MTH30 Questions : Complete Noob!

1) I see that the MTH30 calls for MDF. I would rather use plywood for weight, is this a good idea? If so, does it require changing the plan in any substantial way? Any experiences with plywood vs mdf would be helpful here.

I recommend MDF - it is stiffer, and less likely to resonate. If you use plywood then use the thickest you can, and consider more bracing,and stiffeners.

Keep the internal dimensions the same.

Don't know where you dwell or the conditions but you might to consider using marine grade - less likely to 'fall apart' when the humidity is high.

MDF is heavy! I built a mini-platforms [with casters] for when I had to move my LH transmission line speakers.
 
Tb46
I recheck all the measurements of the b&c 12ps100 cone dimension several times to make sure that they are all correct.:D
Hi kornnylike,

How did you measure the depth from the front to the centre of the dome and the depth from the edge of the dome to the front?

The reason I ask is because TB46's model, based on your measurements seems odd. When I checked my own drawing it looks like you measured the depth from the edge of the cone (where the cone ends and the surround begins) instead of using the real front See picture;

B%2526C_12PS100_drawing_06.jpg
 
Hi Djim and kornnylike,

What is the dimension from the mounting edge of the speaker to the triple roll surround (tip of the rolls and approximate center)? That still looks a little deep based on kornnylike's data in Post #159 (15/32" - 0.46875" [11.9mm]).

Regards,
 
I recommend MDF - it is stiffer, and less likely to resonate. If you use plywood then use the thickest you can, and consider more bracing,and stiffeners.

Keep the internal dimensions the same.

Don't know where you dwell or the conditions but you might to consider using marine grade - less likely to 'fall apart' when the humidity is high.

MDF is heavy! I built a mini-platforms [with casters] for when I had to move my LH transmission line speakers.

Plywood is both stiffer and lighter than mdf, but not as damp, ply is by far the prefered sub and pa material. 5 ply is stiffer and cheaper than many-ply baltic, but can have voids. I recently built with half inch ply with great results, braced properly.
 
I don't see why you can't use a THAM or MTH fold for a TH with the same throat, mouth, and horn length dimensions.
You cannot use corner reflector on the mouth of the THAM fold to get the same performance as the MTH.
Personally, I prefer the multiple mouth exit options of the MTH.

T-TQWT.jpg