Hi
Working on a project and not able to sleep so ... WBF is the outlet to relax for a while
... Interesting subject: Subwoofers.
I will be blunt, the method of connecting a subwoofer whether from the speaker (High Level) or the preamp (Low Level) is the least important consideration in using a subwoofer.
Anyone with familiarity with speakers with powered woofers/subwoofer will attest that despite the method used the character of the main amps is revealed clearly, the character of an amp remains strong regardless of the method used to connect the subwoofers and since the vast majority of those (audiophiles) using subwoofers feed the subs from the preamp ...
Mojave posts are most important for anyone interested in using a sub. The notion of a overloading a room is not function of the size of a driver. it is true that the size of the driver has some impact on that of the subwoofer enclosure and one may not want the girth of huge subs occupying an already small space. We need to really focus on how to integrate a sub with mains.
To make it short, there are a few methods to use subs. They can be summarized this way.
The mains are run full range or however far they can go with no crossover in line with them to reduce the low to them or the mains amp.
The preamp output is followed by an active crossover that control / limt the amount of bass the mains get/reproduce.
I tend t think that the second method is the least used.
As for recipes to integrate subwoofers with mains. The two methods I know of are the Welti/Dvantier aka Harman method and the Earl Geddes method. They seem to be variant of each other. Geddes goes for quasi random positioning of the subs in the room while the Harman method recommend placement at fixed positions. As for the level , crossover, etc... That is where the difficulties occur .. Not a simple thing and requires knowledge and lot of measurements and yes, listening. Not a simple thing to accomplish. The results are however worth it. properly integrated subs in a system results in vastly superior musical reproduction and that for any type of music: From chamber to hip-hop or elecronica.