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Speakers: MUN17-3W

I like this thread as I like all the in depth threads about building speakers that allow me to vicariously satisfy my desire to build a great set of speakers which I lack the skill, equipment, space and time to do so.

However it seems there is a great deal of procrastination going on when it comes to the building of the blasted cabinets

(he says sitting here procrastinating about doing work on his work from home day).
 
Procrastination is second only to faffing in my list of DIY skills pmm. You'll be glad to know that I made some progress today... Nothing to do with speaker cabinets however! The hard part of one upper shelf for the rack more or less done - epoxied, flattened and rough sanded... Just three more to go






My working at home days tend to be the most productive, certainly. Just not for my employer.
 
Any suggestions on how to notate the connections in some fashion? I have zero engraving skills or access to fancy machinery. I don't really want to use ugly stickers if I can help it. I'll probably just want IN / OUT / LEFT / RIGHT or similar on the rear of the crossovers, and maybe something on the rear of the speaker if it's not too difficult...
 
If you're up for quite a lot of faff, how about something like this:

Not that I've actually tried it myself😂!
 
One crossover box glued up. I used some black resin for this as there was some spare from crack filling and it should blend in well with the enclosure.


 
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For one reason or another the resin glue up did not work... the same resin pour in the slabs cured normally so I suspect the ambient temperature was too low for such a small amount of resin to heat up enough to cure.

The second attempt was completed tonight with wood glue - a safe bet.

Back panels drilled:


Glue up take 2:
 
Dymo would probably do it, I'm just concerned it will look a little rustic...

3 out of 4 just about finished. They don't look perfect close up but once in a rack they should appear presentable


 
That looks ideal actually! I'll have a look at some reviews...

Boxes roughly finished... Just need to sort out the re-wire. For the inputs I'm going with banana sockets, and Neutrik speakon connections for the filtered outputs. For the full range outputs to the bass amps I've got some spare banana sockets to use up.

 
Today I stripped down the upper cabinets and mounted the crossovers in their final resting place. For the smaller tweeter boards they seem happy enough mounted with sticky pads and cable ties. For the heavier mid units these are screwed into little wooden blocks glued to the enclosure bases.

I wasn't sure what the best practice is with wiring methodology so I've gone with twisted. Mainly because it keeps things tidy and that's what Troels seems to do and if it's good enough for him I'm sure it's fine...







Thanks again to Dave @S-Man who did the hard part of actually wiring the boards up.

Onto the cabinets any day now...
 
@fraser. Those wood grains look incredible👍 - a quick learning question if l may, there are four external crossover boxes? Two for the tweeters and two for the woofers is this correct?

:)
 
Thank you :)

The crossovers are :
2x for the tweeters
2x for the mids
2x main outputs for the woofers which are actively driven and take a full output. I've taken these from the tweeter boxes which have a full output to th second set of banana posts.

I'm no electrician but in my head that's a reasonable solution! It means I only have to squeeze two sets of cables into each amp output.
 
Just thinking about belt and braces testing/commissioning…

1) if you have a DVM, test the input to the crossovers on the resistance setting. You should get either an infinite reading (on both mid and tweeter XO) or high and count t up/down. If you get a low or zero reading something is wrong - don’t connect your power amp!

2) after final assembly, disconnect your power amp speaker “red” leads (at the power amp end to avoid the possibility of shorting the amp output). Set some music playing at lowish level and dab one red lead on the amp output terminal. Obviously, you should get a brief burst of quiet music. Do this for both channels.

Actually, to be even safer, you could use the mid crossover into the mid range unit first and then try the treble crossover into the mid range driver. Even if you play it fairly loud, the mid range unit should hardly move if connected via the treble crossover.

Once you’re satisfied that only high frequencies are getting through the treble crossover and mid frequencies through the mid range crossover you can go for it.

Just one of the thought: ideally, you should have a foolproof method to ensure you can’t connect the mid range crossover to the treble unit.
 
S-Man said:
1) if you have a DVM, test the input to the crossovers on the resistance setting. You should get either an infinite reading (on both mid and tweeter XO) or high and count t up/down. If you get a low or zero reading something is wrong - don’t connect your power amp!
Click to expand...
If there is a shunt coil in the circuit, it would measure its DCR, which is usually lowish and might appear to be a short.
 
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