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Constant Q and proportional Q modes

Each frequency band consists essentially of two fully parametric equalizers: one for 
constant Q mode and one for proportional (or variable) Q mode, selectable per band. 
The PQ is the fi rst equalizer to offer both modes, endowing it with double equaliza-
tion power for demanding corrective and creative applications.

In constant Q mode, the selected bandwidth remains unaffected by the amplitude 
setting, making it the best choice for corrective applications (e.g. to eliminate 
unwanted frequencies). In proportional Q mode, the amplitude is reduced as the 
bandwidth is raised and vice versa. With the smallest bandwidth setting, the 
maximum amplitude r/- 11.5 dB, while it is reduced to +/- 2.5 dB with the 
broadest bandwidth setting. The Proportional Q mode is better suited for creative, 
sound-shaping applications, as a bandwidth-related amplitude allows for sensible, 
musically suggestive operation – with raising bandwidths, higher amplitudes are 
increasingly less useful. 

Con. Q Keys

These keys switch in the constant Q mode (illumination on) for each fi lter band. In 
proportional Q mode, illumination is off.

PLEASE NOTE: It is impossible to activate the ON and Con. Q keys simultaneously, 
please always press one key after another.

Link mode

All switching functions can be linked to operate both channels from one master 
channel. This is particularly recommendable for stereo operation. Both channels 
can be specifi ed as master channel. Pressing the central key with the arrow in 
left direction activates link mode with the left channel as master, pressing the key 
with  the arrow in the right direction activates link mode with the right channel as 
master.If the link mode is activated, you can bypass the complete PQ electronics 
by deactivating the ON key of the master channel (signals are routed from inputs 
to outputs), because the ON key of the master channel also activates the ON key 
of the linked channel. Deactivating the ON key of the linked channel only bypasses 
this channel, while the master channel remains active.

Functions and Operation

Summary of Contents for 2377

Page 1: ...Owner s Manual PQ Recording Equalizer ...

Page 2: ...le for any damages including loss of data lost profits cost of cover or other special incidental consequential or indirect damages arising from the use of the unit however caused and on any theory of liability This limita tion will apply even if SPL or an authorized dealer has been adviced of the possibility of such damage Sound Performance Lab SPL electronics GmbH P O Box 12 27 D 41368 Niederkruec...

Page 3: ...dinary equalizer Supplied parts PQ Recording Equalizer Externalpower supply transformator including both power cords Owner sManual Key features Pure analog discrete Class A equalization circuitry Constant Q and proportional Q modes selectable per filter band 124V internal operating voltage for clean consistent audio Discrete SPL SUPRA op amps with 150dB dynamic range Channel link mode for all switc...

Page 4: ... switch or knob To clean the case use a lint free cloth Avoid cleaning agents as they may damage the chassis Please support the back of the unit whenever it is being mounted into a 19 inch rack especially important when touring Setting the appropriate supply voltage The appropriate supply voltage 115V 230V must be set on the rear panel of the external power supply The fuse block left from the powe...

Page 5: ...e operating voltage found in most high quality audio gear 15 20 V and about twice as much as the highest voltages used in the best units currently available This extremely high voltage allows the circuitry to process an astonishing dynamic range of ca 150 dB and an amazing 34 dB of headroom virtually eliminating overloading of individual filter stages even when processing extremely high level signa...

Page 6: ...aising bandwidths higher amplitudes are increasingly less useful Con Q Keys These keys switch in the constant Q mode illumination on for each filter band In proportional Q mode illumination is off PLEASE NOTE It is impossible to activate the ON and Con Q keys simultaneously please always press one key after another Link mode All switching functions can be linked to operate both channels from one ma...

Page 7: ...equencies 670 Hz 16 kHz HF High Frequencies 1 2 kHz 28 kHz Bandwidth Bandwidth is adjustable between 0 1 and 3 7 Q in proportional Q mode and between 0 7 and 15 Q in constant Q mode The extremely high maximum bandwidth in constant Q mode enables tight selective control in precision applications Illuminated keys The PQ features illuminated keys that illuminate brightly when activated The final softw...

Page 8: ...d optimal audio quality always use professional grade cables and connectors The PQ comes with an external linear power supply featuring a toroidal transformer for optimal audio quality and dramatically reduced inductive disturbance interference Input voltage 110 120V 60Hz or 220 240V 50Hz Noise 100 dBu 60 V Dimensions Width 15 cm 5 9 10 inch Depth 24 5 cm 24 1 2 inch Height 7 cm 2 3 4 inch Weight ...

Page 9: ... Filter Band 1 5 ON B C 0 each Q Q1 Band 1 10 Hz Band 2 100 Hz Band 3 1 kHz Band 4 10 kHz Band 5 28 kHz Transmission bandwidth 10 Hz 100 kHz 3 dB Band 1 5 ON B C 0 Processed frequency range 10 Hz 28 kHz Phase 10 Hz 5 5 1 kHz 0 10 kHz 1 23 100 kHz 8 8 200 kHz 11 25 CMRR 75 dB 1 kHz Max Gain 34 dBu Band 1 5 ON B C 0 Housing mounting dimensions Standard EIA 19 inch rack chassis 4 units 482 x 176 x 39...

Page 10: ... authorized SPL warranty repair facility in the country where purchased or to the SPL factory in Germany in the original packaging or a replacement supplied by SPL with all transportation costs and full insurance paid each way by the purchaser or owner All remedies and the measure of damages are limited to the above services It is possible that economic loss or injury to person or property may res...

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