Axiom Home Page Forums General Discussion Stereo Speaker Placement

It's been a long time since I've posted here, with a few recent exceptions. I think I'll resume posting here as it will be much like talking to myself. Perhaps the faithful have chased everyone away.

Anyway, I followed the Home Theater Shack $3,000 speaker comparison with interest. I had previously ordered an Odyssey Khartago which should ship tomorrow. As a result of the HTS discussion, I ordered a pair of cherry M100 V4s. I offered a price so low, I hoped it would be rejected, but Debbie said yes, so they should be here by Wednesday.

More to the point, the reviewers commented on the sonic virtues of moving the speakers away from the wall. I have a pair of Thiel CS 3.6s which sounded OK, I have to say I've been disappointed in them for years. So, tonight, I moved them away from the wall. Wouldn't you know it, but those fellas were right. What a huge difference in sound quality.

Also made me appreciate the Integra M504 amplifier which drives the Thiels. Nice amp. Had a bit of a chuckle at the assertion that all solid state amplifiers sound the same.

Anyway, I am looking forward to setting up the M100s. I'll keep them away from the wall as well.

Until next time.

Phil, I'm setting up a new room up stairs strictly for straight up stereo.

The room is 11 feet wide and 20 feet long. I have my Dreamcatchers on make-shift stands a quarter of the way into the room. I am sitting a quarter of the way into the room so about 5 feet from the back wall and 10 feet away from the speakers. The speakers are about 10 feet apart. I've placed some room treatments Hell_Commute gave me before he turned into Serenity_Now.

It's not perfect yet but the sound stage is absolutely amazing. It's deep, tall and wide. I can't say it's ideal with all recordings but there have been a few CDs where you'd never know you were in a residence.

I can't have a musical experience like that in my basement with the large Axiom system although there are other benefits with that system related to movie watching. The big problem I have in the basement is that I am sitting too darned close to the M80s (8 feet) and they are a foot away from the wall. It's a damned shame!

I'd love to try a bigger, three way "bookshelf style" speaker in this setup.

I hope you're still enjoying your tube gear.

I have wondered about the magic numbers that some of these magazines have published.

At the Home Theater Shack test they said their speakers were 56" away from the side walls, and 123" apart, so the width of the room was 19.5' wide.

They also said you so you should have the speakers a good 84" (7') from the wall. The M100 are 17" deep, so the front of the speakers are about 8.5' from the wall.

According to an expert placement guru Jim Smith, the listener should 1.2x away from the speaker as the distance the speakers are apart. So that would make your head 12.3' away from the speakers, or 20.8' away from the wall. There also needs to be at least 5' behind your head to the back wall. So the room needs to be around 26'x19.5'.

That is one heck of a big room. For the most of us who don't have room's that size to dedicate to listening, then we must compromise. If you move the speakers to being only 6' apart, then your chair can be 7'4" back from the speakers reducing the room size needed down to 20'x15.5'.

Now I wonder, if you are trying to do home theater, does the 5' from the back wall still apply, or do you need more?

Now I have almost finished my listening room. It feels pretty big, but nowhere near the numbers above. The room is 15.5' wide by 17' deep at the largest dimensions. There is a 1' jog in at the front left of the room for the electrical panel, and a 1.2' jog in at the back right of the room where the furnace room wall is.

Based on the distances of 5' behind my chair (i'll even give myself 4' for the furnace room bit) and the 8.5' from the front wall, that leaves in my room 3.5' from my head to the front of my speakers. I guess that I will have to live with far less than the recommended 7' offset from the rear wall.

Hello Matt. I need a bigger living room! I can pull them out about 5' from the wall for sitting down and getting into it. Enough room for about 8' between the speakers. That' leave me about 10' to the couch, but the couch is up against the wall. Currently, I have a pair of Dahlquist DQM909s atop a pair of Dahlquist subwoofers driven by a legendary Yamaha M80 amplifier (B&K reference preamp) I'll swap the Dahlquist arrays for the M100s.

My 9.2 system is in the master bedroom, which is pretty big. I placed the Thiels about 3.5' from the wall. I'd say (I'll measure later) that the distance between the speakers is about 9'. My listening position is a bit too close (~6') because of the bed.

Moving the Thiels away from the wall has definitely helped in a big way. Never occurred to me before. What a difference.

Mojo, it sounds like you have pretty much taken the wall behind your speakers out of the reflection equation (especially if treated). Love to hear those dreamcatchers!!

I didn't want to get too excited about the M100s, but my toe is tapping with expectation.

My tube amp needs a bit of professional attention. I keep it dusted.

Here you go for a typical room. Based on the Math of Grimani\Everest\Winer. Audio is Physics. Physics is math. Speaker Placement is easy. Take the room out of the equation the best you can using these ratios and treatment techniques.

Proper setup is the best thing you can do for your system, and it is FREE!!

Symmetry is important for timing and proper imaging. Use a tape measure and take your time. I even put a graduated scale behind the MLP and shoot a laser on top of the speakers towards my MLP to match toe in exactly. Makes a huge difference. The speakers should be level, firmly affixed to the floor with spikes, or to their stands with blutac or similar.

If you can, try to have the furnishings in the room evenly placed. One side of the room should not be acoustically dead (drapes and a sofa) while the other is hard reflections like bare drywall and pictures.

Here is how it is done:

There are known room length ratios which modes are at their best behaved. These are 0.2/0.32/0.45/0.55/0.68/0.8 times the room length\width. (Grimani\Winer) Placing yourself and the speakers in these positions relative to the rooms dimensions will avoid exciting\receiving Axial modes and coloring the sound where possible.

Using these ratios will yield a flatter response and a natural presentation. Notice how 0.2 and 0.32 correspond to the thirds and fifths rule everyone quotes all the time.

I agree with Matt that most speaker setup Gurus state the speakers should be placed 0.85x the distance to the listener apart. (Acoustic Frontiers) Luckily, this is easy to achieve in Mojo's room with the ratios above. Almost ideal actually. Placing speakers closer together than the equilateral triangle rule is a good idea. It lends more focus and gets the speakers further from the sidewalls. Toeing in the speakers also reduces treble sidewall reflections. It also increases direct treble energy and can give a "the singer is right there" live and focused phantom image. Experimenting with toe-in is a great idea.


Example 11x17 room (common dimensions)

Speaker From sidewalls width x 0.2
Speaker From Front wall length x 0.2
Listening position length x 0.68



Mojo, here is yours. I took more care in measuring the dimensions so they are pretty close.

Speaker From sidewalls width x 0.2
Speaker From Front wall Length x 0.32
Listening position length x 0.68




The first reflection panels should cover the hot spot at 9 to 10 feet from the front wall. 1'corner traps should straddle front tri-corners (set them on floor in front corner or hang in top corner.)

Wow

You havent met DrStrangequark yet...... I dont deserve any wow!

I disagree. I think hard about this stuff but certainly not as clearly or with such good documentation as you. I think your post deserves some wow.

*bridgman goes searching for some of DrStrangequark's posts, hoping he doesn't have to come back here and eat his words

Trevor, thanks for the acoustical engineering. That configuration was the first thing I tried . Yes, it is good and for the vast majority of CDs the speakers disappear. The center image is also perfect. But what was lacking was a wide and deep sound stage with the ability to discern the instruments across it.

So that's when I moved them closer to the front wall (3 feet away) and spaced them as far apart as I could. This does indeed make the sound stage very, very wide and deep and gives greater spatial resolution to the instruments. The center image is also fantastic. However, on some CDs, I can't say the speakers disappear the way they do with "your" configuration.

The trouble with the Dreamcatchers is that they really need "a lot" of power for the midrange to bloom. And just as they start to bloom, the bass bottoms out. This is the problem I have with the second configuration. Without a sub, I can't turn the damned things up to get great midrange.

So the bottom line is I need the Axiom Air Gateway to have a sub out :-).

There's a world of difference in my room with your treatments by the way. I knew they would eventually find a good space in my place :-).

Cool, you tried it!

A fellow tinkerer! I enjoy the dissapearing act too.

Glad to hear it worked well. Not much to say about the panels except to fully agree with you. In my old room it was night and day too. They are so cheap to make. Great bang for buck sound upgrade.