Is There A Big Difference Between Subwoofers From Different Manufacturers

mitch2,

 Exactly what I am looking into doing, the simplest design possible, using quality parts of course. Much easier that replacing op amps, caps, etc without having a schematic, to change freq and have a cleaner signal on the sub amps crossover I am using. I will have to work out the value of the caps which I likely have on hand, the rest is quite easy. Since my mains roll off below 70 hz I will have to aim for that point but will try above and below it as well.

Sub amp is AB but unfortunately mono, wish I could fit two of them or have two smaller mono amps but it is a decent amp, more than enough power and has  variable phase, Q, single band EQ. Only issue is the op amps are moderate in quality and the crossover is a fixed slope of 12db at 80hz. I have been looking into swapping op amps to higher grade, caps, etc and changing freq to 70hz etc...but a passive is so much easier, and I can go from the DAC (R2R in the near future) directly to the tube amp without going through an op amp.

Rick

high-level connection is genius

No, it isn't as it does nothing to clean up the mains' low end. The interference between the mains and subs makes the bottom nebulous.

I'm sure all those extra connections and wire are destroying the sound 😉

Negative comments on REL SQ or build quality do seem to be rare.

Not many have heard properly integrated low end in a home HiFi.

Far too many sub integrations lean toward MORE, not BETTER. As a composer pal once remarked in my room "EVERY other subwoofer I've heard just boomed!"

Correction, I meant ieales, this forum operates a bit differently than I am used to.

I have built quite a few crossovers and never seen the formula written as you have and looked it up, could not find it anywhere.

* the same as x ?

R the same as impedance?

Thanks,

Rick

I'm not able to respond directly to the OP's first question, but according to my experience the choice of a sub (or more than one) depends also very much on your room and its acoustics - and, of course, on the quality of the components in your stereo system (low, middle, consumer, high end). 

I assume nobody out there knows or remembers the make of the sub I use: Acustik-Lab Stella Novus (original spelled name), a Swiss made component which was very in demand in Asia in its time (and very costly, unfortunately). It allows settings in many ways, which was prior to today's DSP. (The company no longer exists.) So my favorite crossover setting  is 42 Hz...quite discreet. With DSP and today's choice of subs you may find happiness, too. 

Acoustic-Lab Stella Novus sub, 15 – 500 Hz, adjustable, w/ remote control