SPL - Sound Performance Lab Crossover

SPL crossover crossover

Finally an analog crossover again!

It is difficult to optimally integrate woofers or subwoofers in terms of sound.
Currently there are almost only digital crossovers for this purpose.

But who wants to go digital again in a high-end analog playback chain?
The SPL crossover sets the course again.

Set the course

The crossover is split into two sections: the low section for the woofer(s) 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 switching 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.

Contemporaneous

audio signals should come from the top speakers and woofers/subwoofers.
The crossover offers a variable phase control for this.

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

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 woofers or subwoofers (one for L and one for R), this switch should be set to stereo.

If you only use one woofer or subwoofer, switch to mono. The crossover generates a mono signal of the low frequencies and outputs this on both low outputs (L + R).

On or off?

If you would like to run the top/main speakers full range, then you can turn off the MID Hi filter.

take that away

With the low-cut filter, all frequencies below 20 Hz can be filtered out.

This means that the power amplifier does not have to amplify inaudible low frequencies and the load on the loudspeaker is relieved.

If it's fun

The output volume of the woofer or subwoofer can be varied from -10 dB to +10 dB.

In addition to the purely corrective adjustment of the speaker system, you can also breathe more “depth” into wonderfully low-bass music. True to the motto:

"Happiness is when the bass kicks in."

Good old times

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

With the VU switches you can optimize the display for different signal levels and select where the signal that is visualized here should be tapped.

Free choice

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 or bass loudspeakers/subwoofers are connected to the low & mid-hi output sockets using symmetrical XLR connections.

In this way, even longer cable runs can be implemented without interference.

Everything under control - AMP CTL

The standby mode of up to four devices with a 12V trigger input can be switched on and off via AMP CTL together with the crossover (AMP CTL Out). The connection of power amplifiers is particularly useful here. But the standby mode of the crossover itself can also be switched on and off (AMP CTL In) by a preamp such as the Director Mk2 or the Phonitor x via AMP CTL.

Sounds good

With all devices in the Professional Fidelity series, SPL not only develops according to plan from the outset, but also by ear. Many of the basic components are mounted on the circuit boards in through-hole mounting (THT). This ensures that the components that sound best are installed.

The VOLTAiR technology

VOLTAiR is made up of the terms Volt and Air .
Volt is the unit of electrical voltage and Air is the English word for air.

VOLTAiR symbolizes the seemingly limitless dynamics resulting from the high audio tension.

120V technology is the SPL reference technology. It is unique in the world of audio because it works with a DC voltage of 120 volts. This corresponds to four times the operating voltage of IC-based semiconductor operational amplifiers. They call this unsurpassed technology VOLTAiR technology in their Professional Fidelity series.

The highest possible audio quality requires the highest possible audio operating voltage.

120V technology operates at +/- 60V. In order to be able to handle such a high voltage, they have developed special proprietary op-amps that can operate at +/- 60V DC - the SPL 120V-SUPRA op-amps. This high voltage would destroy conventional components and operational amplifiers.

120V technology achieves exceptional technical specifications and sonic benefits. From a technical point of view, in terms of dynamic range, signal-to-noise ratio and overload resistance. In terms of sound, in terms of richness of detail and an absolutely relaxed listening pleasure.

Incidentally, the "120V" in the name of the technology has nothing to do with the local mains voltage from the socket. This is about the operating voltage in the device with which the audio signals are processed.

The mains voltage from the 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 the DC voltages required in the audio device.