# Critical Mass Audio T1a titanium



## npdang (Jul 29, 2005)

I'm sure we've all heard of Critical Mass audio, creator of the infamous high performance (if not somewhat controversial) UL12 subwoofer. Thanks to MSimz, who graciously donated a T1a tweeter (retail $227), let's see how well their tweeters perform.

First, a picture. It's the tweeter with the lead wires running out, sitting next to my reference compact tweeter the Seas neo aluminum dome.










The version I received is a 1" (what appears to be a titanium or aluminum dome) rather than the silk dome pictured on the website, neo motor in a surface mount cup. The tweeter is extremely compact, but the packaging I received did not allow for easy flush mount. There is also a large diffuser on the front of the grille, to improve the off-axis performance. Although you can't tell from the photo, the dome profile is extremely flat, which in my experience tends to mean great off-axis response. I did not notice any chambering in the rear of the tweeter, which would be indicative of a high fs driver.

First, a distortion test. I set the level at about 1% THD for our reference the Seas neo, and adjusted the output for the T1a to match. It appears the T1a is noticeably less efficient than the Seas, perhaps given it's slightly smaller size.

Seas:










T1a:










Looking at both plots, the T1a should ideally be used above 4khz. Distortion rises sharply below that point, as does the response begin to drop. There's also a noticeable peak centered between 15-20k, indicative of traditional titanium dome tweeters. Subjective tests confirm that distortion is highly audible when driving the tweeter too low, too hard. There is definitely a confused, hashy sound that even a casual listener would be able to discern. While I found top end dispersion to be excellent, there is noticeable sharpness and edge to the sound that you find typically in drivers with peaky on-axis response. A better option is to find a tweeter with a highly optimized waveguide that improves the off-axis response without introducing peaks or rising response on-axis, or to simply use a smaller diaphragm design.

Distortion in the upper frequencies is also audible (and reaches nearly 10% in some cases) at the same output as the Seas is hovering at 1% THD. Whether or not you will be able to "tell", would depend heavily on the listening environment, source material, and personal level of accuity. 

For the person who desires the absolute best top end extension even at the most extreme listening angles, you would be hard pressed to do better than the Critical Mass T1a. Other similar options such as the Adire Koda tweeter, or the Peerless RDC spring to mind as well. Unfortunately the high price tag, poor distortion performance, and edgy top end come as downsides with the T1a.


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## [email protected] (Jun 12, 2008)

npdang said:


> the dome profile is extremely flat, which in my experience tends to mean great off-axis response.


nice write up, but I would have to disagree with this statement, I think the shallower the dome the sound is more directional, the higher the dome goes the more is disperses the sound, that is why shallow domes have something to HELP disperse the sound, taller domes do not


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## camojoe (Jan 23, 2007)

npdang,
Just checked this section and found your new reviews. This made me . I really enjoy your reviews and respect your comments and opinions. I know you've heard it before but,thanks for all your hard work. Well, gotta get back and read them...again and again and again.


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## Kmanian (Apr 8, 2008)

nice review, I actually have them installed in my Ram, I am enjoying them although they do suffer from some of the points you have made. I have been messing with the tuning and am finding a nice middle gound with them. I think they are going to workout nicely.

and thanks for the work also.


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## GLN305 (Nov 2, 2007)

I owned a set of these, but they were different than the ones you tested. Mine seems like a metallized cloth of some sort, not sure how to explain it. They sounded really good when I replaced my JL ZR tweeters with them, much better than the ZR tweeter I must say. They seemed to have a balance of the good properties of a metal dome and cloth dome. I am thinking that they must have changed since I had mine.


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