Planet-10 Maiko 2

[richidoo]

Last summer I built a pair of these. As far as I know I was the first and only builder of these so far. The 1st Maiko design was compromised for non-technical reasons and proved to be a disappointment after many hours of carving and assembling the parts. The new design is very optimized, and very different. It is smaller and has none of the problems of the 1st.

Bass seems to reach to about 50Hz, which is pretty good for 3.5" driver, the Feastrex D5nf, for which this speaker is specifically designed.  The cabinet has a coupling chamber to catch the back wave, then through a large tuning port/vent and on into amplifying horns. Nicknamed BVR for big vent reflex, it is a great invention of Scott Lindgren (from UK) for single driver speakers to boost bass. Bass is low and clear.  Many of the planet-10 speakers use this concept.  Maiko 2 has angled sidewalls to reduce internal echo. But the rear wall of the horn is angled upward, giving a compound angle on those horn backs. A digital blade angle gage, free CADstd software and some creative layout and calculations helped me to determine the blade angle for the compound cut, which was listed incorrect on the plan. Early adopter hazard. hehe

I made it to plan except for 2 mods. Instead of internal bracing, I laminated another layer of 3/4" MDF onto the outer panels with greenglue, notched trowelled on in an even coating as Bryan suggested. This worked really well to reduce resonance in the side panels. I could hear the resonance decrease over a few days as the goo solidified. Next speakers I build I will use 1/2" MDF or plywood and use 2 layers of green glue instead of one. The other mod is experimental, I cut the front baffle into two unequal lengths, the short is glued on permanently, the longer one holds the driver and can be inverted to move the driver to the top of the baffle for improved imaging height, or move the driver to the center of the coupling chamber which is lower image height but that's how the bass system was optimized. It puts the driver equal distance from the vents, so the bass peaks will combine in phase to give clearer louder bass. I can always put a sub driver in a box under the speaker, to raise it up.

So far it sounds pretty good. After a couple months puttering with stuffing I started to hear the problems. Every diy speaker has problems to be worked out. For a while I was chasing a lower midbass resonance that no damping or stuffing could kill. I finally realized it was the unglued front baffle vibrating with the driver. I left it unglued so i could experiment with driver height. Plans wants it in the center which is pretty low. So I moved the driver as high as possible but this is supposed to compromise bass so I didn't glue it in, and the vibration of the baffle was severe, even tho it was wedged between the angled sidewalls. Today I made a support ledge up the inside edge where the baffle meets the sidewalls so the baffle will sit tight against th ledge and I will glue the lower permanent part into the speaker tomorrow. I am looking forward to hearing this thing play clear and low.

The Manley 300Bs are a good match to these drivers. The drivers are 91dB/w/m 14ohms so probably more like 93db. Then the horns will add some SPL too because some midrange does come out of the horns. Hopefully I'll have it tuned up and finished for the next g2g. It's only been 2 years since I bought these drivers!  Time to fess up!

Been using zip wire to the screw terminals on the speaker, need to install some posts and solder the internal wire to the voice coil leads, then I can use the JPS on them and get liftoff. Tomorrow if all goes well.

Well the reason I posted on this and broke the silence after 6 months since building Maiko 2 is that I tried to do a tweek today when I was chopping the baffles in half. I wanted to stiffen the chopped edges that are floating in space vibrating freely. So I cut some roofing flashing aluminum (.020" thick) to precise shape of the ends of the boards. Sanded them rough, and used super West Systems epoxy to glue them on. 45 minute cure time came and went. The joints stil kinda sticky, WTF? 3 hours later I took it apart, the glue was still wet and the metal parts peeled right off. 4 hours wasted. That is the second time that exotic glue screwed me, so in the trash it went. I was frustrated and needed a place to vent. But by now I'm settled down. No need for pity. But thanks for reading anyway....

I'll put some pics up tomorrow after it get it back together. Then onto paint Ralph Lauren Sargent Green to match my fireplace mantle which these speakers will straddle.
Rich

[Rob S.]

Way to get busy Rich,  sounds like a fun project.   CAn't wait to hear them.

rob

[Carlman]

cool...   Can't wait to hear them either..
If I understand right, could you use simple L-brackets in the corners to firm up the free floating baffles?  You can even bend and twist them to conform to odd shapes.  Not elegant but effective.
Looking forward to pics!
-C

[richidoo]

Thanks for the idea and encouragement guys. Once I decide which I like better I will glue it all down tight.

[Bob in St. Louis]

Post pictures or it didn't happen. 

[richidoo]

Oh, it happened alright....


New holes drilled for driver mounting and binding posts, internal wires made, binding posts reclaimed from chip amp project, but no paydirt today. Kids piano lessons and a nice long sunny walk around the frozen pond with wifey took priority.  Tomorrow, I promise. As you can see, my wife is an audiophile's dream woman. Sitting happily among the wreckage.

Notice the two Feastrex drivers face down to the right. And the Maiko2s in the back left, FG guts showing. Baffles on the floor in foreground. Use your imagination to put them together. 

[Rob S.]

 

all you need to complete the picture is a couple of kids working on homework amongst the disarray.   Did you at least have some music on during this?

Just finished making a bigger mess in my audio room, so I enjoyed your photo all the more.

Need more pictures.

Rob

[JLM]

I had to make a bit of sawdust myself this weekend.  I enlarged the holes in the back of my speakers so that I could run speaker cables direct from my monoblocks to the Fostex F200A drivers.  It's ugly (like it was done by a complete amateur (yes it was), but rope caulk should take care of the now oversized holes.

Don't know about you guys, but it drives me nutty thinking about having nice/heavy speaker cabling in place just to leave the last little run to whatever wire the speaker builder used.  Almost as bad, to have them use a cable that isn't anything like your chosen cable.  Specially when you're running with a single driver anyway.

(In 2009 replaced zobel/baffle step circuitry with a modded Behringer DEQ2496 in part to provide the most direct connection between amp and drivers possible.  This is supposed to help synergy between the two.)

[richidoo]

Did you at least have some music on during this?

Of course!! Pandora the Bebop/Combo shared  station. 

Don't know about you guys, but it drives me nutty thinking about having nice/heavy speaker cabling in place just to leave the last little run to whatever wire the speaker builder used. 

It is usually pretty surprising to see what's inside a commercial speaker. They figure it's good enough, you can't see it, and you don't know the difference anyway, so save a 1000 in costs and use the crap parts. My legacys had nylon disconnects you see in a car wiring harness on the crossovers. Made it very easy to remove, but not ideal for signal transmission. OtOH,  good enough is good enough. They sure made nice music.

I'm using same brand wire inside and out, but I only have Dayton posts. Good enough for now.

[Rob S.]

Rich,   need some updated pictures on the speakers, seems like you were 99% done.  Got them fired up yet?   

Craving an update....

[richidoo]

Yes they are finished, sorry for slacking off on the updates. The Ushers are gone so these are taking over for the next week or two anyway. I'll put up some pics later after gokarting.

I'm gonna have to rebuild them in Baltic Birch or White pine. The MDF that I'm using now dulls transients and smears things due to wideband vibration. The real woods vibrate but higher Q. I really want to make the next cabinet from aluminum plate, damped with wood or bed liner goo, etc.

I'm building some current source amplifiers for them, designed by Sol Samet. That makes a HUGE difference on single driver speakers, a whole new beast. That should be ready in a week or so.

[rollo]

Busy as a Bee. How cool is that building ones own speaker and amp. 


charles

[Bigfish8]

Rich:

I know you are having fun with this project and cannot wait to hear your comments about the sound when you are finished.

Ken

[bpape]

Absolutely looking forward to it.  Now where's that munching popcorn emoticon when you need it...

Bryan

[mgalusha]

Now where's that munching popcorn emoticon when you need it...