Dual RL-P18 LLT for my 2000 cu ft HT soon - Page 2 - Home Theater Forum and Systems - HomeTheaterShack.com

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post #11 of 183 Old 04-23-07, 05:20 PM Thread Starter
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Re: Dual RL-P18 LLT for my 2000 cu ft HT soon

Quote:
Sonnie wrote: View Post
Sounds like a pretty serious project.
Well would like to be able to hit 125 db or more uncompressed in my room if I wanted to.

Do you guess what will be my next thread? "Want to soundproof my HT, as the neighbours called the police yesterday"

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post #12 of 183 Old 04-23-07, 05:29 PM
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Re: Dual RL-P18 LLT for my 2000 cu ft HT soon

It's hard to sound proof the ultra low stuff, but it can be made to sound like distance thunder with thick walls. 125db should be no problem in that small of a room.
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post #13 of 183 Old 04-23-07, 05:51 PM Thread Starter
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Re: Dual RL-P18 LLT for my 2000 cu ft HT soon

The only solution would be a cubicle inside my room I think.... But that's out of topic for the moment.

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post #14 of 183 Old 04-23-07, 06:57 PM
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Re: Dual RL-P18 LLT for my 2000 cu ft HT soon

When I play with your figures in WinISD I find the RL-P18 D2 model with the 2 ohm coils in series for 4 ohms total and 750 watts per channel from the EP2500 seems to give the most reasonable results (with my limited knowledge).

Much more power than that and the excursion and velocity seem to get a bit too large.

If I use a 550 liter box (19.423 cu.ft) with a 16Hz tune and a 21.27" single flanged 8" port combined with 4 ohms driven from a EP2500 (750watts) I get the following results. Having two boxes would be 6dB more SPL output I suppose.

SPL
Dual RL-P18 LLT for my 2000 cu ft HT soon-blaser-rl-p18-d2-series-spl.jpg


EXCURSION
Goes a bit over Xmax at full power. Don't think that's greater than Xmech though.
Includes a 1st order 10Hz electronics rolloff filter.
Dual RL-P18 LLT for my 2000 cu ft HT soon-blaser-rl-p18-d2-series-excursion.jpg

AIR VELOCITY
Exceeds the 17 m/sec 5% rule, but is only 7.5% max at full power.
Dual RL-P18 LLT for my 2000 cu ft HT soon-blaser-rl-p18-d2-series-air-velocity.jpg


I played with the box a bit with a front vent.
Seems like a big box. I'm not too use to using BoxNotes, so it was an experiment for learning.
Don't know if it's realistic. Seems correct.
The only box resonance that seems a concern is a quarter wave one at 86Hz. I wonder how important these resonances are. Takes a lot of playing around to minimize them and still get a sane box.
Anyone else use this program?
Dual RL-P18 LLT for my 2000 cu ft HT soon-blaser-rl-p18-d2-series-box.png

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post #15 of 183 Old 04-25-07, 10:57 AM Thread Starter
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Re: Dual RL-P18 LLT for my 2000 cu ft HT soon

According to my recent readings, the EP-2500 is likely to produce the 750W you mentioned (Bruce) only with the dual 2 ohm configuration (in real world). I am even wondering if I should reconsider the amp choice .

Concerning the port velocity, I will kill this 26m/s limitation by using a 10" port, 80 cm long, but in a 600 L effective enclosure .

I wanted to ask about the insulation, what's the material to be used, and where.

I also wondering if carpetting the outside of the box is similar to insulation?

Thanks for your highly appreciated efforts Bruce!!

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post #16 of 183 Old 04-25-07, 11:26 AM
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Re: Dual RL-P18 LLT for my 2000 cu ft HT soon

Quote:
the EP-2500 is likely to produce the 750W you mentioned (Bruce) only with the dual 2 ohm configuration (in real world). I am even wondering if I should reconsider the amp choice
Well, the spec says 750 watts into 4 ohms (which is the resultant Znom of the dual 2 ohm coil driver wired in series). So the one amp in stereo would do both boxes. This doesn't seem like too bad an amp..... good bang for the bucks. Others would cost much more.

Dual RL-P18 LLT for my 2000 cu ft HT soon-ep2500-spec.jpg

Quote:
Concerning the port velocity, I will kill this 26m/s limitation by using a 10" port, 80 cm long, but in a 600 L effective enclosure
Yep, that seems to work. I stayed away from the 10" when I was messing around since it would demand the port is mounted vertically because of its long length and I was attempting to get a front mount (for no good reason). There's nothing wrong with a vertical mount (I don't think)....

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post #17 of 183 Old 04-25-07, 11:55 AM Thread Starter
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Re: Dual RL-P18 LLT for my 2000 cu ft HT soon

My boxes should have internal dimensions about 110 cm * 90 cm * 65 cm. The front baffle will be 65 * 90 cm, So I have 110 cm length to place the vent, with 80 cm I can have 25-30 cm for the port to breath. The closest walls to the port will be the side walls about 20 cm from each side.
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post #18 of 183 Old 04-25-07, 12:31 PM Thread Starter
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Re: Dual RL-P18 LLT for my 2000 cu ft HT soon

Yes Bruce, the Ep 2500 is rated 750 into 4 ohms, but I do want a configuration that can get the most out of the subs...(not that I will crank it loud all the time.... I have neighbours, but want to have this options) i.e 1000 watts for each sub min or more. The dual 2 ohm configuration should do this according to the EP-specs specs, but I have read here in this very forum and at AVS that the EP-2500 as a sub amp would not produce that much even at dual 2 ohms configuration. Here's a link
http://www.avsforum.com/avs-vb/showt...&&#post9598876

From the other side, here is my room responce, my room has some cancellations above 70 Hz, and doesn't support frequencies above 40 Hz that much, this is why I am looking for a strong amp. Fortunately the FBQ 2496 is here to manage things below 40 Hz.

Another thing I noted and I am very happy about is that: dual subs along the front wall will cancel the lateral room mode effect, which will let anyone seated have the same bass experience.

I am wondering how the ButtKicker BKA1000-4 compares to the EP-2500!??

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Dual RL-P18 LLT for my 2000 cu ft HT soon-room-respose-assuming-perfectly-flat-sub.jpg  


Last edited by Blaser; 04-25-07 at 01:09 PM.
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post #19 of 183 Old 04-25-07, 02:19 PM Thread Starter
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Re: Dual RL-P18 LLT for my 2000 cu ft HT soon

You can see the effect of the room on the subwoofer responnse here. Of course my sub is brickwall below 30 Hz, but the room is negatively affecting above 65 Hz.
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post #20 of 183 Old 04-25-07, 03:22 PM
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Re: Dual RL-P18 LLT for my 2000 cu ft HT soon

One person reported the BKA to be Equal to or superior to a single channel of an Ep2500 @ 4ohms. As it should be.

If you don't have a BFD for your sub, get one fast!
If you don't have REW, get it now!
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