The Totaldac active crossover lets you get active bass without any additional components compared to a Totaldac DAC, delivering exactly the same sound quality as a Totaldac DAC.
Totaldac’s first products were digital active crossovers; this is Totaldac’s original area of expertise, backed by long-term feedback.
These crossovers are 2-stereo-channel or 3-stereo-channel DACs with built-in digital crossover processing. The inputs are digital (AES-EBU, coax, Toslink, USB, network, etc., like other Totaldac DACs and streamers) and the outputs are analog.
For example, a 2-way crossover has one stereo analog output carrying only the bass signal and another stereo analog output carrying only the treble signal. This replaces the crossover usually built into the speakers and lets you drive the drivers directly via two stereo amplifiers, one for the bass driver and one for the treble driver.
Such a crossover is also very easy to adjust when designing your own unique speaker, whereas each adjustment in a passive filter is difficult and costly.
Each filter slope can be set to 6 dB/oct, 12 dB/oct, or 18 dB/oct for low-pass, high-pass, or band-pass (Butterworth) filters, and you can also adjust time delay and attenuation for each channel. All these parameters are adjustable from the remote handset, and you can even change them while sitting at the listening position to find the optimum settings.
A master volume control is also set from the remote handset; it controls the level of the bass and treble channels at the same time. Only moderate slopes are offered and no EQ is provided, to keep the filtering simple and pure. If you really need EQ, you can still add a digital EQ or room corrector between the digital source and the digital active crossover.
The Totaldac crossover is also one of the very first that keeps the sampling frequency unchanged from input to output. No sampling frequency conversion is used because such conversions do not always sound transparent. As a result, you get exactly the same sound as the corresponding Totaldac DAC, with more channels and custom crossover processing in the FPGA, the heart of Totaldac DACs.
The treble channel crossover can be switched off from the remote; the DAC/crossover then becomes a standard Totaldac DAC that can be used in any traditional hi-fi system, in case you no longer need the active crossover.
The active crossovers can be based on the latest Totaldac DAC models, with the corresponding differences in sound quality and price.
Example of a system based on main speakers and custom subwoofers:
The most common example uses a pair of main speakers supported by a pair of subwoofers. These are not home cinema subwoofers, but only the best components and the best electronics, closer to concert sound than home cinema.
Here the subwoofers are simply a driver mounted in a cabinet, with no electronics and not even a passive crossover, so there is no limitation – just the best driver in a well-designed enclosure. A high-end amplifier drives this pair of subwoofers; for example, two Totaldac Amp-1-sublime amplifiers are used, one for the main speakers and one for the subwoofers.
The DAC is replaced by a Totaldac d2-biunity active crossover. This crossover sends only the 0 Hz to 95 Hz bass signal to the subwoofers and sends 97 Hz to 20 kHz+ to the main speakers. These frequencies are fully adjustable by the user from the remote control and display. Slopes can be set to 6 dB/octave (gentle slope), 12 dB/octave, or 18 dB/oct (steeper slope).
In this system, 18 dB/oct has been chosen for the subwoofers and 6 dB/oct for the main speakers. This means that the bass frequencies of the main speakers are attenuated but not completely suppressed. Frequency response measurements and listening tests have shown that this choice is optimal.
It is also possible to adjust the level of the subwoofers relative to the main speakers, to compensate for differences in efficiency due to the speakers, placement, or amplifier gain. You can save these settings and then simply use the master volume control to adjust the overall volume (this volume button on the remote controls all four channels).
A single button on the remote control lets you switch back to full-frequency range on the main speakers and mute the subwoofers, returning to the main speakers only.
Another menu allows you to set a delay (in centimeters), and this delay can be applied to the main speakers and/or the subwoofers to compensate for distance or phase shift. This would be impossible with a conventional subwoofer, which allows you to delay the subwoofer but never the main speakers.
