LMS-5400 buy-in - Page 21 - Home Theater Forum and Systems - HomeTheaterShack.com
 
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post #201 of 312 Old 09-25-07, 08:45 AM
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Re: LMS-5400 / RL-p18" buy-in

Ilkka,
Do you have the equipment to test the LMS T/S parameters? I'm interested to find out how close the factory specs are to the actual specs.
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post #202 of 312 Old 09-25-07, 09:15 AM
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Re: LMS-5400 / RL-p18" buy-in

Chris,

I do have an extra avalanche lying around actually (beside the two I'm already using in my two towers), and no, I don't have a brahma to compare it to directly but did have a Tumult 15" MK1 to compare it to months ago.

in addition to your observations, here are some corrections/additions:
1. It is not a 3" 2.8 ohm DCR copper coil of the same length and construction...it is actually a 3.4" 2.2Ω coil, and albeit similar construction, is slightly variant in length.
2. the Suspension is completely different I'm afraid. The spiders are not only softer, but have a different profile and are NOT from the same manufacturer.....that's why I asked were you got your info from, because I can assure you Chad did not use the same supplier that Dan and his team did.

they do have certain similarities obviously, but to call it a Brahma with a different dress is not very accurate IMO. Sorry.

One note is, that although Chad is no longer using them, I don't see where your comment of "I wouldn't see why anyone would pipe in as Chad is no longer using this design and has a new business and product line to promote" becomes applicable here; he is still servicing them (actually, Scott is now since he took over AA side of business)........ Not to get into a bashing contest with you, but you are the one claiming the avalanche is a brahma in disguise, I'm telling you it is not and can assure you its creator will tell you it is not, and your response is "you take his word for it"? I thought the burden of proof is on the claimer, no?

Feel free to call/email Chad or Scott directly and hear it from the horses mouth if you please.

As for the conquest Driver, it was designed from ground up. New Motor, new Suspension, new surround, new cone, coil, etc. high power, high excursion capabilities. I'll see if I can post a couple of pics with permission


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post #203 of 312 Old 09-25-07, 11:34 AM
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Re: LMS-5400 / RL-p18" buy-in

Mark, thanks for the voice of reason. I got this off on a tangent and is not in the spirit of all of the good stuff going on on this forum.

I was just trying to shed some light on some of the sources of distortion, the design compromises made (in particular designs), based on my understanding of them.

I didn't think it was a big deal discussing some of the Adire stuff because the company was no longer in business (though Dan is apparently doing well) and their products are still under discussion.

From a motor standpoint Brahma Mk I was a modified RE HC / Blueprint 03 motor with rebates cut in the top plate and core and a different length coil. This was tweaked a bit over time. Mk II was almost the same (slightly different pole extension pole vent and gap width) but used a different factory for the T-yoke and top plate. When Adire took things down to Chile (and the subsequent production in WA state) the coil diameter changed to 2.5" to provide more differentiation with the Tumult (3") motor.

ssabripo,

I think you'll find that Ascendant didn't make special tooling for a 3.4" coil and it is in fact a 3" (2.997" former ID) and the spider is what I said it was (NuWay die number 3363) and you are mistaken.

This also matches up with what was posted on the Ascendant site (though they said both 2.8 ohm and 3.2 ohm DCR over time).

http://web.archive.org/web/200502042...alanche+15.htm

Still, believe what you want unless you want to cut open your woofer and take a caliper to it.
I won't bug Scott about it and I'll drop the issue (again the point is really a bit moot due to availability).

I don't know Chad but Scott is an super nice guy and great engineer by the way. I'm glad to see those guy doing so well these days.
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post #204 of 312 Old 09-25-07, 03:05 PM
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Re: LMS-5400 / RL-p18" buy-in

Quote:
ISLAND1000 wrote: View Post
Ilkka,
Do you have the equipment to test the LMS T/S parameters? I'm interested to find out how close the factory specs are to the actual specs.
At the moment, no. In the future, probably.
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post #205 of 312 Old 09-25-07, 03:18 PM
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Re: LMS-5400 / RL-p18" buy-in

The measured specs i got off my LMS 5400 after some breakin(might still change a little) are:

Fs 18.58hz
Re 3.99ohm
Qms 7.70
Qes 0.40
Sd 1098cm2
Vas 221.3L

Vs Published

Fs 18.00hz
Re 4.00ohm
Qms 13.01
Qes 0.39
Sd 1098cm2
Vas 216.0L

So very close, all the TC sounds drivers I have measured have been about that close, enough so you can hardly see a difference in the graphs when modeling them.

Nathan
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post #206 of 312 Old 09-25-07, 08:29 PM
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Re: LMS-5400 / RL-p18" buy-in

Quote:
funky_waves wrote: View Post
The measured specs i got off my LMS 5400 after some breakin(might still change a little) are:
Nathan... does this mean that break-in is measurable and do you actually have any measurable results?

Thanks!
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post #207 of 312 Old 09-25-07, 11:25 PM
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Re: LMS-5400 / RL-p18" buy-in

While working on another, rather un-related project, some considerations came to mind that I thought should be added to this discussion and measurement of these different drivers. Ilkka did mention that these tests were mostly at less than 10mm of Xmax. Further re-iterating my point that we are comparing executions of various designs and not some theoretical ideal of each design, it should be taken under consideration that both the suspension linearity and low level/near center linearity are what Ilkka really tested in this free-air, near field example. Of these drivers, the LMS does likely have the best suspension. The shape of the distortion vs. frequency curves DO show that the motor is contributing, but there is no separation of either from this preliminary set of measurements.

Let's also remember that the frequency response of the units is NOT the same. Obviously the LMS is behaving very well, but between the other 3, the differences aren't very significant if you also consider at the frequency response differences. I would suggest reserving some judgement until we see some higher excursion and power, in-box conditions. The different shapes of the BL/Le/compliance and other factors will manifest themselves differently, and even somewhat differently in different box designs/alignments. As the old saying goes, it really is how you use it...

Mark Seaton
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post #208 of 312 Old 09-25-07, 11:32 PM
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Re: LMS-5400 / RL-p18" buy-in

Lot of action in this thread. Bottomline, we have insufficient data now and a lot is left to speculation. It would make sense to wait until this driver is in a box so we know what happens when the rubber meets the road. I see a lot of tangential conversations and far fetched speculations. We will have a lot more to talk about once the real subwoofer is built and measured.
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post #209 of 312 Old 09-26-07, 03:35 PM
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Re: LMS-5400 / RL-p18" buy-in

Quote:
Sonnie wrote: View Post
Nathan... does this mean that break-in is measurable and do you actually have any measurable results?

Thanks!
I dont have before and after for the LMS but the suspention does loosen up. I have before and after of a qvc Tc3000,
before:
Fs 22.22hz
Re 1.17
Qms 5.98
Qes 0.39
Sd 823cm2
Vas 117.78L

After:
Fs 20.65
Re 1.17
Qms 6.33
Qes 0.39
Sd 823
Vas 134.30L

Fs goes down Vas goes up, due to Cms going up when the suspention loosens up. Not a huge difference.
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post #210 of 312 Old 09-27-07, 01:12 AM
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Re: LMS-5400 / RL-p18" buy-in

Thanks Nathan... no, it's not huge, but it is measurable none the less. Very interesting. That might be something you could post in the Driver break in thread.
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