60 Degree DIY Mid Hi - AKA PM60

Re: 60 Degree DIY Mid Hi

I finally got around to building some subs to match the DIY Mid Hi.

2 x 21SW152 - 190L per driver tune to about 33Hz.

First impressions ... sounds great, tight punchy, goes low. About 1 dB less efficient than my double 18" subs but despite that it seems to have more authority to the sound (for want of a better description) At full power it should be about the same as 1.5 x my double 18 ( 2 x 18sound 18NLW9000s 275L @ 34Hz).

Excuse the cat, he has been all over this project. Still trying to cut the glue out of his fur.
 

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Re: 60 Degree DIY Mid Hi

Peter Morris said:
I finally got around to building some subs to match the DIY Mid Hi.

2 x 21SW152 - 190L per driver tune to about 33Hz.

First impressions ... sounds great, tight punchy, goes low. About 1 dB less efficient than my double 18" subs but despite that it seems to have more authority to the sound (for want of a better description) At full power it should be about the same as 1.5 x my double 18 ( 2 x 18sound 18NLW9000s 275L @ 34Hz).

Excuse the cat, he has been all over this project. Still trying to cut the glue out of his fur.
Click to expand...

Beautiful, is this the same design that I banged out in Sketchup a few months back?

I've been a bit busy the last few months and fell behind on this project. Is there a final drawing for the 60 degree version of this cab? I know Max was working on putting together a nice drawing...
 
Re: 60 Degree DIY Mid Hi

Spenser Hamilton said:
Beautiful, is this the same design that I banged out in Sketchup a few months back?

I've been a bit busy the last few months and fell behind on this project. Is there a final drawing for the 60 degree version of this cab? I know Max was working on putting together a nice drawing...
Click to expand...

Exactly the same design :)~:-)~:smile:. I couldn't find your Sketchup picture; I wanted to link to it with my post (?).

One of the ideas with this design was to use corner ports to make the box stiff and strong without needing much additional bracing. This would hopefully keep weight down to an acceptable level ... its seems to have worked. Its not as good from a fluid dynamic point of view, but weight was more important to me than port efficiency in this case.

Not sure where Max got to with a final design / drawing but I'm getting some spectacular results with my boxes. They sound better and go louder than anything else I found of a similar size or weight.
 
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Re: 60 Degree DIY Mid Hi

Hi Peter. The 21s look nice, well done. Is it your plan to use a single double 21 per pair of DIY's or a pair? How well matched is a pair of them to a pair of DIY's?
 
Re: 60 Degree DIY Mid Hi

Jim dee said:
Hi Peter. The 21s look nice, well done. Is it your plan to use a single double 21 per pair of DIY's or a pair? How well matched is a pair of them to a pair of DIY's?
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The plan is one Double 21" per DIY mid-high. A single DIY Mid-Hi will easily out run the best double 18. If your music is bass heavy you need two double 18"s per DIY.

Here is the double 21" and double 18" and the DIY double 12 and double 10 on top. The double 18 and double 21 are the same height and depth; the double 21 is just wider.
 

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Re: 60 Degree DIY Mid Hi

Peter, is your material 48"x96"?
Didn't think of this till you posted these pics. Were the top boxes built/designed with materials in mind?
I don't remember paying attention to this detail along the way.
 
Re: 60 Degree DIY Mid Hi

Peter Morris said:
One of the ideas with this design was to use corner ports to make the box stiff and strong without needing much additional bracing. This would hopefully keep weight down to an acceptable level ... its seems to have worked. Its not as good from a fluid dynamic point of view, but weight was more important to me than port efficiency in this case.

.
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The system I built back in '97 or '98 used the exact same idea. Triangular ports surrounding the woofers.

My main concern was to use the ports as support for the walls.

It works VERY WELL, and makes for a very strong cabinet :)

At the time the system used a "low cabinet" and a top cabinet. The low cabinet contained a single 18" sub and 2x15" woofers. Each in its own chamber-vertically stacked.
 
Re: 60 Degree DIY Mid Hi

Jack Arnott said:
Peter, is your material 48"x96"?
Didn't think of this till you posted these pics. Were the top boxes built/designed with materials in mind?
I don't remember paying attention to this detail along the way.
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The double 18 was designed about 17 years ago with materials in mind. At that time ply wood was 48" x 96". In Australia its now metric, 1200 x 2400, slightly smaller. The double 21 was designed to match the double 18.

The top boxes were designed to put as much power and quality as I could on a stick, as such efficient use of material was not really a consideration.
 
Re: 60 Degree DIY Mid Hi

Jim dee said:
How'd the double twenty one come out weight wise Peter?
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Not sure what the weight is, I don't really have any way to measure it but its heavy. It has 4 wheels on the back, I can flip it up by myself so I'm happy with the result. A lot of the weight is in the divers. They are Neo but weight 40 lbs each!

The issue is getting the DIYs on top of the sub / speaker pole. I will post a picture of my solution when I have a little more time (below).
 

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Re: 60 Degree DIY Mid Hi

What PLY did you use Peter?

I think 18mm Hoop Pine sheets were about 76lbs per sheet and Marine Ply 18mm was 84lbs. I looked at this years ago but pretty sure these were the weights. I always use Marine Ply because it has zero voids and was the cheapest. BUT with Marine going up in price I will be using regular ply again but have to buy 10sheets at a time to get a budget cost out of it.
 
Re: 60 Degree DIY Mid Hi

David Chrapla said:
What PLY did you use Peter?

I think 18mm Hoop Pine sheets were about 76lbs per sheet and Marine Ply 18mm was 84lbs. I looked at this years ago but pretty sure these were the weights. I always use Marine Ply because it has zero voids and was the cheapest. BUT with Marine going up in price I will be using regular ply again but have to buy 10sheets at a time to get a budget cost out of it.
Click to expand...

18mm Hoop Pine.
 
Re: 60 Degree DIY Mid Hi

Peter Morris said:
Not sure where Max got to with a final design / drawing but I'm getting some spectacular results with my boxes. They sound better and go louder than anything else I found of a similar size or weight.
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Funny you mention this - I'm trying to finally get a working box done this week. I tried a while back and ended up with a lopsided failure due to all sorts of errors, but I'm feeling much more confident this time!

The hard part was not, by any means, the design of the box itself. I didn't cut the back corners and I didn't include a side panel. I did include a removable front horn baffle and a clever sort of grill to keep things interesting and utilitarian.

What was incredibly difficult, however, was learning and figuring out how to make the design of the box. The reality is that it's nearly impossible to CNC route angles, and to do so is expensive and more time consuming than simply cutting the parts out on a good quality table saw (which I highly recommend). The sides, top, and bottom of the box have CNC routed pockets, the 12" baffle is routed out more or less as called for in the modified, "no ring," design, the horn brace is routed, and the ports, mid-baffle pocket, and half-lap are done on the CNC router for ease. Surprisingly, I don't have access to a table route, so I've sanded the rounded baffle down instead of just using a round-over bit. Go figure.

If you wish to bother me about drawings, I can most certainly draw and get my version to you. The issue with the version I have right now is that it's in Inventor. Great tool - doesn't play well with ANYTHING!!! The other drawings I have are just primitives for use in my CAM software. So I'll just re-draft in CAD eventually. The more you bug me, the better chance that I will get it done before spring break. If you give me an earlier deadline, I'll get it done. Otherwise, it'll get put off, if I'm honest. Up to you all.

One question for you, Peter, though - how did you make the horn curve? It's admittedly the main thing I don't have a great idea for, besides routing out a ton of little curve and piling them up on top of one another!
 
Re: 60 Degree DIY Mid Hi

Max Warasila said:
The one with the larger radius that appears to be made from bent sheathing.
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Found some 8" diameter PVC, thin wall 1/8".
Split it lengthwise into quarters. Dadoed 1/8" recesses into back and top/bottom panels for smooth fit. Expanding foam behind.
Pretty easy...worked great.
 
Re: 60 Degree DIY Mid Hi

Peter Morris said:
Not sure what the weight is, I don't really have any way to measure it but its heavy. It has 4 wheels on the back, I can flip it up by myself so I'm happy with the result. A lot of the weight is in the divers. They are Neo but weight 40 lbs each!

The issue is getting the DIYs on top of the sub / speaker pole. I will post a picture of my solution when I have a little more time (below).
Click to expand...

Step stool?
 
Re: 60 Degree DIY Mid Hi

Max Warasila said:
The one with the larger radius that appears to be made from bent sheathing.
Click to expand...

That's just some thin ply - I soaked it in some water, (its better if you use steam) glued it and forced it into position with some screws. I also put some expanding foam behind it.

I don't think its that important but corner must be filled in to approximate the curve.
 
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