New DIY Mid High (90deg) - AKA PM90

Also, are you all cutting the back corners after the box is basically complete (cutting into the 12" baffle and parts C, D & E as well as the back and sides - Meaning: not cutting the 27-30* angle on those panels during assembly)?

Cheers,
Justin
 
Justin Abrahams said:
Also, are you all cutting the back corners after the box is basically complete (cutting into the 12" baffle and parts C, D & E as well as the back and sides - Meaning: not cutting the 27-30* angle on those panels during assembly)?

Cheers,
Justin
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That is how i understand it and that's what i intend to to. It would be nightmarish trying to do it before the bits were assembled and trying to make it all line up perfectly I would imagine.....
 
Justin Abrahams said:
Also, are you all cutting the back corners after the box is basically complete (cutting into the 12" baffle and parts C, D & E as well as the back and sides - Meaning: not cutting the 27-30* angle on those panels during assembly)?

Cheers,
Justin
Click to expand...

That is what I did. I sat that whole box on the table saw, and pushed it through, rotated and pushed it through again. This is why i went went the 45 degree angles.
 
Hi,

I am new on this forum.

Till now we only build horn loaded subwoofers. Double 15" (project stopped after 1 build; was to heavy (105 kg)) and WLX with B&CTBX100. In the future I do like to have great high power top-speakers to combine with 4 WLX subs.

During reading this fantastic DIY project, I was wondering if there are also drawings available for this DIY mid/high speaker with a trapezium shaped box?

cheers from the Netherlands, Jack
 
Jack van Hooij said:
Hi,

I am new on this forum.

Till now we only build horn loaded subwoofers. Double 15" (project stopped after 1 build; was to heavy (105 kg)) and WLX with B&CTBX100. In the future I do like to have great high power top-speakers to combine with 4 WLX subs.

During reading this fantastic DIY project, I was wondering if there are also drawings available for this DIY mid/high speaker with a trapezium shaped box?

cheers from the Netherlands, Jack
Click to expand...

Drawings are here: https://www.dropbox.com/s/h16is6mbjig6fcy/pm90_current.pdf?dl=0

I built a slightly adapted version of the PM90 and it’s in use for a couple of years now. I like mixing on them a lot. :-)

Regards, Peter
... also from the Netherlands...
 
Jack van Hooij said:
Hi,

I am new on this forum.

Till now we only build horn loaded subwoofers. Double 15" (project stopped after 1 build; was to heavy (105 kg)) and WLX with B&CTBX100. In the future I do like to have great high power top-speakers to combine with 4 WLX subs.

During reading this fantastic DIY project, I was wondering if there are also drawings available for this DIY mid/high speaker with a trapezium shaped box?

cheers from the Netherlands, Jack
Click to expand...


If you read through all the pages of posts, the discussion of trapezoidal boxes comes up frequently. Moving to a trap box would put it well overweight for being placed on a standard tripod stand.
 
Thanks for your response @peter... I initially planned to build some DIY MT122s to go along with my 8 TH118 (Xoc1 design), then my fellow sound guy introduced me to your design and said I should go down this road instead... I'm now finished reading the thread and convinced he is right... Just one question, How well does this design(MT122) match up against the pm90?

Regards leon(JEDDi Sounds, Dominica)
 
Hi Leon,

The design concept for the PM60/90 is quite different to the MT122.

The PM90 has a dispersion of 90 x 50 degrees. It is designed to be light weight and pole mountable and cross over to the sub at 100Hz. The design idea was maximum SPL and sound quality on a stick. If size and weight were not an issue I would used a different design.

In comparison the MT122 is much bigger, heavier and has a dispersion of 40 x 25 degrees and does not go as low. As such I expect it will be a little louder, but you will need to cross over some where above 125-150Hz. I suspect it was designed to be used in pairs. When you do a SIM with two MT122’s per side the response looks quite smooth. The MT122 is also a straight horn which should provided better HF performance and allow a higher crossover frequency and the use of "standard" compression drivers.

To push as much performance as possible out of the PM90/60 requires reasonably complex processing and equalisation. The MT122 will be much simpler to process.
 
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I'm really interested in building some of these... Think it will be the best choice for my sound company... I'm only concerned with making it sound as good with just a dbx pa+ or 4800 for processing... I'm new to the whole FIR stuff... And I'm curious to the dispersion, can I stack 2 or more of these per side, and are their plans to make them arrayable... Or can I just stack them above each other horizontally and get the same effect?
 
Yes you can use these processors, but they don’t do FIR filters. Two of the 60 degree boxes work well together side by side with about 40-50... ish degrees between the boxes, but you will need to have separate PEQ settings for depending on the number of boxes you use as there will be some low mid build up. This of course happens when arraying any group of speakers.
 
Peter Morris said:
Yes you can use these processors, but they don’t do FIR filters. Two of the 60 degree boxes work well together side by side with about 40-50... ish degrees between the boxes, but you will need to have separate PEQ settings for depending on the number of boxes you use as there will be some low mid build up. This of course happens when arraying any group of speakers.
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Ok... I was thinking of building the 90 degree version(pm90_current.PDF), can this be arrayed as well? And the seperate PEQ will just be when I'm using multiple cabs? Please excuse my many questions, but i m used to just plugging and playing cabs... I'm new to the DIY mid/high top tunning... Only built subs(th118s)... I just wanna make sure thats I have enough coverage and SPL for the type of live events I do... Peter I'm gonna PM you, what's your email?
 
Generally the idea when you array cabinets is to splay them at their nominal coverage angle. The PM60s have a narrow-ish 60 degree coverage and can be arrayed from about 40 to 60 degrees. I have not tried the PM90 but I suspect you could array them with 75 - 90 degrees between the boxes for a total coverage of 150 - 180 degrees.

You can of course array them with a lesser angle but you will start to cancellation and other issues.

If you need you can send me a PM
 
Peter Morris said:
Generally the idea when you array cabinets is to splay them at their nominal coverage angle. The PM60s have a narrow-ish 60 degree coverage and can be arrayed from about 40 to 60 degrees. I have not tried the PM90 but I suspect you could array them with 75 - 90 degrees between the boxes for a total coverage of 150 - 180 degrees.

You can of course array them with a lesser angle but you will start to cancellation and other issues.

If you need you can send me a PM
Click to expand...
Ok... Messaged you
 
The end is in sight, thanks again for the design Peter and Max for the drawings!

vt121Bv.jpg
 
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That looks great Ti ... and Max and Marks contribution has been fantatsic; not to mention everyone one that was brave enought to build some PM 90/60's. I just hope they are all going as well as mine are :)
 
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