room setup suggesion needed

@ghdprentice  I heard before theory of crossing beams behind listening point, and quite frankly I don't understand theory of it, but in the same time I never had setup without speakers toed in. Now setting speakers farther off the wall, what does it do ?

@soix @grislybutter How important is back wall setback for the front ported speakers ? 

@m-db  well they are bit undersized according to QSF calculation how ever they are the biggest I was willing to deal with, still 157lb is not a Mickey Mouse 

@mijostyn 

and what would be yours suggestion for the upgrade ?

@ditusa ok I get the concept but execution could be tricky since they weight 157 lb each,

@deep_333 

Ok let's clarify some things first, as far as I see you speak numbers and diagrams language so it will be easy for both of us.

You are one of us who use subwoofers, so let's do some logical calculations and see if it makes sense.

1. human can hear from 20Hz to 20KHz but in reality adult person will loose some of the top hearing so maybe 15-17KHz tops.

2. Best subwoofers operating  from 30 Hz to 50Hz, anything less like 25Hz and below will not be sound it will be more like pulse.

3. JBL 4367 speakers  delivering sound from 30Hz to 40KHz

So now, how is your theory of missing subwoofer works exactly when my speakers match frequency of the best woofers out there?

The idea of HIFI stereo was to replicate sound recorded or performed as true as possible and as realistic as the sound itself, so by definition adding components to the system that emitting sounds below hearing range, just to create boom effect makes no sense in my book. When you go to cameral quartet concert there is no amplifiers or speakers you sit and you listen people playing instruments, now those instruments recorded you replicating home on your HIFI it should sound exactly the same, there is no jackhammers under concert floor to create vibrations they do not exist just for the thrill of the spectators.

Now coming to the sound wave shown on your diagram, can you drop the ceiling another foot down to 8' I would love to see what will happen with the bounce of sound after the ceiling was adjusted.

What will happen with 38Hz point, if it will bounce  before 7.25 mark or after.

@ditusa  so what does rising speakers off the ground, and if I bolt the frame to the wall would it do the same effect ?

@ditusa My speakers are 38" tall she horns are already on exactly same level as ears, so I can skip rising them. Now creating dampening platform that would separate speaker from the structure can be tricky but I can see logic behind it, it seam to be cuter to subwoofer idea where people deliberately dumping huge boom in to the floor in order to cheat the ears and other senses.

I need to do some thinking about the heavy pads. Would it be ok to set it up on 10" steel injection mold ?

@mijostyn  here is the answer, like always it lays in numbers, 8 12" mathematically 

should do better job than 2 25" but in fact they don't there fore subwoofer is backing up the system with sonic boom. I don't have that problem in a fact I need to move my speakers off the wall farther to control my overwhelming bass.

As far as the sources, my TT is just something I like to play with but I'm not using it as the main source. DAC on the other hand is what I need to develop a bit better and I'm looking for alternative to what I have. I was looking in to the streamers/servers and as of now I'm not sure if I like the idea, sending digital signal from any computer shouldn't  be a issue, it's only matter of software and file quality, DAC on the other hand can do big difference so I definitely take your advise and look in to Bricasti Design M3

@mijostyn 

all great points and I agree with most of it as long as we talking about that low C on the pipe and not about death metal or grind core that also have to sound great!

the way I see it, is that there are variable in whole equation and rather you have too big room too small speakers too weak amp or any other not correct for conditions of the room combinations of above elements you won't be satisfied.

Now if system works great as is, sounds fantastic and than you take away subwoofers and its all dramatic, guess what you don't have speakers, if my issue is the fact that some frequencies are overlapping and I have to sit and pay attention when they overlapping because my ears are not the freshest, o well so be it.

Ive been listen stereo way before subwoofers were invented and I'm sure they have application somewhere, but not in my system, even at the price of not having 100% sonically correct sound.

and yes I agree manipulation of digital signal by software before decoding is far more superior than any other filters.

@mijostyn you are very correct 80 db at 25Hz from generator at my place is definitely loosing screws and retracting nails from lumber.

Again you are right, if anything than low headroom is my biggest challenge of them all. I do believe I have power and speakers to amplified that room with no problems, however finding perfect rehearsing position its becoming an issue.

I’m leaning to your opinion related to 8ft ceiling.

@grislybutter budget has nothing to do with the acoustics, its simple rules of proportions. Either you have it or not. How much you paid for it or how old it is, is irrelevant.

It is very simple, every concert hall has specific size shape and proportions, stage to audience, for instance full set philharmonic orchestras can fill room in ratio 3/1 where 3 is audience and 1 is orchestra. Now if you take quartet or duo they can do ratio 20/1 but in order to keep those proportions the adjusting size of the rehearsal room. 

@whart  point taken,  I'm planing to do some new arrangements in the room over the weekend I wonder where it will get me.  I need to move point of impact of 38Hz wave about 2ft forward, the only thing I can't do anything about is ceiling height. 

I build great sounding rooms before but never for speakers that size.

@ditusa I measured my speakers and I need to lift them about 5" to get it to 12" formula