Subwoofer speed is in the room, not the box

Hey @bjesien 

I beleive you.  The issue with subs, always, is integration. It is hard without measuremengs and nearly impossible with them.  I applaud Vandersteen's use of high pass filters, but recognize how hard the rest of it can be before you get good results.

@erik_squires wrote:

The biggest problems I’ve heard/seen have been excessively large peaks in the subwoofer range. Sometimes those peaks put out 20x more power into a room than the rest of the subwoofer. Think about that!! Your 1000 W sub is putting out 20,000 watts worth of power in some very narrow bands. Of course that will sound bad and muddied. The combination of sub and main speaker can also excessively accentuate the area where they meet, not to mention nulls.

A lot is made about nulls in the bass but honestly IMHO, those are the least of our worries. Of course too many of them can make the bass drop out, but in practicality is is the irregular bass response and the massive peaks that most prevent any good sub from functioning well in a room.

Either scenario (i.e.: peaks and nulls) in the extreme is one not to be desired. It’s their combination in particular that can tip the boat, but remember that corrected nulls require power; peaks don’t. So, peaks have one sitting with a surplus of acoustic power that can be counteracted with a narrow range of power suppression, whereas nulls have one in the need of actual, added electrical ditto. Thus, practically speaking power requirement can be the more predominant issue at hand.

If a distributed bass array is not an option we are dealing with frequency irregularities in the bass in the first place, even with pairs of subs, and the damn thing about absorption is that to alleviate peaks sufficiently, on its own, it can have a damaging effect on the overall presentation in other areas. I always go about sparingly with absorption, and would rather have the rest of the corrective measures done with digital room correction and/or a more manual approach with frequency correction via a DSP - preferably actively. On the other hand excessive use of DRC has its own disadvantages, or so I find, and so in the end there may be an element of one needing to accept an extent of FR-irregularities with a limited amount of bass sources. Or, a DBA is called for, and one placed symmetrically to the mains rather than a mono-ed asymmetrical ditto. 

Lastly, using a subwoofer to only fill in 20 Hz range is nonsense. Go big or go home. Use a sub at least at 60 Hz or higher. Use a single cap to create a high pass filter. Use EQ on the subwoofer at least. Get bass traps. Measure, for heaven’s sake measure and stop imagining you know a thing about your speaker or subwoofer’s response in the room because you don’t. Once that speaker arrives in the room it’s a completely different animal than it was in the showroom or in the spec sheet.

Definitely agree on the high-passing of the mains higher than lower - not only does it more effectively relieve the mains from LF but it also has you go about the overall integration with the subs much more effectively when controlling the HP of the mains over a range as well, which is akin to approaching it more as a single speaker system per channel than simply adding on the subs to the mains run full-range. There’s this misconception generalizing that high-passing the mains higher (say, >60-70Hz) is more suited to Home Theatre than "audiophile" use, which goes contrary to my own experience. To my ears high-passing higher (with a fittingly higher subs low pass as well) is usually more suitable on the whole.

With regard to "slow bass" I believe there’s some merit to considerations on overhang and/or group delay inherent to a design that will impact the presentation regardless of the integration with the room/FR-smoothness.

@phusis No one wants peaks or nulls, but IMHO and experience, peaks are worse. Of course, mathematically we can compute power differences for each, but peaks are bad because they tend to force the listener to keep the overall subwoofer level excessively low. OTOH, I’ve never seen a real system where the nulls were so pronounced that they forced an excess in sub volume. Maybe I got lucky.

In my experience, clipping the peaks and then raising the subwoofer level is 2/3rds of the battle.

The purpose of this thread was to discuss the myth of subwoofer speed, not any particular technology, and it invariably happens that SWARM fanboys show up and turn the thread into "WHY DON"T YOU HAVE SWARM" and take the discussion far afield from it’s intended point.

So, sure, any tech which evens out the peaks and nulls and correctly meshes the response of the subs to the mains is good, including SWARM, but this thread is about dispelling myths that you can’t add a sub to a "fast" speaker, not pushing any particular solution.

The sense of a subwoofer being bloated, or peaky or slow can be addressed with a single subwoofer or swarm. The problem is the finesse involved which first time subwoofer owners may be completely unprepared for.

Installing 1 subwoofer correctly is a big deal and a lot more work than most audiophiles want to do. Tripling the number of speakers (from 2 to 6) for SWARM is also a big deal for many. Failing to do either well is what makes for slow, mushy or overbearing sub experience.

Either of these approaches can dispell the myth that big cone subs are slow and unable to keep up with "fast" planar speakers. OTOH, lets be realistic that audiophiles are also unprepared for the work they’ll have to do in many cases to be done.

I guess my point is, I wanted to focus on all the problems which makes audiophiles call subs slow to point out how much has to be right.

In the service of that, I have no problem with users having very positive experiences with one approach or another (including SWARM) but would like to see more discussions about SWARM taken to their own threads. "How I solved all my bass problems with SWARM" would be a good title for a thread someone else starts I think.

I think audiophiles are 100% correct when they say adding a sub to a great sounding pair of speakers ruined the sound, but usually WRONG about why it went bad.  That's what this thread is about.