SMP- 1-PRO & UMP- 1 SMP- 1 - Shuffling microphone preamp The SMP-1 from phædrus is a high-quality, microphone and instrumental preamplifier featuring: transformer coupling (in and out); 70dB of gain; passive, inductor-capacitor, parametric EQ; a feed-forward, optical compressor; switchable phantom power; selectable high-pass filter; DI and line inputs; and a tube character control. As a stand-alone unit, the SMP-1 may be used as a universal input-processor for instrumental and vocal recording to a DAW or hardware recording device, or as an instrumental preamp. But the SMP-1 is much more than a mono, preamp. When two units are combined together (via an optional stereo-link cable (the SMP-link), the two units work in tandem as a unique stereo matrix which may be used to decode M/S, spaced omni and binaural microphone configurations to leftright stereo; as well as to correct for anomalies in figure-of-eight and cardioidmicrophone stereo-recordings. Even panned recordings benefit from a unique, head-shadow-compensation circuit; to create a compelling stereo image of remarkable accuracy and artistic potency. One SMP-1 has the following features: Transformer coupled on input and output Valve (tube) microphone-amplifier Inductor-capacitor, passive EQ circuits for vintage EQ-sound Feed-forward, optical compressor with unique RMS sensing side-chain Phantom power (selectable) +70dB of gain Balanced and unbalanced inputs and outputs all earth-free Pad, line and DI inputs for the widest of studio applications Hi-pass, linear-phase filter Variable microphone load impedance for that final tweak High-impedance, instrument (DI) input Valve (tube) character control from totally clean to grungy Two SMP-1s add the following operational features M/S microphone decoding with very low distortion and zero-latency Binaural (dummy-head) microphone to stereo transcoding* - enabling omnis to be used to make coincident, monocompatible recordings Unique treatment for coincident, cardioid setups crossed-fours configuration Unique head-shadow compensation - for all (even pre-existing) stereo recordings* Correction for crossed, figure-of-eight recordings to compensate for microphone beaming at HF Spaced-omni to coincident transcoding Stereo-link for compressors * See, What the link switch does
SMP-1-PRO Rear panel SMP-1-PRO Specifications Size: 220 x 109 x 45 (mm, L x W x H) Weight: <750g Power: 24V (via external supply), <5 Watts consumption Tube: CK6247 Gain: 0dB (line) to +70dB (at balanced output) Maximum input level: +24dBu (Line), +18dBu (Pad) Microphone input impedance: Selectable, >5k, 600 ohms, 200 ohms Phantom power: P48, to DIN 45596 (IEC 268 15A) Maximum output level (at balanced output): +24dBu Unbalanced output: -12dB, relative to balanced output, earth-free DI input: 1M input-z (sensitivity adjustable) Distortion: <0.1% (1kHz at 0VU), gain +26dB Compressor: >-20dBFS = 3:1, >-40dBFS but <20dBFS = 1.6:1, <-40dBFS = 1:1. Make up gain 9dB SMP-1-PRO Signal Processing Transfer characteristic of SMP-1-PRO at full tube drive (left) and the binaural shuffling process (right), indicating how left-right time cues at the microphones are converted to channel intensity cues at the loudspeakers. HF equalisation: frequency selection and boost curves
HF equalisation (shelf) and LF equalisation What the link switch does Use this mode to process any stereo recording, but especially recordings made using conventional pan-pots. (For example, you can use the SMP-1 as a line-level, stereo processor during mastering.) In conventional stereophony, the high-frequency stereoimage and the low-frequency stereo-image do not exactly coincide. The image above is an optical analogy of the problem. The head-shadow correction circuitry within the SMP-1 acts to correct the HF image, so that it coincides exactly with the LF image. The result is a stereo picture of unparalleled precision and realism. All, practical figure-ofeight microphones tend to "beam" and become more directional with frequency. The result of this narrowing of the high-frequency, directional response is a further distortion of the HF image with respect to the low-frequency one. This matrix position therefore introduces a greater degree of HF narrowing to compensate for HF beaming effects in crossed, velocity microphone recordings. The directional response of a cardioid microphone is equivalent to the combination of a cosine (figure-of-eight) and omni-directional response. (In fact, the earliest cardioid microphones were made in this way). So, the signals from a crossed-pair of cardioid microphones are mathematically equivalent to those produced by a crossed pair
of eights, mixed equally with a mono signal. It s not surprising this technique is often accused of lacking spaciousness. The truth is, the only reason the crossed-cardioid technique gives reasonable results is due to the HF "beaming" of the microphones which cause high-frequency channel differences to predominate over the mono signal at higher frequencies. One way to improve the situation is to set the microphones at a greater angle than 90 degrees of separate them slightly, so as to add a time-delay helper cue, as is done in the ORTF and NOS arrangements. But, it is also possible to correct for the effect of the unwanted, omni-response electrically; and that is what is done in the SMP-1 when the switch is in the! position. One special advantage of the electronic process is that the correction results in a suppressed rearlobe. Because this looks like half of an eight response, we term this technique, phædrus crossed-fours. Mid-side microphone technique is a well established practice. The SMP-1 contains the appropriate matrix to decode these signals to L/R. One unit should be set to m, the other to s. The greater part of Blumlein's (1933) patent is concerned with a binaural stereophonic microphone arrangement in which, "two pressure microphones a1 and a2 [are] mounted [20 cm apart] on opposite sides of a block of wood or baffle b which serves to provide the high frequency intensity differences at the microphones in the same way as the human head operates upon the ears". Blumlein noted that, when listened to with headphones, the direct output from the microphones produced an excellent stereo effect but, when replayed through loudspeakers, the stereo effect was very disappointing. The transformation Blumlein required was the translation of lowfrequency, inter-microphone phase differences into inter-channel intensity differences. To do this, he invented an ingenious circuit which he called the Shuffler. A modern implementation of Blumlein s circuit is implemented within the SMP-1. (back panel switch) This control adapts Blumlein s binaural transcoder to allow for widely spaced (1m) omnis. Ordering SMP-1 Shuffling microphone preamp + universal, external power supply SMP-link Stereo link cable SMP-stereo kit 2 off SMP-1 preamps, SMP-link and associated PSUs and cables
UMP- 1 UMP- 1 mic preamp & USB interface The UMP-1 from phædrus is a high-quality microphone and instrumental preamplifier designed to replicate the feature set of a single SMP-1-PRO but at a price to suit the pocket of the project studio. Like the SMP-1-PRO, the UMP-1 features: a tube-based, high-gain amplifier; passive, inductor-capacitor, parametric EQ; feedforward, optical compressor; switchable phantom power; selectable high-pass filter; DI and line inputs; and a tube character control. The UMP-1 does not include the stereo matrix functions available in the SMP-1- PRO, but instead adds a convenient USB interface with: high-quality analogue to digital converters for direct connection and recording to a DAW and DAC outputs for UMP-1 Specifications Size: 220 x 109 x 45 (mm, L x W x H) Weight: <750g Power: 24V (via external supply), 5 Watts consumption Tube: CK6247 Gain: 0dB (line) to +60dB (unbalanced output) Maximum input level: +24dBu (Line), +18dBu (Pad) USB support: Class-compliant, suitable for all personal computers and for recording and playback at bit-rates up to 96kHz and bit depths up to 24 bit. high-quality playback and zero-latency monitoring, for crisp tracking. The UMP-1 has the following features: Electrically balanced on input and output Valve (tube)-based microphone-amplifier with USB interface Inductor-capacitor, passive EQ circuits for vintage EQ-sound Feed-forward, optical compressor with unique RMS sensing side-chain Phantom power (selectable) +60dB of gain Pad, line and DI inputs for the widest of studio applications Hi-pass, linear-phase filter High-impedance, instrument (DI) input Valve (tube) character control from totally clean to grungy Monitoring output with mixable side-tone for crisp tracking Microphone input impedance: Not selectable, 5k Phantom power: P24, to DIN 45596 (IEC 268 15A) Maximum output level (balanced output): +12dBu (unbalanced is -6dB, relative to balanced output) DI input: 1M input-z (sensitivity adjustable) Distortion: <0.1% (1kHz at 0VU), gain +26dB Compressor: >-20dBFS = 3:1, >-40dBFS but <20dBFS = 1.6:1, <-40dBFS = 1:1. Make up gain 9dB Monitor output: 0dBFS = +8dBV (ie. 0dBFS = 18dB above alignment level of 0VU = -10dBV) Ordering UMP-1 Shuffling microphone preamp + universal, external power supply, + USB cable UMP-1-PRO as the UMP-1 but with input transformer instead of electronically balanced input Maidstone. Kent. United Kingdom contact: sales@phaedrus-audio.com