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Post by Darren on Jul 27, 2006 8:56:44 GMT -7
Hi Guys,
I'm looking for a little clarity on adjusting the signal properly starting from the receiver and ending at the amp.
Currently I have my AV receiver LFE level at -10, my mains are in the neighborhood of -6 on average. I have my EP2500 set at about 12:00. At these settings the amp is clipping on scenes like Star Wars Attack of the Clones Scene 1 with the ship fly by etc... Also on LOTR FOTR scene 1 ring drop. I would think this amp should be able to be turned up significantly more than 12:00 at these settings before clipping. When it does clip the drivers definately let you know, they fall flat on their face.
4 RL-P 15's bridged mono for 4ohm load
How are you configured? Does my configuration and experience sound normal?
I'm just trying to get an idea if my setup and experience as described above is "typical" .
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Post by ThomasW on Jul 27, 2006 9:52:13 GMT -7
Your drivers are new and not broken in. The suspension on the RL-p's is STIFF. So it takes time for it to loosen up.
It's not surprising to hear that the clip lights come on during those scenes. Seeing the lights flash momentarily is no big deal. The thing to avoid is having them glow continuously.
The level controls adjust the input level, not the output level. So even at 12:00 you can get full output from the amp depending on the drive level of the input signal.
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Post by Darren on Jul 27, 2006 9:57:49 GMT -7
Thanks for the explanation Thomas.
In those scenes the clip lights are bright and solid for more than is acceptable at normal listening levels which is what I'm trying to dial out. I suppose I just need to adjust the level down until those scenes no longer clip badly.
I just thought it was strange that I would have clipping issues with the LFE at -10 and the amp at 12:00... More an observation than a complaint or worry. I must have a very strong signal coming from the receiver. I suppose after the drivers break in a bit the clipping situation will improve?
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Post by ThomasW on Jul 27, 2006 10:03:10 GMT -7
Sounds like something is goofy. What are the indicator lights on the BFD doing?
I've got to run errands so I'll check back later
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Post by Darren on Jul 27, 2006 10:03:47 GMT -7
The BFD is always in the green range.
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Post by jagman on Jul 27, 2006 10:30:31 GMT -7
I've been searching the web and have had a hard time coming up with a reasonable explanation for the follow problem. If setting the level of the output of the integrated amp/receiver only affects the input of the sub amp (and not its output) how do you know what level to have it adjusted? When I change the level of sub output on my integrated amp, it affects the loudness (for lack of a better word) of the sound coming from the IB. And, obviously, so does adjusting the gain on the amp itself. What is the difference between adjusting one or the other, and what approach should be taken so one can figure out which combination is best for his situation?
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Post by Darren on Jul 27, 2006 10:39:46 GMT -7
Jagman, that's exactly what I'm trying to learn as I troubleshoot this apparent configuration issue. My current understanding is the AV receiver LFE level you adjust is basically the strength of the signal...once it gets to the amp the adjustment there is either "throttling back" the signal it gets or "amplifing" the signal. I'd assume the latter since it is called Amp but then again it could be throttling the signal back and amplifying what is left  I might be wrong but that's where I'm at now. I'd like to know if I should be feeding the strongest signal possible to the amp and then dial it back there or dial the amp all the way up and throttle the signal at the AV receiver or a combination of both. |
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Post by Darren on Jul 27, 2006 11:03:17 GMT -7
CORRECTION:
I'm running 4 of those drivers Bridged 8ohm mono...
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Post by jagman on Jul 27, 2006 11:09:50 GMT -7
I had my integrated's output level at 10 and the Samson's gain at about 80%. The IB sounded good, but not great, and the clipping light never lit. Then I set the Samson's gain to 100%... which required me to lower the integrated's output level down to 4.0. While there, the clipping light flickered during LOTR FOTR. I've since adjusted the integrated's output level down to 3.0. Thomas and others have said that a flickering clip light on the Samson is not a problem, but it still makes me worry... I don't like having to hold the remote just in case it stays lit more steadily. What is the risk if the amp clip light stays solidly lit for a second or more? Also... Avalanche owners... have you found your 18" drivers to have stiff suspensions? Mine don't move that much... it may be due them being underpowered. Then again, I have two of them and they are getting 350 clean watts apeice. I would have thought that would have been plenty to get them moving. It's probably a good idea to play the IB loudly for an extended period of time to see if it's movement increases despite the setting staying the same. I have the materials to finish my passive acoustic treatments. All I need to do after that is get a BFD. I have a feeling I'll need to get a more powerful amp. Based on what was written above, I don't think I have enough power in reserve to boost the lower frequencies. If I get a more powerful amp, I can dial in whatever house curve I want  . My impression so far is the Avalanche 18" drivers can handle just about anything thrown at them. |
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Post by Darren on Jul 27, 2006 11:19:19 GMT -7
That's exactly what I'm trying to deal with right now but my clip lights are already staying lit for more than a second on these scenes.
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Post by ThomasW on Jul 27, 2006 12:08:05 GMT -7
Darren,
You might want to understand how a so called volume control works.
Any line-level output on your receiver operates at a max output of 1 or 2 volts (usually). The level control cuts (attenuates) this output when it's set at less than full out. So when you turn up the level it's actually just decreasing the amount of cut (attenuation).
The clip lights indicate an overdriven situation. If you have a bunch of boost dialed in the BFD that can overdrive the power amp since the BFD doesn't have whats called a 'unity gain' setting.
So setting everything is a balancing act between the sub-out, the BFD and the power amp
Where are the input level switches on the back of the BFD set? That might change everything.
It's hard to say if the amp is defective or if you need to rewire the drivers to present a more aggressive load.
I'd be tempted to rewire the speakers to a lower impedance and see what happens.
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Post by Darren on Jul 27, 2006 12:14:03 GMT -7
Thanks for the lesson Thomas, that was one of my thoughts on volume but you confirmed it for me.
I do have about 6 filters and a few of them have max boost in the BFD, I could try and ease off on a few filters and dail back the boost on them. This sound like it might be hitting the mark as it is on certain frequencies that the clip indicators come on strong... at the same volume other effects just as loud don't even flicker.
By re-wiring to a lower impedance do you suggest I go 4 ohm stereo instead of 8ohm mono?
Oh, for the record this is the same behavior I saw with the EP1500 so I don't think it would be a defect in the amp.
Thanks again for the help.
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Post by ThomasW on Jul 27, 2006 12:23:37 GMT -7
By re-wiring to a lower impedance do you suggest I go 4 ohm stereo instead of 8ohm mono? Yes whatever configuration increases the output power |
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Post by Darren on Jul 27, 2006 12:24:54 GMT -7
Actually I'm at max power I can get from the amp without using only one of the voice coils from each driver.
8ohm bridged mono = 375 watts per driver
4ohm stereo = 325 watts per driver
I could go 2 ohm stereo for 600 watts per driver, the amp says it will do it and it provides the specs but shouldn't I be scared to do that?
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Post by chrisbee on Jul 27, 2006 12:33:42 GMT -7
Interesting discussion. It's nice to compare notes like this.
I had the opposite problem of not getting enough signal from my stereo preamp for my EP2500 to light the signal LEDs.
I have been in discussion with a PA engineer who was most helpful.
Aparrently bridging is exactly the same as dual mono into half the impedance per channel.
So 4 Ohms bridged is the same as 2 Ohms per channel dual mono. My engineer contact suggested that 2 Ohms per channel should always be avoided in the interests of longevity of the power amp. On the EP2500 this seriously increases amplifier distortion (x10) and reduces damping factor (x4).
So after trying 4 Ohms bridged for a while I have returned to dual mono series pairs for 8 Ohms per channel. On his advice I have increased the input gain by 6dB on my active crossover. This did far more for serious output from my IB than using bridged mode. The EP2500 never had enough signal to get really going until now.
I'm still getting only a few mm of cone movement but the bass is now seriously overpowering which finally gives me some control over comparitive levels from the IB relative to the speakers.
My BFD is still showing the first signal bars only rarely. On heavy organ bass the first bars may light up steadily for the duration of a single note when levels are well above a steady 85-90dB. The second bar on the BFD is still as rare as hen's teeth.
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Post by Darren on Jul 27, 2006 12:43:41 GMT -7
This is good comparison.
My BFD sees nearly all the green bars regularly on largely dynamic scenes but usually lights up 3 or 4 when there is good LFE present.
I could try 4 ohm dual mono but that would probably be the same as 8ohms bridged which is what I'm running now. I'll increase my LFE signal from the receiver to see if that helps out too in the new configuration as I adjust the filters down.
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Post by jman on Jul 27, 2006 12:58:58 GMT -7
I had my integrated's output level at 10 and the Samson's gain at about 80%. The IB sounded good, but not great, and the clipping light never lit. Then I set the Samson's gain to 100%... which required me to lower the integrated's output level down to 4.0. While there, the clipping light flickered during LOTR FOTR. I've since adjusted the integrated's output level down to 3.0. Thomas and others have said that a flickering clip light on the Samson is not a problem, but it still makes me worry... I don't like having to hold the remote just in case it stays lit more steadily. What is the risk if the amp clip light stays solidly lit for a second or more? Also... Avalanche owners... have you found your 18" drivers to have stiff suspensions? Mine don't move that much... it may be due them being underpowered. Then again, I have two of them and they are getting 350 clean watts apeice. I would have thought that would have been plenty to get them moving. It's probably a good idea to play the IB loudly for an extended period of time to see if it's movement increases despite the setting staying the same. I have the materials to finish my passive acoustic treatments. All I need to do after that is get a BFD. I have a feeling I'll need to get a more powerful amp. Based on what was written above, I don't think I have enough power in reserve to boost the lower frequencies. If I get a more powerful amp, I can dial in whatever house curve I want . My impression so far is the Avalanche 18" drivers can handle just about anything thrown at them. This isn't exactly what you want to know but right now I'm using 2 Ava 18's in dipole cabinets with a Samson S1000. Each driver is running 4 ohms (series VC) so they get 500 watts each. I have the gain knobs set to max and my BFD only flashes yellow at reference level using the intro for Toy Story 2. All that said, I've yet to see the 3rd light on the Samson flash and the drivers are reaching audible distress at just the 2nd light flashing depending on the source content. They are definitely using their full xmax at this point and seem plenty "loose". |
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Post by nolook on Jul 27, 2006 13:02:40 GMT -7
Darren... Why 4 ohm mono ? Why not 4 ohm stereo.. I'm running to Av 18's via an old ProLogic amp, (rated) 120 amps per side, and getting impressive results..
Thomas, is there an advantage or disadvantage to running mono or stereo ? Or is it just that having that ability allows for more hook up options ?
Jagman.. No problems with cone movement what so ever.. Not from day one.. And it's playing quite loud !
I watched WOTW last night, and my son came back from helping the neighbor doing some interior painting letting me know they were both confused by the sound of thunder ? "It didn't look like rain earlier ?" Too funny..
My backwave is dumped into our 2 car garage, and the painting was going on inside a home across an alley from ours.. I can't WAIT to get pro amp ! !
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Post by Darren on Jul 27, 2006 13:06:12 GMT -7
Dual mono or stereo are the same thing... I'd just feeding the same signal to either channel which is actually a dual mono signal if you get technical about it. The amp would be running in stereo.
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Post by chrisbee on Jul 27, 2006 13:14:05 GMT -7
Just to be absolutely clear not all amps allow bridged mono mode. (which is the mono that Darren is using)
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