Transfering RTA graphic EQ to Crown XTi parametric EQ

[AntonZ]

I have a Behringer DEQ that can do RTA/auto-eq, and also a Crown XTi 1000 with built-in DSP. The Crown can do pretty fancy stuff (especially with the latest versions of the System Architect software), but it's EQ sections are parametric where as the DEQ auto-eq is graphic.

I've been thinking about a way to transfer the graphic auto-eq results from the DEQ into parametric EQ settings on the Crown. Some time ago I realized that photo software allows you to put layers on top of each other, and make the top layers partly translucent. That would allow me, in theory at least, to place the EQ curve from the Crown software on top of a picture of the DEQ screen. Gave it a try today. There is quite some manual work involved - making screenshots, copy/paste, crop, resize, add layers and adjust their order and transparancy. But it does work. Here's some pictures of the process.

Picture of the O10.5 auto-eq. All peaks and valley's beyond 6dB have been brought down to max +- 6dB.


Screenshot of the Crown/Harman "System Architect" software (v1.90), Out-EQ section.


Same, cropped and resized to match the DEQ picture:


Screenshot of high pass filter in System Architect (crossover section).


Same, cropped and resized to match the DEQ picture:


Here's the magic: all put together in one picture, three layers, transparancy set for bottom layers to show through top layers. The white line is the resulting curve from the Crown parametric settings. I added high-pass for speaker protection. This is for 4/5str bass through a single O10.5 (perhaps I should set more aggresive high-pass settings?).



It took several sequences of adjusting parameters, taking screenshots and making the layered version, so this is somewhat time consuming, but it does appear to work quite well. I have not been able to hook it up and play out loud to compare DEQ with Crown EQ, children sleeping in the house and other things to do. Hope to try that later this weekend.

I'm curious to learn what others have come up with for setting parametric EQ to fine tune BFM cabs, either through XTi software or other means of parametric EQ (e.g. Yamaha 01V EQ section).

[gdougherty]

See, I'd just take it all outdoors and run the pink noise out, the RTA in and then use system architect to achieve the desired result with the parametrics. It's nothing particularly magical that the auto-EQ does. Look at your RTA, identify a kind of midline where you want to bring everything to and start adjusting EQ bands. I take care of the biggest bands first with wider parametric filters then start correcting the smaller stuff until I run out of EQ bands or it's looking pretty flat with only very minor dips and rises in a few spots.

I've done what you did, except all within the DEQ, and the results were better manipulating the EQ in relatime with the parametrics. Otherwise you're just guessing and possibly missing out on major undesired manipulations caused by intersecting filters. While you're at it try shooting for something that looks like the equal loudness curves.

[AntonZ]

See, I'd just take it all outdoors

You haven't seen my backyard
It's small, very small. Hard surface, always within 10-15 feet of solid brick walls. Neighbours do not appreciate pink noise sessions, especially of the prolonged and repeated kind.

I've done what you did, except all within the DEQ, and the results were better manipulating the EQ in relatime with the parametrics. Otherwise you're just guessing and possibly missing out on major undesired manipulations caused by intersecting filters. While you're at it try shooting for something that looks like the equal loudness curves.

Thanks, that makes sense to me. I'd have to search for these curves (Sydney probably has them linked somewhere in the Educational Links forum). What I found was that flat sounded very mid heavy to me. E-bass would cut through in a band setting, but music playback did not sound friendly to my ears. I added one filter, mid freq, very very wide Q, and pulled it down quite a bit. Very crude, more finetuning needed, but sounds nice now.

[David Carter]

See, I'd just take it all outdoors

You haven't seen my backyard
It's small, very small. Hard surface, always within 10-15 feet of solid brick walls. Neighbours do not appreciate pink noise sessions, especially of the prolonged and repeated kind.

A brief hijack, if I may... what kind of open space is required to effectively measure and dial in a rig outdoors?

[AntonZ]

You are welcome, it is very much related to the topic.
If I got it right, 50-150 feet of more or less free space in all directions would be nice to make sure you only measure the original source, instead of a mixture of source and cancellations from nearby surfaces. I can imagine a grass field or other soft surface would help, too (as opposed to tiles, concrete or tarmac). I have none of these available, so my RTA results are not reliable.

[WB]

I found 50' works well if the mic is not more than 4 meters from the source.

[David Carter]

And do you set it up just like you would in a venue? Tops on stands 20+ feet apart and subs center clustered on the ground? Where do you place the mic? Front and center on a stand? As you can tell, I'm revealing my complete ignorance, but I'm going to attempt to do this once I get my DR200's finished, so I need to learn.

P.S. If this needs to be a separate thread, I can start a new one.

[WB]

And do you set it up just like you would in a venue?

When I tried that (10 meters) I got a big dip at 700 Hz (I figure ground reflection). There's no point in eq'ing that out because the dip will move in frequency at different distances. Therefore what I like is mids/tweeters full space with the mic fairly close AutoEQ'ed, and subs ground plane, eq'd manually. I remember the first time playing with pink noise and the Phonic PAA3 RTA and being shocked at how the response kept changing as I moved around (outdoors). This is why I believe it's important to only measure the cabinet response and not any boundary reflections.

[AntonZ]

P.S. If this needs to be a separate thread, I can start a new one.

David, I'm as ignorant as you are, or (most probably) worse . I'm learning here too. You are more than welcome to ask further related questions here, as far as I'm concerned.

[BillyG]

And do you set it up just like you would in a venue? Tops on stands 20+ feet apart and subs center clustered on the ground? Where do you place the mic? Front and center on a stand? As you can tell, I'm revealing my complete ignorance, but I'm going to attempt to do this once I get my DR200's finished, so I need to learn.

P.S. If this needs to be a separate thread, I can start a new one.

Do the eq for one side only or you will be reading all kinds of comb filters. I eq my systems outside with one side of the PA. I set the mike at speaker level and about ten feet away. I usually did about three or four readings with my PAA3 and average them. These settings are transfered to your eq system and saved for a starting point for gigs. Or you can do the auto eq thing with a speaker management system and save those settings. As it turned out, most gigs we didn't take time to eq the rooms so we just went with the speaker correction eq's and it seemed to work.

[David Carter]

Do the eq for one side only or you will be reading all kinds of comb filters. I eq my systems outside with one side of the PA. I set the mike at speaker level and about ten feet away. I usually did about three or four readings with my PAA3 and average them. These settings are transfered to your eq system and saved for a starting point for gigs. Or you can do the auto eq thing with a speaker management system and save those settings. As it turned out, most gigs we didn't take time to eq the rooms so we just went with the speaker correction eq's and it seemed to work.

This sounds like you were only measuring your tops. Is that correct? If so, did you do something else for subs or did you not attempt to EQ your subs at all?

[BillyG]

Do the eq for one side only or you will be reading all kinds of comb filters. I eq my systems outside with one side of the PA. I set the mike at speaker level and about ten feet away. I usually did about three or four readings with my PAA3 and average them. These settings are transfered to your eq system and saved for a starting point for gigs. Or you can do the auto eq thing with a speaker management system and save those settings. As it turned out, most gigs we didn't take time to eq the rooms so we just went with the speaker correction eq's and it seemed to work.

This sounds like you were only measuring your tops. Is that correct? If so, did you do something else for subs or did you not attempt to EQ your subs at all?

That's correct. I eq or auto eq from the crossover on up. I've done a separate eq for the subs.

[David Carter]

I've done a separate eq for the subs.

Would you mind sharing your process for EQ-ing your subs?

[BillyG]

I've done a separate eq for the subs.

Would you mind sharing your process for EQ-ing your subs?

I did it in the same maner with a PAA3 setting the mic about ten feet away and an inch off the ground. This was done about a hundred feet away from my house on the lawn. I used a about half power to get a good reading. I remember when I first built a pair of Tuba 24's I didn't have any way to get a rta reading so I used Bill's spl charts and set the 31 band eq like a mirror image. Were there was a 3 db gain I pulled down 3db on the appropriet slider and so on. It worked OK for a few gigs. It's amasing that you can get good sound without all of the bells and whistles.

[David Carter]

I've done a separate eq for the subs.

Would you mind sharing your process for EQ-ing your subs?

I remember when I first built a pair of Tuba 24's I didn't have any way to get a rta reading so I used Bill's spl charts and set the 31 band eq like a mirror image. Were there was a 3 db gain I pulled down 3db on the appropriet slider and so on.

Yes, that's what I've done until now with all my BFM builds. I'm just looking to take the next step. Thanks for sharing.