New Stage Monitors Finished

[johnaec]

I took it upon myself to build some new stage monitors for my part-time band, seeing as I had the components on hand. I designed them to be similar in size to JBL's JRX112M, but with a 12" 2206H LF, 2426J HF driver, and PT waveguide horn, instead of the MI components JBL uses. The crossovers are of Zilch Design and construction.

I cut out all the parts for four of them, but so far, have only completed the first two. I'll post a few pics and descriptions in a few messages here.

The first pic shows the main panel parts, (most joints dado'd or rabbeted, with 30 degree butt joints on the back), and the second shows the special 30 degree braces needed for the back sides. The 3rd and 4th pics show how I used jigs for routing the holes required, and the 5th pic shows how the router guide sits in the router. This guide just follows the insides of the jigs around, and is much faster than setting up the Jasper guide for each hole. Any more holes, and I already have the jigs now :) :

[johnaec]

The first pic here shows the inside front of a cabinet, with 45 degree chamfer added for strength. You can also see where the 30 degree butt joints are for the backs. The 2nd pic shows a view to the inside, showing the braces that strengthen the butt joints. The 3rd pic shows an initial test assembly, and the 4th is one of the crossovers Zilch designed and built:

[johnaec]

Here are shots of a final version. First is a head-on view, and 2nd is a view from the side, showing the layout and handle. 3rd is a connector, with two Neutrik and Two 1/4" connectors, all wired in parallel, (for daisy-chaining). The 4th pic is a closeup of the rolled-on DuraTex finish, (thanks for the earlier messages here detailng this source!). It's the same stuff JBL sprays on, under their name of DuraFlex, and is really incredible stuff, and easy to work with! And the last pic is of a curve Zilch ran for me after completion. Red is measured directly on-axis with the horn, and black is on-axis with the center of the cabinet. We may do some more crossover tweaking later, but for now, they really sound excellent!

I'd love to have the lightweight SRX712 monitors like Bo uses, but these only cost me less than a 3rd what SRX712's go for, even on sale! These do come in at almost 50 lbs. each, but really aren't a problem moving with the handle.

All in all, a fun project with good results. And thank! Zilch, for the help with the crossovers!

John

[grumpy]

Nice work! Cool to see this start to finish in Reader's Digest form :applaud:

-grumpy

[toddalin]

Very Nice! Love the texture. :applaud:

[OldBlindJim]

Good Job:D

[Earl K]

Great Stuff John ! ( & Zilch )

[John]

Sweet:applaud:

[Robh3606]

Nice:applaud:

Rob:)

[grumpy]

BTW, if you ever abuse the Jasper Model 200 to the point of ruining the
-two- counterbored mounting holes (at least for Hitachi M12V), don't throw
it away...

There's room to drill/countersink four holes that match the normal foot/plate
mounting. I took care to accurately match drill and found the self-centering
action of the countersunk holes simplified setup, while the four holes on the
perimeter made the jig feel more stable and very unlikely to shift. -grumpy

[Ian Mackenzie]

Nice work John.

Ian

[timc]

Very nice work.


-Tim

[macaroonie]

With a good ending. They look super.:)

[richluvsound]

Looking Good .

:applaud:

Rich

[johnaec]

Thanks for all the comments, guys! Hopefully, I'll get to the second pair before long...

John

[Earl K]

Hi John,

I like the metal screen with it's integrated surround .

Where did you find that ( or is that a JRX part )?


Thanks <> Earl

ps: Do you ( or anyone else for that matter ) have any idea if this water-based DuraTex will properly adhere to an already exisitng coating of oil-based Polyurethane ?

[johnaec]

I like the metal screen with it's integrated surround .

Where did you find that ( or is that a JRX part )? Yep it's a standard JRX grille. Cheaper than trying to fabricate something similar...


ps: Do you ( or anyone else for that matter ) have any idea if this water-based DuraTex will properly adhere to an already exisitng coating of oil-based Polyurethane ?'Not sure, though I'm guessing it would work if the polyurethane was roughed up first, (possibly not necessary). It appears to be highly adherent, and though water soluable, definitely not as much so as latex. Maybe give them a call: DuraTex by Acry-Tech (http://http://www.acrytech.com/store.asp?pid=14119)

BTW - even though I ordered the textured roller from them, I didn't use it. Once a coat was tacky, (less than a minute), I just lightly passed the roller over again, (without more DuraTex), which lifts it slightly, them it smooths down a little as it dries. JBL sprays their finishes on, and really heavily, resulting in a more pronounced texture than mine. I'll have to experiment with the textured roller sometime...

John

[Don C]

The monitors look great. Keep us updated regarding any future gigs. I enjoyed that last one.

[boputnam]

...the last pic is of a curve Zilch ran for me after completion. Those look dandy, John - that DuraFlex finish is nice.
Great size, aren't they!! :yes:

What does the FR look like below 300Hz...?

What is the crossover point?

[johnaec]

That curve doesn't show below 300 because we were doing some tests to determine the results of grille on/off on high frequency response for a thread over at PSW and were ignoring stuff below 300, (because of room nodes, etc.). But they're basically pretty good to around 80-100 hz, maybe a little lower... (we did do some full response curves at some stage, but I don't have those here).

Crossover is at 1.2 Khz. Zilch has already suggested tweaking the crossovers more during assembly of the second pair...

John

[Mike Caldwell]

Great job!
If you want to lighten the load you can replace the 2206's with JBL 2262 neo 12's. There the same one used in the JBL SRX712 and the Vertec 4888 cabinets. I built 8 monitors similar to yours and about two years ago replaced the 2206's with the 2262's and my back can tell the difference! I also used the 2426 driver, a couple have 2425's in them. The horns are B&C ME45. They are all bi-amped. To add more fun cutting the pieces of wood out I made them dual angle. I have some pictures posted in the photo section of the system.

Mike Caldwell

[johnaec]

If you want to lighten the load you can replace the 2206's with JBL 2262 neo 12's.Yea, but at ~$400 each for the 2262, it would have totally negated the whole rationale for building these - cost savings with components on hand. ;) If I could have swung 2262's, I would have just sold my existing components and sprung for used SRX712's instead... :o:

John

[boputnam]

I (should) have just sold my existing components and sprung for used SRX712's instead... :o: :applaud: I was thinking that just last night rehearsing with my SRX712M's. They are dandy.

But seriously, John, your wedges are beauty. You will get enormous satisfaction from using these.

btw - that is exactly the compliment of transducers in the JBL 4825A and 4828A Concert Series monitor/floor wedge, respectively. These use the bi-radial horn, which I cannot imagine is a a good idea on a stage wedge - the horizontal dispersion is far too wide. :dont-know

[Mike Caldwell]

:applaud:
btw - that is exactly the compliment of transducers in the JBL 4825A and 4828A Concert Series monitor/floor wedge, respectively. These use the bi-radial horn, which I cannot imagine is a a good idea on a stage wedge - the horizontal dispersion is far too wide. :dont-know

I never heard the Concert Series monitors but I always thought the same thing about the horn!

Johns' wedges look great and will smoke any JRX model since there loaded with real JBL components!

Mike Caldwell

[Mr. Widget]

Very nice looking John!

Congratulations on a job well done.


Widget

[UreiCollector]

Very nice work, and the DuraTex finish looks great!

[4343]

Nice! I might have put a pole socket on one end for use as the occasional mains, but thats just me thinking like a rental house...
Seriosly, great sounding wedges make good mains for smaller gigs, I've even used a pair as recording monitors in a pinch.

[speakerdave]

Nice, Big John!

[johnaec]

Nice! I might have put a pole socket on one end for use as the occasional mains...Actually, I'm doing just that. It took me a while to find the ones I need, because they couldn't be deeper than 3-1/8", (to clear the LF), and I wanted them metal, not plastic. They arrived a few days ago, and will be installed.

John

[vettedrummer]

Very nice work! What type of music do you play?

[johnaec]

What type of music do you play?Mostly Rock 'n Roll and Rhythm 'n Blues - the kind of stuff a bunch of mid-50 year olds would know... ;)

Here's the mains were using: http://audioheritage.org/vbulletin/showthread.php?t=15570&highlight=sp215-9

with a Yamaha EMX5016CF powered mixer: http://www.yamaha.com/yamahavgn/CDA/ContentDetail/ModelSeriesDetail/0,,CNTID%25253D450962%252526CTID%25253D227800,00.h tml

When I need more power, I just add one of several different amps on hand...

John

[boputnam]

...for use as the occasional mains...Actually, they will suck for that.

There is almost no useable bottom-end that "projects" into the house. Remember, these are not properly sized/ported cabinets. They have limited bass response that rolls-off pretty drastically - fine for a stage wedge, but not really suitable for "mains" unless you are really stuck (and all of us have been at least once... :o: ).

[Zilch]

During crossover design, it was suggested by one who knows that I incorporate a highpass filter around 80 - 100 Hz, because the stage is awash in bass, being behind the mains, typically, and adding more of indeterminate phase serves mostly to compromise the purpose of stage monitors, which is clarity for the performers.

I consulted with John, and he uses active EQ on the monitors to do just that. LF response was thus not much of a consideration in these, though John enhanced and smoothed it a bit with ports.... :yes:

[boputnam]

LF response was thus not much of a consideration in these... :yes:I have no idea what you posted, but think this excerpt resonates with my post.

[johnaec]

I have no idea what you posted, but think this excerpt resonates with my post.When I first talked to Zilch about these, I was planning on using sealed cabinets, since LF response wasn't paramount and I usually end up EQ'ing some out of the monitors anyway. But after looking at the closed box response, decided it was too much cut, so decided to add ports, which I noticed JBL also does in their small monitor cabinets.

John

[ssgreg@comcast.]

Nice professional job! Pat yourself on the back.

[Duffinator]

John,

Those look great with the Dura-Tex on them. Your wood working skills are fantastic and those speakers sounded great. I really liked the way you did the grills on them. It was nice meeting you that day at the Zilchlab.

Where do you buy the Dura-Tex?

[johnaec]

Thanks, Duff! 'Nice meeting you too! I purchased the DuraTex direct from the manufacturer: http://www.acrytech.com/store.asp?pid=14119 . I used the standard roll-on version, but not with their textured roller. I just used a little 6" cloth roller. Once it gets tacky, (about a minute), I re-rolled it lightly to raise the texture.

John