Announcement

Collapse
No announcement yet.

RS100-4 x2 + RS75T-8 + OT19NC00-04 Center Channel

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

  • #31
    So here is the data plugged into VituixCad. The measurements all exhibit the monster 200 Hz room mode because nothing was equalized in these initial measurements.

    Click image for larger version

Name:	Power & DI.jpg
Views:	154
Size:	530.0 KB
ID:	1490807

    I'm struggling to understand what the Directivity Index is giving me that the power response is not.
    Using 2nd order slopes for everything, I expected the dispersion to be very even and I suppose this is verifying this.
    But what information is contained in the below and worth all those dang 60 measurements that the power response in PCD won't give me?

    Click image for larger version

Name:	Power & DI alone.jpg
Views:	139
Size:	76.4 KB
ID:	1490808

    Comment


    • #32
      Verified some more things this morning:
      1. The GEQ in my HD receiver appears to be minimum phase, and with no EQ applied the chosen crossover topology still produces deep reverse nulls. If anyone chooses to build these, I would strongly encourage you to stick to the published topology but judiciously apply your own EQ for room correction as I think the impacts are significant.
      2. The impedance hump from the OT19 tweeter is not audible to me based on the current crossover. Disconnecting all the other drivers and only listening to the OT19 with both an LCR trap flattening the impedance and without one sounds exactly the same. Even listening to James Taylor, which was a great suggestion by the way. I can see how his voice would highlight the area in question. I took some measurements to see if there was something I was missing and admittedly, the HD2 is slightly higher without the LCR trap.
      Without LCR trap:
      Click image for larger version

Name:	tweeter on axis without LCR ar 12 inches.jpg
Views:	148
Size:	95.8 KB
ID:	1490831

      With LCR trap:
      Click image for larger version

Name:	tweeter on axis with LCR ar 12 inches.jpg
Views:	132
Size:	95.6 KB
ID:	1490832

      Frequency response is affected minimally:
      Click image for larger version

Name:	tweeter LCR analysis.jpg
Views:	132
Size:	114.5 KB
ID:	1490833

      However, if anyone wanted to build these and couldn't bear the agony of knowing that the tweeter impendence was undamped, the LCR trap does not affect the phase significantly and one could be dropped in with no other adverse impacts to the speakers. A 1.0 mH coil paired with a 28 uF cap and 4.0 ohm resistor nail the hump at 950 Hz.

      Now the only thing left is to figure out coil placement on the crossover board and solder things up.

      They sound very, very nice.

      Cheers,

      Comment


      • #33
        As usual, bravo,Greg!
        Wolf
        "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
        "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
        "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
        "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

        *InDIYana event website*

        Photobucket pages:
        https://app.photobucket.com/u/wolf_teeth_speaker

        My blog/writeups/thoughts here at PE:
        http://techtalk.parts-express.com/blog.php?u=4102

        Comment


        • #34
          I've been simulating various configurations of RS drivers, and heavily focused on the RS100 series drivers to use as my mid-range, or possible mid+high range drivers for a HT rebuild. This build log provides tons of inspiration and interesting tidbits. I'm thinking I need to take my next project to the level of getting some measurement gear to do on-baffle, in-room data collection like this. Ultimately I think that is the destination most of us DIY guys are on a journey towards, and this thread may be the inspiration to get me to finally take the plunge. I'm going to have to put up more sound damping in my server room though. I don't think I have the noise floor low enough in the house here to do a good measurement. lol.

          Thanks so much for sharing this project. I really like it!!!
          Pro/Fi Cinema Speaker project: "From the Ashes"

          Comment


          • #35
            Originally posted by mdocod View Post
            I've been simulating various configurations of RS drivers, and heavily focused on the RS100 series drivers to use as my mid-range, or possible mid+high range drivers for a HT rebuild. This build log provides tons of inspiration and interesting tidbits. I'm thinking I need to take my next project to the level of getting some measurement gear to do on-baffle, in-room data collection like this. Ultimately I think that is the destination most of us DIY guys are on a journey towards, and this thread may be the inspiration to get me to finally take the plunge. I'm going to have to put up more sound damping in my server room though. I don't think I have the noise floor low enough in the house here to do a good measurement. lol.

            Thanks so much for sharing this project. I really like it!!!
            I'm glad you're inspired. I try to post the type of info I enjoy reading from others.

            Don't be intimidated by a measurement setup. Although my learning curve was large, learning to measure was a big step in my understanding. You'd be surprised what kind of meaningful data you can get from terrible setups. I have a train track across the street. My noise floor is abysmal. But I can still measure accurately. The key is understanding what is important and knowing what settings to use when and at what level.

            Cheers,

            Comment


            • #36
              That set of drivers look like they are made for each other. A great looking center channel, i hope that it sounds as good as it looks, terrific.

              Comment


              • #37
                Crossovers assembled:

                Click image for larger version

Name:	crossover_s.jpg
Views:	68
Size:	660.4 KB
ID:	1491514

                Comment

                Working...
                X