question on REW vs DEQ2496 BW(oct) units

[ssabripo]

guys,
if you notice, the REW v4.0 filter parameters are either in Gain and BW/60 (when using BFD mode) or BW(Oct) when using FBQ mode. The DEQ2496 is also in BW(Oct) mode.

one curious thing I noticed last nite when I entered a couple of new filter settings, is that the range on the DEQ's BW(Oct) is from like 10 to 1/10, where as in REW, the units start in default at 1/8 (0.125) and go much much lower; for example, I have a couple of filters at 0.067 whereas the DEQ's lowest setting is 0.1 (or 1/10).......

....so I have a feeling I'm doing something wrong or there is a scaling multiplier somewhere. Am I doing things right, or did I miss a step?

what's the correct mode in REW and in the DEQ?

I've read the DEQ2496 manual over, and I dont see a place where you can change the units on it

[brucek]

The FBQ can set bandwidths from 1/60th to 10 octaves.

The DEQ can set bandwidths from 1/10th to 10 octaves.

The FBQ setting in REW will go from (1/60th octave = 0.017) up to (10 octaves = 10)

So a FBQ filter of 0.067 = 4/60th of an octave = 1/15th octave.

The DEQ doesn't allow that size of a bandwidth, so you would have to use the smallest 1/10th = 0.10

brucek

[ssabripo]

gotcha! that's what I figured....thanks Brucek!

[wlmirage]

Hi Bruce,

I am planning to do the room evaluation to find out where in the room to apply acoustic treatment in addition of the sub-woofer placement. Is the DEQ any better than the FBQ or DSP? Sine it costs a lot more and I believe it has a better sound quality if using it as an equaliser.

Will

[brucek]

The DSP is theoretically not available anymore and is replaced by the FBQ and superior specs. The only disadvantage with the FBQ over the DSP that I can see is that it only allows a single program of filters, while the DSP allows many. Not really a showstopper.

The DEQ is a different machine completely. Low frequencies respond well to equalization, while higher frequencies are better suited to be dealt with by treatments, traps etc.

I see no reason to move from the FBQ up to the DEQ for a subwoofer unless you want some specific feature. Their specs are the same..

brucek

[terry j]

I would like to add a little here, not to contradict anyone but maybe a slight difference in perspective on the use of the DEQ at higher frequencies.

Personally I would without hesitation cough up the extra few bikkies for the deq.In addition to being able to fix up the bass, you can also use it to correct the frequency response of the speakers themselves. Well, to be a little more precise, you can set the FR curve to whatever your own personal tastes are!!

Where I totally agree with Bruce on the correcting the higher frequencies issue is if you applied any sort of eq in that area based upon measuring from the listening position. Then you are not correcting the speaker, you are compensating and attempting to correct for the room and are, quite frankly, on a hiding to nothing.

However, either outdoors if you can else in a place of minimal room reflections, measure the speaker from say 1m then eq the SPEAKER (ie definately NOT the room) flat, I only do the auto eq from around 100 hz or so, as anything below that falls into the normal procedure of the shack and is corrected in the bass at the listening position. It will be now closer to 'perfect' in the 'plus or minus Xdb' measurement, which we want.

The now corrected speakers are put in the normal position, then the everyday shack procedure of correcting the bass follows as normal, we simply ignore any corrections above the normal bass frequencies. Why?? Because, as Bruce rightly points out, any corrections in the mid or high frequencies are best corrected by room treatment.

I will point out that if you do use the deq, then to use the auto eq feature then you will need the ecm 8000 as well, which is an extra expense to consider. Unfortunately, having the ecm won't mean you don't need the RS meter, because to get the signals into the computer with the ecm to use REW, you will need a mixer which will be an additional expense again.

I personally feel that these small extra expenses are worth it though.

[wlmirage]

I am new to this DEQ, FBQ. Yes, I would like to first get the treatment for my audio room first before setting up the sub. What is the process to to apply the treatment using this DEQ or FBQ? I also heard the DEQ can not work with the REW.

[brucek]

I also heard the DEQ can not work with the REW

The midi interface doesn't work with a DEQ yet. You need to manually enter the filters. No big deal. takes about two seconds...

What is the process to to apply the treatment using this DEQ or FBQ?

These are parametric equalizers made by Behringer (along with the more common BFD) that are used between the sub out of your receiver/processor and subwoofer amplifier. Use REW to get a response of the room with the subwoofer and use the filters it recommends in the parametric equalizer to smooth the response of the sub. That's the short story.

See the Room EQ wizard and BFD Guide ICONS at the top of this page for the long story.

brucek