Ribbon tweeters

Docfoster

Spent 24 hours earlier this week getting excited and insomniacised about building / budging some new speakers. Basically scaled up Magisters based around 18 inch Goodman's 18P woofers (I have one already and another available...). Possibly with some ribbon tweeters...
Then realised I couldn't possibly house another pair of speakers like that. "Waste" of time and money.
So I have contented myself with fiddling with the Magisters. Logically stupid as they sound great. But...
I've had a ribbon tweeter itch that I've been wanting to scratch. Have ordered a pair to stick in the Magisters. The digital high-shelf in JRiver makes integration very doable (I hope).
What should I expect from the ribbons...?

cj66

Bows?

uglymusic

Docfoster

Ok. So that's the test track sorted.
...And the ribbons arrived yesterday. Exquisitely wrapped... ;-)

Managed to chuck them in to the magpies before leaving for a weekend in Weston.

In the 5 mins I had to listen, they sounded different (lighter?) in a sufficiently promising a way to warrant further fiddling when I get back. They are a lot more sensitive (rated 98dB), so making the digital high shelf somewhat more drastic was necessary. Continuing to tweak the perameters to find the sweet spot is something I'll get on with when I get back.

Edit...these are the ones I went for. They've halved in price of late, so I paid only £48 for 2 new ones.
https://www.monacor.com/en-gb/monacor/products/components/speaker-technology/hi-fi-tweeters/rbt-95/

Docfoster

Well they're in properly.

Physically, no great problems. The face plate of the tweeter is more or less the same size as the Monacor 19SU domes that came out. The rectangular cut out was a different shape (80x40) to the circular one I cut for the 19SUs, so I had to cut a bit at the top and bottom of the existing hole.

Specs-wise. Huge difference (98dB v 91dB) so much fiddling gone on there. All done digitally using the JRiver high-end shelf (dB level, frequency and steepness of curve). Absolutely no way I could have attempted that on the speaker crossover itself given my skills. TBH hard enough doing it by changing numbers in a PC window! It reminded me of setting up a TT when the various parameters interplay with each other meaning that tweaking one can mean having to go back and tweak others in an endless spiral of ever-decreasing circles.

After a few hours of fiddling about I can report a difference in sound. :-/ In some ways better (more precise somehow, and smoother) in other ways worse (slightly strident at times or possibly just revealing). I'm not sure it's where it should be yet. Will return to my labours when my ears have recovered some freshness.

  

Docfoster

Just realised I can calculate the curve as a start point more accurately using on line tools.
:-)

Docfoster

Decided to try basing high-shelf curve on the 12dB / octave curve of the Magister's crossover.
Turns out this is 0.7071.
Not exactly sure why using a high-shelf curve that's the same as that used in the speaker's crossover has progressed things sonically, but it has.
Final tweaks to the dB cut and to the midpoint Hz feel less like shooting at fish in a barrel now. So hopefully will reach a conclusion soon. :-)

Edit: not sure where I saw the 12dB crossover thing about the Maggies. Maybe I made it up. Or maybe I did see it somewhere...
The RBT95's are recommended for 12dB crossover slope at 5kHz, so maybe that's why those figures have been helpful in setting the high-shelf. Tho also I seem to remember that I chose the RBT95's because I knew those figures fitted with the Maggies crossover ratings. So maybe it hasn't all been just a lucky happenstance... ;-)
Clearly my memory is shit. That is undeniable.

Docfoster

Sound pretty much sorted.
Happy bunny. :-)

Docfoster

I think things are as they should be now.

I'll post more about the general process elsewhere in the thread on the Maggies.

Now they've been properly integrated, my thoughts on the ribbons Monacor RBT95 specifically are that I prefer the sound of the system with them to how it sounded with the 19SU. There is a preferable smoothness and what I think is called "brilliance" to the sound from the upper midrange upwards. Things sound cleaner. A bit like a lesser version of the difference between Class A and Class A/B. Female vocals benefit especially. Percussion instruments (cymbals especially) are better defined tonally and spatially. I think there might be a knock on effect to the bass somehow, as my brain is telling me that bass drums and guitars are also better defined.

Once caveat to this: I did not pay as much attention to the slope of high shelf curve when fitting the 19SU tweeters, so their contribution may not have been fully optimised. So comparisons not completely fair. Please don't make me go back and do it again with them...!

[-O<

And a couple of final points:

1. It's worth noting that the RBT95 ribbon tweeters may only be able to help out in a 3 way speaker systems as their recommended crossover point is 5000Hz. This is spot-on for the Goodmans Magisters, but the tweeter crossover point for 2-ways is usually much lower than this AFAIR.

2. The RBT95 are very sensitive (98dB). So there won't be many speakers that they can just be dropped into without some crossover adjustments (e.g. L-pad) or high-end shelving in all-digital systems such as mine.

uglymusic

Yikes! How crazy is all that?

I'm glad you're having fun, Ben!