Microbe XT crossovers

[NdG1977]

Hi guys,
Anybody has experience with the Microbe XT?
I found only a few threads about them, they look promising...

Also, anybody has the crossovers? all those post were old and the pics were not visible any more.

Thanks!

[Wolf]

http://www.hifi-forum.de/viewthread-205-397.html

I didn't have the graphic, but someone else built them...
Wolf

[Wolf]

http://www.htguide.com/forum/showthr...crobes-I-built

And more info..
Wolf

[Wolf]

Did one better via archive.org:
https://web.archive.org/web/20180117...crobes-I-built



Found it for you!
Wolf

[NdG1977]

Thanks Wolf! Very appreciated!

[NdG1977]

I can get the XT25TG30-04 or XT25BG60-04 (Double magnet) for the same price of the XT25SC90-04.
Would you suggest to go for one of those? Which one would fit better in your opinion? I still have to try a crossover, but it doesn't look like it's a difficult tweeter.
I was planning to build and tune the crossovers anyway, so with some help from the forum I'm confident I can sort it out...

[Chris Roemer]

I'd use the SC90 if you want them to sound like Roman's Microbes.
If you don't, I'd prob'ly go w/the TG.
While it should sound (slightly) different, there's not much you can do to the XO to compensate. I'd leave it "as-is".

[NdG1977]

Tough decision...If you look around seems clear that the other 2 are superior tweeters probably the 60 is the best? I haven't listened to any of them...The problem is that any pair would cost me the same... feels stupid to buy the chep one! I can always buy both and compare...I'll do that...I hate you guys...

Getting back on topic: Roman writes in the original Microbe: "The Microbe uses a 4th order Linkwitz Riley crossover with a crossover frequency of 3200 Hz." What does it mean? To me it looks 2rd on the woofer and 3rd on the Tweeter (Electrical)...what am I missing? Is he talking about acoustic order? (probably yes) If that's the case the tweeter is more than 12db/oct but still far from 24...Not complaining about Roman write-up, it's about my ignorance...

[Wolf]

Yes- acoustic rolloff/order.

Most of the time, tweeters have an inherent 12dB/octave slope being that they are typically sealed systems. With the additional elec 2nd order (sometimes third) on the tweeter, this yields a 4th order rolloff. The step to third would be to add additional phase rotation to align well with the woofer's phase due to the non-coincidental arrangement of drivers and their inherent acoustic offsets.

EDIT/Also of note: Just because you have a 12dB rolloff and 12dB xover does not mean they will sum to 4th order. Some tweeters have extraordinarily wide bandwidth, and it takes more than the 12dB added to actually yield the 24dB/octave rolloff.

Also- I would not discount the XT25SC90, as it sounds great! All of the XT tweeters sound really good, and used within their happy place, they are world-class performers.

Later,
Wolf

[NdG1977]

AH! ok...clear! It all make sense when explained...
In another post you mentioned a guide to crossover design you wrote. I cannot find it, also because the blog doesn't work very well, a lot of posts are just empty.
Do you have a link? I'm currently mixing basic academic competence with random websites guides and speaker books...they all make sense, but joining the dots is not always easy! ah, SW tutorials, some great and some made by people with less experience than me...I guess...

I'm not really fixed on the Microbes XT, but seem to be a nice compromise. main issue would be that it is a pretty old design and from what I've seen the specs of the RS125 have changed quite a lot during the years (Thanks Chris - another post). I'm expecting to have to tweak it a little bit to get the right response.
I suppose I'll build it as it is and then measure it and decide...
I looked at your designs, but they all come up too expensive consider that the Beston tweeters alone would cost more for shipment than parts! EU stuff is cheaper here. I'll keep the scandivifas for when I'll know what I'm doing! starting cheap...

Sorry mate...a lot of questions!

[Wolf]

Where are you located? Just curious...

As to the 'tips' blogs, I'm not sure I still have them. When the blog profiles/posts disappeared with a software update I think I lost what was uploaded.

I'll have to see if I can locate them in a file somewhere, but it's not likely.

Later,
Wolf

[NdG1977]

I’m in the UK...close to Manchester actually. Imports at the moment are kind of “disrupted” here
If you find them let me know! I’d be interested in reading them!

[evilskillit]

Wolf, thanks for digging up that crossover diagram from my old post. I happened to be passing by and was going to jump in this thread to help out, but I see you already beat me to it.

Amusingly a few months ago, about a decade after that post I finally got around to building some better cabinets for the Microbe XT's. The more things change the more they stay the same, my camera is still crap.