MTH30 Questions : Complete Noob!

[Chaps]

Originally Posted by Djim

Hi Chaps,

When and where did you buy your PD drivers? For accuracy I have to know if you have an old or a new version.

There were purchased from thomann in january. Guess they are the new model.

Art: I may have to try that. Maybe the problem isn't as big as i first thought. I'm just not used to looking at speakers without grills when they get some juice. Well, sounds like a little experiment can confirm whether i'm just overprotective or not

[kornnylike]

Originally Posted by tb46

Hi kornnylike,

For a correct drawing I'll need the shape and depth of the cone. I'll attach a drawing w/ question marks. Also, please verify the overall dimensions in the drawing.

Regards,

Djim and tb46

Sorry for the delay ,I will post the cone dimension measurements later .

[Xoc1]

I decided to unfold the MTH30 to be able to compare the design with the Tham 12

The MTH30 is bigger and the horn is wider but the path is much shorter
S2 to S4 (Or S3) is 157.6cm compared with 172.3 for the Tham 12

The MTH fold is very linear and the only comment I have is the 199MM panel could be increased by 11mm to gain a little path length and linearity.
In its basic form, without any adjustment for the driver, the sim in Hornresp could be done with only 3 sections.
Screen grab of MTH30 unfold, and PDF comparing with the Tham12
Lots of extra dimensions for Akabak fans!
Regards Xoc1

[ghettosynth]

Originally Posted by Xoc1

I decided to unfold the MTH30 to be able to compare the design with the Tham 12

The MTH30 is bigger and the horn is wider but the path is much shorter
S2 to S4 (Or S3) is 157.6cm compared with 172.3 for the Tham 12

The MTH fold is very linear and the only comment I have is the 199MM panel could be increased by 11mm to gain a little path length and linearity.
In its basic form, without any adjustment for the driver, the sim in Hornresp could be done with only 3 sections.
Screen grab of MTH30 unfold, and PDF comparing with the Tham12
Lots of extra dimensions for Akabak fans!
Regards Xoc1

Thanks for the comparison. Can some of you try to connect the differences in the design to expected or measured differences in performance? If we suppose for a moment that either the MTH had a slightly longer path or the THAM a slightly shorter path, what does this mean?

[tb46]

Hi ghettosynth,

How about comparing:

Post #27: Hornresp for MTH30

Post #89: Hornresp for THAM12 ?

Then use the Wizard in Hornresp to see what dimensional change produces what result?

Regards,

[sebDIY]

Bl of PD.12SB30 in post 89 is wrong, It's 19.3 and not 18.3

Sim of MTH-30 (black) and Tham12 (grey), same loudspeaker PD12SB30

[ghettosynth]

Originally Posted by tb46

Hi ghettosynth,

How about comparing:

Post #27: Hornresp for MTH30

Post #89: Hornresp for THAM12 ?

Then use the Wizard in Hornresp to see what dimensional change produces what result?

Regards,

Hi,

I'm sorry if I wasn't clear. Indeed, I've been playing with these designs for some time. Many of these variables are not independent and it is often not clear what in the system is changing when a parameter changes. I was really trying to get a bigger picture here.

[ghettosynth]

Originally Posted by sebDIY

Bl of PD.12SB30 in post 89 is wrong, It's 19.3 and not 18.3

Sim of MTH-30 (black) and Tham12 (grey), same loudspeaker PD12SB30

So, to me, these look similar. The MTH looks like it has a bit more low extension but the roll off of the THAM is less steep, also, given that people observe that the sims are "peakier" than reality, I would expect that the MTH is slightly louder for the same input.

Based on experience, do you guys think that these boxes would produce similar results? Which box would you build? I read elsewhere that they could not be compared because the MTH has much larger volume? I get that the horn length relates to the tuning of the box, but it's still not clear to me how, holding horn length constant, how an increase or decrease in volume will affect the system.

[kornnylike]

Originally Posted by tb46

Hi kornnylike,

For a correct drawing I'll need the shape and depth of the cone. I'll attach a drawing w/ question marks. Also, please verify the overall dimensions in the drawing.

Regards,

One cone dimension measurement coming up

cone dim.jpg

[Brian Steele]

Originally Posted by ghettosynth

Which box would you build? .

I'd go for something in-between . The FR curves suggest that the THAM12 is too small and the MTH30 is too large for the driver you modelled.