Pssst, want a sneek peek at a brand new driver?

[CJ Paul]

Very nice work. I like the looks of the driver (literally and in a prospective sense).

[ThomasW]

Ascendant Audio is open for business ...... :T

[cjd]

I'll have to swing by when I get a chance, check out the setup! If I'm still working at that point, probably pick up some drivers I don't really need. Er... who said I don't need 'em? Lookin good. Those 18's are interesting! The dust cap looks so teeny.

C

[Jerry Pease]

who ordered already? Which one is the bad boy to get?

[cjd]

Jerry: For your room, the 15" Avalanche (or the 18's if they fit :twisted: ) are the way to go. The Avalanche 15 models out slightly better than a Tumult in the same size box on slightly less power.

The Avalanche 15 doesn't roll off as fast on either end. Power difference for the 118dB output level I matched at (where excursion limits are reached) was 1200 for the Tumult, 1000 for the Avalanche 15. At the price difference, it's a no-brainer IMHO. Plus that carbon fiber dust cap!

FWIW, a 65L box is what's recommended, where it definitely has an edge on the Tumult. Yet another reason this would be the driver for your HT.

The 18 wants a big box. 250L sealed. Looking like it might really enjoy an IB alignment.

I should comment, that Atlas 15 models superbly in an infinite baffle! Man, I have to get me a pair of those to replace the Dayton 15" IB drivers I have (which I'm sure will suddenly seem like sad little things when I'm done).

C

[Brian Tatnall]

I was able to play with the Atlas 12" and 15" along with the Avalanche 15. The badboy to get? Avalanche 15" in 2.2 sealed with 700 kicks pretty hard considering the power.

[Kurtj]

I was thinking about a sealed Tempest (Q=.707, 122l) but now I think the Atlas 15 is the way to go for me. XBL for only $35 more than Tempest!
I haven't been able to model consistently this driver. Can any one help with Q=.707 sealed?
What size box will I need?
How does it compare to the Tempest?

[Jerry Pease]

anyone bought? where are the reviews?

[Kurtj]

Bought yesterday. FedEx will deliver Thurday. The 250A from Acoustic Visions should be here by Monday. In about a month , I'll be able to answer questions.

[Brian Tatnall]

anyone bought? where are the reviews?

Hopefully, less than a week away.

[JonMarsh]

Well, I've got tracking numbers - expected delivery date is 1/04/05.

Chad's brewing up something special to test- may be really nice for us dipole guys, but it's not a "done deal", so I have to stay mum for now. But I like the way he thinks... :B


~Jon

[cjd]

Geeze... You'll probly have 'em before I could even zip over to pick some up!

The 12" Atlas I heard sounded very good (sealed, looked to be ~2.5cu/ft?). It was demo'd with a pair of MTMs using the Behringer digital XO, and with about two seconds of setup time (just to verify levels) it was not really possible to isolate the crossover frequency at all. With the sub in a corner, driver facing the wall. It was clean, and it ran quite deep. I was impressed - not quite what I get out of my IB but very close.

C

[Paul H]

I was looking at these and thinking what great dipoles they'd make, when I found this at the bottom of the web page :cry:

At this time, we can not accept international orders.

I emailed them requesting info re shipping to Canada now or in the future. I'm sure there's a few interested people on the cold side of the border.

Paul

[Chad Kuypers]

Paul,

I sent you a reply to your email. We DO in fact ship to Canada. Sorry about that. I will change the website to more clearly state both U.S. AND Canadian sales.


Chad Kuypers
Ascendant Audio

[Paul H]

Thanks Chad.

Paul

[Paul H]

Any opinions here on how high could the 15" Atlas be crossed over, and at what filter slope? I'm thinking of a use for in the lower end of a dipole - down to 50-60 Hz.

Paul

[JonMarsh]

The relatively low cone mass and low Le suggest a realtively high upper usable frequency, but without testing and some distortion curves (above 100 Hz dependent more on cone than motor behavior) it's hard to say- should be promising.

I have some Atlas 12's on the way, and hope to do some measurement before going to Denver mid month.

Therein lies a tale, as my "minor re-vamp" to the CLIO testing PC turned into a major headache, 8O finding a faulty power supply in the new chassis, (replaced with an Antec 400W unit I had leftover from upgrading my desktop system), then having video card problems with the original card (out goes the Radeon, in goes a new NVIDIA 5500), and now installing the 6.15 CLIO update (which of course, once I erased the old Windows version, took me 20 minutes to find.

Some days just aren't my days. Was going to do some work out on the patio, and again it's raining solid all day long- just like most of the last week! :roll:

Well, progress is being made, but sometimes it feels like two steps backward, one step forward!

[Jerry Pease]

is the avalanche 15 shipping?

[Chad Kuypers]

Any opinions here on how high could the 15" Atlas be crossed over, and at what filter slope? I'm thinking of a use for in the lower end of a dipole - down to 50-60 Hz

I will be doing some measurements this week to help determine the high frequency effectiveness of the Atlas subwoofers. From some inital measurements they in fact go surprisingly high in frequency with no anomolies in the impedance curve. I will be building a large flat baffle jig for testing them. I will also be running the same test on the Avalanche subwoofers which appear to perform better in this respect than I originally anticipated.

is the avalanche 15 shipping?

Yes. There was an small initial run of Avalanche 15's and 18's that immediately sold out last week. However, as of this coming Tuesday EVERYTHING will be built, finished, packed, and ready to ship.

[Evil Twin]

Slowly the pieces necessary to my plan are coming together.

Unquestionably the BL force is strong in these resplendent new Atlas 12" woofers delivered to the Imperial lab today. Still, their mettle remains to be tested, before they can take their place in our new project.

However, my intuition says that in all probability my master will be well served by these new drivers. Only time will tell for sure.

[iron_monkey]

Chad, if you can cater for US customers, why cant you cater for the World market? Are there extra hassles involved compared to catering for US customers?

[cjd]

Chad, if you can cater for US customers, why cant you cater for the World market? Are there extra hassles involved compared to catering for US customers?

Shipping is lots of fun, as is receiving funds. Just a guess on my part from back when I looked into some business related stuff.

C

[tktran]

O-Audio and SoundSplinter have no problem shipping their 12" and 15" TC- Sounds based subwoofer drivers...

[ThomasW]

Reality check time .......

AscendantAudio has been in operation for 3 weeks. I'm sure that in do time, Chad will offer products shipped anywhere the customer desires.

Cheers
Thomas

[Chad Kuypers]

iron_monkey,

We are working on international orders and shipping as we speak. We want to get everything set up properly so there will be no hassles or delays involved if and when somebody orders from overseas. It shouldn't be very long at all before we can take international orders. Thanks for being patient and sorry for the wait.


Chad Kuypers
Ascendant Audio

[Jack Gilvey]

Too much to resist. I've got a pair of Atlas 15's on the way to use in IB with a large closet (which has served this purpose before) adjoining my room receiving the backwave. I'll be cutting it close at 5 x Vas for the pair. I'll run their 2-ohm coils in series and go for a Qts of ~.7. I've got an old PE #300-800 150w plate amp with no boost/rumble filter that should do nicely. The Avalanche 18 is mas macho, but the Atlas drivers are just too appealing in their ability to provide almost any Qts at useable impedance. Here's what Unibox predicts:

Image not available

With such (presumably XBL-clean) output available with so little power applied, I think I'm in for a treat. Chad, as you might expect, was a pleasure to deal with and has been over-the-top helpful. Given the last few posts, I was worried that he might not ship to New Jersey, but my fears happily proved unfounded.

[Jack Gilvey]

And, with Chad's permission, here are some pics of the upcoming Avalanche 12:

https://web.archive.org/web/20050117005637/http://ascendantaudio.com/Avalanche%2012%20prototype%20pictures.htm

Image not available

No specs yet. Beautiful, no?

[JonMarsh]

One of these is on the way to Northern CA so I can include it in my testing series with the Atlas 12 and others- I just finished building a dedicated test stand for testing the higher power 12" sub drivers.

Needless to say, I'm looking forward to seeing this "little baby".

Image not available

[hardg]

Hi, I'm having trouble deciding on which of the ascendant drivers I should pick up for my HT, and there doesn't seem to be any enclosure calculators out there that work with a mac, so I'm looking for some help.

This will be going in 16x13 room that is open to the kitchen, and also open to the hallway of my house. I have paradigm monitor 3's for fronts and surrounds, and a CC370 center. The sub will be powered with a parts express 500 watt plate amp.

So anyway, I'm torn between a 6.5 cube ported Atlas 15", and either a 2.2 cube sealed Avalanche 15 or a 4.6 cube sealed Avalanche 18. Personally, I like the idea of the smaller sealed enclosures, but which of these would be better suited for home theatre use? What kind of output do you think I could expect in-room, and is it really worth spedning what is almost double the money to get one of the Avalanche drivers? Thanks a lot, guys.

[hardg]

BTW, if it makes any difference to the above, I really liked the paradigm PW-2200 that I had a chance to audition. How would one of those subs compare to it?

[JonMarsh]

Well, you know you've hit on the major issues involved in your choices there. If you're monetarily limited, but have the space, the Atlas 15is a very cost effective performer in the larger ported enclosure.

Often, though, a smaller enclosure is preferred for esthetic reasons, and the long throw low distortion performance of the Avalanche 15 or 18 is very respectable.

For the 18, with 1200 watts, you could reach the Xmax limit in a 140 liter enclsoure, at 110 dB out at 20 Hz. The sealed box will have excellent transient response, better than a ported system or PR type, but it does require more power, and won't reach as high a playback levels.

But even the Avalanche 15 would be able to muster about 107 dB at 1 meter at 20 Hz, in about the same size enclosure. Plug the T/S parameters into Unibox and you can play with it yourself; remember, the smaller enclosures will need more EQ and more power.

Where the Atlas makes sense is if you can't afford the amplifier power, the driver budget is more limited, and you can deal with the enclosure size. Then you can get about the same output level with a shorter throw driver due to the port action, which minimizes the driver excursion at box tuning and allows higher output levels. But it will be a large enclosure, with a 6" port; something like the Aerial Stryke 15" design ThomasW built.

[Evil Twin]

And, with Chad's permission, here are some pics of the upcoming Avalanche 12:

https://web.archive.org/web/20050117005637/http://ascendantaudio.com/Avalanche%2012%20prototype%20pictures.htm

Image not available

No specs yet. Beautiful, no?

Ah, the BL force is clearly strong in this one...

[Brian Tatnall]

My review is done. It can be found by clicking the link below.

https://web.archive.org/web/20050205104455/http://www.visionaryaudio.com/Reviews.htm

[JonMarsh]

Very interesting, Brian. Losing that data must be very annoying and frustrating...

Thanks for the detailed write up and explanation of what you're looking for. Upper bass performance is something I think a lot of folks often neglect- and many drivers do, too.

~Jon

[JimRHIT]

Great review Brain Very well written and informative. Thanks for doing this for everyone.

Jim

[TEK]

How can you tell the upper bass peformance of a driver? And how high it will actually cope before starting to break up?
Is it something you can read out from the parameters?

I belive I have read that the LFE channel is expected/specified for "deep bass" frequences all the way up to 120Hz. I might be wrong...

[JonMarsh]

Hello Eric,

Well, you can get some hints from the Le, the voice coil inductance, and the measured frequency response. A difficulty with many subwoofer drivers is that there are no measures taken to deal with Le, and so the Le actually causes a roll off in response, like a crossover inductor. I've seen this in drivers like the Styke HE-15, and the Blueprint BPD series. The only thing that you can do to help is EQ the driver flat within the upper bass range (to 150 or 175 Hz).

LFE crossover point can vary depending on system setp. The important point to consider is that for the response and blending through the crossover region, the resonse must extend smoothly at least half an octave further.

The other aspect is that higher inductance also means poorer control and damping of the cone, and this shows up in woofers for which the THD rises at frequencies around 100 Hz and above. This is not as uncommon as you might think- for example, the DPL12 from Adire has very good distortion performance from 50 Hz on down, but it not as good above 80 Hz compared with some other 12" long throw woofers.

How high a driver goes up can also depend on cone break up modes, but it's rare for that to be the primary limiting factor- this is usually at 400 Hz or more, well beyond where one should be using a subwoofer driver.

~Jon

[JonMarsh]

I've just had questions coming out of the woodwork this last week on all sorts of topics regarding the 15" Avalanche and 18"- plus, a few regarding how the Atlas models fit into the grand scheme of things. I'm going to be doing quite a bit of testing in the next couple of weeks, but I've also been doing a lot of parameter evaluation and simulation, partly to fill in some of the sections that have placeholders but no recommendations yet on the Ascendant Audio site.

My hint for tonight is optimizing the Atlas 12 series, especially if you want wide bandwidth in your sub, but are driver and amplifier poor, yet have space for a moderate size box.

The Atlas 12 comes closer than any driver I've seen to being able to be all things to all men and women, with it's Qts variability. I especially like the performance possible in the medium Qts range, say, using a 1.5 ohm resistor on the adjustment voice coil.

Let's see what we can do with a moderate size enclosure - the main things to watch out for are controlling the Q and the shape of the roll off in the bottom end, having enough port area, and staying withing the thermal limits and Xmax limits of the driver. For this design, I think a 300 watt amplifier will be about right- something readily available or quite close in a moderate cost plate amp, for example. Or one channel of an average 200W/ch @ 8 ohm amp- could power two with a stereo amplifier.

I chose the enclosure size to develop a box tuning that would be about 6 dB down at the Fb from the 100 Hz region- with normal/typical room gain, it should be subjectively flat in the low end, but not boomy. The Fb was chosen at 18 Hz, as this covers most of the range for HT sound effects, while still keeping cone excursion under control in the lower mid bass- say, the 40-50 Hz region, at 300 W.



Note that this provides anechoic output of 106 dB down to 20 Hz, only dropping to 104 dB at 16 Hz, before room gain. A pair would kick this up substantially, especially after considering room gain.

For the frugal HT builder, this should be an attractive way to get low distortion and lots of output for a relatively small expenditure. The only real tradeoff is needing some 120 liter enclosures, about 4 cu. ft, per driver. Dual 3" ports are preferred, though you might be able to squeeze by with single 4" flared ports.

A tube sub enclsoure would proabably be the ideal way to build this with minimal work, though a long narrow rectangular enclosure like an Aerial Acoustics SW12 would work as well; in that case, the 4" port might be most practical.

~Jon

[Dennis H]

Resistive damping

For all you EEs out there (Jon), I'm confused as usual and I have a question about resistive damping. The way I understand it, cone movement causes current to flow in the shorted coil, so that coil acts as a brake to resist movement. However, on Chad's page, he says the coil-shorted config is the most sensitive/efficient. That doesn't make sense to me as the coil-open config should apply the least braking, not the coil shorted config. Help!

[sbolin]

I chose the enclosure size to develop a box tuning that would be about 6 dB down at the Fb from the 100 Hz region- with normal/typical room gain, it should be subjectively flat in the low end, but not boomy. The Fb was chosen at 18 Hz, as this covers most of the range for HT sound effects, while still keeping cone excursion under control in the lower mid bass- say, the 40-50 Hz region, at 300 W.

Note that this provides anechoic output of 106 dB down to 20 Hz, only dropping to 104 dB at 16 Hz, before room gain. A pair would kick this up substantially, especially after considering room gain.

For the frugal HT builder, this should be an attractive way to get low distortion and lots of output for a relatively small expenditure. The only real tradeoff is needing some 120 liter enclosures, about 4 cu. ft, per driver. Dual 3" ports are preferred, though you might be able to squeeze by with single 4" flared ports.

A tube sub enclsoure would proabably be the ideal way to build this with minimal work, though a long narrow rectangular enclosure like an Aerial Acoustics SW12 would work as well; in that case, the 4" port might be most practical.

~Jon

Is that port length really about 110cm long? Yikes! 8O

[JonMarsh]

For a four inch port, yes... that's why a sonotube would be the most practical enclsoure choice. This is a lot like an Adire EBS alignement. This is tuned to 18 Hz- if you want to give up some below 20 Hz output, the tuning can be raised, say, to 20 or 21 Hz, and the port becomes much shorter.

One could also compromise a bit on maximum output level with a single three inch port; but then there would probably be some port compression or chuffing at the highest output levels.

[Dennis H]

Bump. Jon, your thoughts on the resistive damping question above?

[JonMarsh]

OK, Dennis - here's the nickel explanation (I'm just getting ready to run my daughter out to Denver International- don't have much time

- I can give you the gory details in MathCAD post this weekend..

Think of it this way- the second voice coil is an electrodynamic brake- it's not the resistor that's doing the damping, it's the current through the VC windings, which opposes the motion of the cone when not driven. Now, if you put a resistor in series with the VC, that decreases the current, and the back EMF generated damping force decrease. Going open circuit removes it completely.

I can post the not very gory math this weekend, if you're curious, as to how it relates to T/S parameters.

~Jon

[Dennis H]

Thanks Jon, I don't need the gory math -- simple explanations for simple minds.

Your explanation agrees 100% with my understanding of how it works. The open voice coil version should be more efficient -- no current flow means no braking. However, Chad's webpage seems to disagree and that's why I asked the question. Maybe someone who knows Chad could ask him about it. Grabbing some quotes from his page:

"These are the T/S specs for the Atlas 12 in its low Qts setting. .... It has the highest overall sensitivity ....."

Coil shorted
Qms 4.9
Qes .354
Qts .33
Spl 1W/1M 88.5 dB
Spl 2.83V/1M 92.6 dB

1.5 ohm resistor
Qms 4.9
Qes .465
Qts .415
Spl 1W/1M 87.2 dB
Spl 2.83V/1M 91.4 dB

Coil open
Qms 4.9
Qes .581
Qts .52
Spl 1W/1M 86.3 dB
Spl 2.83V/1M 90.5 dB

Edit: Another strange thing, Chad shows Qms being constant and Qes changing. In Dan Wiggins RDO whitepaper, he says Qes is constant and Qms changes.

http://www.adireaudio.com/Files/TechPapers/RDOOperation.pdf

[Scott Simonian]

Maybe it is a typo in the Adire RDO whitepaper. Under these circumstances the mechanical Q should not change. Just the electrical Q. But I may be mistaken.