Alternative drivers

Posted by: Jeff_in_the_D

Alternative drivers - 08/07/17 07:24 PM

I have not been around this forum as long as some of you have. Does anyone recall there being discussions concerning implementing different types of drivers? Such as ribbon tweeters for instance. I personally have only heard one brand of speaker that utilizes ribbon tweeters. I liked what I heard. Perhaps Axiom might consider ribbons as an option? Just a thought.
Jeff
Posted by: bridgman

Re: Alternative drivers - 08/07/17 09:43 PM

There were some discussions about soft-dome vs metal tweeters maybe 10 years ago, and a "your woofers look wimpy" discussion more recently that might have encouraged work on the HP bass drivers, but I don't think I have seen any discussion on ribbon tweeters. There was at least one board member running external super tweeters with his Axioms (2x6spds ?) but those were piezos IIRC.

I would like to try some speakers with the RAAL tweeter and occasionally think about picking up some Sierra Towers with the RAAL upgrade...

... but I keep having to do other things with the money - and besides, I am disgustingly happy with my M5HPs right now, after spiraling through M60s, Sierra-1s and M3s first.

I guess I could upgrade my Sierra-1s to Sierra-2s, but it might be more fun to just buy the tweeters and start a forum thread for hacking the M60 crossovers to work with them.

That would make for a fun GTG when the work was finished smile
Posted by: bridgman

Re: Alternative drivers - 08/08/17 12:33 AM

The one residual concern with ribbon tweeters is comments like this...

Quote:
I've yet to meet a ribbon tweeter that does not require your head to be in a vice to really maintain the sweet spot.

... basically very little dispersion, particularly vertically.

Probably not an issue with bookshelf speakers where raising & lowering to match your ears is as simple as changing stands (the tops of my M5HPs are somewhere around 47.5" off the ground) but more of a challenge for towers where you need to get into raising the front legs & tilting them back.
Posted by: 2x6spds

Re: Alternative drivers - 08/08/17 01:47 AM

Ribbons are difficult to integrate with the drivers. The Axioms enjoy a pretty seamless integration throughout their frequency range.

I had a Merak center channel, don't recall the designation, twin 6.5" and a 0.75" Titanium tweeter. Swapped in a pair of Axiom aluminum 6.5s and cobbled a tweeter/capacitor from a Reference de Capo 3a I found on ebay in place of the Axiom Ti tweeter. The Reference 3a did not use a cross-over, much like the Axiom M3s, just a cap and a resister, allowing the driver to mechanically roll off where the tweeter picks up. It's actually a stunning sounding speaker.

I modified some Radio Shack super tweeters with Solen caps. I think they help. Dogs love 'em.
Posted by: AAAA

Re: Alternative drivers - 08/08/17 04:15 AM

Ribbons need to cross over a bit higher than normal tweeters. They only make sense in true 3 way designs. I recently built some speakers that used ribbons from a design at speakerdesignworks.com The result was pretty good.
Posted by: bridgman

Re: Alternative drivers - 08/08/17 11:05 AM

Originally Posted By Serenity_Now
I recently built some speakers that used ribbons from a design at speakerdesignworks.com The result was pretty good.

I can't believe I missed that, thanks for the reminder. I must have been spending too much time admiring the cabinet pics you posted.
Posted by: Ian

Re: Alternative drivers - 08/08/17 12:10 PM

Hi Jeff,

We have played around with both Ribbon and Planer-magnetic tweeters but have not found any good reason to consider using them. Maximum output before compression can be a problem with these designs and the off axis response lacks uniformity. If you are in the camp of wanting your tweeter to operate out to 40kHz and beyond then a Ribbon tweeter crossed over as a Super-tweeter would be a good thing to do. I have run tests with this in the past and did not find any reason to be concerned with the response out to 40kHz.
Posted by: Jeff_in_the_D

Re: Alternative drivers - 08/08/17 03:44 PM

Thank you Ian for sharing your thoughts on this. Your response is greatly appreciated.
Jeff
Posted by: Jeff_in_the_D

Re: Alternative drivers - 08/14/17 12:26 PM

Hey SN, what was the name of your speaker building thread.
Thanks Jeff
Posted by: bridgman

Re: Alternative drivers - 08/14/17 12:58 PM

Originally Posted By Strider53
Hey SN, what was the name of your speaker building thread.
Thanks Jeff


Somewhere around here or a few pages back...

https://www.axiomaudio.com/boards/ubbthreads.php/topics/425662/33

... although looks like PhotoBucket is being difficult.

The image from Princess Auto still displays OK though
Posted by: Jeff_in_the_D

Re: Alternative drivers - 08/27/17 11:33 AM

With my somewhat limited experience with speakers utilizing a ribbon tweeter I have not found this to be an issue, this "head in a vise" scenario. Perhaps because the full range, three way towers I have listened to are approximately 44" inches tall? IDK, they are quite wonderful sounding. I do realize everyone's experience can/will be different .
Jeff
Posted by: AAAA

Re: Alternative drivers - 08/27/17 06:59 PM



Hi Strider. When photobucket stopped 3rd party hosting my build thread was pretty much gutted. The last dozen pages or so in the thread Bridgman linked pertain to the speakers. Here is a pic of how they turned out. I built three as an LCR set for behind our screen wall. Pretty nice for movies.
Posted by: Jeff_in_the_D

Re: Alternative drivers - 08/27/17 08:04 PM

Serenity Now, wow they look great! Hope they sound as fine as they look. What ribbon tweeter did you use?
Jeff
Posted by: brwsaw

Re: Alternative drivers - 08/28/17 12:43 AM

They look great
Posted by: bridgman

Re: Alternative drivers - 08/28/17 02:12 AM

Originally Posted By Strider53
Serenity Now, wow they look great! Hope they sound as fine as they look. What ribbon tweeter did you use?

It's disturbing that I knew the answer from memory (I really enjoyed the build thread), but IIRC according to the plans it is this one .

It occurred to me that the degree of "head in a vice" behaviour would probably be a function of the mid-tweet crossover frequency, but it's too late at night for me to remember whether higher or lower is better.
Posted by: AAAA

Re: Alternative drivers - 08/28/17 03:49 AM

Yeah that's the one.

In this design it was crossed at 3500hz I think to the Mids. I think the designer uses a rule of thumb of filtering a whole octave outside of the drivers "safe" range. I think the tweeters could be crossed at 2500hz according to the manufacturer.