Balanced Analog Crossover with Adjustable High-pass Filter

[morejazzplease]

It would be amazing if Fosi could design a balanced in-line crossover for integrating a subwoofer into modern two-channel stereo systems! There is a huge lack of preamps with HPF functionality and few affordable crossovers on the market for those of us who don't want (or can't afford) an active digital crossover / DSP device like a MiniDSP Flex. Modern subs have built in level controls, LPF functionality, phase adjustments and PEQs. Those features don't need to be built into this product! I think it would be great to keep this product simple: A in-line crossover with balanced inputs and outputs that features an adjustable HPF frequency which is applied to the balanced main outputs (to main speaker power amp) and a single-ended full range line-level subwoofer output.

Minimum Specifications:

• Balanced and Single-ended Line-level Inputs (Input from Pre-amp)
• Balanced and Single-ended Outputs (Output to main speaker amp - High-pass filter applies to these outputs)
• Subwoofer Line-level Outputs (not impacted by HPF)
• All analog adjustable HPF frequency setting from ~35Hz to 150Hz (dial adjustment would be ideal)
• SOTA noise, distortion, channel matching and frequency response performance (i.e., transparent)
• Non-grounded power supply (to stay consistent with non-grounded power supplies on most all Fosi equipment up and downstream)
• Switch on front panel to bypass HPF (when togged, the device would pass full frequency range to main line-level outputs)

The only thing that comes close to this on the market is something like the HSU crossover (~$450). But, the HSU crossover does not support balanced connections that are becoming more and more common on home audio gear! It also only has two fixed HPF frequencies that can be toggled between. Further, it has subwoofer volume controls but this is not necessary for most modern active subwoofers that have their own level adjustment controls. Finally, it is...quite ugly!

This crossover would not need any volume attenuation functionality as it is intended to sit between a preamp (or a source device with volume control) and power amps. This should keep the audio circuit path more simple and cleaner. A balanced crossover with these features would solve a major issue that many people are facing these days with integrating a sub to their system and being able to HPF the mains! It would appeal to the analog "purists" too as it can be an entirely analog device rather than performing analog-to-digital-to-analog conversions like a DSP device. You could even make a "lite" version with no sub output to target those just needing an adjustable HPF to their mains (as they are controlling the sub upstream).