First shot at REW w/graphs

**sickboy013** · **04-28-09, 02:17 PM**

Hey guys, just got REW up and running and ran a couple of graphs. I don't have a ton of time this morning, but here's what I came up with.

This is my digital RS SPL meter measuring my premier acoustics pa-120 sub. I ran a sweep from 15hz to 120hz with the level set at -12db and 1m set on the length in the measure section. I had the rs cal file loaded and calibrated to 75db on my spl.

This first one is the sub corner loaded (right corner).

The second is the sub on the left side of my entertainment center.

What can you guys tell me about what you think about these graphs. Hopefully I have everything set up right. If not I'll have to mess around with it later.

**Wayne A. Pflughaupt** · **04-28-09, 03:17 PM**

Measurements look good (as in everything you've done with REW is functioning correctly). Rescale the graphs to our standard, 45-105 dB vertical and 15-200 Hz horizontal. There's a graph axis icon towards the top right of the REW window that will let you set the parameters.

Regards,
Wayne

**brucek** · **04-28-09, 03:26 PM**

Quote:

I ran a sweep from 15hz to 120hz

Measure subs with a setting of 0Hz-200Hz and then set the graphs (as Wayne says) to the standard Vertical graph axis of (45dB - 105dB) and the Horizontal graph axis of (15Hz - 200Hz) using the Graph Limits button in the top right corner of REW.

Your response looks pretty good though....

brucek

**sickboy013** · **04-28-09, 04:36 PM**

Quote:

Wayne A. Pflughaupt wrote:

Measurements look good (as in everything you've done with REW is functioning correctly). Rescale the graphs to our standard, 45-105 dB vertical and 15-200 Hz horizontal. There's a graph axis icon towards the top right of the REW window that will let you set the parameters.

Regards,
Wayne

Thanks,

I'll rescale everything and run some more sweeps.

Quote:

brucek wrote:

Measure subs with a setting of 0Hz-200Hz and then set the graphs (as Wayne says) to the standard Vertical graph axis of (45dB - 105dB) and the Horizontal graph axis of (15Hz - 200Hz) using the Graph Limits button in the top right corner of REW.

Your response looks pretty good though....

brucek

Thank you, I'll run some more sweeps tomorrow and change the graph axis.

What do you guys think from looking at the preliminary graphs as far as placement goes? Would it be better to have it corner loaded or in the second spot. A BFD is good for taming peaks so would it be beneficial to have it corner loaded and equalize it with a BFD?

**brucek** · **04-28-09, 05:12 PM**

The graph on the 'left side' looks pretty good. I'd probably go with that...

brucek

**sickboy013** · **04-28-09, 05:24 PM**

Quote:

brucek wrote:

The graph on the 'left side' looks pretty good. I'd probably go with that...

brucek

Thanks for your help brucek. Sorry about the noob questions, I haven't done anything like this before. I was thinking about the 'left' one. I do like the corner loading, but it has a lot more peaks and nulls, and haven't really tried the 'left' side with any listening material. Would it be good to take measurements from 3 points (i.e. the center, right, and left sides of the listening position) once sub placement has been decided and combine them to ensure good bass all over the listening position?

**brucek** · **04-28-09, 05:50 PM**

Quote:

Would it be good to take measurements from 3 points (i.e. the center, right, and left sides of the listening position) once sub placement has been decided and combine them to ensure good bass all over the listening position?

I guess that depends on how much you care what those positions hear. The wider the area you are trying to achieve a good response, the more compromise each position usually takes.

brucek

**sickboy013** · **04-28-09, 06:41 PM**

Quote:

brucek wrote:

I guess that depends on how much you care what those positions hear. The wider the area you are trying to achieve a good response, the more compromise each position usually takes.

brucek

Yeah that makes sense. I'll stick with the one in the middle, because now that I actually think about it, the bass doesn't differ too much in the other positions. It's the only couch/seating position in the room.

**sickboy013** · **04-29-09, 02:45 PM**

Here are the graphs again. I fixed the graph axis. I haven't had time to run any more tests so I'll have to wait for another day or so. But here are these posted again.

Here's the right corner loaded graph.

And the sub on the left side of my entertainment center.

**sickboy013** · **05-02-09, 12:41 PM**

I ran a couple of other tests with REW and got a little different results than I did the first time. This time I ran the sweep from 0-200hz. I also generated some waterfalls of the sweeps, what can you tell me about those?

Now here's the thing. I listened to a couple of 'test' scenes from movies with the sub in both positions. I know having the sub on the left side of my entertainment center yields a flatter response, but I like the sound of it being in the right corner of my room (not so flat response).

Now my question is, is there downside to keeping it in the corner? And would building a single basstrap to put in the corner behind the sub do anything or would it be a waste of time?

Left side w/waterfall

Right corner w/waterfall

**brucek** · **05-02-09, 01:34 PM**

Quote:

but I like the sound of it being in the right corner of my room (not so flat response).

Now my question is, is there downside to keeping it in the corner?

No, you like the sound of the 48Hz peak it develops when it's there. No problem with that, other than it will tend to overwhelm the sound of 20Hz signals, as opposed to a flatter response.

brucek

**Wayne A. Pflughaupt** · **05-02-09, 09:31 PM**

Quote:

sickboy013 wrote:

And would building a single basstrap to put in the corner behind the sub do anything or would it be a waste of time?

Bass traps don't work down that low - at least nothing that's a reasonable size.

Regards,
Wayne

**sickboy013** · **05-02-09, 11:22 PM**

Quote:

Wayne A. Pflughaupt wrote:

Bass traps don't work down that low - at least nothing that's a reasonable size.

Regards,
Wayne

Thanks Wayne, I was wondering if it would be worth my time and trouble to do that. Would adding a BFD be beneficial to my situation? (I'm gonna cross post this question in the BFD forum)

It's still bugging me about the whole location thing. I don't know why though. It's like I think I'm doing something wrong by keeping it in the corner! I'm gonna make myself crazy worrying about this! lol!

**sickboy013** · **05-02-09, 11:25 PM**

Quote:

brucek wrote:

No, you like the sound of the 48Hz peak it develops when it's there. No problem with that, other than it will tend to overwhelm the sound of 20Hz signals, as opposed to a flatter response.

brucek

Yeah I do like it, to me it feels like it fills the room more than when it's on the left side of my ent. center. I'm just stuck debating if I want to go the proper technical way or just leave it how it is.

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