Matrix - Reloaded.

[rhubarb9999]

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.

[ligs]

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

[scottsehlin]

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.

[rhubarb9999]

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.

[rhubarb9999]

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

[scottsehlin]

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.

[IBM5150]

Re: Matrix - Reloaded.

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