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Vifa Vivace 87
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audiolabtower
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PostPosted: Mon Oct 04, 2021 5:10 pm    Post subject: Reply with quote
The mid definitely needs a box if not enclosed itself. I think you can see a box in the second picture, it does not look as deep as the whole cabinet
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Ioannis
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Joined: 03 Oct 2021
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PostPosted: Mon Oct 04, 2021 8:36 pm    Post subject: Reply with quote
Thanks, I thought so.

What about the tube? How long should it be?

Ioannis
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audiolabtower
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PostPosted: Mon Oct 04, 2021 9:24 pm    Post subject: Reply with quote
Not an easy question, depends on the size of the box and the parameters of the drive unit, and even then you may need to tweak based on final measurements and listening.
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Ioannis
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PostPosted: Mon Oct 04, 2021 10:52 pm    Post subject: Reply with quote
The space inside is 68 liters having v type shape over the woofer. Drivers are the Vifa p25w woofer.

Nowhere in the Elektor article was any mention even of the existence of the tube!

Ioannis
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aarraamm
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PostPosted: Mon Dec 06, 2021 8:42 pm    Post subject: Reply with quote
1. Doesn't need the mid to be somehow insulated from the rest of the box? I found that the woofer is affecting very much the response in the mid band.

- The mid is proctected on the inside with a closed plastic semi-convex "cup", 15-20 cm deep, which is lightly stuffed with some wool-like fiber. At least thats how my vivace 1987s were built. The wire comes in through a hole with some kit to make it airtight.

2. the tube of the bass reflex, how long should it be? Could not find any info on that.

- I think it was said to be a matter of taste, since the length affects the end result. Mine are 12,5 cm long but if i remember well (theyre 25+years old) i made them shorter for more bass.

unfortunately i threw away the building instructions so i have no specs or folders anymore. If anyone has the specs of the vivace 1987 filter I would be very happy. Im planning to replace the damaged midtones and at the same time swapping the elcos for new ones but i dont know the value of them...
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Ioannis
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PostPosted: Tue Dec 07, 2021 11:26 am    Post subject: Reply with quote
Thanks aarraamm. The article I had was very poor in details. Indeed though, it had a shape like your description on the back of mid speaker with no details in the text.

I have a circuit of the Vivace 94 crossover. Maybe it is of use to you.

Ioannis

https://ibb.co/KzB2TCm
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aarraamm
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PostPosted: Tue Dec 07, 2021 8:38 pm    Post subject: Reply with quote
Hej Ioannis,
thank you for picture of the the circuit.
In my 1987 the mid is a vifa DM-760 so i wouldnt dare using / adjusting your circuit, that is way over my knowledge...

In the mean time; the shop in NL who sold them, is looking for the specs, too.

And if someone else has the Vifa Vivace 1987 circuit, please reply Smile
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Ioannis
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PostPosted: Wed Dec 08, 2021 9:11 am    Post subject: Reply with quote
I was able to find the very old circuit for the Vivace 87. It is not very good image but I hope you will be able to understand the parts used.

Ioannis

https://ibb.co/q5rmWCS

Last edited by Ioannis on Thu Dec 09, 2021 7:54 am; edited 1 time in total
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aarraamm
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PostPosted: Wed Dec 08, 2021 9:51 pm    Post subject: Reply with quote
thank you, again Smile

the link doesnt seem to work, though?
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Ioannis
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PostPosted: Thu Dec 09, 2021 7:54 am    Post subject: Reply with quote
Please try again. I think is OK now.

Ioannis
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aarraamm
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PostPosted: Thu Dec 09, 2021 9:35 pm    Post subject: Reply with quote
Thank you so much! now I can finally proceed Smile
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Ioannis
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PostPosted: Fri Dec 10, 2021 10:25 am    Post subject: Reply with quote
Nice! Wish you good luck and have good time in listening them!

I think (if built correctly) they are great speakers.

Ioannis
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