Proper Speaker Placement

amplifiers, receivers and loudspeakers
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AsOriginallyRecorded
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Re: Proper Speaker Placement

Post by AsOriginallyRecorded » 06 Oct 2017 03:15

Not sure if you are still following this dialogue, but I think you can actually accomplish more than one objective with the cabinets. Obviously you will alter the shape of the room, at the same time gaining storage. But, using some sculpturing of surfaces of the cabinets ( a hard surface of any type will result in reflection of sound waves) using absorbing materials on exposed surfaces, irregular texture pattern treatments and set backs to the materials on or in the cabinets can serve to defeat those reflections significantly. A little artistic application and regard to the physics could produce a very notable difference in sound envelope. Quite interested in hearing how your changes affect the sound of your room! Bear in mind that every change to setting can positively or negatively affect the resulting output. Tread carefully, think creatively, and have fun! :D

tonylaibach
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Re: Proper Speaker Placement

Post by tonylaibach » 06 Oct 2017 09:36

Hi SpeakerMania,

Thx for that.
Incidentally, I AM looking into textured cabinet doors as diffusers.
http://www.ikea.com/us/en/catalog/products/70282893/

I can either do the entire cabinet (both side walls) with this door, or selectively at reflection points only.

My concern is whether the texture is pronounced enough as a worthy diffuser.

contented
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Re: Proper Speaker Placement

Post by contented » 07 Oct 2017 17:57

I have just tilted my speakers with packing on the front of the stands with the speakers on their spikes of course. It gives a better sound spread and realistic feeling especially while sitting higher or standing. It comes across better while cooking in the adjoining kitchen and when upstairs on the computer with the volume adjusted accordingly. Good thing that my neighbours are a long way off. Does this sound daft or not, imaginative wise?
contented.

Guesstimator
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Re: Proper Speaker Placement

Post by Guesstimator » 25 Feb 2018 18:39

Hi all

i have been playing with speaker placement in myattic space.
room is 4.96m (16ft 3.3") long and 4.40m (14ft 5.23") wide. Speakers are firing down the room (4.96m).
After an afternoon experimenting with wall proximity for bass response and speaker/seating ratios for image i have settled with the speakers a fair bit from the walls and the sitting position quite close to the speakers. This gives the deepest soundstage and instrument positioning is really focused. Drum spacial presentation is spot on (a drum roll lets you tell where all the drums and cymbals are) and voice is perfectly centred and comes from beyond the speakers (if it makes sense) giving a real sense of depth. Speakers are 1.5m from the front wall and 1.1m from side walls, toe'd in to meet just behind my head. my head in the seating position is 1.75m from the rear wall and it turns out that like this my head and the speakers form and equilateral triangle (well, nearly, 2.20m base and 2.1m sides) this was not sought out it's just where i ended up. I really like the presentation, its like being in a room with the musicians BUT, i have noticed not all is well with bass. It seems there are some frequencies missing, like the really low tones, when you expect the bass guitar punch , sometimes it is there and sometimes not depending on frequencies. For example Low E string notes on the fist 7 frets kind of "recede" while second string ("A") from say "C" upwards are there clear and strong . However if I move closer against the rear wall (say backing up by 1.2m untill i am 0.5m from the rear wall) I get great bass detail and extension, at the expense of sound stage depth and focus.
This is really frustrating as i LOVE the soundtsage depth i am getting. I have tried moving the speakers around some more but every time i move them away from me towards the front wall I lose soundstage focus and no real gain in bass clarity.

I am aware that it is a very specific issue, and to be fair my system is sounding better than ever before, but if anybody has any suggestions it would be greatly appreciated.

Cheers
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Old Geezer
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Re: Proper Speaker Placement

Post by Old Geezer » 25 Feb 2018 23:49

Guesstimator, you are chasing the impossible but achieving what is as good as it gets. In my selling stereo equipment days, the late 60's to late 80's I went to many Magnavox, RCA, Sony Panasonic, etc. schools about sound reproduction. Even with the most expensive seats in the house, you never get "perfect" sound. Simply moving one's head causes changes. Treble sounds travel in straight lines while bass floats...at least that is what all the specialists say. Tilting tweeters up to bounce off the ceiling/far wall to fill the room top to bottom and placing bass woofers to send sound around the room to fill it wall to wall, one gets all the notes available from the source radio, CD, tape, etc. to the max. Find music you love and enjoy!

Guesstimator
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Re: Proper Speaker Placement

Post by Guesstimator » 04 Mar 2018 18:19

Hi all,

Not the one to give up, I decid d to build two bass traps (1.35m X 0.6m 16 cm rockwool+ 5cm thick frame) that straddle the corners of the front wall (behind the speakers). And I know have bass!! The bass is no longer disappearing on particular notes and my system has never sounded better. I am now waiting for some thick curtains to cover a window that is where the first reflection point of the lh speaker is. And will build a some more panels.....one for the first Rh reflection point two that will extend the current bass traps to the ceiling and one to place on the rear wall.

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Re: Proper Speaker Placement

Post by Sunwire » 04 Mar 2018 22:15

I think blocking/absorbing first reflections makes a very large difference, especially in helping to reproduce an accurate stereo image.
You want the direct sound from the tweeter to be MUCH, MUCH louder than any early reflections from the side walls, floor, ceiling.
If you, like many of us, have a table in front of your seating position, either remove it or cover it with soft absorbent material for critical listening. I have a table in front of my listening couch. For critical listening I put several large soft pillow on it. It makes a difference!
Thick carpet or pillows at the first reflection point between you and the speaker really helps too.
Use small mirrors you can move around the room to help find these reflection points. If you see the tweeter in the mirror from your listening position, that's the reflection point.
Your distance from the rear wall can make a big difference, too. Both for treble and for bass.
I have to sit a couple of feet away from the wall behind my couch for the bass balance to be right. If I lean back, the bass gets very wooly and too loud.

Nebulus
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Re: Proper Speaker Placement

Post by Nebulus » 06 Mar 2018 16:32

Sunwire wrote:I think blocking/absorbing first reflections makes a very large difference, especially in helping to reproduce an accurate stereo image.
You want the direct sound from the tweeter to be MUCH, MUCH louder than any early reflections from the side walls, floor, ceiling.
If you, like many of us, have a table in front of your seating position, either remove it or cover it with soft absorbent material for critical listening. I have a table in front of my listening couch. For critical listening I put several large soft pillow on it. It makes a difference!
Thick carpet or pillows at the first reflection point between you and the speaker really helps too.
Use small mirrors you can move around the room to help find these reflection points. If you see the tweeter in the mirror from your listening position, that's the reflection point.
Your distance from the rear wall can make a big difference, too. Both for treble and for bass.
I have to sit a couple of feet away from the wall behind my couch for the bass balance to be right. If I lean back, the bass gets very wooly and too loud.
Totally agree! Improve sound quality drastically by putting four EQ Acoustic (UK) pannels placed on the first reflections points. I'll put another four of then when budget increase.
39964

Old Geezer
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Re: Proper Speaker Placement

Post by Old Geezer » 07 Mar 2018 17:22

I think all of us audiophiles are chasing the impossible dream...but we keep trying. Rather than crossover-networks inside one speaker cabinet housing several speakers, multiple speakers in separate boxes covering the complete sound range (roughly 20 to 20K) would probably be more realistic. An orchestra/band is not confined to a little...or even BIG box, but is spread out across a stage/sound studio. Imagine 10 speakers with 5 right and 5 left of the amp. with 1000 cycle (sorry, I'm old) hertz horns pointing forward, tweeters covering below 1000 down to 600 facing slightly outward, then mid-range covering voice frequency facing up and out with bass point right and left. The frequencies can vary according to one's taste but that should reproduce a realistic studio/orchestra sound. I have thought about doing this but being a custom car builder (1965 Mustang), licensed gunsmith (police dept.), working on electronics as a hobby and building my retirement house, this is basically a dream idea.

Guesstimator
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Re: Proper Speaker Placement

Post by Guesstimator » 13 Mar 2018 23:38

Hi All

just download the REW software and measured the frequency response from my listening position. There is a massive dip between 32 and 71 Hz and then again between 100 and 145...and another between 240 and 300...i have already built some bass traps that straddle the front wall corners (6" thick rockwool 70kg/m^3 with 2" frame spacing). i have moved the speaker closer to the front wall (by 23") reducing the dip but soundstage disappears....any suggestions??

cheers

Mat
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Sunwire
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Re: Proper Speaker Placement

Post by Sunwire » 13 Mar 2018 23:50

Set speakers where you previously got good imaging, then retest after moving your listening position forward and back by six inch increments at a time. See how bass response changes with each move.
Make sure woofers are not same distance from side walls as they are from front wall.

Sunwire
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Re: Proper Speaker Placement

Post by Sunwire » 14 Mar 2018 00:42

I'm sure part of your problem is due to standing waves in the room.
I think you need to find both listening location and speaker location that is neither at a peak nor at a trough of the major standing waves in your room. There should be three major standing wave frequencies, each one determined by one of the three major room dimensions: length, width, and height.

Some good info and further links here:
http://www.acousticfrontiers.com/room-modes-101/

Guesstimator
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Re: Proper Speaker Placement

Post by Guesstimator » 17 Mar 2018 11:26

Thanks for the info, i had a look at the linked site and started doing a series of measurements with varying front wall distance as well as seat position.

I have the two significant scenarios i ended up with are:

Speakers very close to wall: to get the speakers in this position i also need to move them apart as they fit beside the turntable and telly furniture. In this case i get decent bass reinforcement between 50 and 70 hz but develop a significant trough at 100hz and the response is more affected by sudden spikes at various frequencies. Also in this position soundstage depth has completely disappeared as has any kind of sense of instrument position.

Speakers further out from the front wall and very little toe in: excellent soundstage depth and bass guitar detail (listening to Geddy lee's early rush tracks fron 2112), good drum space left to right (although a drum roll is not as spacious nor as focused as could be left to right)voice bang on in the middle. bass reinforcement is not as pronounced as in the near wall position but it is much fuller to the ear over a wider range of frequencies. I performed the final frequency sweep after small toe and fore/aft adjustment made while listening to records. Bass frequencies are indeed much better although i cannot get rid of the dip between 30Hz and 50 Hz.also i have developed a more significant dip at about 130 Hz although throughout the rest of the range the response is a bit smoother
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all curves are smoothed at 1/24th

I have also checked the decay spectrograms and times are greatly reduced , and by the phase plots i can see that i have removed a phase cancellation at 53Hz.
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i tried bringing the speakers further forward but response worsened.

Now, my speakers are Monitor audio Bx6 with front and rear ports. i am wondering if the dip between 30 and 40 hz is related to the speaker design? could a sealed speakers say ar3a or ar6 respond differently in my room (i am quoting AR just because i recently heard a pair at my father in law's and thought they had prodigious bass although sounstage was non existent due to the classic positioning in a bookshelf and way too far apart).

i tried measuring the effect of using bungs in the ports but all i get is a reduction in bass response up to 500hz.

at the moment i have no bass traps on the side walls at the 1st reflection points so will soon rectify that, however i am still concerned in the dip in the lower range that has not been affected by any speaker positioning or even bass traps positioning ( tried removing the bass traps in the front corners and placing them at 1st reflection points but the issues caused by removing them in the corners far outweighs any benefit i can measure from reducing side reflections).
Anyway, any though or suggestions are more than welcome.

Cheers all

lreneat
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Re: Proper Speaker Placement

Post by lreneat » 18 Mar 2018 00:16

As is a kitchen configuration of sink, fridge and stove being at the far ends of a triangle from one another, so is the position of listener to speakers. Mids and tweets should be at head level where listener plants their rear. Now, was that so hard?

Sunwire
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Re: Proper Speaker Placement

Post by Sunwire » 18 Mar 2018 03:00

Can you change your listening position, closer or farther from the speakers?
Are you measuring frequency response right at your head position?

Absorbent material at the first reflection points is for the purpose of absorbing mid and high frequencies. It probably won't have much effect on bass response.
Bass response is affected most by the room dimensions and the distance of the speakers and the listeners from room boundaries.
So, bass is best dealt with by speaker placement and by listener position. Just as an experiment, put on a track with good deep bass, then start listening right up against the back wall. Slowly move forward toward the speakers and notice how the bass changes as you do. Or use filtered pink noise as recommended in this article, which is mostly about using bass traps:
http://arqen.com/bass-traps-101/placement-guide/

I just tried this and noticed how the deep bass gets stronger and weaker as I move through the room. You can directly experience the standing waves in your room.

I have never been able to get good stereo imaging unless the speakers are out in the room, away from the wall. So, that's kind of a given, except with certain speakers specifically designed for wall or corner placement.

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