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
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
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
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
AMP CTL (Amplifier
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.