Up for test is the Gladen Aerospace 28mm tweeter. Product specs can be found here.
Small Signal Parameters and Impedance
Results as measured via Dayton’s DATs measurement tool. Which is a very little handy tool to have. 😉
- f(s)= 794.70 Hz
- R(e)= 3.55 Ohms
- Z(max)= 8.19 Ohms
- Q(ms)= 2.900
- Q(es)= 2.216
- Q(ts)= 1.256
- L(e)= 0.67 mH
Frequency Response and the following Harmonic Distortion measurements were taken using Dayton’s OmniMic measurement system.
The frequency response measurements below are on-axis (0 degrees) and off-axis (15, 30, 60 degrees), measured at 2.83v/1m.
To get an idea of the off-axis response vs the on-axis (0 degrees) response, I normalized the above. What you get is the relative output level of each axis vs the on-axis level.
Harmonic Distortion Testing
Maroon – Fundamental
Blue – THD
Red – 2nd Order Distortion
Pink – 3rd Order Distortion
Green – 4th order
Teal – 5th order
Testing done in the nearfield to emulate 90dB output.
Testing done in the nearfield to emulate 96dB output.
Let’s start with the build quality… impressive. These tweeters feel heavy, which one typically equates to build quality. Though, I’m not a fan of generalizing, that generalization is legitimate in this case. There is no plastic housing; these are all (some form) of metal. I’m not necessarily a fan of the large-ish gauge wire. I do appreciate no terminals (honestly, they usually just cause your cutout diameter to be widdled out even more to accommodate the wire ran to the terminal). I just think Gladen could have used a tick smaller wire here given most will have to immediately bend the wire in the install to clear whatever pillar or sail panel they install these in.
The test data shows a mighty fine tweeter. The Fs is measured at just a tick under 800hz which indicates a lower crossover point can be used; for instance, to mate up with a 6.5″ woofer (keep a check on center-to-center spacing here).
Measured sensitivity is right around 87.5dB which jives well with the Gladen spec linked at the top of this review. Linearity is pretty good with about -2/+2.5dB. These numbers seem large, but the 2.5dB delta comes from the upward swing starting above 4khz. So, while it’s not as ‘flat’ as I’d like, I’ve come to expect this kind of upward tilt in response from dome tweeters. What’s as important, if not more important, is how well behaved the off-axis response is relative to the on-axis. If you look back at the normalized plot you see the off-axis responses follow along very well. At 30 degrees off-axis, the response is down approximately 5dB at 10khz. At 60 degrees off-axis, the response is down approximately 12.5dB at 10khz, which is pretty much par for the course for a 1″ dome tweeter.
The real shining point here is the HD results. What else can I say but they are fantastic. At 96dB output the THD (blue) is less than 0.50% down to 1.5khz where it is comprised almost entirely of 2nd order distortion above 1.5khz. Above 1.5khz there is nearly 15-20dB separation between 2nd and 3rd order components. Most people would cross this tweeter in the 2-3khz ballpark, and from what I’m seeing, it’s certainly capable (though, the slope order plays an important factor here).
Bottom line: very impressive. I honestly have no idea how much these cost but the data shows a very nice tweeter. The FR could be flatter above 4khz but the off-axis response is very well maintained and the HD is exceptional.
As mentioned in the opening paragraph, I also tested the 20mm version of this tweeter here as well. Here is a comparison picture.
Additionally, I have tested the ScanSpeak D3004/60200 here. For a comparison of the two and also with the 20mm Gladen, here you go…
Here is the on-axis response of both compared directly to each other. Black is the Scan, Blue is the Gladen 28mm:
Here’s a comparison of the Scan, Gladen 28mm, and Gladen 20mm (just for the heck of it):
And the response comparison of all three. Again, Scan is black, Gladen 28mm is blue and the Gladen 20mm is red. You can see from this comparison just how linear in response the Gladen 20mm is compared to the larger sibling and the Scan (but the Gladen 20mm cannot cross as low as these other two).
PS: If you would like to help me keep up funds for testing additional drivers, there’s a little ‘contribute’ button that goes through Paypal all the way at the bottom of every page. Any little bit helps.