[musmecca]

Hmmm weird. Here's mine. Smoother finish than brushing.

The difference in the two is the "orange peel" in bassiklee's pic (not his finish), while yours cured glass smooth. Usually this is attributed to surface prep and viscosity of the lac. If the surface isn't lightly sanded (actually 0000 steel wool does the trick) and wiped (tack cloth is fine) it can bead up on the surface instead of flowing. The sprayer improperly set (nozzle clogged, not enough back pressure, or lack not thinned out) will do the same thing. Interesting you said you didn't thin your lac....it usually helps with a smooth sheen. Also, never spay on a humid day or too cold of a day!

 

[Bassiklee]

I'm in north Florida. There's no such thing as a not humid day here. I'm still playing with spraying, but that pic is from a larger manufacturer than me. That, and I was told by another member here that his 64s have that same exact finish.

 

[Bassiklee]

I do sand the surface. No steel wool. I use those scotch bright wheels, flap discs, etc.

If one were to thin lak, what would one use? It's not actually lacquer, they just call it that.

As far as humidity, given that this stuff doesn't dry, it cures, is that part of the equation?

 

[musmecca]

I do sand the surface. No steel wool. I use those scotch bright wheels, flap discs, etc.

If one were to thin lak, what would one use? It's not actually lacquer, they just call it that.

As far as humidity, given that this stuff doesn't dry, it cures, is that part of the equation?

True laquer can be thinned with denatured alcohol....since this stuff is light cured, acetone is the dreve go-to as they even call it "finishing liquid"! And humidity is absolutely part of the equation. As a finish is sprayed, it will trap air under the surface as it cures.....too much humidity in the air and opaque films form and the surface can cure unevenly...again "orange peel". If you have to spray in a humid environment, several lighter coats are the only way.

 

[Bassiklee]

Dreve finishing liquid is for use with their soft vinyl mouth guards. It's not sold for, or recommended for use as a thinner. It's also mostly eucalyptus oil.

 

[mattmatt]

True laquer can be thinned with denatured alcohol....since this stuff is light cured, acetone is the dreve go-to as they even call it "finishing liquid"! And humidity is absolutely part of the equation. As a finish is sprayed, it will trap air under the surface as it cures.....too much humidity in the air and opaque films form and the surface can cure unevenly...again "orange peel". If you have to spray in a humid environment, several lighter coats are the only way.

This shouldn't have orange peel since it doesn't dry out with air. It will still have time to flow and even out once it hit the IEM.

I have thinned and un-thinned sets. Both are great. I actually spray at really really low pressure to avoid over spray and material waste. I think you guys are kind of overthinking this.

This opaque film diffuses over time while you air dry the lak before jumping to light cure.

 

[mattmatt]

Lak is also good to go with spraying out of the box.

 

[ddfcoold]

knowles gv-32830 quad driver with shure se 535 diy shell, knowles green filter




Wasn't sure if I could trust the quality of drivers used with the iems from China on eBay so I decided to see if I could put together my own build with drivers sourced from Mouser.com. With the Westone star silicone tips they sound pretty good. Still burning in. So far sounding brighter and opening up. The highs sounded really muffled on initial listening session. I also removed the tape that covers the two vent holes on the drivers. Low end seems to have good extension but still doesn't have the impact/pressure that dynamic drivers have. Overall very simple build. Just wire up everything. Epoxy driver to the opening inside shell. Careful not to use too much epoxy. Excess can get into the driver opening. Making sure also to get good seal around edges where driver meets with opening to exit nozzle. Not bad for approx $150 in parts.

How does removing the seals affect the sound?

 

[Bassiklee]

Adds some level to the HODVTEC

 

[musmecca]

Just recently had a few shells get very brittle and literally fall apart. Using Dreve clear, but this time added a little mica powder and some of the resin dye available from resin obsessions. I made sure I thoroughly mixed, waited for the air to come out, then poured. I increased cure time up to 4:30 and had a great shell...strong with about 2mm wall thickness. After a few weeks, both sides just literally fell apart.....thoughts guys?

 

[Bassiklee]

Maybe Overcured to the point where they got brittle??

 

[dhruvmeena96]

Just recently had a few shells get very brittle and literally fall apart. Using Dreve clear, but this time added a little mica powder and some of the resin dye available from resin obsessions. I made sure I thoroughly mixed, waited for the air to come out, then poured. I increased cure time up to 4:30 and had a great shell...strong with about 2mm wall thickness. After a few weeks, both sides just literally fell apart.....thoughts guys?

Ohhhhh
That hurts a lot mate

 

[musmecca]

Ohhhhh
That hurts a lot mate

And it should hurt you...it was your finale 3 build! Arghhh...!

 

[Wgibson]

Howdy, I've been lurking and have a few questions that I couldn't answer by searching (here, or google.)

Background: mechanical engineer, mid 30's, decent grasp on electrical, got really into cheap chifi iems during the pandemic, then started in on basic mods (mmcx conversions) and in the process gathering tools/components, and working on my soldering skills. So now I have a full fledged aliexpress addiction, and I'm sitting here with some drivers and shells in the mail for diy iem projects.

Not asking for anyone to hold my hand, but pointing me in the right direction on the electrical side especially is greatly appreciated. I think I have, or can obtain, a decent handle on the physical/acoustic damping. But I am also smart enough to know what I don't know, about all the other aspects of this type of project.

Anyway, now for the electrical questions, let's say all are general/hypothetical for now.

1) DIY hybrid iem, 1DD and 1BA in parallel, I assume you can use a low pass inductor on the DD without negative consequence to the BA, true or false? Or do I need an RC low pass on the DD instead? I am generally familiar with the BA inductance and saturation, at least enough to know there are issues and trying to low pass a BA with an inductor is a no-no.

2) Using a single capacitor high pass filter on 2 BAs in parallel, any pitfalls?

3) What is everyone using for crossover design? Downloaded Xsim but can't find any of the common BA driver files (FRD / ZMA files)

4) Not strictly electrical, but has anyone used a knowles SR-32453 for super high frequencies? The graph looks good over 10k, but what really struck me was the fairly stable impedance in that area, not a super sharp increase like you see with most other BAs. At face value it looks way better than say a 30095, which is a very common solution...

5) OK so I lied about these being only electrical questions. Thoughts on a 4x RAF or RAB in series with 2 of the dampers closed, 2 open? Would your thoughts change if there was a dip switch with the option to also put them in 2x2 series/parallel configuration?

6) I have a dayton imm6 set up and can make some reasonable looking graphs for iem comparisons, but I know I still have a lot of work to do on measurements.

7) Yes I know it seems like I'm getting in way over my head. I spent some "real money" on a pair of 10mm planar drivers, so between tweaking those and trying to fix some things I don't like about a few cheaper chifi hybrids, I promise I'll take it slow and do some work on the phsyical/acoustic tuning side. I'm also fine with a guess and check method for more complex multi driver stuff, anything to keep me occupied. Who knows, I might get lucky.

Thanks in advance for any input, I have pretty thick skin so as long as there is a shred of helpful information, just let me know what you really think.

 

[mattmatt]

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