Anyone looking to use Hygeia (Airborne) AMT tweeters in their designs?

[OscarS]

I might order a couple more next month. If anyone wants in to consolidate into one shipment, just let me know.

[ilardi]

I would definitely like to order a few. Mostly for a home theater system but also for a stereo system. But before I tell you which I want I have a question and I am hoping that you (OscarS or anybody else with experience with these drivers) , based on your experience with the drivers might be able to answer so that I can decide which ones to order. Specifically I am wondering if there is much "tonal" difference between the RT-5002 and the RT-4001. I am space constrained for my LCR so that it will be difficult to use the the RT-5002 in that position, but I would still like to use the RT5002 for the left and right channels since they seem to have lower distortion and other advantages. Based on your auditioning of the drivers (I have never heard them) do you think there would be much difference in tonal/sound quality if I were to use the RT-4001 for the center and the RT-5002 for the left and right channels?

Thanks in advance for your advice.

[OscarS]

Originally Posted by ilardi

I would definitely like to order a few. Mostly for a home theater system but also for a stereo system. But before I tell you which I want I have a question and I am hoping that you (OscarS or anybody else with experience with these drivers) , based on your experience with the drivers might be able to answer so that I can decide which ones to order. Specifically I am wondering if there is much "tonal" difference between the RT-5002 and the RT-4001. I am space constrained for my LCR so that it will be difficult to use the the RT-5002 in that position, but I would still like to use the RT5002 for the left and right channels since they seem to have lower distortion and other advantages. Based on your auditioning of the drivers (I have never heard them) do you think there would be much difference in tonal/sound quality if I were to use the RT-4001 for the center and the RT-5002 for the left and right channels?

Thanks in advance for your advice.

It's hard to say because, I don't know know about everyone else, but I can't really audition just a tweeter by itself, it has to be implemented with a midrange below it (or midbass, or woofer, or whatever). I think it's because my brain is too hard-wired to hear guitar, which is my forté. My brain wants to hear a full range guitar signal, and when it doesn't it goes into blue-screen error mode, lol.

What I can do for you, however, is take FR and distortion measurements of the 4001 so you can compare them to the RT-5002. I can tell you for sure that it won't go as low simply because of the smaller size, but I'm sure you already know that.

In-room FR (including reflections) of the RT-5002:


Distortion measurement of the RT-5002, in-room, mic 1" from speaker. Graph only goes up to 10k by default.


I should be able to take some measurements of the 4001 soon. The nasty 2nd/3rd order harmonic distortion peaks is due to the ever so tiny resonance of the folded membrane. Yup, even these cannot escape Mother Nature. I'm going to try and tame it with a notch filter to see if it helps.

[ilardi]

Thanks so much. I agree, I also can't audition a tweeter by itself. I look forward to seeing the your measurements.

[OscarS]

Allow me to clarify a few things.

• You wouldn't actually be buying from me, so I can't accept paypal payments. The manufacturer in China only accepts bank wire transfer. That is how I placed my initial order last October ($428).
  • Luckily on that order, I wasn't hit with any US Customs Import Duties/Fees. Talk about being worried about a lot of money being sent overseas with no recourse to retrieve it should something go wrong.

• The timing is very long. It took them nearly 3 months because they had to order some faceplates. Hopefully they have them in stock this time around, but I don't know as I'm not there at the factory.

• So while yes, you'd have to send me the money (assuming you want in on a consolidated order together with mine) in a non-paypal form so I could then send it to them,
  • I can't be responsible for your cash should you get impatient/worried/whatever and then want to file a paypal claim against me. I won't be going that route what so ever.
  • Obviously this buying opportunity isn't for everyone.
    • If I wasn't such a nice guy, I could have kept all this to myself from the very beginning anyways, because I did all the work. I don't need anyone to participate in this purchase with me at all to "make it happen", I buy/order my own things at will because I can. I will order my own things regardless if zero people want to order along with me.

• If you want to order them yourself and do your own wire transfer, I can give you their email. But let me warn you, it is a lot of work.
  • Their English and overall communication is horrible..
  • They sometimes check their email only once every 2 weeks.
  • Their English and overall communication is horrible.
  • They couldn't even answer me in simple words if they had received my bank wire transfer. <--If that alone scares you, then this isn't a purchasing opportunity for you.
  • But they did email me confirmation when the order was sent, and they did come through.
  • Their English and overall communication is horrible.
  • Would it have hurt me significantly if I had lost all those $428? Not really. Sure it would suck a&# if I had, but I don't see it any different from having wasted that much on a previous relationship that didn't work out. How much money do we lose wining & dining our [now] ex-gf/ex-wives/etc? A lot, I bet. Do we recover? Sure. That's how I see it and my own personal approach when evaluating these kinds of "risks".

So like I said, maybe this isn't the group buy for you if you feel "risk". I do have faith in the vendor, and I will place my order regardless, just as I did this past October.

[joetekubi]

That distortion looks pretty good - looking forward to the 4001 graphs.

[OscarS]

Here is the in-room frequency response (including room reflections) of the RT-4001, with ~1W input. 2.15V into 4.5 Re.


I should have the distortion graph maybe this weekend. Something was off so I wasn't trusting the measurements I was getting (too high), and replicating the graphs of previously measured drivers were also off, so I have some troubleshooting to do.

[OscarS]

Finally replicated a previous measurement, so here is the rest of the pending info.

RT-4001 Harmonic Distortion




RT-20051 Frequency Response, ~1W/1m, including some room reflections.



RT-20051 Harmonic Distortion







For those who might be interested in the RT-50021, here is a measurement I did tonight together with those depicted above. I used a modified Parts-Express H110 Horn mounted to the RT-50021 with it's faceplate removed. Huge increase in midrange output.

Blue stock, Red w/ modified Horn.

[OscarS]

Also just for the heck of it, I took the raw THD data from the decibel curves and converted them to percentage here. With the exception of that mechanical/electrical resonance, a pretty low distortion driver. Oh, and no filtering within the shown window. The only filter I run when running sweeps on tweeters is usually about 350Hz, so it doesn't affect these measurements.

[OscarS]

Distortion measurements for the RT-4001 and RT-20051.