Event Horizon: a slim, wall-mounted WMTMW

[brianbunge]

Re: Event Horizon: a slim, wall-mounted WMTMW

Well, OK... I honestly hadn't thought of that situation. :eek: My recommendation would be to make the enclosures longer to give the woofers more volume. In this cabinet, the ND105-4 can do some bass, but I can tell they'd like to be set free to dig nice and deep. :D

How about making the cabinet 50"H and just add 2 more ND105-4's per side? ;)

[Jeff B.]

Re: Event Horizon: a slim, wall-mounted WMTMW

Coming soon... to a living room in my house ;)



It uses the Dayton ND105-4 + Dayton ND90 + Dayton ND20FB, all rear-mounted. (Yes I finally figured out a way to take the ugly out of those damned pincushion frames. More on that in a bit. For now, here's a teaser)


This project was an idea generated by my wife. She wanted something slim and wall-mounted for our living room. Believe it or not, she wanted lots of drivers--a mini line array, if possible!
This created a laundry list of challenges:
1. The enclosure had to be small, and maximize its use of space. Anything wider and deeper than 6" was too much. But you can't get too long, either, or it just looks silly. I decided no longer than 32". So, that limits our total box volume to something around 11 Liters, max.
2. There are very few drivers out there that will put out any sort of respectable bass in 11 Liters. A 5" woofer is way too much; a single 5" driver needs that much space on its own to get decent bass. 3" woofers might work, if you get enough of them. But even the venerable Aura-derived NS3 (Dayton ND90) could only get down to the mid-50 Hz range. What's left? 4" drivers; and even those are a push, though there are a few that can get respectable bass.
3. Everything has to be as lightweight as possible. 3/4" MDF creates very heavy cabinets--great for floorstanders, not so good for wall-hanging. Plus, that thick stock eats up valuable interior space: so 1/2" MDF it is. As for drivers, if I could find neodymium motors, that'd be a plus, since they're lighter in weight (this was before the neodymium fiasco we are now witnessing)

One driver I thought would work would be the Dayton ND105-4 and/or the ND90. But I had to find a way to hide those ugly frames. I searched around this board and the internet to see if any DIYers had found ways to mask it, and finally found someone who had the right idea (I apologize that I don't remember who it was. But I remember he had converted an old Minimus-7 to use an ND90 and cleverly rear-mounted the driver with just the right amount of recess so it didn't look silly.) And that's just what I did. I used the ND20FB to complete the ensemble. (Oh, and I just freehand-routered the bits around the nuts--a step which ended up being unnecessary)





.

You have seen these before, haven't you?




I love this approach to dealing with those odd shaped frames.

I also love the name - Event Horizon. Nice job.

[michiganpat]

Re: Event Horizon: a slim, wall-mounted WMTMW

dumb thought, but if you need/want a little more volume, instead of perpendicular sides, could you make the cabinet a trapezoid, with like 15 degree sides? the 5" in front (with a 6" wide baffle as you show) would flare out to 7.3" in the back, and would give you another 50% in volume.

conversely, if you could do the same idea and make them a little shallower to get the volume out of it. (say, 3" internal, with 25 or 30 degree sides)

[Paul Carmody]

Re: Event Horizon: a slim, wall-mounted WMTMW

Paul, looks like a fun system! Do you have ND105-4 measurements (on/off axis) you can share? Looking to compare to some results I took in a JD box.

Dave,
I'd be glad to share some measurements with you. For my projects, I tend to take measurements from a single point on the listening axis, but I can easily go back and take some more of just that driver.

What's a JD box?

By the way, did you measure the T/S of the ND105-4? Did anyone? Usually, Dayton's spec sheets are pretty accurate, but I never verified it with this driver myself.

[johnnyrichards]

Re: Event Horizon: a slim, wall-mounted WMTMW

Paul, this looks like another project that is going to get you some serious email

Well done, so far. Like the concept, like the execution. Sometimes I wish I could talk my wife into letting me go in/on-wall but she likes big speakers:D

[tdv]

Re: Event Horizon: a slim, wall-mounted WMTMW

Paul, nice project. Another option for rear mounting with no exposed screws on the front baffle, just bent up some aluminum clips out of flat stock.
Tim

[Chris Roemer]

Re: Event Horizon: a slim, wall-mounted WMTMW

Dave,
I'd be glad to share some measurements with you. For my projects, I tend to take measurements from a single point on the listening axis, but I can easily go back and take some more of just that driver.

What's a JD box?

By the way, did you measure the T/S of the ND105-4? Did anyone? Usually, Dayton's spec sheets are pretty accurate, but I never verified it with this driver myself.

try

http://techtalk.parts-express.com/showthread.php?p=1705829&highlight=nd105-4#post1705829

[Paul Carmody]

Re: Event Horizon: a slim, wall-mounted WMTMW

Chris,
Thanks very much for that.

I'm a bit disheartened here. I tested the T/S parameters of my ND105-4 last night (attached) and it turns out that Dayton's spec sheets weren't quite what they were cooked up to be.

See, if you use the specs on Dayton's sheets, the ND105-4 models almost exactly like the HiVi B4N. This got me very excited, because pretty much no other driver out there models like the B4N in terms of squeezing out a big bass sound out of a small box (the only exception I know of is the Seas Excel W12CY001).

I mean, it's not the end of the world... the ND105-4 just needs a little bit bigger box than I'd planned. It models very similarly most of the other great 4" or 4.5" woofers (Dayton RS125, Seas L12, TB W4-1720, etc) That is, it needs at least 5.5 Liters to really come to life.

So... back to the project at-hand. I did some RTA measurements of the Event Horizons, and I'm getting an F3 in the upper 50 Hz range. Is this workable? Of course. I was just hoping for an F3 in the mid 40s. But I guess if I really want that kind of bass response, I'll have to use the Seas Excel W12 :rolleyes: or do a HiVi version.

[KLR]

Re: Event Horizon: a slim, wall-mounted WMTMW

Paul, nice project. Another option for rear mounting with no exposed screws on the front baffle, just bent up some aluminum clips out of flat stock.
Tim

Wow! Nice work!

[Erich H]

Re: Event Horizon: a slim, wall-mounted WMTMW

Signing up for the thread.

These look great!

[lostboy77]

Re: Event Horizon: a slim, wall-mounted WMTMW

So... back to the project at-hand. I did some RTA measurements of the Event Horizons, and I'm getting an F3 in the upper 50 Hz range. Is this workable? Of course. I was just hoping for an F3 in the mid 40s. But I guess if I really want that kind of bass response, I'll have to use the Seas Excel W12 :rolleyes: or do a HiVi version.

In 4.25l, with a tuning of 50Hz, I am getting an F3 of 48.75Hz. This alignment had a gradual and smoothly increasing roll off. Correct me if I'm wrong, but being on wall speakers, the added room gain should pull this up to an actual F3 nicely in the low 40s, maybe even the high 30s. If you add 6dB to 40Hz (typical of close boundary room gain) you are 2dB down from reference.

These may to better than you think.

[DIYNut42]

Re: Event Horizon: a slim, wall-mounted WMTMW

These are looking great Paul! Bet they will really sing. I'm one that doesn't care for the ND Driver frames as well. Rear mounting these makes em look good. I ended up making a 1/8" thick plastic faceplate for my AviaTrix MLTL's just to hide the frames. Actually a pic of one of them is in my avatar. Guess I should probably get that build thread up soon... :rolleyes:

[DDF]

Re: Event Horizon: a slim, wall-mounted WMTMW

Dave,
I'd be glad to share some measurements with you. For my projects, I tend to take measurements from a single point on the listening axis, but I can easily go back and take some more of just that driver.

What's a JD box?

By the way, did you measure the T/S of the ND105-4? Did anyone? Usually, Dayton's spec sheets are pretty accurate, but I never verified it with this driver myself.

Hi Paul,
Sorry, I must have missed this post first time around. "JD" = "Jack Daniels" carboard box (it was done quickly!), but it was actually a Vodka cardboard box (less coloured sound contribution? )

Here's what I found:
"Title: Measured Data"
"Method: Box-loaded (20.00 liters)"
"DCR mode: Measure (-0.02 ohms)"
"Area (Sd): 235.00 sq cm"
"Series resistance: 75.75 ohms"
"Stimulus level: 1.00 volts"
0.134 "RMSE-free Ohms"
71.212 "Fs Hz"
3.951 "Re Ohms[dc]"
31.492 "Res Ohms"
4.748 "Qms "
0.596 "Qes "
0.529 "Qts "
0.488 "L1 mH"
0.535 "L2 mH"
1.489 "R2 Ohms"
0.127 "RMSE-load Ohms"
0.000 "Vas liters"
0.000 "Mms(Sd) grams"
0.000 "Cms(Sd) æM/Newton"
0.000 "Bl(Sd) Tesla-M"
0.000 "SPLref dB[Re]"
0.004 "Rub-index "

Curious if you saw the same break up signature.

Thanks!
Dave

[fastbike1]

Re: Event Horizon: a slim, wall-mounted WMTMW

I know they have great bass, but the Sd in your measurements is more typical of an 8" driver. It should be around 51 rather than 235.

Hi Paul,
Sorry, I must have missed this post first time around. "JD" = "Jack Daniels" carboard box (it was done quickly!), but it was actually a Vodka cardboard box (less coloured sound contribution? )

Here's what I found:
"Title: Measured Data"
"Method: Box-loaded (20.00 liters)"
"DCR mode: Measure (-0.02 ohms)"
"Area (Sd): 235.00 sq cm"
"Series resistance: 75.75 ohms"
"Stimulus level: 1.00 volts"
0.134 "RMSE-free Ohms"
71.212 "Fs Hz"
3.951 "Re Ohms[dc]"
31.492 "Res Ohms"
4.748 "Qms "
0.596 "Qes "
0.529 "Qts "
0.488 "L1 mH"
0.535 "L2 mH"
1.489 "R2 Ohms"
0.127 "RMSE-load Ohms"
0.000 "Vas liters"
0.000 "Mms(Sd) grams"
0.000 "Cms(Sd) æM/Newton"
0.000 "Bl(Sd) Tesla-M"
0.000 "SPLref dB[Re]"
0.004 "Rub-index "

Curious if you saw the same break up signature.

Thanks!
Dave

[superspeeder]

Re: Event Horizon: a slim, wall-mounted WMTMW

Nice work! I plan to do something similar with my HT speakers, rear mounting them to hide those frames...

I was wondering if PE would consider releasing an upgraded version of these drivers for a bit more $ and a nice cast frame, but the introduction of the "still ugly" ND91 seems to have put that dream to rest.