Moderators Youthman Posted October 11, 2007 Moderators Share Posted October 11, 2007 I have a Velodyne F1500 (15" sub with 250 watt amp). During loud explosions, the sub will occassionally pop. I'm assuming that this is due to over-excursion of the sub. I am using an HK AVR55 dolby digital receiver. The sub is turned up to 3 (out of 10) on the back and is set at 0dB on the receiver. The receiver volume is set at 50dB. The sub does not continually pop, just when there is a big bang (ex first tap of the fish tank in Nemo). Is this an indication that the sub is blown? It sounds great until it is driven too hard. My thought is why is it popping when it is turned down so low (unless it is blown)? I could understand if I had the sub level at 15dB and at 3/4 to max on the back of the sub. If it is blown, any ideas where I can get a used F1500 sub at (not the enclosure or the amp, just the woofer). Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted October 11, 2007 Share Posted October 11, 2007 sounds like your amp is clipping Quote Link to comment Share on other sites More sharing options...
wuzzzer Posted October 11, 2007 Share Posted October 11, 2007 I don't know if it will help, but you can give it a try: Its always been recommended to me to turn the gain on the sub all the way up and then adjust the sub's level with your receiver's sub output setting. If that doesn't work, there are plenty of subs out there with amps bigger than 250 watts. Quote Link to comment Share on other sites More sharing options...
Moderators Youthman Posted October 11, 2007 Author Moderators Share Posted October 11, 2007 There might be some amp issues. If I turn off the DVD player and adjust the volume knob on the back of the sub, the sub will sometimes push out. No sound, just movement. This is with no audio source being fed to it. I found it on Craigslist. She was selling 3 klipsch speakers and a velodyne sub. I made her an offer of $250 for the sub if I liked it and it was in good condition. I originally went to look at just the sub. I wasn't really impressed with the amount of bass that it produced (especially for a 15" sub) but she did have a huge living room with 15 feet ceilings. I went home without buying it. I emailed her two weeks later to see if she had sold her speakers and said if she wanted to get rid of them cheap, I might be interested. She emailed me back saying, "Make an offer". I offered $200 for all four speakers. She countered with $300 and I asked her if she would meet me in the middle and she agreed to $250. As mentioned in a previous topic, this is a temporary setup. The Klipsch speakers sound great and are definitely worth the 250 themselves so I do not feel that I got ripped off. The sub sounds good at decent volumes. It is over a 10 year old sub so it is likely that it is gone bad...just not sure what needs fixing/replacing. Quote Link to comment Share on other sites More sharing options...
mas Posted October 11, 2007 Share Posted October 11, 2007 I have a Velodyne F1500 (15" sub with 250 watt amp). During loud explosions, the sub will occassionally pop. I'm assuming that this is due to over-excursion of the sub. I am using an HK AVR55 dolby digital receiver. The sub is turned up to 3 (out of 10) on the back and is set at 0dB on the receiver. The receiver volume is set at 50dB. The sub does not continually pop, just when there is a big bang (ex first tap of the fish tank in Nemo). Is this an indication that the sub is blown? It sounds great until it is driven too hard. My thought is why is it popping when it is turned down so low (unless it is blown)? I could understand if I had the sub level at 15dB and at 3/4 to max on the back of the sub. If it is blown, any ideas where I can get a used F1500 sub at (not the enclosure or the amp, just the woofer). The F1500 sub is a modest sub that is not intended for no-holds barred input, nor is it a servo unit. That being said, it sounds like it may be working fine. The potential to 'bottom out'/reach its excursion limits on extreme impulse FX is not surprising. There are few subs where this cannot be achieved if they are turned up sufficiently. This combined with insufficient headroom in the amp (it is only a 250W amp!) for such loads is a situation just waiting for such an occurance. Now, this does not preclude there being a problem, but the scenario described sounds like a classic case of encountering a stimulus, that, combined with the other settings, etc., simply exceeds the unit's capacity. Quote Link to comment Share on other sites More sharing options...
DrWho Posted October 12, 2007 Share Posted October 12, 2007 Sounds like a bad amp to me. A bottoming out driver is going to create a clack or fart sound, but never a pop. I would wager that it's a bad power supply cap or possibly a bad gate driver on the output mosfets. I'm trying to think of other things that can create this problem... When the subwoofer pushes out as you describe, is it audible? Or is it just like the driver is moving forward? A blown opamp at the input of the sub can create DC offsets which can behave like you describe too. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted October 13, 2007 Share Posted October 13, 2007 A pop or clack sound can be one of two conditions in my mind. One is the voice coil former striking the pole piece upon re-entry into the magnetic gap. The other is the spider stretching tight. Quote Link to comment Share on other sites More sharing options...
Moderators Youthman Posted October 13, 2007 Author Moderators Share Posted October 13, 2007 I have had several people suggest the voice coil. Does that mean I just need to replace the driver? Quote Link to comment Share on other sites More sharing options...
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