First Graph...opinions??

**mrrjw** · **10-22-07, 07:24 PM**

Does this look good, bad, or what? Mine is the blue line...the other is something else.

**brucek** · **10-23-07, 12:34 AM**

Are you saying yours is the magenta colored line? If so, it's good....

brucek

**mrrjw** · **10-23-07, 09:27 AM**

Quote:

brucek wrote:

Are you saying yours is the magenta colored line? If so, it's good....

brucek

No, mine is the blue line. The magenta is not supposed to be there.

**brucek** · **10-23-07, 11:13 AM**

Quote:

No, mine is the blue line. The magenta is not supposed to be there

You have a +10dB peak at 40Hz that needs to be removed. (along with the magenta line

)

**mrrjw** · **10-23-07, 10:21 PM**

Quote:

brucek wrote:

You have a +10dB peak at 40Hz that needs to be removed. (along with the magenta line

)

I hear ya...I had a basketball game and was running late. Sorry for the pink line.

I was also thinking (please let me know if I'm wrong here) that I could boost the signal from the 53Hz to the 80Hz. It looks like if I the cutoff wasnt 80Hz on my receiver than right about 80 (or maybe higher) there would be a low point. Then I would raise the levels on my fronts to get a smoother transition from the sub to the mains. Please let me know if this is sounding like a good idea. It seems like it

.

Also these measurements were taken 2 days ago. Today I used my SPL meter to manually adjust my speaker levels (MCAAC or whatever before). I also then reran the "auto EQ" with mic on my receiver today after setting the levels. It looks like my receiver has a "BFD" internal...just not for the sub

oh well

Maybe this last question should be for another post, but I'll ask it here since it looks like you da man!!! Should I do some sort of FR graph using test tones that are going to my mains, centers, and rears to manually set my EQ in my receiver or should I just let the MCAAC auto EQ it? It does sound freaking great after I did manual adjusting for the levels and then the auto EQ using "front align". But then again, I thought it sounded good before the manual too. So, is this something people do or is the auto thing the way to go?

Thanks for your help!!

**brucek** · **10-24-07, 05:54 AM**

Quote:

I was also thinking (please let me know if I'm wrong here) that I could boost the signal from the 53Hz to the 80Hz

I wouldn't worry about that area until I added the mains to the sub and did a measure to see how the overall response works out. The peak at 40Hz is a bigger concern.
Have you considered using REW to take your measurements? It's more accurate and much easier.

Quote:

Should I do some sort of FR graph using test tones that are going to my mains, centers, and rears to manually set my EQ in my receiver or should I just let the MCAAC auto EQ it?

I would use the Auto EQ system first and then do your testing of the sub and the sub + mains after it's complete.

brucek

**mrrjw** · **10-24-07, 09:05 AM**

Quote:

brucek wrote:

I wouldn't worry about that area until I added the mains to the sub and did a measure to see how the overall response works out. The peak at 40Hz is a bigger concern.
Have you considered using REW to take your measurements? It's more accurate and much easier.

I would use the Auto EQ system first and then do your testing of the sub and the sub + mains after it's complete.

brucek

That initial test was run with the sub and the mains. The receivers xover is set at 80Hz. So when the signals I used were above 80, the main were producing them. I will redo the tests tonight since I recalibrated everything last night, and post the results here.

I have definately considered REW. I downloaded it and read through all of the help files. My only problem is that I do not have a good enough sound card and would have to purchase an external one to make it work. Someone very helpful, who has a BFD, told me he did all of his measurements and graphed it using excel. So, since I didnt have a proper soundcard, I did it this way.

As for the auto EQ thing. I still dont understand. I will redo my sub measurements with the mains on, with the test tones I used previously, tonight. But my question is still: Should I recalibrate the "auto EQ" afterwards? I would have to send test tones from 80Hz up to 4kHz (or something like that) as my EQ on my receiver allows me to control gains on certain freqs ( like 250Hx, 1kHZ, etc). It also has something called "trim" control. I will redo the graph and post tonight with the new results.

Thanks,
Russell

**brucek** · **10-24-07, 12:08 PM**

Quote:

My only problem is that I do not have a good enough sound card and would have to purchase an external one to make it work

Actually the cheap cards make out the best since there are less 'features' to get in the way. The soundcard calibration you do initially with REW effectively removes the poor response of any card - as long as it has a line-in and a line-out.

Quote:

But my question is still: Should I recalibrate the "auto EQ" afterwards?

Use the Auto EQ first with all speakers connected and let it do its thing. Then use REW to take a measure of the sub and do your BFD EQ. Then add the mains and tweak the BFD as necessary around the crossover. Then don't touch the Auto EQ after that unless you want to go through the whole routine again....

brucek

**mrrjw** · **10-24-07, 04:31 PM**

Quote:

brucek wrote:

Actually the cheap cards make out the best since there are less 'features' to get in the way. The soundcard calibration you do initially with REW effectively removes the poor response of any card - as long as it has a line-in and a line-out.

Use the Auto EQ first with all speakers connected and let it do its thing. Then use REW to take a measure of the sub and do your BFD EQ. Then add the mains and tweak the BFD as necessary around the crossover. Then don't touch the Auto EQ after that unless you want to go through the whole routine again....

brucek

In the help files for REW: Note that microphone inputs are NOT suitable and should not be used.

My soundcard has an input (that looks like a microphone input) and an output.

Also, I just noticed that the cprrection or compensation factors I used were for the older model meter. I will have to use the ones for the digital RS model, as thats the one I have..oops.

I will be at it tonight again and post my NEW results.

**brucek** · **10-24-07, 05:36 PM**

Quote:

My soundcard has an input (that looks like a microphone input) and an output.

Not suitable if it's a mic input...........

brucek

**mrrjw** · **10-24-07, 10:00 PM**

Okay..I finished listening to all that noise finally. Please tell me which on of these setting you think looks better. Here are my results:

This graph is with the xo set at 50Hz on my receiver. The blue line is the auto EQ set to "all channel adjust" and the magenta line is "front align".

This is xo at 80Hz, "front align":

This is xo at 80Hz, "all channel adjust":

Well there it is. Now I know I need a BFD for that peak at 40Hz. And maybe that lull from 56-80...give it a little boost.

My opinion is this..please let me know yours:

I think the bottom graph looks the best. Since the 50xo point drops so bad from 50-63Hz. These are played by by mains at this point and I cant boost them anyway right now. The bottom and middle are similar. However, the middle graph has a higher peak in the mains at 111. but like I said. The 2 are pretty similar...what do you think?

**mrrjw** · **10-24-07, 10:26 PM**

Here one more I ran real quick cause I'm obsessed

!!! This is at x/o point 100Hz.

**brucek** · **10-25-07, 09:04 AM**

You must be tired of listening to tones by now... whew... you better get that REW runnig....

Anyway, the crossover ar 80Hz is likely the best. The dip at 80Hz crossover is usually cleared up by adjusting the phase control on the sub(s), or the distance control for the sub in the receiver. Once you start using a 100Hz crossover for a sub, the sub itself becomes localizable. Best to keep it at 80Hz if possible.

The 80Hz plot looks pretty good though, except for the 40Hz peak. You need a BFD. Try fixing the crossover dip a bit with the phase. Play tones in the 80Hz area with the sub and mains on and play with the phase control(s) and or distance.

brucek

**mrrjw** · **10-25-07, 09:56 AM**

Quote:

brucek wrote:

You must be tired of listening to tones by now... whew... you better get that REW runnig....

Anyway, the crossover ar 80Hz is likely the best. The dip at 80Hz crossover is usually cleared up by adjusting the phase control on the sub(s), or the distance control for the sub in the receiver. Once you start using a 100Hz crossover for a sub, the sub itself becomes localizable. Best to keep it at 80Hz if possible.

The 80Hz plot looks pretty good though, except for the 40Hz peak. You need a BFD. Try fixing the crossover dip a bit with the phase. Play tones in the 80Hz area with the sub and mains on and play with the phase control(s) and or distance.

brucek

Okay cool...thanks for all the quick responses!! and thanks for the homework. I will mess around with the phase and distance tonight (maybe..since my girl is coming home I might not have too much time

).

Another thing I was playing with last night was the large/small setting for the speakers. I think I like it small...what your thoughts on that?

I was also wondering why my graph from after 80 Hz has those two spikes. Esp at 111Hz on both graphs. But I guess theres nothing much I can do with that right?

I've made up my mind..I'm getting a BFD

and I am trying to locate a cheap usb soundcard to use REW when I get it..any suggestions?

**mrrjw** · **10-26-07, 01:57 PM**

Okay, after several attempts to make this better...this I the best I could do. My plan is to purchase a BFD and take care of the spike at 40Hz. Hopefully, it does this for me without problems. I tried my best to get rid of the spike at 100Hz. However, when I removed it by adjusting the speaker distances or phase, it would just appear somewhere else. I thought I was clever by getting it to peak at 125Hz, since my Pioneer receiver has a dB adjustment on its EQ at that freq. BUT...when I raised the lull that was at 125Hz, it raised all the other freq the same amount. In other words it just shfted my graph up by what I increased the 125Hz by. Anyway, I was thinking, maybe just maybe the BFD could help with this. Even though my x/o is set at 80Hz, it seems as if playing with the subs phase or distance still affected the 100Hz signal. SO..I would conclude that some of this signal is being played by the sub, even though the cutoff point is set at 80 (guessing its not a straight drop off point but more or less attenuates down to 0dB eventually). And by that assumption, maybe the BFD connected to my sub could help out there too

!!

Here are a few more questions for the VERY helpful bruce all mighty

1. any recommmedations on a cheap USB soundcard and where to get it?

2. I did all my cals at first in my "movie mode". So, all of the 80-160Hz signals were sent to my center channel. Thats how I did the initial graph. The one in this post I set to "stereo" so only my mains were on? I was going to redo the center graph (while set to "movie" mode) to try to match its graph with my mains. Good idea? or am I a crazy insane perfectionist?

3. cant think of 3 ...THANKS FOR THE HELP!!!

**brucek** · **10-26-07, 02:20 PM**

Quote:

Even though my x/o is set at 80Hz, it seems as if playing with the subs phase or distance still affected the 100Hz signal. SO..I would conclude that some of this signal is being played by the sub, even though the cutoff point is set at 80 (guessing its not a straight drop off point but more or less attenuates down to 0dB eventually). And by that assumption, maybe the BFD connected to my sub could help out there too

Well, yes and no. By 100Hz, the sub signal is down in level quite a bit and would have minimal effect in the mix of the sub + mains. Look at this graph showing both the subwoofer response and the mains response overlayed together when you are using a 80Hz crossover and the resultant mixed flat signal in red (in a perfect world)... the sub is down a fair bit at 100Hz......

80crossover sub plus main.jpg

Quote:

any recommmedations on a cheap USB soundcard and where to get it?

Seems a lot of members use the Creative SoundBlaster Live 24 bit external, but any external card is fine if it has a line-in and a line-out.

Quote:

I did all my cals at first in my "movie mode".

Not a good idea. All subwoofer testing should be done with the receiver in simple stereo mode and all effects and tone controls and effects off. I know you have the auto eq and that's fine..... but then do your measuring in stereo mode. Normally you test with the sub only and the mains disconnected to do your eq'ing. Then you add the mains when that is complete to check the crossover area.

brucek

**mrrjw** · **10-26-07, 02:43 PM**

Quote:

brucek wrote:

Well, yes and no. By 100Hz, the sub signal is down in level quite a bit and would have minimal effect in the mix of the sub + mains. Look at this graph showing both the subwoofer response and the mains response overlayed together when you are using a 80Hz crossover and the resultant mixed flat signal in red (in a perfect world)... the sub is down a fair bit at 100Hz......

Attachment 4703

Seems a lot of members use the Creative SoundBlaster Live 24 bit external, but any external card is fine if it has a line-in and a line-out.

Not a good idea. All subwoofer testing should be done with the receiver in simple stereo mode and all effects and tone controls and effects off. I know you have the auto eq and that's fine..... but then do your measuring in stereo mode. Normally you test with the sub only and the mains disconnected to do your eq'ing. Then you add the mains when that is complete to check the crossover area.

brucek

Okay cool. All good news. I have no more adjusting to do

As for the 100Hz spike, I guess I'll wait and see if the BFD can do it. If not, oh well. Close enough right?

I think I might buy an external sound card just to play with REW and because now that I am becoming an "expert" on this, I might try to stick a free ad out there locally to see if I can make a few extra $$. I bought the Avia2 disk recently so I would use that for audio and video adjustments also. I'm sure there are real experts out there using expensive equipment...but then again..I'll be cheap. I might even have to contact Behringer to see if I could get a discount or something if I sold a few...since thats what I would be recommending to use on everyone's system.

Speaking of $$, I was just curious how you make yours...is this your site? Did you design the REW software or the BFD? Just curious

**brucek** · **10-26-07, 02:59 PM**

Quote:

Speaking of $$, I was just curious how you make yours...is this your site? Did you design the REW software or the BFD? Just curious

Nope, John Mulcahy wrote REW. He and Sonnie are the owners of the site.
My field is electronic engineering. Been doing it for over 33 years........I simply help on the site because I'm an audio geek.

brucek

**mrrjw** · **10-26-07, 03:50 PM**

Quote:

brucek wrote:

Nope, John Mulcahy wrote REW. He and Sonnie are the owners of the site.
My field is electronic engineering. Been doing it for over 33 years........I simply help on the site because I'm an audio geek.

brucek

Okay cool! I'm a PE in electrical (7+years exp). I do boring stuff, mostly power and some instrumentation. Thats why I'm pretty clueless on the whole FR stuff.

And I too am starting to become an audio geek. This site should pay you. I've never been to a forum with such quick responses. You should also get a check from Behringer...considering I would have never heard of them if it wasnt for this site. I'm guessing the site prob does though.

Thanks for all your help.

**clubfoot** · **10-26-07, 04:20 PM**

Quote:

mrrjw wrote:

Okay cool! I'm a PE in electrical (7+years exp). I do boring stuff, mostly power and some instrumentation. Thats why I'm pretty clueless on the whole FR stuff.

And I too am starting to become an audio geek. This site should pay you. I've never been to a forum with such quick responses. You should also get a check from Behringer...considering I would have never heard of them if it wasnt for this site. I'm guessing the site prob does though.

Thanks for all your help.

Brucek is our resident quick responder and is always very helpful. I couldn't agree more on your Berhringer comment too.

I'll add my .02 on some of your questions.
Speakers set to small,...for sure.
Have you tried moving around your sub or seating to clear up the 40Hz bump?
As Brucek suggested, just stereo, do most of your tuning on the sub alone first, and then add the mains.

**mrrjw** · **10-26-07, 04:31 PM**

Quote:

clubfoot wrote:

Brucek is our resident quick responder and is always very helpful. I couldn't agree more on your Berhringer comment too.

I'll add my .02 on some of your questions.
Speakers set to small,...for sure.
Have you tried moving around your sub or seating to clear up the 40Hz bump?
As Brucek suggested, just stereo, do most of your tuning on the sub alone first, and then add the mains.

I like small too.

I have not tried that. Maybe I will move her around a little when I have time and run some more tests...good idea. I dont have a lot of room to play with. But I'll just get some one to read the SPL while I play the 40Hz signal and see if comes down. My luck it will, but another peak will arise..but worth a try.

I never do a test with just the sub. All my reads were with both involved.

**mrrjw** · **10-26-07, 04:37 PM**

Oh well...I played the 40, moved the sub around and it never went under 90dB.

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