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

One of the best discussions on topic I've read here.  When I posed this question to Verity Audio they agreed with most of you to leave main speaker alone and adjust your sub. Thanks all.

This very issue -- how to apportion audio frequencies above the desired cut-off point to the mains, and leave the rest to the subs -- defined my "sub journey" for years until I finally put some time & $$ into a solution:

It’s an electronic crossover. Mine is a single-ended, variable crossover point model from Marchand, a designer well known for high quality crossovers. I bought this one used for ~$500, and it has worked flawlessly for years. I run the output of the preamp to the input of the crossover, which splits the frequencies into 2 output pairs:

  • High pass: Frequencies above the crossover point I chose, 75 Hz, go via RCA IC to the class D monoblocks (bel canto 600Ms) that drive Harbeth 30.1s in a nearfield/desktop configuration (strange but true)
  • Low pass: Frequencies below 75 Hz go vis a 2nd RCA IC to the JL Audio e110 sub, in which I have the internal crossover bypassed

This crossover has trim pots for each channel to adjust the output of the crossover in +/- 1 dB steps. Once that’s set, all volume control is done by the preamp.

The Marchand uses 24 dB/octave crossover slopes, which work quite well in my desktop setup with a variety of speakers. This component is very transparent: I’ve compared the sound with direct wiring through the amps to the speakers (no sub) vs wiring through the crossover (also no sub). I can’t hear a diffrerence.

Before using an electronic crossover, everything I did was stumble, fumble, audiibly inadequate. This crossover instantly made the problem go away.

Dear Sir;

I use a subwoofer with a hi pass filter on 12 pairs of speakers.  I own 1 way, 2 way, and 3 way speakers.  1 way and 2 way the high pass filter is set at 80hz. with 6 or 12db slope.  On small 1 or 2 ways I use 12db high pass slope for 5 inch and under drivers.  3 ways are set at 60 to 80hz with 6 db slope.  The low pass filter is permanently set at 24 db per octave and the crossover frequency is 70hz.

In my experience, 1 or 2 way speakers benefit the most. Sending the bottom two octaves, 20-40 and 40 to 80hz. to the sub makes things much easier for the little driver.  You should hear my Markaudio Alpair 10p's play Blue Man Group.  The reproduction quality is startling!

Hope this helps

Macguy  

Is it worth it to send the signal through another box of electronic junk just to eliminate frequencies below 80Hz? I'm not sure myself, so I am asking in earnest, not sarcastically. My main drivers (8") are running full range with no crossover at all (Ref 3A NEFES II)

I'm not sure about my above question, and was hoping for some responses. Personally I think it's about a 50/50, but others more knowledgeable may have a better informed opinion.