EnABL Processes

[Bas Horneman]

I used this...I suppose ANY acrylic paint will work...and ANY modelstore should have acrylic paint.


Cost me all of € 1.75

[BudP]

Wow, leave you guys alone for a day and look what happens....

soongsc,

Yes, by all means use an acrylic paint so that you can experiment. For small diameter metal domes I use technical drawing pens with a 50% water cut acrylic paint so that the material will flow properly. The blocks will only be as thick, in width of strip, as the pen point. As you get below 20 mm of block ring diameter, the blocks change to dots, work just as well and do not block the entire space alloted to them. Working with Titanium, the blocks retain this character, that of being smaller than their alloted space, right out to many 100's of mm of block ring diameter. So the Reynolds numbers do control how much area is swept by a block. Thickness seems less important than interruption and pattern, regardless of surface and material.

Bud

Dan,

I apologize. I remember your question and I did think on it for a while and those thoughts did actually cause me to choose a particular path on the upcoming Lowther treatment. The Mamboni triangles are currently being put on with a PVA glue. This material, for what ever reasons, does not act as a damping agent. Instead it acts as an enhancement to boundary layer activities, on soft surface paper. It is pervasive by the way, if you put it over an EnABL pattern it swamps the patterns effectiveness, but, putting the EnABL pattern over PVA works quite well. It does requires a full, single , cost of Micro Gloss.

If the glue on the felt is a relatively stiff material I suspect it would work fine, but, I have no experience with any of the Mamboni processes yet. As for the tape process I see no reason why it would not work, at least initially. You would need to have a flattened conic section with pattern printed on it to get curved blocks from. Straight line blocks will probably work, but, again I have no experience here. From other tape fiasco's I will warn you to seal the edges with the Micro Gloss to keep the adhesive from oxidizing and allowing the tape to peel. Most tapes are about .003 thick so that may or may not be a problem and the Micro Gloss will help with the edge transition. I think you should try it and report back. I will make a conic section for you, to your measurements. These do not ever fit on first pass so you will need some soft ware to manipulate the images with and if you have Corel Draw that will be perfect.

Bud

Bas,

Welcome and nice workmanship. What did you use as an applicator? Were you able to get 36 sets of blocks? Should you wish to experiment, using drastically fewer blocks will shelve high frequencies, beyond the pattern, pretty severely. I use a six block pattern, around a central dot, on domes, to kill the typical beaming from the tip of the dome. I then place a drop of PVA right in the center, using the barrel of a round toothpick, that is cut in half, for an applicator. Then one coat of Micro Gloss over than whole pattern. The PVA controls the rest of the domes emitted wave front shape, much as a phase plug will, only better and without any side effects.

I do occasionally re coat a block that seems to sink more than the rest. Often it is best to wait till all have dried to a tacky surface, before doing this. Be careful in your choice of coatings to go over the blocks, If it is not as hard or harder than the Micro Gloss you can end up with a cone slow enough to actually alter the pitch of the sound. I discovered this on a guitar speaker I treated, with a regular spar varnish overcoat. Also, flat paints seem to work best due to the amount of material suspended in the paint, as Moray James has suggested.

Thanks C2C, as usual, the right stuff, just in time.

Bud

[soongsc]

Originally posted by BudP
Wow, leave you guys alone for a day and look what happens....

soongsc,

Yes, by all means use an acrylic paint so that you can experiment. For small diameter metal domes I use technical drawing pens with a 50% water cut acrylic paint so that the material will flow properly. The blocks will only be as thick, in width of strip, as the pen point. As you get below 20 mm of block ring diameter, the blocks change to dots, work just as well and do not block the entire space alloted to them. Working with Titanium, the blocks retain this character, that of being smaller than their alloted space, right out to many 100's of mm of block ring diameter. So the Reynolds numbers do control how much area is swept by a block. Thickness seems less important than interruption and pattern, regardless of surface and material.

Bud

I think the concept is beginning to make sense. Since the wave travelling across the cone is at sound speed, small disruption should cause separation. But it also seems sticking clean edged cutouts should be more effective than paint. Also we would probably need more separation for a convexed surround than a concaved surround.

[johninCR]

Now that I understand the suspended solids info a little better, maybe it's time to mix some diamond dust in the micro scale and replace C37 as the top dog price wise.

[c2cthomas]

Rhinestones would work well for here in the Nashville area!!

[dlneubec]

Originally posted by BudP
Dan,

I apologize. I remember your question and I did think on it for a while and those thoughts did actually cause me to choose a particular path on the upcoming Lowther treatment. The Mamboni triangles are currently being put on with a PVA glue. This material, for what ever reasons, does not act as a damping agent. Instead it acts as an enhancement to boundary layer activities, on soft surface paper. It is pervasive by the way, if you put it over an EnABL pattern it swamps the patterns effectiveness, but, putting the EnABL pattern over PVA works quite well. It does requires a full, single , cost of Micro Gloss.

If the glue on the felt is a relatively stiff material I suspect it would work fine, but, I have no experience with any of the Mamboni processes yet. As for the tape process I see no reason why it would not work, at least initially. You would need to have a flattened conic section with pattern printed on it to get curved blocks from. Straight line blocks will probably work, but, again I have no experience here. From other tape fiasco's I will warn you to seal the edges with the Micro Gloss to keep the adhesive from oxidizing and allowing the tape to peel. Most tapes are about .003 thick so that may or may not be a problem and the Micro Gloss will help with the edge transition. I think you should try it and report back. I will make a conic section for you, to your measurements. These do not ever fit on first pass so you will need some soft ware to manipulate the images with and if you have Corel Draw that will be perfect.

Bud

Bud,

I downloaded your pattern file you originally posted and simply messed with the printing percentage until I got a conic size that matched the dia of my woofers, right at the inside edge of the surround. The pattern was, of course, sized right along with it. Is this an appropriate method? If so, I can print the pattern on adhesive back mylar and simply cut the 36 pairs out from that. Does that make sense?

I will have to read back to see what the process is and when to apply the Micro Gloss. The driver is an aluminum cone, very thin and does have a satiny black, smooth, non-sticky coating, though I have no idea what it is. Would the pattern alone possibly suffice or is the Micro gloss layer an absolute?

[swak]

I have a pair of 15" JBL woofers on which the Manboni/enABL treatment could be beneficial. Here are the response curves: http://audioheritage.org/vbulletin/s...ad.php?t=10655

There is a huge peak at around 1.7Khz and I wonder how the treatments discussed work there. I am inclined to begin with the Mamboni treatment on the back.

I have a tube of JBL "Moyen RS-3087 Cement" glue (which is the one used by jbl to construct the drivers). Would it work well with the mamboni treatment or what sort of PVA glue should I get. I see the glue is applied in such a way that it extends toward the center of the cones beyond the felt triangles: is this done on purpose?

(Sorry if this have been covered before, I have read a lot of the two or three treads where these things has been considered, but found few comments about the particular glues (other than the one from Partsexpress) and felts being used or that are appropriate. As I am in Germany I would like to source everything locally (many Train-model fans here, so I guess sourcing the materials for the enABL should not be that difficult.)

[soongsc]

Bud,

I just remembered that it's possible to make pattern transfers the same way as they do with some of those thin shiny labels. Pretty much the same way we do our labels. I think it will work for metal and pp cones where removing the sticky stuff from the transfer is easier.

[soongsc]

Originally posted by swak
I have a pair of 15" JBL woofers on which the Manboni/enABL treatment could be beneficial. Here are the response curves: http://audioheritage.org/vbulletin/s...ad.php?t=10655

There is a huge peak at around 1.7Khz and I wonder how the treatments discussed work there. I am inclined to begin with the Mamboni treatment on the back.

....

This is a cone breakup mode which I doubt can be solved by this process. With paper cone

[BudP]

Dan,

That is the correct approach. You do want a about a block width of space between the lower edge of the surround and the top edge of the top row of blocks.

I would listen to the cone, if possible, before applying the Micro Gloss. The decision point here, for me, is what amount of "constraint" or "repression" does the sound now have. If it sounds as if the energy is just not getting off of the cone then coat the area of pattern blocks on both the cone and blocks. I am fairly sure this will be needed, but if I were doing the work, I would proceed in this fashion.

Sorry to use such spongy terms but audio sound is not like snow sound and the Aleut people, where every format of snow is carefully described and everyone has the same information for qualitative differences. After just a short exposure to this treatment process you will know exactly what I mean with these words.

Also, you might try hooking the driver up and playing some soft music through it, to gain some experience with what changes occur as you near completion of the pattern rows.

Don't ignore the inner row and dome. Go back to page 8 of this thread and look for post #78 where I posted treatment done by ultrakaz on a Yamaha speaker.

Bud