Tannoy Enclosure

Dedicated to those large boxes at one end of the room
chris661
Shed dweller
Posts: 2438
Joined: Mon Feb 22, 2010 7:29 am
Location: Sheffield

#61 Re: Tannoy Enclosure

Post by chris661 »

Well, I suppose it depends how far down the rabbit hole you'd like to go.

I don't particularly believe that super-expensive components will make much/any difference. I use caps from this range: http://www.bluearan.co.uk/index.php?man ... Capacitors which suit me just fine - sensible money and won't degrade like electrolytics will.

For inductors, I use air cores where the power levels will be high - the DCR is a little higher, but cored inductors can get non-linear as the core saturates. For medium/low-power use, particularly for large values, I'd go for cored inductors to keep DCR down.

The inductors I use are available here: http://www.bluearan.co.uk/index.php?man ... =Inductors
And have worked exactly as they should every time I've used them.

In your particular situation, if you're doing any simulations in WinISD etc, it's worth including the amp's Zout and the series R of any inductors to check the LF response with the additional resistance in play. I suspect you're right in saying that DCR isn't a huge concern when using an amp with non-zero Zout, but if the inductors add up to a couple of ohms then I'd be taking a really close look at the simulations to make sure that's acceptable.

I'd be interested to see some measured or blind-tested results where crossovers were "upgraded" with components of considerably higher cost but equivalent electrical values to see if there's any difference.

I can say that I have measured large differences between old/new electrolytic capacitors, but that's to be expected - the old caps were >20 years old, and seemed to be acting as semiconductors, introducing considerable harmonic distortion.

Chris
Baggy Trousers
User
Posts: 112
Joined: Mon Jan 01, 2018 11:53 pm

#62 Re: Tannoy Enclosure

Post by Baggy Trousers »

I've only just stumbled across this thread - it's not often that Tannoy is remembered these days.

I haven't read all the contributions to the thread (it's getting late) and can't add much to the discussion from a theoretical standpoint but I am familiar with Tannoys of the original type. I continue to enjoy the incomparable corner Autographs I have owned for more than 50 years. I also have owned a pair of R-GRFs - in fact, I claim authorship of the designation introduced to Hans Hilberink's site years ago - and whilst not being quite as good as the corner variant, like most rear-loaded horns were efficient and worked well. However, my experience with the 15" DC drivers in closed boxes has not been fruitful. Of course, that's what the Lancaster was which, after the Lansdown, was the least successful of any of the standard Tannoy enclosures. In fact, it was dreadful.

Given your preferred dimensions, I think horn loading has to be ruled out; the performance of the Cornetta rather proved that point. In my view, the original Canterbury might be a design worth considering. This was a smaller version of the reflex ported York. Admittedly, it was paired with the 12" speaker but I don't see why you could not fit the larger unit. Perhaps it could be a starting point? Or have I joined the party too late?
Last of the late brakers.
izzy wizzy
Old Hand
Posts: 1263
Joined: Fri Nov 02, 2007 7:02 pm
Location: Folkestone
Contact:

#63 Re: Tannoy Enclosure

Post by izzy wizzy »

The Autographs is what I would build if I was staying in the current house but that's not happening. I have a 3D Sketchup drawing with all the parts laid out accurately but not for now. Would be great to hear some. A friend in NZ has the Pro and what beasts they are but haven't heard my music on them and for some time.

I was going the R-GRF route. Was then going the reflex route and then back to GRFs and now back to reflex/vented. I really like the corner Yorks currently and from what I've simmed, I think I can get what I'm after with something like a cabinet similar to the Amesbury. I think I've only got them to their potential recently and enjoying them immensely of late and there would be more to realise if I wasn't making something a but smaller.

I haven't cut any wood yet so the party hasn't really started. So far, from the modelling I've done and all the reading on the web, this new cabinet will be about 600mm W, 1000mm H, 400mm deep for around 180L volume with three rectangular ports on the front for various tuning options made from 24mm BB ply with the odd brace.

Garage is finally after 10 years a dry place so once that's finished proper and places open up to CNC cut and deliver, I should be able to make a start. Still have to finalise the plans and make the file for the CNC machine.
Baggy Trousers
User
Posts: 112
Joined: Mon Jan 01, 2018 11:53 pm

#64 Re: Tannoy Enclosure

Post by Baggy Trousers »

I have no personal knowledge of the Amesbury, which, I think was a R-York.

The triangular variants of Tannoy cabinets were designed by Ronnie Rackham before the widespread adoption of stereophony and were intended for corner placement. The rectangulars were introduced to meet a marketing requirement demanded by the new-fangled stereo systems and certainly not because of any superiority of reproduction; by and large their performance was inferior. The awful Lancaster (for which there was not a corner variant) was merely a cheap plug and play box to shift more product and I remember these being stocked by Comet which was a sales philosophy very different from that normally adopted by Tannoy. It did the company's reputation no good at all. Partly due to the Japanese influence, strong at the time, and against Rackham's advice (which Guy Fountain often ignored), excessively large cabinets were offered, but without exception, the Autograph Pro, the R-GRF Pro and the ridiculously large (as big as a Jensen Imperial), the Tannoy Imperial were failures. I include the Harmon-inspired HPD in this list of contemporaneous efforts to be "cool", but I suspect few would agree. You are fortunate to have a proper West Norwood model.

It could be argued - and often has been! - that the big dual-concentrics represent an obsolete approach favoured at a time when houses had bigger rooms and were more solidly built; they no longer are relevant to today's tastes and domestic conditions. This is an argument in which I do not have to engage; to me my set-up of Autographs fed by a Mullard 5/20 is all I need or want. Nevertheless, replicating/improving in the way people commonly did continues to be fun. I have built several clones, including the R-GRF and the Canterbury, the latter being a delightful speaker, but unless you intend to paint the finished product, I would not use BB plywood. Invariably, I have employed marine quality birch ply which is absent of voids and readily accepts a veneer. The R-GRF is easy to build, being a series of rectangular sections making up the 9,5 foot folded horn. The Autograph, on the other hand, is a complicated swine but well worth the effort. At least for me - a Magnaplanar devotee probably would disagree. I have the original factory drawings of both, if they are of interest to you.
Last of the late brakers.
izzy wizzy
Old Hand
Posts: 1263
Joined: Fri Nov 02, 2007 7:02 pm
Location: Folkestone
Contact:

#65 Re: Tannoy Enclosure

Post by izzy wizzy »

The Amesbury was for the HPD https://www.hifiengine.com/manual_libra ... bury.shtml. My corner Yorks were made by me as a trial, not too far from West Norwood and here we are nearly 16 years later. They weren't really finished https://izzy-wizzy.com/?page_id=60. The page hasn't been updated to show where they are now but they look the same but with further crossover mods.

I was aiming to use voidless BB ply. It comes in many grades and will be veneering them. I like the corner shapes but can't accomodate them in the future hence the rectangular shape. Many of the later Tannoy cabinets didn't do them justice but that can be fixed these days. I've modelled the old cabinets and have been aiming for a similar result from the new design with flexible tuning. These ones will have to be finished as they'll be in a shared living space for a bit. After that, who knows ... maybe an Autograph :)
izzy wizzy
Old Hand
Posts: 1263
Joined: Fri Nov 02, 2007 7:02 pm
Location: Folkestone
Contact:

#66 Re: Tannoy Enclosure

Post by izzy wizzy »

Got the wood cut out for the cabinets. 24mm BB ply. They will be aboout 220l volume with a port.

The port is planned to be adjustable so a rectangular hole on the front with a removable rear I can adjust for size; length and area.

I'm considering making the hole big enough to entertain aperiodic at some point but that makes the hole a lot bigger than that for a reflex cabinet so still wondering about that bit.

Joints on the corners will be rebated. The front panel will be rebated into the sides and top/bottom at about 6mm depth. Rear will be screwed on into a rebate.

Question I have is what's a good, easy available glue that has decent open time for me to jiggle it all together?

I wanted a teak type finish but teak is out of the question. Iroko was next choice but that's very hard to source. So maybe walnut, not the super dark walnut. I've only veneered small cabinets in maple with glue sheet ironed on before. Any hints on sources for veneer welcome.
chris661
Shed dweller
Posts: 2438
Joined: Mon Feb 22, 2010 7:29 am
Location: Sheffield

#67 Re: Tannoy Enclosure

Post by chris661 »

I usually use a decent-brand (Evo-stick? Can't remember) PVA glue, and a load of clamps. You get a few minutes of wiggle time.
You could also use a poly-urethane based glue. Would also work fine, but I prefer PVA because you can peel it off your fingers.

Chris
vinylnvalves
Old Hand
Posts: 476
Joined: Sat Jan 26, 2013 12:08 pm

#68 Re: Tannoy Enclosure

Post by vinylnvalves »

I have used this before..https://www.axminstertools.com/titebond ... r-ax836045. Thermally activated glue, like hide glue works well with veneers if they aren’t too thick. Iroko and walnut are easy to glue as not oily. Smiths epoxy is that I have used with teak successful- West Bro’s have an epoxy for teak too. Epoxy works well as a CLD too. A vacuum bag with a modified track pump to remove the air works well to clamp evenly over the surface.
izzy wizzy
Old Hand
Posts: 1263
Joined: Fri Nov 02, 2007 7:02 pm
Location: Folkestone
Contact:

#69 Re: Tannoy Enclosure

Post by izzy wizzy »

Went for Titebond 3 in the end when I started to look at open times of the various PVAs. I think I needed something quite a bit longer than the usual 5 to 10mins and got it from Aminster.

The whole veneer thing is a bit scary but maybe I just ned to read a bit more/watch more Youtube how to videos. Will look into the vacuum bag thing.
steve s
Shed dweller
Posts: 2305
Joined: Wed May 30, 2007 6:19 pm
Location: east yorks

#70 Re: Tannoy Enclosure

Post by steve s »

Colin is the veneer expert he does a brilliant job.
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
izzy wizzy
Old Hand
Posts: 1263
Joined: Fri Nov 02, 2007 7:02 pm
Location: Folkestone
Contact:

#71 Re: Tannoy Enclosure

Post by izzy wizzy »

Been making a lot of sawdust and ready to glue up which is a bit scary. Hoping I can do it with cargo straps and corner blocks as I have no clamps. I've tried to challenge myself by not using battens and using various housed joints. I like the Altec model 17 shadow line around the baffle so have done similar. Port will be mounted from the inside and be configurable for length and area but not 100% sure how that will work yet.

Have watched a load of YouTube and think the way forward for veneering will be using something like Titebond 2 iron on method. I can't use cold press as have no method of applying even pressure and contact adhesive is scary at these sizes. The iron on method I've tried before with glue film and the Titebond method seems achievable fingers crossed.

IMG_20210503_183512652_compress82.jpg
IMG_20210503_183512652_compress82.jpg (166.83 KiB) Viewed 146 times
izzy wizzy
Old Hand
Posts: 1263
Joined: Fri Nov 02, 2007 7:02 pm
Location: Folkestone
Contact:

#72 Re: Tannoy Enclosure

Post by izzy wizzy »

First attempt at gluing up failed so had to pull apart and clean off. Wasn't prepared for inability to slide parts together like when they're dry especially the rebated front panel in the sides.

Thinking I'll have to find a way to glue up in stages while maintaining alignment and accuracy. Might have to invest in clamps as I can't get the strapping in place fast enough.

A bit more thinking to do. It was always going to be a challenge.
User avatar
IslandPink
Social Sevices have been notified
Posts: 8521
Joined: Tue May 29, 2007 7:01 pm
Location: Denbigh, N.Wales

#73 Re: Tannoy Enclosure

Post by IslandPink »

You should put a human being next to those, then people would appreciate how big these 'stards really are !
"Peridots and periwinkle, blue medallions Gilded galleons spilled across the ocean floor" ( Mitchell )
User avatar
Dave the bass
Amstrad Tower of Power
Posts: 11620
Joined: Tue May 22, 2007 4:36 pm
Location: NW Kent, Darn Sarf innit.

#74 Re: Tannoy Enclosure

Post by Dave the bass »

Look at the amount of sawdust on the floor!

Top work Izzy! :)
"The fat bourgeois and his doppelganger"
Post Reply