EQ Question: Are My Ears "Messed Up"

[doncolga]

Thought I'd share these links for the RoomEQWizard steps 1-3. I should be able to do this. Do these seem pretty straight to you all?

Step 1 Calibration
http://www.youtube.com/watch?v=21wUsNfF2Lw

Step 2 Check Levels
http://www.youtube.com/watch?v=XmV0SiGFaNQ&NR=1

Step 3 Measurements
http://www.youtube.com/watch?v=jkj_VMB9m4E&NR=1

[BrentEvans]

-those steps are geared more toward measuring your room or cabs. After you get your rig Calibrated, you'll want to use the rta function with pink noise to get a look at what your cabs are doing. If you dont already have the latest version (v5.) You want to download it. It can genetate the pink and do the rta simultaneously. While watching yhe rta, adjust your eq filters to flatten out the response to +/-3db or less. Set up outside and away from obstructions to do this for your baseline.

[doncolga]

-those steps are geared more toward measuring your room or cabs. After you get your rig Calibrated, you'll want to use the rta function with pink noise to get a look at what your cabs are doing. If you dont already have the latest version (v5.) You want to download it. It can genetate the pink and do the rta simultaneously. While watching yhe rta, adjust your eq filters to flatten out the response to +/-3db or less. Set up outside and away from obstructions to do this for your baseline.

I do have Version 5, so if I'm able, I may give that a whirl this morning when I get back in from church. I've never seen more than 3 bands of EQ on the DCX, but I'll certainly check again. At this point the big thing is to just get a measurement anyway.

Thanks!

Donny

[doncolga]

For testing, I was going to put the speakers on stands at or a little above head height, since that's where I'll be playing with them. Should I put the mic about 15-20 feet out front in between the two?

Thanks!

Donny

[BrentEvans]

Use only one speaker, place it at it's normal height off the ground, and the mic on a stand on axis at about 15-20 ft. This will minimize interactions, and mimic a live environment setup closely. You don't use the second speaker simply because the interaction patterns will be different at each venue, but if you get one flat, the other will be too. Then, at the venue, if you need to make a small adjustment to account for interaction with each other and the room, you do that on your graphic EQ.

Note that this isn't the industry standard way to measure a cab.... so your results may not match the published charts perfectly... but who listens in an anechoic chamber, or in any of the other perfect situations (AKA strange predicaments) that speakers are placed in for measurement?

[doncolga]

OK...I just took this with the Behringer ECM800 measurement mic going flat into my board, from there via USB to RoomEQ Wizard, set to RTA 1/12 octave, sending full range pink noise with no EQ to the Otops only. I meant to post as 1/12 octave but had trouble bringing that version back. Do those setting sound right and does the chart look reasonable?

Thanks!

Donny

UPDATE: This is not right...checking again...

[doncolga]

This is the corrected take. The previous one was using the wrong mic. How does this look?

Thanks,

Donny

[BrentEvans]

Looks close. Reduce the range so you can see vertically better... You want to be able to resolve 3db or less

[doncolga]

Looks close. Reduce the range so you can see vertically better... You want to be able to resolve 3db or less

Here's another one...not sure this is what I should be getting...

[Bill Fitzmaurice]

Here's another one...not sure this is what I should be getting...

That's OK, but smooth to 1/6 octave, that's the industry standard as you can't hear 1/12 octave anyway. To see where to set your EQ use 1/3 octave with a 31 band, 1/2 octave with a 15 band.

[DaveK]

... you can't hear 1/12 octave anyway

Could you elaborate on this, Bill? 1/12 octave is one semi-tone and obviously most people can hear the difference between C and C#.

[Bill Fitzmaurice]

... you can't hear 1/12 octave anyway

Could you elaborate on this, Bill? 1/12 octave is one semi-tone and obviously most people can hear the difference between C and C#.

There's a big difference between hearing a semi-tone that's 1/12 octave wide and being able to pick out a response peak or dip that's 1/12 octave wide amongst the remaining 119 odd 1/12 octave wide bands that comprise a full range signal. When you shift pitch by one note you don't shift one 1/12 octave bandwidth signal, you shift all 120 of them in a ten octave bandwidth.

[doncolga]

This is another test of one OT12 with pink and sine sweeps. The last measurements inadvertently had the crossover settings on...don't know if that makes any difference or not...

Does is matter which one I use? I guess the pink noise I could run constant and adjust the EQ until its flat?

Thanks!

Donny

[doncolga]

I tested my commercial top and it wasn't as flat as the spec's say, but I'm sure I'm not using exactly the same procedures either. It was interesting to compare the two.

I notice the db's on my charts are alot lower than other's I've seen. Are those others pretty much blasting? I didn't want to drive my neighbors nuts today...even though we are out in the country...

[BrentEvans]

I notice the db's on my charts are alot lower than other's I've seen. Are those others pretty much blasting? I didn't want to drive my neighbors nuts today...even though we are out in the country...

Unless you calibrate with an SPL meter, don't worry about the levels that are reported. You're not measuring sensitivity anyway, you're measuring response.