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Post by nolook on Jul 27, 2006 13:29:06 GMT -7
Regarding the stereo / mono / bridged issue.. I understand the options don't all exist on all amps, my question to Thomas, or anyone else who may have some insight on this, was to the advantages or disadvantages of each.. Such as, input or output sensitivity, signal to noise ratio, any distortion problems, etc.. Seems life is full of compromises, wondered if may be looking at one ?
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Post by Darren on Jul 27, 2006 13:34:35 GMT -7
I may be wrong but I believe 4 ohms bridged has more noise and is harder on the amp than 4 ohms dual mono.
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Post by ThomasW on Jul 27, 2006 13:42:29 GMT -7
Darren,
Try using all the VC's.
Wire each driver's VC's in series = 2 ohm,
then parallel the drivers in pairs = 4 ohm.
Run the amp in stereo/dual mono, so one 4 ohm pair/channel.
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Post by Darren on Jul 27, 2006 13:49:24 GMT -7
I'll do that when I get home tonight.
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Post by chrisbee on Jul 27, 2006 13:52:30 GMT -7
Darren, Wire each driver's VC's in series = 2 ohm . I think you mean 8 Ohm in series, Thomas. Not 2 Ohms.
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Post by jagman on Jul 27, 2006 13:56:03 GMT -7
jman... you are lucky you chose the S1000. I was worried the S700 would be too much power. Before I decided on the S700, I actually considered the Behringer A500. I would have really been up the creek had I done that.
If Nolook is getting that much movement with 120 watts from a prologic receiver, something must be wrong in my setup. When I installed the sub, I quadruple checked my wiring, and just the other day I pulled the wires from the amp and rechecked polarity with the 9 vold battery test. I also checked to see if they were in phase with the front speakers. They are in phase with each other and with the mains. The speaker cables going to the IB are 12 gauge and only about 18' long, so that should be plenty sufficient. The only other thing I can think of is the 3' DIY RCA/XLR cable between the integrated and the S700 may be of poor quality (or my craftmanship may vacuum). It has come apart several times (the XLR end is "solderless"). I'm using a microphone cable and the strands within it are very wimpy. That very well may be contributing to the problem. Hmm.
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Post by ThomasW on Jul 27, 2006 14:06:04 GMT -7
I think you mean 8 Ohm in series, Thomas. Not 2 Ohms. Oops my fingers are faster than my brain.... Anyway series the individual VC's for an 8 ohm load, then parallel 2 drivers for a final 4ohm load
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Post by jagman on Jul 27, 2006 14:59:35 GMT -7
I just talked to Chad at AA and he said the Avalanches can handle up to 700 watt each in an IB .
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carl
Junior Member
Posts: 95
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Post by carl on Jul 27, 2006 15:18:53 GMT -7
Darren, permit me at least 1 stupid question. Are you seeing the clip lights or the signal lights coming on? I thought I was clipping my 2500 and realized I was seeing the signal light illuminate. Secondly, Thomas had recommended running the amp at full gain and adjusting my lfe level with my receiver. Works great. I also read a question about the Avalanche 18's movement (or lack of). Normally you don't see a lot, but if you want to watch them dance, put on a 10Hz test tone and crank it up. You'll see the excursion they're capable of. The 4 of mine will make the ceiling fans turn in adjacent rooms. They PUMP.
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Post by Darren on Jul 27, 2006 16:01:59 GMT -7
Hi Carl, No stupid questions here It is indeed the red clip indicator and not the orange signal lights. I just finished wiring 4 ohm dual mono. I'm gonna play around with the LFE level and gain levels...
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Post by Darren on Jul 27, 2006 16:21:03 GMT -7
Ok, just switched the amp to 4 ohm dual mono and that seems to have helped a little.
The amp is clipping on the ring drop scene at the end where the beast blows up in a sweeping tone. At the point where it clips badly I'm hitting 112db in the listening position using the old analog radio shack meter uncorrected.
I have one filter that is +12db at 65Hz... I'm wondering if that is what is clipping the amp. I get flicker on the ring drop now but no solid red. I'm assuming that's because of the slightly less output at 4ohm dual mono and a little less strain on the amp.
Now, I need to fiddle with the LFE and gain.
Recommendations? Amp all the way up and LFE down? Not sure if there is enough room for that. I have the BFD at +4 and it doesn't clip at all.
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ken
Full Member
Posts: 187
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Post by ken on Jul 27, 2006 16:21:24 GMT -7
I just talked to Chad at AA and he said the Avalanches can handle up to 700 watt each in an IB . Thats odd.....when l bought my 18's off him last year l was told he had ran them bare without an enclosure and was getting to xmax at around 250w.......l'm yet to set mine up so l cant comment whether that is right or not, but that was what he reckoned back then would be the required power to do it in an ib....go figure
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Post by ThomasW on Jul 27, 2006 16:28:14 GMT -7
I just talked to Chad at AA and he said the Avalanches can handle up to 700 watt each in an IB . Nope no way......
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Post by jagman on Jul 27, 2006 17:41:38 GMT -7
He said in free air about 250 watts would push them to their limit, but in an IB they handle much more power. I can see how that may happen in a 4 x VAS IB but I'm a little skeptical of 700 watts per driver in a 10 x VAS IB. I'm not saying he's wrong... but that is a lot more power per driver than what is typcially recommended. I would say 500 watts sounds about right... especially with jmans experience with an open baffle. Chad said the drivers in an IB, as opposed to an open baffle, have proven over the last year to eat up a lot more power than he initially thought. In fact, he said he hasn't heard of any Avalanches in a home IB bottoming out. The only ones he knows of in any application that have bottomed out were a pair in a car with 2000 watts apeice . Crazy car people .
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Post by ThomasW on Jul 27, 2006 18:18:11 GMT -7
He said in free air about 250 watts would do it, but in an IB they handle much more power. I can see how that may happen in a 4 x VAS IB but I'm a little skeptical of 700 watts per driver in a 10 x VAS IB. He said the drivers in an IB have proven over the last year to eat up a lot more power than he initially thought A big IB is the same as free-air. So I don't see how the power rating could basically triple from open-air.
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Post by jagman on Jul 27, 2006 18:27:16 GMT -7
I agree... 700 watts/driver does seem quite high, but I don't think he'd say that if it wasn't true. From my experience 500 watts seems right. Jman said 500 watts gets his moving to their limits in free air, and 350 watts definitely doesn't do it for mine.
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ryans
Full Member
Posts: 132
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Post by ryans on Jul 27, 2006 19:17:11 GMT -7
Very likely. What's the bandwidth setting on that filter? If its wider than about 30/60 then you're probably boosting most of your signal and then calibrating down to compensate for it. If its narrower than that then you're probably calibrating to the unboosted level. In that case you're just asking for the amp to clip. At +12dB, the peak frequency will ask for 16 times as much power as is used outside of the boost band. So imagine you're listening at a level that "only" requires 50 watts for most frequencies. Then a 65Hz note comes along at the same level and requires 800 watts If you have to boost a narrow frequency by 12dB then you're probably trying to battle a null. Pumping more power into an acoustical black hole is a losing battle. And in another listening position, the null will be shifted to a different frequency - then you'll have a null plus a 12dB peak. Better to treat the room. Is the 12dB boost very near to some cut filters? Maybe you should post all your filter settings.
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Post by Darren on Jul 27, 2006 19:44:03 GMT -7
Good info. Here are my filters:
25Hz 20/60 -4 32Hz 6/60 -7 50Hz 10/60 +7 63Hz 4/60 +12 80Hz 21/60 -10 100Hz 13/60 -12
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Post by Darren on Jul 28, 2006 7:02:22 GMT -7
So, because of the boost to compensate for a null between 50 and 65 Hz I'm considering a few possibilities to correct in a more appropriate way since room treatment isn't in my future.
1. Adjust my boost down to +5 which will leave me with a bit of a null and correct the huge hump I get in other areas of the room.
2. Adjust my crossover to 60Hz which will direct most of the null to my mains which go down to 55Hz then drop off rapidly. This will create a hole in my response though.
3. We are getting new additional furniture for the room and eliminating a big shelving system on the right hand wall. Adding a couch to that wall and removing that large flat surface might have some beneficial effects no?
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Post by eeyore on Jul 28, 2006 10:36:09 GMT -7
why the cut at 100hz?
is it related to your house curve or is your crossover set at 120hz?
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