Graphs; Recommendations? House curve?

**jschaefer7406** · **02-22-09, 11:42 PM**

Hello again,

Set up my BFD today and would like some input. Here is what I started with:

Front subs:

Rear sub:

Through moderate low boosting (I know it's usually not recommended, but the concensus seems to be that it's okay if it actually helps), I was able to get it truly flat:

Front result:

Rear result:

Now, as most will agree, it sounds lacking. Should I apply a house curve? Is my boosting okay, given the graphs to show the result? Both amps are at only 1/2 volume, so headroom should be okay? Please advise.

Thanks,

Joe

P.S. - I calibrated the RS digital SPL meter in REW, but did not load the correction file. Is this accurate (being I compensated it in REW), or will I have to re-run it with the correction file loaded?

**Wayne A. Pflughaupt** · **02-23-09, 12:58 AM**

Please re-scale your graph for a 15-200 Hz horizontal and 45-105 dB vertical axis. You can do that by clicking on the "Graph Limits" icon in the upper right corner.

Quote:

Should I apply a house curve? Is my boosting okay, given the graphs to show the result? Both amps are at only 1/2 volume, so headroom should be okay?

Any equalizing comes at the expense of headroom. Whether or not you have enough left - you'll find that out once you start using the system. The tell-tale sign will be nasty noises from the sub drivers as they bottom out; however, some powered subs have built-in limiters to prevent this. In that case, you'll notice that bass levels no longer increase in volume with the rest of the system.

Regards,
Wayne

**jschaefer7406** · **02-23-09, 01:26 AM**

Wayne,

Thanks for the reply. I did fix the graph scales in the original post. Do you personally think I should try for a house curve? I had to boost the low end and cut the higher stuff already, so I'd have to do that even more to apply a house curve. I think it may sound better for music though. Thoughts? Any thoughts on whether I should load the correction file, or is it enough simply to calibrate the SPL in REW?

Thanks,

Joe

**brucek** · **02-23-09, 08:17 AM**

Quote:

Any thoughts on whether I should load the correction file, or is it enough simply to calibrate the SPL in REW?

The results are meaningless without the correction file. The calibrate SPL has nothing to do with correction except to balance levels between the real meter and the REW meter.

Load the correction file and apply the changes to the mdat files. Use the Impulse Response Windows 'Apply Windows' button after loading.

You will then need to redo all your filters.

brucek

**jschaefer7406** · **02-23-09, 12:35 PM**

Brucek,

Not to sound terribly stupid or anything, but what does the impulse resonse application tell me? I hit "apply windows" as suggested (left all defaults in place, jut applied). I searched the help files in REW, but it wasn't in depth about using the .cal files. Also, the .cal file for my meter placed the black line on the graph. What do I follow now? Can you look at my modified graph and advise?

Thanks,

Joe

**brucek** · **02-23-09, 01:27 PM**

Load the mdat file that was created without a calibration file.

Load the calibration file.

Click IR Windows.

Click Apply Windows in the IR WIndows popup while watching the response graph to see the change.

The graph will now reflect the results with the Calibration file.

Save the new mdat file.

brucek

**jschaefer7406** · **02-23-09, 02:36 PM**

Brucek,

Thanks for the info. I guess what I'm asking is this. Once I load the calibration file and apply windows, I will likely start over. What type of curve am I after? Should I follow the original blue target line or the black SPL calibration line? Does this mean that there is already a house curve built into my "after" graph (since I didn't use the .cal file)?

Sorry for so many questions, just want to get this right,

Joe

**thewire** · **02-23-09, 03:53 PM**

Quote:

jschaefer7406 wrote:

Brucek,

Thanks for the info. I guess what I'm asking is this. Once I load the calibration file and apply windows, I will likely start over. What type of curve am I after? Should I follow the original blue target line or the black SPL calibration line? Does this mean that there is already a house curve built into my "after" graph (since I didn't use the .cal file)?

Sorry for so many questions, just want to get this right,

Joe

IMO simply equalizing to a non calibrated mic is not getting anywhere near anything appreciable to a house curve. The difference is way to small.

**Wayne A. Pflughaupt** · **02-23-09, 05:47 PM**

Quote:

Thanks for the info. I guess what I'm asking is this. Once I load the calibration file and apply windows, I will likely start over. What type of curve am I after? Should I follow the original blue target line or the black SPL calibration line? Does this mean that there is already a house curve built into my "after" graph (since I didn't use the .cal file)?

The blue line is the Target Curve – that’s the one you’re concerned about. It appears that your house curve has been added to the Target, so you’re in business. Once you load the mic calibration file, your graphs will be correct, even the previous ones, provided you saved them.

Regards,
Wayne

**jschaefer7406** · **02-23-09, 06:01 PM**

Wayne,

As always, thanks for the info. The graph in post #5 is the existing graph with mic calibration added. When I added the calibration file, the graph itself didn't change (it just added that black curve to the mix). You mentioned that once I loaded the calibration file they would be correct. Can you elaborate, since the graph is the same even with the file added?

Thanks,

Joe

P.S. - Reason I am asking all of this is that it sounds sort of dead on music (you have to really listen to pick out the sub material. I prefer them kind of hot in the low end. I don't know if I did something wrong, or if this is how a balanced system is meant to sound...

**brucek** · **02-23-09, 06:14 PM**

Quote:

since the graph is the same even with the file added?

Then you didn't apply the calibration file to the old mdat file. It would not be the same.

brucek

**jschaefer7406** · **02-23-09, 09:11 PM**

Brucek,

I did exactly what you instructed. The front result graph in post #1 (before .cal) looks exactly the same as the graph in post #5 (after applying calibration and impulse windows as instructed). Am I missing something?

Thanks,

Joe

**brucek** · **02-23-09, 11:06 PM**

Quote:

Am I missing something?

Yep, I just don't know what it is.

If you examine the Radio Shack digital meters calibration file at 20Hz for example, you can see it will add +6.5dB to the signal from the meter at that frequency. So, you can see how it would be impossible for the graph not to change at all.

brucek

Advertisement