Tenghong (Aliexpress) 3.5" glass fiber

jr@mac

So, pulled the trigger on a pair of these in an attempt to find something that is easier to play with in the Maggies. Maggies currently use the 3.5" MCM KB full range, and while it is true it is a very low distortion driver it is problematic in the midrange. Not sure it is overly audible, but it bothers me so that counts for something. The Dayton PS95 (I think that is the model, the little FR with the copper colored plug) exhibits almost identical linear distortion, incidentally. 

Anyways, these showed up in an Aliexpress search:





So they use a cute little six spoke frame with no venting to speak of. They have some pretty good mechanical throw, but I have no idea what Xmax is. Otherwise, a very nice looking driver. The mismatch in weave between dust cap and cone is somewhat irritating, but oh well. 

Truth be told, I was expecting garbage - the impedance sweep indicates some level of QC at whatever anonymous factory these are produced in, however.

Sample 1

Loudspeaker parameters:

Fs  = 87.04 Hz

Re  = 7.15 ohms[dc]

Le  = 138.58 uH

L2  = 225.79 uH

R2  = 8.97 ohms

Qt  = 0.75

Qes = 0.90

Qms = 4.54

Mms = 2.89 grams

Rms = 0.348713 kg/s

Cms = 0.001156 m/N

Vas = 1.30 liters

Sd= 28.27 cm^2

Bl  = 3.554444 Tm

ETA = 0.09 %

Lp(2.83V/1m) = 82.23 dB

Added Mass Method:

Added mass = 10.00 grams

Diameter= 6.00 cm

Sample 2

Loudspeaker parameters:

Fs  = 88.63 Hz

Re  = 7.12 ohms[dc]

Le  = 143.47 uH

L2  = 229.96 uH

R2  = 8.68 ohms

Qt  = 0.81

Qes = 0.95

Qms = 5.42

Mms = 2.75 grams

Rms = 0.283216 kg/s

Cms = 0.001171 m/N

Vas = 1.31 liters

Sd= 28.27 cm^2

Bl  = 3.397448 Tm

ETA = 0.09 %

Lp(2.83V/1m) = 82.29 dB

Added Mass Method:

Added mass = 10.00 grams

Diameter= 6.00 cm

They are tight to each other, like world class tight to each other. 



Looks like a significant break up above ~6K, and maybe some errata around 2.4K and a hint of a wrinkle at 1.3K, tho those latter two are likely not of much magnitude - time will tell. 

Visually, these are appealing - and one nice detail I noticed was the dustcaps are oriented the same between both drivers. Woven fabric cones like these have an obvious pattern and throw the light a specific way. The two drivers have almost identical orientation on the dust caps. That just makes me happy. 

On the downside, I was hoping for a sensitivity boost over the MCM, but that ain't happening, yo.

Wolf

I'll bet the different weaves help the breakup. Look nice!

jr@mac

After further inspection, I think it may be a textured poly cone with the glass fiber dustcap. They are pretty nice looking. I may buy the 4 ohm variant to get the sensitivity up a few db - but will get these measured first. 

rjj45

I dropped some coin on AliExpress 4 inch "ceramic" mid-woofers about a year ago. Measured pretty good, and I still might use them in a build. The frame is almost identical to these.

jr@mac

So Craig's soundbar project got me thinking... I have a plethora of small drivers, and maybe a sound bar wouldn't be too bad of a project. 

In 4L tuned to 60Hz, these have an F3 of 49Hz. While obviously not going to win any SPL awards due to the small radiating surface, they should nevertheless provide some very solid wide range sound for moderate listening levels.

Add a small tweeter, and voila. 

rjj45

cute litter buggers!

Kornbread

 I agree, they kill it in the looks department.