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Discussion Starter · #1 · (Edited)
This Summer I bought a house and now I have my own music room. I've been reading a lot of stuff and I now have my room setup but it seems weird sitting so far back into the room. I'm running just a two channel setup right now as I want to get it perfect before I try again to add a sub.

My room is 13' wide and 15' 6" long (long side) or 12' 4" long (shortside)
My LP is 11' back from the front wall/window
Speaker are 6' 6" from the front wall/window
Speakers are 5' 8" apart
in about 3' 7" from the side walls
My LP's closest wall is just over 4 feet away

Treatment for this room will happen next year.

Do you guys think this is okay? I placed a UMIK-1 mic on the x-mas list for my wife but right now according to my phone SPL meter and ears I have a null at 80hz and 50hz about 15dB down but my sub should fix that.

All comments are welcome. :help:
 

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...now I have my own music room.
:TT:party::fireworks2::dancebanana::fireworks1:

I've been reading a lot of stuff and I now have my room setup but it seems weird sitting so far back into the room...

Do you guys think think is okay?
What kind of speakers? How are they angled relative to the LP? How do they sound to you now?

Is the ceiling flat? Angled (as can happen with upstairs or attic rooms)?

The speakers are positioned very close to the mid-way point from front to back of the room. At that mid-way point, there are more acoustical nulls, so it is to be avoided if possible for speaker placement. Same applies to the LP itself (although the mid point left-to-right is good for the LP - left/right symmetry, as much as possible, is a good thing).

Which is more important to you, imaging and soundstage? or frequency response? Of course you want both, but in real life one usually gets one right on with some sacrifices to the other, and the setup approach varies.

Just a few thoughts to get you started.

Others please speak up as well!!!
 

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Discussion Starter · #3 · (Edited)
What kind of speakers?
Mission 764i up front and a pair of Mission 761 directly off to the side and a little back at ear level for the rare time that I play a SACD or DVD-Audio in multi-channel (so only when I play Pink Floyd as I prefer my classical music in 2 channels SACD)
http://www.hometheatershack.com/forums/home-audio-speakers/20404-mission-76x-speaker-line-information.html

How are they angled relative to the LP? How do they sound to you now?
I do not know the angle but I followed the deep sound stage guide and it's toed in I would say less than 15 degrees. They sound plain at first but after a minute it feels like my rear speakers are on. The sound stage is very wide all around me but not deep. I can still tell how far away my speakers are and if the track has information in just one channel like a quick slap, the sound will come directly from the speaker position.

Is the ceiling flat? Angled (as can happen with upstairs or attic rooms)?
The celling is not flat. Picture from my home builders model home, close to mine.


The speakers are positioned very close to the mid-way point from front to back of the room. At that mid-way point, there are more acoustical nulls, so it is to be avoided if possible for speaker placement. Same applies to the LP itself (although the mid point left-to-right is good for the LP - left/right symmetry, as much as possible, is a good thing).
I read some were about positions that work best for not having nulls, .2, .32, .45, .55, .68, and .8 of the room. I believe my speakers are clos to the .45 point.
I've tried a few things and positions and I'm pulling my hair out with all the nulls that my room has. Just using my phones SPL meter the bass has huge swings in my room. This position is the "best" so far but I’m sure I can find better.

Which is more important to you, imaging and soundstage? or frequency response? Of course you want both, but in real life one usually gets one right on with some sacrifices to the other, and the setup approach varies.
My end goal is to feel as if I'm at the symphony. At least to be able to sit down and not have anything jump out at me or feel like something is missing. So frequency wise 16Hz to 17,000hz, dB wise I figured I was around 75dB on average but my phone tells me I'm around 90dB's on average.

My main Speakers are the weak point in my system and I hope to move to Arx A7rx-c in a few years or an OB system if my room is big enough. I'm not a big fan of subs as most sound too unnatural so I hope to be happy with my Paradigm Servo 15 version 1 until it dies or a couple of Rythmik F12g's if I can't tame the nulls.
 

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I do not know the angle but I followed the deep sound stage guide and it's toed in I would say less than 15 degrees. They sound plain at first but after a minute it feels like my rear speakers are on. The sound stage is very wide all around me but not deep. I can still tell how far away my speakers are and if the track has information in just one channel like a quick slap, the sound will come directly from the speaker position.
The placement of your mains and LP seem fairly typical of the setups we have gotten good results with. The two things I would focus on are:
  • Precise symmetry. Re-measure distances from speaker to front wall, to side wall, to LP.
  • Listening angle of speakers. A laser pointer or laser distance measurer used as a pointer is a must. Make sure the angles are symmetrical by aiming along the side (insides of both L & R or outsides of both L & R) to points on the LP chair that you have measured to be equidistant from the center of the chair. Be aware that very small changes in the angle can make a big difference in the character of the soundstage produced. With some speakers, a change in that angle of only one degree can have the effect of transforming a mediocre soundstage into a deep, dense, exciting one.

Some speakers will produce a better soundstage and image clarity than others. It seems reasonable that a room like yours with good front-of-room symmetry, with no obstructing furniture or objects on the front wall, should produce a pretty nice one. I have gotten room-filling soundstage and imaging with little 2-way bookshelves. I fully understand your impatience and frustration. Sometimes we get great results in three moves, sometimes it takes 30 moves.

The way the music is mixed can make a big difference, too. Well-recorded music does not necessarily mean it is conducive to a wide, deep soundstage. I will compile a list of tracks that are particularly striking with a good soundstage.

The celling is not flat.
Neither the slanted area of the ceiling nor the asymmetry at the back of your room should prevent being able to get a nice soundstage and imaging.

I read some were about positions that work best for not having nulls, .2, .32, .45, .55, .68, and .8 of the room. I believe my speakers are clos to the .45 point.
I've tried a few things and positions and I'm pulling my hair out with all the nulls that my room has. Just using my phones SPL meter the bass has huge swings in my room. This position is the "best" so far but I’m sure I can find better.
You have done your homework and are being thorough. Remember that every room has lots of nulls and that most nulls are narrow enough that they are inaudible. Go with the .45 point as you have, and work on symmetry and speaker angle (above). Until you can make swept measurements so you can see a plot of the whole frequency range at a glance, I suggest you stop chasing nulls. Picking at nulls with a SPL meter is a sure way to drive yourself crazy, because:
  • You will get different results a foot or a few inches away.
  • You simply will not hear them if they are narrow, and in your room, most of them probably are.

My end goal is to feel as if I'm at the symphony. At least to be able to sit down and not have anything jump out at me or feel like something is missing. So frequency wise 16Hz to 17,000hz, dB wise I figured I was around 75dB on average but my phone tells me I'm around 90dB's on average.
Audio phone apps can be really handy but are also notoriously inaccurate. The internal mic's frequency response is usually tailored for voice communications, with bass and highs drastically rolled off. It sounds like you are being driven by questionable data.

My main Speakers are the weak point in my system and I hope to move to Arx A7rx-c in a few years or an OB system if my room is big enough. I'm not a big fan of subs as most sound too unnatural so I hope to be happy with my Paradigm Servo 15 version 1 until it dies or a couple of Rythmik F12g's if I can't tame the nulls.
The A7 would be a dynamite choice. In the mean time, do not give up on your current set. "Endeavor to persevere" (movie??). You are on the right track. When you get there, it will have been worth all the trouble.
 

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I think Jon is calling it the L7, but it is based on the same model. I thing it's the same tweeter + a larger split gap woofer. He has them in prototype now, hoping they come out soon! He also is planning a matching center. I suspect they will be in my room when available. :T
 

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The sound stage is very wide all around me but not deep. I can still tell how far away my speakers are and if the track has information in just one channel like a quick slap, the sound will come directly from the speaker position.
Do you have an audio test disc to check phase? If not, some are available online.

I read some were about positions that work best for not having nulls, .2, .32, .45, .55, .68, and .8 of the room. I believe my speakers are clos to the .45 point.
I've tried a few things and positions and I'm pulling my hair out with all the nulls that my room has. Just using my phones SPL meter the bass has huge swings in my room. This position is the "best" so far but I’m sure I can find better.
Most of that "calculated" stuff is nonsense, especially in a real room, like yours, irregular shape, lossy walls, large windows, openings, etc.
May be best to wait until you get your UMIK measurement mic with sufficient resolution, before deciding on nulls - wide ones are bad, narrow/sharp ones will be largely benign audibly. It also depends on where the mic is placed.

cheers
 

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Discussion Starter · #7 ·
Well, I got my mic and my system is not as bad as I thought.

I also confirmed a few things: My highs are very weak and my Speaker do dig pretty deep I almost do not need a sub for my two channel setup.

I'm testing a few other speaker to see if it will be a better fix for my room.

I'm new to REW so can you guys look at my file and tell me about some of my problems??? :help:
 

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It is always best to measure L and R mains separately. It would be helpful to see the following plots:
  • sub
  • L main
  • R main
  • sub + L main
  • sub + R main
Your impulse diagram shows a lot of early reflections, which could be messing up your soundstage and imaging, but it is hard to tell for sure what course to take without seeing the L mains and R mains measured separately.

Your RT60 is not bad, but increases slightly into the high frequencies. Some room treatment might be in order to reduce the HF range. Again, separate L and R mains plots will make it easier to determine what action to take.
 

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Discussion Starter · #11 ·
Okay, here is the file.

I'm thinking the huge delay/overhang above 15,000hz is a glitch in the mic but maybe it is the new speakers. I will hook up the old speakers and see if this is happening.
 

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The measurements look valid. The high frequencies are probably correct. Before, when you measured with both speakers running at the same time, there was probably cancellation that made the highs look like they fell off above 3k with some comb filtering. The new measurements do not show that, as you would expect measuring only one speaker at a time.

What is the new speaker model?

Room asymmetry behind the LP is working against your soundstage and imaging (SSI) somewhat. You are closer to the rear of the room than to the front, so the asymmetrical reflections from behind you are playing a bigger role than the symmetrical reflection from in front - see significant reflection differences at 3 ms, 6 ms, and 13 ms (left) and at 11 ms and 13.5 ms (right). You might try shifting speakers and LP closer to front of the room and hopefully benefit from better symmetry of the early reflections there. Early reflections are not necessarily your enemy if they are symmetrical and arrive at the same time at the LP.
 

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Discussion Starter · #13 ·
Thanks
Old speakers are Mission 764i and the new speakers are JBL TLX 14, not much information on them on the net.

I was hoping some treatment might clean up some reflections.

Where can I read up on how to read the results??? Were do you see the 3ms 6ms and 13ms stuff???
 

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Thanks
Old speakers are Mission 764i and the new speakers are JBL TLX 14, not much information on them on the net.

I was hoping some treatment might clean up some reflections.

Where can I read up on how to read the results??? Were do you see the 3ms 6ms and 13ms stuff???
  • Click on the Show Overlays window button (hover to see the title)
  • Click on Impulse (top)
  • Make sure only the check boxes for plots #3 and #4 are checked
  • Set graph axis limits (upper right) > Left: -0.001, Right: 0.015, Apply settings, click Separate the traces (upper right)
Then you have to do some geometry and math. A laser distance meter comes in very handy about now.

For example, there is a big reflection at 13 ms (left) and another at 13.5 ms (right) that will mess with the imaging for sure. The main impulse at t=0 reaches the LP first. How far is speaker to LP? For our example, say it is 5 feet. Speed of sound is 1.1 ft/ms, for real quick estimations you can use 1 ft/ms and be pretty close, as we will now. The left reflection at 13 ms took 13 ms longer to get to the LP than the direct signal from the speaker. So the total path length is 5 ms + 13 ms = 18 ms from speaker to reflection point to LP, or 18 ft total path length (17.5 x 1.1 = 19.25 ft to be more accurate).

My guess is that the left reflection off the diagonal wall accounts for it, whereas the right reflection off the closed door will be delayed slightly longer. Use the laser distance meter and a mirror taped to the wall to get the angles right and measure the total distance of each path and do the math. Want to see if room treatment would get rid of a given reflection? Run the REW sweep with a 5 second delay and hold a loosely-folded blanket at the suspected reflection point and see if the particular reflection goes away. To hear the difference, you can have a buddy hold the blanket at that point while you listen, or rig up something temporary for a listening test (blankets, pillows, quilt batting, whatever the significant other will let you get away with).

Also, the previous suggestion was to shift LP and speakers forward in the room. If you do, be sure you go for left-right symmetry of speakers and LP relative to side walls.
 

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Why the decision to ditch the Missions and try the JBLs? seems a step back in my opinion.
 

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Discussion Starter · #16 ·
Why the decision to ditch the Missions and try the JBLs? seems a step back in my opinion.
I was thinking the same thing but I tested all my speakers and my Mission764i had the worse response in the high range. Even my smaller Mission 761 did better.
The Larger Mission 764i’s had a dip around 4k. The 8” driver seems to roll off too early before the tweeter can do its thing.

The kicker is that the JBL’s have a very centered sound for vocals. It seems that at any toe angle the vocals are dead center.
 

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Is the missions response curve after room EQ has been done? It could be simply just the EQ is not correct?
 

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Hmmm, something is off. Those missions should not exhibit that result. They should be much better up in the top end. My missions all use the same tweeter design.
 

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Discussion Starter · #20 ·
Hmmm, something is off. Those missions should not exhibit that result. They should be much better up in the top end. My missions all use the same tweeter design.
Tony, You got me thinking so I did a more detailed test a few days ago.

I did some close field tests with my three main Speakers. Mission 764i, Mission 761, and JBL TXL14

My Mission 764i is the only one with separate terminals.

Tweeter wise the JBL is the flattest and the one that goes the highest.

For the bass drivers the "sealed" Missions (my 764i looks like it has a port but it's loosely plugged on the inside) roll off slow and the 764i dig deep. the ported JBL drops fast but gains again in the really low end.

Next is the full range of all three at 1 meter. As you can see the JBL is the only one that stays flat at the high end.

As a side note I'm surprised that my Servo 15 is really low on power below 20Hz. it have a strong filter down low, I'm guessing to keep the distortion down.
 

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