Diy Speaker cabinet ideas/help

[Knipester]

I’ve just picked up a pair of Fostex ff8k full range speakers as I’ve been fancying build some cabinets. 
 

the woodworking isn’t a problem (I’m looking forward to that bit) but designing a cabinet that’s going to sound half decent is my problem. 
 

What I do know is that I plan to use birch plywood to construct them, ideally they’ll be bookshelf sized, I’m thinking I’d like to use a sloped back diamond design aka Avalon, but open to other ideas. 
 

Any advise would be much appreciated.

 

[JamieMcC]

Have a look at the planet 10 fonken designs I have some Fostex fx120 full range drivers in fonken enclosures and the sound wonderful. 

http://planet10-hifi.com/fonken.html

Also if you have not done so look up your drivers at https://fostexinternational.com there should be some enclosure recommendation with plans and dimensions etc.

 

[Knipester]

Have a look at the planet 10 fonken designs I have some Fostex fx120 full range drivers in fonken enclosures and the sound wonderful. 

http://planet10-hifi.com/fonken.html

Also if you have not done so look up your drivers at https://fostexinternational.com there should be some enclosure recommendation with plans and dimensions etc.

Thanks Jamie. I’ve found the ff8k spec sheet under their discontinued Items page but there’s no recommended enclosures. Should I be looking in a different place? 
 

the planet 10 fonken design looks very easy to follow so thanks for that as a back up. I’d really like  to use a sloped back design so changing the baffle plates angle to this design would i suspect impact its design/performance?

how do you work out the cabinet volume required and is this dependent on the shape of the cabinet?

 

[Tony_J]

Paul -

If you can find out the T/S parameters for the drivers, you will be able to model its behaviour in different cabinets using one of the free modelling apps that are out there. The one I am currently using is called Basta - 

http://www.tolvan.com/index.php?page=/basta/basta.php

For a given type of cab (sealed box, ported...etc) it will make suggestions as to the appropriate cabinet volume - you can then play with dimensions, port sizes etc. and see what effect they have. Once you get the hang of it, pretty straightforward.

 

[Knipester]

Paul -

If you can find out the T/S parameters for the drivers, you will be able to model its behaviour in different cabinets using one of the free modelling apps that are out there. The one I am currently using is called Basta - 

http://www.tolvan.com/index.php?page=/basta/basta.php

For a given type of cab (sealed box, ported...etc) it will make suggestions as to the appropriate cabinet volume - you can then play with dimensions, port sizes etc. and see what effect they have. Once you get the hang of it, pretty straightforward.

Tony... thank you I’ve just looked at the link and my heads exploded

 

[Tony_J]

Tony... thank you I’ve just looked at the link and my heads exploded

Paul - there are no free lunches... 

 

[Knipester]

Maybe I’ll just guess and fall lucky?

 

[Tony_J]

Maybe!

 

[JamieMcC]

Found a spec sheet on Madisound that gives some sizes dimension for the ff8k

https://www.madisoundspeakerstore.com/approx-3-fullrange/fostex-ff85wk-3-full-range/

Here is are a couple of pics of a past project also using 3" drivers they might help with ideas. I made them for my daughters room/computer desk. For a small desk top speaker the nearfield experience really has to be heard to be believed.

Drivers are 3" Scanspeak Discovery 10F/8414G10 full range drivers in Micro Fonken enclosure made out of Ikea bamboo chopping boards. These have an internal volume of 2 litres.  The ff8k looks like it needs 3 litres from the link above.

 

 

[Knipester]

Found a spec sheet on Madisound that gives some sizes dimension for the ff8k

https://www.madisoundspeakerstore.com/approx-3-fullrange/fostex-ff85wk-3-full-range/

Here is are a couple of pics of a past project also using 3" drivers they might help with ideas. I made them for my daughters room/computer desk. For a small desk top speaker the nearfield experience really has to be heard to be believed.

Drivers are 3" Scanspeak Discovery 10F/8414G10 full range drivers in Micro Fonken enclosure made out of Ikea bamboo chopping boards. These have an internal volume of 2 litres.  The ff8k looks like it needs 3 litres from the link above.

 

They look superb, never thought of using IKEA chopping boards as a construction material. 
 

If you could confirm the dimensions that would be great, also what configuration is inside? Front ported is a must for me so that’s a  

 

[JamieMcC]

Nice thing with the chopping boards is there is no where near the finishing work required compared to a painted finish

I liked the look of some of the bamboo finished https://www.blumensteinaudio.com/all-products speakers the chopping boards made it easy.

They are the micro UFomkens the plans are in the link I posted earlier I think you need slightly larger enclosures for your ff8k.

Give Dave a email at Planet10 he is a really nice and knowledgeable guy see what one of his enclosures he recommends for the Fostex ff8k. You can also contact him via the Diyaudio forum.

 

[Knipester]

I think having returned to their website the obvious design is the ff85k ufonken ov9.

http://p10hifi.net/tlinespeakers/FAL/box-plans/microFonken-0v9-map.pdf

do you think I’d knack the design up by having a thicker baffle so It can be chamfered aka Avalon design?

 

[bobovox]

Jamie, great looking speakers. I’ve long been thinking about a full range project with the 10f units. Did you incorporate a shelving filter to deal with the baffle-step? For example, an inductor with a parallel resistor?

 

[JamieMcC]

Jamie, great looking speakers. I’ve long been thinking about a full range project with the 10f units. Did you incorporate a shelving filter to deal with the baffle-step? For example, an inductor with a parallel resistor?

Thanks, I'm pretty sure I just wired them up direct they sounded nice and went up into the daughters room.  

I was messing around with them the other day and the misses came over and sat down to listen (must be sounding nice) I asked if she could tell which set of speakers she was listening to she couldn't, I said the little one's she said "oh my god no way!"

Honestly proper out of box floaty imaging while sitting about 2 metres away and they were being driving direct from a little Chord Mojo headphone dac/amp with a trs to rca adapter in the picture. For desk top near field listening its a very nice listen. 

 

[Knipester]

It’s like a speaker showroom

 

[Tony_J]

What are those beasts at the back?

 

[rabski]

What are those beasts at the back?

Furniture. Some of us still have some

 

[Tony_J]

Furniture. Some of us still have some

Nah - I meant the tall black obelisks with the 3 BFO drivers... :rockin:

 

[JamieMcC]

2 x 12" Bastanis Mandala crystal free rangers driver with 15" woofer + tweeter assist in a diy (temporary) baffle