Treo Engineering Subwoofers

AustinKP

Originally posted by neomagus00
why is it that the brahma uses OTS parts, while the w7 is totally custom? when i think of OTS, my perception of quality goes down (think stock vs. custom in cars)... does this apply here?

I wondered the same thing. However, anyone you ask can vouch for the superior quality of the Brahma. My question is, if Brahma uses off-the-shelf parts, why is it so much better than the competition? What sets them apart from other companies using the same parts?

geolemon

Well, by off the shelf parts, I mean standard, mass produced parts.
They don't have a performance disadvantage, they are just mass produced, giving them a per-unit-cost advantage.

Take the basket, for example...
The W7 uses a custom basket. It's deep as the grand canyon. It's quite a piece. But to tool up to build a custom basket, you are talking about around $10,000 in machining and mold-making costs alone - per basket size - before you've even spent a penny on actually pouring and buying the actual cast basket units.
Not to mention, JL has spent a fortune on patents for various parts - including the basket, I believe.

But for what performance advantage? (that's the question )

Xmax on the Brahma 12 (28mm) is nearly the same as the W7 12 (29mm).

The basket that is used for the Brahma allows for excursions up to about 34mm, and that exceeds it's 28mm Xmax by quite a bit.

Yes, the W7 has an even deeper basket... but you are also trading off mounting depth in the process. One of those "What do you mean by performance?" things. You gain in Xsus - but only well outside the driver's operational linear range.
Also, you are trading off a heck of a lot of mounting depth (and money, let's not forget money! ) for it.

The suspension, likewise. The W7 has one of the most wonderful suspensions I've ever seen. However, it doesn't offer a big performance advantage, because you won't see any additional excursion until you are well outside the driver's operational linear range.
The suspension on the Brahma is fairly standard.. but well engineered at the same time. The spider was custom designed (that's not very expensive to do), and yields a flat Kms curve across it's linear range. Half roll surround is appropriate for it's range of travel... cone is rigid enough, has the proper mass...
If you compare the Brahma to the W7 inside their linear range, you might even determine the Brahma's suspension curves are better at any rate.

It just comes down to... if you have standard parts available that offer you all the performance that you are looking for, to reach your design goals, why would you spend tens of thousands of dollars tooling up to make your own [unproven] parts?

geolemon

Originally posted by AustinKP
My question is, if Brahma uses off-the-shelf parts, why is it so much better than the competition?

It's a matter of proper selection of parts.
In the case of the Brahma, these parts were chosen, because in combination, they allowed the designers to reach their design goals.

The cone/former had the proper stiffness and moving mass, allowing for high-excursion low-distortion performance, and the Fs that was targeted.
The suspension componentry yields a flat Kms curve across the whole linear range of motion, and the spider was also designed to provide the desired amount of stiffness to satisfy the Fs that was desired, and the target small-enclosure size desired.
The basket dimensions allow for the desired excursion and spider dimensions.

But those things are effects, not causes...
There's a major reason why it is better:

What sets them apart from other companies using the same parts?

XBL^2. It is very very different from traditional motor architectures... and yet such a small difference, at the same time.
XBL^2 is what allows a short (29mm) voice coil to reach 28mm of excursion linearly - meaning the BL is flat within that range.

The greatest source of distortion is intermodulation distortion...
This is inherent in most loudspeakers, as most loudspeakers have parabolic-shaped BL curves. That is, motor strength is highest in the "at rest" (cone centered) position, and as the cone travels away from that at rest position, motor strength gradually falls off. As you observe the cone in motion, as it moves in and out, it's motor strength is changing... increasing every time it approaches the center of it's motion, and decreasing as it moves away. This imparts a distortion on the waveform.
The Brahma, by virtue of it's XBL^2 motor, doesn't suffer from this... it's a dual-gap technology, so that as the voice coil moves, the coil count in the magnetic field stays much more constant than with a traditional, single-gap subwoofer.

XBL^2 is nice because of it's simplicity...
At the risk of oversimplifying all the details of coordinating the length of the voice coil to the dual-gap geometry... essentially, it's a matter of taking a thick top plate, and cutting a groove around the inside of it. That's the additional "custom" expense per woofer. :cool:

Look at JBL's GTi...
The DDD technology is wonderful also.
But, it also requires a massive amount of fabrication... custom basket, magnets, coils, former... everything. It's got as many custom parts as the W7, and I'd bet assembly is more expensive.
And what did they really end up with at the end of the day?
XBL^2.
DDD is also a dual-gap technology, just implemented a bit differently... and a lot more expensively.

So...
...if you want the performance of a Brahma - but you want the bigger price tag and all the custom parts to go along with it... you have that option. The JBL GTi.
(but the Brahma still outperforms it, also )

neomagus00

okay, that makes sense - same or better performance, cheaper parts. good .

to summarize:
-w7's customization only takes effect outside linear operation of the driver, and is thus essentially worthless in this context
-yay for XBL^2

okay, it's settled... as soon as i can afford it, there's gonna be a brahma 10 (or 12 if i can find a way to fit it!) in my trunk

geolemon

Well, the W7 is a fantastic design.
It's got a bottomless suspension.
It's just that it's linear excursion is a mere 1mm more than the Brahma.

And if that mm is important to you, you could also consider Resonant Engineering's **** model - which still has the same ~34mm physical excursion limit (of the basket), but has a linear performance right out to 32mm, which beats the JL's linear excursion by several mm... thanks to a larger XBL^2 motor.

I've always thought it would be fun to put an **** motor on a W7 chassis... but I passed up my opportunity to purchase a blown 13W7.

Of course, Adire does special-order the expensive Parthenon... a massive XBL^2 neodymium-ring motor, which has a linear excursion of over 4.5" - one way.
That's over 114mm of linear excursion. Over 9" of peak-to-peak cone travel.
They build it to demonstrate that XBL^2 is scalable - and interestingly enough - nearly infinately. :eek: Traditional motor architecture is not scalable that way... the W7 really pushes the boundaries for single-gap.
And yes, it's very expensive if you want one. They tool them in onesies and twosies as ordered, after a personal consulting and parts selection session. :cool:

neomagus00

how expensive is very?

geolemon

I believe the Parthenon starts around $4,000, less if you have an Adire connection.. but still very pricey.

neomagus00

somehow i don't think "very pricey" quite covers that!

what's a neodymium(sp) ring motor? neod and motor parts i get, what's the 'ring' bit?

Systems

Originally posted by Jstas
This isn't going to turn into another ED thing, is it?

for your sake, no

AustinKP

Uh, where did that come from? Before you reply to a question concerning the future posts, try reading the rest of the 30 posts that follow...

exalted512

Originally posted by AustinKP
Uh, where did that come from? Before you reply to a question concerning the future posts, try reading the rest of the 30 posts that follow...

dont sweat it, its probably some rejects from CAF trying to start **** again...maybe if we ignore them they will go away
-Cody

geolemon

Hey now...
I'm a reject from CAF.

exalted512

lol...not you...theres a few CAF members that are very helpful, then theres some others that are total dicks and the complete lack of moderators is the main reason i keep my posts on there to a minimum
-Cody

geolemon

A ring magnet just is a round neodymium magnet with a hole in the center... a ring shape.

The Parthenon was so named because of it's unique pillared construction, with a neodymium ring magnet at the top of each pillar.

I've got some pictures of the working Parthenon unit that Adire brought to CES, I visited their booth a couple times during the week:
CarAudioForum CES gallery for geolemon

Parthenon pics start at CES00037.jpg and go to CES00043.jpg.
In the one pic, I pushed the cone out quite far with my fingers, to show how the Arachnid spider/tinsel unit works.

It's a unique thing... replaces the spider completely with that copper spring unit, the copper springs also acting as the voice coil tinsel leads.
No more tinsel lead slap, and no more spider-limited Xsus. :cool:

neomagus00

freaky-looking thing, very strange... cool, but strange