Group delay in subwoofers


I understand the phenomenon of group delay when subwoofers are connected to a preamp and that they need to be placed approximately 8 ft closer to the listener than the mains.  Is this also the case when connecting a sub through the speaker level inputs from an amplifier or is group delay much less of an issue in this configuration?

jc4659
Thanks, Erik.  I absolutely agree and would need to buy a processor to do it the right way.
Rythmik Audio subs come with a plate amp that includes a continuously-variable phase control. The control allows time-aligning woofers to speakers without physically moving either. The Rythmik PEQ model plate amps also provide both low level connection (on RCA jacks) and high/speaker level (on binding posts).
For real and detailed information go to soundoctor.com and get ready for some serious reading. Super informative and helpful.
I've read it and unless you have the tools and patience to be fanatical about it then you have to live with compromises which are clearly audible.
Jc4659, I spent the last 4 days dealing with sub setup and group delay. My experience was not to use the setup info from the manufacturer.  Did that and it was a waste of time. I did a lot of research and followed the advice given by soundoctor.com and referenced other sources. The first and very important step is proper placement within the environment.  Once I found the sweet spot I again followed manufacturers instruction and again wasted my time. I then followed the instruction by soundoctor.com and finally hit the nail and I'm now loving it. Enjoyed my fully properly integrated sub tonight from 5 to 7 pm. All the tools required were a tape measure, SPL meter and muscle power. Soundoctor.com information rocked my world.