DIY MTM Build - SM16IH-8+TL25SN

[kcnanand]

Looks awesome, I am having the same midbass driver n tweeter,earlier I was planning to build a BS but not it will be MTM speakers like u r built. How is the stereo imagining ?
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Imaging and sound is good. using a diy ta2022 based amp. i have now paired it with a 8 inch sub to give the very low end a boost and the result is very good

 

[amit46]

My first MTM speaker build using the Peerless India SM16IH-8 mid woofer and the TL25SN Tweeter. Wanted to upgrade my earlier TM build to a MTM basically to get more sound out of the box. After some reading on google and suggestions by members decided to go ahead and build one. Ordered up a pair of SM16IH-8.
Various online resources and the winisd optimum calculation resulted in a very large box that would take up a lot of living room space and will also look unwieldy. Also wanted to restrict myself to One sheet of 17mm MDF board that had a width of 1220mm.

After lot of research decided to settle on the following box dimension (external):-
Height - 1220mm, width -220mm depth-340mm
Box volume - 68 Ltr, Fb-41Hz, Vent dia 3 inch, Vent tube length 2.5 inch.
Spent a day to cut up the MDF with circular saw, butjoint the panels, glued and wood screw for tight fit.

Few Pics (uploaded to mediafire and shared as forum embedded)

The front panel 220mm wide. The center of top speaker is 11 inches from the top centered on the panel and the tweeter center is offset by 1/3rd of the center. speakers and tweeter is flush mounted.





Bracing behind the tweeter, above and below the woofers. distance is random but same on both speakers. the bracing is in the shape of a T (cross brace for the width and support brace for the front)


T-nuts for fixing the speakers. the inside edges of the box sealed with silicon sealant.


The box was stuffed with polyfil (about a large pillow worth). The polyfill is only up to 2/3rd of the height of the box. Fixed a cloth mesh to help the polyfill stay in place. Did a test run, removed/added polyfill till i felt that the bass extension was nice and tight.


Once i was happy with the sound, finished the box. The sides are sunmica laminate. Front and back black matte finish vinyl that i got from a car/sticker guy. (perfect thickness and good adhesion)






Simple Crossover is a 3rd order butterworth. crossed at 2500Hz. The woofers are wired in parallel to get 4 ohm. the Lpad is for around 3.44 db attenuation. The design aim was to keep the graph as flat as possible. the values are rounded off to the closest possible. C1 was 14 but could only find a 12uf and 2.2 uf which i wired in parallel. 2x12uf for C3 of 24 uf.


Sound test: I am happy . Much better resolution than my earlier build. nice separation, tight bass. sound seems to be best suited for my listening (vocal heavy songs with deep background bass). I do not have any mechanical measuring devices and relied on my ears and of my friends.
hyeah:

Excellent work...keep it up!