# Dsp1124 For Full Audio Eq-ing



## vince (Oct 19, 2007)

Hello,
I am new to using this unit and am just getting used to all the funtions of it. I do have the gear to take very accurate room measurments. My question is, I hear everyone talk about this unit for sub equalization but not for full range eq purposes. Is there a particular reason for this? noise or perhaps impeadance matching problems for higher freaquencies???
Thanks,
Vince


----------



## warnerwh (Nov 28, 2006)

The DEQ 2496 is much more versatile for full bandwidth equalizing and has the BFD built in. That' my .02.

Many people don't believe in using equalization. With the DEQ 2496 doing it in the digital domain I can't imagine what people are worried about. I've got quite a high end music system in a custom treated room and could not hear any degradation for this piece.


----------



## terry j (Jul 31, 2006)

ditto on the deq. check it out

http://www.enjoythemusic.com/magazine/equipment/0705/behringerultracurve2496.htm


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

> Many people don't believe in using equalization.


I have a theory that most of those are people who have never tried it, or who did and didn’t know what they where doing and made a mess of things.



> With the DEQ 2496 doing it in the digital domain I can't imagine what people are worried about.


Personally I don’t like the prospect of an extra AD/DA conversion in the signal chain. That’s why I stay with analog for the time being. Nice to know that the conversion is minimal to non-existent, at least...

Here’s a guy who recently tried some analog EQs in his system and was very happy with the results.

http://www.hometheatershack.com/forums/rew-forum/6691-my-first-rew-please-chime.html

Regards,
Wayne


----------



## imbeaujp (Oct 20, 2007)

Hello, I am in the buying process of a FeedBack Destroyer for Sub EQ. Could it makes more sens to buy the DSP 1124 ? and EQ sub + Full range ?

Thanks !

JP


----------



## warnerwh (Nov 28, 2006)

"I have a theory that most of those are people who have never tried it, or who did and didn’t know what they where doing and made a mess of things."

I'm sure you're right. It amazes me too how the people who say they don't like equalizers have no facts to defend themselves.


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

imbeaujp said:


> Hello, I am in the buying process of a FeedBack Destroyer for Sub EQ. Could it makes more sens to buy the DSP 1124 ? and EQ sub + Full range ?


Actually, you don’t want the 1124 for full range, you want the DEQ 2496. In order to use the same EQ for both mains and subs, you have to have a system that will allow you to insert it _in front_ of the crossover. Otherwise you need an EQ for each seperately.

Regards,
Wayne


----------



## imbeaujp (Oct 20, 2007)

Thank you !

JP


----------



## vince (Oct 19, 2007)

Thanks guys, I am now just using for sub, took many readings to get good average at listening position. response is much improved! needs more tweaking though.. Had to use cheater adapter plug to eliminate hum, might burn house down but bass sounds nice:bigsmile:
Vince


----------



## Doug Plumb (Mar 16, 2007)

Personally I can take or leave sub EQing, but midband EQing when done right is very beneficial - especially when listening to dialogue. It doesn't have much of an affect on music but a smoothed out (correctly) midrange makes all the difference.

When you are watching movies and hearing dialog a few dB of midband correction even in one spot makes a huge difference.

I use the BFD in my signal path with my speakers - PSB M2's - difficult to improve on but I have 2dB of sharp cut around 3 KHz to absolutely flatten the midband of these absolutely excellent speakers.

You can't do it with horns - only point source. You can't define a response for horns so easily.


----------



## jpmst3 (Feb 11, 2007)

Hey guys,

I have no idea how to use any of the Behringer products. I am currently using an SMS-1 and it works well for sub duty. 

However, I am adding a second sub and I have no way of adjusting phase independently on each sub.

Is this something that could be done with the DEQ? Also, is there some sort of auto-eq that can be done using the DEQ and ECM8000? 

Sorry for the dumb questions but I really have no idea how any of these product work and what the capabilites/limitations are...


----------



## huff (Oct 15, 2006)

Doug Plumb said:


> Personally I can take or leave sub EQing


I had never equalised my sub (had it in my HT for 2 years) until I came here and learned REW and then bought a BFD 2 weeks ago. I have to say now that it has made an enormous difference, especially at increased playback levels. I will never leave a sub unEQd again!

REW showed me I had 2 significant 6-8db humps - 32Hz and 43Hz - that absolutely made the bass sound boomy at higher levels. With the EQing in place, it now sounds like real bass and not just a boombox. I always thought the sub just wasn't very good (it's an Energy ES-10 10in. sealed - OK but nothing special), but now it impresses me with what it can do after being EQd. Of course, that still won't stop me from buying a better sub at Xmas!

For $100, I can easily say the 1124P has given me more value for the $$$ than any other part of my system.


----------



## Doug Plumb (Mar 16, 2007)

My rrom doesn't really require sub EQing - there is a resonance at 140 Hz, but still I think the EQing at around 3 KHz is more significant. But I listen to dialog much more than music.


----------



## brucek (Apr 11, 2006)

> My rrom doesn't really require sub EQing


You're one of a very few lucky people then. Most experience at least one large peak in the 20Hz-80Hz region corresponding to an axial resonance from typical home room dimensions. These peaks have the effect of overpowering the other bass frequencies resulting in one-note bass and the perceived loss of low end extension. Huff's rather well worded post above is very typical of the amazing things a little EQ can accomplish.

brucek


----------



## terry j (Jul 31, 2006)

jpmst3 said:


> Hey guys,
> 
> I have no idea how to use any of the Behringer products. I am currently using an SMS-1 and it works well for sub duty.
> 
> ...


phase (I think) is analogous to time delay, off hand I can't recall if the deq has that capability, would have to check. If all you are doing is sub eq then I would not be sure the extra expense of the deq would be worth it.

The deq can do auto eq, but in the few times I've checked it against REW it is not a super high degree of accuracy (I take the rew readings over the deq...valid??) but can certainly help. I would assume that you can/will use REW anyway so you can always tweak the auto eq results, or just go straight to rew and do it manually.

Doug, it doesn't seem to be this thread, but I recall you saying once about using eq to correct speakers, what method/procedure do you use?


----------



## Doug Plumb (Mar 16, 2007)

"Doug, it doesn't seem to be this thread, but I recall you saying once about using eq to correct speakers, what method/procedure do you use?"

I use my software. Its below in the link. See the Ch on Practical Acoustics. RPlusD emulates the BDF exactly. I'm not sure how Johns software works but mine uses a time domain emulation with identical discrete values as the BFD for freq & Q.

What my software says the BFD does to measurements is exactly what the BFD does. With RPlusD you take take 32 measurements average them (or not) and emulate the BFD through them. Setting the BFD with measuremenst is slower with RPlusD to get curve updates because of the applied emulation.

The only source of error in mine is that the anti aliase filter in the BFD is not emulated so the gently sloping response from 0 Hz to -about 0.5 dB at 20 Khz is not modeled.


----------



## terry j (Jul 31, 2006)

thanks Doug

been a while since I visited your site. Funnily enough, I was trying to work out all the computer connections and soundcard calibration (computer stuff that to a beginner like me was/is very confusing) for both your demo version and REW way back when, somehow I managed to get REW working and so by default I've stuck with it. I could probably get yours working now (simply because I've worked one out ha ha), what does interest me in yours is the ability (I think) to be able to get the relative time arrivals of impulses from different speakers, I can't get REW to do that for me, either I'm an idiot (likely) or the facility doesn't exist (yet?). I'm mucking about ATM with rear stereo channels using the L-R signal, and time delay which I just use a tape measure for to test the basic premise.

One thing I do remember from the last time I visited was some very good and interesting 'application' notes, so I will definitely take your advice above...I presume you mean chapter four 'practical measurements' in the manual??


----------



## imbeaujp (Oct 20, 2007)

Hello,

Regarding the parametric EQ fonction, How many filters is best required for sub EQ ?

FBQ2496 = 20 filters per channel
FBQ1124 = 12 filters per channel
DEQ2496 = 10 filters per channel

And, is it a way to combine the 2 stereo channels to one mono channel ? and double filters ? Can I put the output from channel A to the input of channel B without distorsion (for SUB EQ) ?

Thanks !!


----------



## Doug Plumb (Mar 16, 2007)

"One thing I do remember from the last time I visited was some very good and interesting 'application' notes, so I will definitely take your advice above...I presume you mean chapter four 'practical measurements' in the manual??"

Right.


----------



## Doug Plumb (Mar 16, 2007)

"Regarding the parametric EQ function, How many filters is best required for sub EQ ?"

Depends - usually two or three is all you need - if any.


----------



## brucek (Apr 11, 2006)

> Can I put the output from channel A to the input of channel B without distorsion (for SUB EQ) ?


Yep, but why would you want so many filters. Less is more when it comes to applying equalization. Usually four to eight filters is plenty for a sub woofer correction. Any more and you're usually using filters with unnecessarily large Q's or filters with very small cuts and gains that don't impart a significant effect.

brucek


----------



## imbeaujp (Oct 20, 2007)

I am just trying to figure out how many filters I am gonna use. So if everyone agree that 3 to 5 filters is ok for sub EQ, I will go with the FBQ1124. You are right, less filters is best. 

Thanks !


----------



## Doug Plumb (Mar 16, 2007)

Is there a link for this FBQ 1124 ? I can't find it - is this model number an error ?


----------



## imbeaujp (Oct 20, 2007)

Sorry, it's DSP1124

http://www.behringer.com/DSP1124P/index.cfm?lang=eng


----------



## vince (Oct 19, 2007)

I have to agree with doug about the number of filters. Four or five in my case would be fine. But ultimately whould depend on your room design, placement of your sub, and manufactured response of your sub. If these three things are OK then like Doug has said just a few filters are needed. I use the DSP1124p and found 12 filters is more than enough when you have this kind of control(parametric) vs. (graphic)
I used Dougs (Acoustisoft) software and reccomended hardware with laptop to take 32 measurments in an area around listening area, then averaged the readings, then started tweaking. I think the DSP 1124 and this software setup is the best thing since sliced bread!!! now my sub sounds very tight and quick, before was thick and bloated! Treating your room properly is also a huge! help. "F Alton Everest" (Master Handbook of Acoustics) awesome book for undrstanding sound. I designed my room using this books help and am very pleased. Also treated my room using this book and R+D software!
Sorry to be so long winded:whew:
Vince Dallaire


----------



## Doug Plumb (Mar 16, 2007)

The best way to set up your sub is the way I explain in ch4 of my manual posted on the site below. Get the greatest amount of energy into your listening area with experimental placement then apply the corrections as needed. This will give you a system in which the sub exerts minimal effort and excites all of your room modes.

For full range EQing its important to set your speaker up in the room center away from as many early reflections as possible, then a large number of measurements averages out any remaining reflections. For EQing you only want to correct for resonances at mid/HF's and avoid correcting for reflections.


----------



## vince (Oct 19, 2007)

So Doug, then what you are saying is one sould not EQ any room effects imparted on the speaker, but instead just EQ abnormalities that would be measured in an anohic emviroment? One sould not EQ for boundry response influences??? Seems to me any flat speaker response is ruined soon as it is put in any room! But within that room there are some placements that "are" better than others. By the way I will read chapter four of you the R+D manuel again, must have missed something:scratchhead:
Vince


----------



## Doug Plumb (Mar 16, 2007)

"So Doug, then what you are saying is one sould not EQ any room effects imparted on the speaker, but instead just EQ abnormalities that would be measured in an anohic emviroment? One sould not EQ for boundry response influences???"

Right. You can't EQ out the effect of single reflections because their effect is too dependent on mic position.

"By the way I will read chapter four of you the R+D manuel again, must have missed something"

You can ask me here.


----------



## terry j (Jul 31, 2006)

Overall I tend to agree very much with Doug on this...there was another thread quite recently on this wasn't there...???

I should run a few quick measurements to show my point, but as Doug says (and I recall Ethan had a good plot that shows this too, will hunt it up) when we get to 'full range' frequencies the placement of the mic makes a huge difference, move it one or two inches to the side, forward or back etc and you will get VERY different results.

Which one is THE one you need to be correcting for?? And in all likelihood you probably have not even by 'luck' gotten the mic in the same position as one of your ears, let alone the other.

The bass frequencies don't change anywhere near as drastically and so can benefit from eq, yet as far as I can tell Ethan is still against that too, could never quite marry that up with my own results but oh well.

Another way to look at this I suppose is assume what is the 'perfect' speaker. Let's assume that FR-wise it is totally flat, ie all frequencies produced equally with correct phase etc etc etc.

Put it in a room, 'correct' full range as an experiment, and then put it back in the anechoic chamber and retest. We would see (I'm sure) HUGE fluctuations all over the place in it's response, in other words the frequencies are no longer being reproduced accurately.

If I get time tonight I'll run a few quick sweeps and see what I can show.

By the way, the procedure I use is exactly the same as Doug, make the mains flat 'anechoically' (I do it in room but only correct down to say 100 - 150 hz ) and then I later eq the bass flat.

It may have been this thread (?) but I mentioned I couldn't get ETF running when I first tried (or mentioned it somewhere)...FINALLY got it running last night strangely enough. Pheww. Was all the stupid soundcard settings or something that mucked me up, made sure I wrote them down this time ha ha ha.

If you read this Doug (I'm still working my way through it now, your answer might point me to it more quickly than otherwise) what I need right now (in addition to whatever else I discover with it) is an ability to determine the delay or otherwise of the signals from various speakers. I'm experimenting with rear channels for example, and would like to see by how much they are delayed from the fronts. Also, I'm experimenting with placing multiple subs around the room, and for these I DON"T want delay at the LP, so I would like to measure each relative to the fronts, see what the (differing) delays are and time delay them all to be the same ie zero relative to the fronts.

Hopefully I explained that.....is your software capable of doing that task?? It is a real pity that REW is unable, or at least I have never been able to work out how to do it.

Had a quick look for Ethans article, couldn't find it. Anyway it was about how the sometimes reported changes given by cables might be explainable by sitting down in a slightly different position after getting up and performing some equipment swap, which by the mechanism outlined above could lead to slightly different FR. He posts a few shots of how the Fr varies quite a bit from only a minor mic position change, and it is the change in the higher frequencies that are of interest in this discussion.

Hopefully he (or someone else) will post the article or shots here, will save me re-doing the measurements tonight as his article is better than anything I could write anyway.


----------

