Looking for European vintage speaker advice

The problem with these tweeters (they where lower middle class at their time) over time the ferro fluid is getting thicker and drys out.

Apart from that (they may not have FF), the capacitor did sound bad even when brand new.
While you may not hear the difference between a WIMA 1.95$ 4.7uF industry film cap and a 98$ Munktorf "platinum in fish oil" cap, changing Benic for the 1.95$ part is in most cases clearly audible.

The whole x-over is a bare minimum and the cheapest it can get. If I see it right, it is 12dB/Oct for the tweeter and no limit for the woofer.
There are many woofers made from paper, that just tapered down without any resonances and can be used without x-over. This one got a foam surround and a bored out pole piece, so even with a steel basket, this is a well constructed, modern driver.

When these speakers where new, plugging a 200$ pair of speakers into a 2000$ amp could give very surprising results, compared with expensive speakers.
Mission sure made something right, using cheap, but well build parts, while many "high end" manufacturers produced horrible speakers, containing expensive components.
For example TSP parameters, the following construction rules and simulations where considered nonsense and not matching the reality by many involved in speaker building. A lot of sales talk and unfounded voodoo nourished by not knowing how to do it right.
Like today, where a well made x-over from good industry parts beats any carelessly constructed x-over from expensive boutique parts.

So please put these antique test reports in the right context.
These where speakers that did nothing wrong, while this was not the norm at that time.
Sure they can not match a well made speaker of today, but they do not sound “ugly” as many expensive, ear punishing products of that time and are still well suited for back ground music in a kitchen or workshop.

If you really want to step up in sound reproduction and keep the cabinets, buy a good, proven and well reputed loudspeaker kit, 300-400$ a pair, matching the cabinet. Follow the instructions and don't get creative!

Leave one speaker as is and then compare to the converted one. You will be very surprised, even as the real surprise will come with both in stereo.
 
OK My bad but even so it is crossing way too low for that tweeter.
Possibly a Peerless mid-bass?
A better tweeter by far in those days would have been the D27-05-06 which is now available as a Peerless branded unit.
https://www.parts-express.com/Peerless-D27TG-35-06-1-Silk-Dome-Tweeter-264-1022
Cheap for what you get and I'd use it with that XO if the cap was changed; just as an experiment. Might need a small resistor in front of the XO tho. would need about 2dB of padding
 
If you have years of experience, solid electronic background and know how to handle your measuring microphone, no problem.

If you just opened up a speaker for the first time in your life and do not know what a bipolar capacitor is, sorry, no.

Changing the tweeter would be constructing a new loudspeaker.
Why are good loudspeakers so expensive? Because it consumes a lot of time, material, measuring equipment and samples to try out.
 
Focal does not sell any speaker for DIYS. Please understand that.
Please do not come up with the bad idea to put a car HIFI kit in your cabinet, as some are still floating around. Such speakers are spezialised for car interiors.

Also, sorry to tell you, the last DIYS speaker sold by Focal were not that fantastic any more, compared to the competition. They did not match Scan Speak, Seas or Viva, Peerless etc. and where wildly overpriced.
They pulled out of the business, officially, because DIYS people would buy some tweeter and woofer, wire in some universal x-over, found somewhere and blame Focal for the resulting, low quality sound. Damaging the reputation of the brand. The truth may be nearer to the fact that they didn't like objective measurements and comparisons, which are common in the DIYS scene. That and they could not make enough money from their chassis any more.

If you want best price/performance ratio, go Dayton. If you want better than their premium line, be prepared to pay a some more.

Remember, you do not search for a Tweeter and woofer, but a complete kit, including an x-over, made for a compareable cabinet.
Maybe you do not think the x-over is all that important, as your speaker only used two components. Nothing is less true.

Next, there is no brand sound in DIYS HIFI kit's, like in commercial speakers.

The usual aim is to design linear speakers, that do not boom, buzz or hiss.
Read the description of a construction, usually the text will be quite objective, not sales talk as you are used to from the industry.
Next, you will find opinions to any kit on the market. Read them with a grain of salt, as people tend to be over optimistic when the build something by them selves. Also some may have done anything wrong and ignored the instructions, these guy's then post rude comments, even if the kit is a gem.

If you want beef, tell us what you want to spent. $.
What tools do you have and know how to use? Jig saw? Drill? Router? Complete wood work shop or kitchen table?

Do some more pictures. Can the chassis be mounted from the outside? From the inside is less universal.
 
If you want a simple but very effective and high quality kit, look at the Seas A26kit. It's relative simple to build and a proven design based on the legendaric Dynaco A25 that used Seas drivers. The original A25 had the Seas H087 tweeter, one of the best dome tweeters ever made. They now use their equivalent of it, the TC0035C-02. The woofer was the Seas A25TV woofers, of wich the modern Seas A26RE4 is the modern equivalent. The crossover is very simple, but very effective.

The kit is not sold as a kit, but all parts are easely found and all documentation is availeble on the site: http://www.seas.no/index.php?option=com_content&view=article&id=475:seas-a26-kit&catid=66&Itemid=250
 
If you go to Seas, which is one of my favorite brands, the Mimir would perfektly fit your cabinet.
It is a true high end product that will challenge any speaker it's size you can find in your local HIFI stores and sure win the contest.

I give you a very serious warning, if you go for such high class speakers, 95% of anything else you hear will be recognized as garbage by your ears.
The ears learn very fast and then clearly separate wrong from right. They are around 500$ a pair and worth a lot more.

Maybe look at madisoundspeakerstore.com, they have quite some nice kits. Look for those kit's needing around 12 liter or less, which should be the net volume of your cabinet. If a vented speaker has too much bass in your room, you can always close the ports with a pair of socks. This is an approved way to regulate response in critical rooms.
 
Thanks to all for the advice - great to get replies from Germany, Australia, Belgium etc. I'm in Florida, from the UK originally, recently retired electrical engineer - my career was nothing to do with audio, but I'm handy with a meter, soldering iron, etc.

@ Moondog55 I measured the Mission 70's 40 year old Bennic 4.7MFD capacitor at 24uF (please see picture), both directions the same, my meter is accurate - so yes agree the first thing to replace !. Interesting how after time it is now larger capacitance - probably the plates are now closer together as it dried out ?, increasing the capacitance.
Amazon US have a 4 pack of Nichicon ES bipolar 4.7uF 50V audio caps for $9, easy to order, so planning that route.
I removed a wire from the woofer unit, and connected the speaker back up to the amplifier, the original Vifa D19 tweeter still "works" after 40 years. Sounds clean, no "grating or clipping", though very "quiet" without the main driver. If the tweeter "works" at all, does that mean it still has ferrofluid and has not "dried up" ?, or how do I tell if it has dried up after almost 40 years ?. There is no mechanical damage and it has always been in controlled climate.
If I understand right a bigger capacitor in series with the tweeter would allow more midrange frequency signal, so maybe damaging it over time ?.
My stands are 17.5" high, with the tweeter at 21" off the floor - a bit low maybe ?, but fits my furniture.

@ Galu & TurboWatch2 Appreciate your thoughts, it's tricky when you see both glowing and damming reviews of the same speakers !, and have nothing to compare to. Yes, planning on changing the "tired" electrolytic first per above, then reevaluate.

If someone with a Mission 70 MKII could open it up, and send us the X-over schematic, that would be great. Maybe I should start a separate post ?. The original Mission 70's I have use a simple 2 component tweeter cross over. 0.22mH inductor (see picture) in parallel with the tweeter, clearly measured with tweeter disconnected, then the series 4.7uF (or in my case 24uF !), connected to the positive post. The main unit wired straight across the posts.

@ waxx Thanks for the interesting Seas link, should sound European !. The Loki maybe more the size I am interested in, will keep it in mind.

Plan of record :
1. Update one speaker then the other (so can compare) with a new Nichicon 4.7uF series tweeter capacitor.
2. I see the Peerless-D19TD05 reasonably priced at Parts Express, looks like a modern version of the OEM Vifa 19D, and thus plan on getting a pair. Unless the Tymphany D27TG35 at $10 more each would be a good upgrade using the same X-over, per Moondog55 ?. But that route unliked by Turbowatch2 if I read right ?.
3. Update crossover to Mission 70 MKII design if can get it's details.

Goal : Better sounding speakers, with not too many $$ spent if ultimately decide to buy a B&W CDM-1 SE/NT, Focal 608S, or a DIYS build. Hope of interest, and will update as task progresses.
 

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Use a decent cap.
Rated for 100V or higher, I don't know why but they work better in cross-overs
Jantzen Cross-Cap only cost a few dollars in that value and Standard only a few cents more, Solen etc have similar prices; I see no need to spend huge money on esoterica
 
If I understand right a bigger capacitor in series with the tweeter would allow more midrange frequency signal, so maybe damaging it over time ?

24uF is certainly a high reading. You say your meter is accurate and I presume you've checked by measuring another electrolytic capacitor.

Whether or not the tweeter has been compromised in some way will be revealed when you wire in the new capacitor - so hold fire till then.
 
If someone with a Mission 70 MKII could open it up, and send us the X-over schematic...

There's a wee glimpse of a MKII crossover in the photo below. It looks to be a second order capacitor/air cored inductor filter on the tweeter and a first order ferrite cored inductor filter on the woofer. Not a lot of help without the component values, but interesting to see what the difference is compared to the MKI.

Sorry I needed to post such a large picture!

1667602524177.png
 
The changing of the capacitor (best sound for the buck is a non audio film capacitor, MKP, MKC or MKT) is the only thing you should do with your old speakers.
Changing a tweeter will need a new constructed x-over, even if you still don't believe that. Such a simple, two part frequency divider is much more complicated than you think. To get along with such low part count, you need extremly carefull matched chassis. I'm quite certain the tweeter is a special construction, with lowered sound pressure, so no resistor is needed. It was only build for this loudspeaker, not taken from any existing programm. Any large speaker manufacturer does such OEM chassis for customers like Mission. Just as Mission builds speakers for others, like Denon.

Any "similar looking" tweeter which you may wish to be an exchange part, will be much louder. The result will be a hissing speaker with a huge frequncy gap or peak. You do not want to understand the concept of an x-over to keep things simple in your imagination. You are not the first one with this mindset. The resistance of a chassis is not constant over the frequency, why it is called impedance, which makes any linear thinking useless and dead wrong.

If a tweeter has lost it's ferro fluid, it may distort audible or not. Some just loose load-bearing capacity and burn up when played at party level. Some, even after many years of use, still have a functioning liquid inside. A impedance test would give some hint's.

Don't waste money on this speaker's internals, 10$ including P&P is enough. Your measurements, which sure do not show the reality (maybe you got the decimal point wrong? 2.4uF would be probable), indicate that a correct 4.7uF capacitor will notably change the sound. Listen to both juvenated speakers for a while and decide what your next step is.
Your amplifier is a nice old model, fine to look at. If you want to improve your chain try some modern D-amp in the 50-100$ region. Something like a Breeze Audio or similar will mop the floor with almost any old NAD, hard to accept, but true. Buy one at Amazon, return it when you proof me wrong. Ask here which one is the weeks favorite... Money much better spent than on some hopeless tweeter experiments. Your CD player is fine, keep it.
 
Respectfully I disagree Turbo.
I'm 70+ with a firearms induced hearing loss and tinitus and even I can hear the difference between a reasonable quality cap at $7- each and those ultra cheap Bennic and the linked larger tweeter would work fine with the existing XO if there was some padding added before it.
The D19 is a terrible tweeter and only used in large quantities because it was cheap. I think even the Audax Mylar is better.
Changing the tweeter may lead into more research and more tinkering on your part florida but this is after all a DIY form and such tinkering I consider part of the fun
 
Capacitor sound is a religious theme. We made extensive listening tests on a two way speaker with a 6dB x-over and the conclusion after all trials was quite simple: There are lot's of bipolar electrolytic that sound bad. Not all, but many degrade the sound and limit details, some even distort.
Then, beside from Chinese film types, like, you named it, Bennic, any quality industrial film capacitor sounds OK. How Bennic manages to build such bad caps may be a well kept secret.
This does not mean all film caps sound identical, but some come out different. What you can not say for sure, is which "different" is the best. Maybe the best cap only suited the specific tweeter situation best? I try to stay objective, even as this is very hard in audio.
Please accept that inside most "Audio" caps are just some kind of industry products, with a fancy case. Only a few brands really do them them in house. Please do not tell me Wima, Epcos, Siemens or GE, just to name a few, do not know how to make a good capacitor.
What was very clear in one trial and everyone agreed, a motor cap (the ones you find on simple AC motors) sounded best, compared to all the audio stuff. Looked strange, sounded great. Some paper cap.
When still available, some very rustic looking Russian and east German film caps sounded first class too.
Maybe get some surplus film caps one day and try them in a simple x-over, directly in front of the tweeter. You may be surprised that good sound does not always mean to spend a fortune on some gold plated bees wax virgin hair combination. It is not that simple like "The more expensive the capacitor, the better".

If you give advice to someone, you got to consider his persona. You and me may not have a problem to put two resistors around a too loud tweeter. We got the physic's and a box full of samples to try.
If the guy you try to help has to learn basic's first and needs to buy any resistor he experiments with, even this may come out expensive, complicated and dissatisfying.
Hardly any dome tweeter on the market will need some taming in combination with a 6" woofer in a closed box.
Very often we, in this forum, think anyone wants to spend the rest of his life in DIYS. Sometimes people only come here to get a good result and don't want week's of experimenting.

By the way, I never found any bad sounding Viva tweeter, if it was not brocken. Even in their low end industry line. They have been making very good producs for a very long time, until Tymphany took over. The "real" Vifa speakers today are made by Scan Speak in it's lower priced series. Which does not mean Tymphany products (once Peerless and Vifa) are bad, not at all!
 
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I would check if the tweeter face plate can be removed and check for any ferrofluid dry. Is there a reference at the back?

Nothing wrong with mylar. Nothing religious, they just have extra esr as the frequency is climbing and sometimes it migth be a wanted behavior according the filter and unit. Mkts are not all equal. Also some can be warm in spite of brigthish low quality mkp than can be sometimes a little harsh with a too flat response curve. The lythics leaks with aging and must be swapped when the loudspeaker are as old as the op's.