Active analog 2-way crossover
The Crossover is one of a kind.
It is analog! No DSPs, no AD/DA conversion.
It is active! It fits to all kinds of speakers.
You can tune crossover frequencies and phase response all in the analog domain in real time with real switches and controls. And –of course– with SPL's unique VOLTAiR technology. That means headroom, dynamic range and real sound in abundance.
When you add a subwoofers to your top/main speakers the crossover is most often digital. That is been sold as a plus – but it isn't. Because digital signal processing involves AD-conversion, DSP processing and DA-conversion. The audio signal undergoes significant treatments and at least the extra AD/DA conversion does not amuse audiophiles.
But now, here is the solution: the SPL Crossover. Fully analog, 120V-VOLTAiR technology, user friendly and amazing sounding.
The Crossover is split into two sections: the LOW section for the subwoofers (mono or stereo) and the MID-HI section for the top/main speakers.
The crossover frequencies for LOW and MID-HI are identical and can be switched individually from 50Hz to 120Hz in 6 steps.
The LOWpass filter is 24dB/octave steep. The MID-HIpass filter can be switched from 12dB/octave to 24dB/octave. Set to 24dB/octave both filters operate in a Linkwitz/Riley design.
The Crossover features a fully variable phase control to perfectly allign the phase of the subwoofer(s) to the top/main speakers.
The Phase control can be switched off and taken out of the signal path if not needed to maintain the shortest possible signal flow.
If needed, the toggle switch engages the Phase control at 0° phase or at -180° phase. From these two starting points the phase can be varied from 0° to +180° resulting in a full 360° phase circlewith the Phase control pot.
The LOW section features a Mono/Stereo toggle switch.
In case you have two subwoofers (one for each L and R) this switch should be set to Stereo. If you only use a single subwoofer this switch should be set to Mono. The Crossover generates a mono signal of the LOW frequency content and puts it out on both LOW outputs (L + R). You can decide which one to use.
The MID-HI filter can be switched on and off. This is useful in case the top/main speakers shall operate full range and only the LOW filter shall roll off the subwoofer at a defined frequency.
An additional Low Cut filter is provided to cut all frequencies below 20Hz. This is especially useful to relieve the power amplifiers from amplifying inaudible very low frequent signals that only cause the chassis to moves excessively.
The output level of the subwoofer can be varied from -10dB to +10dB. After setting the crossover frequency and aligning the phase the level is the third control parameter.
We have opted for a big knob because this control is not only to adjust the speaker system but it can also be fun to use when recordings lack bass content or the medium does not delivery much bass like vinyl.
The two VU meters show the volume units. It's mechanical design "slows" the measurement, averaging out peaks and troughs of short duration, and reflects thereby more the perceived loudness or 'energy'.
As the Crossover is operating after the preamplifier the audio level is rather low and the needle would remain left most of the time. For a better visibility the sensitivity of the VU meters can be increased with the VU toggle switch.
Another toggle switch allows selecting the levels to be displayed. The standard position would be "In" showing the input levels. The VUs can alternatively show the levels of each section LOW and MID-Hi.
When powering on the Crossover up to four other power amplifiers can be wire-linked for simultaneous power on/off. And if your preamplifier is a Director or Phonitor x you can power up the Crossover and up to four power amplifiers together.
To achieve this connect all units' AMP CTL sockets with 3.5mm mono-jack cables.