Lilmike's Cinema F-20 - Page 40 - AVS Forum
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DIY Speakers and Subs > Lilmike's Cinema F-20
lilmike's Avatar lilmike 02:06 PM 03-22-2012
Quote:
Originally Posted by 04FLHRCI View Post

Mike,

Were you able to make saw dust last weekend?

Larry

Yup. Hope to make some more tonight....

lilmike's Avatar lilmike 02:13 PM 03-22-2012
Quote:
Originally Posted by dutchswan0311 View Post

I heard one of my F20s for the first time last night. Unfortunately, I didn't have any speakers to accompany it and so I listened to a Creed song and only heard the lower frequencies on the CD lol. I'm going to finish up the first two 1pi speakers and install another woofer into the second F20, so I will listen to some tunes with a pair of each tonight. My components for the 4pis are in transit....so there will be some extensive testing in my near future (and I am still working on the other two F20s). I wish I could clone myself for the extra man power.

Quick Question: Is it better to crank the amps all the way up, and adjust the volume from the receiver, or is it better to dial down the amps and crank up the receiver? How does one even know if they are starting to push the limits of their driver? The amps have lights on the fronts to tell you if you are near clipping...but what do you go on for the woofers? I just don't want to get careless and ruin a new woofer.

(I am driving a pair of 500W 390HFs with an Crown XLS1000 @ 350W x 2 into 4 ohms)

P.S. My preamp AVR's volume is measured in units "0 - 100". I had one F20 with the amp's channel turned all the way up, and when I turned the AVR up to around "60", my whole house was shaking....and it's 4,600 sqft! I can't wait to hear two tonight... Nay I can't wait to hear four of them in a couple of weeks!

Gain structure is usually set so that the receiver controls the master volume. I generally adjust the sub amp gain so that the level is matched with the mains, then leave it alone.

You should not hurt the drivers with that amp so long as you don't see clip lights on the amps. You should be able to hear the driver complaining if you're pushing it too hard. I heard a few unpleasant noises from my MFW-15 during testing when I messed up while setting the levels, but it survived the abuse just fine. Excursion should not be a problem, so long as you are not playing sine waves at ~20 Hz.

My F-20 visibly flexed all of the windows on one side of my house while I was measuring distortion. I was measuring it outside, and the house was behind me.
thaddeussmith's Avatar thaddeussmith 02:28 PM 03-22-2012
Quote:
Originally Posted by dutchswan0311 View Post

I heard one of my F20s for the first time last night. Unfortunately, I didn't have any speakers to accompany it and so I listened to a Creed song and only heard the lower frequencies on the CD lol. I'm going to finish up the first two 1pi speakers and install another woofer into the second F20, so I will listen to some tunes with a pair of each tonight. My components for the 4pis are in transit....so there will be some extensive testing in my near future (and I am still working on the other two F20s). I wish I could clone myself for the extra man power.

Quick Question: Is it better to crank the amps all the way up, and adjust the volume from the receiver, or is it better to dial down the amps and crank up the receiver? How does one even know if they are starting to push the limits of their driver? The amps have lights on the fronts to tell you if you are near clipping...but what do you go on for the woofers? I just don't want to get careless and ruin a new woofer.

(I am driving a pair of 500W 390HFs with an Crown XLS1000 @ 350W x 2 into 4 ohms)

P.S. My preamp AVR's volume is measured in units "0 - 100". I had one F20 with the amp's channel turned all the way up, and when I turned the AVR up to around "60", my whole house was shaking....and it's 4,600 sqft! I can't wait to hear two tonight... Nay I can't wait to hear four of them in a couple of weeks!

using my oAudio 500w amp and Denon 3808ci with Audyssey i had to set the amp gain at the 2 o'clock position for my channel level to be within the recommended -3 db setting through Audyssey detection (vs -9 to -12 when i had the amp cranked higher). After that, I have not yet needed to push the gain past 6 o'clock to overwhelm my room and get big fat smiles.
dutchswan0311's Avatar dutchswan0311 02:28 PM 03-22-2012
My house "buzzed" from everything around the house rattling. I will need to figure out how to prevent this at the winery's dinner theater...granted the group of four will be pointed at a 23,000 cubic foot room.
stormwind13's Avatar stormwind13 05:29 PM 03-22-2012
I run my f20 pair off of a crown xls-1500 with no issues. They both have the MFW-15 driver in them.
dutchswan0311's Avatar dutchswan0311 05:56 PM 03-22-2012
Quote:
Originally Posted by stormwind13 View Post

I run my f20 pair off of a crown xls-1500 with no issues. They both have the MFW-15 driver in them.

Got the second one connected today. With the XLS1000 maxed out on both channels, the pair of F20 start to clip when I have the AVR set at 75% volume. I think Mike would say going to the XLS1500 for its 500+ Watts would not make a noticeable difference. Right?

(Pretty cool by the way...cant wait to get the other two built
lilmike's Avatar lilmike 08:29 PM 03-22-2012
Quote:
Originally Posted by dutchswan0311 View Post

Got the second one connected today. With the XLS1000 maxed out on both channels, the pair of F20 start to clip when I have the AVR set at 75% volume. I think Mike would say going to the XLS1500 for its 500+ Watts would not make a noticeable difference. Right?

(Pretty cool by the way...cant wait to get the other two built

I even showed you the math....but I'll say it again.

There is not an appreciable difference.

Are the F-20s distorting at all, or is it just the clip lights?

If it is just the clip lights, the next thing to figure out is what's clipping. Are you clipping the inputs or the outputs, or is your AVR clipping?

I'd put my money on the AVR clipping, unless it has XLRs, and even then it may still be the culprit.
dutchswan0311's Avatar dutchswan0311 09:04 PM 03-22-2012
There are five lights on the front of the amps for each channel. Three are green, the fourth is red and is labeled "clip", the fifth is red and is labeled "thermal". With the amps set to full power (allegedly 350W for each channel at 4 ohms) the fourth light labeled "clip" starts to flicker when the volume of the AVR reaches 75% - 80% while playing Katy Perry's ET...and so I have not pushed them past that point yet. The subs themselves sound fine at that level. I am just new to this and don't know what I don't know...but I do know I don't want to break anything. I have yet to hear the subs distort or sound bad. The AVR is connected to the amps with RCA cables.
stormwind13's Avatar stormwind13 10:32 PM 03-22-2012
even when my amp gets to clipping stage, I hear no bad noises from the horns. A little more tweaking from my avr and it was good to go. Generally if my amp is clipping, I'm listening at an uncomfortable level and need to turn it down anyways. And when it does clip, it's usually only for a split second and nothing more.
thaddeussmith's Avatar thaddeussmith 03:32 AM 03-23-2012
Quote:
Originally Posted by dutchswan0311 View Post

There are five lights on the front of the amps for each channel. Three are green, the fourth is red and is labeled "clip", the fifth is red and is labeled "thermal". With the amps set to full power (allegedly 350W for each channel at 4 ohms) the fourth light labeled "clip" starts to flicker when the volume of the AVR reaches 75% - 80% while playing Katy Perry's ET...and so I have not pushed them past that point yet. The subs themselves sound fine at that level. I am just new to this and don't know what I don't know...but I do know I don't want to break anything. I have yet to hear the subs distort or sound bad. The AVR is connected to the amps with RCA cables.

what is the channel level set to in your AVR for the sub? -12? 0? +12? I'm learning out to setup my Behringer Feedback Destroyer for PEQ and in all of the guides they recommend setting the LFE channel level as low as possible to keep the BFD just on the edge between yellow and red; something to do with mixing pro and consumer gear.
NicksHitachi's Avatar NicksHitachi 04:53 AM 03-23-2012
Quote:
Originally Posted by thaddeussmith View Post


what is the channel level set to in your AVR for the sub? -12? 0? +12? I'm learning out to setup my Behringer Feedback Destroyer for PEQ and in all of the guides they recommend setting the LFE channel level as low as possible to keep the BFD just on the edge between yellow and red; something to do with mixing pro and consumer gear.

Yes check trim on sub channel. If you want your mains to play louder you could lower the trim on the sub so the mains play louder before the sub clips.

General consensus is clip lights are bad, so avoid them if you can.

I max out the knob on the pro amp and turn down the controller until i dont see any clipping on epic bass sequences like WOTW or Inception.

There is an interesting poll on gain structure in the DIY speakers forum and some wise men have chimed in on how much red lights they tolerate in their setup. Cant post link on phone though.....
dutchswan0311's Avatar dutchswan0311 07:07 AM 03-23-2012
Quote:
Originally Posted by stormwind13 View Post

even when my amp gets to clipping stage, I hear no bad noises from the horns. A little more tweaking from my avr and it was good to go. Generally if my amp is clipping, I'm listening at an uncomfortable level and need to turn it down anyways. And when it does clip, it's usually only for a split second and nothing more.

You are describing what I was seeing. I did not hear anything bad, and most of the bass was barely making the 3rd green light flicker....but at certain peaks the red "clip" light would flicker. And yes...they were pretty loud with the AVR set at that 75% volume level. I put the soundtrack in for "The Last of the Mohicans" and the title theme has a couple of spots that seem to share some kind of harmonic properties with the floor in my house and made it vibrate in a really cool way.

While most patrons (not to mention moms/wifes) would never want to listen to music at this level for sustained periods, the primary use for these speakers/subs is cinema. You DO want explosions and the occasional sound affect to utilize the set of four F20s to their full capability, as that will provide the theater with a real presence at those special moments in movies.
beastaudio's Avatar beastaudio 07:57 AM 03-23-2012
with two more f-20's for the total of 4, you are going to gain an additional 6db's of headroom. this will, assuming the level you are playing them at right now is good for you, take the clipping out of the question if I had to guess...

Another thing too, have you looked at EQing them yet? there may be a peak that needs to be tamed with EQ. Did you ever say what your sub trim level on the AVR is set to?
dutchswan0311's Avatar dutchswan0311 08:15 AM 03-23-2012
Quote:
Originally Posted by beastaudio View Post

with two more f-20's for the total of 4, you are going to gain an additional 6db's of headroom. this will, assuming the level you are playing them at right now is good for you, take the clipping out of the question if I had to guess...

Another thing too, have you looked at EQing them yet? there may be a peak that needs to be tamed with EQ. Did you ever say what your sub trim level on the AVR is set to?

I will check the sub trim level on the AVR tonight. I am clearly at the beginning stages of learning where everything should be set. I have not done ANY EQ yet. I basically have wired everything together, turned it on...and cranked it up (I didn't want to do TOO much EQ at this point, as everything is setting in the music alcove in my house. The real EQ will be done when everything is in its final resting place at the winery.)

I did low pass the subs at 99Hz using that function on the amps. I thought the amps could set the lowpass and the highpass...but it can only do one or the other. I will have to figure out how to highpass them to 20Hz. I will say Black Eye Peas really know how to dig deep with their bass.
nube's Avatar nube 08:46 AM 03-23-2012
Quote:
Originally Posted by dutchswan0311 View Post

My house "buzzed" from everything around the house rattling. I will need to figure out how to prevent this at the winery's dinner theater...granted the group of four will be pointed at a 23,000 cubic foot room.

And, I think it's important to remember that you're not going to be playing exclusively 5 star bass movies. I assume your dinner theater will show any and all genres. Though, the capability for excessive bass will be there, and so it would definitely be worth your while to try to get the vibrations fixed before going live.

I am curious - how well mortared is the rock exterior of your building? And, are you planning to secure all ducting and conduit, and going the double-drywall + green glue and wall/ceiling treatments route?

As to lowpass and high pass, the low pass should be taken care of by your AVR - it'll recommend (or default to) 80hz but that's user-adjustable. That frees up your amps to highpass at 21hz or whatever the recommended setting is for the F-20s.
NicksHitachi's Avatar NicksHitachi 08:51 AM 03-23-2012
Quote:
Originally Posted by dutchswan0311 View Post

I will check the sub trim level on the AVR tonight. I am clearly at the beginning stages of learning where everything should be set. I have not done ANY EQ yet. I basically have wired everything together, turned it on...and cranked it up (I didn't want to do TOO much EQ at this point, as everything is setting in the music alcove in my house. The real EQ will be done when everything is in its final resting place at the winery.)

I did low pass the subs at 99Hz using that function on the amps. I thought the amps could set the lowpass and the highpass...but it can only do one or the other. I will have to figure out how to highpass them to 20Hz. I will say Black Eye Peas really know how to dig deep with their bass.

I found this writeup very informative and helpful. It'll take a couple reads for it all to sink in and make sense, or it did me.
dutchswan0311's Avatar dutchswan0311 09:38 AM 03-23-2012
Quote:
Originally Posted by nube View Post

And, I think it's important to remember that you're not going to be playing exclusively 5 star bass movies. I assume your dinner theater will show any and all genres. Though, the capability for excessive bass will be there, and so it would definitely be worth your while to try to get the vibrations fixed before going live.

I am curious - how well mortared is the rock exterior of your building? And, are you planning to secure all ducting and conduit, and going the double-drywall + green glue and wall/ceiling treatments route?

As to lowpass and high pass, the low pass should be taken care of by your AVR - it'll recommend (or default to) 80hz but that's user-adjustable. That frees up your amps to highpass at 21hz or whatever the recommended setting is for the F-20s.

The vibrations were in my house...and was caused by drawers in the kitchen and pictures on the wall lol. The dinner theater at the winery will be setup specificially for this application and should not have the same issues.

The ceiling of the rooms in which the dinner theater is located will have drop ceilings (@ a hight of 18'), and I do not plan to double drywall, as the 6" exterior studs will be filled with 6" of open cell spray foam insullation. There is no duct work on this level, as it all runs beneath the floor, and is all newly installed as well. The exterior was just stoned last week with 2" thick manufactered stone (see below).



@ lilmike .... it was not my intention to hijack your thread with our specific application of your F20 design. One goes where the responses are

@ everyone ... if my build thread is the more appropriate spot for this dialogue, it may be found here.
beastaudio's Avatar beastaudio 09:46 AM 03-23-2012
I too have read that and it will definitely take a few reads to get right, but that is a great way to do gain structuring. I cant remember but I dont know if he addresses AVR clipping or not, that is still something to be wary of. IIRC the xls-drivecore series amps cant set a highpass low enough for the f-20's, you may need an external EQ to do this. When I was running my f-20's off the xls, I didnt use any of the onboard processing just as nube is suggesting. Let your AVR set the lowpass (80hz is about all you will get out of these, but I managed to squeeze to 100hz after some work with an eq) and for the highpass, a cheap way to do it would be a behringer feedback destroyer, but if you want to go more versatile, the minidsp or Berry dcx2496.
cecaa850's Avatar cecaa850 10:34 AM 03-23-2012
How are you going to keep your drop ceiling from flapping?
beastaudio's Avatar beastaudio 11:08 AM 03-23-2012
Quote:
Originally Posted by cecaa850 View Post

How are you going to keep your drop ceiling from flapping?

haha, yea thats a good question, weight is the best way to keep it from rattling too much.
dutchswan0311's Avatar dutchswan0311 11:08 AM 03-23-2012
Quote:
Originally Posted by cecaa850 View Post

How are you going to keep your drop ceiling from flapping?

I would imagine the same way that any other theater keeps their drop ceilings from "flapping". I don't know what that way is, but every theater I have ever been in has navy blue 2:1 drop ceiling tiles. I have not researched that far yet.
beastaudio's Avatar beastaudio 11:33 AM 03-23-2012
Quote:
Originally Posted by dutchswan0311 View Post

I would imagine the same way that any other theater keeps their drop ceilings from "flapping". I don't know what that way is, but every theater I have ever been in has navy blue 2:1 drop ceiling tiles. I have not researched that far yet.

with the amount of space you are filling you should be fine, I know with my drop ceiling in such a small room, it is hell when I start really pushing my drivers. sounds like the worst trunk rattle, but Ive taken care of most of it thus far
dutchswan0311's Avatar dutchswan0311 12:06 PM 03-23-2012
Quote:
Originally Posted by NicksHitachi View Post

I found this writeup very informative and helpful. It'll take a couple reads for it all to sink in and make sense, or it did me.





What I am getting from this article that NicksHitachi mentions is:

The rated RCA Output of the Pre-Outs on my AVR is 200mV (0.200 Vrms?), which is not enough to drive the XLS1000, which has a sensitivity of 1.4 Vrms?

Forgive me if I am misinterpreting the article...I only read it once
beastaudio's Avatar beastaudio 12:20 PM 03-23-2012
You're close, but see the other box where it says MAX RCA voltage output? that is 3.2 more volts than you will need to run the amp to maximum potential. the Crown only needs AT MOST 1.4volts, anything more, you will clip the inputs of the amp. so basically, you need to find the spot, with your onkyo at reference, to set the sub trim level where it is outputting 1.4volts, no more. Then you will have at least maximized your gain structure until you put new things in the chain...
cecaa850's Avatar cecaa850 12:21 PM 03-23-2012
Looks like it'll put out 4.6V max if I'm reading correctly.
Ricci's Avatar Ricci 12:22 PM 03-23-2012
Quote:
Originally Posted by dutchswan0311 View Post





What I am getting from this article that NicksHitachi mentions is:

The rated RCA Output of the Pre-Outs on my AVR is 200mV (0.200 Vrms?), which is not enough to drive the XLS1000, which has a sensitivity of 1.4 Vrms?

Forgive me if I am misinterpreting the article...I only read it once

The Onkyo has plenty of juice for the Crowns. In your pic it says 4.6v max. This is a common mistake where it is assumed that the RCA output level is the maximum signal strength. It is not.
dutchswan0311's Avatar dutchswan0311 12:25 PM 03-23-2012
Quote:
Originally Posted by beastaudio View Post

You're close, but see the other box where it says MAX RCA voltage output? that is 3.2 more volts than you will need to run the amp to maximum potential. the Crown only needs AT MOST 1.4volts, anything more, you will clip the inputs of the amp. so basically, you need to find the spot, with your onkyo at reference, to set the sub trim level where it is outputting 1.4volts, no more. Then you will have at least maximized your gain structure until you put new things in the chain...

I didn't look at the max because I thought we were only supposed to look at the RMS rating. But I also googled the most expensive AVRs I could find and it seems like 200mV is an industry standard for this class of equipment (or the 4.6V max)...so I was inclined to believe my AVR was fine. Your comment reaffirms that notion. Dumb question: How do I find out the sub trim level at which the 709 is outputting 1.4volts? One more question: So, can I conclude that the clipping on the amps are almost certainly being caused by the AVR and not the 390HFs? I bet this is the process everyone goes through the first time doing something like this...so I apologize to those of you for whom this stuff is old news.
beastaudio's Avatar beastaudio 01:14 PM 03-23-2012
Quote:
Originally Posted by dutchswan0311 View Post

I didn't look at the max because I thought we were only supposed to look at the RMS rating. But I also googled the most expensive AVRs I could find and it seems like 200mV is an industry standard for this class of equipment (or the 4.6V max)...so I was inclined to believe my AVR was fine. Your comment reaffirms that notion. Dumb question: How do I find out the sub trim level at which the 709 is outputting 1.4volts? One more question: So, can I conclude that the clipping on the amps are almost certainly being caused by the AVR and not the 390HFs? I bet this is the process everyone goes through the first time doing something like this...so I apologize to those of you for whom this stuff is old news.

not a problem at all dude. Setting gain structure is the reason why many peoples systems remain with untapped potential.

Do you have a digital multimeter (DMM)? if not, you can find a nice one at lowes for probably 30 bucks. I suggest using one, especially with the extensive system you plan on putting in. Try something like this:

http://www.lowes.com/pd_292758-12704...ter&facetInfo=

So what youll do is, once you have the DMM at the right setting, run some pink noise or a sine wave of some sort through your system at reference with the subs unplugged but the RCA still in the preout of your AVR. On the end of the RCA that plugs into your crown, very carefully touch one of the DMM's leads to the shield of the rca (Round metal part) and the other to the pin of the rca (middle part) and see what your preout is reading. adjust your subwoofer trim level from here to maximize the output at 1.4v. Now you have at least your AVR's sub trim level maximized. From there, anything else you put in the chain will have to be tested similarly.
dutchswan0311's Avatar dutchswan0311 01:48 PM 03-23-2012
Quote:
Originally Posted by beastaudio View Post

not a problem at all dude. Setting gain structure is the reason why many peoples systems remain with untapped potential.

Do you have a digital multimeter (DMM)? if not, you can find a nice one at lowes for probably 30 bucks. I suggest using one, especially with the extensive system you plan on putting in. Try something like this:

http://www.lowes.com/pd_292758-12704...ter&facetInfo=

So what youll do is, once you have the DMM at the right setting, run some pink noise or a sine wave of some sort through your system at reference with the subs unplugged but the RCA still in the preout of your AVR. On the end of the RCA that plugs into your crown, very carefully touch one of the DMM's leads to the shield of the rca (Round metal part) and the other to the pin of the rca (middle part) and see what your preout is reading. adjust your subwoofer trim level from here to maximize the output at 1.4v. Now you have at least your AVR's sub trim level maximized. From there, anything else you put in the chain will have to be tested similarly.

Thanks for the direction. The article referenced earlier had even had images describing this. Question: Will the voltage reading at the end of the RCA cable vary depending on how many speakers are plugged into adjacent RCA Pre-outs? In other words; will it read higher right now since only the subs are plugged in; but then will subsequently split the 4.6Vrms depending on how many drivers are connected?

I think my former question is a little dumb, as I think I read in the article that the sub pre-outs typically get more voltage than the mains or surrounds. I think it also said if one is testing the mains, that one should set the AVR to "Large" in relation to the mains so that it outputs a higher voltage.
beastaudio's Avatar beastaudio 01:54 PM 03-23-2012
Quote:
Originally Posted by dutchswan0311 View Post

Thanks for the direction. The article referenced earlier had even had images describing this. Question: Will the voltage reading at the end of the RCA cable vary depending on how many speakers are plugged into adjacent RCA Pre-outs? In other words; will it read higher right now since only the subs are plugged in; but then will subsequently split the 4.6Vrms depending on how many drivers are connected?

With your AVR, this should not be the case. It could potentially vary slightly, but not significant enough.

I think my former question is a little dumb, as I think I read in the article that the sub pre-outs typically get more voltage than the mains or surrounds. I think it also said if one is testing the mains, that one should set the AVR to "Large" in relation to the mains so that it outputs a higher voltage.

First part is true, second part sounds good in theory, but I have never tested otherwise. as long as no load (speaker) is hooked up when you do the test, you should be ok, otherwise you may fry some voicecoils pretty quick if you are using the wrong freq sine wave
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