New BassChat 8"Cab design

[Rosie C]

On 18/12/2025 at 10:40, nekomatic said:

Can’t remember exactly but I’m pretty sure I just squeezed mine flat between a couple of pieces of wood and a couple of clamps. 

 

I was thinking along those lines, specifically, sandwich it between two pieces of 18mm ply, then drive my van onto it   

[tauzero]

Do you have to remove the rim from the grill first? It's going to somewhat constrain the flattening if you don't, isn't it?

[rwillett]

9 hours ago, Phil Starr said:

Not very helpfully it took around 15mins, so I'm not sure what is going wrong. I've bashed a lot of metal in the past when I welded my own car bodywork amnd I've dressed a lot of lead when working on the roof so I'm probably fairly efficient. You kind of settle into a nice steady rhythm keeping the work moving. 

 

I'm trying hard to picture what you might be doing. I look not for the high spots but the bits where the metal is most bent. Are you perhaps going for the middle.  The bent bit is around the cicumference around 2-3cm in from the edge (roughly, I dont have it in front of me). Knock these flat and the centre will start to lay flat. Push the middle down without taking out the edges will just mean it springs back.

That's exactly what I am doing. I'm working 2-3cm from outside edge, carefully going round, trying to keep the rubber mallet full face onto the metal. Every so often, I turn the grille over so it's being bashed from both sides.  I've done over an hour on it and it is slightly better, but if I look at it edge on, I can see where the bends were put in 2-3cm from the edge, its not as bad as it started with. 

 

I'm bashing against softwood and I wonder if that's the problem. I'm going to try and find something different to hit against, possible a paving slab or something, cover the slab with material.

 

I can't use plywood and drive the car over it, as I've cut it up for speakers  

 

Rob

[Phil Starr]

1 hour ago, rwillett said:

That's exactly what I am doing. I'm working 2-3cm from outside edge, carefully going round, trying to keep the rubber mallet full face onto the metal. Every so often, I turn the grille over so it's being bashed from both sides.  I've done over an hour on it and it is slightly better, but if I look at it edge on, I can see where the bends were put in 2-3cm from the edge, its not as bad as it started with. 

 

I'm bashing against softwood and I wonder if that's the problem. I'm going to try and find something different to hit against, possible a paving slab or something, cover the slab with material.

 

I can't use plywood and drive the car over it, as I've cut it up for speakers  

 

Rob

You cut up the car! 🤣

 

Try using a bit of timber or hard plastic to concentrate the forces. You can then concentrate on the actually bent bits. 

Edited December 21, 2025 by Phil Starr

[rwillett]

I found a broken paving slab in the back garden and used that. Lo and behold, 15 mins later, it looks a lot better. Lesson here is don't use a softwood base (cut bad puns) to hammer against.

 

Masked the area off and cut it with a Dremel and new cutting discs and the cutting is almost done. I forgot to take into account the rubber edges which hide the raw metal so it's possibly one row of holes too large in each direction. The blue tape is just to hold things together as the rubber edge really wants to curl off

 

 

I'm still thinking about how to fix it to the speaker cab OR to the red corner pieces. Magnets might be the answer here. I have a lot of the strong ones and a simple addition to the red corner pieces might work well. A little bit of velcro through a few holes would allow it to be pulled off easily. With a black baffle board, it might look quite good for me.

Rob

 

[basstone]

3 hours ago, rwillett said:

I found a broken paving slab in the back garden and used that. Lo and behold, 15 mins later, it looks a lot better. Lesson here is don't use a softwood base (cut bad puns) to hammer against.

 

Masked the area off and cut it with a Dremel and new cutting discs and the cutting is almost done. I forgot to take into account the rubber edges which hide the raw metal so it's possibly one row of holes too large in each direction. The blue tape is just to hold things together as the rubber edge really wants to curl off

 

 

I'm still thinking about how to fix it to the speaker cab OR to the red corner pieces. Magnets might be the answer here. I have a lot of the strong ones and a simple addition to the red corner pieces might work well. A little bit of velcro through a few holes would allow it to be pulled off easily. With a black baffle board, it might look quite good for me.

Rob

 

That grille is looking good. One option would be a recessed batten around the whole front of the baffle then screw the grille to that. Also a strip of thin self adhesive foam strip between the grille and the batten helps dampen any tendency to vibrate

[rwillett]

I'm probably going to try to put a small 3d printed block under each corner with quite a strong magnet hidden away. Thats the lime green bit below. The magnet is 0.5mm under the surface of the plastic and so can't be seen. It will have a plug in the back of it and it *may* have some self adhesive foam under that to avoid rattling, I didn't think of the foam so thanks for that. I will also add some foam on the top of the mount between the plastic block and the grille as you suggested. Good ideas those.  The block will be welded to the corner piece (thats the purple bit). Its welded, not glued as the "glue" melts the plastic together and forms a stronger bond than the plastic itself. Might be superglue, might be Floplast. 

 

 

if this doesn;t work, then the recesses battern is plan B

 

Thanks

Rob

[Phil Starr]

It's looking really good Rob, don't do yourself down. There are two issues with the grille. You need to keep it flat and not let it rattle and then it needs to be removable for any maintenance. If the back is stuck on then the speaker hole is the only way back in. It's fairly conventional to use either velcro or the little neo magnets to hold something to the speaker. I'm not sure how well the magnets would work to just hold the grille rigidly in place. If you drop the speakr or somebody kicks it then it will get pushed towards the speaker it is meant to be protecting. I cerainly don't think just magnets in the corners would be enough, and would it rattle at higher sound levels. I'd probably want the grille screwed to a frame which supports the grille along the whole length. Use the magnets to fix the frame to the baffle. Or you could print some sort of peg system to lock the frame to the baffle.

[3below]

Rubber doorstops, they come in a variety of sizes (Google tells me 20mm to 76mm height).  Screw the grille into the frame as per @Phil Starr then some door stops near the middle, black washers and bolts and T nut them in.  The advantage of these is that you can position them to kill any unwanted vibrations in addition to improving the kick resistance.  Strangely in 55+ years of gigging this has never happened, I must be playing the wrong gigs.  Plenty of impacts with doors, furniture, car parts and other kit though.

[rwillett]

I've cut the grill to size and used Gorilla tape on the outside of the frame just to keep it clean tidy.

 

I've printed some riser blocks for the outside of the grill that fit in the corners of the cabinet. The ones in the picture are far too large, but they're to check things out and I'll print some better ones shortly.  These will be glued to the front of the baffle (NoNails) and will have a M3 nut embedded in them. The hole for the nut is aligned to the holes in the grille. On top of the riser block will be some adhesive rubber, 1mm thick), to stop vibrations. More riser blocks may be needed, but the principle is set now. I have the "advantage" of not gigging at the moment, as there's only me and the drummer, so little chance or marauding fans rushing the stage sadly.

 

It's very, very likely that I'll design some M3 handbolts to screw into the riser block. These will probably have the felt washers that are on the guitar strap buttons to further reduce vibration (or may not). I designed a lot of hand bolts for astrophotography, you can check them out here (https://starclamps.com/), these are all parameterised so I have lots of options. I also have some nice brass ones somewhere which might look nice.

 

The red corner pieces have been redesigned so that they don't protrude as far into the baffle area as before, to give the grill some some space.

 

 

The hand bolts should allow the grille to be taken off easily,  

 

Once I've painted the baffle board matt black, most of the riser elements will simply disappear, well that's the idea.

 

Lets see how it works. but I'm off from tomorrow to London so nothing will be progressing.

 

Have a good Xmas all

Rob

[Phil Starr]

happy christmas to you too Rob

[rwillett]

Happy new year all.

 

I originally used black tape around the edges of the grill as there were little sharp bits, I did take the Dremel to them but I then ended up with silver bits on a black grill and I didn't fancy spraying it all to match so put the tape on. To be honest it looked like cr4p and I was never happy with it. The original split tubing around the original circular grill didn't look much better either, so I looked and looked for a better idea and didn't really find anything that I liked, so as per normal, if I can't find it, I look to make my own. 

 

So pulled out Fusion 360 and the digital callipers and tried to see if I design something, I wasn't sure how it would look.

 

This is the Fusion 360 view and this is what it looks like close up.

 

and far away

 

 

I can't make the two long sides in one print as they are 376mm long and the maximum diagonal I can print is around 330mm so its in two pieces. I need to do small adjustments to minimise the gaps but I'll work on that. As its black on a black grille on top of a matt black baffle board, small gaps won't be noticeable. 

 

Somewhat surprisingly its a nice tight fit and the holes I was going to put in the back and put hot glue in aren't needed. 

 

However in the process of printing these, one version went wrong and I managed to destroy the Y-Axis belt on my Prusa MK4, which was a bit of a surprise, as the belts are supposed to be pretty indestructible. I have a box full of spares but guess what I don't have? Oh well, 5M of 6mm GT2 is on the way and should be here tomorrow but I then have to reprint some broken bits and retune the 3D printer. Thankfully I can use the other printer to make the spares (or I hope I can ) 

 

The temperature here is still so cold that I still haven't managed to get the Armacab on the sodding cabinet. We are forecasting snow tomorrow as well, which actually should be warmer than it is today. We got down to -4.5C.

[rwillett]

No snow today and the CFO is heading to York for the day leaving me as something called "the responsible parent". 

 

Given my eldest is severely hungover in a farm near Kirkby Lonsdale and my youngest is off to work, that leaves me and the dog. 

 

I might accidently have to check the cellar and see how warm it is and perhaps check the Armacab paint and see if its frozen, and if not frozen, and all OK, it seems a shame not to test out the paint on some surfaces using the smooth roller for two coats and then the textured roller for the third coat. I will need to build some of jig to hold it but I suspect a coat hanger or two might be just the ticket.

 

Has anybody any experience of masking areas off?

 

Rob 

[RhythmJunky]

2 hours ago, rwillett said:

No snow today and the CFO is heading to York for the day leaving me as something called "the responsible parent". 

 

Given my eldest is severely hungover in a farm near Kirkby Lonsdale and my youngest is off to work, that leaves me and the dog. 

 

I might accidently have to check the cellar and see how warm it is and perhaps check the Armacab paint and see if its frozen, and if not frozen, and all OK, it seems a shame not to test out the paint on some surfaces using the smooth roller for two coats and then the textured roller for the third coat. I will need to build some of jig to hold it but I suspect a coat hanger or two might be just the ticket.

 

Has anybody any experience of masking areas off?

 

Rob 

 

 

I've admired how much use of 3D printing you've used in your build. 

 

I'm sat here reading this in my post Christmas lethargy when my mind started to wander and I ended up thinking if it'd be possible to 3D print an entire cabinet. Or maybe a frame into which you could bond ply or MDF panels for damping. 

 

That'd be an interesting build. Just a thought. 

 

[rwillett]

7 minutes ago, RhythmJunky said:

I've admired how much use of 3D printing you've used in your build. 

 

I'm sat here reading this in my post Christmas lethargy when my mind started to wander and I ended up thinking if it'd be possible to 3D print an entire cabinet. Or maybe a frame into which you could bond ply or MDF panels for damping. 

 

That'd be an interesting build. Just a thought. 

 

@RhythmJunky

 

When you've only got a hammer, everything looks like a nail  But thanks for the kind words.

 

You are not the first person to suggest either a 3d printed cabinet or a frame  or bonding things together. The issue is partly around the maximum size I can print at once, a Prusa MK4 can do circa 250mm by 220mm by 200mm (vertically). Thats fairly standard for most decent printers. Getting larger than this starts to get expensive, so a 350mm x 350mm x 350mm from Prusa is a lot more money. Even that isn't quite big enough for an 8" cab. Going beyond that is even more money. I have looked at 500mm x 500mm x 500mm but they are very big frames, the heated bed is as big as you can go, and even then its patchy. I did enquire with RatRig in Portugal about making a 600x600x100mm printer but they weren't keen at all.

 

Also plastic isn't really a dense material and isn't that suitable for cabinets. I'm definitely at the novice end of the scale here but people want to use MDF and Birch ply or even concrete for the cabinets to avoid ringing. Plastic isn't really suitable, certainly for the bass ports it seems fine and for edges of frames and amp mounts it's OK but I wouldn't think it that good in large scale use.

 

Bonding has been discussed off-line, but I'm not convinced you'd gain anything over plywood. However if somebody has some clever ideas and wants to try, I'm happy to put some time into it. Not sure how much time and effort, but more than nothing and less than an infinite amount  I would suspect a honeycomb in three dimensions might be interesting, but I'm not 100% sure how I'd design it and how to bind it.

Rob

[rwillett]

Decided to bypass test's and simply mask the cabinet up in the kitchen. and paint it. 
 

As the CFO is out and it is still below freezing, I masked the cabinet up before painting. In hindsight this was a mistake, I grossly over estimated how thick the paint covering is. Whilst it's like tar in the tin, it spreads thinly and evenly. A simple mask rather than masking sacrificial parts would have been far quicker but you live and learn. 

 

Managed to get two smooth coats on the cab in the celler. The textured coat is last and I may get that on tonight. 

 

 

The red corners are sacrificial so don't care about them. The real ones will be attached using no nails as I didn't want screws showing. It's still wet in the photo 

 

 

Rob