Technocracy - Технократија (Seas, Morel, Visaton)
Hallo zusammen,
Ich spreche kein Deutsch, also werde ich in Englisch schreiben
But i'll try to learn some in the future. A member from this forum (Mathias) recommended me to come here and certainly there's lots of interesting stuff to read so i feel obliged to give something to the community as well.
In the past i've tried the same tweeters with and without ferrofluid and noticed that ferrofluid lowers Fs, cools down the voice coil and few other things but at the expense of blurring some fine micro-details. In the past 15 years i totally forgot about tests i made until recently - when a guy i now sent me a pic of D2608/913 opened and said that the ferrofluid was taken out. I immediately started thinking when will i have some time to do the check if it can be done safely with my Morel DMS30S. Few months ago (while kids were sleeping and wife reading) i managed to do it. As ferrofluid can be bought on ebay these days so what's the worst thing that can happen - to change the old ferrofluid?
Getting it out was a fairly easy task but with certain level of caution and care while opening it. Simple peace of toilet paper was enough to soak the ferrofluid from the magnetic gap. I had a problem earlier of one tweeter being slightly less sensitive than the other. When i opened it, it was obvious that one tweeter had healthy amount of FF but the other not so much. It could evaporate a little during time and maybe thickened a little bit. Anyways, here are the measurements before and after removing the ferrofluid from the gap.
https://s7.postimg.org/ewppsy4u3/image.png
https://s7.postimg.org/yekd8vu23/image.png
https://s7.postimg.org/mcozer097/image.png
What was the result of this stunt ? It was clear after first few tones that it is better. The only way to explain is that metal instruments started to sound metallic. The details appeared. Seas makes tweeters with prefix NoFerro and of course without ferrofluid - and for a good reason i guess. Not that i think that all tweeters are better without ferrofluid - but there is something to it. It was also clear, after the first few tones, that the crossover i made before was nothing less than obsolete or a good starting point for a new one. The tweeters started to measure the same, sensitivity wise. So few changes were in order and it lead to next few measurements.
On axis
https://s7.postimg.org/4dpq3jp8r/na_osi_1.png
On axis, 1dB grid
https://s7.postimg.org/r7e2zc6mz/image.png
Reversed phase
https://s7.postimg.org/4iovzr9tn/image.png
Individual driver response 2dB grid
https://s10.postimg.org/ki92tdtp5/image.png
Off axis 1
https://s13.postimg.org/kzlqpm0x3/van_ose_1.png
Off axis 2
https://s13.postimg.org/ka2yd983b/van_ose_2.png
Measurement at 1m vs 2m distance
https://s7.postimg.org/w61ldv2q3/1_2.png
All measurements are done from 1m distance except the last one that serves just to see if the response changes significantly. There are measurements on axis, off axis 90 degrees and everything in between is - well somewhere in between. I didn't make the jig to see at what angles exactly i'm measuring it - it serves me to see that there is slight blooming at 3.5KHz but not too bad. They all are over 50deg - from 0-45 they look ridiculously good. Slight blooming at 3.5KHz is the reason i didn't want to sort out the slight 1dB dip on axis at 3.5KHz - i think it will make for nice and flat power response. That would be my graphs for now with all of their highs and lows.
Crossover
https://s9.postimg.org/kjbek5bvj/image.jpg
Distortion for L15RLY
Burst decay for L15RLY
Mounting the tweeter on the waveguide:
https://s1.postimg.org/6go01gszj/DSC_0020.jpg
https://s1.postimg.org/fe8pytlfj/DSC_0015.jpg
https://s1.postimg.org/uggcvrglb/DSC_0011.jpg
https://s1.postimg.org/gbf57owxr/DSC_0012.jpg
https://s1.postimg.org/k92ex3jr3/DSC_0013.jpg
Test cabinets
https://s9.postimg.org/w2qi79inz/attachment.jpg
https://s24.postimg.org/utmj3ffph/DSC_0010.jpg
Finished cabinets:
https://s1.postimg.org/1hm0ml7nen/Seas_5.jpg
https://s1.postimg.org/5bus5jry7j/Seas_6.jpg
https://s1.postimg.org/7pa60x1c5b/Seas_7.jpg
I added piece of pipe at the inner end of Visaton BR19.24 bass reflex tube. My measured impedance of finished loudspeaker says that Fb is 45Hz.
Volume of my loudspeaker cabinet is 13.6 liters without tube and volume occupied by drivers and damping material. If i ever use them with subs, i'll put them in smaller closed cabinets.
Pretty low xover point made the breakup quite irrelevant. This is a full baffle step design with F3=45Hz so corners are out of the question but they don't mind being close to rear wall. They sound great to me but (unless used with subs) they are not for large rooms. Mine is about 20sq meters. If you bought it long time ago (like i did) for whatever reason and it sits unused somewhere, you should try this. You just might be surprised.
Enjoy,
Zvu
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