OK...I think we're onto something with the tilt here...Check it out. I like the feel and look too. Gonna keep it either way.
file sent...
Also I edited the post above with a pic of the sub...
CR Treatment and Tuning---The home stretch!!
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Stadank0
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Soundman2020
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Re: CR Treatment and Tuning---The home stretch!!
There is an improvement, yes, but the reflection is still there. Slightly lower intensity, and slightly earlier in time (very slightly!).
Here's what it looks like:
Gold-colored curve is without the desk tilt, purple curve is with the desk tilt. You can see that the level came down a little and the spike moved earlier by a few microseconds (about 70 us). It came down from about 46% to 39% in energy, which is nice, but not enough. It's a useful change, yes, but the issue didn't go away completely... It would have to get below the 10% line for me to consider it fully resolved.
The fact that it moved earlier in time means that it took a slightly shorter path, which suggests that the reflection point moved higher up in distance above the floor.... so it is probably now located more towards the back of the desk (I assume you lifted the rear of the desk?) It also smoothed out from being two spikes to now being just one, so I'll go out on a limb and say that previously the reflection point was straddling the desk surface and the rebated "console tray" section, but now it is all on the top surface, none on the tray. That puts it quite far back on the desk, in that triangular shaped area next to the tilted rack section, and in a direct line from the speaker to the mic. Try putting a patch of insulation back there on the "triangle", and see what happens. Dinner-plate sized piece of insulation...
But if you like your desk like that, then you can keep your desk like that!
However, we do still need to find the source of that reflection, and knock it down a bit more. Under ten % is the goal!
So it's time to get out your string and masking tape!
- Stuart -
Here's what it looks like:
Gold-colored curve is without the desk tilt, purple curve is with the desk tilt. You can see that the level came down a little and the spike moved earlier by a few microseconds (about 70 us). It came down from about 46% to 39% in energy, which is nice, but not enough. It's a useful change, yes, but the issue didn't go away completely... It would have to get below the 10% line for me to consider it fully resolved.
The fact that it moved earlier in time means that it took a slightly shorter path, which suggests that the reflection point moved higher up in distance above the floor.... so it is probably now located more towards the back of the desk (I assume you lifted the rear of the desk?) It also smoothed out from being two spikes to now being just one, so I'll go out on a limb and say that previously the reflection point was straddling the desk surface and the rebated "console tray" section, but now it is all on the top surface, none on the tray. That puts it quite far back on the desk, in that triangular shaped area next to the tilted rack section, and in a direct line from the speaker to the mic. Try putting a patch of insulation back there on the "triangle", and see what happens. Dinner-plate sized piece of insulation...
But if you like your desk like that, then you can keep your desk like that!
However, we do still need to find the source of that reflection, and knock it down a bit more. Under ten % is the goal!
So it's time to get out your string and masking tape!
- Stuart -
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Stadank0
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Re: CR Treatment and Tuning---The home stretch!!
oh alright then..... 
Quick question though...Hows about I put some insulation in the picture frame to keep it from resonating?
Quick question though...Hows about I put some insulation in the picture frame to keep it from resonating?
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Soundman2020
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Re: CR Treatment and Tuning---The home stretch!!
I was actually going to suggest that if I saw it misbehaving in the REW data.... But sure, no problem! Go ahead and do it preemptively: it will save you extra work taking it down and putting it back up, if it does turn out to be necessary...Hows about I put some insulation in the picture frame to keep it from resonating?
- Stuart -
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Stadank0
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Re: CR Treatment and Tuning---The home stretch!!
I'm having a hard time understanding your string directions. I don't understand the how marking a spot with a sharpie comes into play. I also don't understand the concept of moving the slack around the room.
I'm sure this is difficult to convey in messages so I'm sorry that I'm not picking up what you're throwing down. LOL
I do understand the idea of taping the string to the acoustic Center and taping the string to the mic and the slack hanging down. I'm not sure how I'm supposed to move that slack around the room effectively if it's attached to two fixed points. How does the Sharpie come into play if I'm attaching the string to two fixed points? Maybe I'm not?
I'm sure this is difficult to convey in messages so I'm sorry that I'm not picking up what you're throwing down. LOL
I do understand the idea of taping the string to the acoustic Center and taping the string to the mic and the slack hanging down. I'm not sure how I'm supposed to move that slack around the room effectively if it's attached to two fixed points. How does the Sharpie come into play if I'm attaching the string to two fixed points? Maybe I'm not?
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Soundman2020
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Re: CR Treatment and Tuning---The home stretch!!
The sharpie just marks the exact length on the string. The distance that you are trying to trace. If you don't like sharpies, then you can also use a pen, pencil, nail polish, paint, or a quill dipped in ink... 
Anything that leaves a clear mark on the string at the two points you need.
So, first lay out a long piece of string on the floor, then a couple of inches from one end, mark the string with the sharpie (or quill). That "couple of inches" is to give you enough extra string so you can tape it securely to the speaker. The the sharpie/quill mark is the spot that just touches the front panel of the speaker.
But with the string still on the floor (before you pick it up to tape it to the speaker), measure from that first sharpie mark the distance that I specified above: that is, the distance from the tip of the mic to the acoustic center of the speaker (the "axis" in the model: just below the tweeter), PLUS the extra "bounce distance", which is 33 cm EXTRA in this case. Make another mark on the string at that exact spot (mic-speaker distance + 33 cm) , and that second sharpie mark is the spot that has to end up at the very tip of your mic. A couple of inches beyond that second sharpie mark, you can cut the string. You now have a piece of string that is a few inches longer than the total bounce distance, with tow marks on it, and a but extra beyond each mark, for taping.
So, your string has two sharpie marks on it: one of those you position exactly at the tip of the mic and tape in place, and the other you position exactly at the acoustic center of the speaker and tape in place. The sharpie marks are just there so you can be accurate with the taping up of the string. 1ms is a very short delay, so you do need to be very accurate here, thus the sharpie marks: to give you accurate points for taping up the string.
OK; so now you have your string taped up, with one mark where the string meets the speaker, and the other mark where the string mics the mic, and the middle of the string is hanging down, but in a natural curved shape: Sound does not travel along curved lines: it travels in STRAIGHT lines, (at least for high frequencies in air....). So you need to use your finger to push down in the middle of that loop of slack, so that the string is stretched taught on either side of your finger into two straight segments. On one side of your finger the string now runs in a straight line to the speaker, and on the other side in a straight line to the mic.
As you run your finger along the string like that, at some point it will touch the desk surface: the point where it touches is the center of the specular reflection that is causing the problem. You might find that you can move the string left and right a bit, with your finger still pressing to keep it taught, and it still touches the desk surface. For example, you might find that there is one spot you can reach on the desk surface, and another on the "console tray" surface, and another on the vertical side of the angled rack section. All of the spots that you can reach with your finger like that, keeping the string taught in both directions, are likely part of the reflection. Put small pieces of masking tape at every spot you can reach with your finger pressing on the string.
You might need help here: as you press down, the mic stand will want to topple over, or the tape might come loose at the speaker. So if you can find some helpful volunteers to hold those to spots steady, that would help!
In this first case, there's only enough extra loop that it can touch the desk surface: the loop isn't long enough to reach other surfaces. But for the OTHER ones that I mentioned, the bounce is quite a bit longer (several ms), so the string will be quite a bit longer too (roughly one foot longer for every ms), and could potentially reach many surfaces. For example, if the loop hangs down to the floor, you might find that you can also stretch it out sideways and touch the wall in a few spots, as well as stretching it upwards to touch the cloud in a few spots. If that happens, then mark ALL of those points with a bit of masking tape.
If you take a look at Steve's thread, in the most recent photos you can see some colored markers on the front walls, floor, and soffit wings where he did this exact same process, and found several potential reflection points, which I am about to deal with. The different colored markers are for different string lengths = different flight times. That's the end result of this process: a bunch of markers on the desk and around the room that show where your strongest reflections are coming from.
Finally, not all of the points that you can reach with your finger really are reflection points: To be CERTAIN that it really is a reflection point, the "angle of incidence will be equal to the angle of reflection". So look closely at how the stretched-taught string touches the surface: the angle that it makes on one side of your finger (heading towards the speaker) between the string and the surface should be about the same as the angle of the string on the other side (heading towards the mic). If the angles are clearly very different, then that's probably not a refection point, but if they are similar, it probably is. In other words if the sound wave (string) is hitting the surface at an angle of 60°, but the angle from there to the mic is only 20°, then that's not a reflection point beause sound always bounces off a flat surface at the "same but opposite" angle: if it came in at 60°, then it will leave at 60° the other way. But if the second angle in this example (string to mic), is also about 60°, then it is a reflection point. The angles might be anything: both 20°, both 8°, both 41.297°, both 81.6°, or whatever), but they will be equal for all spots that really are causing that reflection to hit the mic (your head)
Not sure if that cleared it up a bit! Or maybe just confused you even more...
- Stuart -
Anything that leaves a clear mark on the string at the two points you need.So, first lay out a long piece of string on the floor, then a couple of inches from one end, mark the string with the sharpie (or quill). That "couple of inches" is to give you enough extra string so you can tape it securely to the speaker. The the sharpie/quill mark is the spot that just touches the front panel of the speaker.
But with the string still on the floor (before you pick it up to tape it to the speaker), measure from that first sharpie mark the distance that I specified above: that is, the distance from the tip of the mic to the acoustic center of the speaker (the "axis" in the model: just below the tweeter), PLUS the extra "bounce distance", which is 33 cm EXTRA in this case. Make another mark on the string at that exact spot (mic-speaker distance + 33 cm) , and that second sharpie mark is the spot that has to end up at the very tip of your mic. A couple of inches beyond that second sharpie mark, you can cut the string. You now have a piece of string that is a few inches longer than the total bounce distance, with tow marks on it, and a but extra beyond each mark, for taping.
So, your string has two sharpie marks on it: one of those you position exactly at the tip of the mic and tape in place, and the other you position exactly at the acoustic center of the speaker and tape in place. The sharpie marks are just there so you can be accurate with the taping up of the string. 1ms is a very short delay, so you do need to be very accurate here, thus the sharpie marks: to give you accurate points for taping up the string.
OK; so now you have your string taped up, with one mark where the string meets the speaker, and the other mark where the string mics the mic, and the middle of the string is hanging down, but in a natural curved shape: Sound does not travel along curved lines: it travels in STRAIGHT lines, (at least for high frequencies in air....). So you need to use your finger to push down in the middle of that loop of slack, so that the string is stretched taught on either side of your finger into two straight segments. On one side of your finger the string now runs in a straight line to the speaker, and on the other side in a straight line to the mic.
As you run your finger along the string like that, at some point it will touch the desk surface: the point where it touches is the center of the specular reflection that is causing the problem. You might find that you can move the string left and right a bit, with your finger still pressing to keep it taught, and it still touches the desk surface. For example, you might find that there is one spot you can reach on the desk surface, and another on the "console tray" surface, and another on the vertical side of the angled rack section. All of the spots that you can reach with your finger like that, keeping the string taught in both directions, are likely part of the reflection. Put small pieces of masking tape at every spot you can reach with your finger pressing on the string.
You might need help here: as you press down, the mic stand will want to topple over, or the tape might come loose at the speaker. So if you can find some helpful volunteers to hold those to spots steady, that would help!
In this first case, there's only enough extra loop that it can touch the desk surface: the loop isn't long enough to reach other surfaces. But for the OTHER ones that I mentioned, the bounce is quite a bit longer (several ms), so the string will be quite a bit longer too (roughly one foot longer for every ms), and could potentially reach many surfaces. For example, if the loop hangs down to the floor, you might find that you can also stretch it out sideways and touch the wall in a few spots, as well as stretching it upwards to touch the cloud in a few spots. If that happens, then mark ALL of those points with a bit of masking tape.
If you take a look at Steve's thread, in the most recent photos you can see some colored markers on the front walls, floor, and soffit wings where he did this exact same process, and found several potential reflection points, which I am about to deal with. The different colored markers are for different string lengths = different flight times. That's the end result of this process: a bunch of markers on the desk and around the room that show where your strongest reflections are coming from.
Finally, not all of the points that you can reach with your finger really are reflection points: To be CERTAIN that it really is a reflection point, the "angle of incidence will be equal to the angle of reflection". So look closely at how the stretched-taught string touches the surface: the angle that it makes on one side of your finger (heading towards the speaker) between the string and the surface should be about the same as the angle of the string on the other side (heading towards the mic). If the angles are clearly very different, then that's probably not a refection point, but if they are similar, it probably is. In other words if the sound wave (string) is hitting the surface at an angle of 60°, but the angle from there to the mic is only 20°, then that's not a reflection point beause sound always bounces off a flat surface at the "same but opposite" angle: if it came in at 60°, then it will leave at 60° the other way. But if the second angle in this example (string to mic), is also about 60°, then it is a reflection point. The angles might be anything: both 20°, both 8°, both 41.297°, both 81.6°, or whatever), but they will be equal for all spots that really are causing that reflection to hit the mic (your head)
Not sure if that cleared it up a bit! Or maybe just confused you even more...
- Stuart -
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Stadank0
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Re: CR Treatment and Tuning---The home stretch!!
I'm going to digest that in a sec.....In the meantime I did found the 1ms issue.. I'll post a pic in just a minute. I'm fine tuning the spot with insulation now. I used a little rug and a towel to get the rough idea after moving them around the desk.
back shortly...
back shortly...
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Soundman2020
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Re: CR Treatment and Tuning---The home stretch!!
Read it over again: I just edited a bit, to make it clearer... maybe!- Stuart -
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Stadank0
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Re: CR Treatment and Tuning---The home stretch!!
OK...I sent you another file..AS you can see in the pic, The right side needs a bit more coverage. Also, the monitor controller is affecting that side. I could mount a keyboard shelf underneath the center to put it there along with the keyboard of course...Man! This is quite finicky!!! 
I did note that the LRS did not show a big change but the L/R measurement did? The cummulative affect seems to still be substantial despite a big improvement in the L/R measurements.
I did note that the LRS did not show a big change but the L/R measurement did? The cummulative affect seems to still be substantial despite a big improvement in the L/R measurements.
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Stadank0
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Re: CR Treatment and Tuning---The home stretch!!
Some art for the CR! 
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Soundman2020
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Re: CR Treatment and Tuning---The home stretch!!
Very cool Frank. I really like the color scheme you chose for the room, and I LOVE the LED lights. And the painting fits in very neatly too!
But please send me some REW tests! I'm itching to see how that latest set of digital tuning settings is turning out...
- Stuart -
But please send me some REW tests! I'm itching to see how that latest set of digital tuning settings is turning out...
- Stuart -
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Stadank0
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Re: CR Treatment and Tuning---The home stretch!!
Only pay attention to the last email I sent....much was discovered as I chased my tail all night!!! 
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Stadank0
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Re: CR Treatment and Tuning---The home stretch!!
Well,
Things are chugging along. Stuart is working away on the digital tuning and I'm getting all of the details in order. Cabling, finish, trim,etc....Gonna let Stuart post graphs on the results of course.
In the meantime here's a pic of things as they are..Not a bad place to be. The 2 glass Orbs on the desk are dealing with bounce issues inline with the speakers, but they sure look cool. Love it when you can just go to the store and grab something quick that still looks dope!
And of course the sound is world class!
Things are chugging along. Stuart is working away on the digital tuning and I'm getting all of the details in order. Cabling, finish, trim,etc....Gonna let Stuart post graphs on the results of course.
In the meantime here's a pic of things as they are..Not a bad place to be. The 2 glass Orbs on the desk are dealing with bounce issues inline with the speakers, but they sure look cool. Love it when you can just go to the store and grab something quick that still looks dope!
And of course the sound is world class!
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Waka
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Re: CR Treatment and Tuning---The home stretch!!
Looking very swanky Frank! (see what I did there?) When it's finished you'll have to take some pics from all angles.
Stay up at night reading books on acoustics and studio design, learn Sketchup, bang your head against a wall, redesign your studio 15 times, curse the gods of HVAC silencers and door seals .... or hire a studio designer.
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Stadank0
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Re: CR Treatment and Tuning---The home stretch!!
But it only looks good from that angle!!!! 