AC Audio Online Music Shop, PA, Pro Audio & Live Sound Specialists

A.C. Audio: Online PA, Pro Audio and Live Sound Specialists Call us on 0113 386 9080 Send us an email: Home

Klark Teknik 31 Band Analogue Graphic Equaliser

Product Code: KLSQ1GRAPHIC
Manufacturer: Klark Teknik

Free mainland UK shipping available for this product

Our Price £458.99INC

Available within 5-7 working days

We accept Paypal

KLARK TEKNIK has been designing audio equalisers since 1975, and has an impressive back catalogue, which includes the DN27, DN360 and DN370 three of the industry's finest and longest-established designs.

The Square ONE graphic represents 30-years of KLARK TEKNIK's design expertise, offered at a more accessible price point, bringing superb audio performance within reach of the most budget-sensitive applications.

  • 45mm faders with integral dust guards
    Long-throw faders for maximum accuracy and resolution.
  • Signal present & Clip LEDs
    Maximum input capability of +22dBu.
  • Universal Power Supply
    Auto voltage-sensing, operates anywhere between 100-240V +/- 10%.
  • Fully balanced inputs & Outputs
    XLR & TRS connectors, both feature extremely high CMRR.
  • Relay activated bypass
    Continues to pass audio in the event of power failure.
  • Roadworthy 3U steel chassis
    Designed to withstand the rigours of the road.
  • PROportional Q filters
    The 'Q' or bandwidth of the Square ONE's filters is proportional to the gain applied, and so gives increasing focus on real problem frequencies. This also means that adjacent filters sum together with minimum phase error, providing smooth, ripple-free summation.
    This filter mapping is also implemented on the World-leading KLARK TEKNIK DN370, and is the most appropriate for live sound reinforcement.
  • High Pass Filters
    The HPF on graphic equalisers are used to remove unwanted subsonic frequencies (traditionally about 30Hz). The HPF on the Square ONE graphic is set at 80Hz. If using your Square ONE graphic with a large speaker system, then you will almost certainly be using an active crossover, which should provide appropriate subsonic protection. In this case, leave the HPF out of circuit.
    When using more compact loudspeakers, use the 80Hz. knee of the Square ONE HPF for maximising their headroom and efficiency (If using your Square ONE graphic with foldback loudspeakers which have an extended bass response, the HPF can still be used, in fact, useful results can be obtained by 'bending' the knee of the HPF, by boosting the 63Hz fader on the graphic).
  • Low Pass Filters
    The Square ONE graphic's LPF is fixed at 12kHz. This is optimal for stage monitoring applications, both loudspeaker and IEM systems, and will increase available headroom as well as providing HF drivers with some thermal protection against ultrasonic frequencies.
    When engaged simultaneously, the Square ONE graphic's HPF & LPF give optimal control of the operating bandwidth of most foldback (floor wedge & IEM) transducer systems.

Architects and Engineers Specification:

The Graphic Equaliser shall provide +/-12dB of boost and cut at 30 1/3 octave ISO centre frequencies from 25Hz-20kHz.

A Power On Led shall be provided.

The Graphic Equaliser shall meet or exceed the following performance specifications:

Frequency Response: +/- 0.5dB (20Hz-20kHz)

Distortion: (THD+N) <0.005% @1kHz, +4dBu

Dynamic Range: >112 dB (20Hz-20kHz unweighted)

The Graphic Equaliser shall allow have one fixed second-order high pass filter with an 80 Hz corner frequency and one fixed second-order low pass filter per channel with a 12 kHz corner frequency.

The Graphic Equaliser shall have an equalisation section by-pass and shall be fail-safe, that is the unit shall return automatically to the by-pass condition in the event of power supply interruption.

The Graphic Equaliser shall use centre-detented slide potentiometers arranged to give a graphical display of frequency plotted against level. The slide potentiometers shall have protective covers to inhibit the ingress of dirt and dust.

All audio connections shall be electronically balanced and use XLR and 1/4" TRS jack connectors.

The Graphic Equaliser shall be capable of operating from a 100-240V +/- 10% 50/60Hz a.c. power source.

The Graphic Equaliser shall be the KLARK TEKNIK Square ONE Graphic, and no alternative specification option is available.

Technical Specification:

Inputs - Two
Type: Electronically balanced (pin 2 hot)
Impedance (O): 20k

Outputs - Two
Type: Electronically balanced (pin 2 hot)
Minimum load impedance: 600 O
Source impedance: <60 O
Maximum level: +22dBu into >2kO

Frequency response
EQ out: ±0.5 dBu
EQ in (flat): ±0.5 dBu
Distortion (THD+N): < 0.005% @ 1kHz, +4 dBu
Noise Floor: <-90 dBu
Overload indicator: +19 dBu
Gain - 8 to: +6dBu

Equalisation - 30 Bands
Centre Frequencies: To BS EN ISO 266:1997
25Hz-20kHz, 1/3 octave
Tolerance: ±5%
Maximum Boost/Cut: ±12dB
High Pass Filter Slope: 12 dB/octave
Low Pass Filter Slope: 12 dB/octave

Audio: 3-pin XLR and 1/4" TRS jack
Power: 3-pin IEC

Power Requirements
Voltage: 100V-240V a.c. ± 10%
Consumption: <25W

Height: 133mm (5.25inch) - 3U High
Width: 482mm (19inch)
Depth: 205mm (8inch)

Nett: 4.4kg
Shipping: 5.4kg

  • UK Based Company
  • Part of A.C. Entertainment Technologies - has its trading origins over 45 years ago
  • UK Stock Holding
  • UK Warranty
  • Free Delivery Over £150
  • Great Prices
  • Over 20 Years' Experience
  • Specialist Advice
  • Fast Delivery
  • Finance Options Available

With years of experience supplying Businesses, Government Organisations, Charities, Schools, Colleges and Universities, we invite you to take advantage of our knowledge to help you make an informed choice, ensuring you are purchasing the best music products for your needs. With specialists in PA Systems, Pro Audio & Live Sound equipment on hand to answer calls and emails, you're in the best possible hands.

Contact us now to discuss your requirements or to request a quotation. Additional discounts may apply for educational establishments or size and value of order.

Purchase orders can be sent directly to or apply for your cash or credit account here. Terms and conditions will apply.

Share This Page

Seen it cheaper?

Dear visitor - firstly, welcome and thank you for visiting the A.C. Audio Online website!

We value your custom and pride ourselves on the customer service we provide to all our customers. As you'll no doubt appreciate, the service we provide comes at a price and consequently we have implemented a minimum order value of £59.99 (including VAT) for all orders placed. Unfortunately, lower value orders are not economically viable due to the administrative costs. Better control of our costs helps to improve our efficiency and allows us to carry on providing the levels of service you've come to expect.

We hope you enjoy your visit and if there is anything you need any assistance with, please don't hesitate to let us know via Live Chat, Email or Phone – we'd love to hear from you.