Is there a thread that tells you what the results on REW mean and how to correct the room from an ..

**JimP** · **02-08-09, 03:06 PM**

I was wondering if I was going to run out of space before getting all of my title in the block.

This is the situation. I have REW working but other than the frequeny response chart and using an equalizer, I'm pretty lost. What I'd like to do is to be able to read the other graphs and know what to do to correct the room using acoustical panels. Are there any threads that are specifically a how to interpret REW charts and what to do to correct problems.

**brucek** · **02-08-09, 03:26 PM**

Quote:

Are there any threads that are specifically a how to interpret REW charts and what to do to correct problems.

I don't think so. The only guides we have are centered around getting REW to work.

Mostly, members just post their specific questions and someone will answer them...

brucek

**JimP** · **02-08-09, 03:36 PM**

Thanks

**JimP** · **02-10-09, 04:28 AM**

Just as a suggestions, anyone with the energy to do a "how to guide to interpret REW graphs" and recommend what needs to be done to improve the sound in a room given these graphs would be granted "King Geek" status.....not to mention that it would be very helpful to the rest of us.

**Sonnie** · **02-10-09, 09:00 AM**

If I was not right in the middle of constructing our new HT room, I would ride up to Wetumpka and help you. I bet Rodny would be willing to ease over your way and help you.

A "how to interpret" guide might not be a bad idea either, although it seems like nearly every thread about REW graphs is somewhat of a "how to interpret and what to do" type thread.

Do you still have your SMS-1? REW works along the same premise.

**JimP** · **02-10-09, 09:34 AM**

Hi Sonnie,

New HT room? Wanna see.

I still have the SMS-1 and have REW working on a dedicated laptop. I basically use these to view response variances when changing subwoofer distance and setting on the sub itself. I don't route the sub signal through the SMS-1 for EQ.

I recently bought some accoustic panels and have been moving them in and out of the room with what looks like very little differences in plots yet more difference in how it actually sounds. In the end, what sounds best will prevail but I just want to be sure that I'm getting as close as "technically" possible according to REW.

I agree that you can get bits and pieces from the REW threads, but its so scattered out.

Maybe you can run a 1 day seminar in your new home theater once its ready????

**thewire** · **02-10-09, 10:09 AM**

Quote:

JimP wrote:

Just as a suggestions, anyone with the energy to do a "how to guide to interpret REW graphs" and recommend what needs to be done to improve the sound in a room given these graphs would be granted "King Geek" status.....not to mention that it would be very helpful to the rest of us.

I have been considering treating a normal room with less problems as a learning expeience for myself. I have an empty room that is the perfect candidate, but I have one room treatment that needs ordering before I do that.

**JimP** · **02-10-09, 10:32 AM**

Define "normal".

I'm thinking about doing an outline of what someone with very little knowledge on acoustics and REW graph reading would want to know. Starting off with taking room readings and correlating room modes using Gold's room mode calculator.

**brucek** · **02-10-09, 11:04 AM**

I don't want to discourage you, but I think the effort required would have very little payback.

Everyone's case is so different that interpretation requires individual comment from multiple posters.

There are no hard and fast rules. You can't get any two people to agree. Everyone, including 'experts', have differing opinions on interpretation of graphs.

I think we've done a fairly decent job of creating the guides on the nuts and bolts of how to use REW and create the graphs. There's very little to disagree about in that regard. But to create a guide on interpreting graphs? I don't see that it would solve anyone's specific problems. The room mode calculators are such a rough approximation for a perfect world that I almost never recommend them.

I wish I could be more positive about the idea, but....

brucek

**thewire** · **02-10-09, 11:24 AM**

The possible test specimin features optimal room size ratio, non insulated walls, and features including for those of high WAF.

**JimP** · **02-10-09, 03:16 PM**

Quote:

brucek wrote:

I don't want to discourage you, but I think the effort required would have very little payback.

Everyone's case is so different that interpretation requires individual comment from multiple posters.

There are no hard and fast rules. You can't get any two people to agree. Everyone, including 'experts', have differing opinions on interpretation of graphs.

I think we've done a fairly decent job of creating the guides on the nuts and bolts of how to use REW and create the graphs. There's very little to disagree about in that regard. But to create a guide on interpreting graphs? I don't see that it would solve anyone's specific problems. The room mode calculators are such a rough approximation for a perfect world that I almost never recommend them.

I wish I could be more positive about the idea, but....

brucek

I take it then that you aren't interested in organizing it?

Sounds like I don't know enough to even know that it doesn't work in the manner I would hope.

As an example, lets say that there is a significant dip at 80hz. I'd say that the first step should be to running their speakers as large and their subwoofer off to determine if they have their speakers out of phase or if its something else....else meaning a room mode that can be tested by (offer a test).

**robbo266317** · **02-10-09, 03:40 PM**

How about posting a graph with the room empty to see how well it ties in with the theoretical nodes?
Or has the furniture been moved back in already?

**thewire** · **02-10-09, 04:20 PM**

Quote:

robbo266317 wrote:

How about posting a graph with the room empty to see how well it ties in with the theoretical nodes?
Or has the furniture been moved back in already?

The room is empty because the wall on the right in the photo with the dresser is being removed, then a kitchen added using the exsisting plumbing from the older kitchen bellow. We don't use that room for anything except for storing things being moved around from what is the left side of the house, to the right side of the house with the garage or bedroom which is only accessed by going outside. There is no door from the garage yet, but that is on the list of things to do soon. You want a graph to see the accuracy of the room mode calculator? You want the subwoofer in the best position or a position for the theoretical best placement in an ideal situation? My subs are suppossed to be designed for a room size like this, and have usuable response up to 300Hz. They roll off at 30Hz with in-room 18Hz, but I have modified them for use with an external amplifier.

**thewire** · **02-10-09, 04:35 PM**

To measure the modes I would just place the mic in the right corner and the sub in the back left, is that what you wanted to look at?

**thewire** · **02-10-09, 05:18 PM**

I started with an output level of 5, but had to turn it down for 3 which gave me this 88dB target while input VU and output was -18. I measured the corner with the sub in the opposite corner. I left the room while REW took the sweep. This is without a crossover measured 0Hz - 200Hz. The mic was at ear level while standing.

**JimP** · **02-10-09, 05:25 PM**

Quote:

thewire wrote:

To measure the modes I would just place the mic in the right corner and the sub in the back left, is that what you wanted to look at?

Is that the correct mic position?

**thewire** · **02-10-09, 05:38 PM**

Quote:

JimP wrote:

Is that the correct mic position?

It's suppossed to be in the upper right corner but I don't remember exactly how close so I just put it at ear level. The sub was correctly spaced from the wall for the ports and was not positioned at equal distance from the left wall. The mic was kind of hanging out into the room slightly also. I tied it to a facial mask and tacked it to the wall. If anyone has suggestions the correct distance to measure I will do that instead, but I think this one looks pretty close to the predicted room modes and you can see the 70Hz ceiling mode is effected.

**robbo266317** · **02-10-09, 05:50 PM**

That should do it. I'm curious as to how much is visible in REW.
I was going to try it myself when the new house was built. However, with that on hold with the company going into administration, I cannot try it without clearing all the furniture out of one room - too much hassle.

**robbo266317** · **02-11-09, 03:19 PM**

Thanks for posting the plot.
Your room is close to one of the reccomended ratios. Was that by accident or design?
It's strange though, I had expected to see the 40 Hz resonance more & I assume the long ? (600ms) delay is because the room is bare.

**thewire** · **02-11-09, 05:18 PM**

Quote:

robbo266317 wrote:

Thanks for posting the plot.
Your room is close to one of the reccomended ratios. Was that by accident or design?
It's strange though, I had expected to see the 40 Hz resonance more & I assume the long ? (600ms) delay is because the room is bare.

That's probobly the resonance of the room being the longest distance therefore it's called the rooms resonance. Those are always very long, and it would take lots of trapping to get that down. Our home was built with a sketch, same with the remodel. I don't think the room size was intential, but I knew by looking at it was a good ratio before I measured it for this thread. You don't really have to be that exact for it to be good, just close.

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