room setup suggesion needed

A square room is the worst possible ratio. It leads to more standing waves than other rectangular options. There is an ideal ratio. Of length, width & height. Not sure what would happened if you setup the center in a corner. This may be interesting. I do not think a separation of over 10 feet can help. 8-10 for me is ideal. You need mid-bass coupling. You have great gear. I’m sure it sounds amazing. 

@ssg308 Wrote:

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

According to JBL engineer Greg Timbers, 14’’ off the floor is good. His home speaker woofer designs are around 12’’ to 14’’ off the floor. See JBL Everest one, two and the 250TI, the L250, and L300, see here. Flush mounting the speakers in the wall and about 3’ off the floor is best, maybe not always practical see here. I would say raising the speakers about 3’ off the floor takes the floor out of the equation, now its just the four walls and ceiling to deal with. For what its worth. I started with with 4’’ from the floor to the bottom of the woofer frame I’m content with 14.5’’. For your information, my speakers were designed for studio control rooms for mixing and mastering so if there a little above ear level it will not matter as the sound remains the same see here. With all the talk about bass and subwoofers, I like the way my speakers pressurize every square inch of the room, its a visceral feeling as well as eargasmic just like a live event. 😎

Mike

@erik_squires + 1

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

Interesting and informative thread.

@ssg308 Wrote:

@ditusa My speakers are 38" tall she horns are already on exactly same level as ears, so I can skip rising them. 

Another reason for raising the speakers off the floor is woofer floor bounce which can also effect the upper and lower midrange. See page four in the article here. For what its worth, JBL made a speaker with a concrete base; notice the woofer height about 12'' or more off the floor in the pic see here.😎

Mike

@erik_squires Wrote:

The truth is it's often a matter of money and space that determines what we use.  EQ's are relatively inexpensive, and easy to hide.

By golly gee, I agree! 😁

@mijostyn

Let me rephrase. I find your attitude confrontational and ill informed and I don’t need to participate in your argument as a result. Good day.

@erik_squires I'm not playing Erik. The only people who believe in bass traps are the people who sell them. My only motive is to keep people from wasting their money. Measuring and listening to bass is very tricky as it depends on exactly where you are in the room even with distributed subwoofer system. Several inches can produce a noticeable change in bass quality and a microphone is no different than your ear. The so called theory behind bass traps is the material they are made of absorbs bass energy, at locations where standing waves are likely, turning it into heat. It is a perversion of the reason we stuff speaker enclosures full of fiberglass or polyfill. Except in side s speaker enclosure the changes in pressure are at least a magnitude greater, if not two, than what you have in a room.  

That’s a HUGE 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.

@ssg308 got it. Always learning.

@mijostyn - I decline to play with you anymore. I’ve shared my beliefs based on measurements and hands on experience, which I believe is all backed up by research which you are best left to your own devices to find.

@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. 

Square rooms are tougher, acoustically. Consider the possibility of working a corner as the "center" of a stereo pair (as well as moving the speakers out from the "front" wall). Because you’ve referred to "rehearsal" space several times, I’m assuming you are playing instruments in the room with or without the hi-fi accompanying.

Jim Smith’s book isn’t a bad place to start. Measurements are good but only as a starting point.

I’ve had the same core components for a while, moved across the country, different room, different layout. Huge difference in sound (the current room sounds better than the old one).

I don’t use a ton of acoustic treatment, mainly bass traps. Sonics are good, not only at the "sweet spot" but in seating pretty close to the back wall (which is filled with LPs).

I’m no guru, just a longtime hobbyist.

PS: I DSP'd my subwoofers, which do not run through the same circuit as my main loudspeakers (horn type, which solves some issues and creates other issues). 

@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.

@erik_squires Not my EQ Erik. Retail is now $15,000. Eq will not smooth out the nodes. It will flatten the frequency response at any given location in the room at the expense of a lot of power. Can you tell me what an 8 foot tall bass trap is going to do with a 32 foot wavelength? 

Low frequency sound waves are extremely powerful. 20 Hz at a very reasonable 80 dB will cause your entire house including the garage to buzz and rattle. Try trapping that. 

@mijostyn  - I don't think it's an either or situation.  Bass traps help make EQ's more effective.  You can certainly get excellent results in cutting bass nodes with an EQ alone, but traps may help smooth out the bass in more areas on the room than just one, as well as make it possible to fix nulls somewhat better than with an EQ alone. 

The truth is it's often a matter of money and space that determines what we use.  EQ's are relatively inexpensive, and easy to hide.

I am the lowest budget member here and I too benefit from subs, the cheapest you can buy. The depth of the soundstage just isn't there without the low end, the low end from a separate driver. 

@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.

@ssg308 What you have is too much mid bass and not much really low bass. Very few speakers do much below 40 Hz particularly ported designs. You have a more complicated problem because your 15" driver is really a mid woofer. It crosses to the horn at 700 Hz which means it carries a significant portion of the midrange. You really do not want it doing very low bass because that would distort everything else it is doing. JBL needed to use a big efficient 15" midrange driver to keep up with the horn. It was not designed to do really low bass and the specs are very misleading. Ideally you would cross over to subwoofers at around 80 Hz which would clean up your midrange and pass the signal to drivers specifically designed to run down to 20 Hz flat. In my case I used 12" drivers for packaging reasons. I would have used 15" drivers but the size of the enclosures needed to house them would have been prohibitive. I use 8 drivers not to blow everyone away or impress the neighbors, but to form a linear array to match the radiation pattern of my main speakers. For people with point source systems like yours two subs, in your case at least 15", will suffice. You have to hear a system that is capable play low C on a pipe organ. It is a religious experience. 20 Hz is barely audible but boy can you feel it. 

I assume you have been to a large concert or two. The game is recreating that visceral experience in your home. Large venues breath at low frequencies. You know you are in a large space even with eyes closed. A good live recording of a stadium concert should feel the same way. 

I agree with everything @erik_squires says except I am not so impressed with bass traps, digital EQ is way more effective. 

Anyone who thinks they know anything about how their speakers sound in a room because of the specs is probably mistaken.  The room changes everything and measurements are key.

The ability to limit the bass in main speakers and move subs to ideal locations can be life changing, as are bass traps and sub EQ.

@ssg308, bass boom does not come from speakers or subwoofers. Bass boom is a product of room distortion see here.

Mike

@ssg308, quality, properly set up subs will not add "boom". They will not only add more detail to the lower frequencies but will enhance the sound at higher frequencies as well. You will not be able to to localize the sound from the subs, it will be a part of the soundstage.

 I have also had success taming bloated bass by closely adhering to the 1/3rds rule. Speakers moved out from the front wall at 1/3rd of the total room length and the listening position 1/3rd of the way from the back wall. Tweaking the distances from there. 

@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

@ssg308 Your speaker's frequency response is rated at one meter. What they do in a 30 foot room is TOTALLY different, not to mention that you need at least an additional 10 dB of gain to get realistic bass levels. You can only do this with 2 15" subwoofers or more in your room. I use 8 12" subwoofers in a 16 X 30 foot room. Each one gets 1300 watts.

As for as your sources are concerned you should have a better DAC, a Bricasti Design M3 would be perfect. Your turntable is not the greatest, but your tonearm and cartridge do not belong in the same room as your amp, preamp and speakers. You do not have to spend big money either. Get a Thorens TD 1600 and put a Soundsmith Voice in it. It will blow your mind. 

@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 ?

@ssg308 Wrote:

@ditusa so what does rising speakers off the ground,

Rising the speakers off the floor puts the horn at ear height. Decoupling the speakers from the floor prevents sound transmission from the speakers entering into the floor and floor vibrations entering into the speakers (it’s a two way street).

and if I bolt the frame to the wall would it do the same effect ?

What is important is to break the sound transmission from the speakers and the structure. See here. 😎

Mike

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

@ssg308 Wrote:

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

Ok.

The JBL 4367's are great speakers! See my system page, left speaker, I raised 9'' off the floor (the speakers weight 275 lbs each and are 36'' tall, 39'' wide, 20'' deep). I also decoupled the speakers, from the floor with concrete and lead It took two people to put the speaker on the blocks. Raising and decoupling the speakers from the floor improved the sound quality in my system and the cost was low. For more details see here. JBL speaker stands see here.😎

Mike

@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.

Honestly system sounds really good, but better is enemy of good so is there anything I can do better or is there anything that I’m doing wrong ?

- Unless i missed it, i don’t see any indication of a subwoofer. So, that’s a couple of octaves of music (that the artist intended!) that you never heard yet.

- This is the kind of lumpalicious your room would look like (height assumed since you don’t mention it)...Depending on where you sat, depending on where your speakers sat, sbir, etc, there could be some lousy things happening to the sound (that the ears may have just gotten "used" to). There are threads here with material that covers what you could do, if such lousy things are going on. For example, the subwoofer, if implemented correctly is also a crucial "room treatment" device (it can fix things that conventional treatments can’t fix or the quantity becomes impractical, etc.) Have you ever measured your room? On a positive note, the fact that you have a big room is a good thing...lot of problems become easier to fix (big room guys = smaller problems, small room guys = bigger problems).

@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 

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

@mijostyn 

and what would be yours suggestion for the upgrade ?

It is impossible for me to comment without seeing and hearing the situation. I can say that your system deserves better sources.

@ssg308 Wrote:

room setup suggesion needed

I would raise the JBL speakers about 8’’ off the floor, with a slight toe in, see here. 😎

Mike

Decades ago my loft space was a bit larger and more rectangle. I was using the bands Altec A7's, a similar two way bass reflex / horn.

An acquaintance recording Engineer had just sold me his Octavium subwoofer. After showing me how to position a subwoofer in any room he positioned speakers. Approximately 12' apart, 5' from the front wall and possibly 8" from the side walls and very little toe in. With the listening position about 10-15' with a great deal of room behind. He taped the floor with their locations. I never did exact measurements, sorry.

This was my first experience with stereo and despite scratchy LP's and FM, in hindsight this was by far my favorite in home presentation. Having all that room to myself was the bomb. 

Unlike the subwoofer, he could only generally explain what to listen for when locating speakers. He warned that room uniqueness and the vast differences of speakers would be accomplished by a novice with patient experimentation and using a mirror to determine the sidewall first reflection.

Despite all the rooms and speakers in my experience I'm certain I suck at speaker positioning. I'd guess you have exactly the right type of speaker for that size room. Good luck with your setup.    

I guess it depends. But if you start with a recommended configuration, I would say a small spaces are much harder. You have wall reflections on all sides (including behind the listeners head) to worry about… bass reinforcement you may not be able to fix, except by tube traps, lack of abolition to get enough space behind the speakers… etc.

@ghdprentice and I would add the bigger the space, the harder to get it right? Not sure since I have no experience with bigger spaces.

All speakers are different, all rooms and furnishings are different, as are components driving the speakers. What you get is a nearly infinite variability. Hence there are some standard starting positions for each of the position variables. The listening triangles cannot be too large or the stereo effect begins to disappear, bass reinforcement from distance from back and side walls, and how direct the tweeters point at your ears effects the soundstage profoundly as tweeters are very directional with sound dropping off, off axis. Slow methodical experimentation required.

grislybutter

Interesting, that's far more than subtle acoustic change resulting from a relatively small physical change

@elliottbnewcombjr I had a very interesting phenomenon, I placed 2 floorstanding speakers next to my standmounts, about 5 inches on the outside. The sound of the standmounts has completely transformed, it helped the speakers disappear and made the different elements feel more focused, "sourced".

One tool that's super easy ot use is the AM Acoustics room mode simulator.  Plug in your room dimensions and it will help you avoid the worst trouble spots for speakers and listening location.

Large Room for Small Audience is Difficult (you or you and a mate/friend perhaps)

Square Rooms are Problematic

.......................................

My suggestion, use the room differently, sub-divide by use, not necessarily walls, although tall folding screens might work): perhaps move the music area 14 feet from a wall, use the 14 x 30’ area portion for: (semi-private office, music library, conversational seating, small video, dining, a combo .........)

now the music space is 16’ x 30’.

I would first try:

speakers on short wall, a few feet from sides (one side a wall, other side a tall enough bookcase (lps?) to 'be a wall' to the speaker

far in front of rear wall. now rear ports not muddying initial reflections, and you will get a deeper sound-stage.

Speakers: Wheels: Alternate Locations

Toe-In Alternates: Stereo and Video

To read photo captions, and/or view larger photos (any virtual system), top bar, ’TOGGLE FULLSCREEN’

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

As @newfzx7 mentioned, you will get less bass reinforcement for all speaker types by moving them father away from the back wall, but the key is finding the position where the speakers sound most balanced and the bass blends best into the sonic picture.  Obviously playing music with more bass content will be more helpful in readily hearing the differences in placement with this aspect, but do also play music with big recorded 3D space so you can also better assess critical imaging and soundstage differences as well. 

I have / had  sealed, rear ported, front ported and bottom ported "box" speakers. All would decrease in bass as they are moved from the wall boundaries. Trying different distances is key to finding the right balance between bass output and sound stage depth. I prefer my speakers far out into the room but have solved any bass issues with a couple of subwoofers.

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

I adjust and move my speakers 2-3 times a week. Different recordings benefit from different setups, so I don’t think there is one right way. Also, am I in the mood for a wide soundstage or feeling close to the singer, with the instruments in the background?

I play with 5 to 7 feet apart 2-3 feet from back wall, toe-in enough that I can see the outside of the speaker walls. Your room size, speakers are vastly different though.

Now setting speakers farther off the wall, what does it do ?

for rear-ported speakers it would reduce the bass, as far as I know

move the speakers around to different locations in the room and judge for yourself what is best

Experimentation is key, and the good news is it’s free.  As @ghdprentice recommended I’d pull the speakers out further from the back wall and closer together, and try decreasing the toe in of the speakers so they fire just to the outsides of your shoulders.  Doing this you may find the soundstage expands and has better width/depth and the speakers may also disappear better as a sound source.  You will lose some wall reinforcement so bass energy will likely decrease a bit but may actually be better balanced so give it some time for your ears to settle in with it.  Really just play with it and let your ears be your guide, but I think you’ve got some significant upside potential here with better positioning.  Have fun!