Re: Question re Subwoofer Connections, High-Pass, Low-Pass

On Mar 10, 12:51 am, JimC <avoc...@[EMAIL PROTECTED]
> wrote:
> My sub (a Velodyne F-1800RII), includes line-level inputs and outputs
> which permit high-frequency signals to be filtered out and sent through
> the line-level outputs to the power amp, essentially removing the bass
> from the signal fed to the power amp and providing bi-amplification.
> There is a high-pass filter switch which can be set to either 80Hz or
> 100Hz (6 dB/octave). There is also a variable frequency low-pass filter
> which can be adjusted between 40Hz and 120Hz (12 dB/octave initial,
> 48dB/octave ultimate).
>
> My question is: Assuming the low-pass crossover is set to 40Hz, and the
> high-pass filter is set to 80Hz, what happens to the frequencies between
> 40Hz and 80Hz (Ignoring signals that are outside the roll-off curves)?
> Are they simply lost?  In this system, the mains are Maggie 3.6 planars,
> with response extending somewhat below 40Hz, and I would prefer to feed
> bass above that frequency to the Maggies rather than have them
> reproduced by the subwoofer.  But with the above system, it seems that
> they would not receive any substantial bass below 80Hz. Also, what
> happens to signals sent to the mains when the Velodyne low-pass
> crossover is adjusted, e.g., adjusted between 40Hz and 80Hz or above?
>
> Presently I am not using the high-pass connections, and instead feed the
> full audio frequency spectrum directly to both the sub and the power amp
> (the preamp output is connected directly to the power amp and to the
> sub). This is because I had concluded that signals fed directly from the
> preamp to the power amp, without any processing or filtering, would be
> cleaner and provide a more transparent sound from the Maggies. On the
> other hand, it might be beneficial to remove the very low frequencies
> from the amp and the Maggies for greater efficiency.
>
> Any advice or suggestions? Do I need an external electronic crossover to
> resolve this issue?
>
> Jim

Are you sure the two crossovers are related to each other?  Does the
sub also have speaker thru-puts as well?  Is it possible that the
80/100 filter is part of connecting speaker outputs directly to the
sub and then connecting from the sub to the front speakers?  And the
40-120hz filter is part of the low level input?