Are you ready to try an Air Motion Transformer Tweeter?

[framus]

Re: Are you ready to try an Air Motion Transformer Tweeter?

Hmmmm..... Well, I attached my frd file, and those are my actual measurements at 2.83V at 1 M on the tweeter axis *except for the added low frequency extending). I did not get that peak at 15 kHz. I have another sample that should be arriving today, I will have to see if it measures the same. Below the peak your measurement is pretty flat and matches mine fairly well.

Hi What size baffle are you using, and where is the tweet located? It would be great if I just got a weird sample. Meniscus Mark offered to send me a second one, so I'll probably take him up on it.

[Jeff B.]

Re: Are you ready to try an Air Motion Transformer Tweeter?

Hi What size baffle are you using, and where is the tweet located? It would be great if I just got a weird sample. Meniscus Mark offered to send me a second one, so I'll probably take him up on it.

My measurments were quasi-infinite baffle. The tweeter was placed on the floor, facing up, with a 3/4" felt placed around the tweeter about even with the flange edge. The mic was positioned on a boom, aimed down directly at the tweeter, 1 Meter above the driver. I used 8ms gating, but artificially extended the low-end response and then extracted the minimum phase.

However, baffle placement and size would have little effect at 15khz. Wavelengths at that frequency are only .9 inches long, so diffraction would not likely be playing any role in your peak.

[jclin4]

Re: Are you ready to try an Air Motion Transformer Tweeter?

Hey Jeff, what are your thoughts about this tweeter as compared to the Hiquphon OWx tweeters? Wide dispersion, off-axis response seems to be one of the strengths of these tweeters.

Reading your review of the Hiq's, you comment that they lend themselves to easy integration with other drivers, especially compared to planars (or atleast the EMIT in particular because of rising response and the potential for exaggerated detail -- hopefully I haven't misinterpreted your comments ).

http://www.ellisaudio.com/hiqcomments.htm

How easy or hard would this AMT tweet be to integrate in your opinion?

[Paul Carmody]

Re: Are you ready to try an Air Motion Transformer Tweeter?

I'm with Dennis. I have a pair, and they both show a large spike in the Frequency Response above 10 KHz. This was not too hard to tame with a contour filter. And once addressed in the crossover, the tweeters did sound quite good.

[Deward Hastings]

Re: Are you ready to try an Air Motion Transformer Tweeter?

I'd like a dipole "tweeter" that will reach down to 1200-1400 Hz and deliver a clean 100+dB, while maintaining good pattern control from there up to perhaps 8-10kHz . . . ie. a "substitute" for back-to-back Millenniums (with better pattern top and bottom). Not going to get too excited about yet another little tweety tweeter . . . there are plenty of reasonably good (and cheap) monopole domes, planars and ribbons that are fine from 2-2.5kHz on up if they're just going on a conventional two (or even three) way box . . .

[Jeff B.]

Re: Are you ready to try an Air Motion Transformer Tweeter?

I'd like a dipole "tweeter" that will reach down to 1200-1400 Hz and deliver a clean 100+dB, while maintaining good pattern control from there up to perhaps 8-10kHz . . . ie. a "substitute" for back-to-back Millenniums (with better pattern top and bottom). Not going to get too excited about yet another little tweety tweeter . . . there are plenty of reasonably good (and cheap) monopole domes, planars and ribbons that are fine from 2-2.5kHz on up if they're just going on a conventional two (or even three) way box . . .

You should have heard the BG Radia speakers I heard at CEDIA. They used the Neo 10 in a MMTMM that was dipole to 250Hz. Sounded excellent.

You know the Parts Express sells the new version of the original dipole Heil driver. It will cross at 1kHz and play loud. It sounds very good with the right crossover.

[Jeff B.]

Re: Are you ready to try an Air Motion Transformer Tweeter?

I'm with Dennis. I have a pair, and they both show a large spike in the Frequency Response above 10 KHz. This was not too hard to tame with a contour filter. And once addressed in the crossover, the tweeters did sound quite good.

That's interesting. I should be receiving another unit today. I will see if it measures the same. I don't think it's my measuring process though because the HDS, D28/2, Usher 9930, RS28a, RS28F, SB26, and SB29neo, all measured as they should have in the top octave based on what is published for those tweeters.

What distance did you measure at?

[neildavis]

Re: Are you ready to try an Air Motion Transformer Tweeter?

I'd like a dipole "tweeter" that will reach down to 1200-1400 Hz and deliver a clean 100+dB, while maintaining good pattern control from there up to perhaps 8-10kHz . . .

So build a cylindrical Heil. With 4 or more diaphragms wrapped around a cylinder, you should get plenty of low end extension and good pattern control. Cross it over to a mini-version of the cylindrical Heil that uses those small RT200X diaphragms.

Anyone care to invest in some machining services to make magnet structures? :D

[winslow]

Re: Are you ready to try an Air Motion Transformer Tweeter?

I have a stack of these still here-

http://www.kjmagnetics.com/proddetail.asp?prod=DC2

The DIY AMT might be fun to try.

[framus]

Re: Are you ready to try an Air Motion Transformer Tweeter?

That's interesting. I should be receiving another unit today. I will see if it measures the same. I don't think it's my measuring process though because the HDS, D28/2, Usher 9930, RS28a, RS28F, SB26, and SB29neo, all measured as they should have in the top octave based on what is published for those tweeters.

What distance did you measure at?

I measured at a hair over one meter. Maybe we can both measure ours free standing at one meter and see how they compare that way. And I'll be interested in how your second sample does.

[neildavis]

Re: Are you ready to try an Air Motion Transformer Tweeter?

I have a stack of these still here-

http://www.kjmagnetics.com/proddetail.asp?prod=DC2

The DIY AMT might be fun to try.

There was an article about 35 years ago in Audio Amateur that described several different magnet structures, but with strong neo magnets there are a lot more possibilities. Someday I may update that article. The grade 42 magnets you bought are just the right thickness for a very simple magnet structure that doesn't require too much metal work.

A rather poor scan of the original article is at this link: http://www.audiodevelopers.com/misc/AA_article/

Jeez, who in their right mind would still be making DIY Heils after 35 years? Uh oh :o

[JimHRB]

Re: Are you ready to try an Air Motion Transformer Tweeter?

Anyone got any progress to report on using these?

[CUtiger]

Re: Are you ready to try an Air Motion Transformer Tweeter?

Nope- you can use these to 2kHz, Lowell. $78 though.

I'm interested in the next model down, as it's good to 3kHz and is only ~$45.

Later,
Wolf

Where can one find this model? The only thing I see listed at meniscus is the 4001.

Edit:

Nevermind found it, always forget about our friends north of the border. Now a better question has anyone measured / listened to one, hoping it is similar to its brother in this thread.

[neildavis]

Re: Are you ready to try an Air Motion Transformer Tweeter?

Edit:

Nevermind found it, always forget about our friends north of the border.

Meniscus carries the RT20021--they just don't have them listed on their web site yet. Got two for Christmas, and when I enquired they had a total of 4 but where planning to get more.

Mine are still in the box. Looked at them, but that's as far as I got.

I think there is a lot of potential in using small Heil drivers that still hasn't been explored. I made a "mini-Heil" over 35 years ago, and I've been interested in getting back to explore that potential ever since.

[CUtiger]

Re: Are you ready to try an Air Motion Transformer Tweeter?

Thanks Neil, I'll be awaiting your impressions after you get a chance to get them out of the box. Quick question are they really as tiny as listed, the PDF is hard to read but looks like the frame is 75mm? Need a tweeter to pair with a dome mid and was previously looking at the neocd1.0 but this has got me interested.