I recently upgraded my home theater with new LCR speakers, subwoofer, and receiver:
NHT C-3
Rythmik F-12
Onkyo TX-NR747
The overall room dimensions are 27' x 15' x 7.5' for a total volume 3000 ft^3.
The upgrade was made from BOSE 701 floorstanding speakers that I purchased in the 90's that were being used with an old Infinity center channel and NO subwoofer. The 701's were placed roughly where the bookshelf speakers are currently located, but about 18" away from the wall and sitting on cinderblocks to get the tweeters to ear height when seated. There are also low profile Infinity surround speakers on the walls beside the rear couch, but those are outside the scope of this issue.
My primary goals were to free up floor space in the combination use room and achieve a high level of audio fidelity. With those goals in mind I selected wall mounted bookshelf speakers and subwoofer, both acoustic suspension designs which my research indicated provide superior transient response and fidelity. The subwoofer is currently located on the mid-line of the room with the plan to add a second one at the opposite end of the room in the future to deal with any nodes I run into during calibration.
So imagine my horror when after completing the initial installation and setup, the new system has virtually no capability to produce what I will call "tactile sound". That is sound that you can feel, whether as a single impulse from a bass drop or cannon shot that you feel in your chest, or sustained vibration from a harmonic chord or thundering stampede of elephants where you can feel your clothing vibrating against your skin. The new system provides amazing fidelity at high frequencies; even the softest whisper in a movie soundtrack sounds like a real person in the room. And at the very low frequencies there is enough energy pumped into the room to shake the walls and rattle the windows. But sitting right in the midst of it, I've lost any and all tactile sound that my crumby old BOSE 701s could produce without a subwoofer. I hesitate to say that I'm looking for "tactile bass" because I don't think that the specific frequency range is the issue. As the dragon flies overhead and rains down balls of fire, or as the stampeded of elephants pounds across plains, my windows are rattling and the walls are shaking, but I'm trapped in an anemic bubble where I don't feel that satisfying tactile sound I love. (More on the bubble below. I'm not sitting in a node because there isn't tactile sound to be found anywhere in the room.)
So now that I've described the subjective problem, let me tell you what I've done so far to get to the root of the problem.
First I did a lot of subjective listening tests with movie soundtracks and EDM music containing a lot of high impact sound that should generate a tactile experience. I've ruled out acoustic nodes because no where in the room, including sitting next to the subwoofer, do I experience tactile sound. I've also ruled out insufficient headroom. The overall sound levels get painfully loud at -10dB on the receiver, which maxes out at +16dB. I've also tried turning up the subwoofer gain to maximum from its current calibrated state somewhere roughly in the middle. Doing so makes sustained bass sound ridiculously loud, but no more tactile.
Second, I broke out my Smaart rig to take some objective measurements of frequency response. While there are clearly some acoustic interactions going on, there is clearly plenty of bass energy extending well below 20Hz.
The white trace is where I'm at now. The purple trace was prior to me figuring out that the Accu-EQ feature of my receiver was doing more harm than good (notch at 150Hz) in my particular situation and so has since been disabled and I'm running a flat EQ. Both traces are actually averages of three points across my primary seating area so any fluctuations remaining are not highly localized artifacts.
So subjectively and objectively I can show that the system is generating sound energy across the full audible spectrum with some acoustic fluctuations that are not surprising given my relatively small room. But I don't think that alone can explain my lack of tactile sound. Remember that I previously had two BOSE 701 floorstanding speakers in the same space, being driven with less wattage, and with no subwoofer support and they had no problem with high impact tactile sound.
So now I'm turning to the good contributors at Audioholics for help. Since the original install, I've been doing more reading about acoustic suspension speaker design and I think I may have made an error by going that route. While most of the literature on the benefits of acoustic suspension talk about fidelity in terms of resonance, damping, Q, etc, they don't talk about the other side of the impulse... the UP side. I have found a few white papers suggesting that acoustic suspension designs are not capable of ramping UP sound output as steeply as bass reflex designs. I haven't been able to find any objective analysis on this, only subjective descriptions indicating that acoustic suspension designs are less "dynamic" which could possibly be describing the rising side of the impulse curve rather than the back side of the curve on which all the other literature focuses.
As a side note, I have about 20 years of experience in pro audio, which is why I have a Smaart rig in the first place. Now the acoustics of large spaces are very different from home theater, but physics is physics. It strikes me that virtually ALL pro audio speakers and subwoofers are bass-reflex designs and I have designed, built, and experienced many large venue sound systems that are capable of generating "tactile sound" at overall sound levels that are not ridiculous. That is to say around 95dB. Applying my experience with large venue sound to home theater is a large part of why in hind sight I think I may have made a mistake going with acoustic suspension speakers and subwoofer.
So what are your thoughts? Am I on the right path in thinking that in going full acoustic suspension with the goal of superior "fidelity" I've sacrificed the "dynamic" capabilities required to generate tactile sound impulses that kick the chest and vibrate the clothes? Or is there something else going on?