[nodiak]

No problem HiFiJake, can you tell I'm a little tense about all this?!  Sorry if I read you wrong, I don't usually worry about the battles. I'm a little worn out lately.
There's so many ideas to try and so little time to enjoy the music that the equipment searches and now room treatment experiments get frustrating. Winter season is when I get into audio, and honestly I'm pretty tired of forever working on the system, other things to do. Need the music for relaxing.

Hey Bryan, thanks for your help and guidance in this. Last night I had a little concert with Allman Brothers Fillmore Concerts. Everything was much much more 3D and flesh and bones. What seems to be going on is the ambience from reflections used to be what made the music seem alive. Now without that going on so much the weight and form of the musicians, instruments, stage effects, and outpouring music on the recording are uncovered and fill up my room.
Some 1st reflection absorbers, ceiling and rear wall diffusion and I should be good. Can make any improvements later.

Russell, I'm not against trying drapes, but those would cost me over $500 for the size I need. May take a trip to the thrift store.

Don
   
 

[Ethan Winer]

Bryan,

> It's a delicate balancing act to get the room to pressurize so you feel the bass instead of just hearing it but not have it so out of control that you have resonance and decay time issues - hence the bass absorbers.  Pressurize the room, feel the bass, control the resonances and decay.  That gives you the 'slam in the chest' feel of the bottom end. <

I'm confused by your comments. Your use of the word "pressurize" implies that a room is like a bicycle pump where the air pressure increases as sound comes out of the speakers. Okay, I suppose the air pressure really does change by some infinitesimal amount. But that's not how I think about this stuff. Indeed, we all know that opening a door that's in a corner helps the bass response because an opening is like an absorber - by definition! That is, 1 Sabin is defined as the same amount of absorption as you'd get from an opening of 1 square foot.

So to me an ideal room would have open doors in every corner, with the doors leading to outside rather to other rooms where the sound could bounce back in. In that case there's be very little pressure build-up, yet the bass would be fuller, and cleaner, and flatter, and have less ringing than with the doors shut. And you'd feel the slam in your chest more because of all the above.

If I'm missing something I'm sure you'll set me straight!

--Ethan

[ctviggen]

I think the overall pressurization wouldn't change, as when a bass driver pushes air toward the listener, it pulls air from somewhere else in the room (unless the bass driver is in a sealed cabinet, but the net effect is still zero). 

[youngho]

I wonder if Bryan may be talking about room/cabin gain below the room/cabin's lowest resonant frequency, which is altered by perforations or "holes" in the boundary, just as bass response when playing music in the car seems to diminish when you open a window.

[Russell Dawkins]

Winter season is when I get into audio, and honestly I'm pretty tired of forever working on the system, other things to do. Need the music for relaxing.
Don

Don, considering that time is an issue, if I were you I would find some way of creating the curtain acoustic temporarily to find out if it's even worth going to the trouble and expense of doing it right.

I would get a couple of big sleeping bags or thick comforters and just place them against the wall, held against it by broomsticks or something. Near rather than flat against the wall would be better if you can arrange that.

Then listen to the result and if it takes you in the right direction, acoustically, then you have some justification in putting your money and time into curtains as a solution.

[bpape]

Ethan.

Well, if you had a door in every corner, you'd need a BEAST sub to get that smack in the chest feel of a good deep tight sub.  My ContraBass can pull it off - even totally outside - because that's what it's designed for.  Most subs wont't do 16hz at 114db anechoic.

You're also assuming that the doors open to the great outdoors.  In reality, it's just letting sound out and coming back in off a different surface somewhere else in the house that's going to cancel who knows where, how much, etc.

Having a room sealed up gives IMO more of a tactile sense of the bottom end.  In this case, the opening is centered on the rear wall so there will be a benefit of not getting that nasty null off the back wall. 

Bryan

[nodiak]

Russell, agree and exactly my plan.
We're on the 2nd floor and this window has a nice view (for being in a town). We can see the forested hills, skyscape, incoming weather, and townscape. So it's nice to look out. Even at night the occassional plane slowly goes by in it's landing approach. Curtains would only get used by me for audio moods, and maybe a small bit of insulation overnite.
Don 

[Ethan Winer]

Bryan,

> Well, if you had a door in every corner, you'd need a BEAST sub to get that smack in the chest feel of a good deep tight sub. <

I have a BEAST sub.

> You're also assuming that the doors open to the great outdoors. <

I didn't assume that. I just said in an ideal room.

But my question still remains about the use of the word "pressurize" in this context. Why pressurize rather than simply SPL?

--Ethan

My sub:

[bpape]

If you're up for a test, try this.

Take your sub outside.  Sit 1m from it and set it to 90db at 1m and play a 30Hz tone.  Then go inside and put it in a sealed room with the door closed, sit 1m from it, set to 90db at 1m and play 30Hz.  If it was just SPL you wouldn't hear or feel any difference.  I'll bet you a beer that you do 

Then open the door and see where it falls in between the 2 experiences.   

If you want to look at it your way purely as an SPL thing, coupling the sub output to the room also gives a gain in efficiency overall.  When you're doing the above experiment, look at the power it takes to generate the 90db in the 3 different situations.  This allows the sub amp to operate with less strain to generate the same output in-room - leading to less distortion, less heat, and more headroom for dynamics.

If I have a sub with a 300W amp and outside it takes 100W to do the 90db, and the room gives me even 6db of gain, I'll take it.  Having the door open or closed will rob you of at least a couple db of that 6 - or more appropriately, the closed door will give you a couple db more.  To get that 2db back, I'll need approx 167% of the power I'd need if I closed off the room. 


Bryan

[Russell Dawkins]

nodiak,
I'm guessing the window doesn't open but if it did and the panes pivoted rather than slid, it would make a the ultimate bass "absorber" (more like black hole) and would give you a taste of that excellent, in my books, outdoor sound.
I think it's worth mentioning again, for those who have the luxury of being able to try this, that it really is instructive to assemble your system outdoors sometime during your summer (could be now in Aus and Hawaii) and hear what your room is adding to the sound coming out of your speakers. It isn't a subtle thing and sometimes it ain't pretty.

[nodiak]

Russell, that would be really great to have windows like that ! I'd loved to have a large screened porch for summer listening. I moved and my listening room shrank from 8640 ft3 to 2285 ft3. Not even similar sound using same equipment. This room treatment is helping alot, but I don't pretend to ever have the expansive openness of the large room.
Don