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High & low pass with subs?

The mains are a pair of KEF Ref 1s.  The subs are pairs of Velodyne HGS-15s and HGS-10s, used with daisy-chained SMS-1 bass managers that provide acoustic room correction.  I've been using 4th order 80 Hz low-pass.  I also have a passive Marchand balanced 4th order filter high-passed at a fixed 80 Hz.  My question is should I use the high-pass filter or let the Ref 1s run full range?  A tech at Ayre told me the passive balanced filter would not cause a problem between the 5/20 series preamp and amp.

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bdp24's avatar
bdp24
9,393 posts
 

There are proponents of each method. High-passing relieves the Ref and it's power amp of having to reproduce lower frequencies, which will improve the midrange sound quality of both. Does that come at a cost? Purists don't like to add any active electronics to the signal chain, especially ones thought to contain sound quality-compromising parts or circuits.

The Marchand passive filters use questionable (to some) techniques to get the job done; their active filters are more highly thought of. If you can find a First Watt B4, it's a great little, modestly-priced ($1500 retail) x/o, featuring all discrete parts: no opamps, no IC's. 1st/2nd/3rd/4th-order high-pass and low-pass filters in 25Hz increments from 25Hz to 3200Hz, and level controls for one of the two filters (for bi-amping with power amps of different input sensitivities).

mijostyn's avatar
mijostyn
8,152 posts
 
Always use a high pass filter on the satellites. You decrease cone movement on the woofers and lower their distortion. The problem here is you are mixing and matching woofers and cross overs. Just because both cross overs are 4th order 80Hz does not mean they have the same characteristics. Fortunately the SMS 1 has correctable phase angle. I think the advantages of a digital cross over outweigh using a passive. But try both and see what you think. I think you should also try crossing over at 100 Hz. The shorter wavelength makes it easier to match up. I cross at 125 Hz. try to keep the woofers up against a wall or in a corner. Keep the 15s up front just inside the Satellites. Try it with and without the 10s. Do let us know what you think sounds best. Running the Kefs full range will definitely not. If it does something else is wrong.
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