Announcement

Collapse
No announcement yet.

Atlanta DIY Sat., 11/7/09

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Atlanta DIY Sat., 11/7/09

    Dave has invited us back to EarthShaking Music for an informal meeting/show and tell. A number of people expressed interest in various aspects of measurement, so, we want to make measurement an area of focus.

    we can listen to current projects in the works.

    Discuss room acoustics and measurement software and setup.

    Speaker design

    The store is open from 10am till 8pm as usual. 4-5 hours is a full day for me, say 10-3 with a break for lunch; but Dave has nothing else planned that day.

    I would like for one or two people to prepare demonstrations of EQ measurement software packages and /or speaker design software.

    We have a main sound stage area of 30x30 and two other listening rooms of about 15x30 and 15x25, as well as a testing area in the warehouse.

    Dave has a recording studio that records CD's for local artist. He can give us a demonstration of this process and the wide leeway the sound engineer has in creating the final recording product. He felt that many of the comments about sound quality at our last meet were really related to the recording process.

    So, put this on your calender and prepare for a fun session.

    Bob Howell

  • #2
    Re: Atlanta DIY Sat., 11/7/09

    Thoughts?

    Comment


    • #3
      Re: Atlanta DIY Sat., 11/7/09

      since I work on all Saturdays, totally wishing these were on Sundays...


      ...not that i'd contribute much. I'd be a spectator at best. ;p

      Comment


      • #4
        Re: Atlanta DIY Sat., 11/7/09

        Sounds great, Bob. As of now, this works for me although 11am is better than 10am given my drive and timezone.

        If it works out, I'll bring my test equipment -- a ClioWin measurement system, SPL calibrated microphone, a constant voltage impedance test jig, a small impedance measurement tool (for measuring speaker or inductor DCR to the sub-0.01 ohm range), a testing stand and manual turntable (for off-axis measurements), and my "lab amp" (the weak link in my tool-set). With these, we can measure everything from driver TS parameters to true simultaneous SPL/phase & impedance/phase. I'm pretty confident about the accuracy of these tools but would much like to compare my measurements to others' measurements to understand differences. We'll need a better test room than the last time, though, if we want measurements into the sub-100Hz range....

        I use LEAP for enclosure and crossover design. I can bring the software to demonstrate or even prepare a presentation but don't know what the audience might be interested in or what level of acoustics/electronics knowledge might be of interest. I can present on topics such as "baffle diffraction (and my opinion about why this is a dumb design goal) vs baffle step (and why this matters -- sometimes) and why they are not the same thing (to disambiguate the confusion created by those who nonsensically talk of 'baffle step diffraction')", measurement techniques and tools, or other more esoteric topics. Obviously, we'd need to pick one or two topics given the short timeframe. Anyway, let me know if this is of interest.

        robert

        Comment


        • #5
          Re: Atlanta DIY Sat., 11/7/09

          Originally posted by Robert Dunn View Post
          Sounds great, Bob. As of now, this works for me although 11am is better than 10am given my drive and timezone.

          If it works out, I'll bring my test equipment -- a ClioWin measurement system, SPL calibrated microphone, a constant voltage impedance test jig, a small impedance measurement tool (for measuring speaker or inductor DCR to the sub-0.01 ohm range), a testing stand and manual turntable (for off-axis measurements), and my "lab amp" (the weak link in my tool-set). With these, we can measure everything from driver TS parameters to true simultaneous SPL/phase & impedance/phase. I'm pretty confident about the accuracy of these tools but would much like to compare my measurements to others' measurements to understand differences. We'll need a better test room than the last time, though, if we want measurements into the sub-100Hz range....

          I use LEAP for enclosure and crossover design. I can bring the software to demonstrate or even prepare a presentation but don't know what the audience might be interested in or what level of acoustics/electronics knowledge might be of interest. I can present on topics such as "baffle diffraction (and my opinion about why this is a dumb design goal) vs baffle step (and why this matters -- sometimes) and why they are not the same thing (to disambiguate the confusion created by those who nonsensically talk of 'baffle step diffraction')", measurement techniques and tools, or other more esoteric topics. Obviously, we'd need to pick one or two topics given the short timeframe. Anyway, let me know if this is of interest.

          robert
          Information on Baffle Step and Baffle Diffraction would be interesting...if I get to come.

          Comment


          • #6
            Re: Atlanta DIY Sat., 11/7/09

            Originally posted by Robert Dunn View Post
            Sounds great, Bob. As of now, this works for me although 11am is better than 10am given my drive and timezone.

            If it works out, I'll bring my test equipment -- a ClioWin measurement system, SPL calibrated microphone, a constant voltage impedance test jig, a small impedance measurement tool (for measuring speaker or inductor DCR to the sub-0.01 ohm range), a testing stand and manual turntable (for off-axis measurements), and my "lab amp" (the weak link in my tool-set). With these, we can measure everything from driver TS parameters to true simultaneous SPL/phase & impedance/phase. I'm pretty confident about the accuracy of these tools but would much like to compare my measurements to others' measurements to understand differences. We'll need a better test room than the last time, though, if we want measurements into the sub-100Hz range....

            I use LEAP for enclosure and crossover design. I can bring the software to demonstrate or even prepare a presentation but don't know what the audience might be interested in or what level of acoustics/electronics knowledge might be of interest. I can present on topics such as "baffle diffraction (and my opinion about why this is a dumb design goal) vs baffle step (and why this matters -- sometimes) and why they are not the same thing (to disambiguate the confusion created by those who nonsensically talk of 'baffle step diffraction')", measurement techniques and tools, or other more esoteric topics. Obviously, we'd need to pick one or two topics given the short timeframe. Anyway, let me know if this is of interest.

            robert
            I would expect the first hour or so will be more show and tell. You could present you topic after lunch, if you prefer.

            Sounds interesting.

            Comment


            • #7
              Re: Atlanta DIY Sat., 11/7/09

              Hi Bob,

              Somehow I missed hearing about the SE DIY in Aug :-( ....I've not been perusing the boards much recently....However I'd like to be in for the Nov Atl DIY event. I can bring my Zaph L18/27TDFCs and heavy 24" stands. Anything else you need?

              Bob Drake

              Comment


              • #8
                Re: Atlanta DIY Sat., 11/7/09

                Hi Guys,
                I'm excited to see interest in this event.
                I'm happy to discuss anything that may be needed or desired to make this happen and useful. I can be reached by email or by phoning the store- 404-577-0707.

                Also, it never occurred to me to do this on a Sunday, but I'm here 7 days a week anyway, so it doesn't matter to me. Bob- can you take a poll of who would really like to do it Sunday? Let me know if this is even an option for you.

                Dave
                Be careful there, that thing's got 750 mW on tap!

                Comment


                • #9
                  Re: Atlanta DIY Sat., 11/7/09

                  Originally posted by bobdrake View Post
                  Hi Bob,

                  Somehow I missed hearing about the SE DIY in Aug :-( ....I've not been perusing the boards much recently....However I'd like to be in for the Nov Atl DIY event. I can bring my Zaph L18/27TDFCs and heavy 24" stands. Anything else you need?

                  Bob Drake
                  We are forming up the plans right here, so, stay tuned. You may see something else to contribute. Do bring the Zaph L18's.

                  Comment


                  • #10
                    Re: Atlanta DIY Sat., 11/7/09

                    Originally posted by bobhowell View Post
                    I would expect the first hour or so will be more show and tell. You could present you topic after lunch, if you prefer.

                    Sounds interesting.
                    Obviously, I'd like to know the level of interest so, hey everyone, chime in if you're interested. Or feel free to suggest other topics.

                    [For example, we could argue the merits of Sine vs MLS measurements. We could debate the best way to measure low frequencies in a small environment and/or how to combine rear-port measurements with front-facing driver measurements. We could debate the importance of phase alignment of drivers/cross-overs or driver size/response vs cross-over points. We could go to the design basics and discuss driver selection, Theil-Small parameters, sealed vs ported boxes (or for AJ, the advantages of dipoles which would interest me greatly since I clearly don't get it), cross-over points/goals, design goals and trade-offs. Lots of possibilities.]

                    One thing, though, Bob. You mention the testing area in the warehouse in the original post. I don't want to be overly negative, but if that is where we will have to do measurements, I'm not going to bother. It's too much work to bring/setup my equipment if it's going to be that poor a measurement environment. (Granted, I'm a perfectionist and turn off my AC and "shush!" my cats when they meow during measurements.... But you can't measure below, maybe, 300-500Hz accurately in that environment.)

                    If we can dedicate one of the listening rooms to measurements, that might be workable -- certainly better than the warehouse. The big 30x30 room would not be my first choice since good measurements require silence; people passing through would be a problem as would the bleed-out from the listening rooms. For that matter, even one of the listening rooms would require that the other not be in use during measurements.

                    So I guess it's a question of what you and the group want to do....

                    [ Why is it that I always seem to be writing a book whenever I post? Is this an affliction? Is it treatable? Are there self-help groups? <g> ]

                    Comment


                    • #11
                      Re: Atlanta DIY Sat., 11/7/09

                      HI Robert,
                      I agree that a poll of attendees to determine interest is in order.
                      WRT to the space- can you tell me how big a space you want?
                      We used the warehouse space last time- it is quiet and large and non-echoey.
                      We have other spaces available that are smaller, so let me know what is ideal for you.
                      Thanks,
                      dave
                      Be careful there, that thing's got 750 mW on tap!

                      Comment


                      • #12
                        Re: Atlanta DIY Sat., 11/7/09

                        Originally posted by vividaudio View Post
                        Hi Guys,
                        I'm excited to see interest in this event.
                        I'm happy to discuss anything that may be needed or desired to make this happen and useful. I can be reached by email or by phoning the store- 404-577-0707.

                        Also, it never occurred to me to do this on a Sunday, but I'm here 7 days a week anyway, so it doesn't matter to me. Bob- can you take a poll of who would really like to do it Sunday? Let me know if this is even an option for you.

                        Dave
                        Between Church and family, Sunday is booked for me.

                        Comment


                        • #13
                          Re: Atlanta DIY Sat., 11/7/09

                          Bob, thanks for organizing this. The date and time are fine with me and I plan to be there.

                          Robert, if you bring your measurement gear, I would be very interested. That is my next planned purchase and it would be great to hear some of your experiences.

                          -Bob B. (not Bob Howell )
                          -Bob

                          The PEDS 2.1 mini system
                          My A7 Project - another small desktop speaker
                          The B3 Hybrid Dipole - thread incomplete and outdated

                          Comment


                          • #14
                            Re: Atlanta DIY Sat., 11/7/09

                            I'm watching this with interest...just too early to make a commitment...measurement is one of the skills I need to add to the toolkit.

                            I would enjoy the L18's...;)

                            I prefer Saturday.
                            Mongo only pawn in game of life
                            ____
                            Ed

                            Comment


                            • #15
                              Re: Atlanta DIY Sat., 11/7/09

                              Originally posted by vividaudio View Post
                              HI Robert,
                              WRT to the space- can you tell me how big a space you want?
                              We used the warehouse space last time- it is quiet and large and non-echoey.
                              We have other spaces available that are smaller, so let me know what is ideal for you.
                              Thanks,
                              dave
                              Hi, Dave. Let's make sure that I'm not confusing the "warehouse" with some other space. The area where Rob Chen was nice enough to set up measuring equipment at the recent DIY event was what I assume that you're calling the warehouse. If so, that space is not, IMHO, useful at all. Maybe there was more room in the back that I did not see.

                              Theoretically, to reach a reasonably accurate 20Hz measurement, we should have a room at least 60 feet wide and a ceiling of 30 feet (i.e., microphone 30' minimum from every reflecting surface). However, we can do multiple measurements in smaller rooms -- my home "best case" is 9' ceiling and about 20'x20' -- and try to estimate the actual low frequency system response.

                              So, I'd suggest either a pretty large, very quiet room (bigger than my home's best case) or a room with as much damping material as possible. One of the listening rooms would be ok although it's not going to be absolutely accurate. But I'd certainly be happy with that. (In case it is not clear, I am something of a perfectionist -- which is kind of dumb since the hobby is engineering which is fraught with trade-offs.)

                              One other alternative: There's a pretty large parking lot behind the building. Assuming that the road noise is not too bad, that might be workable. Downside: Somebody must watch the equipment at all times lest it walk off. Oh, also need a long power cord.

                              Anyway, Dave, we don't have to have a perfect environment, just a better one than the last event. Let me know what options are available.

                              Thanks,
                              robert

                              Comment

                              Working...
                              X