Just a quick question on the Toslink connection for MINIDSP 4X2HD

[everettT]

Plus or minus how many db is acceptable from within lets say 10 db. Are we looking at something like +-5db flatness?

In room that's very acceptable. You should get the placement that takes care of the suckout and then play with the transform till you have it dialed in. Make sure you take and save each measurement so you can overlay.

Also always true to cut EQ not boost, but that will be after

 

[everettT]

Post the graph at 1/12 if you get a second. It's more meaningful when you do it higher, as it shows the detail. I just want to see it smoothed

 

[everettT]

Also in terms of looking at the transform, lower is easier as you not making fine frequency adjustments

 

[moves]

Post the graph at 1/12 if you get a second. It's more meaningful when you do it higher, as it shows the detail. I just want to see it smoothed

Will do but I've read that subwoofer signals don't need smoothing or only very little.

 

[moves]

Also in terms of looking at the transform, lower is easier as you not making fine frequency adjustments

Not sure what you mean? What is a transform? Lower meaning lower in +- X db?

 

[everettT]

Not sure what you mean? What is a transform? Lower meaning lower in +- X db?

The Linkowitz transform. As for lowering I was referring to the graph resolution.

 

[moves]

Here is the overlay with 1/12

12

 

[everettT]

Your not running the crossover engaged are you?

 

[moves]

Your not running the crossover engaged are you?

it is crossed over at 80 Hz in the AVR. Bypassed in the MiniDSP. Why what should I have it at?

 

[moves]

Here are some measurements with various mic locations. The problem seems to be consistent.

Here is another one where I set the sweep range from 10 - 80 Hz... previous graph was from 10 - 125 Hz... Since the crossover is set at 80Hz, I didn't see the reason to include the sweep past 80 Hz.

Here is a full range measurement with main speakers smoothed to 1/12... there are dips but not sure how bad they are.

Here it is smoothed to 1/3

 

[everettT]

Have you tried moving the sub yet or just the mic a few feet? Also with the linkowitz transform you should be a little further in the teens. But again your headed in the right direction

 

[moves]

I tried moving the sub around but I think it's best where it is. So lower the Lt from 18hz to what?15?

Also, when I boost a frequency let's say @ 45hz by 10 db the whole graph jumps up by 10db...I thought it only applies to whatever Freq I specify.

 

[everettT]

I tried moving the sub around but I think it's best where it is. So lower the Lt from 18hz to what?15?

Also, when I boost a frequency let's say @ 45hz by 10 db the whole graph jumps up by 10db...I thought it only applies to whatever Freq I specify.

Cut dont boost, except in small dbs. What do you mean the sub is best where it is? Did you play with room simulation in REW.

 

[moves]

Cut dont boost, except in small dbs. What do you mean the sub is best where it is? Did you play with room simulation in REW.

Oh so to raise a frequency I should go - 10db gain instead of +10 db gain? I tried another spot and also crawled and I think the sub "is best where it is". back right corner. unpainted pdf square on the right side. See pic below:

I haven't done the room simulation nor the auto EQ in REW. I will research it on how do implement it.

 

[everettT]

Yes your lower to even out. As it takes tremendous amount of power raise eq and that should be reserved for the biquads like the transform. Your driver will take a boat load of power. Your amp will run out before the driver does with heavy EQ. Dont use the auto eq, use the room simulation. You dont want to use two different types of EQ

 

[William Lemmerhirt]

I tried moving the sub around but I think it's best where it is. So lower the Lt from 18hz to what?15?

Also, when I boost a frequency let's say @ 45hz by 10 db the whole graph jumps up by 10db...I thought it only applies to whatever Freq I specify.

The reason is because at 45hz there’s a room mode there. That means even though the subwoofer is outputting 45hz, the room is cancelling 45hz at the LP. Nulls can’t be boosted by eq since it’s a function of the room. So if you boost 45hz by 10, everything else around it will go up too since it’s not a notch filter acting only on one frequency. Imagine a “V” shape. The problem is, 45hz won’t go up unless you move the subwoofer, or the LP and the reason built in sub eq’s only allow for about 3db boost is because you can blow up your stuff by over boosting frequencies that won’t change. You can pull peaks down however, and I would focus on that.
Also, could you set you right side graph limit to 200hz? That will show the graph more like how you’d hear it.

 

[William Lemmerhirt]

Oops. I see you changed it to 200.
This is kinda what I meant by the “V” shape.

 

[moves]

The reason is because at 45hz there’s a room mode there. That means even though the subwoofer is outputting 45hz, the room is cancelling 45hz at the LP. Nulls can’t be boosted by eq since it’s a function of the room. So if you boost 45hz by 10, everything else around it will go up too since it’s not a notch filter acting only on one frequency. Imagine a “V” shape. The problem is, 45hz won’t go up unless you move the subwoofer, or the LP and the reason built in sub eq’s only allow for about 3db boost is because you can blow up your stuff by over boosting frequencies that won’t change. You can pull peaks down however, and I would focus on that.
Also, could you set you right side graph limit to 200hz? That will show the graph more like how you’d hear it.

Oh wow that is a huge tip. I thought I would be able to lower that null.. so I think I get it. Don't worry about flattening out the nulls just try to lower the peaks. To do this, just decrease the gain in PEQ at the frequency that I need?

What variation should I be aiming for? +-5 db flatness on the graph? What de should I be outputting my sweeps at? (90db?)

I can try to move the subs around some but they are so heavy lol. I crawled and found that it sounds best in the corner. I can try again, however.

 

[everettT]

Dont over eq. Your room will very rarely give a flat responce. As I mentioned you cut to even out. After you get the target low end achieved, 5he work on placement and trims.

 

[moves]

What db am I aiming for?

What type of filter should I use? Low shelf high or peak? I played around with it and peak seemed best. But is it appropriate?