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Monitoring position question Analog Processors (HW)
Old 13th September 2011
  #31
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Quote:
Originally Posted by Thiele View Post
Did you have an answer for the actual question I put forward?
Which bit of the answer I gave you in post #37 do you not understand?
Old 13th September 2011
  #32
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Quote:
Originally Posted by Starlight View Post
Which bit of the answer I gave you in post #37 do you not understand?
You spokesperson for Demor are you?
Old 13th September 2011
  #33
Quote:
Originally Posted by Thiele View Post
You spokesperson for Demor are you?
hehe, you're funny. You come on this forum and demand an answer. Rudely. If you don't like what people are saying here, then go somewhere where people want to be berated by an obnoxious little squat such as your fine self, clearly more interested in picking a fight than democratically finding an answer - they'd be happy to accommodate you.

Again... have some bloody respect for those who can be bothered to read the diatripe you submit on these forums and actually try and help.
Old 13th September 2011
  #34
jrp
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Answer: propably not. Because all rooms/walls are different there is no golden rule. never.

i did a lot of tests on this. Some ratios were bad, others worse. Some removed that huge dip at the center but brought new problems. I went back to center.
You can´t. Measure. Use your ears and listen. Use absorbers at all reflection points.

We have been very kind and gave you the information you wanted.
I was tought to treat even the rudest person with respect, so i gave you my thoughts on your problem. Now do this Forum a favor and leave. This is the worst User/thread i ever found on this otherwise great forum. No one likes to read your offenses.
Old 14th September 2011
  #35
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Quote:
Originally Posted by jrp View Post
Answer: propably not. Because all rooms/walls are different there is no golden rule. never.

i did a lot of tests on this. Some ratios were bad, others worse. Some removed that huge dip at the center but brought new problems. I went back to center.
You can´t. Measure. Use your ears and listen. Use absorbers at all reflection points.

We have been very kind and gave you the information you wanted.
I was tought to treat even the rudest person with respect, so i gave you my thoughts on your problem. Now do this Forum a favor and leave. This is the worst User/thread i ever found on this otherwise great forum. No one likes to read your offenses.
Thanks for the answer. I am beginning to warm to the place.
Old 14th September 2011
  #36
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Quote:
Originally Posted by Thiele View Post
Says the troll.

Did you have an answer for the actual question I put forward?
Yes


Quote:
Originally Posted by Starlight
Which bit of the answer I gave you in post #37 do you not understand?
Quote:
Originally Posted by Thiele View Post
You spokesperson for Demor are you?
I don't know if he is on my payroll........heh
Old 16th September 2011
  #37
Most designers and acousticians advocate not being in the center of a room front-to-back, but staying in the center left-to-right. A minority offset left-to-right to avoid the most significant interference from the axial modes between the two side walls, but the disadvantages in response from the left and right side of the stereo field outweigh the advantages in avoiding the node in the center. You are better off properly treating the side walls and staying centered.

In the case of the OP question, if you are constrained by circumstances and need to be off-center, there's no specific guideline like Wes' 38% suggestion for front-to back. Generally you want to stay a few feet away from any boundaries, so don't get too close to the side wall. Also, you don't want too great a difference from one side to the other. A small shift from center is all that is suggested by those who advocate this, the idea being to avoid the node but not make the stereo imaging problems too great. Again, I and most others avoid this offset, but since you have to do it, I'd say some experimentation is going to be helpful while being conservative about how far you offset. More than 10 or 15% offset and the imaging, especially re: bass, is going to be suspect.

A note about the 38% guideline - it was originally conceived for rooms with soffited monitors, so keep that in mind when considering it for free-standing monitors in home studios. It's a starting place for the DIY crowd, not a hard, fast rule by any means.
Old 16th September 2011
  #38
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Nice Jay! If that doesn't explain it it plain english, i don't know what will.

That's what i was trying to say with my earlier links aswell... (though not as stylishly of course =D):

https://www.gearslutz.com/board/6201284-post4.html


Quote:
Originally Posted by SörenHjalmarsson View Post

There is NO such rule mate! tutt

It is a theoreticall starting point assuming a perfect boundary condition. An optimized listening position in such a perfect room could be placed anywhere along the length of the room where the wavecycle is at it's origo point (i.e. in between the peaks and nulls) this, for example, will occur at 37.5%, 28.57%, and 42.85%.

However... as soon as real life elements come in to play (such as material impedance and openings etc.,) and sound wave phenomena such as diffraction, refraction and transmission occur, the theory is no longer valid. So to find the optimal starting point for any given (real) room, measurements are required - every room is a new room... there IS NO 38% RULE!! Why? Because most real life situations won't match the perfect theoretic model.


MVH
Sören
Old 16th September 2011
  #39
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Looking back on my posts i can see that i forgott to ad this one :

How important is the %38 rule?
Old 16th September 2011
  #40
Gear Guru
Symmetry

Just a couple of perspective points. Often the L and R walls are not built similarly. One may be brick the other stud. No bass symmetry possible.
I find the notion of bass symmetry a bit odd in any case. How do we get away with one sub?
HF symmetry and even MF symmetry is relatively easy to establish with say 4 inches of fibre with 4 inches of airgap behind.

I totally agree that testing and experimenting is the only way to a real answer here, but I would personally encourage trying off centre. Go for it and don't be afraid to try large offsets. Don't forget the same is true vertically. Sometimes a speaker can be placed upside down to optimise the woofer position.

I note that Boggy recently optimised the speaker positions in three rooms, using acoustic measurement. All three ended up around 19%, which is notably half of 38%

Overall, adherence to rules of thumb without perspective is the road to palookaville.
Like most of what we do in studios, there needs to be balance....

DD
Old 17th September 2011
  #41
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Good Points

Quote:
Originally Posted by DanDan View Post
Just a couple of perspective points. Often the L and R walls are not built similarly. One may be brick the other stud. No bass symmetry possible.
That's a good point, and one that is often overlooked. Symmetry of the speakers in relation to the listener, aswell as the room boundaries is paramount (check). But if you are to achieve a symmetric response, the actuall nature of the room boundaries needs to be taken into account aswell - the 'acoustic symmetry' of the room structure...

Solution?
This could perhaps be solved with 'unsymmetric trapping' (by building an inner shell that is symmetric from a HF point of view, while making the LF response so aswell), and/or by building a 'light' interior structure (symmetric or unsymmetric?) that evens out the impedance and response of the structure.

Quote:
I find the notion of bass symmetry a bit odd in any case. How do we get away with one sub?
I know that you and i are on different sides of the 'how subwoofers should be calibrated into the system' fence DD heh, but according to my notion, the subwoofer integration should also be made to be as symmetric as possible i.e. with one subwoofer for, and integrated with, each of the main speakers. Properly integrated this creates a more symmetric and realistic soundstage (than a single sub, calibrated to one of the mains) and the single difference from using subwoofes, as opposed to 'only' your main speakers, should be in the extended bandwidth they offer i.e. no symmetry issues - by using subwoofers, you build your own set of full range speakers (so to speak(er).

Single sub:
It is also possible to integrate a single sub succesfully! By placing the sub inbetween the main speakers (i.e. integrate the sub with both of the main speakers) one can also achieve a uniform LF response - although a separate LF transducer for each speaker is still preferable...

Quote:
I totally agree that testing and experimenting is the only way to a real answer here, but I would personally encourage trying off centre. Go for it and don't be afraid to try large offsets. Don't forget the same is true vertically. Sometimes a speaker can be placed upside down to optimise the woofer position.

Overall, adherence to rules of thumb without perspective is the road to palookaville.
Like most of what we do in studios, there needs to be balance....

DD
+1


MVH
Sören
Old 17th September 2011
  #42
jrp
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nice to see those posts being deleated and the return of this thread to a discussion on acoustics.
I would expect the problems becoming less obvios the more the room has been treated. Since directional hearing is less pronounced with lower frequencies and becomes impossible for the lower bass range it is still possible to be off center and have good stereo as long as all reflection points are treated.
Old 17th September 2011
  #43
Gear Guru
Subs

Soren, OT probably, but I doubt that we are on different sides! I experimented with 5.1 here, using a single sub. I much preferred 5 full range speakers. 3 of them do 30Hz, 2 are rated to 20Hz. Thus effectively as you suggest, subs integrated. I found, as others have, that multiple LF sources evened out the modes.

I didn't have the dual subs option but I am sure they would be quite good at mid wall.

+1 on unsymmetric trapping. Sometimes we may have to add mass and rigidity to a wall to get a balance. I believe this becomes more important as the room gets larger.

DD
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