Ascendant Audio Atlas 12" vs. TC Sounds Tc2+ 12"

[npdang]

Pics of the subs:

http://diymobileaudio.com/pics/75d89d9f.jpg
http://diymobileaudio.com/pics/729a2248.jpg
http://diymobileaudio.com/pics/3a2c2efc.jpg

Build Quality + Aesthetics:

Personally, I think both of these subs are amazingly well built for the money. Both subs feature all the amenities you would expect from a high end sub such as heavy cast frames, foam surrounds, push terminals, and a rubber gasket.

The Atlas has a somewhat nicer, chrome back plate and 12 spoke basket, venting under the spider, and of course a dead giveaway for an xbl^2 motor... the large nearly 1" chrome top plate. The cone also appears to be made from treated paper/kevlar with a carbon fiber dustcap glued on top.

The Tc2+ has sewn in tinsel leads and Imho, a nicer looking aluminum cone. The 4 spoke basket and no venting under the spider gives it a somewhat more rugged, if not dated look.

Nearfield(taken at 1" from the driver's cone) Frequency response:

Green = TC2+
Blue = Atlas 12" with second voice coil shorted (low qts configuration)

http://diymobileaudio.com/pics/tcatlas12fr.jpg

This was very interesting. Given the manufacturer published specs, I would have expected the Atlas to have a more extended top end as well as noticeably higher efficiency. It clearly doesn't, and plots almost identically to the Tc2+. I have no explanation for this, as the inductance for the Atlas 12" is given at .86mh as compared to the tc2+ measured rating of 4.8mh @ 1khz. Also, seeing as the tc2+ was measured at 85.1dbwm, I would expect the high/mid qts configurations of the Atlas 12" to have an efficiency that makes the driver almost unusable.

Non-linear distorion performance:

Nearfield(taken 1" from the cone) measurement, drive level 20V rms(~100watts into 4 ohm nominal load), swept sine wave 20-100hz.

TC2+

http://diymobileaudio.com/pics/tcsweep.jpg

Atlas 12"

http://www.diymobileaudio.com/pics/atlassweep.jpg

Again, another surprise. The Atlas 12" has very audible rub/buzz/tinsel lead noise. The TC2+ is nearly dead silent. This was shocking, given that the Koda 10" I had tested almost 6 months back was a dead silent performer as well.

Looking at the harmonic distortion plots, the Atlas 12" has better 3rd, 4th, and 5th order products, but obviously worse 2nd order performance above 25hz.

Given a drive level of 20Vrms(~100 watts into a 4 ohm nominal load), it was sufficient to move both subs nearly to xmax at 20-30hz. I find performance in this region to be more indicative of non-linear performance at high excursions. With that said, I would have given the nod to the Atlas 12" as the better performer, except for the fact that the mechanical noises this driver produced in free-air made it nearly unlistenable. The upper end performance of the tc2+ was also very good, and this sub generally shows better performance at higher frequencies and lower excursions.

Final words:

All in all, I'd say both subs are clearly among the better drivers I've tested in my time for this price range. Whichever sub is the winner would depend on your specific needs.

Having had both subs in my car for a period of a few months, in the same box, with the same settings I'd say they are nearly identical in sound quality. The tc2+ had a very slightly deeper, punchier sound and the Atlas 12" was a bit lighter. Hardly even noticeable unless you owned both for awhile and were really familiar with the sound of both subs.

[mtnickel]

Great review.
I was very close to purchasing 2 atlas 12's. Currently I own a Stereo integrity magnum (TC9 motor). I'm faily content with the sound.

Maybe i skipped over it in the review, but which sub will have the most output. Longest stroke basically. I saw some excursion shots of the atlas and it didn't seem to be moving too much. perhaps it was a limited amount of power sent.
Any power recommendations for amplifcation of these 2 subs?
Thanks. Come summer time, i may just have to try one or 2 of these out. The atlas and XBL look very tempting.

Mark

[npdang]

They're actually very close in output, I'd say identical. My choice for high excursion would be the tc2+ since the Atlas does make some audible noise at high excursion. In the car, it's pretty much flip a coin though since you will never be able to hear a difference.

[DearS]

I wonder if it has anything in common with ascendants new subs.

[DearS]

were the drivers tested free air?

[pervo]

the variable qts is something i want to play w/, w/ a three position switch installed

too bad the power handling isnt up to what i wanted at the time... in retro spect i should of picked up a pair of 12's

[mk1982]

how much are they and how do they compare with an xls/xxls ?

[DearS]

atlas is not around for the time being. and The TC2+ can be found at Oaudio.com

for a review between the xxl and TC2+ check out this thread......for an opinion from an experienced person.....

http://www.htguide.com/forum/archive/index.php4/t-14613

and tata...........the shiva is include (I own a shiva)

http://www.mfk-projects.com/woofers.htm

[Bob]

Hi, i've had 2 Atlas 15's in the back of my car for about 2 months now in the standard recommended low q setting, and it never really sounded 'right'. Well today I was bored and decided to fool around with the most complex wiring option for the 2 woofers, series series 12 ohm total load, just to see what the results were. I have to say that I was pleasantly surprised by the results. The 6 ohm configuration must be leaps and bounds more efficient, because I took at least a 25% loss in total power when wiring this way and it remained the same volume as at 8 ohms for both woofers in low q mode... with absolutely no adjustment to my gains.
Also the sound really opened up, the drivers became much more musical, more pleasant to listen to, and really seemed to blend in much better with my components. I would go so far as to say a huge increase in transient response.
Do you still have the Atlas 12 in your posession Npdang?
From my results of trying the 6ohm mode it seems like it would be worthwhile to test it in this configuration, as to my ears it seems to have made a noticeable increase in transient response and efficiency paired with a loss of distortion.
And for reference to those who are bound to ask, my 2 15's are mounted infinite baffle style in my trunk, which has approximately 10 cubic feet of airspace.

[npdang]

I actually sold the sub quite a while ago. I think you're right though shorting the coil is not the most efficient configuration. Not sure on distortion.. can't see how that would affect it.

[10K2HVN]

Hi, i've had 2 Atlas 15's in the back of my car for about 2 months now in the standard recommended low q setting, and it never really sounded 'right'. Well today I was bored and decided to fool around with the most complex wiring option for the 2 woofers, series series 12 ohm total load, just to see what the results were. I have to say that I was pleasantly surprised by the results. The 6 ohm configuration must be leaps and bounds more efficient, because I took at least a 25% loss in total power when wiring this way and it remained the same volume as at 8 ohms for both woofers in low q mode... with absolutely no adjustment to my gains.
Also the sound really opened up, the drivers became much more musical, more pleasant to listen to, and really seemed to blend in much better with my components. I would go so far as to say a huge increase in transient response.
Do you still have the Atlas 12 in your posession Npdang?
From my results of trying the 6ohm mode it seems like it would be worthwhile to test it in this configuration, as to my ears it seems to have made a noticeable increase in transient response and efficiency paired with a loss of distortion.
And for reference to those who are bound to ask, my 2 15's are mounted infinite baffle style in my trunk, which has approximately 10 cubic feet of airspace.
for IB application, youre suppose to be using the "high q" setting.........

[Bob]

Yes, for a true IB, where you have at least a volume equal to the VAS of the combined drivers, you're supposed to use the high q setting... but for IB in the trunk of a car where the total air space for 2 15" drivers is ~10 cu ft, low q gives a much flatter response, with a total q of around .701 instead of the over 1 q I would get using the high q setting. Also I fooled around with low, mid, high, and even several resistors in between low and mid, and until I tried the 6 ohm configuration low q sounded the best.

[Bob]

Oh and thanks for the response Npdang, I just thought if you still had the driver on hand it would be interesting to see the actual measured effects of this configuration, since Ascendant never got around to posting any actual data on it and at this point, probably never will. It seems somewhat counter-intuitive to me that the 6 ohm configuration would have a quicker transient response, with it having more voice coil to run through, but my ears tell me that it in fact does. Maybe the magnetic braking effect used for the variable q makes the woofer sloppier than a standard configuration woofer? This could explain the poor performance in relation to inductance as well... if the published inductance is in fact correct.

[demon2091tb]

Any ideas on a Atlas 15" enclosure size and QTS with 500rms?

Thinking about replacing my Tempest with one, if i can get it to work well in 2.5-3cf.

[MIAaron]

http://www.ascendantaudio.com/archive/Atlas%2015%20sealed%20enclosure%20recommendations. htm

[cotdt]

My TC2+ doesn't look like that at all! I got a black tc2+ that looks different...

[mvw2]

Yeah, the cone's black now. I got one for Xmas. Everything else is identical with the posted pics. It's just cosmetic differences.

Saddly, have yet to run it in my car...soooooo lazy. But, I did run it full range on the floor off my little shelf stereo and as the subwoofer substitute for our entry level Sony home theater system(100W), again just sitting on the floor. It's tough to get a good perception of the driver outside of an enclosure. About all you can do is stick your head in front of the cone and guess, lol.

[nickgonzo]

lol!

[cotdt]

dammit