WIN ISD Pro and multiway design

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Hi Steve, yes DCR in the sim should be set to the DCR of the actual coil. There are three discreet resistors. The 5.6 in the zobel on the tweeter, 1.8 ohms in series with C18 in the mid circuit, and the 3.3 ohm pad resistor on the tweeter. Sorry if the previous post was a bit confusing. You can subtract the DCR of the coil from the 5.6ohms of the zobel resistor if you wish. This will more accurately match the sim, as the sim as it stands has NO DCR for that particular coil :)

Tony.
 
Tony
A little bit confused now....
There is no Zobel on tweeter in PCD but there is a series RLC circuit....
I understood from my learnings (not always top of the class) that a Zobel consists of a capacitor and a resistor.
If I understand yr last post of 24 March, I am supposed to subtract resistance of 1.0mH coil from 5.6Ohm resistor?

I tried to order from Speakerbug just before Easter but they did not answer telephone and did not reply to email request to confirm cut-off dates for Easter orders until 2.20pm on 27 March for a 4pm cut-off on orders.
In short I have not ordered yet.

Anywhere to leave red soldier or someone at home?
Hope you had a good Easter!

Cheers
 
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Hi Steve, my bad. Getting my terminology wires crossed.... I should have called it a resonant peak filter :) Got confused becuase both are used for flattening impedance..

Yes you can deduct the DCR of the coil from the 5.6 ohm resistor. I guess the point there is that you don't need to worry about a low DCR coil in that position as there is a resistor in series with it anyway. If you use a highish DCR coil say 1 ohm The you can drop that 5.6 by around 1 ohm so a 4.7 ohm resistor would be fine (note that was just an arbitary figure I pulled out of the air).

Easter has been good. I'm on holidays so may or may not be around, but if you know you are going to be in the area I can hopefully fit in around that :) I'll PM you.

Tony.
 
Quick update:
Very steep learning curve still.
A huge surprise has been size of components from Speakerbug. Not the tiny circuit boards and components I have seen in computers, tvs etc.
Also had to find out how to wire coils, apparently it doesn't matter which way round just like resistors and capacitors.
And Speakerbug let me down again, running out of speaker wire for internals.
Have devised double decker circuit board as speakers cannot fit physically on circuit board.
Will post photo next week.
3way PCBs from Jaycar were a waste of time as components did not fit on board and circuits for mid and tweeter are different.

Hope to melt solder in anger next week

Cheers
 
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Hi Steve, that's a shame about the crossover boards :( Jaycar have had a few over the years, some much bigger than others, I guess you got some small ones.

I made my crossover on masonite with stripped enameled copper wire (same 14ga stuff I used to make the coils I think) for routing between components. The components are held down with cable ties through holes in the masonite. There are a few pics of the construction in this post --> http://www.diyaudio.com/forums/multi-way/68301-my-morel-mtm-project-7.html#post2740570

Note the orientation of the coils. I used this info from Troels site for working out my coil placement. Placement of coils in crossover networks (yes there is just more and more!!!) :p

Tony.
 
Yes,
The orientation of the coils next to each other is important as they can change the electrical values through coupling of the magnetic fields. I like Tony use a wood base to mount passive crossover components. I use both hot melt adhesive and zip ties to hold the heavy components in place. Always try to have coils at 90 degrees to the orientation of any next to each other and never stack any inductors as they will mutually couple and change inductance. Glad to see you two are still working together on this design exercise.

Steven
 
Hi

Finally got all components after being let down by Speakerbug again (grrr!)
Attached is dry run asembly of components for comment and feedback.
As in previous post i was surprised by size and weight of components, necessitating woofer components to be put on separate board.
Arranging the components to simply fit on boards and form correct circuits was challenging!
I had the idea of using crimp connectors for some components rather than bring more wires back to solder tags. The idea for solder tags came from Troels Gravesen website.
Peg board did not seem strong enough for the components.
Note tails of components have not been trimmed yet or in some cases properly located.

I am probably about to commit some classic no- nos so please don't hesitate with any comments.

Cheers
 

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Just another Moderator
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Hi Steve,

when working out my coil placement one thing that I read (I can't remember where) was that you should look through the centre of the coil. If you can't see any other coils then that is good. This is useful when turning the coils on their side. I'd be looking to move the coil I have arrowed 1. Probably putting it where the 56uF cap is and changing it back to a normal vertical mounting. It should be far enough away from the similarly oriented coil in the top right corner to not cause any problems.

You could then possibly move number 2 slightly further to the left and lie it down, looking throught it would be north south.

You have two avenues. Distance (20 cm between coils) or orientation. The orientation of 3 and 4 allows very close placement of the coils. It is the best orientation for minimizing interactions when things are tight. If you do move 1 as suggested it should be fine even in close proximity to the woofer coil.

Tony.
 

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Thanks Tony
Will look at doing this. As there are 6 coils and 3 possible orientations, two will always be the same!
Any opinion on crimping v soldering? I see from yr Morel photos you have put ends of wires parallel and then soldered together for about 10mm.
Also piggy-backing resistors on capacitors is a good idea!


Cheers
 
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Just another Moderator
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Hmmm I always solder, but I don't have a proper crimper. From what I have read, a properly crimped connection (and I've only heard of it with stranded cable) should have better electrical contact than a soldered one.

I'm not sure that my soldering was best practice. There is no mechanical attachment, but it was the easiest way for me to get a clean joint. The 14 gauge wire makes it a bit difficult to twist together. With your tag strips wrapping the wire around the tag and then soldering should be the best option I would think.

Tony.
 
Hi everyone

I am pleased to say that this weekend I finally finished my speaker project and I am very pleased with the results.
The bass is less pronounced than previously and the mid has really filled out, producing great definition and a very clean, crisp sound.
Top end distinct, but not overwhelming.

Basically since last post of 12 May I have been spending what little spare time I have had on reconstructing the cabinets and very challenging this has proved to be.
I think ultimately reconstruction was not a good idea and it is better to start from scratch, but anyway, here is a brief over view for those interested.

Not possessing woodworking tools such as routers and wary of my ability to cut perfect holes in new baffle with a jigsaw, I opted for a sandwich of 12mm and 6mm MDF with an added veneer of Tasmanian Oak. This was on basis MDF was easier to work with and veneer would be easiest to make perfect circles in and hide any irregularities in cut-outs for drivers.
This unfortunately probably doubled the amount of work.
Locating veneer suppliers was not easy, and finding suppliers who did not have minimum charges even harder. Eventually Amerind at Ingleburn were able to help, supplying me a ‘flitch’ for $50.
However cutting and working with veneer proved to be very difficult, the wood splitting and tearing very easily and being very difficult to glue perfectly to MDF. I experimented with a number of techniques using different PVA glues, presses and finally a warm iron. Even when veneer looked good, a few hours later wrinkles would appear. A good move was to use a hot iron on veneer before gluing to reduce moisture content, this reduced a lot of the wrinkles and bubbles.
For the first cabinet I produced, I removed the original baffle and glued new baffle in its place, leaving square edges which again required some tricky veneer work. The new results were not very good so I decided to put some Tas oak half round quad edges on new baffles which looked much better and would eliminate any bad acoustic effects from square edges.
Doing this meant I probably could have used a pre glued timber veneer board in the first place… (but would still have had driver cut-out issues).

Once the first cabinet was finished and speaker assembled, the second one plus second cross-over was done in a matter of weeks.
I used lessons learnt in doing first cross-over to improve second, especially with regard to coil placement. The veneer is still not perfect and will requires some regluing in places.

Mid driver was placed in a separate 150mm PVC pipe compartment which seems to work well, hole for driver wire entry was plugged with sealant.

I am still amazed that sounds come from my clumsy soldering attempts at cross-overs and that the speakers work. Our kitchen resembled a bomb making scene from films at times, much to my wife’s disapproval. But she hated the old speakers with their dark brown artificial wood vinyl and is even more impressed with the way speakers now sound.

So after 30 years of service, my old speakers have a new lease of life and I finally have a pair of quality speakers which to my ears sound fantastic. No more will I go into Hi Fi shops and look longingly at the $3000+ speakers…
I am now happily playing my favourite CDs (very loudly!) much to my family’s annoyance.
Amerind have some very nice veneers so may contemplate a new project in another 10 years….

It has been a steep learning curve but ultimately very rewarding. I am very grateful for the assistance and advice provided by members on this site, especially Tony.

So if any other ‘newbies’ are contemplating such a project, I would say, ‘Go for it!’

Cheers
 

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Just another Moderator
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Excellent! I'm very pleased to see you re-did the baffle! I think that will have made a big difference for off axis listening! They look very nice!! :)

Very glad to hear that you are happy with the sound, and that they have turned out well balanced, It's a great feeling listening to your creation isn't it! :)

Tony.
 
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