Thought I would share this in the subwoofer forum but dont want to
start a war between BFD and Audyssey as they both may have pros and cons.
I tried AVRs with Audyssey (Denon 688 and Onkyo 705) and just
didnt like the result with Audyssey. I also didnt have any control over
it other than changing the speaker distance and level. Where as with BFD
I could key in the gain at any frequency and see how it affects.
Anyway... like I said I dont want this to be a debate on whether
Audyssey is superior.
So decided to go back to BFD. My first BFD unit from partsexpress was defective.
I got a new one from Zzsounds and this one worked.

After several tweaks I got it to within about 5db.
The curve may still not be considered flat. I doubt if my
ears or inexpensive gear would be able to tell the difference
even if I am able to bring it within 3db.

I will post all the details tomorrow. This is only with the mains. I still have to do the sub. But I only have to do it from 50Hz below as I am sending the filtered full range from the BFD to the receiver and then let the receiver do
the cross over. So since the full range is filtered it works just fine even now with the sub. My sub has a peak of some 88db at 36 and 45Hz. I only have added 6 filters so far. So I need to add 2 more to take care of those peaks of the sub.

BTW this is all for 2ch music only. I am not a movie guy.

Anyway... will post some details tomorow.

Thought I would share this in the subwoofer forum but dont want to
start a war between BFD and Audyssey as they both may have pros and cons. I tried AVRs with Audyssey (Denon 688 and Onkyo 705) and just
didnt like the result with Audyssey. So decided to go back to BFD. My first BFD unit from partsexpress was defective. I got a new one from Zzsounds and this one worked.

After several tweaks I got it to within about 5db.
The curve may still not be considered flat. I doubt if my
ears or inexpensive gear would be able to tell the difference
even if I am able to bring it within 3db.

I will post all the details tomorrow. This is only with the mains. I still have to do the sub. But I only have to do it from 50Hz below as I am sending the filtered full range from the BFD to the receiver and then let the receiver do
the cross over. So since the full range is filtered it works just fine even now with the sub. My sub has a peak of some 88db at 36 and 45Hz. I only have added 6 filters so far. So I need to add 2 more to take care of those peaks of the sub.

BTW this is all for 2ch music only. I am not a movie guy.

Anyway... will post details tomorow and would appreciate some feedback.

Well first your graph is wrong, octaves should be spaced evenly,20-40 should be spaced the same as 40-80 should be spaced the same as 80-160 etc.. Doing so will give you a better representation on how it all sounds. 1/3 octave tones are not enough. That is why Audyssey uses a log rhythmic sweep :eek: or is it linear, and finally take your measurements from at least 4-6 spots in the room, with at least a Behringer ECM8000 mic cause two feet away from that spot you may be worse off then you think you are. I hope those measurements aren't from a radio shack SPL mic??? :confused:

Well first your graph is wrong, octaves should be spaced evenly,20-40 should be spaced the same as 40-80 should be spaced the same as 80-160 etc.. Doing so will give you a better representation on how it all sounds. 1/3 octave tones are not enough. That is why Audyssey uses a log rhythmic sweep :eek: or is it linear, and finally take your measurements from at least 4-6 spots in the room, with at least a Behringer ECM8000 mic cause two feet away from that spot you may be worse off then you think you are. I hope those measurements aren't from a radio shack SPL mic??? :confused:

Yeah I read in the BFD guide about using better mic but I didnt want to spend some $500-1000 just for the mic and a lot of people use Radioshack SPL. Keep in mind that I am a beginner.

I will make the frequency scale as log scale. I didnt use 1/3 oactave tones. I downloaded the test tones from 25 to 208 Hz with 1hz increments up to some 120Hz and then it is 125, 142.5, 160,167,208. The following are the frequencies I used as I skipped some in between, just too many of them.
25,28,31.5,33,36,38,40,42,45,47,50,53,56,60,63,67,71,74,77,8 0,83,87,89,92,96,100,104,108,111,115,120,125,142.5,160,167,2 08

I also added the corrections to the Radioshack SPL. Note that the corrections are high only in the very low frequencies. Once you hit the 50's the correction is only like 1 or 2 dbs. For what I am doing I guess 1 or 2 dbs wont make a big audible difference.

For the time being I am taking measurements only at the listening position as this is mainly for 2ch audio and I am the only listener in the room. I am not trying to replicate how Audyssey works. So lets not try to compare one on one with Audyssey. My main goal here is to kill the nasty peaks and get rid of the boomy bass and from what I hear I guess I am able to achieve this.
Besides I have 36 measurements to make and I had to make them so many times to tweak the curve. So first I want to get this done at the listening position and see what I get and then I can start acting like a pro :-)

I have the plot in log scale. I could not get Excel to show only 40 to 210Hz (in log scale) . So I had to
use a different software which could not smooth out the curves.

Well you gotta start somewhere and it looks like you have made improvements to the FR. So good job!

The next step is to download Room EQ Wizard (free software) and hook your mic up to your pc. A little more setup and there's a learning curve for REW, but it makes taking measurements a lot easier.

Well you gotta start somewhere and it looks like you have made improvements to the FR. So good job!

The next step is to download Room EQ Wizard (free software) and hook your mic up to your pc. A little more setup and there's a learning curve for REW, but it makes taking measurements a lot easier.

Agreed, REW and a BFD make a great combination. The thing I believe you are forgetting is is you are only addressing your FR from 20Hz to about 200Hz while Audyssey addresses your full FR.

I am using my BFD with REW to address 20Hz to about 100Hz and letting Audyssey from my Denon receiver handle everything else. Of course Audyssey is still affecting 20Hz to 100Hz, but I am then flattening it out after that.

I tried Audyssey. May be I didnt do it right. My Denon 688 was probably defective because when I used the Audyssey the sound use to fluctuate i.e increase and decrease. With 705 it messed up the mids and highs and the bass was still boomy. Again may be I didnt do it right. I have already returned both.

My main concern is the boomy bass. I like a bright sound. May be I could tone down the mids a bit so that they are laid back but I may not keep my Klipsch RB81. I am planning to get the Vienna Acoustics Mozart (though over my budget) or the Dynaudio Audience 72.

I did some more tweaking with some slight changes to the listening/measuring pisition and I guess I have got good results except for a suck out. I am ok with small suck outs compared to nasty peaks.

BTW I did try the REW but I had the hum issue from my PC. I tried some isolators from Radioshack but they didnt work. So I could not proceed with it and decided to do it manually. Moreover I dont have a lap top and it was just too much trouble to pull the entire pc set up to the living room and try it. I didnt work anyway due to the hum. I should probably borrow a lap top and then try it, now that I have a good start.

I am using my BFD with REW to address 20Hz to about 100Hz and letting Audyssey from my Denon receiver handle everything else. Of course Audyssey is still affecting 20Hz to 100Hz, but I am then flattening it out after that.

So, you applied changes via the BFD after you ran Audyssey?

So, you applied changes via the BFD after you ran Audyssey?

Yes, I have tried to set my receiver with no EQ (audyssey off), use REW and my BFD, then run Audyssey and found that I either get the same results or worse.

So now I run Audyssey first, I choose the 'FRONT' EQ setting on my Denon (I like this EQ setting over Audyssey) then filter 20Hz to 100Hz with my BFD and REW.

It is weird, if I filter first, then run Audyssey, I seem to get worse results.

Below, please find my FR, I don't have one from BEFORE I run Audyssey, this shows the after effect.

http://i53.photobucket.com/albums/g69/logan12586/Basement/5-2-2008turbo.jpg

General BFD question: Can the rack mounting brackets be removed without any negative effects to the unit? They look like they can, but I figured I'd ask first. :cool:

General BFD question: Can the rack mounting brackets be removed without any negative effects to the unit? They look like they can, but I figured I'd ask first. :cool:

Yes but they'll be a hole there showing the internals, nothing is behind them.

I wasnt getting much low bass before so I bumped up the low bass portion. I like this one better. I might cut down the low bass by another 3db or so and see how that sounds.

BTW is there a way to copy an entire filter to another so that if I want to make minor changes I dont have to redo everything. I want to make one with minor tweaks and do A-B comparison. I didnt see a way to copy a filter to another in the BFD manual. Anyone?

I wasnt getting much low bass before so I bumped up the low bass portion. I like this one better. I might cut down the low bass by another 3db or so and see how that sounds.

BTW is there a way to copy an entire filter to another so that if I want to make minor changes I dont have to redo everything. I want to make one with minor tweaks and do A-B comparison. I didnt see a way to copy a filter to another in the BFD manual. Anyone?

Nice house curve, are you filtering up to 200Hz?

Also, I believe there is a way to copy one filter to another, but I don't have the manual with me. I think you may have missed it if you say that you can't find it in the manual.

http://i30.photobucket.com/albums/c349/TimRP/response.jpg

Which one is more correct, which one is measured with the proper mic, which one do I trust?

One was recorded with a MXL 604 condenser with omni capsule. One was recorded with a MXL V67 large diameter diaphragm condenser.

Both into the same mic pre amp. 60Hz peak is a hum that I had from going from my recording PC that is upstairs to my receiver downstairs. Audyssey is in action but only with the Audyssey mic in the same position on three passes.

Both into the same mic pre amp. 60Hz peak is a hum that I had from going from my recording PC that is upstairs to my receiver downstairs.

If you're using REW, you should be able to filter out the hum. Have it record/sample/whatever the hum with no other sounds, then it can remove it from your real tests.

I had great success using the PEQ (http://www.pvconsultants.com/audio/eq/peq.htm) spreadsheet to simulate the BFD before making changes to the filters. I created my own test tone CD that matches the frequencies of the spreadsheet and used my Shack SPL meter for measurement. I was within about 2db of the simulated response after everything was tweaked.

-Robert

Do all AVR's that come with Audyssey use a $500-1000 mic? I dont think so.
As long as I like what I am hearing thats all matters to me :-)

Nice house curve, are you filtering up to 200Hz?

Also, I believe there is a way to copy one filter to another, but I don't have the manual with me. I think you may have missed it if you say that you can't find it in the manual.

I am sending full range signal from OPPO 980 to the BFD. The BFD is
connected to my receiver which then does the bass management.
The test tones I got from hometheatershack only go up to 208Hz.
I guess any peaks over 200hz may not cause boomy bass so
I didnt bother to find test tones over 200Hz and see if there are
any peaks.

I have an old Yamaha receiver RX-V795a that has a fixed cross over at 80hz or 90Hz (I remember reading in the manual that it is 90Hz) and also my sub (Sunfire True sub jr) cant go over 100Hz. So I decided to send full range to the BFD. I am hearing subtle distortion in the highs occasionally. First there is a D/A on OPPO and then there is A/D, D/A on BFD and my receiver also does A/D to apply bass management. OPPO 980 is known to do a good job with
D-A. My yamaha receiver also does a good job. I dont expect the $99 BFD to have great converters. So I could expect some distortion, especially when it is done so many times. Ultimately I am planning to get the SVS SB-12 and a new AVR and send only upto 200Hz to the BFD via the AVR cross over. This way I dont have to send full range to BFD and always worry about sound degradation.

I had great success using the PEQ (http://www.pvconsultants.com/audio/eq/peq.htm) spreadsheet to simulate the BFD before making changes to the filters. I created my own test tone CD that matches the frequencies of the spreadsheet and used my Shack SPL meter for measurement. I was within about 2db of the simulated response after everything was tweaked.

-Robert


so does the PEQ perform the simulation and show me the corrected curve or just outputs the data and then I have to use another software to do the simulation. Looks like a neat tool but I am sure if that includes the simulation module also. I am not sure how the simulation works. It is beyond my league anyway. As long as there is a free software that does it, fine with me :-)

well I downloaded the PEQ excel spredsheet. But I am not sure how to get the FRD data. Is that something I can create from my measurements. But I dont know the phase. I only have the frequency and the magnitude (SPL reading). Could I just put a same value for phase for all measurements?

I downloaded the PEQ, made the frd file of my measurements and imported that frd file into PEQ. But it doesnt show the full curve. It only shows up to some 100Hz though the date is there. Also it doesnt show the frequency in the x-axis nor the db in the y-axis.
Any idea? I ave attached the picture. As you can see the curve got cut. My original curve in in my post above.

I didnt have much luck with the PEQ spreadsheet but I found out that the REW can do the same thing and even better. All this time I have been making measurements everytime I added a set of filters and also trying to decide where to put the filter. I used the REW and this is what I got. I wanted to keep the bass a bit higher but I could not get a flat curve elsewhere. I guess given the fact that I have only 12 filters that is the best I could do. I used up all 12 filters. Now it is time to do some serious listening :-)

oops didnt add the picture. Here it is.

I didnt have much luck with the PEQ spreadsheet but I found out that the REW can do the same thing and even better. All this time I have been making measurements everytime I added a set of filters and also trying to decide where to put the filter. I used the REW and this is what I got. I wanted to keep the bass a bit higher but I could not get a flat curve elsewhere. I guess given the fact that I have only 12 filters that is the best I could do. I used up all 12 filters. Now it is time to do some serious listening :-)

Nice curve, is your FR your sub only or is it sub and 1 speaker?

Nice, Mupi. It makes a big difference, doesn't it? Congrats.

Good to hear some encouraging replies.

The FR is sub and front speakers together. Fronts set to small
and my old yamaha receiver has one fixed cross over at 90Hz

I used the FBQ2496 as the equalizer in the option in REW and using 16 bands I can get better curve. I have ordered the FBQ2496. Only problem with the FBQ is that it only has 1 filter where as DSP1124P has 12. But folks have said that FBQ has better circuitry than DSP so I would prefer the FBQ as I may not have much distortion even if I send full range.

I have not listened to the curve I got from the DSP1124p. It should certainly be better than what I manually made before.

I will listen to it later this week and compare the SPL measurements to what REW gave. Tonight is for CNN only (primaries) :-)

I am sure if I use all 20bands on the FBQ it can get even better.

One concern I have is that I had to add gains at 3 or 4 places and I had to add up to 5.5db. I hope that is ok and wont pull in too much power.

well I entered the filters that I created from REW back into BFD and then took
the measurements using SPL. Look what I got!. No I didnt not manipulate any numbers. I was really surprised to see that kind of correlation between the REW simulation and actual SPL measurements. Then how would the REW simulated curve using FBQ2496 measure? Super flat? I cant wait to get the FBQ2496.

There is a suck out at 71Hz. I had entered some gain at the location but if that is a null in my room I guess there is not much I can do about it as no amount of EQ boost will change a null right? I dont mind 1 suck out as I dont have any boomyness. Now
I can go back and forth between the source to which I have hooked up BFD and the source to which I have hooked up OPPO via optical cable. I guess all that boomyness is gone and I still have the deep bass as I have taken care of that region in the curve.

May be I dont need the SVS-SB12 and a new receiver. If the FBQ2496 has better circuitry and if there isnt even that subtle distortion in the highs that I see with the
DSP1124P, I guess I could live with sending full range to the FBQ2496.

Anyway... if I change my mind and get the SVS-SB12 I will post my results.

Now I will do some measurements at a couple of more locations near my listening location and see if there are any major nulls/peaks. Right now my listening position is right at the back wall. My couch is right againts the back wall.
I guess nulls dont occus at the ends of the room. Right?

Now can I get the same results with Audyssey? I dont want to buy onkyo 705 or Denon 688 again. Even if Denon has other options like Front EQ or something, low end Denons are useless to me as they dont have pre-outs. I have to get the $1199 2808CI to get the pre-outs, ridiculous. How come Yamaha has not yet added audyssey to their AVR's.

Anyway.. I will throw in some of the CD's I use to hate as they sounded boomy and see how they sound now.

The last thing you want to do is add any gain, you can/will do some serious damage to your sub as it is straining play the frequencies you applied gain. As you said, you may be in a null at those frequencies so adding gain will be even worse.

Proceed with caution, but you have been warned ;)

Got an 1124P collecting dust since I installed my acoustic treatments :)

http://img138.imageshack.us/my.php?image=graph1mo2.jpg

Got an 1124P collecting dust since I installed my acoustic treatments :)

http://img138.imageshack.us/my.php?image=graph1mo2.jpg

so what kind of treatments have you added to your room. Could you please put a picture of those.

I could try to read that master acoustic treatment thread but it has over 100 pages and all I need to know is what material to use and where.

After doing some reading it looks like I need to take care of the first/early reflections on the side walls and also add corner bass traps. I have some idea what to get for the bass traps but I am not sure about treating the reflections. I dont want to put the wrong material or put too much and make it dead. Do I put absorption panels of diffusion panel.
Any hint would be appreciated.

well the boomy bass is gone but after some A-B listening with and without BFD, I notice significant distortion of the highs. I am sending full range to BFD and I attribute this distortion to poor/cheap circuitry. Someone in the other thread posted a sarcastic remark saying that how much can a couple of converters distort the signal. Well get yourself a BFD, send a full range signal and hear for yourself. I hear it myself and thats all matters to me.

I am going to try the FBQ2496 as people say it has better circuitry. It is $149 vs $99 for DSP1124. Will see how much improvement in sound 50 bucks can bring. Also this time I will only send the bass and not full range.

I am also going to try the OC 703 panels based on the suggestions by many and that fact that bass traps reduce the peaks and remove/improve the nulls. I am also going to use the OC 703 as absorbers on the side walls.

Why not just send the bass through your Behringer now - if thats what you plan to do with your new one?