Subwoofer speed is in the room, not the box

@audioquest4life I listen to everything from Nine Inch Nails and The Red Hot Chili Peppers to Cherubini String Quartets. I have eight 12 inch drivers in a 16 X 30 foot room, each one powered by 2500 watts. I am into chest thumping as much as anyone. My subwoofers are EQed up about 6 dB so I can get the live concert experience at more reasonable levels. They run up to 100 Hz and are cut off at 48 dB/oct. I never change settings for any type of music and I can thump your chest into the next state and soar with The Lark Ascending, all on the same settings. The music has the choice of how it wants to sound.

@erik_squires Excellent! Speaker specs are worthless. Amplitude curves taken at 1 meter mean almost nothing. A speaker that goes down to 30 Hz at one meter might make it to 60 Hz in real situations. A speaker that is more omni direction is going to sound brighter, even sibilant in a room as compared to a directional speaker with the same specs. It is more important to understand what the design of the speaker is capable of and how to choose one that fits your needs and situation. Most people choose a speaker that looks good or suits their wife's sensibilities paying little attention to speaker design. They might look at the specs and if they do misinterpret them. Not all speakers are designed intelligently and some are awful.  

@mijostyn "A speaker that is more omni direction is going to sound brighter, even sibilant in a room as compared to a directional speaker with the same specs."

I'm curious: Besides tending to sound brighter than more directional speakers in real room conditions, are there any other general characteristics that you'd attribute to more omnidirectional speaker designs? Any typical differences in, perhaps, crossover frequencies with subwoofers? For example, is there any crossover frequency above which the often-noted "airy" or spacious quality of omnis could be impacted? I ask because I have a pair of Ohm Walsh 200 Mk-2 (semi-omnis?) that I'm still trying to integrate with a pair of subs that I recently purchased. Thanks! 

@mijostyn

"I listen to everything from Nine Inch Nails and The Red Hot Chili Peppers to Cherubini String Quartets. I have eight 12 inch drivers in a 16 X 30 foot room, each one powered by 2500 watts. I am into chest thumping as much as anyone. My subwoofers are EQed up about 6 dB so I can get the live concert experience at more reasonable levels. They run up to 100 Hz and are cut off at 48 dB/oct. I never change settings for any type of music and I can thump your chest into the next state and soar with The Lark Ascending, all on the same settings. The music has the choice of how it wants to sound."

That is great, I mean fantastic, and I don’t doubt you are having an excellent listening experience...I just need more than that. Liberal volume adjustments of the subs via the SMS do that for me. These are two different perspectives, and my way works great for my use. My new subs are a quad of 18" which will be added to the stereo setup. If I can’t shake the foundation, then 21" drivers are next. This of course is way off topic. Look, I am not speaking against optimizing the listening room and integrating subs as best as possible. We all must take the time to do that ensure we are getting the best from our systems. Been there done that and I feel okay with the way I integrate the subs. It just so happens to be different than that of others. There is no one way or the highway or absolutes in doing some things, it is all subjective, regardless of measuring. My ears will tell me and if they contradict measurements, so be it. I am not going to lose sleep or fret about it. I just want to enjoy what I have and tweak like the rest of us to our "own" satisfaction.

Sounds like you have eclectic musical tastes, same here. I could easily listen to Rush, Queensrÿche, Avenged Sevenfold, Bad Wolves, as well as Miles Davis, Rodrigo, John Coltrane, 1812 Overture, Pachelbel’s Canon, Wagner, etc.

BTW, listen to Tears Are Falling from Kiss and hear that drum by Eric Carr, the drummer at the time. Incredible playing. Sadly, he passed away from cancer. This is the type of drum beat that I like. In your system, I am sure it will be thunderous.

Happy listening.

@mijostyn wrote:

You want the sub running certainly up to 80 Hz and I will go no lower than 100 Hz. The solution to this problem is running steeper filters, not lowering the crossover point. The problem here is analog filters are terrible at this. You have to have a digital crossover then 8th order and higher is no problem. Running that high a high pass filter for the mains is mandatory or you will have a hot mess. This is advantageous anyway from a distortion and headroom perspective.

That’s a bit of an absolute. Generally we agree, but less than 8th order will do, and obviously it’s also co-dependent on the upper range performance of the subs. Tapped horns, that I use, are bandwidth limited by nature, meaning the lower the tune the more restricted the upper range extension. Even with the same tune though different implementations wrt. compression ratio (depending also on cone rigidity), the specific horn expansion, number of horn folds etc. will have implications on how ragged or not the upper range, outside its intended span, will be.

Long story short: even with limited upper end extension of my TH’s, sans corrections in their upper band, I’m applying a low-pass at just below 85Hz, 36dB/octave L-R with great results. Raising the LP just a single Hz or two however reveals a progressively more "rowdy" character - again, sans correction - towards 100Hz, so obviously the uncorrected upper range limit area is entered here. I intend to experiment with some corrections however, aided by measurements, and aim for a low-pass closer to 100Hz. Should be interesting to see the effect of that. As is the subs are essentially "characterless" with two minor PEQ’s in the central bass area.

Lastly here: I use the same slope steepness throughout into the mains, also the high-pass over the TH’s at 20Hz (though Butterworth style), and 48dB/octave didn’t fare as well sonically. To me in my setup context 36dB/octave L-R is the sweet spot; neither more or less.

Making an enclosure that does not shake or resonate is a very hard problem to solve.

Arguably it’s also a more pressing matter with direct radiating woofers and their mechanically induced noise to boot. Coming down to it I find enclosure "noise"/distortion is less of an issue than that created by the exposed driver itself, unless large quantities of drivers with larger diameter cones like in your (future) case are used, without solving the issue completely though.

Or, like in my case with partially hidden woofers with cones that move little due to high efficiency and excursion minima at the tune (that is, the horn/enclosure does the heavy lifting), contrary to sealed, direct radiating designs that are inefficient and have excursion maxima at the tune. Horn design cabs are also inherently braced from the horn path innards, on top of added bracings, and built with interlocked and CNC-machined 13-ply Baltic Birch panels, like my TH’s, are structurally very sturdy.

Small sealed enclosures are always best with subwoofers but you have to have a lot of power and high resolution digital EQ. Then you can make any sub run flat as a carpenters dream.

Per above paragraph of mine, I disagree.

If subwoofers and main speakers are integrated correctly there is no reason to turn the subs up or down with any genre of music. A system that is tuned correctly does not care what genre you are playing. When I use the term , system I include the room in that category.

Most audiophiles are ball parking it with their ears which are extremely poor calibration devices. There is no substitute for measurement.

I agree re: subs gain when correctly* implemented. With both music and movie reproduction I never change subs gain as it sits where it’s supposed to for overall balance, although I can understand if some would want to go bonkers with the subs gain lever to suit a particular mood and/or occasion.

With regard to measurements, they’re certainly indispensable in many regards and as an outset at least with some parameters, but to me it always comes down to fine tuning per ears as a last tweaking measure - if not in all aspects. Gain structure however I always fiddle into place by ears (like filter slopes), and that in 0.25dB increments; eventually I know exactly where it’s supposed to sit, and no measurement can tell me otherwise. So, it’s a both/and scenario here.

Great thread by the OP as usual  .... Interesting read...