Announcement

Collapse
No announcement yet.

Are you ready to try an Air Motion Transformer Tweeter?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

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

    Originally posted by Jeff B. View Post
    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.

    Leave a comment:


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

    I have a stack of these still here-

    neodymium,magnets,strong,magnetic,magnet,neo,rare,earth,NIB,supermagnet,neodymium magnets,NdFeB,permanent,powerful


    The DIY AMT might be fun to try.

    Leave a comment:


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

    Originally posted by Deward Hastings View Post
    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

    Leave a comment:


  • Jeff B.
    replied
    Re: Are you ready to try an Air Motion Transformer Tweeter?

    Originally posted by Paul Carmody View Post
    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?

    Leave a comment:


  • Jeff B.
    replied
    Re: Are you ready to try an Air Motion Transformer Tweeter?

    Originally posted by Deward Hastings View Post
    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.

    Leave a comment:


  • Deward Hastings
    replied
    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 . . .

    Leave a comment:


  • Paul Carmody
    replied
    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.
    Attached Files

    Leave a comment:


  • jclin4
    replied
    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 ).



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

    Leave a comment:


  • Jeff B.
    replied
    Re: Are you ready to try an Air Motion Transformer Tweeter?

    Originally posted by framus View Post
    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.

    Leave a comment:


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

    Originally posted by Jeff B. View Post
    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.

    Leave a comment:


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

    Ruler flat impedance means easy crossovers. My case with the Neo-8S and the RT-2002 three components- .08mH coil, 15uf capacitance, and 1 ohm resistor wired in AR style series XO.

    Leave a comment:


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

    Originally posted by winslow View Post
    I have been using the RT-20021 for a couple of weeks now on top of some BG Neo-8Ss in my car. I think it's a perfect match. I am not missing the Scan D3004/6020s that was in there before..
    I used to have DIY Heils in all of my cars, going back to the mid-70's.

    I think the next step up from a Heil is an omni-directional Heil. I've had an omni Heil in the project queue for several years now...just haven't had enough time to finish it off. But I'm going to retire at the end of the year, and start working off that long list of projects...

    Leave a comment:


  • fastbike1
    replied
    Re: Are you ready to try an Air Motion Transformer Tweeter?

    I had a pair of AMT1's and absolutely loved them. "The Boss" ordered me to get rid of the monoliths when the first baby got mobile. Fortunately I had the sense not to ask if I could which went.:D

    I'm very interesting in these new ones because the AMT1 still stick in my mind as filling the room with music.

    Originally posted by JimHRB View Post
    Interesting. I heard the original ESS AMT3 "Rock Monitors" back in the 1970s and was very impressed. They were 3-way towers with the dipole AMT on top. I still have the brochure in my file cabinet.

    Leave a comment:


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

    I have been using the RT-20021 for a couple of weeks now on top of some BG Neo-8Ss in my car. I think it's a perfect match. I am not missing the Scan D3004/6020s that was in there before..

    Leave a comment:


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

    Originally posted by neildavis View Post
    I'll post some pictures tomorrow.
    This is what an unfolded and folded RT200X diaphragm look like:


    The RT200X is smaller than the RT4001 that Jeff described. The RT5001 is the larger sibling. This is the unfolded RT500X diaphragm:


    I used the pre-folded ESS replacement diaphragms for the larger cylindical Heil. Don't ask how it sounds, because it isn't done. You can see the large neo magnet sticking out the bottom. The magnet is actually 5 slugs glued together.



    It's nerve-wracking to work on these, because I need to curve each plastic frame using a fixture that gets heated with a blowtorch. Heat the metal, then tighten the screws. It's odd using a blowtorch around a $60 plastic diaphragm, but sometimes you gotta do what you gotta do. I've got 2 assembled to the interior of the magnet structure--still need to finish two more and then assemble the outer structure.


    The magnet structure is described in detail in this thread:


    It ain't DIY unless you cut your own steel :D

    Leave a comment:

Working...
X