3" FR speakers for micro stereo upgrade

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#41
https://www.parts-express.com/Dayton-Audio-PC83-4-3-Full-Range-Poly-Cone-Driver-295-154?quantity=1

i‘ve been using these primarily in project speakers where sound was required ( retail displays, voice control) it’s a nice smooth driver and I’ve gotten useful output to 80hz at low volume….BUT….as Dave pointed out, 3” does not a woofer make so temper your expectation.

Wanna know what I’d do?…..use a 3” high Q driver for the front….divide up the enclosure and use one of the Dayton ND micro subs out the back……that would be a surprise for the listener.
 
#43
tmuikku said:
Hi,
Bass performance can be approximated with simple maths. Lavoce WSF030.70. linked above says cone area is 33cm2 and xmax 3.3mm, which means it can do about 33cm2 * 2 * 0.33cm ~= 20cm3 volume displacement.

If it was on a closed enclosure we can look max output from a chart here , which indicates max output at 100Hz is about 95db, and this is with peaks of course. So calculating some headroom like 15db the speaker could be listened at about 80db at one meter, with driver hitting xmax on peaks at 100Hz.

Tangband W3-871SC above shows xmax of only 0.5mm, which reduces maximum volume displacement to 32cm2 * 2 * 0,05cm ~= 3cm3, which is out of the chart basically. Cutting volume displacement in half reduces output by 6db, so the tangband is quickly calculated roughly 15db down at 100Hz compared to the Lavoce. The lavoce equals about 6 of these TangBands in volume displacement.

Output can be tweaked some using reflex box, utilizing boundary gain, and so on so this is just simplified example how to kind of get into ballpark what one would need to reach some target bandwidth and SPL. Important thing with fullrange drivers is that excursion will really distort the whole bandwidth so depending how the xmax numbers are calculated the sound could get poor before xmax. While fullrange driver speaker can sound really good they are usually limited in max SPL and bandwidth, and simple maths like this can help narrow in to a driver that could meet expectations.
Click to expand...
The poster was specifically looking for a 3 inch driver that would produce good bass in a 1.75L ported box, and the Lavoce is better suited to do that than any other driver proposed. I'd bet .50cents this suggestion models better than the others. There are other drivers this size in the Lavoce line that have much higher sensitivity, but as always with a higher fs and lower x-max. This 10watt portable box isn't going to be used for stereo triangle critical listening, and the biggest issue with a 3" full range in my opinion is getting enough bass out of it for a balanced sound, which often involves rolling the top end off a bit and a bump on the low end so it doesn't sound like a big tweeter, especially when pushed hard. Considering how I think it may be used, and what he was asking for, this suggestion seems to fit the bill as it could produce decent bass in a ported box that small and easily take all the power he has at hand.
However, I also like the CHN-50 very much and really, how much money does one want to throw at a project like this?

Jason
 
#47
Get Alpair 5.3 and made some tests.
Red line as installed in mini stereo, from 1 m.
Green in test box, from 1 m, blue same but gated to 2 ms.
Some correlation with factory measurements is seen.
In mini stereo probably front panel formed wave guide (2 cm deep) have bad influence.

AlpairTests.PNG
 
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#53
kaameelis said:
I have break in Alpair 5.3 for 3 days with 50Hz and little over Xmax amplitude.
Click to expand...

That is not the way they need to break in, that is how you break them… but because there is no spider, the memory of that torture is likely less so it may not have been too bad.

Drivers should be broken in slowly with low level varied material, and slowly increased. Then they keep breaking in as you start actually using them.

I have found that the T/S we measure with the typical diy kit are not nearly as useful as the factory numbers.

dave
 
#54
This way break in takes month or more.
I think measured T/S are close to reality, at least Fs cannot be measured wrongly, Qts and Cms also indicate that Fs must be higher than in factory data. BL is virtually same, it is one number what is not affected by parameters what will change with break in.
 
#56
I decided to built new case for micro, 5 L volume per speaker.
On simulation dotted line with factory T/S, solid with my measured.
I presume breaking in moves speaker T/S close to factory T/S and if needed I can make adjustments with box filling.

Alpair5Sim5L.PNG
 
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