Restored Sunn 415M Cabinet

[Jeff Troy]

Hi Guys,

Very productive day. I figured out my materials list for my four homebrew Sunn floor monitors (one 12" and one tweeter in each), cleaned and dressed my two 412SR cabinets, prepared the Model 6 cabinets for new corners and accessories, organized all the hardware and fasteners for polishing, and managed to get the photos and take the measurements LB and DM need for their 415M cabinet projects.

I'm tied up all evening and all day tomorrow, but will try to post images and dimension tomorrow evening, Sunday at the latest.

I was able to measure almost everything accurately, although there are a few spots where there is no practical access, so a builder will need to cut and fit. Naturally, I'd STRONGLY suggest cutting and fitting each part as construction progresses. I'm not drawing factory blueprints or CAD files, I'm older than I should be, and my sh*t could be slightly off.

More tomorrow.

Warmest...

[D(o)))(((o)M]

thanks man keep me posted

[Jeff Troy]

Hi, DM,

On my way to a car show with my plastic racer and we're having a cookout afterward.

I can do the drawings and upload images this evening, probably sometime after 10PM Eastern by the time it posts.

Sorry for the delay, but fun is always first.

Warmest...

[Jeff Troy]

Hi, DM and LB,

Long day Sunday and a funeral yesterday. Had the shots, but no time to draw.

Just finished the drawings, approximately 1/4-inch to the inch in not-so-exact scale.

The side wall and baffle construction drawing on the second page is actual size.

I could not get access to measure the depth of the vertical gussets behind the baffles, but please see that they are V-grooved to receive the baffles.

The left baffle is 17.75 inches wide and the right baffle is 17 inches. The rear edge of the right baffle is glued against the face of the left baffle at the rear.

Also note that there are 0.75-inch triangular doubler gussets on the cabinet floor and ceiling ahead of the baffles, as well as full-length 0.75-inch square runners behind the fronts of the baffles on both sides of the cabinet.

I'll post images later today (after burial service), and images should explain most everything else. If not, I'll try to answer any questions.









Images later.

Warmest regards...

[Jeff Troy]

Hi, Again,

Here are the images. With my notes, the images should be self-explanatory.

Here's the 3-quarter front view in the garage.


Tight front view shows grille mounting blocks and baffles.
All eight corners have 3-point nickel-plated corners. You can get these from Conrad.


Handles on left side are centered 4 inches from the top and 4 inches from the bottom.


Rubber feet (from Conrad) on right side are centered 2 inches in and down from each corner.


All sides have 3/4-inch doublers that are 1-1/2 inches wide.
This makes the wood under the Tolex appear to be 1-1/2 inches wide.
1-inch by 1-1/2-inch rails are behind the doublers. Grille mounting blocks are attached to the rails.
Baffles snug against the rails, and 3/4-inch-square supports run full-length, top-to-bottom, behind the baffles.


The floor has a triangular gusset running from side to side in front of the baffles.


Another triangular gusset is at the top. Grille mounting blocks are centered at the top and bottom.


Detail of a typical side grille mounting block, each of which is 1 by 1-1/2 by 1-1/2 inches


Here's the grille block at the top.


Another grille block at the bottom. The nylon hook & loop parts can be replaced with
Industrial Strength VELCRO brand hook & loop material from the craft store.


Center triangle gusset is 12-1/2 inches wide, and cut to fit the angle of the left and right baffles.


The grille (from Conrad) is mounted on the frame, followed by the Sunn logo plate.
For other projects, I scanned the logo plate, then removed the registration mark and had my
graphics guy duplicate the logo in black vinyl. I cut aluminum plates to size, then drilled them
and used a countersink to fit the #4 x 1/2-inch Phillips-head wood screws. I applied the vinyl over the plates,
then used #600 wet-or-dry on a rubber block to get the appropriate semi-satin finish.
I'll show you the results when I post a few of my other pieces. I removed the registration marks because I don't
want to mislead anyone. I just enjoy keeping the appearance of my equipment pseudo-correct.


Here's the grille frame from the rear. All corners should be rounded.
Be sure the leave extra wood at the top left corner for the logo plate.


In keeping with fooling only myself, I hit the centers of my Eminence speakers with a light coat of
silver spray. Cheesy, yes, but it makes me feel good and looks correct when the grille is mounted.


Here's the ID tag on the cabinet back.


Warmest regards,

Warmest...

[chev]

wow that cab is huge! amazing! i love it.

[D(o)))(((o)M]

not really that big 26 wide by 40 high by 18" deep is pretty darn close to the size of a 2x15 cabinet, but the sound is huge yes definitely!! so i start my build on monday and i'll post pics and such.  I'm making some mods to the original design to make the cabinet road-worthy.  mainly huge scoop(marshall-style) handles on the sides and mine will be running at 2ohms.  i'm gonna have to wait for supplies (i.e. grill cloth,tolex, corners etc...) but the wood shell will be finished by the end of the week jeff troy you rule my friend.  those drawings are just what i needed ... i made a cut list that i'll also post so if anybody else wants to build one of these beasts it will even be more simplified.  i just cant wait to get started!!!

[rot gut]

thanks for the blueprint, i'm probably gonna make one when i have some spare cash and time.

how are the baffles held in place?

[stanner]

any sound structure theory guys on here? i would like to know about the efficiency of those V shaped baffles.
having speakers facing semi towards each other would seem to limit output.
am i wrong here?
(i have two sunn 4X15s and just wondering)

[ROCKETBRO2]

The coverage is sure good. I played at a club with low ceilings one time and set it on it's side on an elevated platform on the stage and I think that was the best it ever sounded.

[Where's Uranus?]

Hey Jeff,
             Thanks for the diagrams. You know you can buy aluminum dustcaps, if you really want to go for the authentic look. Sound Speaker Repair sell them as replacement parts for JBL, though I should mention the original Sunn drivers (or bass transducers as the label says) were not vented through the pole-piece but vented through the dustcap, or at least mine are, I've been having a devil of a time finding a replacement dustcap. Weber say they have a 3" vented aluminum dustcap, that they make in house.



Yep I currently have my spare Sunn drivers doing home hi-fi duty.

Might I be permitted the observation that yours is the only 415 I have seen that does not have a port at the bottom? Has the baffle been replaced at some point or were there two types of 415 made, ported and unported? Does it suffer from undue vibration, with the speakers in a sealed cabinet?

[Jeff Troy]

Hi, LB,

Really don't know the answers to your questions. I bought the cabinet used with no speakers, and am only now installing speakers.

I've never played through the cabinet so I don't yet know about vibration.

The cab appears unmodified, so if other 415M cabs are ported, there must have been two models.

Wish I could be more concise for you, but I'm in the dark right now.

Warmest...

[Where's Uranus?]

Hey Jeff,
            Don't worry about it, I was curious more than anything else. If you look at CLD's picture, you can see the port is really what looks like a triangular support, with holes cut in the baffle under it. So far the 415M's I have seen for sale in recent times all appear to have this port configuration

Mine isn't so much a build as a tribute, I'm repurposing an old Peavey 2x15 cab ripping out the baffle and putting in a triangular one to house four speakers. This gets round the wifes 'no more speakers in the house' rule, as it won't be another cab. It's not quite as deep as the Sunn cab, so I'm going to have to fudge it a little I think. All that information on how the baffles are mounted is awesome though. I'd have thought they just bolted it straight to the cab, but they've left it almost floating. Less angle cuts to make I suppose, just need to groove the back support, the rest is all straight cuts.

[HRobert]

any sound structure theory guys on here? i would like to know about the efficiency of those V shaped baffles.
having speakers facing semi towards each other would seem to limit output.
am i wrong here?
(i have two sunn 4X15s and just wondering)

Stanner.  The "V" shapped baffles act as a "horn loaded" system.  With the speakers facing each other at that angle actually causes the sound waves to reinforce each other so as to strengthen the sound.