Measurement Help

[Ciscokid]

Hi, again i would like to thank everyone for all your help getting me up and running. I think this program is great. I have been testing and moving my speakers around to try and improve my results.( speaker placement makes a huge difference. Even moving as little as a few inches)I am currently testing the Left/Right and both my Subs at the same time.I have ran test on each individually, but I feel that testing all speakers at once gives me a true idea of my problem areas. Is this correct?

I would like to know how I can add my center channel into my testing along with the other speakers I have mentioned?

I have an Outlaw 990 Processor. Currently I am using a USB soundblaster live 24 external card. I Use a Stereo cable Y spliter to split the line out to my Video 5 inputs left and right channel.

Here are my latest results.they are both the same just one is waterfall out to 600ms. I am now looking into getting a BFD as well as some acoustical treatment.

[brucek]

but I feel that testing all speakers at once gives me a true idea of my problem areas. Is this correct?

Not really. If there's a peak at 80Hz for example, is it caused by a room resonance or a crossover interaction between the sub and main? You can't know unless you test and equalize individually. Then you can play them together to observe any interaction around the crossovers...

brucek

[DrWho]

For starters, your subwoofer looks to be about 10dB too hot - it will sound weird at first when you turn it down, so give it some time before you decide it sounds better turned up. (annoying psychoacoustics). You will probably end up somewhere around 6dB down from where you're at now, but try it knocked down 10 first and then turn it up a few dB later.

That said, it looks like you have a fundamental issue in the 35Hz region, and then a lot of modes in the 50-70Hz region. It would be easier to see if you set your waterfall to logarithmic instead of linear Bass traps tend to be effective above 50Hz and then it's also going to clean up your octave around 150Hz too (provided it's implemented correctly).

Seeing the individual responses with the crossover of the receiver is always beneficial too...I wonder if you couldn't rotate the phase of your sub a bit to knock out the 80Hz peak and then bring up the response in the 60Hz region. Polarity inversion would be too much, but something more like 90 degrees.

Btw, are these plots smoothed at all? Unsmoothed would be the most informative at the lower frequencies.

[Ciscokid]

DrWho;21075]For starters, your subwoofer looks to be about 10dB too hot - it will sound weird at first when you turn it down, so give it some time before you decide it sounds better turned up. (annoying psychoacoustics). You will probably end up somewhere around 6dB down from where you're at now, but try it knocked down 10 first and then turn it up a few dB later.

First of all thank you for the reply.I ran somemore tests. I set the sub 10dB lower as you specified. It brought it down to where it should be. I will listen for a few days as you stated and see how it sounds.
Also I ran tests for just left and right speakers by themselves.I will post them for you to see.

That said, it looks like you have a fundamental issue in the 35Hz region, and then a lot of modes in the 50-70Hz region. It would be easier to see if you set your waterfall to logarithmic instead of linear Bass traps tend to be effective above 50Hz and then it's also going to clean up your octave around 150Hz too (provided it's implemented correctly).

I posted the Logarithmic graph. As far as the bass traps go I intend to put to bass traps in my front corners of my room.I am curious if this is going to be enough to help.I plan on them being floor to ceiling 4 inch thick 705.I would like to put more treatment but with the wife I am lucky she is letting me do that.
I also was thinking of getting a BFD to help also.From what I have read this will not help my voids on the graph correct? It will just help the tame the peaks, from what I understand. Please correct me if I am wrong.

Seeing the individual responses with the crossover of the receiver is always beneficial too...I wonder if you couldn't rotate the phase of your sub a bit to knock out the 80Hz peak and then bring up the response in the 60Hz region. Polarity inversion would be too much, but something more like 90 degrees.

I messed with the phase a bit and ran test. I am using 2 subs. First I tried shutting one sub off and played with the phase.Then I ran both subs same phase.Finally I tried both subs oposite phase.I got the best response with running them opposite.(one 0 and one 180). On this setting I was able to correct some of the problems at the 35hz region as well as the 50hz to 70hz region.

Btw, are these plots smoothed at all? Unsmoothed would be the most informative at the lower frequencies

No they are just the raw data.No smoothing.


Here are the graphs.The first is just the left front speaker on its own. Second is Right front speaker.Third is Left-Right with both subs.Last is waterfall.Thanks again for all you insight.

[Ciscokid]

Whoop's forgot graphs.

Here are the graphs.The first is just the left front speaker on its own. Second is Right front speaker.Third is Left-Right with both subs.Last is waterfall of third..

[terry j]

hey ciscokid

re the log vs lin graphing, if you can see lin in the window then it is the log graph showing, and likewise if you can see log in the window then it is the lin graph!! Clear as mud???

Try clicking on it and see the change.

kind regards

terry

[DrWho]

You know the graph is showing linear when the distance between frequencies is the same everywhere. So the distance between 20 and 40Hz should be the same as 200 and 220Hz.

You know it's log if the distance between octaves is the same. So the distance between 20 and 40Hz should be the same as 200 to 400Hz.

I just put my fingers on the screen to measure an octave down low and then compare if it matches the octaves up high. If not, then I hit the button.

[Ciscokid]

Sorry I totally screwed up when saving the graphs and didn't pay attention.Here they are. First and second is left/Right and Subs.Then left channel by itself and right channel by itself.

[Wayne A. Pflughaupt]

Okay, now we can address some of your questions.

Ciscokid wrote:

I posted the Logarithmic graph. As far as the bass traps go I intend to put to bass traps in my front corners of my room. I am curious if this is going to be enough to help.

The traps (if done right, and if there are enough of them) reduce the long low frequency decay times via absorption. They won’t necessarily smooth response, or reduce decay times for the entire low frequency range, but they do help with nulls, I believe.

I also was thinking of getting a BFD to help also.
From what I have read this will not help my voids on the graph correct? It will just help the tame the peaks, from what I understand. Please correct me if I am wrong.

The BFD can help with both. The only thing it can’t address is nulls (don’t mistake every low-point in response as a null).

I messed with the phase a bit and ran test. I am using 2 subs. First I tried shutting one sub off and played with the phase.Then I ran both subs same phase.Finally I tried both subs oposite phase.I got the best response with running them opposite.(one 0 and one 180). On this setting I was able to correct some of the problems at the 35hz region as well as the 50hz to 70hz region.

What’s the story on your subs? Ideally, they should be matching and co-located. Depending on the room, separate location is doable, but it is much more difficult to get optimal results

Regards,
Wayne