much of what we base our decisions on in this hobby are theory, but which is the cleaner signal is not. whether we will hear the difference is subjective, I choose to err on the side of a cleaner signal, if others don't that's their choice.
And as you, I'm having fun spinning records on the theoretically superior design of my Well Tempered Lab Turntable lol.
Again, there is no question that preamp is cleaner by bypassing the amp. That is fact. That said, in the real world, the additional "noise" from the amp is typically several levels below imperceptible because any meaningful amp noise would be heard in the mains far more than in the sub. That does not mean lower noise line-level connection can't be the better option for a given system, but the typical case is that the "noise" will be audible.
The other side is that driving the sub with speaker-level inputs allows the sub to receive the exact same signals as the mains. This offers the
potential for the sub to more seamlessly integrate with the mains because they both receive the exact same signal. That is a also a fact. However, like reduced noise with preamp connections, there is no guarantee that the uniform signal across subs and mains will actually translate into audible benefits (it will very much depend on individual components/environments).
Both sides are facts, and neither side is inherently less worthy or more worthy than the other. Which is better in any real-world system will be situational based upon each individual components, listening environment, etc. The
only way to know which is better for your system is to try both to, first determine whether you can hear a difference at all, and then to decide which is better for your environment. That answer, of course, only applies to your individual environment, it will not be a general answer for all.
And here's the thing, I have said several times here I have nothing against using high level inputs, the two subs connected with the Jamos are using their high level inputs out of convenience. I'm just aware it's not the best connection method, that doesn't make it bad.
I don't think you have any basis to to determine that "it's not the best connection" other than presumptions that one side (lower noise) is more important than the other (same exact signal).
As I understand it, and apologies if I'm wrong (but it's hard to find your description with all these posts), you are using speaker-level out of necessity -- so you have some subs connected by line-level and one connected by speaker-level. I would say that this isn't an example of evaluating line-level versus speaker-level because you haven't compared the sound quality of each in an identical setting (again apologies if I'm not remembering right). As stated above, the only way to compare both options is to take the exact same mains and subs, in the exact same locations, and to directly compare the sound quality of speaker-level versus line-level to determine if you can hear a difference (first) and then determine which is your preference. Of course, whatever any of us find with our own testing will be relevant to our system/environment only -- it is not a referendum on what happens in all systems (no such generalization is possible).
