3" FR speakers for micro stereo upgrade

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kaameelis

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Joined 2004
#1
I get second hand all in one box micro stereo with 3" speakers and sound of it really needs upgrade.

I made measurements in room from 1m and there are problems to solve. Room modes have very little influence and holes on 500 Hz and 1.2kHz are from speaker.
Black line is bass reflex port near filed and blue is speaker near filed measurement.
Port+box have very low Q, probably because air leaks, this can be easily fixed, but can help only increase very little in bass response.

MicroStereMes.png


My first idea was Alpair 5.3.
Speaker box volumes are 1,75 L what is very little but it cannot be increased.
Simulation of Alpair 5 in existing box with existing port ( 30 mm diameter, 80 mm length) give not best results, solid lines on image
Optimized volume configuration lines are doted, 3,58 L box, port 30 mm diameter, 80 mm length.

What other 3" FR speakers can be used with small bass reflex box volume?

Alpair5.PNG


If I increase port length in simulation to 140 mm change is to better but little.
Alpair5increasedport.PNG
 
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#2
My 3 goto 3” FRs are the A5.2/3. FF85wk, and CHN-50

Optimal miniOnken volume is 2.5 litre but i have squeezed them into as small as 1.5 litre. Thr Fostex probably the happiest in that small volume.

Given the bump you will have at the bototm a venty with some resistance to knock that down at least a bit.

Can you fit the big bezel Alpai rin your tiny box?

dave
 
#5
Fostex FF85WK have only 0.35mm Xmax, can it handle any bass?
Vas is smaller than Alpair 5.3 have, but Fs higher so result in bass region is about same.
Little bit same about CHN-50, it have smaller Vas but higher Fs.
3FE22, smaller Vas but higher Fs.
As generally on bass region only cone area matters.

Probably also only 4 ohm speakers are suitable. Original is 4 ohms and amplifier power with it is listed as 10W, so on 8 ohms power can be too low.

Witch of them have best mid and high range?
Actually I did not find any polar plots about Alpair 5.3 and CHN-50.

Probably I can fit Alpair 5.3 as front panel have under the grill some waveguide type of plastic cone what can be cut.
On original port end is glued some resistance from net fabric.
 
#6
kaameelis said:
Fostex FF85WK have only 0.35mm Xmax, can it handle any bass?
Click to expand...

No 3” can really do bass. In this small a box i suspect the Fostex will be better, both fit with the volume and likely the fit to the box.

Fostex xMax is usually small, xPeak large. And given there is no specification for xMax it becomes hard to compare brands.

dave
 
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#10
mashaffer said:
I don't quite understand why a speaker system with such a small driver is designed as a BR. It seems that almost all real bass we be where the driver is unloaded. Seems like that would be pretty hard on the driver.
Click to expand...
The right 3.5" in a MLTL will have the knee at about 55Hz. It's believable bass, and some meat, but of course, not at electronica or movie levels.
Still, for a lot of music and a small room, it is enough for many people.
 
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#20
Very nice. Those drivers look fine. Fill those spaces with fiberglass, dacron or acoustic foam and measure again. Place the microphone close to the driver to see just the response of the driver without the baffle diffraction, floor bounce etc. That will show just the driver and cabinet resonances in the measurement. An impedance sweep can help find resonances as well. Use Arta / Limp free software and 100 ohm resistor with your sound input/output to make impedance measurements. If you still wanted to replace that driver, this one from SB looks interesting. Xmax 4.5 mm for good bass and a pretty flat response. https://www.madisoundspeakerstore.com/approx-3-fullrange/sb-acoustics-sb10pgc21-4-3-full-range/
 
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