Amp clipping or Speaker bottoming out

Discussion in 'Archived Threads 2001-2004' started by Yogi, Oct 19, 2002.

  1. Yogi

    Yogi Screenwriter

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    Last night I was watching Monsters and in the scene (forget the chapter number) where the child decontamination agency (CDA) puts the childs sock in the little dome to incinerate it with that explosion, it sounds like a muffled explosion and my speakers sounded like they clipped. I removed the grill and replayed the scene and saw the bass drivers really move like I have never seen them before. BTW I was watching at refrence level so it was loud but what surprised me like a loud pop at the peak of that explosion. Now was it my amp clipping? or was it the speaker bottoming out? I dont know. I have never heard my amps clip or my speakers bottom out. My Proceed amp is rated at [email protected] and double at 4 so its highly unlikely that it might clip.

    It is worrying me that could it be something wrong with the amp that made it clip or was it the speaker bottoming out. The speaker is rated to take upto 175W peak so there shouldn't be a reason for it to bottom out. Everything is pointing to the amp. But I just cant imagine the Proceed clipping (which is supposed to be stable into 2 ohms). So my question is what does clipping sound like? Does it sound like a pop or like something else. BTW I had turned off the sub and was rerouting the LFE to the mains during this movie as I like the taut bass that my Proceed gives through the mains rather than the bass from my Velodyne even though the quantity of bass is less.
     
  2. Michael R Price

    Michael R Price Screenwriter

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    Sounds like clipping, or your driving your speakers seriously into distortion. The woofers on my speakers will distort more and more given higher power input and almost never bottom out since the physical limits of the suspension cannot be reached.

    If you play that scene over and over and slowly increase the volume, does this muffled sound increase slowly or does it begin occuring abruptly at a certain volume?

    Bottoming out would sound like a violent thwacking.
     
  3. Kevin. W

    Kevin. W Screenwriter

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  4. Yogi

    Yogi Screenwriter

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    It happens only beyond a certain volume. When it happens it sounds like a loud pop and it doesn't happen when the LFE is routed to the Sub and the speakers are still left at large. With the LFE routed to sub the bass drivers dont move half as much as when I have the LFE routed to the mains. Without the sub the woofers just move like they are about to jump off the cabinet. Its scary to even look at it.
    Why would an amp like Proceed run out of juice on just reference levels? Reviews of the amps claim it could drive any kind of low impedance speakers, ESLs and is stable down to 2 ohms and that its much more powerful than its rated power...yada..yada..yada. Do you guys really think that its running out of juice? Or could there be something wrong with the amp thats causing it to clip? Please advice[​IMG]
     
  5. Patrick TX

    Patrick TX Stunt Coordinator

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    I recently had a pair of Klipsch RP5's connected to a Yamaha RX-V1 watching the same movie, same scene. SAME RESULT. Get this, I had the speakers set to small. Each Klipsch had a 12" powered woofer. One of the subs was bottoming out with the volume on the sub at ONLY 9 O'clock! This movie has INSANE levels of LFE! I had to dial the sub all the way down to stop the popping. It also popped on music with heavy beats, namely Limp Bizkit track 1 from Chocolate Starfish. It was popping at 1/4 volume on the Yamaha, sub set at 9 O'clock. Needless to say, the speakers were JUNK. Only 1 was doing this, luckily I was in the 13th day of a 14 day return period. My SVS PC+ that shipped yesterday better not pop!
     
  6. Yogi

    Yogi Screenwriter

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    Thanks Patrick for sharing your findings. My Velo sub doesnt bottom out but with the LFE routed to the mains it seems like it bottoms out (or the amp clips). How did you conclude that it was your speakers bottoming out and not your amp clipping? Since I have no experience with clipping or bottoming out drivers, I am curious.
     
  7. Patrick TX

    Patrick TX Stunt Coordinator

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    I barely had the volume knob cranked on the Yamaha. It was most certainly the woofer, sounded like 2 wood blocks being smacked together. I replayed it over again, putting my ear to each component. It was clearly the right main woofer. UGLY sound. If you value your mains, I would route the LFE to the sub during 5.1 playback of certain "known offender" DVD's. Monsters Inc has bottomed MANY a powered sub already! Do a search on the title.
     
  8. Yogi

    Yogi Screenwriter

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    Thanks Patrick. Thats what I am going to do from now on that is re route the LFE to the SUB. I dont use the SUB for music and since I listen to music mainly I keep the sub off the picture sometimes so that I have nice taut bass even though they dont shake the house. Well I guess I'll not be doing that often.

    Thanks again.
     
  9. Rob Rodier

    Rob Rodier Supporting Actor

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    Sounds like this thread is almost finished but here is my 2c anyway.

    Sounds like the speaker bottomed out to me. I ran 83 db sensative speakers temporarily with a 100wpc adcom amp, and those little instanteneous distortion leds light up a lot before I learned what level to keep things at. Clipping sounds ugly, a woofer bottoming out sounds REAL ugly. Like you described. A 2ch proceed amp is not going to run out of juice on a quick impact, explosion, or whatever. Not even the older "AMP" models to which yours is superior. My experience anyway.

    Anything is possible, but I put my money on the speakers.

    -rob
     
  10. Mike Ilano

    Mike Ilano Extra

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    This happened to me too running an SVS 1646cs/NAD 2700 THX amp at reference level! I had to back off on my Rotel 1066 sub level settings for Dolby Digital.I heard a "pop" and thought I permanently damaged the woofer,luckily there's still bass comin' out still...WHEW!
     
  11. Yogi

    Yogi Screenwriter

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    luckily for me too there is still bass comming out of the speakers. No more running LFE thru my mains, on movies. In music I still will be running the LFE through mains untill they start comming out with music with sub 20 Hz transients. I hope they don't.
     

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