Budget Diy Metal Mini Monitor

Systems

I came across this design on Zaph audio's site and thought they would be a perfect choice to handle the surround duties in my HT.The drivers are relatively inexpensive but they offer excellent performance for the money.
The tweeter is Vifa 1"aluminium dome($15) and the woofer is a 5.25 " aluminum coned unit from MCM($18).
Ofcourse even the best drivers in the world will only sound as good as the crossover that blends them together.For this pairing Zaph has used his considerable design skills and developed a 24 db Linkwitz Riley xover at 2k.

Parts quality is in line with the price level of the drivers.(No $40 Sonic Caps for the $15 tweeter).Instead in the tweeter circuit there is a Bennic polyprop and 2 Eagle resistors and a Solen air core coil.

The woofer circuit has a 12uf mylar cap,1 eagle resistor,.4mh air core coil; and a 2.7mh steel laminate coil.While I would prefer using an air core in place of the steel laminate, a 10 awg would be required to get the correct DCR value and would cost an incredible $88 each vs $15 for the SL.

ben62670

Nice box. How are you going to finish it? I think that 5.25 needs a bigger magnet:)

ShinAce

1) That box seems big. What is that, like 0.3 ft^3 on a 5"? Just how low does this 'monitor' play?

2) Define budget! What's the total damage?

3) Damn you do some nice woodworking. I can see you probably feed the tablesaw by hand(unguided), but the recesses are flawless.

Systems

ben62670 wrote: »

Nice box. How are you going to finish it?

Thanks Ben.I will veneer the sides , top and bottom and paint the front and back panels with a textured black.I plan to build some matching 24" stands as well.

ShinAce wrote: »

1) That box seems big. What is that, like 0.3 ft^3 on a 5"?

Good guess;) just over .3 ft^3.Even though the magnet on the woofer is larg-ish for 5 incher (as Ben pointed out)it's actual Qts is on the hi side at around .5 thus requiring a bigger box.

Just how low does this 'monitor' play?

Low 50's.

Define budget! What's the total damage?

Without counting the MDF and cost of shipping parts from the US of A it's approx $150.

Damn you do some nice woodworking.

Thanks

I can see you probably feed the tablesaw by hand(unguided), but the recesses are flawless.

Your good,how can you tell that from the pic's?Actually I used the fence as a guide and a stacking DADO blade.It does a nice job on MDF.

Systems

ShinAce wrote: »

Just how low does this 'monitor' play?

Oh forgot to mention it will be ported.(had'nt yet cut the port opening when pic's were taken).That is how it can dig into the low 50's.

ShinAce

In the pic with all sides mounted except one, you can see the bracing piece of wood has the telltale arcing saw mark of a piece of wood that jittered. I spend a good amount of time sanding these bad boys, as my table saw is small for the pieces I'm cutting.

I haven't looked at the effeciency of that woofer, but I get the feeling it's <90dB/W/m. I hope she has a smooth response.

zingo

That is amazing woodworking GV. There is nothing like good craftsmanship on a speaker cab to set it apart.

ShinAce

Yeah, you definitely have the attitude of building it right the first time.

Systems

ShinAce wrote: »

In the pic with all sides mounted except one, you can see the bracing piece of wood has the telltale arcing saw mark of a piece of wood that jittered.

Good eye.;)

I haven't looked at the effeciency of that woofer, but I get the feeling it's <90dB/W/m.

It only 86db-ish ,the final system response is somewhat lower .

I hope she has a smooth response.

Yes very smooth through the mid band until 10k were a break up mode shows it's ugly head.But the xover is low enough that the peak isn't a problem.

Here is the data sheet for it. http://www.mcmelectronics.com/content/ProductData/Spec%20Sheets/55-3870.pdf

And here is the details on the design. http://www.zaphaudio.com/ZMV5.html

zingo wrote: »

That is amazing woodworking GV. There is nothing like good craftsmanship on a speaker cab to set it apart.

Thanks Zingo.Having the right tools is a big help.

ShinAce

While I'm on the GV constructive criticism trip, your hole saw that you used for the tweeter is either dull, or your drill press is leaning to the side(is that possible?).

Do you build on weekdays? First impressions of the final product?

One last real question. What is the attenuation on the tweeter? Those resistor values seem low for a tweeter L-pad.

edit: did you drill the tweeter hole from one side only? Even for MDF, I drill from the front about halfway through the wood, flip it over, and finish from the back using the same pilot hole. I've built mnay arcade joysticks and the button holes come out to about an inch. Since you need to use a big old plastic nut on the inside to hold the button down, I got into the habit of always drilling clean holes.

RuSsMaN

Very nice, where do we place an order?

Systems

ShinAce wrote: »

While I'm on the GV constructive criticism trip, your hole saw that you used for the tweeter is either dull

What ya mean I don't see any burn marks.:D Yep it was dull ,I should have bought a new one before using it on this project.Its trash now.

Do you build on weekdays? First impressions of the final product?

Usually just weekends. They are still at the stage shown in the pics so an audition is likely weeks away.

One last real question. What is the attenuation on the tweeter?Those resistor values seem low for a tweeter L-pad.

The 5 ohm series resistor is knocking off about 4-5 db.The 2 ohm shunt res is a lot smaller than normal but as the designer mentions the lower resistance helps to damp a peak at the bottom of the tweeters response.

did you drill the tweeter hole from one side only?

Yes,I did it straight through from the front.I didn't care if it looked a bit rough on the inside as it won't be seen.

RuSsMaN wrote: »

Very nice

Thanks

where do we place an order?

Madisound will sell you the parts and Home Depot the wood.:D

ShinAce

GV#27 wrote: »

They are still at the stage shown in the pics so an audition is likely weeks away.

Nuts!

Systems

I have the xovers done,not the neatest but it's functional.I used some peg board for the low pass,and just glued the hi pass to the terminal plate.

Systems

Its been over 4 months but I have glued up the boxes,painted the front and rear baffles,installed the crossovers,terminal cups,damping material and bass reflex ports.Aswell in an effort to extract the maximum performance from the little woofers I wired them with MonsterCable.:D:eek:

Now I just need to slap some veneer on them and finish the matching stands.I hope to be done by Christmas.

zingo

Those look great! Although, I hope you get them done before your ETA...

ShinAce

That first pic(post 15) makes me jealous. All in all just a nice build. Your patience shows in the details.

My broken olecranon(the elbow part of the ulna) is teaching me all about patience.

Face

Looks good bud!

Systems

Thanks. Part of the delay was because I scrapped the baffles shown in the first group of pics and re did them as the drivers did'nt sit perfectly flush.I dread doing the driver recess's so it took some time to build up the courage to do it. I'm cutting the veneer tonight.:)


Take care of that broken wing Shin.

schwarcw

Very nice job GV! It's nice to have a few dedicated DIY guys at Club Polk. Ben, Nick, Fred and some others do a nice job. Thanks for sharing your work!

Congrats!

Systems

Thanks schwarcw.

ben62670

So how do they sound!? Have you tried the correct rabbit bit for the recesses?

Systems

I won't be listening until Im completely finished the veneering.
On the first set I used a 1/4" spiral bit,and on the second a 1/2" straight bit.
I didn't test my depth properly the first time.:mad:

Aswell I need a Jasper jig.;)

ben62670

Yes you do. The Jasper jig is worth its weight in gold. I do use a rabbit bit when I can to do the recess for drivers:)
Ben

megasat16

GV, Very Nice Job! Wish I could do woodworking as good as you and Ben.

Ben, I have router buddy and haven't used it yet. Is jasper jig easier to use than Router Buddy?

GV, What's your impression on your monitor build? I read about Zach's Design a few months back and always thought of building one but slacking off in many forums hasn't produced any real work so far.

I probably should spend less time chasing after my tube preamp dreams and start doing something useful.

ben62670

I have not checked into the router buddy much. From what I see it will work fine, just make sure the screw that keeps the circumference in order doesn't loosen up:)
Ben

Systems

megasat16 wrote: »

GV, Very Nice Job!

Thank you

GV, What's your impression on your monitor build?

I assume you mean my impressions of how they sound.I hope to have them done this weekend so I can have a listen.

ben62670

GV#27 wrote: »

Thank you

I assume you mean my impressions of how they sound.I hope to have them done this weekend so I can have a listen.

Dude I am going to report you. PF is a bad place. Stay away!
Ben

TECHNOKID

A pair of Canadian pride GV#27 I hope your listen is worth your patience, skills and perseverance! Soon to enjoy the pay offs!

Ender

Wow. I love the pictures of the progress. It helps me understand what work and planning is required to build proper speakers. Thanks for sharing! And damn good work on these too!

Systems

Thanks TECHNO and Ender for the kind words.