Construction journey-Active 3-way

[ttan98]

Hi HYPERTUNE,
Thank you for the link. Good luck with your project.
No, I didn't know about these. This would be more what I'm looking for, but they are so expensive! For the 2 channel kit it would be ~$850.00 plus transformer and a chassis to put it in. That would be 3 times as much as the Behringer.

I haven't completely ruled out building another analogue active filter - one that can be easily adjusted, such as the one designed by Jens Rasmussen. This was the problem with the original, it's lack of adjustability.
As suggested by another member, the DCX would let me determine the correct xover points and slopes which I could use to develope a dedicated analogue unit. This is more to my liking.

To save some money I recommend(I use them myself) chipamp for driving the mid and tweeter, LM3875 for both mid and tweeter and high powered commercial amp or use one of the national chip LME49810 with discrete o/p transistor. Depending on the effciency of your woofer, a 100W amp is suffcient.

I build my own amp and if you use all chipamp I suggested above you will not spend over $500(I spend less than $400 incl. transformer), ie 6 channel amps. If you need more info leave a message here. Because I went through that path I can advise you what is the best way to save money same time gives you good performance.

With this combo I am confidence that you would be happy with them.

PS. I still recommend DCX2496 if you want to develop speakers. I am happy with mine, if you stop developing you can sell them quite easily without losing alot of money. It is very flexible, 2,4,8 order LR or 2, 3 rd Butterworth or even Bessel function, also many other features you never use. That's a fact. Most impt. easy to use.

 

[MJL21193]

To save some money I recommend(I use them myself) chipamp for driving the mid and tweeter, LM3875 for both mid and tweeter and high powered commercial amp or use one of the national chip LME49810 with discrete o/p transistor. Depending on the effciency of your woofer, a 100W amp is suffcient.

Hi ttan,
The price I quoted above was for the digital crossover kit alone, no amps.

I have already built and used an active amp project for these speakers using chipamps (LM3886). Details earlier in this thread and a whole other thread devoted to it's construction.
The chipamps work fine, but I think there is room for improvement. That's why I'll go with class A on the tweeters and discrete class AB on the mids and woofers. That aspect I have covered, as amps are not my immediate problem.


The active filter is my problem. I'll be building the
Active Filter One from Delta Audio. This seems to have the flexibility that I want.

 

[Dr_EM]

Would it be possible to just construct the crossover on breadboard and tweak until you are happy before building your final design? I guess your not convinced you will remain happy with this sound and may want to tweak further? I plan to sample my crossover on breadboard before assembling it.

That crossover/filter you linked is a monster! Your clearly not scared of op-amps

 

[planet10]

PS. I still recommend DCX2496 if you want to develop speakers. I am happy with mine, if you stop developing you can sell them quite easily without losing alot of money. It is very flexible, 2,4,8 order LR or 2, 3 rd Butterworth or even Bessel function, also many other features you never use. That's a fact. Most impt. easy to use.

Indeed... very useful for developing XO topologies... i find that it doesn't sound very good, and i have to listen thru that short-coming. When i get my own (instead of a loaner) we'll be going in and doing extensive mods,

dave

 

[MJL21193]

Would it be possible to just construct the crossover on breadboard and tweak

That crossover/filter you linked is a monster! Your clearly not scared of op-amps

I can't use a breadboard. The last time I tried, I discus threw it into the forest behind my house.

Yeah, I'm not afraid of a few opamps. The board has a ton of functionality, some of which I may not use. With that said, I may go back to design my own or still use the Behringer.

Indeed... very useful for developing XO topologies... i find that it doesn't sound very good, and i have to listen thru that short-coming. When i get my own (instead of a loaner) we'll be going in and doing extensive mods,

dave

Hi Dave,
When do you get the chance to use it? I thought you're a one driver man.

 

[spind]

John,

I've enjoyed watching your speaker your amp projects progress. Great work and fabrication skills! I wished I could move through some of my projects at 1/10 of the speed you have.

That said, I think I have hidden away some of the MOX-like crossover boards that moamps designed several years ago. Information on these boards can be found here: http://www.diyaudio.com/forums/showthread.php?s=&threadid=32095&highlight=

PM me if you are interested in these and I can see if I can find them for you,
Steve.

 

[planet10]

When do you get the chance to use it? I thought you're a one driver man.

For stuff like this...

dave

 

[planet10]

1st round, in room FR (top limited by the ADC in the laptop (speaker should be good well above 20k)

 

[planet10]

... and this

 

[MJL21193]

That said, I think I have hidden away some of the MOX-like crossover boards that moamps designed several years ago. Information on these boards can be found here: http://www.diyaudio.com/forums/showthread.php?s=&threadid=32095&highlight=

PM me if you are interested in these and I can see if I can find them for you,
Steve.

Thanks Steve,
At this time of the year my work load is light, so I have lots of time to play with this stuff.

I appreciate your kind offer, but I'm not sure yet. Thanks for pointing out this design. I'd seen it before, but didn't look closely at it..
The MOX has me thinking. I like the way this is designed and I may go to the trouble of doing a board layout based on this. I'd want it to use dip switches and dual opamps (as opposed to discrete opamps on daughter boards).
I'm thinking 2 - 12db filters on one board, so for two 3-way speakers I'd need 4 low pass and 4 high pass, input buffers, output buffers. Not the most tedious build of all time, but pretty close.

 

[MJL21193]

... and this

Do you have enough speakers there?
I have a similar scene, but mine are all real speakers and in various stages of completion/metamorphosis.
Latest transmutation is the pigment change to the body of these 3-ways. They have gone from stained wood veneer to smooth black matte paint.

 

[MJL21193]

Bodies are black, baffles are...maroon! Pics later.

I have done a very nice board layout for the active crossover. Low pass is done and I'm now working on the high pass. These will have nearly all of the same adjustably as the original MOX, the only difference is mine will be 12db or 24db only.
These use dip switches instead of jumpers and each board has one dual opamp. There will be a single input buffer for each stereo channel and 3 output buffers with trimpots to set the level.
I will build this into it's own separate chassis.

Here's how the low pass board looks. I'll need 4 of these.

 

[MJL21193]

Bodies are black, baffles are...maroon! Pics later.

Well, back to black for the baffles.
I made a silly mistake. I was out last week to buy work supplies and stopped off at Canadian Tire (department store with auto parts) to get something. I went to their auto paint department, where they sell spray cans of paint mostly. I saw a new product - Duplicolor "Paint Shop" lacquer. I looked it over and thought if it's good enough to paint a car with, I might as well give it a try on the baffles. Bad move.

Long and short of it is that this paint is trash. I sprayed the colour and it went on less than smooth. I'm not used to so much orange peel. I then sprayed the clear, and the colour changed a bit. OK, I can live with that I guess. Leave it overnight.
The next day I'm looking it over and I notice that it's still soft. Not that I'm in any rush to sand, but I'm looking for higher performance here, not a step backwards.
I decide then and there to get it off. I try it with a plastic scraper and my heatgun. Pretty much slides right off, without damaging the black urethane paint underneath. I get them cleaned up and resanded. Thin some more of my waterbased black urethane paint and shot that on, 1/2 litre each speaker. Body and baffle.

I will leave them like this until I get the real paint and clear and quit ******** around with junk store garbage.
Another lesson learned.

 

[ShinOBIWAN]

I will leave them like this until I get the real paint and clear and quit ******** around with junk store garbage.
Another lesson learned.

Duplicolour is the lowest of the low. You can get it over here too and usually in rattle cans intended for bodge jobs on cars.

If your wanting auto paint then the best there is would be PPG. From Ferrari to Fiat, virtually every factory finish is using their product. They have a vast range spreading from waterbased to solvent to epoxy and everything between. They even supply the paint they use any of the modern US fighter jets.


Link here to auto products:

http://corporateportal.ppg.com/NA/Refinish/PPGRefinish/

Link to PPG general including industrial finishes:

http://corporateportal.ppg.com/NA/Refinish/PPGRefinish/

I used to use Upol but after a rep from Anest Iwata visited to sell and advise on a couple of new spray guns he baulked in disgust. This is a guy who works with paint manufacturers, spray shops, automated production lines, industrial finishers. He knows his product so I completely trust him when says that PPG is the best. I switched to their "Autocolor Belco" clear and "P084 rapid primer filler" pretty much straight away. Its as close to 2k performance as I've witnessed from 1k, particularly the clear. I'd love to try their 2k range but I can definitely live with the finishes I get now without the hassle of 2k. Only downside is its expensive but that extra you pay goes towards not losing your sanity. A small price to pay IMO.

You might want to check out their Envirobase:

http://corporateportal.ppg.com/na/refinish/ppgrefinish/2-0-Products/2-05-Envirobase.htm

Or the Aquabase plus ranges:

http://corporateportal.ppg.com/na/refinish/ppgrefinish/2-0-Products/2-04-AquabasePlus.htm

Both are leading waterbased finishes.

Other than that I'd recommend the Nexa 2k or Global Refinish System.

 

[MJL21193]

The Duplicolor was pre-mixed in a 1 litre can, ready for spraying. My first time ever using lacquer and I can't say that it made a good impression on me.

I have pretty much committed to the AWX waterborne basecoat/clearcoat from Sherwin Williams. A couple of good reasons: I am still jaw-droppingly impressed with the WB urethane paint - it's simply amazing. I have no reason to believe the AWX wouldn't be exactly what I'm looking for. Also, I have a commercial account at SW, so I get a discount and less of a run around as I know the staff.

Pittsburgh Paints is in the building right next to them, so I will check out their prices too.
I'm in no rush this time. I figure I'll let the paint I did today dry for a couple weeks or so, to make sure there are no mishaps this time.

Besides, I still haven't decided on a colour for the baffles.

 

[ShinOBIWAN]

Well good luck with it whichever way you go. I wouldn't worry massively about where the base/clear coat comes from providing its respectable quality. Primer is the most important layer in any finish, everything goes down onto that and if that moves, so will whatever is on it.

 

[MJL21193]

The consultant assures me the urethane paint is a good base for the AWX. Here's something that impressed me: It's nearly impervious to lacquer thinner (I used some to get the last of the krap paint off).
He said I could just use the clear AWX on the existing, to build a good layer for polishing. I want to explore some colour options though.

This gives me time to get the electronics in order: do the crossover (board layouts are almost done) and get the amps built.
I'm thinking 90 watts for the woofer, 60 watts for the mid and 20 watts for the tweeters (class A).

 

[MJL21193]

It's been a while. Overwhelmed with 12-14 hour work days plus several hours of travel each day, leaves me with no time on my hands to do anything.

The speakers are painted entirely black and have been sitting here with the drivers removed waiting for the next step. I've been thinking that it was a mistake to paint the veneer. They look too plain and boring now, even though they are not near finished. The black is what was left of my can of Armorseal urethane paint. I sprayed this on more or less as a base for what comes next.
What comes next? I'm considering just a low VOC 2 part clear coat on the baffles. The one formulated for the AWX paint above will work fine. This will restore the liquid black they were before.

For the body, I want veneer again. I want something different this time though, not the original maple (getting a bit tired of that grain now).
In particular, I want a veneer that I don't have to stain, but will naturally be a dark reddish colour. With this in mind, I have been looking at several from my supplier. I considered jatoba, makore, African mahogany, and sapele.

I have narrowed that down to sapele, either ribbon or pommeled. Below are the two, first is the pommeled. This is rather expensive at $316.00 for a 4' x 8' sheet of paper backed. The one next to it is the ribbon sapele, that's only $68.00 per 4' x 8' sheet.
I'm leaning toward the pommeled, as it really has a fantastic look.

Thoughts? Opinions?

 

[5th element]

There's always walnut burr

http://www.woodveneeruk.co.uk/products.php?cat=7&pg=1

if you're into that kind of stuff.

There's rosewood too.

 

[spind]

I have narrowed that down to sapele, either ribbon or pommeled. Below are the two, first is the pommeled. This is rather expensive at $316.00 for a 4' x 8' sheet of paper backed. The one next to it is the ribbon sapele, that's only $68.00 per 4' x 8' sheet.
I'm leaning toward the pommeled, as it really has a fantastic look.

Thoughts? Opinions?

The sapele is being used on quite a few guitars and looks quite nice, close in looks and sound to mahogany. The pommeled stuff is beautiful and can look 3-D when finished. I just bought an all sapele guitar (top, sides and back), but in the ribbon variety. I guess it depends upon your wallet and how much the top and sides will be visible in your room. The pommele could be a real standout!


Steve.