High Pass Filter for Mains

@mashif - mine is already posted but the crossover frequency is maybe too low for you at 45 Hz.

@mitch2 

What is the crossover point on yours? I need 80hz. Do you want to sell it? I ordered one today but it's four weeks out so I can still change my plans. 

I have the Marchand XM446 passive balanced high pass filter and it worked as advertised and seemed to add nothing to the sound of my system except for cutting off the low bass signal to my main speakers as it was designed to do.  However, since my main speakers are an acoustic suspension design that extends to 40 Hz, and because I roll the two subs in at a pretty low frequency of 45 Hz, after a year of comparisons I concluded the filter was not really needed in my system, but I haven't yet gotten around to selling it.  I suspect the filter would work great with most stand mounted main speakers and even some floorstanders that are being called on to do a bit more in the bass than they are capable of. 

@glennewdick 

I have 9 24x48x6 bass traps on the back wall and ceilings, and four 24x48x4 panels. They do a great job above 100hz. It's a small room and nothing is really gonna deal with below 80hz. I'm not sure this experiment is going to work but I won't know unless I do it. 

you may also want to consider acoustic treatment, IE bass traps to help control bass nodes etc.  

Thanks again for all the suggestions. I feel much better about Marchand and it's the right solution for my needs. I always prefer the simplest circuit with the fewest components. 

The SVS SB-1000 has dsp eq built in with app control. I definitely expect to utilize it. Otherwise I would just be duplicating my problem. If it works out, I would look to upgrade to a sub with variable phase. 

From 100hz up, my system is +/- 1.5db and sounds great. If I can get the frequencies below that to +/- 3db I'll be happy. 

I have alot of marchand and have no problems you can read the reviews say there noisy but I can't hear it.sublime acoustics make some .mini dsp you could get fast but have to use computer to program. Parts express carry some just a dial for two way high and low made out of salt Lake city.i do like electronic crossovers.put the sublime on my infinity irs v sound great you can change the cards in them to change crossovers but minidsp plug computer in change it all.many u tube videos  on them watch it.have some bryston 10 crossovers expensive.enjoy the music

Want to point out that even if you do use an analog crossover, a DSP EQ on the sub is still beneficial.  I would say if you can leave your high pass for your main amp and let the DSP handle the low pass for the sub, and everything else you'll find much better flexibility and easier time integrating the sub with the room and the sub with your mains.

I’m pretty sure GR Research, you can google their website, makes passive hi-pass filters.  They design crossovers for speaker manufacturers.

They will use much higher components than anything discussed above and they are very reasonably priced.

A cheap hi-pass filter will seriously degrade your sound.

I bought a 2-way electronic crossover from Phil Marchand last year.  It's built like a tank and sounds fantastic.  A very good friend is running the same Marchand crossover in his system, and it's been rock solid.

I've had a Marchand for over 20 yrs.  I've had Phil Marchand check it.  He has always been accommodating for me.  He uses good attenuators which make a difference and put new op amps for mine.

The new company Sublime looks to be comparable.

Thanks for the inputs.

I think I'm going with the Marchand balanced passive filters with a 80hz cross. It's $200 more but fits my connectivity better. What I meant about "a single cap" is its a single connection for me. Inside it's full of components. He offers 30 day returns so I'll order the sub when it arrives and have 30 days to evaluate. 

I'm just surprised with all the niche audiophile products out there, only one guy makes these. It makes me wonder whether this is an unusual endeavor in audiophileland. I've seen some previous discussions but no real conclusions. I'll report back when I complete the experiment. 

Op: A single cap is 6 db/octave.

Keep in mind that total rolloff is additive

  A sealed speaker is 12 db/octave so adding 12 = 24 total

This would work from sublime acoustics ($600) They also have one with balanced connections and use very good parts. Another option is an inline highpass from Harrison… it is $28 and sounds transparent to me. It will be 12db so use two if you want 24db.

https://www.parts-express.com/FMOD-Crossover-Pair-100-Hz-High-Pass-266-274?quantity=1

In my speakers, the tuned port is not just low end. It's a tube that terminates an inch from the back of the woofer. Plugging it muffles everything. 

The Merchand filter is 24 db while HSU is 12. It is essentially a single cap for each channel. I was hoping for an off the shelf alternative to waiting a month. I'm impatient.

A single cap, and plugging the ports can be very effective.   Hsu speakers also makes custom 2nd order line level

I went in a different direction, but researched these

https://www.bhphotovideo.com/c/product/752261-REG/dbx_234XS_234xs_Crossover_XLR.html

I don't know anything about them but ASR measured one and it measured better then its price.  

Same here, used their 3-way active crossover for years. Just recently sold it. I would have no problem buying from them again.

Many of the active subs have an output for the mains that offer a HP filter. I can’t speak to the quality of them, but they definitely exist, and some might be good. Lots of people do it and are satisfied.  

Another active option that’s really affordable is to use an automotive active crossover for the high pass. The Pyle 2-way is under $40. Add a 12V wall wart, and it’s a go. I’m using one for low pass only, and it’s been great in that capacity, but can’t speak for the quality of the high pass, but I’d imagine it’s on par with the HP options offered in most subs.

Marchand has been in business for decades. I had a Marchand crossover nearly forty years ago. It worked great, eventually a neighbor kid destroyed the speakers and replacement parts for the speakers were unobtainium.  Imo you can buy from Marchand with full confidence.