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Old 6th February 2013, 05:17 PM   #141
tb46 is offline tb46  United States
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Location: Texas
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,
Attached Files
File Type: pdf 12PS100_side_dims.pdf (5.2 KB, 17 views)
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Old 6th February 2013, 05:31 PM   #142
Chaps is offline Chaps  Denmark
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Quote:
Originally Posted by ghettosynth View Post
They look great. Do you have any measurements, or even simply comments regarding their performance? Also, if it's not too much trouble, I'd love to know what drivers, handles, and connectors you used as well as any particular issues that you might have had during construction?

I love the stacking feet, I presume that they have been routed so that they can be stacked in either dimension?

I'd love to see more pictures, either build shots, or side/rear shots, if you have them.

At the risk of pushing my luck, have you weighed them?

As I say, they look great, you appear to know what you're doing and it would be great to hear field reports from people who have actually used them. I've seen plenty of discussion about MTH30 builds, and, of course, this thread has a lot of discussion of the THAM12 design, but I've seen very little about actual THAM12 builds.

tnx,
gs
Hi GS.

As i haven't really had the time to play with them (thet finished yesterday) i have no measurements, but i have an initial impression after a few minutes of listening. They sound very clean, punchy and precise. I heard them next to a commercial 2x15" reflex cab (NOVA Visio VS215) and there was a huge difference in sound quality. The THAMs just walked all over the reflex cab with lovely sounding bass.
After this coming weekend i can comment some more on the SPL the THAMs can produce.
I had them crossed at 45Hz with a 24dB BW slope and i think i might raise that to 50Hz in hope of getting rid of some cone movement. All in all i look forward to play around with different settings and i will of course post my findings.

Mine er loaded with PD.12SB30 drivers. All accessories can be found at Adam Hall. The rubber feat is 38x10. The handles is the smallest model they have (can't remember exact size). The pole mount is with 20mm thread. Connectors is standard round 4-pole neutrik.
Construction wise, to fit the handle i just moved the upper brace to the side. The pole mount is just mounted far enough back to not interfear with the internal panels.
All-in-all not anything speciel. BUT if you are to build with PD.12SB30 you have to make the cabinet a few mm. wider to make the driver fit!

You are right. There have been routed for feet on both sides and top/bottom. The way they are on the pic is only intended for transportation, as i want to use them laying on there sides.

Some building pics:

Click the image to open in full size.
Assembly
Click the image to open in full size.
Assembly
Click the image to open in full size.
Almost finished with the first cab
Click the image to open in full size.
After routing of the edges + test mounting of the drivers
Click the image to open in full size.
After 2 layers of paint. They could need some more though
Click the image to open in full size.
Mounting all fittings and drivers
Click the image to open in full size.
Done and quick test

EDIT: Just had them on the bathroom weight. It says 28kg each.

Last edited by Chaps; 6th February 2013 at 05:36 PM.
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Old 6th February 2013, 07:48 PM   #143
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Quote:
Originally Posted by Chaps View Post
Hi GS.

I had them crossed at 45Hz with a 24dB BW slope and i think i might raise that to 50Hz in hope of getting rid of some cone movement. All in all i look forward to play around with different settings and i will of course post my findings.

Mine er loaded with PD.12SB30 drivers. All accessories can be found at Adam Hall. The rubber feat is 38x10. The handles is the smallest model they have (can't remember exact size). The pole mount is with 20mm thread. Connectors is standard round 4-pole neutrik.
Construction wise, to fit the handle i just moved the upper brace to the side. The pole mount is just mounted far enough back to not interfear with the internal panels.

Some building pics:

EDIT: Just had them on the bathroom weight. It says 28kg each.
Thanks so much, for a beginner who doesn't want to either make simple mistakes, or conversely, worry about the wrong things, your post was super helpful.
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Old 6th February 2013, 08:04 PM   #144
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Quote:
Originally Posted by Chaps View Post
I had them crossed at 45Hz with a 24dB BW slope and i think i might raise that to 50Hz in hope of getting rid of some cone movement.
Assuming the Tham 12 simulation is correct, (which you could confirm with sine wave testing) the excursion minima is around 51 Hz.
With a BW24 at 45 Hz the drivers are more likely running out of excursion in the 60-80Hz range, only way to reduce that is turn down the volume.
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File Type: png Tham Excursion.png (55.5 KB, 28 views)
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Old 6th February 2013, 08:17 PM   #145
Chaps is offline Chaps  Denmark
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Can only say that you are absolutely correct according to that simulation.
I will have to do some proper testing to find out how much power they can take without exceeding xmax.
As i am looking at the drivers moving it seems to me, that they sometimes move quiet alot, but is there an easy way to see/measure how much the cone is actually moving?
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Old 6th February 2013, 08:39 PM   #146
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Originally Posted by weltersys View Post
Assuming the Tham 12 simulation is correct, (which you could confirm with sine wave testing) the excursion minima is around 51 Hz.
With a BW24 at 45 Hz the drivers are more likely running out of excursion in the 60-80Hz range, only way to reduce that is turn down the volume.
So in 60-80hz it seems that the graph suggests that the output is less than 0.5mm, is that supposed to be 0.5cm? The driver has an xmax of 7mm so 0.5 cm would make more sense?

Perhaps I misunderstand something else?
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Old 6th February 2013, 08:49 PM   #147
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Quote:
Originally Posted by Chaps View Post
Can only say that you are absolutely correct according to that simulation.
I will have to do some proper testing to find out how much power they can take without exceeding xmax.
As i am looking at the drivers moving it seems to me, that they sometimes move quiet alot, but is there an easy way to see/measure how much the cone is actually moving?
Simply put a white dot on the cone, run sine waves through the cone, and compare the dot's peak to peak movement at various frequencies with a ruler.

When approaching Xmax (half of the peak to peak distance), make sure to not run sine waves for more than a few seconds, and leave at least double the time between tests as the individual tests take.

If you don't want the detail, use pink noise. If you raise the HP to 50 Hz and the cone is still over Xmax, you know the problem area is above Fb.
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Old 6th February 2013, 09:08 PM   #148
Djim is offline Djim  Netherlands
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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.
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Old 6th February 2013, 09:17 PM   #149
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Quote:
Originally Posted by ghettosynth View Post
So in 60-80hz it seems that the graph suggests that the output is less than 0.5mm, is that supposed to be 0.5cm? The driver has an xmax of 7mm so 0.5 cm would make more sense?

Perhaps I misunderstand something else?
It is only driven at 2.83 volts, the figures are in mm, the comma is substituted for a period.
The driver runs out of excursion before the voice coil burns .
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Old 6th February 2013, 10:54 PM   #150
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Originally Posted by weltersys View Post
It is only driven at 2.83 volts
Ok, of course, that's what I missed.
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