Doesn't quite have the same ring as "Cantebury", "York", or "Lancaster"!Quote:
Originally Posted by julesd68
What seems to suit it better is "Bismark"!
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Doesn't quite have the same ring as "Cantebury", "York", or "Lancaster"!Quote:
Originally Posted by julesd68
What seems to suit it better is "Bismark"!
Looking good, Paul!
Great idea - if you want, we could run with that :)Quote:
I'm going to add a small brass plate with the name of the loudspeaker at the back. trouble is, I haven't thought of a name yet....could this be an AoS competition I feel coming on?
Marco.
Quote:
Originally Posted by Reffc
Tannoy - Dagenham and Redbridge?
On a more serious note will these be available commercially Paul?
You could have a whole range named after WWII German warships - Graf Spee, Tirpitz, Prinz Eugen. Except none of them came to very good endings.Quote:
Originally Posted by Reffc
Seriously though I am really enjoying following this build. I guess I am not the only one whose lack of a workshop and the necessary skills preclude me from doing something similar. Particularly like the measurements being used to match the speakers to the room they will live in. That really is the optimum way to do it IMO.
So - a seriously poorly back and recent surgery ... and your building a pair of 75Kg speakers which will inevitably need a lot of moving around ... :doh: :lol:
A name? Hmmm .... how about "The Dursley Dreadnought" or "Spinal Suicide" :)
Thanks for all the feedback folks. To answer a few questions:
If they work really well, then it would be a good thing to offer others the chance to own a similar pair, but they'll have to perform well. I wont offer them if performance is anything short of excellent.Quote:
On a more serious note will these be available commercially Paul?
Thanks Marco, appreciated. I like the idea that after so much work, they deserve to be named! I'm currently looking into musical associations which haven't all been done before (like "Concerto" for example). If they work in harmony with the room, then "Reference Harmony" would be apt if a little twee!Quote:
Looking good, Paul!
Quote:
I'm going to add a small brass plate with the name of the loudspeaker at the back. trouble is, I haven't thought of a name yet....could this be an AoS competition I feel coming on?
Great idea - if you want, we could run with that
Marco.
Yesterday 21:33
Having a few tuning issues at the minute and now tempted to reduce the ports to a single port but have a few available for in room running at EBS 28Hz (F6 response) and 32 Hz F3 tuning. Seems the sensible way forward rather than use the twin ports which model quite peaky at the Alex Garner suggested tuning.
Some more progress. Back panels completed and glued in, panel painted in black and two coats 90 sheen lacquer applied. Cut out at base is where the removable panel for the crossover and binding posts goes.
http://i1140.photobucket.com/albums/...psad5cbeb8.jpg
Same detail, other cabinet:
http://i1140.photobucket.com/albums/...ps914c12bb.jpg
Spent part of this afternoon lengthening the ports for EBS tuning by using some PVC pipe couplers glued to the ends then used a heat gun and a plastic handle from a hand tool to form flares on the entry into the ports. Once completed, the rest of the afternoon was spent priming the inside of each cabinet for the bitumen sheeting. A particularly smelly and messy job! Insides now sealed:
http://i1140.photobucket.com/albums/...ps94c46a2a.jpg
A picture of yours truly standing next to one of the cabs to give a little scale!
http://i1140.photobucket.com/albums/...ps8b54d23e.jpg
Tomorrow will be spent fitting out the internals. The front baffles are now laminated and veneered. If I get time, they'll be cut for the drivers and ports tomorrow. Looking good for completion of the cabinets next week.
They're beginning to look very posh Paul!
Some more progress. Spend the entire day getting the internal damping in place. Fitting the bitumen sheeting was a filthy job. Went belts and braces and used 10mm industrial staples in case it ever thought about peeling itself off again!
Used 12mm dense wool felt around driver chamber, top and bottom panel (on top of the bitumen), then 40mm acoustic foam and finally, a 35mm layer of Monacor lambswool/BAFF around just the central area where the driver will be. This wont impede airflow to the vents which will be located below:
Fitting out the central chamber:
http://i1140.photobucket.com/albums/...ps60fa237d.jpg
Damping sheeting all in and wool felt glued into place:
http://i1140.photobucket.com/albums/...ps5413b2ce.jpg
Close up of damping layers:
http://i1140.photobucket.com/albums/...ps0b3da28a.jpg
Central chamber fitted out with lambswool/BAFF:
http://i1140.photobucket.com/albums/...ps5c8c049e.jpg
Front baffles now veneered but unfortunately the magnets (6nr) can be quite clearly seen beneath the veneer which is a shame. As these have been bookmatched and I dont have enough veneer to re-do them, I'll just leave as-is. Holes for driver (rebated hole) and ports have yet to be cut. The underside of this 24mm slab of ply has been laminated with 6mm MDF with cut outs for the braces:
http://i1140.photobucket.com/albums/...pse3b9663d.jpg
Should have the speakers completed by Wednesday.
Excellent workmanship!
Cab profile look very similar to some of the later Kef designs.:)
A...
Beautiful!
Can you imagine how many thousands this would cost if done as a commercial venture for production speakers? Mass production or not, these boxes wouldn't be cheap!
Thanks for the thumbs up guys...it's been a learning journey and a lot of hard work! The proof of the pudding and all that though, so waiting with baited breath to hear what the outcome will be next week. It's been quite an expensive project too, probably could have bought a really good pair of speakers for what this little lot has cost, but to buy somthing LIKE this would probably set me back 5 times what it's cost me.
A little more progress this evening. The removable panels for the crossovers are completed although I may try and finish them off with a better quality lacquer coat. I've now fitted the crossovers and binding posts into place and have just finished soldering the crossover connection to the binding posts which are silver plated copper:
http://i1140.photobucket.com/albums/...psee3c9cc6.jpg
The binding post side (rear of cabinet) can be seen next to the inside containing the crossover. I've rebated the panels and added some compressible draught excluder strips to act as gaskets:
http://i1140.photobucket.com/albums/...psc877351b.jpg
Paul, have you upgraded the wire from the the speaker connector to the tweeter on the Tannoy's?
If not I'd seriously suggest that the crossovers should be hard wired to the speaker terminals. :)
Looking amazing matey, really good. They look like Wilson Benesch.. but obviously more beefy than their Pringle tubes they call cabs... LOL
I haven't Joe as I'm unsure what an upgraded wire looks like ;) They're fine mate, the connectors are new old stock and fit really firmly. Yes, it would be better to hard-wire but the drivers may be in and out of the cabs for a while so the plugs are a better idea for now.Quote:
Originally Posted by The Black Adder
The one thing that does concern me is the proximity of the inductors on the PCB. I must speak with the builder of the crossover as these inductors should be much wider spaced than they are.
Great work Paul, impressive speed of progress too.
Hope I'm not taken this too ot; when wiring internals, would it ever be wise to use the same wire as the speaker cable you've used?
The logic behind the question is that all speaker cable has a sound, if you like it then it would be best to preserve it, right?
Hi Martin, thanks.Quote:
Originally Posted by realysm42
RE the cable query, I don't believe in cables (ie cable core conductors themselves) having a a sound, just in having LCR parameters, so providing the cable is fit for purpose, I'm happy. Whilst I do think that interconnect signal cables (by geometry, materials and design) can differ, wiring for a x-over from the binding posts is a very short run and any impedance differences between that length (about 150mm) and the main speaker cables is insignificant. Also, the speaker cable impedance is only a small fraction (less than 5% of the circuit impedance of the speaker). The connections are all hard wired bar the 4 pin connector to the speaker and this is a NOS item which has been cleaned and treated and is a firm fit. The wired to the tweeter and bass drive units are all brand new. :eyebrows:
Quote:
Originally Posted by The Black Adder
+1 Wot Joe sez. The original wire is pretty crap and the connector (however snug) isn't the best, direct wiring is the way to go.Maybe something to do when everything else is all sorted.
Crossed wires methinks! ALL wiring is new and NON Tannoy. The only thing that is Tannoy is the NOS 4 pin plug and there's nothing wrong with the connection which unlike my old ones, isn't corroded or anything like that. The original crossovers used crappy lighting flex (which when pulled apart was badly corroded). I renewed the wiring on my original crossovers which I have kept as spares. Changing the wire I have will make zero difference. Soldering in place of the 4-pin may be something I do in the future but only once the crossover tweaks have been done, so its a long way off just yet.
The proximity of the coils could be better to be honest.
They are ok but I too would question the design. For me it would have to be right and it would bug me if not. But that's me,,, lol
No worries, if your swapping in and out then it's best to stay with the connector. But as Tom said, no matter how good that connector is the contact is still a weak point regardless of how good the plug is.
What I've learned is that any sort of plug on the outward from the crossover can make a difference to the sound.
Hi Joe
yes, you're right of course but it's by degrees and some things have a more significant impact than others.
I've spoken with Mark Pitcher today regarding the inductor coil spacing and I think Mark will be amending future designs as a result.
I'll be lifting the inductor from where it is and moving it to the far side of the PCB and soldering new connecting wires to the existing wiring point on the PCB. A bit of a pain, but better to get things right.
I may also be swapping out the notch filter 30R resistor for a 35R value instead just to tame the HF response down a little (not much) either that or replacing the 4mH inductor (smaller of the two which are next to each other) for a 4.5mH one as that should have a similar effect.
One thing at a time though!
Got to find time to finish the speaker cabinets off next week. Will report back once I've done that!
Just back from the workshop. Both cabs received their 2nd coat of lacquer. The polystyrene in the pictures is just there to plug the holes during lacquering and aren't some new fangled driver design! Some pictures as promised:
http://i1140.photobucket.com/albums/...psff36ebe2.jpg
Have yet to fix the edge strips which are made from Walnut. They're all ready and have had radii machine on the baffle edge. Also out of sight are the custom made baffle frames machined from a solid lump of ply (magnets now glued into place and the magnetic covers work really well. 6nr 10mm diameter by 3mm deep magnets in both the speakers and the covers are about perfect).
Some more pics:
Close up of side panel after 2nd coat of lacquer:
http://i1140.photobucket.com/albums/...ps53c1490d.jpg
Rear view:
http://i1140.photobucket.com/albums/...psdb3f3de9.jpg
Side view:
http://i1140.photobucket.com/albums/...psdc5eb2ff.jpg
View from a step ladder!
http://i1140.photobucket.com/albums/...psc99c61b3.jpg
50mm deep plinth which protects cabinet. Its curved to the same profile but stepped in:
http://i1140.photobucket.com/albums/...ps7dd5cb6c.jpg
The cabinets just need a final slight sanding, 2 more coats of lacquer, the edge strips gluing into place, the grills finishing and the drivers and crossovers fitted in.
I reckon another 3 to 4 days. Awaiting more lacquer which won't be here until next week.
Fantasic Paul.
Though I'd be busting to have a listen long before the lacquering was finished .....
I have some stand-ins to keep me going Tom, a pair of Mission 760i's sat on some plastic stools :eek:Quote:
Originally Posted by montesquieu
Sounds ok, but where's my bass gone :scratch:
Yes, the sooner the big cabs are insitu the better.
Still need to think of a name for them as if they perform as planned, they'll be welcomed into the RFC fold :cool:
Reference Harmony perhaps?
Reference journey; its what you've been on to get here and I'm not just talking about the speaker design itself, sounds like you've been on this path for an few months at least...
Spot the difference:
Before:
http://i1140.photobucket.com/albums/...psee3c9cc6.jpg
After:
http://i1140.photobucket.com/albums/...ps840fb1f4.jpg
Almost there. Rounded Walnut oiled edge strips now on. 3rd coat of lacquer applied today and ports sprayed black and ready to go in. Just got the grills to finish today and the speakers are finished.
I do of course have the crossovers to rebuild but will use the one's I've got unit I can get time to build the Foo components ones. Hope you like the (almost) finished speaker. I think that the Walnut against the Ripple Sycamore works better than expected and really finishes them off well:
http://i1140.photobucket.com/albums/...ps9dc0b698.jpg
Its a brace of cabs!
http://i1140.photobucket.com/albums/...psd02a0c58.jpg
Lacquer really brings out the depth of the grain although hard to see on the photo:
http://i1140.photobucket.com/albums/...psc1662635.jpg
http://i1140.photobucket.com/albums/...psfff6197f.jpg
Imposing view of 65Kg of 1.28m tall cabinet!
http://i1140.photobucket.com/albums/...ps47e44435.jpg
:stalks:, put the drivers in and connect up!:):popcorn:
When are the doors and the clothes rails being fitted?...:lol:
Seriously, looking magnificent... Yep, that is a better orientation for the inductor on the crossover. Just make sure it's glued down really well. I'm sure you will.
Cheers Joe
Grills finished this afternoon and I've since spent 4 hours hunting down all the parts needed for the up-market crossovers. Had a heck of a job getting hold of good quality inductors that would fit on the PCB but finally traced some Jantzen air cored ones plus one P-core for the HF. Total bill for all the crossover components was £165 for the two, so well chuffed seeing as there's some very tasty components (including 3% Clarity ESA Caps).
I'll install the Ebay crossovers for the time being until all my parts arrive and I can build the proper ones. I found a few issues with the Ebay ones and having spoken with Mark (he's a really nice guy) who built them, it's apparent that all's not quite as it should be with them, so he's sold me a few un-populated PCBs with which to build my own. The HF inductor is the wrong value, the 47R resistor doesn't account for the original autoformer inductance ratio (green tag connected in circuit to the Orange = 1.4 times) so that resistor should be 35R, and the HF bypass cap is too high a value (should be 1.5uF). I should have done more homework before buying the one's I did but Mark built them in good faith so I haven't chased for a refund. You win some, you lose some.
Speakers being installed tomorrow so should have first impressions for you within a few days, albeit with the "wrong" crossovers fitted.
Yep the bypass cap should be 1.5uf. I used the Russian cold war versions, it's a PLIO cap and are amazing.. better to my ears in that position than an MR.
The 47R resistor is correct or as close as can be to 50R. But with an autoformer you can take that resistor out of circuit as the autoformer on one of the settings (can't remember which) is near enough the correct impedance.
I don't think that's actually accurate Joe. The autoformer has an impedance ratio across the coils between green/orange so the driver doesn't actually see 50 Ohms at all settings, only for the one where the ratio is 1:1. I'll double check that though as you've got me thinking. It's the "green" autoformer tapping that I'm emulating for the fixed inductor/ resistor values.Quote:
Originally Posted by The Black Adder
Hmm.. ok. I'll take a look in to that, Paul. But I do know that some autoformer values were published wrong. It took someone to unwind an original autoformer to find it's correct values. The original circuit diagram knocking around on the net is wrong in places but the 50R value is consistent on both the diagram and the original crossovers.
Lovely build Paul, they look really beautiful and really informative regarding cross overs...nice to know someone in the country is experiencing similar headaches as me at at the moment:) They will surely be a credit to your clear expertise and knowledge.
This stage is frustrating, you just want to listen but the final details (as we agree) make all the difference, looking forward to more.
VB Si.
That's true Joe but the 50 Ohm is only 50 Ohm at one of the settings. At all other settings the value is modified by the autoformer's impedance/inductance ratio and at the highest autoformer setting, it's out of circuit as the autoformer presents sufficient electrical damping to prevent HF ringing without additional resistance.Quote:
Originally Posted by The Black Adder
My comments are aimed at a fixed inductor value replacing the autoformer so the resistor value depends upon the tap you want to emulate as all taps have different inductance and all but one have a voltage lift too.
The only tap which is electrically flat is the green tap and that equates to 2.8 to 2.9 MH at 0.7 Ohms inductor resistance (as measured...I don't pay any attention to what might be stated on various internet resources as I'm basing all values on those as measured with my own original Tannoy crossovers) I'll check it out and make sure that the correct value is stated here to avoid confusion!
lol... Crossed wires quite literally, that's what I meant. heheh :)Quote:
Originally Posted by Reffc
Cheers Si and I better appreciate now what you went through although yours probably took way more time than mine. I'm up to 230 hours now (design and construction) although the initial design was a major headache as it was from scratch. At least I have the plans now!Quote:
Originally Posted by simonms
First listen will be tomorrow albeit using crossovers which I believe to have a few flaws on them, so I am expecting things to sound a little bright but with better bass response than before...we'll see! The little details are what matter and ultimately what trip you up. I've spent 80% of my design time on 20% of the design if that makes sense.
LoL :lol:Quote:
Originally Posted by The Black Adder
I went through 3 crossover designs/variants/components/connections, you name it. Also 6 months of listening... It's hard work but great when it's right.
I'm happy to share the wealth if needs be... :)
Hi Joe
Right, finally got to the bottom of it and I was correct first time round. It SHOULD be 34 (or 36!) Ohms on fixed inductor settings. The reason:
Look at the circuit diagram. the green tapping may be electrically flat (ie no step up) BUT the 50 Ohm resistor is not connected to the green tap, but to a higher one where the impedance ratio between taps is 1.4. That is the same as a reflected impedance ratio across a transformer, so you have to divide the 50 Ohm resistor value by 1.4 which gets you to 35.7 ohms (soz, not 34, but 36 Ohms...good job I checked :lol:)
As far as the rest of the circuit is concerned, if a fixed inductor value of 2.9mH is chosen without the autoformer, then the only correct resistor value that can be substituted is 35.7 Ohms but a value of between 34 and 36 Ohms should be fine. I'm using two 68 Ohm resistors in parallel as that's what was available to me.
It's a difficult one to spot and it takes patience when reading the original circuit diagram with the autoformer, which is why most people I think get it wrong.
Ah.. yes, sorry. I forgot your using a 'fixed' inductor for some reason. I'm using autoformers... Sorry fella. That is correct with a fixed inductor.
Yes I remember the diagram now, in fact I had mine incorrectly connected at first before I looked at the diagram again. Well, noticing something wasn't gelling made me look at the diagram again.. lol, live n learn.
My bad...I based the 34 Ohm value on an impedance ratio of 1.42Quote:
Originally Posted by The Black Adder
That, of course, is the voltage step up ratio between green and orange taps :doh:
The reflected impedance ratio for all intents is the same as the inductance ratio which is 2.0
Therefore the correct resistor value for a fixed inductor of 2.9mH is 25 Ohms.
Hmm.. I seriously doubt the discrepancy would be that audible though, not on that resistor.Quote:
Originally Posted by Reffc
I was fortunate enough to be able to spend a wee bit of time recently in front of a pair of Glenair 15's. there is something quite beguiling about them. Effortless. The music just seems to flow. I didn't get a sense of the music being radiated out from them. Sort of like I was in amongst the music somehow. This was via some Line Magnetic Valves. I would love to hear them on the end of the big Modwright integrated. If I had $12-$13,000.00 NZD to spend on a pair of speakers these would be at or near the top of my audition list for sure.:)Quote:
Originally Posted by Reffc
Right then folks (queue drum roll)............................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. ....................want to see some pictures (no, not those sort of pictures...some people just have a smutty mind!)............................................ .................................................. .................................................. .................................................. .................................................. .......Here we are. All finished:
Grills on:
http://i1140.photobucket.com/albums/...pse56576a1.jpg
http://i1140.photobucket.com/albums/...psd90800aa.jpg
Grills removed. Notice no nasty plastic speaker grill sockets...these are magnetic :eyebrows:
http://i1140.photobucket.com/albums/...psd9cf680e.jpg
http://i1140.photobucket.com/albums/...ps0ed3ba1c.jpg
http://i1140.photobucket.com/albums/...ps71ca276f.jpg
http://i1140.photobucket.com/albums/...psb3ca281b.jpg
Final all up weigth was heavier than expected at 75kg :eek:
Initial impressions:
Very deep but well controlled bass. Playing Dark Side of the Moon, the initial pulse at the start was deep and powerful enough to make you feel the note in your insides!
Treble energy a little high due to the crossover issues but that will be resolved.
Mid range is a wee bit recessed :scratch:
I'm thinking that I need to remove some of the wadding (I can always put it back if needs be), so the long haul now starts with tuning them. It was too much to expect a new design to be spot on first time but it's mighty close!
:wow:
One word describes what you've done Paul, AWESOME.
Geoff. :)
Not my cuppa Tea Paul but you have clearly made a loverly job of them..
:thumbsup:
They look superb... Well done you. A few tweeks I guess is always the case. It pays to be methodical with them too...
:drool:
Smashin' job :clap:
Thanks fellas. Yes Joe, little detailed issues matter (at least to me they do) so it'll probably take quite a while getting them to sound exactly as intended. they;re really not that far off now. Bass is incredible...really deep, detailed and not at all boomy nor afflicted by overhang so I guess I got something right with the cab design!
A few more shots...finishing touches (NOS Tannoy Badges):
http://i1140.photobucket.com/albums/...ps21b07d9d.jpg
http://i1140.photobucket.com/albums/...ps8daf982c.jpg
http://i1140.photobucket.com/albums/...psc60f88c8.jpg
http://i1140.photobucket.com/albums/...psdccbfc8a.jpg
http://i1140.photobucket.com/albums/...psef7f716d.jpg
Rear view of curvy derrière:
http://i1140.photobucket.com/albums/...ps86516576.jpg
Binding posts on removable rear panel which also houses the x-overs on the inside face:
http://i1140.photobucket.com/albums/...psbb8bb122.jpg