Down-firing subs and downstairs neighbors

Hello Cleaneduphippy
I don't know anything about the innards of the new house (or the neighbors). Actually I have a sub already, a basic HT Velodyne I'm thinking of replacing. I'll see how it works in the new place before investing in a better one.

I use the sub now in a bi-amping arrangement with a NAD integrated (NAD only gets signal above 80hz). I like this arrangement--that's why I'm keen on having a sub. Don't care too much about very low bass.

Abarnett, I live in an upstairs duplex with two downfiring MJ subs. So far it has been good with no complaints. I did do the Auralex with bass traps, sound absobtion panels and diffusion (check out Guitar Center for the roominator kit). The livingroom is w/w carpets which helps insulate the floor. I am in the process of attatching a plinth with about an 1.5inch gap with the subs and some high quality spikes underneath (check Eden Sound for custom fits).

This is a must is get the Granite Audio Super Bass cd from Quuest for Sound. There are test tones from 10 to 99hz for 10 seconds which helps finding the noisy vibrations and rattles in the room and throughout the apartment. Use blu tak or rope caulk to calm everything down. Sometimes the bass might not be excessive but noisy vibrations can be harmful to the music but more disturbing to the neighbor downstairs.

Ofcourse being polite about the bass is just being a good neighbor. If company is downstairs, tone it down a bit. When the place is all yours, I am sure you can figure that out. As for me, I pretty much know the schedule downstairs and take it from there.

Good luck.

Great true "Audiogon" story about this very subject. A couple of years ago I was selling a Parasound C2 and I got an email from someone asking if I would ship to France. I had never done that before, but said I would look into it. After researching the process I found that shipping to any EU nation was a pain in the ___ but as luck would have it my wife and I were taking our first trip to Paris and could he pick it up there? Well turned out he lived in Paris but we didn't do the deal (customs at CDG would have been a nightmare with a piece of complicated electronics) but.... He was very appeciative of the effort and invited my wife and I to dinner while we were in Paris. I thanked him, but thought his offer was a simple courtesy.

To jump foward, when we arrived in Paris there was a bottle of Champagne and an offer of dinner. We of course accepted, had a great dinner and got to see Eric's system. They lived in an apartment, of course (which was amazing btw, on the Seine, not near it but on it, with a wall of windows looking out on the river framing the Eiffel Tower). He had commercial sub from a movie house, and I asked how his neighbors liked that. He had the only response that would work in that situation: The guy below him was completely deaf and could did not care. So if you look for a place with an old deaf guy below you, you can get any sub you like!!!

I own the building.

But truthfully, to keep good tenants I have to watch it. They've had loud parties late into the night and i'm cool with it, so if I have a loud moment its cool too. Plus they take trips often!

Also, an old wooden house is a musical instrument. Sound will permeate every crevice in the floors.

Best to have your own detached single family house.

Yeah, it doesn't really matter whether the sub is down-firing or not - as may have been mentioned here by others. You issue is that the subwoofers soundwaves are going to couple with the floor and walls and such, and translate out to your neighbors. Yes, some of the sound will actually pass through the materials and into the spaces as well.
Putting more insulation will help a tad bit for bass, but not enough, as bass waves are long - and you really need to put serious mass between you and any other zones, and/or "de-couple" the boundaries!
You could build almost a complete floating floor over your existing one, which will help quite a bit in keeping the bass down bellow significantly. However, the walls still attach the floor, which should have issolated walls to be more completely effective in your effort - and there are alternatives here, depending on how involved you want to, and CAN get.
If it were me, and I lived in an apartment, I would simply be satisfied with some larger bookshelves that played down to the high 40hz range, AND FORGET ABOUT IT!
Really, it's all about quality anyway. Small speakers do well in small spaces - set up well. If you had a large space that would support such a beast, then fine. You live with neighbors all around. So I would be happy simply considering them, and just enjoying what I have, personally. But, you might be coming from a different place.
I say this, as I really used to enjoy going over to a friends house and listening to music and movies on his really nice monitor system, 2 channel! (sans the sub).
Perhaps you could do some reasearch on sound issolation on the cheap? Hummmmmm....
How about this - you go on craigs list, and look for some office particians that someone is giving away for free, cause they're moving buildings or business's or something! Then, you use those as your floating floor base, as well as side walls!!!! That would work! Lol- you might have to firm up the pannels in places, like the floor. But hey!..they'd be free!...
It's a thought
good luck