has an XLR-3-M output; the stereo version is available with either XLR-3-M (unbalanced) or XLR-5-M (impedance- or electrically-balanced) outputs.  Three- and four-channel versions have an unbalanced XLR-5-M output.

X-R capsule outputs are inverse polarity.  For the standard mono XLR-3-M output amplifier, the capsule signal is round to pin 3 (negative polarity), with an impedance-balanced output on pin 2.  Thus, capsule amplifier will yield positive polarity when connected to a balanced input amplifier via a standard XLR microphone cable.  When used into an unbalanced input, pin 3 should be connected as the signal lead.

The X-R capsule amplifier is also available with a transformer-coupled (mono only) or electrically-balanced output (mono or stereo).  The electrically-balanced output will increase output level by 6dB, and has twice the current draw compared to the impedance-balanced output.  The transformer-coupled or electrically-balanced outputs may be useful where a positive polarity output is required into an unbalanced input preamplifier (where phantom power is supplied by an external device), or where the higher output is desired.  The transformer-coupled output will also provide the best performance from low-voltage phantom supplies (9V-12V), and may have superior noise rejection compared with the other output options (70dB CMRR for the transformer-coupled output).

A mono X-R capsule amplifier has an optional switchable output, with the following selectable features:

• left switch position – low-cut filter, corner frequency 160Hz, 6dB/octave;
• center switch position – normal output;
• right switch position – -10dB attenuator.

The feature switch is set with a 3mm flathead screwdriver.  The switchable output is only available for mono input and either impedance- or electrically-balanced outputs.

For the stereo XLR-3-M version, the left channel is routed to pin 3, and the right channel to pin 2.  There is also a stereo noninverted output option, where the output is inverted from the input, yielding positive polarity output from the amplifier for the X-R capsules.  For this option, the left channel is pin 2, and the right channel is pin 3.  The stereo electrically-balanced or stereo noninverted output options require four amplifier circuits (3.2mA total current draw).

The output pin configurations for XLR-5-M versions are as follows (inverted unless otherwise noted):

Output cables

Custom output cables are available in a range of special formats to support stereo and multichannel output.  These cables are configured to route the X-R output pins to pins 3 of the XLR-3-M outputs, with impedance-balancing components on pins 2.  This will result in positive polarity when connected to balanced XLR input microphone amplifiers.

X-R microphone capsule amplifier specification:

Phantom Power Input: +9-52V (+12V minimum recommended)
Power supplied to capsules: +10V across 6.8KΩ

Current, per channel, with capsule, unbalanced, impedance-balanced, or transformer-coupled output: 1.0mA
Current, per channel (mono or stereo), with capsule, electrically balanced output: 1.6mA

Input Impedance: 6KΩ
Output Impedance: 75Ω (each pin); 150Ω (dual XLR stereo output cable)
Recommended Preamp Input Impedance: 1.5KΩ or higher

Maximum Input Level, 1kHz @ 1% THD: +10dBV / 138dBSPL (standard capsule)

Total Harmonic Distortion, 1kHz @ 0dBV: less than 0.005%
Total Harmonic Distortion, transformer output, 1kHz @ 0dBV: 0.1%
Total Harmonic Distortion, transformer output, 100Hz @ 0dBV: 2.0%

Frequency Response: 20Hz to 30kHz (-0.3dB @ 20Hz)
Frequency Response, transformer output: 30Hz to 20kHz

Noise: -124dBV unweighted, -127dBA

Weight, mono:  68g (2.4oz)
Weight, stereo or multichannel:  100g (3.5oz)

Dimensions. mono:  95mm x 19mmø (3 3/4″ x 3/4″ø)
Dimensions. stereo or multichannel:  125mm x 19mmø (5″ x 3/4″ø)

General capsule specifications:

Type: 10mm electret condenser microphone (measurement: 6mm; side-address cardioid: 14mm)
Power: +5V to +12V recommended; +3V minimum, 6KΩ recommended
Current: 0.5mA maximum

cardioid:

Maximum Level, 1kHz @ 1% THD: 132dBSPL
Sensitivity, 1kHz @ 94dBSPL: -34dBV/Pa, +/-2dB
Frequency Response @ 1m (-3dB): 100Hz to 12.5kHz
Polar Response, 90°: -5dB @ 1kHz
Polar Response, 180°: -13dB @ 1kHz
Self-Noise: 18dBA
Weight:  10g (0.4oz)
Dimensions:  32mm x 12mmø (1 1/4″ x 1/2″ø)

nearfield cardioid:

Maximum Level, 1kHz @ 1% THD: 132dBSPL
Sensitivity, 1kHz @ 94dBSPL: -34dBV/Pa, +/-2dB
Frequency Response @ 1m (-3dB): 250Hz to 20kHz
Polar Response, 90°: -6dB @ 1kHz
Polar Response, 180°: -16dB @ 1kHz
Self-Noise: 15dBA
Weight:  10g (0.4oz)
Dimensions:  32mm x 12mmø (1 1/4″ x 1/2″ø)

side-address cardioid:

Maximum Level, 1kHz @ 1% THD: 132dBSPL
Sensitivity, 1kHz @ 94dBSPL: -34dBV/Pa, +/-2dB
Frequency Response @ 1m (-3dB): 80Hz to 20kHz
Polar Response, 90°: -5dB @ 1kHz
Polar Response, 180°: -13dB @ 1kHz
Self-Noise: 16dBA
Weight:  23g (0.8oz)
Dimensions:  32mm x 19mmø (1 1/4″ x 3/4″ø)

cardioid, low-sensitivity:

Maximum Level, 1kHz @ 1% THD: 144dBSPL
Sensitivity, 1kHz @ 94dBSPL: -47dBV/Pa, +/-2dB
Frequency Response @ 1m (-3dB): 100Hz to 4kHz
Polar Response, 90°: -5dB @ 1kHz
Polar Response, 180°: -16dB @ 1kHz
Self-Noise: 30dBA
Weight:  10g (0.4oz)
Dimensions:  32mm x 12mmø (1 1/4″ x 1/2″ø)

short cardioid:

Maximum Level, 1kHz @ 1% THD: 132dBSPL
Sensitivity, 1kHz @ 94dBSPL: -38dBV/Pa, +/-2dB
Frequency Response @ 1m (-3dB): 125Hz to 20kHz
Polar Response, 90°: -6dB @ 1kHz
Polar Response, 180°: -16dB @ 1kHz
Self-Noise: 15dBA
Weight:  9g (0.3oz)
Dimensions:  22mm x 12mmø (7/8″ x 1/2″ø)

hypercardioid:

Maximum Level, 1kHz @ 1% THD: 132dBSPL
Sensitivity, 1kHz @ 94dBSPL: -34dBV/Pa, +/-2dB
Frequency Response @ 1m (-3dB): 200Hz to 10kHz
Polar Response, 90°: -10dB @ 1kHz
Polar Response, 135°: -10dB @ 1kHz
Polar Response, 180°: -3dB @ 1kHz
Self-Noise: 20dBA
Weight:  10g (0.4oz)
Dimensions:  32mm x 12mmø (1 1/4″ x 1/2″ø)

omnidirectional:

Maximum Level, 1kHz @ 1% THD: 132dBSPL
Sensitivity, 1kHz @ 94dBSPL: -34dBV/Pa, +/-2dB
Frequency Response @ 1m (-3dB): 20Hz to 20kHz
Frequency Response with equalization disc
Polar Response, 90°: -3dB @ 13kHz
Polar Response, 180°: -3dB @ 13kHz
Self-Noise: 15dBA
Weight:  10g (0.4oz)
Dimensions:  32mm x 12mmø (1 1/4″ x 1/2″ø)

omnidirectional, low-sensitivity:

Maximum Level, 1kHz @ 1% THD: 144dBSPL
Sensitivity, 1kHz @ 94dBSPL: -47dBV/Pa, +/-2dB
Frequency Response @ 1m (-3dB): 20Hz to 5kHz
Polar Response, 90°: -3dB @ 13kHz
Polar Response, 180°: -3dB @ 13kHz
Self-Noise: 27dBA
Weight:  10g (0.4oz)
Dimensions:  32mm x 12mmø (1 1/4″ x 1/2″ø)

measurement (discontinued):

Maximum Level, 1kHz @ 1% THD: 132dBSPL
Sensitivity, 1kHz @ 94dBSPL: -34dBV/Pa, +/-2dB
Frequency Response @ 1m (-3dB): 20Hz to 20kHz
Polar Response, 90°: -3dB @ 16kHz
Polar Response, 180°: -3dB @ 16kHz
Self-Noise: 22dBA
Weight:  8g (0.3oz)
Dimensions:  32mm x 9mmø (1 1/4″ x 3/8″ø)