Digital Crossovers

Active Amplifiers

Measurement software
Coolback II 300

The very popular active
3-way "plate-amplifier"
with digital crossover
1757 € / 13000DKK
incl. TAX

1405 € / 10400 DKK excl. TAX

Availability as long as
stock lasts

- Don't wait too long
if you see something that
you would like to own !
Class H
Power Amplifier
2 x 2kW+ peak

The ideal Power Amplifier for
"power hungry" passive divided
loudspeakers or sub-woofers...
ONE word comes to mind:
"CONTROL" 2015 © Ground Sound * Products of Denmark
The Ground Sound philosophy is to always use active loudspeaker solutions based upon years of technical evaluations. There are only technical advantages when comparing active and passive crossover techniques. If you strive to make the best reproduction of a music signal with a cost no opject perspective the answer will always be to use actively filtered loudspeakers. Why is it like this, you ask… First of all we can quickly establish that the weakest link in the audio reproduction is the drivers of the loudspeakers, basically they have the highest distortion, the widest tolerances, narrow frequency response, limited dynamic range, dispersion varies with frequency etc. To get a full bandwidth reproduction sound system (about 20Hz-20kHz or more) you have to use multiple drivers covering different ranges in this frequency band. To do this you have to make separation between them as the drivers can’t cope very well with reproduction of frequencies outside their optimum frequency range. There are “full”-range drivers like Lowther, Manger, Fostex, but they do not cover the full frequency band, that normally are required and they do not have very high SPL capability. (SPL = Sound Pressure Level). It’s often seen that they are supplemented with a bass/sub driver and/or a tweeter…! The standard solution of multiple driver loudspeaker systems that you are offered in 99.99% of all manufactured 2-,3- or 4-way loudspeakers are passively divided. What is this passive and active dividing then, you ask…Passive dividing is made with capacitors, coils and resistors after the power amplifier – the power amplifier will have to control the entire loudspeaker with the result that it hasn’t control of the cones in the crossover points as these form an oscillation circuit, further the power amplifier has to produce much higher voltage swing/more power to give the drivers the signal in each of their frequency range adding up the electrical signal. This is a waste of power! This standard passive crossover solution will never solve this by using exotic materials in exotic components like Duelund Coherent, Mundorf MCap-Supreme Silver/Gold, Jensen Capacitors, Air Core Oxygen-Free Copper Foil or Zero Ohm coils. Components like these or similar are often used in the marketing of loudspeakers like Magico, Sonus Faber, Vienna Acoustics, Wilson Audio, Bowers & Wilkins (B&W), Dali, KEF, SpeakerCraft, JBL, Magnapan, Vandersteen, Acoustic Research, Anthony Gallo Acoustics, Apogee Acoustics, Avangarde, Dynaudio, Audiovector, German Physics, Gamut, JM Labs, Infinity, Klipsch, Linkwitz Lab, Linn, Usher Audio, Von Schweikert Audio, WLM Loudspeakers, YG Acoustics. The majority of High End power amplifiers are over-engineered to make a decent result on the pair of High End passively crossed loudspeakers. Just search your memories from visiting High End Show the last many years or search the web with Google or Yahoo. Quickly you will find companies like: Audio Research, Pass Labs, Mark Levinson, Krell, Gryphon, Primare, Bladelius, Accuphase, McIntosh, Bryston, Chord, Densen, Electrocompaniet, Gamut, Halcro, Vitus Audio, Jeff Rowland, Lamm, Parasound, NAD, Boulder, Vincent Audio, Audio Analogue – did I forget some… I hope I didn't insult those that I forgot. Another remedy to cure the passive crossover insufficiencies are expensive cables from companies like MIT Cables, Nordost, AudioQuest, Kimber Kable, Magnan Cables, Monster Cables, QED, Supra Cables, Tara Labs, van den Hul with exotic materials like 99.99999999% pure gold, silver and/or cobber, Teflon, snake oil AND the marketing explanations why to buy these cables are often just as exotic. To fight the course of the active solution in High End loudspeakers you can find a small number of companies like Lyngdorf, Holm Acoustics, Meridian, Tact, DEQX, Bakes&Müller and we at Ground Sound. It’s much more common to see active loudspeakers for the studio and broadcast environment. You often see active studio monitors from companies like Adam, Genelec, Dynaudio, KRK, Klein&Hummel, Quested, M&K and even JBL, Focal makes active loudspeakers for recording and mastering studios. When you go to a live concert that is “amplified” you will NEVER meet a passive PA loudspeaker system…!