New BassChat 8"Cab design

[tauzero]

1 hour ago, rwillett said:

No mounting holes? Sides, back, top?

 

No. I'm not that bothered, just got to remember to put the handle on the side.

 

12 battens cut out and drilled, next is the circular saw. Hopefully I will still be decidigital following this operation.

[Rosie C]

1 hour ago, rwillett said:

Rosie,

 

Flip the Elf over and see if there are mounting screw holes on the bottom. The manual may say something about it, another clue is if TC offers a mounting bracket for the Elf.

 

Ah, I've not bought it yet. I've found the manual but it gives no clues, and I've not found any photos of the underside on line!

[tauzero]

8 minutes ago, Rosie C said:

 

Ah, I've not bought it yet. I've found the manual but it gives no clues, and I've not found any photos of the underside on line!

 

 

Screw-on feet, so that's a possible.

[rwillett]

Something like this? I have no idea about the dimensions, but this slips under the screw in feet. The screw in feet lock this down, no changes to the Elf, no warranty issues.  It then slides into the base I designed for the Gnome. The height of it should be less than the height of the rubber feet.

 

 

This is not to scale, it's 5 mins work in Fusion 360. I thought about it walking the dog. The principle would work for anything with screw in feet. They can be staggered or in odd places.

 

Rob

[Stub Mandrel]

13 hours ago, tauzero said:

 

 

Screw-on feet, so that's a possible.

 

Steel case. The obvious solution is two strips with big neodymium magnets set in them.

[Phil Starr]

2 hours ago, Stub Mandrel said:

 

Steel case. The obvious solution is two strips with big neodymium magnets set in them.

They probably wouldn't need to be that big either. Strangely I nearly ordered some last night to hold on a grille I'm fitting to my BC108 I'd just ordered a couple of bits from AliExpress including some threaded inserts for mounting the speakers and noticed the said magnets in the corner of the screen at a good price, but just as I clicked so too late.

 

I'm sitting here with my Gnome in front of me, as you can see the feet are naturally dovetailed so flipping them over would be possible. Alternatively a bigger bolt head or a steel washer would bring the screw head up to a fraction below the feet so that a set of four neo button magnets would engae with the bolt head and it would stop an amp sliding around. Another option would be to embed a magnet into the feet to engage with magents embedded in the cab.-

 

[Phil Starr]

And just in case you don't think a magnet can't hold a Gnome captive. This is my magnetic tray doing the lifting

 

[Stub Mandrel]

2 hours ago, Phil Starr said:

They probably wouldn't need to be that big either. Strangely I nearly ordered some last night to hold on a grille I'm fitting to my BC108 I'd just ordered a couple of bits from AliExpress including some threaded inserts for mounting the speakers and noticed the said magnets in the corner of the screen at a good price, but just as I clicked so too late.

 

I'm sitting here with my Gnome in front of me, as you can see the feet are naturally dovetailed so flipping them over would be possible. Alternatively a bigger bolt head or a steel washer would bring the screw head up to a fraction below the feet so that a set of four neo button magnets would engae with the bolt head and it would stop an amp sliding around. Another option would be to embed a magnet into the feet to engage with magents embedded in the cab.-

 

 

On the battery hatch for my sire, I removed it, screwed the screws back in, flush. Then I drilled out the holes in the hatch a little and superglued in small magnets.

[Phil Starr]

I just saw this post in another thread, I put in approximate dimensions of my cab and they quoted £55 for a basic level plywood cut to size. A 1220x604mm sheet of ply from wickes is £15 so you could maybe shop around for cheaper but cut to size is clearly available. This firm offer a 33% discount for 'trade' so it mught be worth someone trying to input their band as a business  

 

For information only though, I've never tried this firm

 

 

[Stub Mandrel]

I've never had any problems with sheet cut to size at B&Q. First half dozen or so cuts are free rest about 50p each?

[Phil Starr]

2 hours ago, Stub Mandrel said:

I've never had any problems with sheet cut to size at B&Q. First half dozen or so cuts are free rest about 50p each?

i've had good experiences with B&Q too and once they start I've never been charged any extra.

[rwillett]

First dumb questions of the day...

 

Managed to one of my plywood pieces cut down to what appears to be the right sizes. I got a Makita guide rail and adaptor for the circular saw. Also an 80 tooth 190mm blade. Suddenly I have straight and clean cuts. Wow. Why have I never done this before. 

 

Anyway, I have the batons. Nobody had 20mm at all only 25mm so have had to use that. 

 

I have plywood for four cabinets now, one will be a spray booth fan holder so one piece of plywood is for cockups. 

 

Also Blue Arran have sent their stuff so I have two speakers to install and stuff for wiring. 

 

Q1 does using 25mm batterns make a massive difference to the sound due to the internal volume changing? I know I'll have to adjust the batten sizes to make them fit but I can do that. 

 

Q2 should I glue and screw the batterns OR just screw OR just glue? People seem to have done all of them. 

 

Q3 I have all the bits for two separate 8" cabs and was thinking I could connect the two cabs together via some magic with the dual connector speakon connectors plates. So two cabs presenting 4 Ohms to the Gnome. Of course I never checked I could do this and arrogantly assumed I'd find a way. Is this feasible, sensible and doable?

 

 

 

 

 

Edited 16 hours ago by rwillett

[RhythmJunky]

8 minutes ago, rwillett said:

First dumb questions of the day...

 

Managed to one of my plywood pieces cut down to what appears to be the right sizes. I got a Makita guide rail and adaptor for the circular saw. Also an 80 tooth 190mm blade. Suddenly I have straight and clean cuts. Wow. Why have I never done this before. 

 

Anyway, I have the batons. Nobody had 20mm at all only 25mm so have had to use that. 

 

I have plywood for four cabinets now, one will be a spray booth fan holder so one piece of plywood is for cockups. 

 

Also Blue Arran have sent their stuff so I have two speakers to install and stuff for wiring. 

 

Q1 does using 25mm batterns make a massive difference to the sound due to the internal volume changing? I know I'll have to adjust the batten sizes to make them fit but I can do that. 

 

Q2 should I glue and screw the batterns OR just screw OR just glue? People seem to have done all of them. 

 

Q3 I have all the bits for two separate 8" cabs and was thinking I could connect the two cabs together via some magic with the dual connector speakon connectors plates. So two cabs presenting 4 Ohms to the Gnome. Of course I never checked I could do this and arrogantly assumed I'd find a way. Is this feasible, sensible and doable?

 

 

 

 

 

I'm not sure that I'm qualified to give you full advice on this, but I'll go ahead anyway 😆 .

 

1) The difference in volume between a 300mm length of 25mm by 25mm baton and 20mm by 20mm is 0.0675 litres, so if you multiply this by the length of the baton you're using it'll tell you the difference in volume. Personally I can't see it making a massive difference, but I expect somebody will be along soon who has better knowledge. What's the total length of baton you'll be using? (I can't remember the size of the cab). 

 

2) I'd glue and screw. 

 

3) yes, that's easy and feasible. You just need to wire the plates so that plugging in the second speaker connects it in parallel to the first by shorting between the positive of the first post to the positive of the second and the same for the negatives. You'll need to make sure that you never try and connect two amps to the same cab, or to the two connected cabs. I've been thinking about doing the same if I ever get around to building this cab, but would also quite like it to be configurable to run in stereo for my keyboard. Hmmm,maybe I need a four box solution 😆, but then again I already have an Ashdown 4x8.

[rwillett]

Better qualified than me...

 

There is approx 310cm of baton. 

 

Total volume of 2.0cm x 2.0cm x 310cm = 1,240cm^3

 

Total volume of 2.5cm x 2.5cm x 310cm = 1,937.5cm^3

 

Approx total interior volume of cab = 40x30x27.5 = 33,120cm^3. I know it's slightly less as I should take into account the overlap of pieces but I've only got an iPhone with me and it's hard to keep track from the PDF. 

 

So (1937-1240)/33120 = approx 2% change. 

 

No idea if a significant change. Doesn't sound like it but what do I know. 

 

Rob 

Edited 15 hours ago by rwillett

[rwillett]

44 minutes ago, RhythmJunky said:

You just need to wire the plates so that plugging in the second speaker connects it in parallel to the first by shorting between the positive of the first post to the positive of the second and the same for the negatives.

 

Strange usage of the word "just" I hadn't heard before 😊

[basstone]

Is the 25mm batten a finished size. Usually planed timber is smaller than the stated size! The stated size is what the rough timber started as before planing.. I hope that makes sense. Of course the same would apply to the 20mm batten unless the specification uses actual finished sizes!

 

I would also agree with glueing as well as screwing as you get solid contact along the whole length of the batten.

 

most commercial speaker cabs have 2 connectors wired in parallel ( +/- 1s connected together) specifically for adding a second cab. 

[rwillett]

14 minutes ago, basstone said:

Is the 25mm batten a finished size. Usually planed timber is smaller than the stated size! The stated size is what the rough timber started as before planing.. I hope that makes sense. Of course the same would apply to the 20mm batten unless the specification uses actual finished sizes!

 

I would also agree with glueing as well as screwing as you get solid contact along the whole length of the batten.

 

most commercial speaker cabs have 2 connectors wired in parallel ( +/- 1s connected together) specifically for adding a second cab. 

The battern is 25mm, the one time I wanted to be sold short, I don't get it 😩. 

 

I have a little pack of speakon pieces, plates and pcb's from Blue Aran so will look at that. 

 

Today's activity is cutting round holes in plywood and screwing batterns down. I also need to make a jig for the speakon plate. That looks a little difficult. 

[Obrienp]

20 hours ago, Phil Starr said:

i've had good experiences with B&Q too and once they start I've never been charged any extra.

I wish our local B&Q did that! It’s an hour’s drive into Norwich for one that does.

[RhythmJunky]

1 hour ago, rwillett said:

 

Strange usage of the word "just" I hadn't heard before 😊

If you're not sure how to do this, then post a photo of the back of the plates showing the connectors and I'll try and help. Can you solder ? 

[rwillett]

9 minutes ago, RhythmJunky said:

If you're not sure how to do this, then post a photo of the back of the plates showing the connectors and I'll try and help. Can you solder ? 

Thanks for the offer of help. I will take it up. If it's clear enough for me I should be able to document it for other people. 

 

I can solder so that's not an issue. 

 

Today's activities are dog walking and cutting holes without damaging myself and ruining the already cut plywood. 

[Phil Starr]

OK first of all I wasn't sure which batten to specify, conventionally timber is specified by its sawn dimensions and then planed down afterwards. Years ago this was only partially mechanised so wood was planed until it was smooth with variable amounts removed ending up with slighlty different thicknesses.  In the end I used the 22mm that B&Q specified for their batten. I don't think the extra volume will be significant.

 

Screw and glue, The whole design of the 'easy build' cab is based upon the ease of forming really strong 90deg joints without needing clamping. The screws hold everything in place and put pressure on the joints until the glue sets. The glue is what gives the cab it's final strength (it's stronger than the wood) and it also seals the joint so it is completely airtight. One option is to assemble the cab 'dry' with just the screws to check everything fits properly. You can teh take it apart and assemble it with the glue. I'll explain the gluing procedure later today. 

 

Using a 2x8 with the speakers in a separate cab is just like combining any two 8ohm cabs and I always install twin sockets on my cabs so that I can do this. If you wanted to build a 2x8 in a single box it needs to be double the size but crucially the ports need to be changed to keep the larger space tuned to the same freequency..

 

I'll be back later today with some links and advice on the build.

[rwillett]

Thanks all for information 

[RhythmJunky]

This explains it pretty well.

 

The diagram half a dozen posts down on this thread explains it pretty well. 

[Phil Starr]

3 hours ago, rwillett said:

First dumb questions of the day...

 

Managed to one of my plywood pieces cut down to what appears to be the right sizes. I got a Makita guide rail and adaptor for the circular saw. Also an 80 tooth 190mm blade. Suddenly I have straight and clean cuts. Wow. Why have I never done this before. 

 

Anyway, I have the batons. Nobody had 20mm at all only 25mm so have had to use that. 

 

I have plywood for four cabinets now, one will be a spray booth fan holder so one piece of plywood is for cockups. 

 

Also Blue Arran have sent their stuff so I have two speakers to install and stuff for wiring. 

 

Q1 does using 25mm batterns make a massive difference to the sound due to the internal volume changing? I know I'll have to adjust the batten sizes to make them fit but I can do that. 

 

Q2 should I glue and screw the batterns OR just screw OR just glue? People seem to have done all of them. 

 

Q3 I have all the bits for two separate 8" cabs and was thinking I could connect the two cabs together via some magic with the dual connector speakon connectors plates. So two cabs presenting 4 Ohms to the Gnome. Of course I never checked I could do this and arrogantly assumed I'd find a way. Is this feasible, sensible and doable?

 

 

 

 

 

Hi Rob, looks like you are cracking on. I don't know whether you have seen this. It's a video of me assembling an 'easy build cab' live at one of the SW bass bashes a few years back. The technique is the same ror all the 'easy builds'. The size changes but the procedure always remains the same

 

 

[Rosie C]

2 hours ago, Phil Starr said:

Using a 2x8 with the speakers in a separate cab is just like combining any two 8ohm cabs and I always install twin sockets on my cabs so that I can do this. If you wanted to build a 2x8 in a single box it needs to be double the size but crucially the ports need to be changed to keep the larger space tuned to the same freequency..

 

Interesting. When I first started thinking of this build I was thinking of having it sloped, 'monitor speaker' style. That would work even better with a 2x8.

 

2 hours ago, rwillett said:

Today's activities are dog walking and cutting holes without damaging myself and ruining the already cut plywood. 

 

Keep safe! It does seem to me that there's a certain edginess in us setting to with power tools to make speakers, when fingers are so vital to our playing!   

I used to have a classic car that I worked on myself. My old piano teacher used to say in a deadpan style that one missing finger she could help me work around, 2 and my piano playing would be seriously affected! I was never how much she was joking.