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Post by Thunderduck on Jan 7, 2015 9:11:53 GMT -5
Thank you very much Tony!!
Yes, Definitive has helped me before. I will definitely get in touch with them. |
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Post by foggy1956 on Jan 7, 2015 11:30:29 GMT -5
Tony,
Thank you for all your help. I will pick up a couple acoustic panels and try to figure out where to hang them.
Paul
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Post by ansat on Jan 7, 2015 11:47:36 GMT -5
Tony, Thank you for all your help. I will pick up a couple acoustic panels and try to figure out where to hang them. Paul For proof of concept, you can use heave comforters or carpet padding. (Both will not have big effects on lower frequencies, but they are usually easier to work with and cheap to test with. |
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KeithL
Administrator 
Posts: 10,255
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Post by KeithL on Jan 7, 2015 14:19:45 GMT -5
Just a thought, but you can have cancellations and standing waves at any frequency..... your center is 12" from the floor, which is right about 1 wavelength at 1 kHz. You might see what happens if you put a nice heavy mat or carpet on the floor directly under the center, and extending several feet forward - at least temporarily. Lonnie/Ansat, Thanks for the response. The sub is a PSA XV15se. Based upon Lonnies response, it looks like I have loose floorboard that the it's sitting on. Could this be the reason? Ansat: the centre is sitting on a homemade stand, 12" high. I guess this could be resonating. I will move the sub and place the centre on the floor to rule out the stand. Thanks for the responses. Just put a towel under the center to decouple it. |
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Post by Thunderduck on Jan 13, 2015 0:15:30 GMT -5
Good Evening,
Trying to teach this old dog new tricks. I am posting my latest Dirac run and would like a quick primer on reading the below graphs. The first graph shows the before and after when I ran Dirac following the manual instructions very closely and it covered 3 seating positions. The second graph is a session were I concentrated every measurement around my main listening position.
My main question concerns the hills and valleys. What do they mean? Which hill or valley would I use to set my crossover for these speakers?
If you like, I can provide the other graphs. If/when I do in the future, is it better to provide the combined graph or is it better to do the before and after separately?
Ok, here goes with the graphs.
 
Thank you very much for taking a look and putting up with my questions.
Regards,
Steve
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Post by ansat on Jan 13, 2015 8:44:44 GMT -5
Hey Steve,
I would say 50hz, even though you have extension to 30hz. And that assessment would be the same on both graphs. You can see that the speaker is struggling below that mark. As for the difference in the peaks and gains, the more spread out the measurements, usually the flatter the sum. Low end room response can vary wildly in a room. The 2nd graph is a more accurate visual of your main listening position. If you were to just take a measurement at the mlp then proceed. (Don't load the filter) you would see exactly the response at the mlp only.
Tony
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Post by Thunderduck on Jan 13, 2015 17:55:28 GMT -5
Hi Tony,
Sorry for the delayed response. Really appreciate the feedback.
If I may ask a clarifying question, when reading the graph for setting a crossover, is it basically the first big DIP that you look for? Oh how I love my technical talk. Also, do you go by the before reading or after?
Thank you for putting up with all these newbie questions. The XMC is the first really audiophile receiver or amplifier that I have ever owned. All previous units did not have all these settings that could be changed other than setting a crossover freq. Any room correction was basically moving a mic around and that was it. Nothing like the settings that can be changed in the XMC or even the UMC-200.
Getting off my soapbox now.
Best Regards,
Steve
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Post by ansat on Jan 13, 2015 21:35:20 GMT -5
Hey Steve, I look at the before graphs and how much frequency that the dip covers. At 30 to 60hz your ears hear changes in 5 to 10 hz increments. Basically 1/3 to 1/6 octave and an octave being a double of frequency. (10 to 20 is one octave and 20 to 40 is a octave and so on) since your dropoff is a full half octave, your ears will hear that easily.
Tony
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Post by Thunderduck on Jan 13, 2015 21:38:20 GMT -5
Thanks Tony, got it!
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Post by rswood on Jan 17, 2015 15:13:11 GMT -5
I hope someone can answer this question. When measuring my speaker levels with radio shack digital sound meter, and after running Dirac my two sub connected as mono read about 5 to 6do lower than the other speakers.
AGC is turned off and mic levels set to max before running Dirac. Subwoofers were level matched to the mains and to each other using sound meter.
My question is it normal to see a 5 or 6db differential from the mains using this meter or am I doing something wrong?
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Post by ansat on Jan 17, 2015 15:23:59 GMT -5
I hope someone can answer this question. When measuring my speaker levels with radio shack digital sound meter, and after running Dirac my two sub connected as mono read about 5 to 6do lower than the other speakers. AGC is turned off and mic levels set to max before running Dirac. Subwoofers were level matched to the mains and to each other using sound meter. My question is it normal to see a 5 or 6db differential from the mains using this meter or am I doing something wrong? Is this accurate? no. Is it normal? in my experience and troubleshooting, yes, unfortunately it is. The current work around is adjusting the levels in the dirac settings. Tony |
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tubby
Emo VIPs 
Route 2 in Weekapaug!!!
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Post by tubby on Jan 17, 2015 16:34:10 GMT -5
I have always found the rat shack meter to read low on measuring sub frequencies. It may not mean dirac set them low.
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Post by Jim on Jan 17, 2015 16:37:57 GMT -5
I have always found the rat shack meter to read low on measuring sub frequencies. It may not mean dirac set them low. There are correction tables for the different RS meters that can help if you're doing test tones - or using REW. Not terribly helpful for level setting with low passed pink noise. But yeah. They can be off 5-10 db for some frequencies. |
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Post by ansat on Jan 17, 2015 16:56:07 GMT -5
I have always found the rat shack meter to read low on measuring sub frequencies. It may not mean dirac set them low. There are correction tables for the different RS meters that can help if you're doing test tones - or using REW. Not terribly helpful for level setting with low passed pink noise. But yeah. They can be off 5-10 db for some frequencies. I think for the most part there is a misunderstanding of the meter. See the curve below and notice the rolloff.  However, my comments are more geared to a discrepancy of what I am seeing between the emotiva cal and mine as well as others. Tony |
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Post by Jim on Jan 17, 2015 19:46:52 GMT -5
There are correction tables for the different RS meters that can help if you're doing test tones - or using REW. Not terribly helpful for level setting with low passed pink noise. But yeah. They can be off 5-10 db for some frequencies. I think for the most part there is a misunderstanding of the meter. See the curve below and notice the rolloff. However, my comments are more geared to a discrepancy of what I am seeing between the emotiva cal and mine as well as others. Tony I understand that you're talking about the rolloff associated with the curve - but some of the frequencies measure pretty far off. You do make a good point however - so as to not ignore the curves. www.avsforum.com/forum/113-subwoofers-bass-transducers/505236-spl-meter-correction-tables.htmlI'm a little fuzzy on the Dirac issue/behavior with subs. Is it Dirac software behavior that results in the lower than expected spl or the Emotiva mic being inaccurate? |
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Post by ansat on Jan 17, 2015 20:10:15 GMT -5
I think for the most part there is a misunderstanding of the meter. See the curve below and notice the rolloff. However, my comments are more geared to a discrepancy of what I am seeing between the emotiva cal and mine as well as others. Tony I understand that you're talking about the rolloff associated with the curve - but some of the frequencies measure pretty far off. You do make a good point however - so as to not ignore the curves. www.avsforum.com/forum/113-subwoofers-bass-transducers/505236-spl-meter-correction-tables.htmlI'm a little fuzzy on the Dirac issue/behavior with subs. Is it Dirac software behavior that results in the lower than expected spl or the Emotiva mic being inaccurate? I believe that the emotiva calibration is 6db too hot. Still working on proving it. Tony |
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Post by rswood on Jan 18, 2015 17:12:52 GMT -5
I believe that the emotiva calibration is 6db too hot. Still working on proving it. Tony Just so I understand what you are saying, XMC is misreporting to Dirac 6db to hot and Dirac is compensating by lowering the sub level by 6db. The work around is to just raise the sub level in Dirac to taste? Thanks for your help. |
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Post by ansat on Jan 18, 2015 17:17:13 GMT -5
I believe that the emotiva calibration is 6db too hot. Still working on proving it. Tony Just so I understand what you are saying, XMC is misreporting to Dirac 6db to hot and Dirac is compensating by lowering the sub level by 6db. The work around is to just raise the sub level in Dirac to taste? Thanks for your help. This is what I suspect and have confirmed with my microphone. I have gathered enough data comparing measurements between calibrated microphones and the emotiva microphone to state that there are some microphones that the emotiva cal file is causing dirac to increase the highs and lower the lows. And yes, currently that is the work around. I am working on a better solution, but I am not ready to post it yet. Tony |
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Post by rswood on Jan 18, 2015 20:43:39 GMT -5
Just so I understand what you are saying, XMC is misreporting to Dirac 6db to hot and Dirac is compensating by lowering the sub level by 6db. The work around is to just raise the sub level in Dirac to taste? Thanks for your help. This is what I suspect and have confirmed with my microphone. I have gathered enough data comparing measurements between calibrated microphones and the emotiva microphone to state that there are some microphones that the emotiva cal file is causing dirac to increase the highs and lower the lows. And yes, currently that is the work around. I am working on a better solution, but I am not ready to post it yet. Tony Your work is greatly appreciated, Thanks! |
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hemster
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Particle Manufacturer
...still listening... still watching
Posts: 51,950
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Post by hemster on Jan 20, 2015 17:51:00 GMT -5
I reran Dirac a couple more times today. I suspect there's a serious room issue at around 170-180 Hz. Any comments/analyses are welcome. The first 5 charts are spectrum graphs and the last 4 are impulse. I didn't see any point in attaching an impulse graph for the sub. Note: I use only 1 sub in this configuration. |
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