Tight bass sub recommendations

ieales wrote: "Some liked the Bose 901 spread. Others thought it appalling."

I assume you are implying that a distributed multisub system is analogous to a Bose 901.

It is not.

The reason is, the way the ear/brain system perceives room reflections at low frequencies is different from the way it perceives reflections at mid and high frequencies.

At mid and high frequencies, early reflections primarily widen (or "spread") the image and degrade clarity, and often cause coloration; while late reflections done right enhance ambience and timbre with essentially no detrimental side effects.

At low frequencies, the ear/brain system cannot distinguish between the first arrival sound and the reverberant energy. I can explain this in more detail if you would like. But the implication is that the reveberant field is virtually all that matters in the bass region.

"Not all of us require homogenous bass through out the listening room. Some want it dead nuts accurate in one small area."

I think you’re using the word "homogenous" to imply that smooth bass throughout the room is somehow undesirable.

If your bass is "dead nuts accurate" in one listening area, then it is "homogenous" in that area, presumably from a combination of steps you’ve taken, probably including EQ. A distributed multisub system can expand that area, which is desirable to some people but obviously not to you.

The two different approaches are optimized for two different priority sets, but ime "accurate" and "throughout the room" need not be mutually exclusive.  Assuming budgets are not unlimited, it makes sense to optimize for your priorities.  That being said, I have customers who have gone from single-equalized-ubersub to a Swarm (EQ use optional) and preferred the latter even in the sweet spot. 

"If I play just the subs rolled off @35Hz on programme with very little real bass, I can still localize the subs and off centre bass blindfolded. Is that possible with ’homogenized bass’ from a swarm?"

Some upper-frequency energy will come through the subs because the electrical filter rolling off the top end of the sub is not a brick wall. This upper-bass/possibly lower mid energy is what gives away its location. In the absence of much louder energy in that region coming from the main speakers, of course the sub’s location can be heard. But most of us listen with the main speakers on, and the loudness discrepancy is great enough to mask the subs’ locations.

Duke

"Everything HiFi is a compromise."

Amen brother!!

And I agree with you that 105 Hz is usually too high for something like a Swarm.  I try to avoid letting the subs run up any higher than 80 Hz for exactly the reason you describe.

There is a technique that works in situations where the subs have to kick in fairly high.  I had a customer whose 107 dB horn speakers shelved down significantly around 150 Hz, before rolling off at about 80 Hz. (His midbass horn was imo too small to hold up well down to the manufacturer's claimed 80 Hz low end.)

What we did was, use two amplifiers.  We placed two of the Swarm units along the front wall near the main speakers, and those two units went up to about 130 Hz (which blended well with the downward-shelving of the mains at about 150 Hz).  The other two Swarm units went on the side and back walls, and were rolled off above 60 Hz or so (blending well with the ballpark 80 Hz rolloff).  The lowpass filters were all 4th order.  It did take a little while to dial in all of the settings even with measurement equipment, but when we were done it worked well enough that he took out his checkbook.  He was in a position to easily spend up to twenty times the price of the Swarm, so that was a nice outcome.

Duke