Is There A Big Difference Between Subwoofers From Different Manufacturers

The room becomes less of a factor the more subs you add. With a swarm (4 subs) the room becomes almost a non issue.

No it doesn’t. The work done by Toole is for even bass everywhere, not accurate bass anywhere.

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?

No, an inline filter between pre- and power amps. THERE SHOULD BE NOTHING BUT WIRE BETWEEN THE POWER AMP OUT AND THE LS DRIVER TERMINALS. If everyone would multi-amp, the world would be a better place... and a lot of cable controversy would evaporate. I shudder every time I think about rollercoaster speaker phase response. 😢 Doubly so when tube amps are mentioned. The math makes my head spin. 😕

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!"

@akg_ca Spot on

It’s simple to add a first order passive HP to roll the lows out of the mains. The -3dB point should be slightly above the mains’ anechoic -3dB. Doing so effectively doubles the power available for the rest of the spectrum. Polystyrenes, while hard to find today, are preferred.

That being said, most subs today are missing some of the necessary controls

1. Multiple LP slopes
2. Multiple XO ’flavors’: LR, BE, BU...
3. Continuous phase control
4. Polarity inversion
5. Delay
6. Sufficient mass to prevent ’strolling’ on non-rigid floors above crawl spaces or on second+ stories

The Martin Logan X series has some of the above. The rest can added, if necessary, with external DSP. A failing of the ML series, other than Chinese origin, is insufficient mass. 10kg weights, while not particularly Audio Salon, are effective:

@mitch2

Sorry, I was lazy and did not look up the M7-HP. IMO, it’s overly complex and definitely overpriced. I eschew as many connections as possible. DIP switches have no- place/nowhere in an audio cct.

I’m talking about a simple passive HP for the mains and direct connect to subs.

The capacitor values are for the main amp and calculated C = 1 / ( 2 * π * f * R )

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.

There is no comparison. If you were adventurous, you could simply add the caps to the main amp input. Driver/box low end interaction problems simply disappear. The mains gain a large increase in mid-bass fidelity and articulation.

The Marchand look like decent units, but more complex than required. Another is Xkitz Electronics.

It’s not difficult to assemble a first order passive and with good parts, it’s 100% effective and nearly failure proof.

@tomic601

Replace some decade old dip switches. It’s usually pretty audible.

Rel subs are made as well as any commercial subwoofer.

Don't think I said anything about their build quality. My objection to them is the direction the company took. More bling and flash rather than useful features. WAF vs HPF