Lilmike's Cinema F-20 - Page 34 - AVS Forum
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DIY Speakers and Subs > Lilmike's Cinema F-20
t6902wf's Avatar t6902wf 09:22 AM 01-06-2012
Quote:
Originally Posted by exojam View Post

t6902wf,

Just wondering why you are using a minisdsp when the Crown has built in DSP. You can download the software for the Crown, connect to it with a USB cable and go to town with it.

James

Sorry good catch Crown XLS1000 not XTi.

I am a big fan of the MiniDsp for its power and simplicity.

exojam's Avatar exojam 09:37 AM 01-06-2012
You just had me wondering there for a minute if I was missing something

James
MKtheater's Avatar MKtheater 10:02 AM 01-06-2012
t6902wf,
Running the subs in the room could be the cuprit. When I built my eD sono's for the first time I ran two of them and it was very little output. Once I put them into the corners of the room they were a whole new animal! Also, that room they are in is huge so getting the same spl will be more difficult than your room. The only way to really compare is put one in your room. The 20hz on up is really impressive so if they are not the room is just too big. These can hit 115 dbs outside at 20hz and if you are in a very large room it maybe the same indoors which means you will lose output from distance.
lilmike's Avatar lilmike 07:29 PM 01-06-2012
Quote:
Originally Posted by t6902wf View Post

We did some tests and the results were interesting and a little confusing.

As I mentioned the room is quite large, 8 foot drop ceiling 50 feet wide, 20 feet deep and open to the upstairs through a staircase.

I ran a simple 12 db / octave high pass at 20 hz as the only EQ, no Audyssey. We had a suck out at 40Hz that only got worse the further we moved the subs from the preferred placement. Watching content (Flight of the Phoenix and Transformers) we were getting 110 DB peaks 14' from the mouth of the subs. I was running it hot but not that hot. I was hoping for more. My theater has a single DTS10 in a small sealed room and I hit 116db peaks 14 feet away. Considering the room I may have been optimistic.

My questions: The 20hz high pass really started at 25 hz. Can I play with the slope and drop the hz so I don't lose that last 5hz? They were not strained but sounded a little tubby. I was going to add a low pass up at 120hz. I know adding a low pass to the DTS10 helped quite a bit. They both get a little erratic up high.

Sure, try a steeper slope

Quote:
Originally Posted by t6902wf View Post

Thankfully in my room I do not have a suck out. What is the best way to approach it EQ wise. Cut all around it and there by raising it relative to the rest of the signal?

Placement first, phasing/delay second, EQ third. I prefer to keep boosts to a minimum, cutting only where I have to. Measurements don't have to be picture perfect for a sub to sound great.

Quote:
Originally Posted by t6902wf View Post

The subs are in the room right now, they will move back behind the wall and be tucked right into the corner for the final install. I think that will help a little making them truly corner loaded. I seem to recall Tom Danley also talked about the boundaries around the mouth of the sub extending the horn? I could be wrong there but that is what I recall.

Any thoughts.


Sounds like a pretty big/open room. I have one of those too, so I know the challenge all too well. Still, I can crack 115 dB at my LP (~14' away) with a pair of T-6s, currently wired in series and fed by a BASH 500 (that's about 125 watts/sub). My room is one end of a 20'X40' area, open to both a stairway and a hallway, with a cathedral ceiling that is 12' high in the center.

Something is not right though. The F-20 puts a couple dBs and a half octave on the T-6. I sure hope placement addresses it. What's the real power being delivered to the subs to hit those levels? Have you looked at actual voltages at all?
mfagains's Avatar mfagains 12:24 AM 01-07-2012
Hi Lilmike;
How would the Mayhem 15" dual 2 ohm perform in this box wired series for 4ohms?


Dual 2 Ω
Re 1.4 Ω
Fs 36 Hz
Qms 5.97
Qes 0.24
Qts 0.23
Mms 261 g
Sd 810 cm^2
Vas 68.9 l
SPL 93.1 1W/1m
Bl 26.2 Tesla Meters
Xmax 30mm (one-way)
RMS 2500w

If it works..... would the diff in performance over the Dayton RSS390HF-4 be worth considering?

Thanks
lilmike's Avatar lilmike 10:48 AM 01-07-2012
Quote:
Originally Posted by mfagains View Post

Hi Lilmike;
How would the Mayhem 15" dual 2 ohm perform in this box wired series for 4ohms?


Dual 2 Ω
Re 1.4 Ω
Fs 36 Hz
Qms 5.97
Qes 0.24
Qts 0.23
Mms 261 g
Sd 810 cm^2
Vas 68.9 l
SPL 93.1 1W/1m
Bl 26.2 Tesla Meters
Xmax 30mm (one-way)
RMS 2500w

If it works..... would the diff in performance over the Dayton RSS390HF-4 be worth considering?

Thanks

Not a good fit at all, way too much motor.
mfagains's Avatar mfagains 08:08 PM 01-07-2012
Thanks Mike.....
t6902wf's Avatar t6902wf 06:50 AM 01-09-2012
We got them installed in the furnace / backroom. There was still some wiring and finish work to do so we did not fire them up. Quite an impressive sight installed.



I'll get better install photos when it is running with some plots.
t6902wf's Avatar t6902wf 11:10 AM 01-13-2012
We ran some tests last night. My friend who was coming from 12" and 15" 15 year old definitive subwoofers said in the beginning, I don't see how it could be better.

I played the cannon battle scene from Master and Commander and his son came running down the stairs and said he thought the floor was going to cave in upstairs, rookies.

The room is so large that I was shocked at how well it energized it. I am not going to be able to get a flat curve. There are 2 suckouts with the placement we had to use.

It is going to take a bit more tweaking but I can't image getting more bass for the $1,000 we have into it. It is also a hidden install. I'll get some photos of that also. Good Job Lilmike
staindrocks's Avatar staindrocks 09:48 PM 01-21-2012
Has anybody tried the Dayton DCS380-4 15" with this build? I was planning on ordering the RSS390HF-4 for either a THT build or a Cinema F-20 build, but i keep staring at the DCS380 for nearly a hundred bucks cheaper and now i'm stuck with what i want to do going forward. I already got a Bash 500w plate amp to power whatever build i end up going with. I've tried over and over again to model it in Hornresp, but as much as i've tried to learn how to do it, i simply don't know the ins and outs of the program well enough to get any conclusive results.

So i guess my question is... has anyone tried using this driver with this build yet? If not, can anyone tell me how it models with this build and/or what i'd be giving up by going with the cheaper driver?

*** Here's the specs on the DCS380-4
tony123's Avatar tony123 05:41 AM 01-22-2012
T6, that's fantastic! I love to hear the enthusiasm. It's fun!
jdanforth's Avatar jdanforth 02:14 PM 01-22-2012
I just bought two of these cabinets (from beastaudio) and they are HUGE! I can hardly wait for the drivers to come in from Partsexpress. I ordered the DVC385-88 driver.

In my theatre build thread I have been making little videos about the process. I whipped this one together in honor of this fantastic subwoofer and I thought I'd share it here. Thanks, lilmike, for the plans for this behemoth!


jdanforth's Avatar jdanforth 02:15 PM 01-22-2012
Quote:
Originally Posted by tony123 View Post

T6, that's fantastic! I love to hear the enthusiasm. It's fun!

Seconded! I can't WAIT!
lilmike's Avatar lilmike 04:59 PM 01-22-2012
Quote:
Originally Posted by staindrocks View Post

Has anybody tried the Dayton DCS380-4 15" with this build? I was planning on ordering the RSS390HF-4 for either a THT build or a Cinema F-20 build, but i keep staring at the DCS380 for nearly a hundred bucks cheaper and now i'm stuck with what i want to do going forward. I already got a Bash 500w plate amp to power whatever build i end up going with. I've tried over and over again to model it in Hornresp, but as much as i've tried to learn how to do it, i simply don't know the ins and outs of the program well enough to get any conclusive results.

So i guess my question is... has anyone tried using this driver with this build yet? If not, can anyone tell me how it models with this build and/or what i'd be giving up by going with the cheaper driver?

*** Here's the specs on the DCS380-4

I'm not aware of anyone using one of the Dayton Classic DCS380-4 drivers in an F-20. It will work, but is not quite as good a fit as the DVC or Reference HF. The response is "flat enough", but is a little lumpier than the MFW or other drivers. It should still be within +/-3 dB of flat from the corner to ~100 Hz.

The DCS380-4 driver will likely be excursion limited, rather than power limited, as the driver exceeds xmax in the model once more than 150 watts is applied. Granted - the cabinet is making over 110 dB (1M 2pi) at that point, so this might not be an issue for some. Compared to the DVC or Reference HF??? I've only built and tested this cabinet with the MFW, so I don't know for sure. According to the model, you're giving up that last 3 to 5 dBs. Might matter, might not, it all depends on what you're after.

If you build it, let me know how it works out. Measurements would be great.
lilmike's Avatar lilmike 05:04 PM 01-22-2012
Quote:
Originally Posted by jdanforth View Post

I just bought two of these cabinets (from beastaudio) and they are HUGE! I can hardly wait for the drivers to come in from Partsexpress. I ordered the DVC385-88 driver.

In my theatre build thread I have been making little videos about the process. I whipped this one together in honor of this fantastic subwoofer and I thought I'd share it here. Thanks, lilmike, for the plans for this behemoth!


Awesome!!!

Enjoy the subs.
superedge88's Avatar superedge88 09:21 PM 01-22-2012
I was trying to find this information throughout the thread, but I was wondering if the F-20 is similar to the THT in that you can make it as narrow as needed with only sacrificing a little bit of extension. So could I make an 18" wide F-20?
lilmike's Avatar lilmike 10:01 PM 01-22-2012
Quote:
Originally Posted by superedge88 View Post

I was trying to find this information throughout the thread, but I was wondering if the F-20 is similar to the THT in that you can make it as narrow as needed with only sacrificing a little bit of extension. So could I make an 18" wide F-20?

Yes, you can. Certain drivers handle it better.

Extension is not changed (set by the length), SPL drops though, and things are not quite as smooth.
superedge88's Avatar superedge88 10:22 PM 01-22-2012
Quote:
Originally Posted by lilmike View Post


Yes, you can. Certain drivers handle it better.

Extension is not changed (set by the length), SPL drops though, and things are not quite as smooth.

What driver would be recommended for a narrow f-20? I appreciate any help, I'm trying to integrate two horn subs into a built in shelving/entertainment center.
paulspencer's Avatar paulspencer 11:03 PM 01-22-2012
A very interesting project! Great of Mike to help people out with it, including plans.

Someone asked earlier about bass traps and corners. My experience has been that bass traps make a huge difference. I can't imagine not using them now. My first experiment made it sound like the bass had moved outdoors. Horns in the corner and bass traps in the corner can be tricky. In my case I'm planning some horn subs under the floor, then a bass trap over it. The corner will still work like a corner in terms of bass loading, the sub will load into the tri-corner. Bass traps don't absorb all bass in the room, they damp the modal ringing, resulting in much tighter bass. Bass traps can be made to blend into a room and not dominate, but size does matter. Bulkhead traps are also an option. I'd encourage people to try them and find out if you can find a way to get them into your room. An experiement with couch cushions and mattresses in corners can be illuminating. It all started there for me.

The comments in the GTG about the F20 are curious. I can't help but wonder if the F20 was used in a way that put it at an unfair disadvantage. Could it be that it needed a lower crossover point? I'm looking at doing something similar, but it only needs to get up to 40 Hz.

When I model the F20 in hornresp, I find that to my surprise I can get a bit more efficiency with a tapped horn of similar size (using different drivers). The tapped horn seems to need more careful filtering (HP) while the FLH has the sealed chamber as protection. The FLH also can go up a bit higher, but the TH becomes more seriously limited in the top end, and really only wants to be an LFE monster. Not a problem in my case because I have 18" pro woofers above 40, I'm just looking for a way to get more juice out of a pair of Rythmik 12" subs.

Again great work on this one Mike!
staindrocks's Avatar staindrocks 11:27 PM 01-22-2012
Quote:
Originally Posted by lilmike View Post

I'm not aware of anyone using one of the Dayton Classic DCS380-4 drivers in an F-20. It will work, but is not quite as good a fit as the DVC or Reference HF. The response is "flat enough", but is a little lumpier than the MFW or other drivers. It should still be within +/-3 dB of flat from the corner to ~100 Hz.

The DCS380-4 driver will likely be excursion limited, rather than power limited, as the driver exceeds xmax in the model once more than 150 watts is applied. Granted - the cabinet is making over 110 dB (1M 2pi) at that point, so this might not be an issue for some. Compared to the DVC or Reference HF??? I've only built and tested this cabinet with the MFW, so I don't know for sure. According to the model, you're giving up that last 3 to 5 dBs. Might matter, might not, it all depends on what you're after.

If you build it, let me know how it works out. Measurements would be great.

If i do decide to build it with the DCS380-4, i'll start a build thread and document how it goes. So you'll definitely be able to see how it works out. I'll also be happy to provide measurements, as long as i get some help with it... hopefully i'll be more up to speed by the time i finish the build, but i'm sure i'll still need some help with the measuring stuff.

EDIT:
lilmike, what kind of flare do you choose in Hornresp for this build? And is it the same flare that everyone uses for all of the diy horn sub builds here?
lilmike's Avatar lilmike 01:09 AM 01-23-2012
Quote:
Originally Posted by staindrocks View Post

If i do decide to build it with the DCS380-4, i'll start a build thread and document how it goes. So you'll definitely be able to see how it works out. I'll also be happy to provide measurements, as long as i get some help with it... hopefully i'll be more up to speed by the time i finish the build, but i'm sure i'll still need some help with the measuring stuff.

EDIT:
lilmike, what kind of flare do you choose in Hornresp for this build? And is it the same flare that everyone uses for all of the diy horn sub builds here?

I used multiple parabolic flares, because that is what I drew and what I built.
staindrocks's Avatar staindrocks 01:47 AM 01-23-2012
Quote:
Originally Posted by lilmike View Post

I used multiple parabolic flares, because that is what I drew and what I built.

Is there an easy way to explain what the differences are between the three horn flare options(conical, exponential, and parabolic) and how they relate to the actual build? Hopefully, you understand what i'm trying to ask. What(or where) on your horn would you build differently when choosing a conical vs exponential vs parabolic flare?
lilmike's Avatar lilmike 09:16 AM 01-23-2012
Quote:
Originally Posted by staindrocks View Post

Is there an easy way to explain what the differences are between the three horn flare options(conical, exponential, and parabolic) and how they relate to the actual build? Hopefully, you understand what i'm trying to ask. What(or where) on your horn would you build differently when choosing a conical vs exponential vs parabolic flare?

In a nutshell (as I understand the geometry differences):

Conical has no parallel sides, but all sides are linear for a given flare.

Parabolic has two parallel sides, and all sides are linear for a given flare.
(in a typical cabinet, this is what gets built)

Exponential has no parallel sides and no sides are linear for a given flare.

In other words - Parabolic = simplest to fold and build, conic is more complex, and exponential is a real challenge.

Multiple flare rates adds another level of complexity, but often results in a better performing horn.

Exponential flares can be approximated with multiple conic or parabolic sections.
beastaudio's Avatar beastaudio 09:37 AM 01-23-2012
Quote:
Originally Posted by jdanforth View Post

I just bought two of these cabinets (from beastaudio) and they are HUGE! I can hardly wait for the drivers to come in from Partsexpress. I ordered the DVC385-88 driver.

In my theatre build thread I have been making little videos about the process. I whipped this one together in honor of this fantastic subwoofer and I thought I'd share it here. Thanks, lilmike, for the plans for this behemoth!


Well I recognize those guys haha...Cant wait to hear your thoughts on these guys I know I loved em.
LTD02's Avatar LTD02 07:48 PM 01-26-2012
found any drivers that perform better than the standard model lately?
paulspencer's Avatar paulspencer 07:56 PM 01-26-2012
I may soon be building one of these, or similar, and comparing to a tapped horn of similar size with two Rythmik kits. That should be interesting.
LTD02's Avatar LTD02 08:02 PM 01-26-2012
paul, be sure to brace them well as in the updated build plan. no reason to lose any energy to cab vibrations. look forward to your build!
paulspencer's Avatar paulspencer 08:31 PM 01-26-2012
Antripodean is keen to build one, I'm keen to build something like this:

http://redspade-audio.blogspot.com/2...-horn-sub.html



I've seen a CAD drawing with the bracing and I'd be inclined to brace it a bit more actually.

Antripodean has some AE drivers (not the standard ones) that we might try in it. Maybe also a dual driver version. I need another pair of hands to do it so it should work out well, we both build the pair. We'd probably put on a bass GTG here, measure them and do a report. The Rythmik subs are very good on their own, I'm a bit curious what happens to them in a design like this. On their own they are equal to the best I've heard, only beaten in output. Do they simply get louder? Do they sound even better? Or do they lose something in being "turbo charged?"

I live near a train line where diesel trains go past in the evening sometimes. I might be watching a movie and hear this rumble. I'll pause the movie. Is it the movie or the trains? I can't tell the difference with the Rythmik subs.
lilmike's Avatar lilmike 09:15 PM 01-26-2012
Quote:
Originally Posted by LTD02 View Post

found any drivers that perform better than the standard model lately?

Not yet. Still looking.

Kicker's new 2-ohm Comp 15 looks decent in the model, and might make a decent value option. It's a little light on throw compared to some of the other choices out there, but models pretty good. Might be tough to seal the driver to the cabinet though, need to take a closer look at it when I get a chance. No first-hand experience with any of the Kicker subs yet.
lilmike's Avatar lilmike 09:35 PM 01-26-2012
Quote:
Originally Posted by paulspencer View Post

Antripodean is keen to build one, I'm keen to build something like this:

http://redspade-audio.blogspot.com/2...-horn-sub.html


Cool design. I did something similar as far as layout goes a few years back. It works very well.

Quote:
Originally Posted by paulspencer View Post

I've seen a CAD drawing with the bracing and I'd be inclined to brace it a bit more actually.

According to some testing and observations made by others, more may not be better, at least when it comes to bracing. Testing by ScreamersUSA and Jbell over at DIYAudio found that solid braces cost dBs within the passband, while windowed ones did not.

If you are considering full-length braces, remember - the corners are solid, the panel midpoints and unsupported ends are the weak parts. Bracing in a corner is a waste of wood as far as strength and vibration resistance goes. If the reflector's purpose is to block off extra volume in the corner, that's another story.

Honestly - the test mule pounded away doing PA duty all night long at a party with one of the mains sitting on top of it. No dancing speakers, no spilled drinks, nothing fell over, no drama at all. The bracing might matter at extremely high levels, or with sustained sine waves. If you want to add it - by all means do so.

Quote:
Originally Posted by paulspencer View Post

Antripodean has some AE drivers (not the standard ones) that we might try in it. Maybe also a dual driver version. I need another pair of hands to do it so it should work out well, we both build the pair. We'd probably put on a bass GTG here, measure them and do a report. The Rythmik subs are very good on their own, I'm a bit curious what happens to them in a design like this. On their own they are equal to the best I've heard, only beaten in output. Do they simply get louder? Do they sound even better? Or do they lose something in being "turbo charged?"

Good luck with the builds. As far as results, I'll be honest - I don't really know. Let us know what you think when you get some results. Seems to me that a great driver, in a cabinet that is well suited to it, should result in an exceptional combination - whatever alignment that cabinet presents.

Biggest thing for me is the reduction in distortion at the same SPL level. It is not that I listen any louder, I simply enjoy the sound more, because the subs are not calling attention to themselves by failing to reproduce the signal that they're sent. I'm no blind evangelist. As soon as I find something better, I'll quit building horns. For now, even with the inherent compromises, I like horns, tapped or conventional.

Quote:
Originally Posted by paulspencer View Post

I live near a train line where diesel trains go past in the evening sometimes. I might be watching a movie and hear this rumble. I'll pause the movie. Is it the movie or the trains? I can't tell the difference with the Rythmik subs.

Nice.
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