Ok... update: 11:06 PM
The subs have been moved by hand upstairs, and into the media room.
I enlisted the help of my friend who is pretty strong. We managed to carry them upstairs by hand, then I was able to scoot them around the media room myself.
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First listening impressions:
These things are massive and have a powerful presence in the room... both audibly and visibly. They are definitely difficult to move, but they aren't as unmanageable or as scary as I thought.
Bear in mind, I've never owned a subwoofer, or even played with one. So my 1st experience with home subwoofers is tonight with dual Monolith 16 Ultras.
Take that for what you will.
At first, I was playing around with some movie scenes in Saving Private Ryan 4k Bluray, and I was honestly underwhelmed. The bass barely seemed better than my original Polk tower speakers, and I began fearing the worst. Were these subs were defective? Had I set up some connection wrong? Perhaps I just had an unrealistic expectation for what a subwoofer should do?
After verifying all the connections were solid, and verifying the subs were indeed playing bass, I re-checked all the system settings.
I realized, the Denon receiver was mistakenly set to some other kind of simulated surround mode instead of the official "Atmos" mode. Once I replayed the same scenes on Atmos, the subs became "switched on" and immediately more violent. So clearly Atmos mode was extracting much more bass output from the same scene.
The first takeaway then is that the setup of these things is pretty critical. There may be many more enhancements that I can improve upon.
I have the dial on the subs set to 0DB, Extended Mode, and crossover to "off" (since the Denon is handling it). I tried the Denon digital crossover set to 80hz and 100hz... I am not sure which is better.
I demoed various scenes, and experimented with different volume levels, from -20db, -10 DB, -5 DB, and 0 DB on the Denon x4500h, as well as crossovers from 80hz to 100hz.
When I approached 0 DB on the Denon in Atmos mode, with the cross-over set to 100hz, and the sound was incredible: Gunshots and explosions were literally visceral. The German tank rumbling through the street towards the Americans caused my entire floor to rumble with some palpable amplitude. The engine and vibration from the tank rolling forward vibrated the room violently.
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When the Germans fired the 20mm cannon rounds at the Americas, the concussions from the 20mm cannon shots hit me in the chest and lower back more than any commercial theater in my lifetime. It was actually a "wince-worthy" effect.
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So my second takeaway is that these subs have way more output than I can probably safely use. (I didn't even get into the positive ranges yet...)
I did not dare go beyond -0 DB on the Denon, because my wife came in yelling that all the ceiling can-lights and door hinges in the rooms downstairs were vibrating 4 rooms away. So at this point, I am not sure what effect these subs may have on the structure of the house itself.
My final takeaway is that I observed that by transferring all the heavy lifting of the bass to these subwoofers, it seems that the sound has improved from my other speakers.
I cannot say for sure if this is the case, but that was my impression. The entire system now SEEMS to have a much cleaner/crisper sound. This was something that I was not expecting.
One fear that I had was that by eliminating the deep bass from my 7 speakers, including my 2 tower speakers in the rear, that the bass might actually seem more localized and less enveloping. Thankfully, this did not seem to be the case. The bass was very omnipresent in the room.
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If you have any tips for extracting better sound output, I am open to tweaks/ideas/knowledge.
I do feel like the room itself needs some bass traps and acoustic panels. That was my 1st impression, never having owned subwoofers before in my life.