Sub wiring help, high level speaker terminal to RCA line level Sub inputs

P.S. to my previous post: A **possible** issue I see in looking at the converter Miller suggested is that its description mentions that it provides "D.C. Isolation for noise reduction." That may mean that it puts a capacitor in series with its inputs or its outputs. Depending on the value of the capacitor (i.e., the number of microfarads) the result could be some degree of frequency-dependent rolloff in the bottom octave or two, depending also on the input impedance of the sub’s amp (which does not appear to be specified).

But given the very low price, there doesn’t appear to be any downside to giving it a try.

Regards,
-- Al

One question is if the input to the Sub is only technically used as a signal, not carrying any loads, wouldn’t I simply be able to use a straight cable from my speaker terminals with RCA’s plugs on the other end into the Sub? This would provide the same function as that converter without adding in extra resistors?

You would be putting much too high a voltage into the sub without the converter. At best the result would be having to use the sub’s volume control near the bottom of its range, where the control’s resolution would probably be very coarse, and where the two channels might be summed together in an unequal manner. Also, if for some reason the sub’s volume control was inadvertently turned up too high while the system is operating damage to the sub would be possible, as well as adverse effects on your ears and your blood pressure :-)

Regards,
-- Al

Use a Paradigm X-20 crossover if you can find one used. Speaker level in - RCA out. Phase, frequency, and level control included.

Here is the actual LOC circuit along with a very succinct explanation
http://www.epanorama.net/circuits/speaker_to_line.html

Study it. This is exactly what I did. It was worth it to me to install this circuit- really nothing more than 2 resistors and one short length of wire per channel- inside my amp. It is however a very simple circuit. Keep in mind it does not matter at all where this circuit is located. When you buy a sub with speaker level inputs the exact same circuit will be used only inside the sub. 

Also like the above link explains these are 1/4 watt resistors. They can be so small because hardly any power goes through them. Regardless of volume. Regardless of your amps power. Regardless of how much you turn it up. The difference between one LOC made for high power and one for lower power is not the resistor wattage. Its the resistor value. The 10k resistor isn't used to pass power. Its used to attenuate. A bigger amp would use a 20k or greater resistor, but it would be the same 1/4 watt value.

What this means, being so small, no heat output, you can put it anywhere. You could practically wire it into an interconnect if you wanted.

Also the parts are like $2. Total. Quality just does not matter. It might if you were using it to listen to the full range signal. In this case though, low bass only, waste of money.

How you do this depends on a lot of things I just can't know. What you like the looks of, for example. What interconnects you're using. What you may or may not be comfortable soldering or modding. You could for example very easily remove the RCA from the end of one interconnect, solder the resistors, and attach the wires at the end to your amps speaker binding posts. Direct from the speaker outs to your RCA ins.

That one link above, just the one page, contains a wealth of information. You just have to figure out your best way of making use of it. I did, and mine works and looks just as good as any professionally built component. Yours can too. You just have to decide how you want to do it. Heluva lot less work than boxing and shipping. Lot more satisfying too.

@millercarbon Thanks that's a lot of good info, I'll read up on it more closely, seems like real easy job. I ended up buying the Y-splitter to see how that works out in the mean time. I could already use some cheap stock rca's I have laying around to try out the resistors.