How good are the cheap fullrange drivers?

hedphones

Member
2013-02-11 3:25 pm

Jay

Banned
2003-02-11 9:02 am
Jakarta
THE DRIVER. Multimedia speakers rarely used good quality drivers. The Fountek looks a lot better to me even tho I have never heard it. Fullrange is often a better option than multi-way in low price level such as this.

THE AMP. Class-A amp is best to hide cheap speaker deficiencies and display the midrange strength that will justify the lack of bass from the driver. But is expensive and not practical. So common option is chip amp which sound good (low THD) at listening power and at selected speaker load. At 5W output power, my favorite is TDA2030A (the chip can be coupled with bipolar output if 7W is needed). But there are better discrete options but you have to search and need to have some skill.

THE BOX. Very important in this game. You want a vented box, especially with driver having Fs of 105Hz. Many multimedia cut the cost down by using plastic box (plastic is easy to form to look good) which sounds boxy. You can do better with DIY. Expensive multimedia speakers use aluminum box.
 
You can get a lot out of a small speaker with a little ingenuity. A Cornu spiral comes to mind as does a downsized version of planet10's FHIII. They have both been done recently and can be made from foam core board and then dressed up quite nicely. It really comes down to box size. Are these going to be actually on your desk? If so, both of those are eliminated, if not you might start thinking about them.
 
The 15 W amplified boxes ranging from 69 to 99 €, they both employ a
tweeter. The definition given by a 1"dome is unreacheable by larger drivers.
:cool:
One may argue that for the very high frequencies given their short wavelenght
also from the apex of the dome you'll hear 'discrepancy' ( interference) versus the sound emitted from the base ...:rolleyes: But that's academic ....
 

hedphones

Member
2013-02-11 3:25 pm
Thanks for the great responses, and also the Logitech X140 speaker link, very good read and surprised of their performance. They seem to use tangband drivers in them.

To add some more detail;
1. I would use these drivers with some dipole subwoofers, so will cross over at 100-200hz, I don't need any much bass from these tiny speakers. Was planning to build the enclosures of metal actually, but don't have any plans yet.

2. I will use minidsp for the crossover, so I think I can also eq the drivers with that if needed.

What I want is basically very accurate midrange, with decent? highs that would at least be better than some cheapo multimedia speakers..
 
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Hi Hedphones.

I work with the Fountek FR88EX and find it to be an excellent driver, but I do use a tweeter on it. The problem as with all full range speakers is beaming if you don't employ a 2 way. Some don't seem to care, but I think building good speakers is all about controlling directivity.

The Maudio AV30 is a speaker I bought because it received good reviews, and I wanted to know what the competition is doing. It superficially sounds nice, but the FR is all over the map. Plays pretty loud, though.

Quality wise, I would go for the Fountek with a small tweeter.

On amplification, classD such as the Tripath based Lepai, really punches above its weight. I have no experience with the Lepai, but I know the Sure and 41Hz implementations with the 2020 chip, and you can't go wrong with these. Just add a wall brick PS and you are ready to go.
 
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Hi Hedphones.

I work with the Fountek FR88EX and find it to be an excellent driver, but I do use a tweeter on it. The problem as with all full range speakers is beaming if you don't employ a 2 way. Some don't seem to care, but I think building good speakers is all about controlling directivity.

The Maudio AV30 is a speaker I bought because it received good reviews, and I wanted to know what the competition is doing. It superficially sounds nice, but the FR is all over the map. Plays pretty loud, though.

Quality wise, I would go for the Fountek with a small tweeter.
What do you exactly mean by beaming? Does it mean off-axis coloration or something?

Could you also add more info/pics of the 2-way speaker you made with the EX88? What tweeter did you use and what crossover freq?
 
What do you exactly mean by beaming? Does it mean off-axis coloration or something?

Could you also add more info/pics of the 2-way speaker you made with the EX88? What tweeter did you use and what crossover freq?

With beaming I mean that when a transducer produces frequencies with a wavelength smaller than the circumpherence of the transducer, the way it radiates into space starts to change. Below that frequency, it radiates in full space, but above it, it starts to radiate in an ever smaller bundle. So, beyond this point, the FR can only be flat at one specific listening angle. This limits the sweet spot considerably.

I can't show you pictures of the speakers I made with the EX88 because I have not yet secured the intellectual property on the design. But what I can tell you is that I use this driver in a three way design, crossed over @ 200 and 2000 Hz. The tweeter I use is Vifa OX20SC00-04 3/4" Fabric Dome Tweeter 264-1002. It is small, which means it can be mounted very close to the mid bass driver, and yet it plays very loud. From my own measurements, I established that it has one of the flattest FR´s around of any tweeter, and pretty low distortion <50dB over the range I am using it in. It is available in Europe too, albeit at a higher price

Because I use it in a d'Appolito configuration I took a fairly low crossover frequency, but if used in a 2-way I would probably would move up a bit. Please note I use an active crossover LR 4th order. With a lower order crossover, you will have to move the xover frequency to at least 2.5KHz.
 
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At first glance it looks like irresponsible engineering to cross it over that low. Based on measurements and listening tests, however, I have dared to do it. All tweeters are in a waveguide, some of them just happen to be flat. Mine isn't flat.

The reason being that in the d'Appolito configutation this gives a vertical listening window of around + and - 30 degrees without significant lobing.
 
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I was pleasantly surprised as well by the performance of this little tweeter. In the first listening test with a rough setting I made an error with the DSP, so the tweeter got everything from 200 Hz upwards. It didn't sound quite right, but I really cranked it up to see how loud the thing would go. I measured 100dB @ 1 meter, played for 5 minutes or so, and still didn't fry the tweeter.

Those of you familiar with the Zaph site know perhaps he is not fond of small tweeters, but he did not test this one. The advantages I see in this one are a much better HF performance (it really goes straight to beyond 20KHz, no 1" dome I ever measured did this), and better off axis response.

Yes, I do use to FR's per side with this tweeter, and it can still keep up.
 

hedphones

Member
2013-02-11 3:25 pm
I think I got the idea of that beaming. So the tweeter gives you a bigger sweetspot right?

Fountek FR88 x2 (3" fullrange/woofer)
Dayton ND16FA-6 x2 (3/4" neo tweeter)
Lepai LP2020 (2x~8watts)

Total cost for these parts would be around 80€.

What is the best way to make a crossover for these? Active, DSP, passive? And what frequency would be preferred, I assume pretty high since the Fountek is quite capable on it's own?

And I'm still not sure if i'm going to add the tweeter or not, or even start the whole project.