60 Degree DIY Mid Hi - AKA PM60

Re: 60 Degree DIY Mid Hi

Peter Morris said:
Hi Brandon - The problem is getting the clearance between the compression driver and the speaker frames - its very close. I don't think it will make much difference either way provided you can still get the internal clearance for the drivers.
Click to expand...

Cool. Yea I think I will ditch the spacer and route in clearance for the 12's. This combined with the 18mm baffle pushing the horn just a little further out of the box should allow for plenty of front to back. clearance. By adding a mm or so to the height and depth of the box I can keep the mid horn path the same.

Do you have any more details on the procedure for routing out the clearance for the 12's excusion? How deep and wide and what profile did you use for the router bit?

Thanks.
 
Re: 60 Degree DIY Mid Hi

Brandon Wright said:
Do you have any more details on the procedure for routing out the clearance for the 12's excusion? How deep and wide and what profile did you use for the router bit?
Click to expand...

Brandon,
Post 18 shows how I routered mine. I made it 7mm deep and still used a 5mm spacer to give the proper clearance. Post 20 shows Peter's method. It looks like he may have used a chamfer style bit and left the center section. His way eliminates the need for the spacer and keeps the proper volume at the exit to the horn.

I used a circle cutting guide for my router to make the clearance cut out. Its cut out at a radius of 140mm.
 
Re: 60 Degree DIY Mid Hi

Brandon Wright said:
Cool. Yea I think I will ditch the spacer and route in clearance for the 12's. This combined with the 18mm baffle pushing the horn just a little further out of the box should allow for plenty of front to back. clearance. By adding a mm or so to the height and depth of the box I can keep the mid horn path the same.

Do you have any more details on the procedure for routing out the clearance for the 12's excusion? How deep and wide and what profile did you use for the router bit?

Thanks.
Click to expand...

The clearance issue is both vertical and horizontal - the compression driver sits between the spokes of the 12" frame.
 

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Re: 60 Degree DIY Mid Hi

Don J Davis said:
Brandon,
Post 18 shows how I routered mine. I made it 7mm deep and still used a 5mm spacer to give the proper clearance. Post 20 shows Peter's method. It looks like he may have used a chamfer style bit and left the center section. His way eliminates the need for the spacer and keeps the proper volume at the exit to the horn.

I used a circle cutting guide for my router to make the clearance cut out. Its cut out at a radius of 140mm.
Click to expand...


This is what I used https://www.parts-express.com/jasper-circle-jig-model-200--365-250 to make the recess as below. I used a round bit and made about 5 passes at different diameters and depths to follow the cone profile.
 

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Re: 60 Degree DIY Mid Hi

Don J Davis said:
Mark,
You'll get a lot out of the Smaart class. I took it last year. Jamie Anderson was great.
Here is an older post I found that is a really good lesson on understanding traces. https://soundforums.net/threads/2474-Virtual-SMAART-training-Tell-the-crossover-frequency-and-type
I really have a lot to learn.

For the weight, yes it would be great to lose about 10 lbs. With a step ladder I am able to get the box on the crank stand myself but I'm at the limit of what I'm comfortable with. With 2 people its not too bad. I'm adding the grills and paint this week and will weigh them. I'm guessing they'll come at 77# plus. For comparison, a JBL SRX722 weighs 76#. Down the road I may try and build a lighter pair.
Click to expand...

Hey thx Don,
Yes, looking fwd to Smaart class early July...I'm already trying to envision hoisting speakers up via an open a frame over my deck
Glad your stands are working out !
 
Re: 60 Degree DIY Mid Hi

Brandon Wright said:
Cool. Yea I think I will ditch the spacer and route in clearance for the 12's. This combined with the 18mm baffle pushing the horn just a little further out of the box should allow for plenty of front to back. clearance. By adding a mm or so to the height and depth of the box I can keep the mid horn path the same.

Do you have any more details on the procedure for routing out the clearance for the 12's excusion? How deep and wide and what profile did you use for the router bit?

Thanks.
Click to expand...

Brandon, I tooled up to go the router route, but ended up staying with a 12mm spacer just because i had already made them before the router idea surfaced, and they are a bit of a pain to make...two big circle cuts.

If I make another pair, here's my current plan...

Make a baffle board out of two 12mm sheets of BB that stack together to form a board 24mm thick.
Route out the top one closest to the driver the full 284mm diameter...it effectively becomes a spacers with a bit of extra corner material.
Route out the bottom one for the slot like Don says with a circle guide for ends of slot.
Glue em together.
Least routing I can think of.....good strength...reasonably light. Just another idea...FWIW.
 
Re: 60 Degree DIY Mid Hi

Hey Peter, another one of the endless questions :?~:-?~:???:.....are you using any voltage limiting, rms or peak? Particularly on the coax sections... Thx!
 
Re: 60 Degree DIY Mid Hi

Mark Wilkinson said:
Hey Peter, another one of the endless questions :?~:-?~:???:.....are you using any voltage limiting, rms or peak? Particularly on the coax sections... Thx!
Click to expand...

Yes - the Lake can do some very clever limiting, it has LimiterMax™ peak and RMS limiters, I'm using both.

I'm also looking at making some yokes like these so the boxes can be angled down a little.
 

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Re: 60 Degree DIY Mid Hi

Peter Morris said:
Yes - the Lake can do some very clever limiting, it has LimiterMax™ peak and RMS limiters, I'm using both.

I'm also looking at making some yokes like these so the boxes can be angled down a little.
Click to expand...

Neat! I like how yokes like that maintain a center of gravity of the pole.


Do you think the LimiterMax voltage settings would have any validity copied to a DSP amp (qsc pld) that allows rms and peak settings?
I guess the attack and release would have to match up pretty well too ??

Because I'm going to cry if I inadvertently toast the 4594HE's 8O~8-O~:shock:
 
Re: 60 Degree DIY Mid Hi

Mark Wilkinson said:
Neat! I like how yokes like that maintain a center of gravity of the pole.


Do you think the LimiterMax voltage settings would have any validity copied to a DSP amp (qsc pld) that allows rms and peak settings?
I guess the attack and release would have to match up pretty well too ??

Because I'm going to cry if I inadvertently toast the 4594HE's 8O~8-O~:shock:
Click to expand...

The Lake will do instantaneous attack on the peak setting ... so I don't know how it would translate, but more to the point I'm not really sure where they should be set, perhaps Jack Arnott may have some suggestions ????

What I have done is set the peak and RMS limits conservatively based on BMS specifications - but its just a guess

About 200 watts peak and 50 Watts RMS for the VHF and 400 - 600 watts peak and 100 Watts RMS for the HF

Here is a calculator that may help -

http://www.poulpetersen.dk/Appn/gblimthc.html
 
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Re: 60 Degree DIY Mid Hi

Peter Morris said:
The Lake will do instantaneous attack on the peak setting ... so I don't know how it would translate, but more to the point I'm not really sure where they should be set, perhaps Jack Arnott may have some suggestions ????

What I have done is set the peak and RMS limits conservatively based to BMS specifications - but its just a guess

About 200 watts peak and 50 Watts RMS for the VHF and 400 - 600 watts peak and 100 Watts RMS for the HF

Here is a calculator that may help -

http://www.poulpetersen.dk/Appn/gblimthc.html
Click to expand...

Thx Peter, that's a handy calculator. Yes, I queried Jack a couple of days ago, and will pass on any info if he has any....or better, ask him to post to this thread...
 
Re: 60 Degree DIY Mid Hi

All,

Though I shouldn't be, I am seriously considering building a single DIY mid-high, just so we have one in the DC area, and so I have something to do this summer (in addition to many things). If anything, I'm going to see if I can physically make the box itself - my carpentry skills are not extraordinary. I plan on building mine with maybe a 1/4" extra on the front for a full length grill, just because I like it more. :D~:-D~:grin:

I went ahead and created an excel spreadsheet estimating the cost of the box itself, located here: https://www.dropbox.com/s/p6zaglzy0lsupyy/sf_pm_diymidhigh_priceestimate.xls?dl=0

Please let me know of any corrections to be made (as I've only have a rough idea as a project outsider here) and they will be reflected in the document. With any luck I hope to find myself with a finished box before the year is up!
 
Re: 60 Degree DIY Mid Hi

Helge Dr. Bentsen said:
Have anybody here made a exact model/drawing of the 60 degree? I'm dealing with a cnc-shop for a subwoofer project, I'm considering asking them for a quote for a pair of 60 degrees as well.


Sent from my iPhone
Click to expand...

Helge,
Both Mark and Peter modified the 90 deg box to fit the 60 deg horn (I believe). If I can get a sketch of the modifications they made I'd be happy to update the CAD file and post it.

I built 2 of the 60 deg versions as posted earlier in this thread but had to modify some parts as I built and the cut-off corners ended up being a PITA during the construction. If I had to do it over again I would go with no angled corners.
 
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