DIY Tannoy GRF's - Long with lots of pics

[Speedysteve7]

I recently built some Tannoy rect GRF replica's out of 21 / 24mm birch ply.
I am happy with the result and thought to share it with you guys.

I be used my Tannoy Berkeley HPD 3828 15" drivers.

They are a copy of plans found on T'internet but to the same dims as a friends with golds and made of 18mm ply throughout (which I've heard).

Here is the cutting sheet plan.




Idea was to make the round front panel cut compatible for both 3828's and Golds / Reds.

A friend kindly put the data into a horn calc prog and things came out very much the same as for his 15" Monitor Golds (see below).

HPD params



HPD response


Monitor Golds params


Monitor Golds response


Apparently the comb filtering is normal. So it was agreen light on HPD's working on paper.

Next the ply arrived on palette - very well packed.
Unpacking revealed all parts accounted for.
All the machine faces are tip top perfect.
I put all parts for one speaker on the scales - yikes ~55kgs. Gonna be heavy things with plinths and drivers etc. I think castors may be a good idea
I will need my trolley and a ramp to get them out of the garage from then on it's all flat to the lounge - best done when wife is not around. Honey I grew the speakers.

Pics

Palette - with protective sheet of waste ply removed.

[Speedysteve7]

More pics
2 Speakers worth - doesn't look like 110kgs there but there is!






So the build started

Lining it up






Driver mounting plate






Front panel in

[Speedysteve7]

next 10 pics

Castors from wardrode base that had been in the loft for 11 years


A few more evenings and the first one was almost ready

Here's how it would have looked using the Berkeley grilles



Boy the castors were a good idea!



The one on the right is rubbed down and two thin coats of polyurethane


They are now named Bertha & Big Bob by the family?!


The felt took a few says to arrive so I had time to cut the slots for the crossover panels and put the terminal posts on the backs.

Just 3 internal horn baffle and 2 reflector pieces in each speaker to go and transplanting the drivers etc over.

Pic of felting I used and blind nut fitting (re-used from Berkeleys).





First one in place



Wife likes the colour at least...

2nd one ready



All together



More to follow

[Speedysteve7]

So how do they play.
I chose Ry Cooder Paradise and Lunch to start with - fantastic slide guitar esp Fool for a cigarette.
On to Jan Johansson (Swedish Jazz pianist - died 1968 car crash :-(.
Wonderful european / different take on jazz.

Well, what can I say about these speakers then.
Firstly they were a bit of a shock. Different tonal balance and very open.
Loads of deeeeeeep bass. Not boomy or out of control just deeper than

the Berkeleys could muster.
Mid and treble they are quite laid back. Went to level one on the treble
on crossover - all speakers should have this facility

There is plently of detail and depth. Effortless and instruments sound
more like instruments. That timbre / resonating clarity you should get
with music.

The Berkeleys are good - these cabs just take what the drivers are
capable of to another level.

The more I listen the more I like them and the improvement is apparent.

These 3828 HPD drivers are very good - clearer in the mid and treble
than I heard Golds that are a bit warmer and cuddly.

Taking almost as long as one speaker it was speakers covers time.
Wife chose the cloth colour. She does not like the drivers showing
really

First the frame surrounds (wood came from Wickes clearance bin at 0.99p)



Next some stretching & stapling



One done



Then to mount them. I ordered Wilmslow speaker grill lugs

And the result





Next some GRF badges to finish them off...
Listening to them some more and more stuff- amazingly good speakers.
These are keepers!

Chosen badges arrived and duly fitted. Looks almost complete now.



Finally I made some castor hiding plinths and varnished them. On carpet
(my intended flooring for the music room - another project) they just
brush surface allowing the castors to do the wheeling for convenience
but not leaving a noticeable gap.





Well that was a great fun project - I am happy to discuss making a pair
for anyone interested.
Could also be conventional curved top and base style too - I like the
more modern mitre finish in our room though.

[Zen Mod]

[DaveCan]

Wow really nice build and retro/ new look, great job!!

[c2cthomas]

[oublie]

Nice walk through,

who cut your plywood for you or is this a kit?

[Speedysteve7]

Originally Posted by oublie

Nice walk through,

who cut your plywood for you or is this a kit?

A company called Avon Ply. They did a really nice job on the mitres and everything was done to 0.1mm accuracy.
As you could see packing was very good - no risk to those fragile mitred edges.

I am currently acquiring wood to build two more sets for fellow 15" Tannoy owners. Both HPD's of the Alnico variety.
They came round to my place a couple of weekends ago and threw all the hard to play stuff (that their Berkeley's and similar cabs to Chatsworths struggled with) at the GRF's and after a while said - "I've got to have a pair of these"

There is so much more information coming out at sub 200hz level it's amazing but they are nicely balanced too.

[AKN]

Hi,

Very nice!

I'm a Tannoy owner myself (3808) so I can sort of imagine how well these sound.