Chicagoland Theater and Music GTG: Rockin' the burbs!

Matthew J Poes

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Hi Everyone,

I wanted to do a quick write-up on a get-together I attended and participated in. I think its important to document these here on AV NIRVANA while this forum grows under the hopes that as we have more people from around the country, we can start to have more of these GTG's amongst local folks. Many of these GTG's have grown to a point where audio dealers, manufacturers, and company reps are now attending. This GTG had more than 30 attendees from all over the place. We not only had local people from the Chicago area, but people from Texas, Michigan, and even Canada.

I love the idea of a GTG because its provides a space to experience gear we wouldn't normally get to experience, to be amongst like minded individuals, to geek out to what we like to geek out to most, and to listen to great music or watch great movie clips together. It's also a great place to provide teaching/learning amongst members.

I hope this is ok, but for now, here is a link to the forum where we know each other and planned this event. It is quite long, so don't feel compelled to read it all. I plan to post information from this event to help people catch what they can.

AVS Forum post
http://www.avsforum.com/forum/155-d...eaker-sub-gtg-meet-plainfield-il-chicago.html

My friend Mike over on AVS "Eng-399" graciously hosted this event and I will be asking him to come over here and share if possible.

Here is a link to a video on the Audio Thesis Demo room. We had the proprietor of Audio Thesis in Texas come up and setup a demo with some awesome gear he imports from Italy.
https://www.audiothesis.com/
-MasterSound Tube amplifiers
-North Star Design Dac/CD Player
-Ross Fiorentino Fiesole
-Dayens Menuetto
-Aurilac source gear and Dac

There was a lot of current and future speakers from the DIY Soundgroup guys, including one of the primary designers of those kits, Matt Grant.

I did a short seminar on using REW to evaluate a room's acoustic quality and interpreting the data in a useful way. The room in question was a good room acoustically, which made it difficult to show bad results. Additionally, we ran out of time to do a pre and post treatment, but I hope to do a dedicated video at a later date doing just that. I'll post links to this video as soon as I can.

The video may be pretty funny to watch. Sonically I'm a purist. I like big bass and realistic volume as much as the next guy, but when it comes to tonal balance, especially for movies, my preferred response curve varies only about 6-7 db's from completely flat. Mike like's his bass and had it setup with a significant shelf filter that lead tot he bass being 50db's hot from the mains. While the rise in bass was very smooth and even, it was extreme. Where as my incline may be akin to grating land for drainage, his was akin to Mt. Everest. This was a problem because low frequencies are steady state and largely minimum phase. While the RT60, clarity, and decay above 100hz would be right, below that point you would see extreme ringing. The graphs would simply be too hard to interpret and the scale would make it difficult to see what are normally big variations. As a result you will see a lot of exacerbation from me in trying to measure and interpret this live.

Another great teaching moment came in trying to setup an AB comparison between two speakers with different tonal balance and thus response curves. Setting the levels with an SPL meter lead to one speaker sounding distinctly louder than the other. While one could listen through the loudness difference, and argue that the other is more tonally balanced, the "louder" speaker caught your attention. By using an RTA measurement instead, we were able to do two things. First we could be sure that the speakers were level matched better, given the response differences. Second, the owner oft he brighter speaker remembered that he had a treble resistor lift switch engaged that allowed the CD to operate "unrestricted." while that speaker was never as flat at the other, by engaging the resistor we were able to get a much more even response out of that speaker and the response between the two became less distinguishable. For many, it became a more informative comparison. the lesson for everyone is that unless the speakers are identical and your using something like a 1khz test tone, that an RTA may be a more appropriate way to level match speakers.

More pictures and videos coming!
 

Matthew J Poes

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Joined
Oct 18, 2017
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Here are the videos from the REW Acoustics Class I did. Remember this was meant to be a short high level talk. It doesn't show a pre post, but just a how to interpret the data. It was done in takes because the camera kept running out of memory and because we had, um, issues with the bass level.

Take 1

Take 2

Take 3
 

tripplej

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Joined
Jul 13, 2017
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6,867
More  
Preamp, Processor or Receiver
NAD T-777
Universal / Blu-ray / CD Player
Oppo 103 Blu Ray Player
Front Speakers
7 Paradigm Reference series 8" in ceiling speakers
Subwoofers
2 Paradigm SE Subs
Other Speakers or Equipment
Nintendo Wii U Gaming Console
Video Display Device
Samsung UN75F8000 LED TV
Remote Control
Universal Remote MX-450
Streaming Subscriptions
Sony PS4 Gaming Console, Panamax MR-5100 Surge
Very nice. Thanks for sharing. :)
 

Eng-399

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Joined
Dec 3, 2017
Messages
4
Thanks Matt for sharing my GTG and thanks again for teaching the guys about REW! I hope this helped a few guys that where there. I really wish I had more time so I could a taught a class on how to use WINISD and input drivers into the program... maybe next time. Here's a few videos of the day and my room. I'll post pic's of the day in another post but the day a lot fun and everyone who stopped by had something to bring to the meet of all aspects of audio video.






https://youtu.be/teYw_K5_yTQ
 

tripplej

AV Addict
Joined
Jul 13, 2017
Messages
6,867
More  
Preamp, Processor or Receiver
NAD T-777
Universal / Blu-ray / CD Player
Oppo 103 Blu Ray Player
Front Speakers
7 Paradigm Reference series 8" in ceiling speakers
Subwoofers
2 Paradigm SE Subs
Other Speakers or Equipment
Nintendo Wii U Gaming Console
Video Display Device
Samsung UN75F8000 LED TV
Remote Control
Universal Remote MX-450
Streaming Subscriptions
Sony PS4 Gaming Console, Panamax MR-5100 Surge
Very nice. Thanks for sharing.
 

Matthew J Poes

AV Addict
Thread Starter
Joined
Oct 18, 2017
Messages
1,903
Thanks Matt for sharing my GTG and thanks again for teaching the guys about REW! I hope this helped a few guys that where there. I really wish I had more time so I could a taught a class on how to use WINISD and input drivers into the program... maybe next time. Here's a few videos of the day and my room. I'll post pic's of the day in another post but the day a lot fun and everyone who stopped by had something to bring to the meet of all aspects of audio video.






https://youtu.be/teYw_K5_yTQ
Thanks for stopping in Mike, I hope you contribute more. Your endless DIY sub projects would be a great inspiration around here.
 
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