Is There A Big Difference Between Subwoofers From Different Manufacturers

@akg_ca - My understanding is that getting that high pass crossover just right is difficult and can be expensive.  The manufacturer of my speakers and subs suggested simply blending in the subs at a low frequency and letting my mains roll-off, which they do below 40 Hz, even though the subs have a built-in crossover.  He suggested this because he knows I use the set up solely for reproduction of music.  If it were a HT set up, he might have recommended using the sub's internal crossover.  Fortunately my 650 wpc amps have enough power to still sound good without rolling off the mains.

Vandersteen makes two high pass crossovers that I could try.  Unfortunately, the more expensive M7-HP model rolls frequencies off below 100 Hz, which is a little high for where I want to be with my subs and mains, and they list at $3,300/pair.  I would be more interested at around 50Hz and less than $1,000/pair.

@ieales

It’s simple to add a first order passive HP to roll the lows out of the mains.

Are you speaking about a line-level HP filter like the Vandersteen M7-HP High-Pass Filter? If that is so easy or simple, then why does the M7-HP appear to consist of multiple components assembled on a circuit board at a price of $3,300/pair?

I am not challenging your comment but rather trying to understand. The quality of a line-level HP filter is so important because the entire signal going to the main speakers passes through it. I doubt the HP filters provided in most subs are of a sufficient quality to handle that task without affecting the sound of the main signal in some way. The M7-HP filter (i.e., balanced line-level) is exactly what I need except I would want the pass frequency at 50Hz instead of 100Hz, and I would like to pay less than $3,300.

Based on the sonic benefit of relieving the main amplifier of reproducing the lowest level signals when subs are used, I am surprised there are not more aftermarket products like the Vandersteen filters or more information about how to construct a high pass filter using high quality parts.  At least one manufacturer includes a HP filter input in their amplifiers - the Aesthetix Atlas, but I know nothing about the quality of that filter.  Do you know of any websites where I might learn more about constructing a line-level filter like the M7-HP?

@ieales - Maybe I do not understand.

The Vandersteen M7-HP is in fact "an inline filter between pre- and power amps". It has an XLR input and output and is intended to be situated between the preamp and the power amp. The purpose would be to roll off the bass frequencies before they are sent to be amplified by the main amplifier and sent to the main speakers. A separate full-frequency line-level feed would then be sent from the preamp to the line level inputs on the subwoofers where their internal low-pass filter would determine the HF cut-off. In essence, this type of set-up is multi-amping because you have one amplifier powering the main speakers and the internal subwoofer amplifiers powering the subs.

@ieales - Thank you.

That is exactly the type of project I was looking for.  I would need it to be balanced.

The trade-off of course is whether the benefit of relieving the main amp/speakers of reproducing the lowest frequencies is greater than whatever detriment results from passing the signal through the HP componentry.  Marchand Electronics offers a balanced version (XM446XLR-A) for $525. 

My subs are also crossed over at about 40Hz but I can immediately tell when they are not turned on, which happens occasionally when I turn them off to insert new wire or make other changes and then forget to turn them back on.  Even at 40Hz, they seem to make a large difference in the quality of the sound from my system.  One feature I like about my Aerial SW-12 subs is the remote volume control, which allows me to easily adjust the sub/bass level by +1 or +2 when listening at low levels.  At more realistic listening levels, the 0 setting works great.

I did find another HP filter option that should cost less then the Vandersteen M7-HP.  It is the Marchand Electronics, Inc. XM446 Fully Balanced high pass filter.  I would be interested to hear pros and cons from any who have tried it, and particularly the sonic impact on the signal passing through the filter.