Question about 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 appreciated, thanks, Mizike.

There is no way I know of to filter low frequencies without a cross over to separate the lows.  If you can separate the low frequency signals, there are many sub woofers which are powered. This would help the main amp.  The problem may be finding powered subs whose amps are as good as your main system amp.

I don't use subs myself, thus I would verify this with a sub person. best intentions-Steve

@Mizike It IS possible, but terribly uncommon and expensive.  IT also doesn't give you the full benefits of getting more dynamic range from the amp you are using.  Also, since this would be a high-pass filter, you would be adding some rather high capacitance values in series with the entire speaker.  Expensive to do with good quality parts.

What you really want is a line-level crossover. This is easy to do with a preamp amp combo, or with any integrated that has a pre-out and in.

Not all integrated units do this.

Among the best and least expensive solutions are the miniDSP units. They include crossover and EQ all in one.

Your best solution right now may be to run the main speakers "full range" and then add a miniDSP to the sub. This gives you the full quality of sound that your gear has, plus EQ and filtering to the sub.

One more tip.  If your main speakers are ported, plug them before integrating with a sub. This will slightly raise the -3dB point, but more importantly, reduce cone excursion, which will give you overall much better dynamic range with lower distortion.