Another Wavecor Ardent build

[BobEllis]

Sort of the same thing as a vacuum table. As long as the substrate is non-porous it will pull a good vacuum. On a vacuum frame press the membrane is sealed to a frame with closed cell foam gasket, but I was trying to avoid multi direction clamping. See http://joewoodworker.com/veneering/v...rame-press.htm

[Steve Manning]

Very slick there Bob ..... I did not know you could do that trick on one face at a time. As an fyi, you can get dry rotary vane pumps, no oil at all. They are typically more expensive initially, but once you figure savings on oil and all that mess, not having to put the pump outside with long hoses, which is never good for conductance in a vacuum system, it's a nice way to go over the long haul.

[BobEllis]

Now you tell me. we'll see how much of a problem the outdoor pump is vs. How much I use it.

[Steve Manning]

What's that they say about closing the barn door after the horse has run away ..... the only reason I know about them is because of working with high vacuum systems for years, I've used just about every type of vacuum pump out there in some fashion or another.

[benthe8track]

Hey Bob great work! I mulled vacuuming bagging around for a long time but I just couldn't figure out how to do it. You should get superior results the standard cold press. Very clever using the mastic like that. FYI they do make sealant tape specifically for vacuum bagging, eg: https://www.acpsales.com/Vacuum-Bagging-Supplies.html I think the low temp stuff would work just fine and should stick to the epoxy coat on the baffle.

What are you going to do when you need to seal the bag to an already veneered surface?

[BobEllis]

Ben, since I am using epoxy to apply the veneer and it bleeds through completely, my surface is epoxy. I don't need to worry about the tape residue in the grain - hooray for a fortunate side effect. That certainly would be a factor using conventional adhesives.

Experimenting with what I had handy, I found that Windex, a Scotch-Brite pad and paper towel remove the tape residue quite nicely. Anything that may be left will be sanded as I remove as much of the epoxy as possible for finishing. The gray tape in your link looks an awful lot like what I am using. I think that issue I have removing it from the bag is the lightweight plastic I am using isn't strong enough. It seems to come off the 30 mil sheet I bought from JWW reasonably cleanly.

On the more work side, I found that the veneer does break at the edge, and not cleanly. Time to see how closely I can cut the veneer to size or more likely make some cauls. I think I can work quickly enough to get two facets bagged at a time.

[Renron]

Very cool Bob!
I'm glad your making progress, the vacuum process is intriguing. Thanks for the photo's and explanations.

Goo-gone and Goof Off are actually Toluene and Xylene based solvents. Very smelly too. Removes dried yellow glue too!
Here's a fantastic "Primer on Solvents"

http://www.popularwoodworking.com/article/a_primer_on_solvents

Ron

[BobEllis]

Thanks for that link, Ron.

Hoping I can get the veneer cut closely enough not to need cauls. Although the facets look quite straight to the naked eye, checking with a straight, flat surface, not so much. Maybe cauls will be thin HDF so they will bend a bit.

[BobEllis]

Finally a bit more progress. After trial runs, I decided two facets at a time were too likely to slip out of place, so it's one at a time.

First, I made a template to cut the facet out of the side veneer off cut. Who knew grave rubbing skills would come in handy? I cut out and traced this pattern onto the veneer. It gave me a piece that was about 1/16" oversize.



Prepping the bag. All laid out, a sheet of plastic under the breather mesh to keep the epoxy bleed through from sticking. I folded it back, wet both surfaces then flipped the whole mess down.



Here we are under vacuum. Running at 23" at the pump. It took a bit of mashing on the mastic to get the bag sealed reasonably well. I can still hear a little hiss, but overall it's sealing well. The veneer slipped, but pulling the vacuum fitting off of the bag allowed repositioning. The 1/32" free edge doesn't create enough of a lever to crack the veneer. I'll keep it under vacuum for 12 hours then let it continue to cure until tomorrow when I will trim it.



Yes, that is the living room, since it's too cold outside to cure the epoxy in a reasonable time. The pump is outside. Very understanding lady of the house is eager to hear them, too. I think I may miss my 12/31 target for listening, but not by much.

[dar47]

Bob your dogged determination to make this work come hell or high water is vary impressive, haha.

I think it will really pay off with wood to wood veneer joints at the facet edges but your paying for it with time so just enjoy and don't worry a bought deadlines, soon enough!

[BobEllis]

Funny. This is taking a lot longer than I'd hoped, but at least it's still moving unlike some other projects I've started. The completion target is more to keep me going. I've found that without some sort of deadline things just don't get done. If I do a facet a day I'll be done with veneer by Christmas. Then a day or two sanding, and if the weather gets warm I can put a coat of finish on.

[TEK]

I have experienced something along the same lines, but I have a different approach.
First - if you are like me, remember it is supposed to be something that you do because you enjoy it.
Often I get to carried away in a build and pushes on to get it competed. The result is that after the build is finish it takes a looong time before any new build - because it's just not any fun when pushing it that hard.

So now, if I do not feel like building - I just don't build. After some time the motivation comes back and I can enjoy the next part of the build.

BUT, and this is something that for me is quite important. I'm NOT allowed to start any other build as long as I still have not completed the previous build.
If I do not have that rule it would very soon just stack up with unfinished builds - so I think that is an important rule for me.

But of course, everyone must evaluate what works for them - the same methods will probably not work for everyone.

Jon: how many builds do you have going? :rofl::rf

[BobEllis]

Lack of progress was due to not feeling like it and concern it might not work as planned. Finally felt like giving it a shot.

The vacuum pump is misting quite a bit. Glad I have the pump on plastic. It's making an oily mess. This pump may get relegated to rapid pull down assistance.

[BobEllis]

I'm happy with the seam, but not so happy with how much the mastic stuck to the surface. Leaving it on 20 hours made it a lot harder to remove than my ten minute test showed. I'm going to investigate using closed cell foam weather strip to seal the bag. It should be fairly easy to clamp over the seal on the already veneered sides and maybe use the mastic on the top.

Here is a close up of the joint. The edge has been rough trimmed and the end grain disappears when wet. Note the waffle pattern in the epoxy caused by the breather mesh. It should sand off easily. The veneer on the two faces is from the same sheet. There's just a bit more light on the facet on the right.

[dar47]

Great joint, and I hope you smiled after seeing the result.:T

It gives you an idea of what Avalon has to produce over and over again in order to make money. These little details others won't notice or care a bought but it sure makes me happy when I consider the effort, planning and scheming that went into it!

[BobEllis]

Thanks, dar. Yes, there was a big smile even before trimming.

There was only 1/32" or so of overhang on this side. The other side was a bit more, maybe 1/16". That was enough to bend the veneer slightly, but not enough to break it over the edge. That should help give me a bit more to soften the edge before finishing.

Letting the putty harden on exposure to air is making it easier to remove. It will take a few iterations, but a metal putty knife is getting a lot of it fairly quickly after all. Still going to look into altenatives, though.

[Renron]

DAMNNNNNNN!
That's impressive looking. You're doing a fantastic job Bob. It's so pretty!
Perhaps a stupid question, but, have you tried just taping down the edges of the plastic over 3M (for Hank) blue painters tape?, with duct tape over the edge of the plastic and onto the blue painters tape? Anyhoo, 3" wide blue tape / plastic on 1/2 , duct tape over both.
I'm excited at how good that looks Bob, you've got a very good edge. If you take the round shaft of a screwdriver and just break / round over the corner slightly, it will completely disappear.
Ron

[BobEllis]

Great suggestion, Ron. I'll give it a shot. I was thinking it would need more to keep it in place, but thinking about it, the edges didn't seem to move under vacuum. The tricky part will be sealing alongside driver cutouts. Then again, with a 5 SCFM pump I had almost full vacuum with some loud leaks. I may not need perfect sealing...

[TEK]

Looking great Bob!
On my build I first trimmed the corners. Then I rounded them softly with 360 (I think) grid sandpaper. That made the seems totally invisible and it looked like the veneer sheets just merged together.
Applying finish over that and it is practically impossible to see that there is a joint there.

[BobEllis]

Thanks, TEK. This was just a skim with a block plane. Most of the seam that you see is shadow. Look at the bottom of the picture. I cannot feel the edge there. but can up near the top. It dried too quickly to photograph, but a little saliva on the thumb rubbed on the cut veneer edge and it disappears.

KISS Principle revisited. Bagged the top of the speaker with just blue tape holding the bag down. It is a bit leakier than the mastic. The bleeder setting that resulted in 22" Hg vacuum now results in 20". Plenty of adjustment to pull harder if I want to. Sheesh, I could have saved a lot of clean up time! It will save a lot of time on the next facets. Thanks again, Ron!

[Steve Manning]

Looking good Bob .... I have an option other than the mastic, it's designed specifically for vacuum work, though it's rather pricey, but can be used over and over again. I guess the price could be justified if you do a bunch of veneering in the future. http://www.lesker.com/newweb/fluids/...?pgid=apiezonq

[dsrviola]

Some subtle differences in off axis behavior. I actually discussed that with some guys from Avalon at a show once, they dropped some "hints". You may not notice, but I suggest mounting as shown.

You're making some good progress... :T

Thanks for inquiring about this, Bob. I'm running a C79 in my main system, and it never would have occurred to me to try a "vertical" orientation. In my set up the change in orientation wasn't subtle and definitely an improvement.

Congratulations on a great looking build!

Cheers

[TEK]

Thanks for inquiring about this, Bob. I'm running a C79 in my main system, and it never would have occurred to me to try a "vertical" orientation. In my set up the change in orientation wasn't subtle and definitely an improvement.

Congratulations on a great looking build!

Cheers

Hmm, seems like I will habe to turn mine around.
Require a bit more effort than I tought first as they fit a bit to tight...

[BobEllis]

Thanks for inquiring about this, Bob. I'm running a C79 in my main system, and it never would have occurred to me to try a "vertical" orientation. In my set up the change in orientation wasn't subtle and definitely an improvement.

Congratulations on a great looking build!

Cheers

Thank you, and you're welcome. Nice to know that it makes such a difference for you. I'm curious whether I will be able to hear the difference, but I suspect that's an experiment that won't be performed.

Steve, that putty sounds interesting, but somehow I doubt I'll be doing enough veneering to justify that price. Especially since blue tape works well enough for free bagging. I wonder how it compares to blue tack plumber's putty. I do see a vacuum frame/table in my future, though.

[Steve Manning]

Steve, that putty sounds interesting, but somehow I doubt I'll be doing enough veneering to justify that price. Especially since blue tape works well enough for free bagging. I wonder how it compares to blue tack plumber's putty. I do see a vacuum frame/table in my future, though.

Your right you would have to do a lot of veneering to make it pay off. As far as how it compares to plumbers putty ..... as far as use for vacuum related work, no comparison. Apiezon products are one of the best out there for their vacuum greases and related products. We used the stuff that I linked for leak testing of small and large components where you needed a temporary seal. Scoop some out of the can and form it to what ever shape you need, clamp the bits together and start leak testing, at pressure levels orders of magnitude lower than what you are doing for veneer work.

So yep, way over kill but if you can make a case for it, it's the way to go. If blue painters tape works, it's a no brainer ... tape away :T

[Renron]

Bob,
Sometimes I confuse myself, What I meant to say was ;
Put down the blue tape. Then use Duct tape to secure the plastic to the blue tape. Duct tape will hold the plastic better than the blue painters tape. Painters tape won't leave a residue.
I think I got it clear that time...............Deurrrrrr
Ron

[BobEllis]

Thanks, Ron. That's what I understood.

Somewhat surprisingly, I have a tough time getting the blue tape off of the plastic sheet. At least at 3.5 mils the sheet often rips. Holds a vacuum well enough that at least with my higher flow pump that I think duct tape is unnecessary. All in all, it was a great suggestion.

[BobEllis]

Looks like I will get to do some veneering tomorrow and Thursday. Here's hoping that the weather guessers aren't too far off.

In the meantime, Jon was kind enough to share the Vituix Cad files he generated for Ron's build. I swapped the C79 back in and scaled the response down 2 dB to represent my SW223BD02s. This will do until I can get actual measurements. Using that I played around with changing the midrange and tweeter padding resistors to match the reduced woofer sensitivity. I was surprised how much the resistor values interacted with the response.

In the tweeter section swapping the two resistors gives the right attenuation, but the hump from 4500-7500 Hz gets about 1.5 dB bigger. A 2R3 resistor in series seems to be the best way to reduce the level without significantly impacting the response.

Not balancing the changes in the midrange section throws off all sorts of things. There is a bit of baffle step kicking in which increasing just the series resistance reduces, making for a big dip in response and reducing the reverse null.

Overall, several combinations produced flatter upper end response, but were either too attenuated, had bad phase match or required resistor values not available from Madisound in M-Resist. The response below represents the best I think I can do with standard resistor values. I think it matches Jon's original pretty closely just 2 dB down. I plan to buy inexpensive resistors to verify values before committing to the Mundorfs. Comments, suggestions welcome.


Response:



Midrange reversed: The original doesn't have much of a null in the upper crossover. This is almost as much.

[Steve Manning]

Glad you have some good weather up there Bob ..... looking forward to seeing the veneer go on.

[BobEllis]

Thanks, Steve. I'm really getting eager to get cracking on these.

Slight revision - I noticed that the model didn't have the values in for the woofer zoebel. Makes a slight change in woofer response. This revised version matches the correctly simulated Ardent quite closely.

[JonMarsh]

I just spotted that, too. . Also, the LspCAD version shows a deep reverse null on the midrange to tweeter, so that bears some investigation, though with surgery today, and a work conference call coming up in minutes, it won't' likely happen until closer to the weekend. Hang tight...

[JonMarsh]

I find VituixCAD very interesting, but it takes some care to transfer data and networks accurately, and I'm also pretty convinced I need to do some more correlation testing between simulation and measurement; the last several tweaks for the Ardent were done just by measurement, though I did go back and update the schematics.

Now, I've updated the C79 schematic (and the 12MU, but that's for another thread) and put in the driver offset estimates- here are both in phase, and reverse midrange. Note that I've "tweaked" the woofer L1 from 5.6 mH to 4.3 mH, and the C4 tweeter input cap form 4.7uF to 3.9. (these designators are from the "official" schematic, not the VituixCAD component designators. With driver time offsets entered, the reverse null behavior is as expected.








My suggestion is that after I recover from my surgery today, I need to do some correlation testing with regards to these possible updates and versus VituixCAD. Since I'll also likely be switching over to my AudioPrecision analyzer for testing, there will be a lot to track. Probably should do measurements with Fuzzmeasure, too.

For your situation, Bob, I think the right thing to do is model the woofer crossover with gain added, (possible in VituixCAD) and we'll work on bringing up the midrange and tweeter network sensitivity to the highest possible level to use with your other amps. Needless to say, don't buy crossover parts yet!

[BobEllis]

Sheesh, Jon. I guess you're trying to keep your mind off the upcoming plumbing work.

Thanks for looking into this. Ahh, offsets make a difference in the model. I guess those 4.7 µF MR's are going back (Placed the order with Madisound earlier in the week). It makes me feel like I almost understand this stuff after making that same C4 change and considering reducing the same inductor to reduce the excessive baffle step with the lowered sensitivity. Ron and I will be able to claim custom components in our custom designed speakers.

The ultimate goal is to go full passive, and have a design that others can build with the currently available driver. So, let's skip the intermediate semi-active step. I misplaced the SW223BD01 spec sheet, but I think I remember about 2 dB lower sensitivity on the -02. Your model had the woofer scaled +2 dB, so I set it to 0 for my attempts. Now to get the offsets entered and play with it.

[JonMarsh]

For reference, due to value availability, I've ordered 4.0 mH to check. Simulation looks good... 3.9uF on the tweeter.

[JonMarsh]

Sheesh, Jon. I guess you're trying to keep your mind off the upcoming plumbing work.

Thanks for looking into this. Ahh, offsets make a difference in the model. I guess those 4.7 µF MR's are going back (Placed the order with Madisound earlier in the week). It makes me feel like I almost understand this stuff after making that same C4 change and considering reducing the same inductor to reduce the excessive baffle step with the lowered sensitivity.

The ultimate goal is to go full passive, so let's skip the intermediate semi-active step. Ron and I will be able to claim custom components in our custom designed speakers. I misplaced the SW223BD01 spec sheet, but I think I remember about 2 dB lower sensitivity on the -02. Your model had the woofer scaled +2 dB, so I set it to 0 for my attempts. Now to get the offsets entered and play with it.

You should be OK with that approach- 2 dB is the right value, from Wavecor's data sheets. And from T/S data and Unibox simulation. I'm going to be testing all of this soon on my own set- I ordered components today. Note, we're working from simulation here- I really want to see measured stuff too, before anyone goes off the deep end! :W That's why I ordered parts just now...

Yeah, keeps my mind off the upcoming plumbing work, that, and how hungry I am and how good a cheeseburger or a philly cheesesteak would be about now... :B

[Renron]

MMMMMMMMMMMMMM philly cheesesteak

[BobEllis]

Glad to see your procedure went well, Jon.

Veneering on the other hand, not so much. Last Fall I tested a small section vacuum bagging using blue tape to hold the plastic to the surface. It worked well, so I was intending to do the same thing yesterday. Testing the bag I wasn't able to get a decent seal with blue tape, barely getting a couple inches of vacuum on the bag. In retrospect, there were two main reasons why the test was a success and this bag not. The top that I tested on was smooth. There was room to have about 2" of bag outside the breather mesh. The driver cutouts don't allow much room to make a seal on the front. The side has not yet been sanded smooth, it's still a rough surface of epoxy bleed through.

So, I can go back to the mastic. After sitting a couple months the part that remained stuck to the cabinet was fairly stiff and not too hard to remove with a scraper. Not so easy within the first couple weeks. The surfaces need to be sanded, and remnants of the mastic will gum up the sandpaper. I'd prefer not to have to deal with that.

Next test - vacuum bagging the entire speaker. I have a 5 SCFM pump, so it shouldn't take too long to draw down. I have at least a half hour open time with the resin I'm using. I have the vinyl sheet, just need to get some 1x2s to make seam clamps. We'll see if I can get a decent vacuum on a bag that big. Failing that, I will deal with the mastic residue.

I will operate with the vacuum pump outside, the hose coming in a window to the bedroom so the temperature stays up in the decent cure range. (Very understanding girlfriend) An unforeseen problem with this setup is squirrels. Since I removed the screen to allow the hose to come in, several of the neighborhood squirrels have been trying to come in the window. They even seem to know which side of the window opens and are trying to pull it open. I'll have to cut a piece of wood to close the window gap. Hopefully the noise of the pump will keep them away.

[TEK]

An unforeseen problem with this setup is squirrels

I'm amost fallimgmoff the chair here :roflmao: :wtf: :roflmao:
SQUIRRELS - that must for sure be something unforseen - i can understand that you did not forsee that problem...

Oh, almost forgot.
Be carfule vacum-bagging the whole speaker. It might implode, and that would not be any fun...

Especially if a squirrel got in there :roflmao:

[BobEllis]

Considering how that 8 heavy duty Jorgenson bar clamps bowed over a cm when I tightened them to veneer the sides, I am confident that the cabinets will withstand the 10 psi that the vacuum will apply. Assuming the bow meant I was near the rated capacity of 1,000 pounds clamping force each, that's in the neighborhood of 8,000 pounds compressing the cabinets. Ten psi should be only around 6,500 pounds. I will have to make a blank like the grilles to cover the driver holes.

I will check for squirrels first, just in case. :rofl:

[JonMarsh]

You know they're just cute versions of rats that live in trees, right? :W

Our way of dealing with critters like that, and the mole rats we get around here, is Masha.





She's VERY attentive to squirrels, as you can see in this picture. An invaluable asset for keeping the backyard and wood shop safe from the perils of squirrels and other critters (deer and wild turkey are quite common where we live)

[BobEllis]

Beautiful dog, Jon. We have a cat that doesn't understand the concept of catching things. Throw a toy mouse and she taps it on the way by and does a somersault. She will occasionally catch a spider, but that's about it.

[Renron]

I feed the squirrels that eat one bite from each piece of fruit on the trees, pellets.
~900 Fps
My two hunting dogs get really excited and like to play with them.
Agreed, they're Tree Rats! Lost an entire peach tree to them 2 years ago.
At a different house......we seem to move a lot........... A family of tree rats ate an ENTIRE cherry tree's fruit in 3 days, it was ~30' tall.
Ron

[BobEllis]

I caught grief for suggesting they'd be good for paintball target practice.

[BobEllis]

Back at it again, finally. Bagging the whole speaker doesn't work because I can't get the bag sealed fast enough. Back to taping a bag over sections. Started sanding the sides to get a better seal so maybe I can use blue tape or duct tape. Although the plywood end grain sealed in epoxy felt smooth after sanding I still got a bit of telegraphing. My girlfriend didn't notice until I pointed it out, so I'm not going to redo the veneer.

A quick wipe down with a damp rag and I'm excited to finish these.

[flamethrower1]

That looks REALLY sharp