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I'm really crammed for space, the only way I can get my JBLs spaced evenly on either side of the table is to have them facing each other.

Is that Sacrelige? Will it compromise the quality of my sound?

The only other option I have is to put one a few feet away near the other side of the wall.

Any help would be greatly appreciated.

Comments

KurtFoster Sat, 11/30/2002 - 18:25

Yes, yes it is sacrilege. Sorry to be soooo harsh, but it seems your putting the cart before the horse or rather the horse behind the cart! The first thing you want to do is place your speakers. Everything else in the set up should be to accommodate the speaker placement. Speakers should be set up to form an equal triangle, with the same distance between the speakers and you. That is, if the speakers are 4 feet apart each speaker should be four feet from your head so it forms an equal triangle. No ifs, ands or buts! Set in stone, period! I Hate to be the bearer of bad news but it sounds as if you're going to need to completely rearrange the room so that you can get those speakers where they belong. Try to have fun! ........Fats :w:
edited once for spelling

KurtFoster Sun, 12/01/2002 - 08:30

Four feet would be better but if three is all you've got that will have to work. It's hard to hear stereo separation at less than four feet apart and at three feet sometimes the sound from the tweets and the woofs haven't had enough distance to come together. If you can get four feet, that would be better... but if you have to do three that is certainly better than them being on the sides pointing at each other! ............ Fats

anonymous Sat, 12/28/2002 - 06:37

Angling them now.

Should I have them sitting on some type of padding? The guy at Guitar center told me if I sat them on some foam, I would get more bass because the vibrations wouldn't go through the table or something. However, I think he was just trying to sell me the extra foam... which I didn't buy.

audiowkstation Sat, 12/28/2002 - 07:15

Fats has a good point but also try this:

One of them you will like better.

Fist of all I like all drivers on the horizonal plane. This means laying them on their side. Both woofer and tweeter will now be at ear level.

Second, thie has been some debate on this but MY personal preference with the speakers on their side is to position them with the tweeters on the inside of the image. Reason for that is that the tweeters are slightly closer to you and in the highs is where you get all the imaginig. Putting the tweeters on the outside means the delicate tweeter tones must travel through the woofer wave. Also high frequencies reflect off side walls, tweeters on the inside of the image minimalizes this reflection.

3rd, I like the speakers to fire slightly past me. IF you hold both arms straight out (side to side) , I like them firing at my elbows and if you have some distance.. even slightly more toward your wrist. The reason for this is that the highest freqencies imminate from the very center of the tweeters only in a straight line. Many manufactures tweak their crossovers so at near field at 12K hZ point source (meaning dead ahead of the tweeter beam, right in front, the 12K hZ is about 4dB up. This is industry standard I am afraid so to get truly a flatter freqency response, many loudspeakers tend to balance better at 15 degrees off axis. Cedats Tannoys that are coax compression drivers imbedded onto the pole piece of the woofer does not go by this rule but a 2 way and even some 3 ways do.

It will not hurt to implement these factors. Use familiar music. Give each test about an hour to get use to it. try it at all volume levels.

About the foam.

2 schools of thought:

Isolation
Ridged coupling.

ISO:
The foam will keep the cabinet resonances from exciting the unit the speakers are mounted on. This is ok...to a point. I would experment with towels first to see if the vibration is reduced to the stand they are on. If so, this will keep the stand from making noise that can deteriorate from the overal sound.

Ridged

This technique offers outstanding benifits of coupling the speaker to the stand. The stand must be acoustically dead. A ceramic collum filled with sand is the cheap way out. The the bottom of the stand has 4 spikes on it that literally sticks either into the carped to the cement or wood, or directly to the wood. (Floor) If you have a prized wood floor, get a square of wood cut (your choice) for the stand spikes to press into.

This is called Mass coupling.

The advantage is the entire vibrations are now transmitted to a dead surface and stopped before they can cause havok.

Sorry so long but the art of loudspeaker placement is very advanced. On my monitors, If one loudspeaker is 1/4 of an inch closer to the rear wall, I can hear it in the imaging. Do your distances in a precison way. Make sure the speakers have no ovstructions around the sides or anything to block the pattern. Make sure the left and right side of your room is symentrical.

I hope you can implement some of these things and report back which way it works best for you.

The Cedar method is the quickest way to begin tweaking. It will get you on the right path.

Just experiment with this. You will be amazed what 1 inch of movement can do for the sound.

Doublehelix Sat, 12/28/2002 - 08:01

Bill...I always find your posts extremely useful and I even find myself copying some of your comments into Word, printing them, and them gluing them onto index cards! You da man!!!

But come one here...1/4 inch??? One inch I might be able to buy, but 1/4"??? If this is true, you have better ears than I :c: (which goes without saying anyway, I guess...)

audiowkstation Sat, 12/28/2002 - 08:21

...I should have said an 1/8th actually but I left it at 1/4 since I do not want to appear to be messing with peoples heads.

Actually yes.

Look at this:
If the sound arrives at my ears of a 10kZ tone that is mixed for mono.

Lets say that sound travels roughly 1250 feet per second and this is 10000 cycles/sec full 0 to 90 to 180 to 270 to 360/0 degrees. Each one!

The length of the 10000hZ wave is 0.125 Feet or lets round that to an inch for the sake of simplicity.

Now, if 1 cycle of 10000 hZ is an inch long and I move the speaker 1/4inch back from absolutely equal distances..(provided your speakers are deadly accurate which mine are) then 1/2th of the top wave which is 90 degrees is behind the other. When you really dial in a set of speakers and you are sensitive to phase as I am, the quarter inch is so audible I have to move my head back and forth and say..damn it is not in phase anymore..then I measure..surely I can find the sweet spot and lock onto it. I measure the distance again and it is off. So I correct it and the problem I am hearing magically goes away and the now 10K hz tone is coming from a knife blade dead in front of me that seems about 5 feet behind the monitor that is in front of me. Just moving a light fixture is audible and I must turn the overhead fan off. It drives me ape shit with all those reflections beating around.

With the right system, with training on what to listen for, with the right acoustics, super matched speakers, yes, phase is in my face. It does annoy me that I cannot move much when listening critically.

I know this sounds like snake oil but this is why I must leave my system on at all times, have controlled voltage, calibrated speaker cables and calibrate the system every day before a session.

Strange as this is, a 0.2dB difference in right to left channel balance moves the center image what appears to be about 5 inches away from center.

Heresy is what it all is.

It becomes a pain in the ass at times. One day I hope to lose this ability..

anonymous Mon, 12/30/2002 - 08:04

Not to throw paper into the fire .. but after all of this placement issue .. you also need to know what you might expect from these .. so, one simple starting point would be to plot the room. To do this you need math: f =1130/(d)x2 .. so frequency = 1130(speed of sound)/(distance)x2 .. frequency = 1130/(21')x2 ... 1130/42=@27hz. This would be the 1st room mode for say a 21' length, the 2nd for that 21' length = 27+27=54hz, the 3rd = 54+54= 108hz, the 4th = 108+108=216hz. Do this up to say the 12th set of calc's.
Now, do the same for the width of the room, and also the height of the room, take these three and plot a curve to see what frequency(s) are close to or the same .. these would be the standing waves you will have problems with .. the less the better, and the lower the initial starting room mode number for each dimension, the better. If you did this for say an 8x8x8 room, you'd quickly see why a square room is a problem.
All this being said, also keep in mind that the numbers will not be exact due to whatever construction was used in the room and whatever else is in the room .. however, it will afford a fair idea of what would be an easier room to record and/or mix in.

Please correct my math guys if I'm off in the numbers above, but I believe it's correct, and certainly the principle is valid, you agree??

Doublehelix Mon, 12/30/2002 - 17:00

This is a bit OT, but related nonetheless...

Was curious if anyone has any opinions of the Auralex "Mopads", which are those foam pads to put underneath of monitors to decouple them from their base. It seems to me that these will defeat the purpose of having the rigid platforms that attach to the floor with spikes.

What is the opinion of the pros on this? Bill?

Gary Gidak Mon, 01/06/2003 - 13:15

To do this you need math: f =1130/(d)x2 .. so frequency = 1130(speed of sound)/(distance)x2 .. frequency = 1130/(21')x2 ... 1130/42=@27hz. This would be the 1st room mode for say a 21' length, the 2nd for that 21' length = 27+27=54hz, the 3rd = 54+54= 108hz, the 4th = 108+108=216hz. Do this up to say the 12th set of calc's.

What if your room is not symmetrical? My control room is 8' tall, and 12' long, but the front six feet of the room is 12' wide, and the rear half of the room is 10' wide. I also have an entryway at the right-rear corner that adds an additional 7'x3'x2.5' to the overall volume of the room. Should each symmetrical portion of the room be configured sepparately - ie: front of room, rear of room, entryway? Sounds like a lovely geometric excursion! :confused:

audiowkstation Mon, 01/06/2003 - 14:56

This is where intuition takes over and math is used to fine tune.

First, Look at the soundwave. How can it get to you unaltered.

Enter:

Near field.

The beauty of near field is that the sound waves entering the ears from the speakers get to you first before they have a chance to get somewhere else. Clear a path to you and your speakers.

Second, enought sheer output in near field will mask the room.

Third, position the speakers so that if the room is involved at all, do so by coupling the enclosures to the floor so that the lowest FQ (if the speakers can get below 35hZ) can make the room move.

Just experiment.

Different frequencies travel at different velocities as well rendering precision math moot.

Use thy ears first.

Alécio Costa Mon, 01/06/2003 - 18:10

Bill, seems I have to get rid of that stupid dead room which is on the right of my sweet spot, right?
One question.. My near field monitors sit over the desk, where I have the 02R some equipment.. I put foam under the monitors.. what would you recommend me? now I feel less bass "intrusion..
I read somehere that in fact you must have the near field 1 meter from every corner, wall.

please, go deeper into this and give us ( me some tips
Thanks
:)
:p

anonymous Wed, 01/08/2003 - 10:13

Hi All,

In lay terms. You do not want to face speakers into each other because "phase cancellation" will happen. Phase Cancellation is when to frequencies collide at the same place and point cancelling out the other. Kind of like what happends in older Mackie consoles. A very thin sound. As far as placement is concerned, your monitors need to be as I think Bill said, at ear level. I have seen some top engineers aim them in just a little. Realy it is what works for you the best and with your room. I will do both depending on the project. The best room design I like is a "live end dead end". This is when you place acoustic foam behind your monitors on the walls and on the other end where the sound is traveling towards has some form of dispersing properties. The sound needs to be moved out of the listening area. Of course this is a whole new topic. The "rubbertex" type foam that is about 3/16" with a sticky back is good to isolate the monitor from the stand. Whew... Good Luck

Mix77

anonymous Wed, 01/08/2003 - 11:01

This is very interesting because I'm always wondering how my NS-10's were (according to their literature) designed for either vertical or horizontal placement, yet my Tannoy literature derides producers who lay their monitors on their sides for line of sight reasons since it produces all kinds of comb-filtering.

What Tannoy was saying was that you sit in front of your monitors and your head is at a fairly fixed level. You *do* move side to side quite a bit, and if your speakers are horizontal, you do a lot of cycling through different comb-filtery spaces. If you're going vertical, the only way to encounter this problem would be to move up and down a lot.

(Go to http://www.tannoy.com and download, say, the Reveal manual for their boilerplate speaker placement tips and tricks plus this technical stuff.)

Also, I have my NS-10's with the tweeters on the outside because it sounded better to me there. There seemed to be little more image to them that way. I'm a little confused about this because with my speakers angled in at me slightly (and tweeters out), the tweeters *are* closer to my ears than the woofer by a couple of inches.

I keep the Reveal Passives vertical.

Whatdya make of this?

best-
.nick

knightfly Wed, 01/08/2003 - 12:00

Bill, you must have some really strange air in Florida - your comment about frequency vs. speed of sound being the first I'd heard, I went looking - here is one of many sites that specify the exact same relationship - note the comment near the bottom;

"It is important to note that the sound speed in air is determined by the air itself. It is not dependent upon the sound amplitude, frequency or wavelength."

http://hyperphysics.phy-astr.gsu.edu/hbase/sound/souspe.html

to use the calculator, enter the temperature in degrees C, then hit the Tab key...

On the subject of speakers on foam or NOT, I think it was KRK who suggested NOT, citing the reason that the woofer excursion can cause the entire cabinet to rock, varying the phase relationship between woof and tweet.

Similarly, since your head tends to move more from side to side than up and down (or should I say, MINE does), it would make more sense to me to have the drivers aligned as Tannoy suggests, (vertically)so that you cause less phase anomalies with lateral head shifts (you would still get the phasing caused by distance variation between left and right speaker, and I concur completely about the 1/8" comment, but with the drivers horizontal you would also get phase changes between drivers on the same speaker, whereas with the drivers in a vertical line, BOTH the drivers in one speaker would shift phase the same direction) (Not the same amount, since phase shift IS frequency dependent)

BTW, there was another calculator I found

http://webphysics.ph.msstate.edu/ccp/15-4d/

that factors in humidity - so, in my studio the speed of sound is about ll35 ft/sec, while yours, Bill, assuming the A/C ever goes on the fritz, will be about 1153 ft/sec (86 degrees, 99% RH) :=)

James, the better your high frequency hearing is, the worse these phasing problems will seem with less head movement since the higher the frequency, the shorter the wavelength and the less distance it takes to effect the same phase shift... Steve

anonymous Wed, 01/08/2003 - 12:32

Hi Nick,

It goes back to knowing your room , your montiors, etc. Every room will produce a different result. I remember when I was at Full Sail (20 years ago and I'm showing my age) they told us if you give 10 guys the same gear and unleash them on a square room you will get 10 different designs, lol. So true. I still have my old NS10M yamays, they look pretty but sound like, well you know. I have been using the Audix Nile and Genelec monitors for the past few years and I like um pretty well. Looking at the 6.2 surround Genelec boyz lately but can't seem to get off the money. Anyhoo, Good Luck!

Mix77

anonymous Mon, 01/13/2003 - 06:13

Styles .. yep this does become an issue when the room has different dimensions .. you can still do some of the math and think about how it may apply as you listen. Certainly a RTA and good EQ will be required in the end, no matter what.
The way I see any room is to first listen, talk in it, walk around listening to voice, music etc at some different levels.. kinda see what possible absorbtion and/or (note the "and/or" part .. this is important!).
The math will illustrate the problems of standing waves in a square room, and how that changes as the dims change... a good idea to understand anyway.
For argument, I'd "round off" the room dims you have, start with that and see if it relates.
Remember, music and sound need room to move and breath, so a dead room is bad, a live room is bad (for mixing), and a good room is ones that doesn't promote any certain frequency .. and you don't feel like you're in a jet plane or a box. .. that's why I mentioned treatment as "and/or".

If your walls do not resonate that, IMO is the 1st step. Rooms are funny, you can build the same room exactly the same every time, but it won't sound exactly the same .. materials are not that consistant, nor are methods .. so you build, listen, and THEN adjust.

anonymous Tue, 01/14/2003 - 20:13

Hi.
Re the triangle setup for monitor speakers.
was talking to Mike Stavarau once [staff engineer at Monserat before it blew up], and he showed me how he positions monitors closer than usual and not realy in a triangle but facing more straight out. Gives larger sweet spot and better placement of centre sounds...like the allimportant vocal.
when monitors are widely spaced on large consoles the centre image seems empty and vocals lose their rightful presence.
Maak