4 cinema F-20's - Page 7 - AVS Forum
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DIY Speakers and Subs > 4 cinema F-20's
maxmercy's Avatar maxmercy 11:32 AM 07-21-2011
DR200s will provide good suppprt above 125-150hz.....and efficiency drops below that. But you are talking a drop from 100+db sensitivity to the 90s....

They will be crazy loud and REQUIRE EQ.

Not sure if they will provide all the midbass you need.....but in your enclosed room, they may perform well....

Hope they work well, they are a VERY economical way to get output, like most of BFMs designs....but they have built in compromises, like all designs.

JSS

MKtheater's Avatar MKtheater 11:39 AM 07-21-2011
Yeah, I understand. My processor I have coming has built in EQ(PEQ) that I can manually adjust. One of the first things I will do is raise the XO to 120-150hz and see how the F-20's sound up that high. Of course I will post results and graphs.
coctostan's Avatar coctostan 12:16 PM 07-21-2011
MK, I can't remember which JBL cinema speakers you used. Were they 4722's? Did you use factory crossover specs? Did you ever get the 3-way JBL clones working?
MKtheater's Avatar MKtheater 12:38 PM 07-21-2011
Quote:
Originally Posted by coctostan View Post

MK, I can't remember which JBL cinema speakers you used. Were they 4722's? Did you use factory crossover specs? Did you ever get the 3-way JBL clones working?

I used the 3622N, a DIY hybrid of the 3731, and finally the 4675C. The 3622N was a passive speaker, the 3731 I never kept long enough to get perfect and the 4675 came with amps that had the built in XO for them and worked great. It is the HF and tone that I like about the M&K's. They just sound loud and clear with very dynamic swings. I am using Ada amps on them if that means anything.
coctostan's Avatar coctostan 12:44 PM 07-21-2011
Among the JBL's which did you prefer?
MKtheater's Avatar MKtheater 01:00 PM 07-21-2011
Quote:
Originally Posted by coctostan View Post

Among the JBL's which did you prefer?

There were trade offs and I picked the one that wowed me the most. I prefer the 4675C's for their awesome mid bass and huge dynamic sound. The 3731's actually had better highs. I guess if I built a hybrid it would do wonders. The M&K's have that HF energy and sizzle but lack some mid bass and the size of the sound is not as big. In my room small speakers are at an advantage and the big cinema are at a disadvantage. Here are 2 examples while watching movies. They both play reference easily, they both play loud and clear. The JBL's sound bigger and on certain scenes more midbass come thru(resident evil 4 shows this). However, during sword play the JBL's have a loud clank but the M&K's have a loud clank with sizzle or extended response. It makes the clank more dynamic sounding yet both are the same spl. It makes you blink. You guys have to remember the last time I had M&K S-5000's I had a wimpy sub system in comparison. During gunshots the same things happens. They seem more dynamic but I know they are not.
MKtheater's Avatar MKtheater 01:39 PM 07-21-2011
Just another tid bit, I just added 4 more 20 amp circuits making the theater having 8 20 amp circuits and one 15 amp circuit. Just in case I run some RE-XXX's.
BiGBADDABOOM's Avatar BiGBADDABOOM 01:40 PM 07-21-2011
FP14000 clone do ok on 20amp? I can't remember, can you push that much through the XXXs?
MKtheater's Avatar MKtheater 02:11 PM 07-21-2011
Quote:
Originally Posted by BiGBADDABOOM View Post

FP14000 clone do ok on 20amp? I can't remember, can you push that much through the XXXs?

Yes and no, I think the RE-XXX is 2000 watts rms.
BiGBADDABOOM's Avatar BiGBADDABOOM 02:13 PM 07-21-2011
Guess you'd be good with an MA5050 to drive a pair.
MKtheater's Avatar MKtheater 02:18 PM 07-21-2011
Quote:
Originally Posted by BiGBADDABOOM View Post

Guess you'd be good with an MA5050 to drive a pair.

Yep, but the clone is just so cool. Anyways, the F-20's are plenty for me. I would say running them 3 db's hot is almost too much and need to run them flat with a movie like Battle:LA. Damn that movie was awesome!! Never felt bass like that before with so many scenes.
tony123's Avatar tony123 02:22 PM 07-21-2011
I think you're spot on in your comments regarding the DTS10's being less active than other subs. I don't understand why that would happen, but I've always felt that way too. Other subs make their prescense known more often. The Danley, for some reason, can disappear for most of a movie and then tear the room apart. Is it the Danley? or is it my particular configuration? I don't know.
MKtheater's Avatar MKtheater 02:30 PM 07-21-2011
Quote:
Originally Posted by tony123 View Post

I think you're spot on in your comments regarding the DTS10's being less active than other subs. I don't understand why that would happen, but I've always felt that way too. Other subs make their prescense known more often. The Danley, for some reason, can disappear for most of a movie and then tear the room apart. Is it the Danley? or is it my particular configuration? I don't know.

This is what I mean by the F-20's having the same delivery as the DTS-10's. They are pretty silent and then wham!!! bass waves ripping thru you. The F-20's have more midbass energy but that has to do with the ease of setup and not needed much EQ to flatten them out. The DTS-10's needed more attention for proper placement and remember I am using 4 subs and not 2 but 4 subs is still cheaper or as cheap as 1 dts-10 kit which is what makes these so great.
CZ Eddie's Avatar CZ Eddie 03:25 PM 07-21-2011
THT and my DTS are both like that also.
kryptonitewhite's Avatar kryptonitewhite 11:51 PM 07-21-2011
Ricci dumped 3kW into his free air from 30Hz on up.

If the Maelstrom-X handled 3kW, then I''d think the XXX could handle even more. Kevin repeatedly stated the MXs would take 3k all day.
Maxjr's Avatar Maxjr 05:13 AM 07-22-2011
MK, Your F20's came out great! I don't think it was mentioned before, were they primered first, or just painted flat black directly on the ply?
MKtheater's Avatar MKtheater 06:58 AM 07-22-2011
Quote:
Originally Posted by Maxjr View Post

MK, Your F20's came out great! I don't think it was mentioned before, were they primered first, or just painted flat black directly on the ply?

eD built them and I think they just put paint on the ply.
MKtheater's Avatar MKtheater 06:59 AM 07-22-2011
Quote:
Originally Posted by kryptonitewhite View Post

Ricci dumped 3kW into his free air from 30Hz on up.

If the Maelstrom-X handled 3kW, then I''d think the XXX could handle even more. Kevin repeatedly stated the MXs would take 3k all day.

Yeah, I am sure you are right but the LG clone could run 4 RE:XXX's.
coctostan's Avatar coctostan 07:03 AM 07-22-2011
Quote:
Originally Posted by kryptonitewhite View Post

Ricci dumped 3kW into his free air from 30Hz on up.

If the Maelstrom-X handled 3kW, then I''d think the XXX could handle even more. Kevin repeatedly stated the MXs would take 3k all day.

Thermally, these drivers will handle significant amounts of peak power with actual content. The ratings of 2000w or whatever they spec RMS is a constant power level they can sustain over a long period of time. That is something none of us do unless we sit there with a sine wave pegged for an hour. I guess I could see you doing that KW.

If MK wants to do a couple XXX's, he should first size the box for the appropriate excursion control. I don't have the models in front of me, but I think 10 cuft per driver is good. I don't recall how much power that takes to hit XMAX though, its on another computer.
MKtheater's Avatar MKtheater 07:12 AM 07-22-2011
Quote:
Originally Posted by coctostan View Post

Thermally, these drivers will handle significant amounts of peak power with actual content. The ratings of 2000w or whatever they spec RMS is a constant power level they can sustain over a long period of time. That is something none of us do unless we sit there with a sine wave pegged for an hour. I guess I could see you doing that KW.

If MK wants to do a couple XXX's, he should first size the box for the appropriate excursion control. I don't have the models in front of me, but I think 10 cuft per driver is good. I don't recall how much power that takes to hit XMAX though, its on another computer.

Yes, 9-10 cubic foot was the number I have been given. I am still debating if I really need to raise the 10hz and under 10db's or not because it is crazy in here. I wonder if I am getting more spl's down low than my gear is saying because it sure feels strong. If I do upgrade it will be RE:XXX's but maybe the 12's because I don't have any room for big boxes. I guess I could put the 2 subs on top of my F-20's lying across.
kryptonitewhite's Avatar kryptonitewhite 07:19 AM 07-22-2011
WinISD puts it in 22.5 cu ft, 800 watts brings it to 56mm. 10 cu ft 1040 watts brings it to the same.


kryptonitewhite's Avatar kryptonitewhite 07:24 AM 07-22-2011
9 cu ft, 3000 watts, no factoring crossovers or electronic roll off


I need to fix my photobucket uplaod settings, cant see anything
chrapladm's Avatar chrapladm 07:50 AM 07-22-2011
How much are these XXX drivers?
coctostan's Avatar coctostan 07:56 AM 07-22-2011
Quote:
Originally Posted by MKtheater View Post

Yes, 9-10 cubic foot was the number I have been given. I am still debating if I really need to raise the 10hz and under 10db's or not because it is crazy in here. I wonder if I am getting more spl's down low than my gear is saying because it sure feels strong. If I do upgrade it will be RE:XXX's but maybe the 12's because I don't have any room for big boxes. I guess I could put the 2 subs on top of my F-20's lying across.

If you are short on space, go with 1-2 LMS 5400's. You are really just looking for as much displacement as you can get from a box that fits. The XXX is the displacement king, but it requires a slightly larger box to take advantage of its huge displacement.

But in all honesty, you are kind of chasing your tail. It would have been more economical to just buy 4 LMS's, put them in sealed boxes and be done with it. It would outdo the 4 F20's + 2 LMSs. If you add 2 LMSs to your F20's, it would be interesting to turn off, the F20s, re-eq and run it to see if those would be adequate in your room.

With your solid walls, you are getting a true 1/8 space effect below probably 40-50hz no matter where you place the sub and you probably get ~12db over what the models show. That isn't even taking into account pressure gain which is debated by some. Two LMS 5400's model to about 108db @ 10hz at xmax. Add in the 12db for 1/8 space and you have 120db. Four of them will get you to 126db.

Have you tried running 1 or 2 F20s to see how that sounds? You wouldn't get much below 20hz, but they would probably still be loafing above 20hz.
MKtheater's Avatar MKtheater 08:06 AM 07-22-2011
Quote:
Originally Posted by coctostan View Post

If you are short on space, go with 1-2 LMS 5400's. You are really just looking for as much displacement as you can get from a box that fits. The XXX is the displacement king, but it requires a slightly larger box to take advantage of its huge displacement.

But in all honesty, you are kind of chasing your tail. It would have been more economical to just buy 4 LMS's, put them in sealed boxes and be done with it. It would outdo the 4 F20's + 2 LMSs. If you add 2 LMSs to your F20's, it would be interesting to turn off, the F20s, re-eq and run it to see if those would be adequate in your room.

With your solid walls, you are getting a true 1/8 space effect below probably 40-50hz no matter where you place the sub and you probably get ~12db over what the models show. That isn't even taking into account pressure gain which is debated by some. Two LMS 5400's model to about 108db @ 10hz at xmax. Add in the 12db for 1/8 space and you have 120db. Four of them will get you to 126db.

Have you tried running 1 or 2 F20s to see how that sounds? You wouldn't get much below 20hz, but they would probably still be loafing above 20hz.

I agree, I do get a max of 6 db's every time I double the subs no matter where I put them(except center of the room). I do believe 2 XXX's or 2 LMS 5400's would be enough for my room, I do love my room. There is no way that 2 XXX's or 2 LMS's would compete with 4 F-20's above 20hz but again reference levels are only 115 db peaks with some 120 db's in there once in a while on big bass movies(using bass management).
LTD02's Avatar LTD02 08:31 AM 07-22-2011
"But in all honesty, you are kind of chasing your tail. It would have been more economical to just buy 4 LMS's, put them in sealed boxes and be done with it. It would outdo the 4 F20's + 2 LMSs."

?
MKtheater's Avatar MKtheater 09:13 AM 07-22-2011
Quote:
Originally Posted by LTD02 View Post

"But in all honesty, you are kind of chasing your tail. It would have been more economical to just buy 4 LMS's, put them in sealed boxes and be done with it. It would outdo the 4 F20's + 2 LMSs."

?

Yeah, I understand the question mark because 4 LMS would have cost over 7x more money to have more 15hz and below because above 20hz it would be a challenge.
BiGBADDABOOM's Avatar BiGBADDABOOM 09:33 AM 07-22-2011
I think he's saying adding two LMS's at this point is chasing your tail because 4 LMS's to begin with would have outdone the 4 F20s there now and an additional two LMS's for support.

Or maybe I just made this more confusing.

Cost of drivers for the 4 F20's and 2 LMS's is only $2130 though. 4 LMS's would be $3700. Then you add some more expense in amps as well.

But of course, he's already been there really. 4 LMS's is pretty much right on par with the 8 x eD 18's or Chase 18's he had and the same ballpark for costs. SQ is meaningless because he's got so much headroom all of these drivers are loafing during a film at reference.

These four F20's were probably less than $1K and walk all over his previous setups from 20Hz and up.

To go from there to spending ~$2600 on two LMS's and amp to get some additional low end support is a large jump. I think as much as MK likes overkill, he also likes the hunt for high value unique solutions to these... "problems".
kryptonitewhite's Avatar kryptonitewhite 10:12 AM 07-22-2011
Quote:
Originally Posted by BiGBADDABOOM View Post

he also likes the hunt for high value unique solutions to these... "problems".


BiGBADDABOOM's Avatar BiGBADDABOOM 10:17 AM 07-22-2011

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