2. speakers
  3. 194498-7564

Bass management--high/low pass filtering

A few days ago I posted to this forum seeking recommendations for a new subwoofer, and that discussion has turned out to be very enlightening, offering advice about subs and integrating them into my system. One reply mentioned the advantages of bass management for my main speakers (Ryan R-610 bookshelf speakers), but rather than sidetrack that discussion I thought I'd ask this separately:

It was suggested that I try cutting off the frequency response of the Ryans at 60 or 80Hz and letting the sub take over from there, thus relieving the mid/bass woofers of that substantial burden. On paper, this seems like a promising avenue to pursue, so I'm wondering if anybody has tried this and if there is a hardware device that can accomplish it. I'm certainly not an electrical engineer--far from it--so trying to design and build one is way beyond me. 

My integrated amp is a Modwright KWI200 and my previous sub (which is now dead and not repairable) was connected via speakon (speaker level) cable, though the Modwright does have a pre-out that can also be used to connect to a sub.

While pretty much all active subwoofers have adjustable low-pass filters, it appears that this would entail a high-pass filter somewhere in the chain. Is this something I can buy as an add-on? Couldn't find anything online, so I'm hoping that somebody may have some suggestions. Thanks.

cooper52

Showing 2 responses by knotscott

knotscott's avatar
knotscott
1,142 posts
 

Many subs have active high pass crossovers.  Lots of people use this configuration.

My setup has a separate preamp/amps....I split the preamp output signal and sent part of the signal to an active low pass crossover set at 63hz that then feeds the line level inputs of an integrated amp.  The speaker outputs of the integrated amp feed the 8" woofer of my main speakers, plus it feeds the high level inputs of my active subwoofer, and I set the low pass of the sub at 50hz with reverse phase. 

The other side of the preamp output feeds my monoblock tube amps....there is a 10nF silver mica capacitor that acts as a high pass inline filter that restricts low bass < 63hz to the tube amps, and passes everything else to the 5-1/4 midbass and tweeter that use a passive crossover.

I ran the above configuration without the inline high pass crossover (10nF cap) to the tube amps for a while, and I thought it made a notable improvement once installing it, but every situation is different so it may or may not be a good solution for  you.  I know it sounds complicated from a glance, but it’s not bad, and this setup evolved over time... it made sense in my case and has worked out extremely well for me.

knotscott's avatar
knotscott
1,142 posts
 

@koestner Is it worth it to send the signal through another box of electronic junk just to eliminate frequencies below 80Hz?

Depends on how the high pass filter is achieved, and also depends on the system and user, so the solution will vary accordingly.  

I’m bi-amping with tubes on the midbass/tweeter and a solid state amp to the woofers below 63hz,  and yes, I was concerned about junk in the signal path from my sub’s high pass filter.  

 My solution for eliminating the bottom octave(s) from the midbass was to use a quality silver mica cap to the amp’s input as a high pass filter (similar what GR research suggests. ...you need to know your amps impedance to calculate it.).

I'm ok with using a cheap active crossover for the low pass to the solid state amp below 63hz because it's in a much less critical frequency range than the high pass would have been.  This worked great for my situation, but may not for others.

More to discover