Dayton Audio ND105-4 ( Aura NS4 ) for computer monitors - MTM or TMM or TM ?

Are there any draw-backs to using an MTM for computer speakers?
Should I use a small neo-tweeter in the middle or an XT25 (104 mm flange) tweeter?

Is a 2.5 way better with the Aura's (8 ohm)?
Or just forget both and build a TM 2-way with the Aura's or Dayton's?
Are there any differences in the drivers other than the impedance?
 
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jReave

Member
2012-10-30 4:34 pm
For computer speakers, I would think that box size would be a key consideration and then after that, how low you want them to play and how loud.

Run the Aura NS3 and the Dayton ND90, ND91 and ND105 through a box sim program to see what best suits your situation. The NS3 will be the cheapest, the ND91 suits the smallest box and the ND105 goes the lowest but in the biggest box.

Obviously, using 2 drivers will double your box size but also give you extra SPL capability that you may not actually need for near field computer listening.
 
I think I might have to scrap this design.
Once I start planning a build more and more, I realize it takes more effort than I thought to build the pair of speakers and then I feel like if I use drivers that are this cheap it should take me only 1-2 hours to build some speakers.
If I'm going to put more time than 1-2 hours to build speakers, why start with cheap drivers.
The crappy frame is what especially gets me.
I have to do mental gymnastics to figure out how to mount this garbage in a descent way.
 
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Clueless

The frames are challenging, but these aren't cheap drivers. They're well built and give surprising performance. There are a number of successful designs and builds if you'd have searched.

What gave you the idea you could build anything decent in 1 to 2 hours?

Oh, you could rear mount the drivers.

The garbage comment is clearly ignorant.
 

Ronion

Member
2013-04-13 7:45 pm
A line array of small full rangers sounds like a better idea. I've never built a speaker in a couple. A couple months has been more my pace. It's part of the attraction of just buying completed products. To bad they never seem to make exactly what you want.
 
Guess I kind of lost my patience with this driver.
If you don't like the word garbage, I can do flimsy. Which to me means garbage.
But they are cheap. So I guess the adage "you get what you pay for" holds true.
I thought the Aura was built a little better than the Dayton, but I'm not sure.
I did model the drivers, the Aura drivers have the same FR in a box the same size as the Daytons, but the Auras need a port twice as long due to having double the BL, I assume.
And I figure a higher BL couldn't hurt. Also not so sure about that one.

The main problem is I can't route out the back of baffle with the box construction I have in mind. I planned on routing a single shape and stacking pieces of wood onto each other.
I think my new idea is just to build a 2-way with a 5-7 inch woofer and a tweeter, but it's going to be so close to my head the of axis response is going to suffer.

I guess I'm just into rugged drivers, especially frames. I found a lot of HiVi frames to be very well built.
Except for a few ones made with stamped steel frames.
 
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jReave

Member
2012-10-30 4:34 pm
I think the greatest benefit of the drivers you're looking at is their large xmax and how low they play in relatively small boxes. The frames however are definitely a place that they are cutting their costs. I've got 6 of the ND91-8 sitting around waiting for me to do something with but I'm probably going to beef up the frames with fiberglass as a first step. Either way, I will be rear mounting them.

So first things first I'd say is defining your design parameters - f3, sub or not, vented or sealed, costs, level of desired sound quality, time allotment, etc., etc.

Also, there is no reason that a translam (stacked layers of high quality plywood) can't be built with a front baffle. The speaker that popularized this style used both a front and rear baffle attached with threaded rods. See below. Btw, I would strongly recommend a router table for this type of construction. Makes things a lot easier.

SB Acoustics and the Peerless HDS Nomex series are some other high quality good value drivers with solid frames if they are available to you at a good price.
 

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I think the greatest benefit of the drivers you're looking at is their large xmax and how low they play in relatively small boxes.

Yes, and they are narrow.
I also have the following drivers, but they all have a drawback since I'm using these speaker for my computer:

http://www.lautsprechershop.de/pdf/wavecor/wavecor_wf182bd02.pdf
Overview of W5 Drivers_HiVi,Inc
Silver Flute W17RC38-08
Dayton RS125-08


Mostly they all need a rather large box if ported and they need a wide baffle.
Wavecor in a sealed box might not be bad. The Wavecor might be good in a sealed box, but I was hoping to cross my sub over at 50 Hz. Actually,
I will be using my computer as a cross-over so a higher frequency might be fine.

What total seemed to kill my MTM with my Dayton's or Aura is that I have to chamfer (spelling?) the back and I can't get to it. Here is my box design cross-section:
You know now that I "drew" it. I kind of don't like it :D
There will be a metal grill covering the top and front.
 

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jReave

Member
2012-10-30 4:34 pm
Why exactly do you want to curve the baffle like that for a pair of near field computer speakers? Seems like nothing but trouble to me with no real advantages other than perhaps a cool aesthetic?? And whether or not you front or rear mount the drivers, the inside of the baffle should be chamfered in either case.

Actually, even front mounting a driver on that curved surface is going to be a real challenge, more so as the driver gets larger. Curve the sides if you must, angle the front baffle so that it's on axis to your listening height if you want, but whatever you do, keep it flat.

You have a sub - why not use it and xo at about 80Hz? The speakers then can be as small as possible. Then you don't need to use a 7" driver like the Wavecor as a computer speaker. The Dayton RS125 is a nice little unit but sealed its f3 is up around 113Hz. Kind of high. Ported it goes lower but it only has 4mm of xmax.

Seal the ND105-8 in about 4 or 5L and you get an f3 of about 77Hz with a Qtc between .76 to .8 or so. Xmax is also 4mm but it's got a peak to peak excursion of 20mm. That means SPL up to 100dB in this alignment. That's louder than you need it. Just change your box design and rear mount them. I think you might be pleasantly surprised.

Save the Wavecor and Dayton for another build. That perhaps might be the basis for a nice 3-way.

Cheers
 
I thank you for the advice, but don't ever say
That's louder than you need it.
:rofl:

I kind of want to use the Aura because it has double the BL as the ND105-04 (4 ohm), but I don't know if it has a big affect on the sound or transient response.
I can see how the Dayton will go lower in a sealed box.
Oops, I just remembered it doesn't matter because the kx drivers I use for my computer have all kinds of EQ possibilities.
If I do an MTM I don't know whether to wire the Aura's for 16 or 4 ohms impedance?
 
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jReave

Member
2012-10-30 4:34 pm
I appreciate the humor but the danger to your hearing is real. Treasure it and protect it while you have it cause once it's gone, it's gone. Trust me when I tell you "we're only immortal for a limited time " - this year I lost most of the hearing in 1 of my ears after years and years of way too much loud music. Too bad I can still hear the ringing louder and more persistent than ever. I can still enjoy music but stereo is gone. Imaging, soundstaging - toast. Surround sound? Collapsed to 1 side of the room only. So do what you will of course, but you should be aware of the potential dangers and know that they are real.

Now, enough of that.
I assume you already have the Auras because the are no longer available.
Which version exactly do you have?

I just modelled the NS4-255-8F, aluminum cone, virtually identical to the Dayton ND105-8. Well almost, cause it only goes down to about 103Hz when sealed in 1.5L. And if you are so concerned about transient response then you should probably go sealed. So if your sub can go that high, then that's an even smaller box than with the ND105. Two of them MTM in 3L would probably work nicely.

Wiring depends on your amp and the xo implementation. Minimum impedance looks like about 6ohm, so paralleled is going to be closer to 3ohm minimum which many amps can handle. Series min is going to be about 12ohm which I think pretty much all can handle. Maybe someone else can concur on that? The xo may result in slightly lower min impedances so you might want to work each one out before deciding. Of course, parallel gets you 6dB more efficiency than series so that's the one most people favor. Do you have a nice small tweeter picked out so you can keep the center to center spacing as tight as possible?
 
I tried to use an existing plastic enclosure that contained a driver that had the same exact frame dimensions as the Dayton and Aura. The case was cheap and flimsy just like the driver's frame, so I decided to reinforce the inside with fiberglass. I hadn't worked with fiberglass in about ten years and it is still awful, so I threw the enclosures away after ruining them with my fiberglass job.
Now that I think about it the flimsy enclosures fit the flimsy frames pretty well.

Anyhoodle, as you can tell I can't get over the frames, so I think I'm going to move onto the Silver Flutes, unless some one has a good reason not to. Also I don't know whether to use a neo-tweeter with them or standard tweeter. And then I have standard tweeters that I can cross-over at 2 KHz and another one that I can cross-over at 3 KHz. The tweeter crossed over at 3 can play higher with better off-axis response at the top, but the one cross-over at 2 KHz will match the off-axis response of the woofer better.
 
Is a 2.5-way bad for near-field listing?
I was thinking of putting 1" dome tweeter and two 7" drivers about 1 meter away from my head. I think the .5 woofer would be crossed over at 100-300 Hz but I'm not sure.

Actually I kind of figured out how to cross the .5 woofer over at 100 Hz or lower, but I don't know if it's a good idea. I would just EQ the top woofer.
Also I'm concerned with the top woofer playing midrange frequencies and bass.

I can also go with tweeter 4-7 inch mid and 10" woofer for a close-range setup.
 
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Is a 2.5-way bad for near-field listing?
I was thinking of putting 1" dome tweeter and two 7" drivers about 1 meter away from my head. I think the .5 woofer would be crossed over at 100-300 Hz but I'm not sure.

Actually I kind of figured out how to cross the .5 woofer over at 100 Hz or lower, but I don't know if it's a good idea. I would just EQ the top woofer.
Also I'm concerned with the top woofer playing midrange frequencies and bass.

I can also go with tweeter 4-7 inch mid and 10" woofer for a close-range setup.
You would need to be further away for proper integration.

Better for nearfield would be an active fast system with a helper tweeter, BG Neo planars etc

The level attainable at this distance can easily destroy your hearing in short order (in hours if not minutes). jReave is correct, protect your ears or pay the piper.