# Paging Prof: Group delay view w/ PC Adv. MCACC



## hearingspecialist (Mar 15, 2010)

Hello Prof,

How do I access the Group Delay tab with my PC viewing advanced mcacc? When I go to it it tells me: "no data". What am I not doing to get that to show information? I've spent hours trying to figure out what I'm doing wrong or not doing correctly.

Please advise,


Brian in Bakersfield...:dontknow:


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## Prof. (Oct 20, 2006)

Brian,

When I view Group Delay Characteristics on my projection screen, I go to Review Reverb Settings in MCACC which then shows the delay characteristics for the individual frequencies..
I don't see why it would be any different when viewing it on a PC..
I presume that you have done a Reverb test..


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## hearingspecialist (Mar 15, 2010)

Yes sir I always do and what's also interesting is that for the first time (of many) when I print the parameters it shows me the individual values in 5db steps freq by freq 8 slots for some value of "L". Very interesting, the numbers across top go from 0-7 with EQ freq's going downward at far left and all the timing measurements from stated 0 to stated 7. I'm thinking this "L" is probably level because below each group of numbers is "Level db=58 + Value". :dontknow:


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## Prof. (Oct 20, 2006)

That sounds different than what I see on Reverb View..
So if you're now seeing this and can print it out, is the data now showing up?


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## hearingspecialist (Mar 15, 2010)

nope, nothing on the group delay tab, just all of the amazing info when I print. Now I printed from work this time and I know it prompted me to alter the excel doc once I saved it to my desktop so maybe all the other times whatever i have at home inhibits me from all the data. It printed a boat load of pages too not like when I printed from home. I was shocked from the "stack" of paper and valuable info after i printed, one would have to pay huge amounts of money to have someone come into your home to provide all this, just crazy all the amazing abilities.

Current: all 3 set at the 40-60ms delay, all 3 standing wave measurement points used, and my most recent thing was plugging one port tube on each sub enclosure to "de-tune" and drop hopefully some freqs...on paper now 15hz tuning with 80hz x-over and levels at -3.5db with reference levels still flirting with volume setting of -16db.


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## Prof. (Oct 20, 2006)

Have you noticed any difference in overall frequencies above x-over with the 3 point calibration, as compared to centre point calibration? Has this opened or closed the sound field?
Did you completely seal the port or can air still pass through?


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## hearingspecialist (Mar 15, 2010)

Yes sir I have noticed a bunch and also better resolution for sure. The standing wave freqs are more defined and not so much a guess now or averaged. Just flat out better resolution all over the board but also opens up so many crazy ways to place mic for measuring. I have not messed with adjusting the Q values or semi tweaking the freq choices after standing wave measurements and really curious how adjusting the Q factors the quality of the sound and resolution of the filters. What has been your experience with adjusting and tweaking the Q's and filters?


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## Prof. (Oct 20, 2006)

That is something I haven't played around with either..I don't fully understand what affect Q values have..
In the early days I did play around a bit with the filter freq's. but I didn't really notice any difference by ear, so returned them to the original settings..
i guess with the right instruments and knowing what you're doing, it could possibly improve things further..

With the 3 point mic. position, I guess you could even set it up for the back row seats, if you have them..
Would be interesting to see how that would affect the sound then to the front seats..

I did some further calibrations last night..I wanted to see what effect would be achieved by just running Full Auto on Symmetry..and then Auto - All Data - THX selected..but not set any specific delay time..just letting MCACC do the setting..and not make any manual adjustments to the EQ settings..as I've done previously..

The results quite surprised me!..The first thing I noticed was that front sound felt more wrapped around me..like a curved screen affect..
Overall sound balance between voices, background sound and music was excellent..and in a crowd scene, you could hear the ambience all around you and I felt for the first time that I was in the middle of the crowd!
I don't know what delay MCACC has set, but I'm sticking with it! :bigsmile: :T


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## hearingspecialist (Mar 15, 2010)

That's awesome and when I think i've out-smarted it i run the Expert and I get reminded real quickly how much smarter it is than I. It must be higher than the 40-60ms and I am so curious how those slower times would sound. Too bad we couldn't get together with a few and really explore the setting with all the other variables controlled, just to enjoy all the adjustability.

I forgot to answer about plugging the ports, what I did was stuff 2 medium sized dish rags into each port and that seemed to work. I ran all 3 programs again to hear/see if having the x-over at 80hz and my first standing wave correction at 63hz, then 74hz, and finally 96hz what all that would do to the sound. I re-ran some blue rays that I knew had major lower freq output and even my girls said it shuddered more and was tonally deeper. Sometimes audio/sound goes against logic especially when it comes to plugging one port to drop an octave type stuff. Just like audiology...everything is backwards.


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