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Matrix - Reloaded.

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  • IBM5150
    replied
    Re: Matrix - Reloaded.

    Originally posted by lemmalone View Post
    After a surprisingly long time I nearly have the Blue Pills done. Very, very nice speakers, especially the mids and highs. I made baffles and attached them to enclosures from old Acoustic Research AR4x speakers. I still have to fill the counterbore holes and brace the boxes. Also, as Scott had mentioned to me, they play pretty low but not loud, so I'm considering sub options. Pictures attached, although the speakers came out much better than the pics. Just for fun I include pictures of the speakers on their stands--the one with the white grill cover is an Acoustic Research AR2AX and the one with the drivers visible an Infinity Qb. Thank you very much Scott for the design and the help. I really appreciate your sharing your expertise; I'm hearing alot more music now!
    Is there a write-up on this design, baffle dims, box Vb, Fb, XO? Looks interesting, nice job!

    Thanks,

    Eric

    Leave a comment:


  • scottsehlin
    replied
    Re: Matrix - Reloaded.

    I used the stock back cup for the Neo3PDR. For the Neo 8, I did a rectangular cutout through the full 1.5" baffle. I then glued another piece of 3/4" mdf on the inside surface of the baffle to cover the cutout, which gave me a 1.5" deep chamber which I stuffed loosely with polyfill. When I ran the lead wires out the back of the chamber, I did not seal the holes (intentionally). My goal was to create a slight aperiodic vent to work against any possibility of pressure developing inside the chamber (which the Neo8 would not like). If you do deviate significantly from that approach, I would expect a difference in the low end response. Since you will be crossing over actively to a different woofer, that shouldn't be an issue. There may be some differences up higher as well, but I think they will be more subtle if there are any at all.

    Leave a comment:


  • rhubarb9999
    replied
    Re: Matrix - Reloaded.

    Hi Scott,

    I have a quick question. I have started cutting the baffles for the Neo3/Neo8 combo. I am putting the woofers in separate cabinets so the Neo's cabinet will be small (something like 5"w x 13"h x 10"d). Did you have any stuffing behind the Neos? Did you use the back cups?

    Also, I noticed that you used a 1 1/2 inch baffle and front loaded the drivers. I am only using a 1/2" baffle and inset the drivers for rear mounting. Since I don't have the "tunnel" that you had, do I need to worry about compensation in the crossover?

    Thanks

    Leave a comment:


  • rhubarb9999
    replied
    Re: Matrix - Reloaded.

    Interesting that this came up. I will be scavenging parts from my Cryolite build to create two different systems sharing the Neo3/Neo8 passively crossed top section.

    My plan is to use the Neo3/Neo8 top section with two different bottom sections. My office is a long narrow room with the speakers at one end. The Neo8/Neo3 will be sitting on top of a Hivi D8.8+ in its own cabinet. It will be actively crossed around 700Hz with a MiniDSP.

    In my big 'listening room', the Neo3/Neo8 will be on top of a sealed RS-180 crossed at 700 Hz to the top and 100Hz to a pair of NHT1259s on the bottom. This will be tri-amped through a modified DCX2496.

    The top section will move between rooms. I usually only get to crank up the big system on weekends (the room is right under the master bedroom) .. so during the week, the Neos will be used for low level listening in my office.

    That's the plan anyway. Hope to cut wood his weekend.

    Leave a comment:


  • scottsehlin
    replied
    Re: Matrix - Reloaded.

    That's a somewhat puzzling design. I would not think the Neo8 would need an upper mid to go along with it - the only reason I can possibly think of is to improve the vertical dispersion. The mids do tend to drop out a little on the Neo8 when you get above or below the height of the driver, which I tried to alleviate by having shallow slopes and a relatively narrow frequency range that the Neo8 is covering.

    Conversely, it doesn't seem that the Neo8 and 1259 would meet up very well - as it would be hard to push the Neo8 below about 700 Hz. and it would be less than optimal to run the 1259 up there.

    Now if you wanted to take my design and add a larger woofer (using the RS150 as a lower mid) - that would have a lot of potential.

    Leave a comment:


  • ligs
    replied
    Re: Matrix - Reloaded.

    Here is a documentation of a pair of handsome 4-way speakers using BG Neo8 driver. Giussani Research DELTA 4R5. Maybe someone can update this design because I see a lot of interest in the midrange quality of BG Neo8(or PDR)
    http://web.mclink.it/MC0419/rldelta45/index_en.html

    Leave a comment:


  • rhubarb9999
    replied
    Re: Matrix - Reloaded.

    I looked at the specs again for the Neo8PDR and it looks like the drop in sensitivity is just above and below my crossover points, so I decided to go with your original model of a 0.27 mH inductor, 1.5 ohm resistor, and 15 uF capacitor. I actually got a 1 ohm and a .5 ohm resistor so I can try both 1 and 1.5 ohms and see what I like better. I tend to like the 'BBC dip' so padding down the Neo8 a little more may be just the ticket.

    Also, the only source for these will be from a PC so I will have EQ available to flatten them out if need be.

    Leave a comment:


  • scottsehlin
    replied
    Re: Matrix - Reloaded.

    If the only difference between the Neo8 and Neo8PDR is a 1.5 dB across the board drop in sensitivity, then I would shoot for 0.2 mH inductor, 1 ohm resistor and 18 uF capacitor for a Neo8PDR low pass filter.

    Leave a comment:


  • scottsehlin
    replied
    Re: Matrix - Reloaded.

    That 1.5 dB will require reducing the value of the 1.5 ohm resistor. I would guess you will wind up somewhere between 0 and 1 ohms. I could try to sim a little further by dropping the Neo8 level by 1.5 dB and leaving everything else the same to see if there would be any impact on the other components.

    Leave a comment:


  • rhubarb9999
    replied
    Re: Matrix - Reloaded.

    Thanks very much for re-modeling it.

    One question .. I have the Neo8PDR version of the driver which is 1.5dB less sensitive that the non PDR version. Should the Neo3PDR be attenuated to match?

    Leave a comment:


  • scottsehlin
    replied
    Re: Matrix - Reloaded.

    Originally posted by rhubarb9999 View Post
    I am interested in using the top half of this design as well. However, I would like the crossover between the woofer and the Neo8 to be active.

    I am not that familiar with passive x-over design. Any idea what would be removed from the Neo8 crossover to allow it to be 'full range' up to the 3.5K crossover to the Neo3?
    In theory, the only component that needs to be removed is the 10 uF capacitor that is between the 1 ohm resistor and the 0.47 mH inductor in the schematic. I looked at a simulation of that, and in reality going from a 3 way crossover to a two way with the Neo8 and Neo3PDR, I would recommend changing the values of the remaining 3 components. A 0.27 mH inductor, 1.5 ohm resistor, and 15 uF capacitor should give a response very close to the original 3-way.

    Leave a comment:


  • rhubarb9999
    replied
    Re: Matrix - Reloaded.

    I am interested in using the top half of this design as well. However, I would like the crossover between the woofer and the Neo8 to be active.

    I am not that familiar with passive x-over design. Any idea what would be removed from the Neo8 crossover to allow it to be 'full range' up to the 3.5K crossover to the Neo3?

    Leave a comment:


  • scottsehlin
    replied
    Re: Matrix - Reloaded.

    That is the main issue with the RS150's. The bass does fill in reasonably well at home.

    Leave a comment:


  • johnnyrichards
    replied
    Re: Matrix - Reloaded.

    I keep meaning to post here, that I really enjoyed the iteration of these at Indy. I would have liked to hear them in a smaller room, as the bass kind of got lost in the conference room.

    Leave a comment:


  • ligs
    replied
    Re: Matrix - Reloaded.

    Just to post a picture of the crossover.
    Both coils are 12 AWG air cored. All capacitors are films type(TRW, Relcap and Madisound buyout), resistors are MOX type.
    Attached Files

    Leave a comment:

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