LMS-5400 buy-in - Page 24 - Home Theater Forum and Systems - HomeTheaterShack.com

 
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post #231 of 312 Old 10-05-07, 06:42 PM
Klip
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Re: LMS-5400 / RL-p18" buy-in

Quote:
ISLAND1000 wrote: View Post
Ilkka,
... Will you perform tests in the parking lot? How long before some more test results?
Easy does it, or Ilkka will end up - Ilkkarus - you know, from the 21st Century Finnish mythology...

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Ilkka wrote: View Post
P.S. With 4 Crown CE4000 - it's enough poweh to clip anybodies wings!

Last edited by Klip; 10-05-07 at 06:56 PM.
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post #232 of 312 Old 10-05-07, 09:10 PM
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Jai
 
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Re: LMS-5400 / RL-p18" buy-in

Quote:
Ilkka wrote: View Post
2nd order BW at 16 Hz.


Yes I did but I will use the stock fans during the measurements just in case.
2nd order BW at 16Hz is too low and others will disagree with all their energy. My experience with this design is that it should go no lower than 20Hz. 4th order L-R, at 16Hz should be ok, not a second order. If you do decide to go with 16Hz 2nd order, approach limits with great caution. Your tests are very controlled, so you will find the limitations of your sub easily and my fear of your sub bottoming out maybe unfound. You don't want bottoming out in any case. Period. You know everything about my subs and you know what happened with lower settings. Approach 16Hz with caution. The last thing I want to see is a post here mentioning your sub bottomed out. Considering how long it would take for another driver to reach you (do you have 2 of these drivers?) I would be very sad if your driver bottomed out.
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post #233 of 312 Old 10-05-07, 09:13 PM
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Jai
 
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Re: LMS-5400 / RL-p18" buy-in

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Ilkka wrote: View Post
I don't think going lower than 15-16 Hz is a good idea. That means one has to use more than 2000 grams of additional weight per each PR...
2000 grams is fine and they were designed to take up to 2500gms. Those PRs have very robust components. I would still keep it below 2000. So 16Hz is the sweet spot.
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post #234 of 312 Old 10-05-07, 09:18 PM
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Jai
 
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Re: LMS-5400 / RL-p18" buy-in

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Klip wrote: View Post
Easy does it, or Ilkka will end up - Ilkkarus - you know, from the 21st Century Finnish mythology...



P.S. With 4 Crown CE4000 - it's enough poweh to clip anybodies wings!
One more thing about these amps. The first time, I did not follow the instructions carefully. When you bridge them, the gain on one of the knobs should be zero. I don't know what difference it makes, but the instruction manual has a clear note on this. So pay attention to that. Better to follow what it says. Secondly, try playing with the sensitivity settings to see what a good sweet spot would be.
Man Ilkka, I simply cannot wait to see the results. You are getting me very anxious, happy and nervous and the best word to describe this is anticipation. So please make it happen soon
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post #235 of 312 Old 10-05-07, 10:59 PM
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Will
 
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Re: LMS-5400 / RL-p18" buy-in

Quote:
jmcomp124 wrote: View Post
2nd order BW at 16Hz is too low and others will disagree with all their energy. My experience with this design is that it should go no lower than 20Hz. 4th order L-R, at 16Hz should be ok, not a second order. If you do decide to go with 16Hz 2nd order, approach limits with great caution. Your tests are very controlled, so you will find the limitations of your sub easily and my fear of your sub bottoming out maybe unfound. You don't want bottoming out in any case. Period. You know everything about my subs and you know what happened with lower settings. Approach 16Hz with caution. The last thing I want to see is a post here mentioning your sub bottomed out. Considering how long it would take for another driver to reach you (do you have 2 of these drivers?) I would be very sad if your driver bottomed out.
Jai - 2nd order BW @ 16Hz isn't too low. Even when you had your Rane set at 15Hz (with your 5400s tuned to 15Hz) you admitted you were a-ok.
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post #236 of 312 Old 10-06-07, 12:08 AM
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Jai
 
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Re: LMS-5400 / RL-p18" buy-in

Quote:
WillyD wrote: View Post
Jai - 2nd order BW @ 16Hz isn't too low. Even when you had your Rane set at 15Hz (with your 5400s tuned to 15Hz) you admitted you were a-ok.
Willy,
I don't recall that. If so, maybe I didn't update on forums. But as my memory recalls, anything below 20Hz 2nd order was unsafe. Can you point me where I said that so I can go and update.
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post #237 of 312 Old 10-06-07, 12:11 AM
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Re: LMS-5400 / RL-p18" buy-in

Quote:
jmcomp124 wrote: View Post
Willy,
I don't recall that. If so, maybe I didn't update on forums. But as my memory recalls, anything below 20Hz 2nd order was unsafe. Can you point me where I said that so I can go and update.
http://www.avsforum.com/avs-vb/showp...&postcount=216

I don't recall you ever having a problem with the SSF set to 15Hz. I just thought you were afraid of potential problems at that setting so you set it higher.
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post #238 of 312 Old 10-06-07, 11:11 AM
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Jai
 
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Re: LMS-5400 / RL-p18" buy-in

Quote:
WillyD wrote: View Post
http://www.avsforum.com/avs-vb/showp...&postcount=216

I don't recall you ever having a problem with the SSF set to 15Hz. I just thought you were afraid of potential problems at that setting so you set it higher.
Thanks for the link Willy. I haven't been frequenting those forums as much as I used to, and I am back here only to see Ilkka's mesurements. You are right, I didn't post about problems with a setting lower than 20Hz. Sometime during the long experimentation process, I managed to bottom out one of the subs again when I pushed to +6dB beyond reference. If it is just reference levels it was fine. WIth the amount of power that the CE4000s deliver, I could keep pushing and the sub gave up before the amp.
At one time while measuring the THX intro scene, it was about +6dB beyond reference and there was a mild bottom out and thankfully that did not damage anything. So I switched back to 20Hz and since, I have not experienced any bottoming out. My fear of the potential problem was true though. Post #310 in my thread on avs talks about this 20Hz setting when I registered 119dB at LP. But the fact is, it did bottom out when the HP filter was set to 16Hz for the THX exploding ball scene. I hope this clears up some confusion. I had revisited WinISD models at that time and 16Hz 2nd order BW did show some warning signs with the peak excursion of the main driver. Blame it on the crown , it doesn't stop delivering .
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post #239 of 312 Old 10-06-07, 04:49 PM
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Re: LMS-5400 / RL-p18" buy-in

What's with all this concern over bottoming the LMS 18 below 20hz.....especially in such a small enclosure? As LLT owners have been showing for some time now - most with only 15" drivers - you'd really have to be asking for trouble to get one to bottom. Keep a lowish tuning and make the enclosure smaller like Ilkka is doing, and you get even more protection. You loose low end sensitivity, but you can't have it all if staying so small. If the LMS is bottoming with a 16hz tune and 16hz highpass, then I'd look to the claimed xmax capabilities.

Ilkka, what will the final enclosure volume be? 16hz tuning with a 16hz highpass seems like a bit of a waste of potential with these drivers to me. I highly doubt you will be listening at 130db+ levels, so trade some headroom for extension.


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post #240 of 312 Old 10-06-07, 05:22 PM
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Will
 
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Re: LMS-5400 / RL-p18" buy-in

Quote:
Sometime during the long experimentation process, I managed to bottom out one of the subs again when I pushed to +6dB beyond reference. If it is just reference levels it was fine. WIth the amount of power than the CE4000s deliver, I could keep pushing and the sub gave up before the amp.
Lets be real though, you're talking about purposefully playing them +6dB hot and cranking them up. That isn't a real world scenario.

Quote:
If the LMS is bottoming with a 16hz tune and 16hz highpass, then I'd look to the claimed xmax capabilities.
Well there were some other things going with Jai's setup early on. We'll know the full story with Ilkka's setup...but you are probably underestimating these CE4000s, to be honest. They really are beasts. And you got it mixed up, one shouldn't question the claimed xmax spec. Remember Steve, its the xmech that determines the mechanical limit. And that would be the only problem with the 5400, it doesn't have as much throw past xmax as a lot of other drivers have.
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