60 Degree DIY Mid Hi - AKA PM60

Great work Max ! Looks to be very well braced.
What are the outside dimensions and weight?
And what thickness(es) are you using? ie 15mm / 18mm
I'm figuring the 12" baffle has to be 18mm ??? What's the recess routing?
Any plans to do the 60 degree also?
Thanks, Mark
 
Mark Wilkinson said:
Great work Max ! Looks to be very well braced.
What are the outside dimensions and weight?
And what thickness(es) are you using? ie 15mm / 18mm
I'm figuring the 12" baffle has to be 18mm ??? What's the recess routing?
Any plans to do the 60 degree also?
Thanks, Mark
Click to expand...
Mark,

I totally forgot to include the outside dimensions. I have added those and updated the plot and drawing files. Additionally, I have corrected the error in the pdf file where only one of the seven plates was shown. Most of the answers you are seeking are located in detail drawings, but I'll go point by point anyway:
  • The cabinet is 398x455x935mm. Weight should be similar to other approaches, approximately 80lbs total. I won't know until I build this exact version, but it's essentially on par with other options.
  • This design uses a combination of 15mm and 18mm ply. Essentially, everything is 15mm, with the 12" baffles being the only 18mm pieces.
  • The 12" baffles are indeed 18mm, with a 9mm recess. I have considered making this 10mm or 10.5mm, but I really don't think it will be an issue. Once you high pass the cabinet, the max excursion drops significantly, and I have assumed doesn't reach xmax often before the VC melts. Maybe I'll test that hypothesis with an acrylic panel version someday (probably not, though - too expensive!).
  • The only modification needed to make this box work with the 60 degree horn is a different cutout on the front baffle. The 4594 will still fit, though it will certainly be a tight fit! While not shown in my drawings, this design would also easily support interchangeable horns. I'd probably just add a small outside ring of bracing around the edge of the horn baffle, and use t-nuts or something better to clamp the horn down. Just some ideas.
I really did try and design this version with everyone in mind. I made sure to consider different drivers, horns, handles, pole mounts, feet, connector types, damping options, and even wiring. Heck, though it's not shown, this design would definitely allow you to cut off the back corners or add angle irons in the corners to provide flying options a laPeter Morris's version. Really, I hope these drawings are a good reference for anyone starting this project, whether they go with what's there or customize to their heart's content.

Happy DIY!

UPDATE ON EXCURSION - I did some crude modeling in Hornresp and it claims at 80V the maximum displacement in band would be 9.4mm @86Hz before processing. I probably will increase it to 10.5mm just to be safe in the future.
 
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Wow Max that’s awesome – I never expected when I posted my original pictures of this design there would quarter of a million views and hundreds of pages of posts, or someone producing such a great drawing / plan.

I have had a couple of discussions lately with my friend who is an absolute horn design wizard about designing a HF horn a little bigger than the RCF to fit in this box as well as generating some GLL files … don’t know at this stage, but I’m investigating :)

Regarding the excursion – that’s almost exactly what my modelling predicted, hence the original 10mm spacer and the 100Hz crossover. I would expect under normal full power operation not to exceed the drivers linear travel.
 
Thank you Max, that all sounds really good. Sorry I'm slow to get back...incredibly busy.

Last night, I loaned a pair of DIY90s and some labhorns to a friend doing an outside resort-type bar / restaurant ...several hundred people.
Worked super...a number of folks said it's the best sound the venue ever had. It really stoked the band to play to a higher level, and ended up drawing a larger crowd than expected.

My friend definitely wants to get a pair of 90's -:) Should I point him to you?
 
Helge Dr. Bentsen said:
Peter: What's the acoustic spacing of the 12"?
How high could you raise the crossover before lobing between the 12" drivers becomes an issue in the vertical plane?
Click to expand...
The horn mouth centers are about .7m away from each other.
​
Mark Wilkinson said:
Thank you Max, that all sounds really good. Sorry I'm slow to get back...incredibly busy.
Last night, I loaned a pair of DIY90s and some labhorns to a friend doing an outside resort-type bar / restaurant ...several hundred people.
Worked super...a number of folks said it's the best sound the venue ever had. It really stoked the band to play to a higher level, and ended up drawing a larger crowd than expected.
My friend definitely wants to get a pair of 90's -:) Should I point him to you?
Click to expand...
Mark,
I would be more than willing to help get him a set of DIYs. Feel free to get us in touch!
 
Helge Dr. Bentsen said:
Peter: What's the acoustic spacing of the 12"?
How high could you raise the crossover before lobing between the 12" drivers becomes an issue in the vertical plane?
Click to expand...


There are a couple of issues razing the crossover frequency. As you noted the dipole arrangement means the vertical pattern collapses as as the frequency increases, in this respect I would suggest that 700 – 800 Hz is about as high as you should go. In addition this is a bent horn and its dimensions suggest this is also about as high it should go.

Part of this design is keeping all the diaphragms operating in their piston range. By doing this all the lumps and bumps in the frequency response can be corrected successfully with DSP. A 12” driver's piston range starts to run out at about 800Hz.

From my SIMs very minor vertical lob-ing starts at a crossover frequency of about 500Hz, but it does not become an issue untill the crossover is greater than 800Hz. This of course only occurs through the narrow crossover region.

My pick is 700Hz as a maximum. 600Hz as a minimum for the 60 degree and 650Hz for the 90 degree.

 
Mark Wilkinson said:
Thank you Max, that all sounds really good. Sorry I'm slow to get back...incredibly busy.

Last night, I loaned a pair of DIY90s and some labhorns to a friend doing an outside resort-type bar / restaurant ...several hundred people.
Worked super...a number of folks said it's the best sound the venue ever had. It really stoked the band to play to a higher level, and ended up drawing a larger crowd than expected.

My friend definitely wants to get a pair of 90's -:) Should I point him to you?
Click to expand...

That's really great to hear :)
 
Max Warasila said:
And, many months later...


These are the dropbox links for the current .dwg and .pdf files. I will always keep these public facing ones as updated as possible if I make changes in the future, so check revision numbers and publication dates if you're wondering about a newer version.
https://www.dropbox.com/s/h16is6mbjig6fcy/pm90_current.pdf?dl=0
https://www.dropbox.com/s/xiuyecjy9k6weph/pm90_current.dwg?dl=0
Click to expand...

Hi All,
Just curious if anyone has built a box off of these drawings. I just started cutting wood last night...and already planning on deviating from these. I could see if you had a CNC machine, these would be great, but all the dados and pockets seem quite unnecessary and extreme when building in a garage.
 
Hi David ... I have built some to the plans ... but ...I used simple glue and screw joints. While the relative panel angles remained the same I simplified construction by using a 90 degree cut combine with (for example only) a 80 degree cut instead of two 85 degree cuts.

Cheers
Peter
 
David Sturzenbecher said:
Hi All,
Just curious if anyone has built a box off of these drawings. I just started cutting wood last night...and already planning on deviating from these. I could see if you had a CNC machine, these would be great, but all the dados and pockets seem quite unnecessary and extreme when building in a garage.
Click to expand...

The simplest way to do this is to keep all of the dimensions the same, and just not build the dado joints on the left/right panels. You'll end up with a slightly wider box, but not significantly so. If you want the exact same size, subtract 12mm from the width of each of the internal baffles. The recommended changes for a garage environment that I thought up when designing this were:
  1. Subtract 12mm from the horizontal axis of each of the sandwiched baffles, top, bottom, and back pieces. Per piece notes are:
    1. On the horn baffle, it may be necessary to pay careful attention to the 60 degree horn width, as the T-nuts on the sides may not have sufficient clearance when the baffle is shrunk. It should be fine, but I don't remember checking.
    2. For the main vertical brace, be sure to maintain enough space for the horn and 4594HE to fit through.
    3. For the ported baffles, be sure to keep the 60mm holes slightly away from the walls to prevent a boundary effect that lowers tuning (not the end of the world).
  2. Subtract 12mm from the vertical axis of the sides and back pieces.
  3. For the horn braces, just do what works best for your skill level. They do need to be there, but their exact form is not specified. Peter Morris can comment on changes in horn geometry.
I'm getting this 12mm number from the fact that all pockets/dadoes are 6mm deep. As always, these are just recommendations, and I encourage you to make your cabinet your own. The bracing I've demoed here is just easy to cut from scrap, and can certainly be changed/optimized. I'm a computer engineering student rather than a mechanical engineering student, after all.

Peter Morris said:
Hi David ... I have built some to the plans ... but ...I used simple glue and screw joints. While the relative panel angles remained the same I simplified construction by using a 90 degree cut combine with (for example only) a 80 degree cut instead of two 85 degree cuts.

Cheers
Peter
Click to expand...

This is something I wouldn't recommend doing that kind of change willy nilly, depending on how closely you're following the design. While it will work fine if you're not doing pockets, making the change you're suggesting changes the geometry of the piece and could lead to parts not fitting in pockets.

Happy DIY, all!
 
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Max Warasila said:
This is something I wouldn't recommend doing that kind of change willy nilly, depending on how closely you're following the design. While it will work fine if you're not doing pockets, making the change you're suggesting changes the geometry of the piece and could lead to parts not fitting in pockets.

Happy DIY, all!
Click to expand...

The geometry was not changed ... and no pockets, just glued and screwed butt joints ... :) however on the inside of the box some of the joints are not flush as a result of the angle change.

My line-array build was different, every thing was cut out and pre-drilled on a NC router in accordance with an auto cad plan.
 

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The first way of working (making the angle of the cuts the same at both sides) is not more difficult than what Peter Morris proposes: Start with a piece of ply cut to the width of the cabinet. After cutting the first part, simply flipover the remaining piece of ply and the first cut is already at the right angle. Make the next cut at the right angle and repeat.
 
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That's true Peter, but in my case the tools I had made angles very difficult to cut accurately and maintain the correct timber width if I had an angle on both sides.

Don't get me wrong for a second ... the boys did a great job of the plans and I'm not suggesting what I did was an improvement. Its just what I did to simplify construction for the tools and space I had.
 
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Hi Jaroslav,

It looks good, not quite as smooth as the RCF in the DIY - but the DIY was designed to be used with EQ. This because the cone mass is a little higher, but I think it should work very well. It has slightly more power handling and more Xmax.

Cheers Peter
 
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Hello peter, great design just finished reading through the pm60 and pm90 threads loads of info ,still trying to process .I know the initial design was max spl on a stick to be used one pm 90 per side or 2 pm 60's per side but have u ever considered a trap version to be splayed 4 per side or is there any way i could get the pm 60 to do it by using a narrower horn.
 
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