Bass cab build BFM omni top 12.

[billynoband]

I purchased plans for the DR250,Tuba24 and I think the omni top 12 from Bill Fitzmaurice some years ago. I say think as I only have pages 5 to 16 left of the omni top plans but I think all the info is there. I built the DR250 and Tuba24 some years ago but never used them properly before selling. So with 32 quid of ply from Wicks and 8 quid of glue, a handsaw, nails, hammer , an old HH dual purpose speaker for the time being , here goes a omni top 12.

Edited April 29, 2018 by billynoband

[bertbass]

You might find pages 17, 18 and 19 handy.

[billynoband]

And I can't work my new phone to upload pics. I am however a child of the 60s so I can use a handsaw properly at least , to justify these excellent and easy to build plans.

 

Edited April 29, 2018 by billynoband

[billynoband]

[billynoband]

[billynoband]

One thing about this build. The horn sides have a forty and fifty degree angle cut. It's critical to get these right. The rest is simple.

[billynoband]

[billynoband]

[SpondonBassed]

On 29/04/2018 at 18:25, billynoband said:

And I can't work my new phone to upload pics. I am however a child of the 60s so I can use a handsaw properly at least , to justify these excellent and easy to build plans.

 

If it was me, I'd use the handsaw to open the phone so I could shake the photos loose and send them surface mail.

Glad you got topside of it in the end.

[SpondonBassed]

I like the provision of a mattress in the workshop.

You are either:

• obsessively dedicated to the project
• barred from bringing sawdust to bed with you

 

 

 

 

Heeheehee

[billynoband]

Looks loud and deep so far.

[billynoband]

It's in a useable state now. There seems much more volume at number 2 and not dead anymore with this speaker now in its new home with the same 60 watt HH amp as before. It sounds very colourful almost too much , musical and has more bass like a very expensive 12" speaker does. There are no unwanted noises. I know it's a general purpose old HH 100 watt 4 ohm cone I am using for impatient testing but I am convinced they were good quality originally. Strangely it is not breaking up using the gain knob at low volume anymore like in its old home it just adds more volume. Would be interesting to hear it at decent levels but it's bank holiday Monday. Good fun though.

[Si600]

What's the technical thinking behind these enclosures, what does having the speaker obscured behind a slit between two angled sides do?

[RichardH]

It's a horn.

[Si600]

Thank you.

[billynoband]

The speaker is mounted back a touch . I presume a small gap forces the sound out quicker and the flared horn disperses the sound better.

[billynoband]

If anyone wants this cab for free you can come and fetch it from Kettering today nn15. tomorrow It's in the skip like a lot of my families stuff will be. Tuff luv today. It's still as is in the photos, unfinished but works. I am not playing at the moment and am clearing the garage out. Phil.

[Skinny]

I didn't bin it in the end. Four years later I get around to buying some blackboard paint and fitting a vintage Fane driver instead of the excellent HH which was a guitar thingy unit. I shall be fitting the recommended driver if I decide to use the cab on stage. You would of thought lock down would of given me time but as I work for the national grid it didn't happen. I changed my member name as I messed up signing in so often too.

Edited June 12, 2022 by Skinny
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