BFD | Electronic Equalization Devices

**Lonely Raven** · **10-06-08, 03:13 PM**

I'm reading through here to get some tips and ideas on how to possibly integrate the BFD into my budget HT setup...and most of the descriptions and guides here seem biased to bass management.

Is there a reason why people wouldn't be using the BFD for full spectrum EQ?

I ask, because I have some broad band dips in the seating position that I haven't been able to resolve with speaker placement (I can't move them too much), and I happen to be looking at tweaking the sub a little bit anyways.

My old Yammaha receiver happens to have an EQ/Procesor loop, so I could loop the BFD in there. But I'm not sure if that's the best way to do full range EQ with a sub.

Thoughts?

**Wayne A. Pflughaupt** · **10-06-08, 08:04 PM**

Some people have complained that the BFD added undesirable artifacts, but it can't hurt to try. One thing I did notice when connected it to my system once was that it adds some background noise with the back panel switches in the +4 position. That might not be audible with regular level settings, however.

Overall, if you have a decent system I don't think I'd be inclined to add a $99 equalizer to it. It's probably worthwile to move up to the FBQ2496 for full-range use, or get some good-quality analog models.

Also, regarding the broad dips you mentioned, I hope they aren't too deep. Typically you don't want aggressive equalizing on the main channels. A full-range REW graph would show if you're a candidate for equalizing.

Regards,
Wayne

**Lonely Raven** · **10-06-08, 08:47 PM**

Quote:

Wayne A. Pflughaupt wrote:

Some people have complained that the BFD added undesirable artifacts, but it can't hurt to try. One thing I did notice when connected it to my system once was that it adds some background noise with the back panel switches in the +4 position. That might not be audible with regular level settings, however.

Overall, if you have a decent system I don't think I'd be inclined to add a $99 equalizer to it. It's probably worthwile to move up to the FBQ2496 for full-range use, or get some good-quality analog models.

Also, regarding the broad dips you mentioned, I hope they aren't too deep. Typically you don't want aggressive equalizing on the main channels. A full-range REW graph would show if you're a candidate for equalizing.

Regards,
Wayne

Thanks again for your help, Wayne. While old, it *is* a $1500 receiver (back in the day). So I do get your point about dropping a $99 EQ in the path.

Now that you mention it, I probably have some old 31 band EQ units left over from my home studio days. Maybe I'll pop one of those in the loop and see what happens.

Here is the only full range graph I have right now.

I'm still learning REW and not sure if I'm getting the most out of it yet. I did some sub tests tonight with 3 very large bass traps, only to see *very* slight change in the graph...so I'm not sure if it's user error, or maybe I was expecting too much from these three absorbers.

**Wayne A. Pflughaupt** · **10-07-08, 08:38 PM**

Quote:

I'm still learning REW and not sure if I'm getting the most out of it yet. I did some sub tests tonight with 3 very large bass traps, only to see *very* slight change in the graph...so I'm not sure if it's user error, or maybe I was expecting too much from these three absorbers.

One of the functions of bass traps is to reduce low frequency ringing (aka extended signal decay times). You might notice a "before and after" difference using REW's waterfall graph feature.

Regards,
Wayne

**Lonely Raven** · **10-08-08, 12:17 AM**

Quote:

Wayne A. Pflughaupt wrote:

One of the functions of bass traps is to reduce low frequency ringing (aka extended signal decay times). You might notice a "before and after" difference using REW's waterfall graph feature.

Regards,
Wayne

Ahh, I've not gotten that far with REW. I need to figure out how to use the Waterfall Graph portion. Because I do hear a slight difference in the bass, just not as much as it was with a (much) smaller, rectangle shaped room.

I might even move all 400lbs of absorbers and retest if need be. But I saved all my results so I don't think that's necessary unless I did the measurements wrong.

**Wayne A. Pflughaupt** · **10-08-08, 05:13 PM**

Quote:

Ahh, I've not gotten that far with REW. I need to figure out how to use the Waterfall Graph portion.

Nothing to it.

Just click the "Waterfall" tab at the top of the REW graph after you've made your measurement. When the window opens, click the "Generate Waterfall" icon.

Regards,
Wayne

**brucek** · **10-08-08, 06:38 PM**

Be sure to use 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.

Also be sure to use LOG mode rather than LIN mode using the Freq Axis button in the top right corner of REW.

**Lonely Raven** · **10-08-08, 06:46 PM**

Quote:

brucek wrote:

Be sure to use 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.

Also be sure to use LOG mode rather than LIN mode using the Freq Axis button in the top right corner of REW.

Thanks. That was part of what I wasn't sure of.

Hopefully you guys can help me read it then, as I'm not sure what I'm looking at.

I'll upload the graphs later tonight.

**bfrank1972** · **10-09-08, 08:51 AM**

Just curious - what sort of artifacts (other than general noise) were people complaining about?

I have a DEQ2496 for my two mains and the BFD for the sub - I was thinking about using the 2nd un-used chanel for my center. I thought it might be worth a shot for HT as my center vocal response seems to be a bit lumpy and might not be so sensitive to any artifacts introduced by the BFD. Thoughts?

**Lonely Raven** · **10-09-08, 09:04 AM**

I like the idea of having some EQ for the center. Thanks for helping me spend more money! LOL

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