How to prevent Clipping

[epicentyr]

I have a LLT Sono with a Fi-Q18 d2 running of an EP2500. I am having trouble with the amp clipping on high power scenes. I have the signal at -5.5dB on my Onkyo 805. Am I expecting too much from this setup or is there a way to stop the amp from clipping. My room is 14' wide and 25' long I expect a sub that takes up a good portion of the room to shake the house before the amp clips.

[Otto]

How do you have the system wired, and how do you have the amp configured?

[epicentyr]

the amp is wired in bridged mono and fed from the preamp sub out on my 805. sorry for such a long delay between posts.

[imbeaujp]

When you are listening to Dolby Digital Movies you can lower the dynamic level. But you can not do that with DTS I think...

Otherwhise, if you could use the limiter fonction built in the Behringher UltraDrive Pro . It seems to be a verry nice product for that.

Or maybe you ask too much from your system...

Hope this could help.

JP

[ccdoggy]

that sub should shake the house pretty good. I have a 15" Q LLT and the entire house feels it when i do tests.

I would take a look and make sure the dip switches on the amp are setup correctly.

[Blueeyedfrog]

Maybe you could try lowering the output from the receiver? If you have a Behringer feedback destroyer you can set the output from your receiver by using the clip meter. I have a NAD receiver which outputs 50watts RMS on each channel similtaneously. I have to set the sub output to -10 (scale ranges from -12 to +12) while the rest of the speakers are around 0 - +1. Otherwise the amp clips at higher volumes (e.g. WOTWs). My sub amp gain is set around 45%. I don't know why, but if I try to up the gain on either the receiver or sub amp, I get clipping.

Hope this helps...

[epicentyr]

I think that I may be loosing a lot of room gain because my room is shaped like an L and the sub is in the center of the long back wall and the screen is at the end of the long side. ??? ha a picture is worth a thousand words. I am probably going to go with either 4-12" subs or 2-15" because the enclosure for the 18 is just too massive for good placement in the theater. I will also try turning the signal from my receiver down farther and turning the gain on the EP2500 higher. I always thought that it was best to do less amplification on a strong signal than to amplify the heck out of a weak signal. Does this not lead to distortion?

[Blueeyedfrog]

I too have an L-shaped room. You'll get much more gain if you put the sub in a corner (if possible). However, I read a paper a while back that demonstrated that the bottom left corner of the L shape, which is where most people assume will be the best position, is not the best position. In fact, any of the other corners is usually better (due to room nodes etc.). I found I got the flattest response placing the sub in the top right corner of the L (my screen is at the bottom leftish).

I tried turning down the receiver gain and turning up the sub amp gain but found I could only bump it up about 10% from memory.

What's your room made out of - concrete? If so, you should have high gain but less tactile sensation than from wooden floor boards. I fitted some el cheapo 25watt RMS bass shakers to the listening chairs - actually really good! They really complement the sub. I had a stereo amp lying around and so it was cheaper and easier than constructing a wooden stage the get the vibrations from the sub to the chairs. But definitely try the sub in a corner - it makes a big difference.

[thxgoon]

epicentyr wrote:

I have a LLT Sono with a Fi-Q18 d2 running of an EP2500.

Forgive me if this is obvious but how do you have the amp wired to the woofer? Do you have dual coils? What impedance are they and how are they wired together before you hook up the amp?