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Summary of Contents for Studer A1
- Page 1 Studer A Series Active Monitor Speakers Operating and Service Instructions...
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Page 15: Table Of Contents
4.3.1.4 A1: Supply Voltages ........................... E4/3 4.3.1.5 A1: Input Gain Check and EQ Preadjustments..................E4/4 4.3.1.6 A1: Input Common Mode Rejection Ratio (CMMR) ................E4/5 4.3.1.7 A1: Quiescent Current Setting ......................E4/5 4.3.1.8 A1: Woofer Amplifier Output ......................E4/6 4.3.1.9 A1: Tweeter Amplifier Output ...................... - Page 16 A Series Active Monitor Speakers A3 Service ..............................E4/13 4.4.1 A3: Settings on the PCB ........................E4/14 4.4.1.1 A3: Required Test Tools ........................E4/14 4.4.1.2 A3: Initial Settings ........................... E4/14 4.4.1.3 A3: Powering Up ..........................E4/14 4.4.1.4 A3: Supply Voltages ......................... E4/14 4.4.1.5 A3: Input Gain Check and EQ Preadjustments..................
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Page 17: Welcome
A Series Active Monitor Speakers WELCOME! We are happy to welcome you in the circle of the users of Studer's A series active speakers, and we felicitate you on your selection. Thanks to Studer's experience collected during more than 40 years of business in the profes- sional audio products field, you may expect that the performance of your new unit will fulfill your highest demands. - Page 18 In the Studer A series active speakers, these differences in the transit time of the audio signals are compensated by analog delay circuits maintaining the necessary delay up to frequencies above the audio range.
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Page 19: Safety And Connections
A Series Active Monitor Speakers Safety and Connections 1.2.1 Utilization for the Purpose Intended The Studer A series active speakers are designed for professional use. It is presumed that the units are operated only by trained personnel; servicing must be performed by qualified experts. - Page 20 ROLL OFF control. On the A1 unit the ROLL OFF control is not available, because this type and size of loudspeaker usually is not operated near room boundaries. E1/4 Welcome!
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Page 21: General
A Series Active Monitor Speakers GENERAL Scope of Delivery The Studer A series active speakers are shipped with an operating manual (order no. 10.27.4551), and either an IEC 320/C13 socket or an IEC mains cable, depending on your country. Options Order No. -
Page 22: Block Diagrams
TEMP. 115/230 V ±44 V ±17 V SENS. Σ LIMIT MAINS EMI LP ON/OFF FUSE MAINS RECT. REG. POWER TRANSF. Studer A1 FEED- BACK INPUT LIM. LEVEL INPUT FEED- BACK τ Σ 115/230 V ±38 V ±17 V POWER MAINS... -
Page 23: Technical Specifications
A Series Active Monitor Speakers Technical Specifications (preliminary, subject to change without notice) Input transformer-balanced electronically balanced Input impedance balanced, 5 kΩ balanced, 5 kΩ balanced, 12 kΩ Input sensitivity for 100 dB SPL @ 1 m 0.775 V Signal-to-noise ratio –100 dBA Max. -
Page 24: Operation
A Series Active Monitor Speakers OPERATION Connectors, controls INPUT: 1 = INPUT: 1 = CHASSIS CHASSIS 2 = + IN PHASE 2 = + IN PHASE 3 = – OPPOSITE PHASE 3 = – OPPOSITE PHASE SENS.: 775 mV = 100 dB SENS.: 775 mV = 100 dB (CAL. - Page 25 A Series Active Monitor Speakers INPUT: 1 = CHASSIS 2 = + IN PHASE 3 = – OP. PHASE SENS.: 775 mV = 100 dB (CAL. POSITION OF LEVEL CONTROL) ROLL OFF ROLL OFF LEVEL LEVEL ∞ ∞ ∞ ∞ ∞...
- Page 26 Potentiometer for matching the input sensitivity to your standard line level. Note: For the A1, this control is located on the front panel. [5] ROLL OFF (A3 and A5 only) Continuously adjustable bass cut filter, allows attenuation of the low fre- quencies in order to compensate for boundary reflections when the unit is mounted close to one (approx.
- Page 27 [7] Pilot LEDs All A Series speakers feature a green Power On LED. The A1 speaker is overload-protected by a limiter function without LED indicator. On the A3 and A5 speakers, the red Alarm LED on the front panel indi-...
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Page 28: Service Instructions
A Series Active Monitor Speakers SERVICE INSTRUCTIONS General Important! Repair work may only be performed by a trained service technician. The primary fuse must be replaced by a spare fuse of exactly the same type and rating. The unit must not be opened by the user – risk of a severe electrical shock hazard! •... -
Page 29: A1 Service
A Series Active Monitor Speakers A1 Service Measurement setup diagram: RT200 RT290 RT190 E4/2 Service Date printed: 29.02.00... -
Page 30: A1: Settings On The Pcb
A Series Active Monitor Speakers 4.3.1 A1: Settings on the PCB 4.3.1.1 A1: Required Test Tools Variable mains transformer (variac) True-RMS AC ammeter True-RMS AC voltmeter V2…V5 Digital DC voltmeter Sine-wave generator with balanced output (min. 20 Hz…20 kHz, < 0.02%... -
Page 31: A1: Input Gain Check And Eq Preadjustments
A Series Active Monitor Speakers 4.3.1.5 A1: Input Gain Check and EQ Preadjustments These preadjustments must be performed only if RT1 and RT2 are com- pletely out of range; these settings will be fine-adjusted on the assembled unit, also refer to section 4.3.2.5. -
Page 32: A1: Input Common Mode Rejection Ratio (Cmmr)
A Series Active Monitor Speakers 4.3.1.6 A1: Input Common Mode Rejection Ratio (CMRR) • Connect the generator in common mode to the input – i.e. “hot” generator output to both input terminals no. 2 (+) and 3 (–), “cold” generator output to input terminal no. -
Page 33: A1: Woofer Amplifier Output
A Series Active Monitor Speakers 4.3.1.8 A1: Woofer Amplifier Output Connect only the RLw dummy load (10 Ω) • Steps Generator Measurement No. Description Value Test pos. Type Value Limits Woofer output level –20 dBV/500 Hz/sine wave Level +3.5 dBV ±0.25 dB... -
Page 34: A1: Tweeter Amplifier Output
A Series Active Monitor Speakers 4.3.1.9 A1: Tweeter Amplifier Output Connect only the RLt dummy load (10 Ω) • Steps Generator Measurement No. Description Value Test pos. Type Value Limits Tweeter output level –20 dBV/8.1 kHz/sine wave Level 0 dBV ±0.25 dB... -
Page 35: A1: Limiter Threshold
A Series Active Monitor Speakers 4.3.1.10 A1: Limiter Threshold • Disconnect all dummy load resistors. Steps Generator Measurement No. Description Value Test pos. Type Value Limits HF limiter +10 dBV/10 kHz/sine wave M1 * Level +8.5 dBV ±2 dBV LF limiter... -
Page 36: A1: Checks On The Assembled Unit
A Series Active Monitor Speakers 4.3.2 A1: Checks on the Assembled Unit 4.3.2.1 A1: Required Test Tools Anechoic room; True-RMS AC ammeter; High-voltage generator 1.8 kV, 50 Hz, max. 10 mA; Sweep sine-wave generator with balanced output (AudioPrecision System One or equivalent);... -
Page 37: A1: Measurement Setup In The Anechoic Room
A Series Active Monitor Speakers 4.3.2.4 A1: Measurement Setup in the Anechoic Room • Setup the loudspeaker; • Setup the measurement microphone: Distance to the baffle 1 m, Equidistant from the two vertical edges, Equidistant from the centers of woofer and tweeter units (i.e., h = 16 cm), and Perpendicular to the baffle;... -
Page 38: A1: Spl And Eq Fine-Adjustment
A Series Active Monitor Speakers 4.3.2.5 A1: SPL and EQ Fine-Adjustment • Set balanced generator to 245 mVRMS (i.e. –12.2 dBV or –10 dBu); • Plot frequency response sweep @ 1 m: tolerance according to the graph below; • EQ fine-adjustment possibilities: 1. -
Page 39: A1: Polarity Check
Phase 0° ±20° *Note: Without compensation, the microphone Brüel & Kjær BK4133+2639 is inverting 4.3.2.8 A1: Overall Phase Check • Place the measurement microphone again on-axis, according to 4.3.2.4, distance 0.806 m; • Set the phasemeter propagation delay time to 2.91 ms (corresponding to a distance of 1 m);... -
Page 40: A3 Service
A Series Active Monitor Speakers A3 Service Measurement setup diagram: RT52 RT300 RT390 RT290 Service E4/13 Date printed: 29.02.00... -
Page 41: A3: Settings On The Pcb
A Series Active Monitor Speakers 4.4.1 A3: Settings on the PCB 4.4.1.1 A3: Required Test Tools Variable mains transformer (variac) True-RMS AC ammeter True-RMS AC voltmeter V2…V5 Digital DC voltmeter Sine-wave generator with balanced output (min. 20 Hz…20 kHz, < 0.02% THD) M1, Mw, Mt Voltmeter, THD meter, phase meter... -
Page 42: A3: Input Gain Check And Eq Preadjustments
A Series Active Monitor Speakers 4.4.1.5 A3: Input Gain Check and EQ Preadjustments These preadjustments must be performed only if RT1 through RT4 are completely out of range; these settings will be fine-adjusted on the assem- bled unit, also refer to section 4.4.2.5. Steps Generator Measurement... -
Page 43: A3: Input Common Mode Rejection Ratio (Cmmr)
(for 115 V), and note the measured value; Adjust RT390 (turn carefully clockwise) for a reading of: = A1 + 3 mA (for 230 V), or A1 = A1 + 6 mA (for 115 V), and note the measured value;... -
Page 44: A3: Woofer Amplifier Output
A Series Active Monitor Speakers 4.4.1.8 A3: Woofer Amplifier Output Connect only the RLw dummy load (10 Ω) • Steps Generator Measurement No. Description Value Test pos. Type Value Limits Woofer output level –13.6 dBV/500 Hz/sine wave Level +3.5 dBV ±0.25 dB Woofer output THD –13.6 dBV/500 Hz/sine wave... -
Page 45: A3: Tweeter Amplifier Output
A Series Active Monitor Speakers 4.4.1.9 A3: Tweeter Amplifier Output Connect only the RLt dummy load (10 Ω) • Steps Generator Measurement No. Description Value Test pos. Type Value Limits Tweeter output level –16.8 dBV/5.5 kHz/sine wave Level 0 dBV ±0.25 dB Tweeter output THD –16.8 dBV/5.5 kHz/sine wave... -
Page 46: A3: Limiter Threshold
A Series Active Monitor Speakers 4.4.1.10 A3: Limiter Threshold • Disconnect all dummy load resistors; Steps Generator Measurement No. Description Value Test pos. Type Value Limits HF limiter +15 dBV/10 kHz/sine wave M1 * Level +15 dBV ±2 dBV LF limiter +15 dBV/100 Hz/sine wave M1 * Level... -
Page 47: A3: Checks On The Assembled Unit
A Series Active Monitor Speakers 4.4.2 A3: Checks on the Assembled Unit 4.4.2.1 A3: Required Test Tools Anechoic room; True-RMS AC ammeter; High-voltage generator 1.8 kV, 50 Hz, max. 10 mA; Sweep sine-wave generator with balanced output (AudioPrecision System One or equivalent); Measurement microphone Brüel &... -
Page 48: A3: Measurement Setup In The Anechoic Room
A Series Active Monitor Speakers 4.4.2.4 A3: Measurement Setup in the Anechoic Room • Setup the loudspeaker; • Setup the measurement microphone: Distance to the baffle 1 m, Equidistant from the two vertical edges, Equidistant from the centers of woofer and tweeter units (i.e., h = 23 cm), and Perpendicular to the baffle;... -
Page 49: A3: Spl And Eq Fine-Adjustment
A Series Active Monitor Speakers 4.4.2.5 A3: SPL and EQ Fine-Adjustment • Set balanced generator to 255 mVRMS (i.e. –11.8 dBV or –9.7 dBu); • Plot frequency response sweep @ 1 m: tolerance according to the graph below; • EQ fine-adjustment possibilities: 1. -
Page 50: A3: Polarity Check
A Series Active Monitor Speakers 4.4.2.7 A3: Polarity Check • Place the measurement microphone at a distance of 10 cm from the baffle and exactly in the center of the woofer. Steps Generator Measurement No. Description Value Test pos. Type Value Limits System polarity... -
Page 51: A5 Service
A Series Active Monitor Speakers A5 Service Measurement setup diagram: RT300 RT390 RT200 RT290 RP11 RP12 RT52 RT190 E4/24 Service Date printed: 29.02.00... -
Page 52: A5: Settings On The Pcb
A Series Active Monitor Speakers 4.5.1 A5: Settings on the PCB 4.5.1.1 A5: Required Test Tools Variable mains transformer (variac) True-RMS AC ammeter V1, V1’ True-RMS AC voltmeter V2…V5 Digital DC voltmeter Sine-wave generator with balanced output (min. 20 Hz…20 kHz, < 0.02% THD) M1, Mw, Mt Voltmeter, THD meter, phase meter... -
Page 53: A5: Input Gain Check And Eq Preadjustments
A Series Active Monitor Speakers 4.5.1.5 A5: Input Gain Check and EQ Preadjustments These preadjustments must be performed only if RT1 through RT4 are completely out of range; these settings will be fine-adjusted on the assem- bled unit, also refer to section 4.5.2.5. Steps Generator Measurement... -
Page 54: A5: Input Common Mode Rejection Ratio (Cmmr)
A Series Active Monitor Speakers 4.5.1.6 A5: Input Common Mode Rejection Ratio (CMRR) • Connect the generator in common mode to the input – i.e. “hot” generator output to both input terminals no. 2 (+) and 3 (–), “cold” generator output to input terminal no. -
Page 55: A5: Quiescent Current Setting
(for 115 V), and note the measured value; Adjust RT390 (turn carefully clockwise) for a reading of: = A1 + 4 mA (for 230 V), or A1 = A1 + 8 mA (for 115 V), and note the measured value;... -
Page 56: A5: Mid-Range Amplifier Output
A Series Active Monitor Speakers 4.5.1.9 A5: Mid-range Amplifier Output Connect only the RLm dummy load (10 Ω) • Steps Generator Measurement No. Description Value Test pos. Type Value Limits Mid-range output level –17 dBV/1 kHz/sine wave Level 0 dBV ±0.25 dB Mid-range output THD –17 dBV/1 kHz/sine wave... -
Page 57: A5: Tweeter Amplifier Output
A Series Active Monitor Speakers 4.5.1.10 A5: Tweeter Amplifier Output Connect only the RLt dummy load (10 Ω) • Steps Generator Measurement No. Description Value Test pos. Type Value Limits Tweeter output level –15.6 dBV/8.8 kHz/sine wave Level 0 dBV ±0.25 dB Tweeter output THD –15.6 dBV/8.8 kHz/sine wave... -
Page 58: A5: Limiter Threshold
A Series Active Monitor Speakers 4.5.1.11 A5: Limiter Threshold • Disconnect all dummy load resistors; Steps Generator Measurement No. Description Value Test pos. Type Value Limits HF limiter +15 dBV/10 kHz/sine wave M1 * Level +12 dBV ±1 dBV MF limiter +15 dBV/1 kHz/sine wave M1 * Level... -
Page 59: A5: Checks On The Assembled Unit
A Series Active Monitor Speakers 4.5.2 A5: Checks on the Assembled Unit 4.5.2.1 A5: Required Test Tools Anechoic room; True-RMS AC ammeter; High-voltage generator 1.8 kV, 50 Hz, max. 10 mA; Sweep sine-wave generator with balanced output (AudioPrecision System One or equivalent); Measurement microphone Brüel &... -
Page 60: A5: Measurement Setup In The Anechoic Room
A Series Active Monitor Speakers 4.5.2.4 A5: Measurement Setup in the Anechoic Room • Setup the loudspeaker; • Setup the measurement microphone: Distance to the baffle 1 m, Equidistant from the two vertical edges, Equidistant from the centers of mid-range and tweeter units (i.e., h = 45 cm), and Perpendicular to the baffle;... -
Page 61: A5: Spl And Eq Fine-Adjustment
A Series Active Monitor Speakers 4.5.2.5 A5: SPL and EQ Fine-Adjustment • Set balanced generator to 250 mVRMS (i.e. –12.0 dBV or –9.8 dBu); • Plot frequency response sweep @ 1 m: tolerance according to the graph below; • EQ fine-adjustment possibilities: 1. -
Page 62: A5: Polarity Check
A Series Active Monitor Speakers 4.5.2.7 A5: Polarity Check • Place the measurement microphone at a distance of 10 cm from the baffle and exactly in the center of the woofer. Steps Generator Measurement No. Description Value Test pos. Type Value Limits System polarity... -
Page 63: Appendix: Frequency Response Measurements
A Series Active Monitor Speakers Appendix: Frequency Response Measurements (Most parts of the following paragraphs are reprinted with kind permission of Audio Precision, Inc., http://www.audioprecision.com) 4.6.1 General Frequency response measurement of loudspeakers is a much more complex topic than response measurements on amplifiers or most other electronic audio products. -
Page 64: Mls Technology For Frequency Response Measurements
A Series Active Monitor Speakers bly smoothed by one technique or another to improve measurement repeat- ability and reduce the visible effect of reflections to a value more consistent with a human’s ability to hear them. Even simple analog measurement tech- niques, where no “smoother”... -
Page 65: Quasi-Anechoic Measurements And Low-Frequency Limitations
A Series Active Monitor Speakers 4.6.4 Quasi-Anechoic Measurements and Low-Frequency Limitations Other techniques exist which provide measurement capability similar to maximum length sequence analysis. These include Time Delay Spectrometry (TDS) and impulse testing. They all provide quasi-anechoic frequency re- sponse measurements of the loudspeaker alone, unaffected by room reflec- tions. -
Page 66: Mls Advantages
A Series Active Monitor Speakers 4.6.5 MLS Advantages The maximum-length-sequence (MLS) test signal is a pseudo-random noise with special properties which allow analysis of response without the vari- ability commonly associated with noise-based measurements. The analysis technique provides a high degree of immunity from interfering noise, allow- ing accurate measurements when the interference actually exceeds the test signal level.
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