filters on speaker cables

I have a slightly long winded question on adding filters to my speaker cables to bleed of low frequencies. So is it possible to add a filter to each speaker cable to lessen to load on the amp when reproducing low frequencies? And if so what value,where do I get them, and how do you install them? I would like to add a stereo pair of quality subs to my system. I am using a Modwright KWI 200 integrated amp with Tyler Acoustics Woodmere II Speakers. I love the sound of the integrated but no way to add a crossover to the system as is. There are many here that say adding subs and lessening the load on the amp and main speakers has great results, so much so, that I really want to try it. So I am looking for another option without buying separates. Any advice is greatly 
It could very well be the way your room interacts with the speakers is causing your excess bass (if I read that correctly) and anything you do to the cables will be for naught. 

I have monitors that "only" reach down to the low 40s but I can measure response down to the low 30s and have more than enough bass to meet my needs. 

Using a sub can be advantageous since you can position it just about anywhere and adjust the output to a lower setting, which would alleviate some, if now all, of your problems. Others here know more than I so they'll chime in soon enough. :-)

All the best,
No such animal. If you want to use a sub with line level you will have to go with a separate amp and preamp.
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Thanks fellas, this is what I thought the response would be, I was just hoping someone knew more than I and had a solution. I will continue so save my meager wages to some day step up to good separates and the save even more to try the subs. I seem to have my heart set on reducing the load on the amp and main speakers, maybe I'll rethink that, thanks again, Allen.
Most subs have a built in crossover that will limit the base going to your main speakers. Do a search for subs and you will find many with built in crossovers
"Most subs have a built in crossover that will limit the base going to your main speakers. Do a search for subs and you will find many with built in crossovers"

True that most subs have a built in crossover, however, it is generally a low pass filter that has no effect on bass to the main speakers. A few do have a high pass filter that is necessary to limit the bass to the main speakers, and it is usually a line level connection. Speaker level high pass filters are rarely used nowadays.

I don’t understand how bass could be a problem. Four woofers in large cabinets that are spec'ed to 25 Hz with 400 watts per speaker, since they are 4 ohm. I’m thinking there is a problem elsewhere.

There is no problem with the bass response of the Woodmeres, like a lot  of people I'm just trying to find a little more and a better. That's what we do isn't it?
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Hello Bob, I have a 5.1 set up with a single Paradigm Sig 12 sub and use the HT bypass when watching movies. I will likely move on from this idea and dream up something else to obsess over, thanks for the good advice. I had read so many threads on here describing the benefits of two subs with crossover to lessen the load on main speakers and amp for two channel that I was hoping that I could find a way to try it without buying separates. Looks like that is what I'll have to do to implement what I am wanting to try, thanks again, Allen.
If the cables are of high enough quality filters should not be needed.

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Hello Bob, the preamp portion of my Yamaha AVR does not hold a candle the the one in the Modwright when listening to two channel music. I do realize that I could do it that way. But that is not what I had in mind. Truth be told it would have to sound pretty amazing to be better than what I listen to anyway, thanks, Allen.
Also the Yapo is not nearly as good as Audyssey, if only....
Contact Vertex as they offer frequency filters, one of which is connected between your amp & speaker using your existing cable.
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Was out of town for a couple of days with the grandkids, but I have spent some time,money and effort on treating my room, and YES it was a major step forward in sound, Thanks, Allen.
I’m in a similar situation to you... I have floor standers (that don’t even go as deep as yours) and two JL 12" subs, in a system that does double duty for HT and 2-Channel. I found an amp I really love, but it’s an integrated, and I had been banging my head over how to integrate the subs.

While I was also expecting the mains to get better, with the subs taking over bass, I haven’t noticed any difference. So I think your intuition to move on and obsess over a different aspect of your system is wise :) Where two 12" subs will make a difference, is providing deep prodigious tight bass, which is amazing if you watch movies or listen to certain types of music. So, if that’s what you’re craving, the extra trouble to properly integrate subs can be worth it--but if all you’re wanting is to improve the performance of your main speakers, I think you’ll be disappointed.