Slim Speakers using Aura 3" drivers

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Alright, so here's the deal. I want to build a nice sound system in a very small package. Not looking to spend a fortune. I want to build a set of very compact bookshelf speakers with a great frequency response. A bit of a long shot, but hear me out.

This will be a gift for my father in law who's birthday is coming up in a month, who also just finished a difficult and stressful treatment for lung cancer. He's on his way to recovering now.

Someone recently introduced me to madisound.com, and I was pretty surprised at the prices and specs some of these speakers had. These in particular:

https://www.madisound.com/store/product_info.php?cPath=45_241_282&products_id=1503
https://www.madisound.com/store/prod...oducts_id=1372

So that got me thinking, I would love to make a little compact multimedia desk speaker system. What if I were to create two slim towers to be placed on his desk or on a bookshelf using 2-4 of those 3" drivers and a nice tweeter in the center. Something in either a completely sealed or a ported box. This could be run easily off of his current receiver.

I will need help figuring out box specs, and finding a suitable amp. What I'm going for here is big sound in a seemingly small package. I like these drivers in particular because of their high excursion capabilities and their low frequency response.

I've searched through this forum and found a few projects, but they all came short of my plans in either size, number of drivers, or what have you.



I think I've come to the right place, so here's what I need to know to make this happen:

I need help with box specs. I don't have imaging software or the experience to figure this out on my own. I've built a dozen subwoofer boxes, but nothing like this. This is my first time. I read reports of someone who had screeching issues and fixed it somehow. Basically what I need is someone with some experience.

I also need help with design. I don't know what works best, but my plan was to have all 4 of these drivers front firing with a port in the rear or at the bottom. If the needed box would be too large, I could easily cut that down to 2 drivers. I'm going to for as slim as possible, with depth and height being the question.

I also need help choosing a driver. I'm looking at either the Hi-Vi or the Aura drivers and I'm not sure which to pick. I'm leaning toward the Aura due to excursion capabilities alone, but the size of that magnet makes me wonder. I have no idea how speakers work but the Hi-Vi drivers look a lot more beefy.

Anyways, any feedback and help would be greatly appreciated.
 
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Administrator
Joined 2004
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I have moved this over into the full range speaker section. I think the response will be better here. Good luck with the project. Don't worry about the magnets. The HiVi uses a shielded ceramic type while the Aura uses a neodymium so it will be smaller. I would guess the HiVi is better at the highs and the Aura better at the lows but I don't know the Aura driver. The HiVi is good.
 
Being that his are sealed you just keep the same internal volume if you wish to change the shape slightly. Double the existing volume each time you double the drivers and Bob's your Uncle.

That's a good start.

I did look at the frequency response graph on the madisound site, and in comparing the Hi-Vi B3N he used and the Aura NS3 that I'm also considering, I'd also like to determine which would be more suitable for this application. The NS3 appears to have a much higher excursion.

One thing I'll definitely need help with is the filter that is mentioned. I'm fairly new to electronics in that aspect and will probably need someone to explain it a bit since I'm not even sure what it does to begin with.
 
The filter tailors the sound to make it "smoother and straighter". It's also somewhat complex for a beginner unless you have done a little soldering in the past.. That being said, you may be satisfied without the filter but Zaph is pretty good at these things and likes to have all his cards in order.

I refurbish laptops as a side business and that often requires de-soldering and re-soldering power jacks. I'm more concerned with the theory behind it, what parts are needed, and how to hook them all up.

I just thought of something; that it may be nice to have a built in crossover with a switch that can turn it on or off. That way, he can turn off the crossover when he has a sub hooked up, or turn it off when he doesn't.

Also, when using more than one driver, does each driver need a filter, or just one of them?

Of topic random question: is there somewhere to buy dust caps for subs? I have a 12" Advent sub that he'll be using with these and the dust cap fell off one day and I lost it.
 
Sorry if this is a lot at the same time.

I'm also going to be considering the following drivers:

Dayton Audio RS100-4 4" Reference Full-Range Driver 4 Ohm
https://www.madisound.com/store/product_info.php?products_id=8585
MCM Audio Select 4" Aluminum Cone Die-Cast Woofer with Rubber Surround - 20W RMS | 55-3853 (553853) | MCM Audio Select

My only gripe is that they're larger and more expensive, but it may be worth using them instead of the 3" drivers given the reports I've seen of distortion at lower frequencies.
 
I refurbish laptops as a side business and that often requires de-soldering and re-soldering power jacks. I'm more concerned with the theory behind it, what parts are needed, and how to hook them all up.

I just thought of something; that it may be nice to have a built in crossover with a switch that can turn it on or off. That way, he can turn off the crossover when he has a sub hooked up, or turn it off when he doesn't.

Also, when using more than one driver, does each driver need a filter, or just one of them?

Of topic random question: is there somewhere to buy dust caps for subs? I have a 12" Advent sub that he'll be using with these and the dust cap fell off one day and I lost it.

Who is 'he' ??:p
That filter is properly an equalizer circuit , the purpose of it is to attenuate a little some frequencies in the mid-treble band . WHY ? I really don't know !:D ( some say that the drivers 'shout' ,so it is better to make 'em behave good).
When using two drivers ,the issue may disappear...surely it will be forgiven because output levels doubles ! Speakers ,having a coil made of steel ,represent a resistor ,so Ohm's law says that when two (equal) resistors are paralleled ,resistance halves . You cannot parallel as many speakers as you want because amplifiers don't like loads that are near to a short circuit .
 
Who is 'he' ??:p
That filter is properly an equalizer circuit , the purpose of it is to attenuate a little some frequencies in the mid-treble band . WHY ? I really don't know !:D ( some say that the drivers 'shout' ,so it is better to make 'em behave good).
When using two drivers ,the issue may disappear...surely it will be forgiven because output levels doubles ! Speakers ,having a coil made of steel ,represent a resistor ,so Ohm's law says that when two (equal) resistors are paralleled ,resistance halves . You cannot parallel as many speakers as you want because amplifiers don't like loads that are near to a short circuit .

He being my father in law.

I'm aware of the impedance issues. I'm not entirely sure what his receiver is mostly capable of in regard to impedance, but my guess is that its going to be either 4 ohms or 8 ohms.

When my last post gets approved, you'll see what other plants I am considering. At this point I'm heeding the warnings on zaph's reviews in regard to the 3" drivers I was considering. I want these to be usable without a sub, and the Hi-Vi B3N's do not have enough low end reproduction, while the NS3's are described as having "Merely average or high harmonic distortion throughout it's entire usable range." This is drawing me away from 3" drivers and over to 4" drivers.

I may end up using 4 of these (2 per cabinet):
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-378
 
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frugal-phile™
Joined 2001
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My preference would be for the Aura as far as cheap 3" go.

The Fountek is a step up in performance... a single one in a set of uFonken or 2 in uFonken^2 (adjusted port spacer -- what i have in my office right now) will be a lot "bigger" than you expect, the 4" get you into a different kind of project -- a single Mark Audio CHR70, CSS EL70 or Fostex FE127 would be my top choices for a small box with a 4" -- no tweeters required on any of these

dave
 
My preference would be for the Aura as far as cheap 3" go.

The Fountek is a step up in performance... a single one in a set of uFonken or 2 in uFonken^2 (adjusted port spacer -- what i have in my office right now) will be a lot "bigger" than you expect, the 4" get you into a different kind of project -- a single Mark Audio CHR70, CSS EL70 or Fostex FE127 would be my top choices for a small box with a 4" -- no tweeters required on any of these

dave

Can you comment on the Aura as far as how it sounds? Have you heard these in a box before? I kept reading on Zaph's site about their harmonic distortion, as if I know what that means. Would you say these would sound "good" when used as pairs with a tweeter in each cabinet?

How would you compare a single Mark Audio CHR-70 to a pair of the Aura NS3's?
 
frugal-phile™
Joined 2001
Paid Member
Can you comment on the Aura as far as how it sounds? Have you heard these in a box before?

They sound decent. Not as much downward dynamic range or the sparkle of the Fountek (or the legendary FF85K).

I had mine sealed and i heard Gregg the Geeks BR with helper tweeter (the $1 ApexJr audax tweeters). He was able to get a staggering amount of bass out of them (for a 3").

Still, i'd spend the same money on fewer Founteks, going for quality over quantity.

harmonic distortion, as if I know what that means

Geddes has shown it to be pretty meaningless.

How would you compare a single Mark Audio CHR-70 to a pair of the Aura NS3's?

The CHRs are in a whole 'nuther quality category. A single pair of those would out gun any of the 3" mentioned (in any quantity). They are, however, scarce on the fround in NA (i have some tarted up ones), with probably at least 8 weeks before we see more (they are being made soon). The EL70 (a paper cone based on the same basket and similar powertrain, is plentiful).

dave
 
They sound decent. Not as much downward dynamic range or the sparkle of the Fountek (or the legendary FF85K).

I had mine sealed and i heard Gregg the Geeks BR with helper tweeter (the $1 ApexJr audax tweeters). He was able to get a staggering amount of bass out of them (for a 3").

Still, i'd spend the same money on fewer Founteks, going for quality over quantity.



Geddes has shown it to be pretty meaningless.



The CHRs are in a whole 'nuther quality category. A single pair of those would out gun any of the 3" mentioned (in any quantity). They are, however, scarce on the fround in NA (i have some tarted up ones), with probably at least 8 weeks before we see more (they are being made soon). The EL70 (a paper cone based on the same basket and similar powertrain, is plentiful).

dave

I wouldn't mind upgrading to the CHR and building a better speaker, but I don't have 8 weeks and shipping from Hong Kong is $35.

I think for the time frame I have and for what's available, I'm going to go with either the Aura NS3's or the HiVi B3N's. If you know of anywhere that has the NS3's cheaper than madisound, please let me know. They seem to be out of stock on partsexpress. However, the B3N's are on sale now and I can get 8 of them for $76.57 shipped with a $5 coupon code. I would only be able to get 4 of the NS3's from madisound for around the same price as 8 of them would take me well over $100 shipped.

Given these two options, which would you take? 4 NS3's or 8 B3N's? Do you think that 4 B3N's would have enough bass to be enjoyable without a sub?

According to this calculator:

http://www.linearteam.dk/default.aspx?pageid=newdriver

Punching in the numbers with a vented enclosure for 4 of these would produce a good frequency response all the way down to 35hz.
 
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I'd get a pair of EL70s.

dave

I'd really prefer to stay clear of paper cones. Just something about them I really don't like.

I think I've pretty much decided on what I'm going to do.

Dayton Audio ND105-4 4" Aluminum Cone Midbass Driver 4 Ohm

I've kind of realized that paying $12.50 for an NS3 is a bit of a bad deal when you could get this 4" dayton driver and the NS4's are discontinued. 4 of these and a tweeter would come near the same price as 8 of the B3N's. I'm really space constrained here but it seems that going with a 3" driver is too much of a sacrifice in quality.

So basically what I'm looking at now is two of the Dayton midbass drivers with a tweeter. How does that sound? I've seen people tuning the ports on these to as low as 10hz without any issues at all, so I should be able to work at around 45-50 very easily with more output. Any thoughts? Opinions? I'm still going to try to make these as slim as possible, but at least now they might actually sound a lot better.
 
Interesting about the paper ... my preference is usually for paper.

That Dayton is a 4" version of the Aura @ Madisound. I've been tempted to try it sometime. The cones on these -- if the same as the 3" -- are aluminum foil & plastic sandwiching a paper core.

dave

I don't know, maybe its just me. In any case, I've watched some videos of this driver and its excursion is quite unreal. There are a few reviews on partsexpress where people have mentioned tuning these to 40hz and getting great output out of them.

So what do you think then? Is this something that can be done in a fairly small sized enclosure, or would I need something large for these?
 
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