It is difficult to optimally integrate bass loudspeakers or subwoofers.
At present, there are almost only digital crossovers for this purpose.
But who wants to convert back to digital in an analog high-end playback chain?
Our Crossover sets the crossovers anew.

Crossing over

The crossover is divided into two sections: The Low section for the bass loudspeaker or subwoofer (mono or stereo) and the Mid-Hi section for the top/main speakers.

The crossover frequencies for Low and Mid-Hi can be set individually from 50 Hz to 120 Hz in 6 positions.

The Low filter has a slope of 24 dB per octave. The slope of the MID-HI filter can be switched from 12 dB to 24 dB.

In Phase

Audio signals should come from the top speakers and bass loudspeakers or subwoofers in phase.
The crossover offers variable phase control for this purpose.

Use the toggle switch to activate the phase control (phase 0° or phase -180°) and use the control to establish simultaneousness.

If the phase control is not required, it can be switched off and thus disappears completely from the signal path.

One or two?

If you want to connect two bass loudspeakers or subwoofers (one for L and one for R), this switch should be set to stereo.

If you only use one bass loudspeaker or subwoofer, switch to mono. The crossover creates a mono signal of the Low frequencies and outputs it to both Low outputs (L + R).

“In practice, it is easy to integrate a subwoofer into an existing loudspeaker concept with the Crossover. Flexible, easy to adjust and with a sound that is undetectable when configured correctly: Respect, SPL!”

On or off?

If you prefer to run the top/main speakers full-range, you can switch off the MID-Hi filter.

Get rid of it

With the Low Cut filter all frequencies below 20 Hz can be filtered out.

This way, the power amplifier does not have to amplify inaudible low frequencies and the loudspeaker is relieved.

As long as you're having fun

The playback volume of the bass loudspeaker or subwoofer can be varied from -10 dB to +10 dB.

In addition to the purely corrective adjustment of the speaker system, you can add more bass into recordings that lack low end.

“Happiness is when the bass kicks in.”

Good ol' times

Two mechanical VU meters visualize the input levels for the left and right audio channel.

With the VU switch you can optimize the display for different signal levels.

Source of joy

The Crossover offers both balanced inputs with XLR sockets and standard inputs with gold-plated RCA sockets.

Low & Mid-Hi

On the output side, the power amplifiers or active loudspeakers as well as bass loudspeakers or subwoofers are connected to the Low & Mid-Hi output sockets by means of balanced XLRs.

This means that even long cable runs to e.g. mono power amps placed next to the speaker are possible without the risk of interference.

Everything under control – AMP CTL

The standby mode for up to four devices with 12V trigger input can be switched on and off via AMP CTL, together with the Crossover (AMP CTL Out). This is especially useful for connecting power amplifiers. But also the standby mode of the Crossover itself can be switched on and off by a preamplifier, such as the Director Mk2 or the Phonitor x, via AMP CTL (AMP CTL In).

Sounds good

With all devices of the Professional Fidelity series we develop not only according to plan, but also by ear. Many important components are installed on the circuit boards using Through-hole technology. This way we can ensure that we can use the best sounding components.

The VOLTAiR Technology

The 120V technology is our reference technology. The 120V technology is unique in the world. It operates at a DC voltage of 120 volts. This is four times that of IC-based semiconductor op-amps. In our Professional Fidelity series, we refer to this unsurpassed technology as VOLTAiR technology.

The 120V technology works with +/-60 V. To be able to handle such a high voltage, we have developed special proprietary operational amplifiers that can operate with a DC voltage of +/-60 V: the SPL 120V SUPRA operational amplifiers. This high voltage would destroy conventional components and operational amplifiers.

The 120V technology achieves exceptional technical specifications and sonic benefits. Technically, in terms of dynamic range, signal-to-noise ratio and headroom. Sonically, in terms of richness of detail and an absolutely relaxed listening experience.

By the way, the “120V” in the name of the technology has nothing to do with the local mains voltage from the mains power socket. This is about the operating voltage inside the device with which the audio signals are processed.

The mains voltage from the mains power socket is transformed to the required secondary voltage in the device’s internal linear power supply with toroidal transformer. Rectifiers convert this AC voltage into DC voltage required in the audio device.

VOLTAiR is a composition of the terms Volt and AirVolt is the unit for electrical voltage and Air stands for the unlimited space the music can breathe in.

VOLTAiR symbolizes the perceived limitless dynamics resulting from high audio voltage.

What exactly is that?

And what does it do?

Good questions need good answers.

And that’s what the 120V technology (VOLTAiR) video gives you.

Most audio devices work with an internal operating voltage of +/-15 volts and can thus process a maximum input level of +21.5 dBu. If a DAC, for example, has an output level of +22 dBu at 0 dBFS, level peaks of the music material would already cause overloads in the input stage of the device. All components in the audio device often operate at their limits. The result is an unsteady sound that causes stress and faster ear fatigue.

SPL devices with VOLTAiR technology can handle input levels of +32.5 dBu thanks to the higher internal operating voltage of +/- 60 volts – thus offering 12 dB more headroom. All components consequently operate continuously in the optimum operating range. The result is a very pleasant, natural and relaxed sound experience. So you can enjoy your music in every detail.

Home is where the heart is

That’s why we manufacture all SPL devices in our own production facility in Niederkrüchten on the Lower Rhine, Germany.

VOLTAiR is that good

In the lab, we pitted Phonitor xe against the best audio measurement system and found that Audio Precision could not measure VOLTAiR technology.

Replacing fuses and voltage selection

The replacement of fuses and the switching of mains voltages must only be performed by qualified technicians. Fuses must only be replaced with fuses of the same type and specifications.