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Post by mirageman on Feb 1, 2016 7:06:42 GMT -7
So I'm considering purchasing a new Pro amp to power my IB and sealed Tempest subs. I'm thinking about using one channel for the IB and the other for the sealed Tempest. I've been looking at the new Crown XLS series 2 amps. However I now these days the wattage ratings are usually a bit inflated for marketing purposes. Is there any way to decipher what the real world output is on these amps so as to make a better decision on which model to pick?
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Post by ThomasW on Feb 1, 2016 11:14:24 GMT -7
There are numerous ways to test amplifier power continuous, peak, instantaneous, etc.
Mgfrs typically chose the one they think best represents their product.
Audio (music or movie sound track), never use a continuous fixed amount of power. And larger amps, those with ratings above the fixed limits imposed by the breaker (say 1.5k watts) are banking on a crest factor, most often 6:1 sometimes higher.
The FTC sets standards when it comes to "home audio" power amps. Those standards don't necessarily equate to Pro Sound power amp ratings.
In addition we use a 'derated' max power when it comes to drivers mounted a IB subs. For example 325-350 watts max per Fi IB3.
I don't recall numbers for a port mounted Tempest. When you have that number use it and the numbers for the Fi to determine the power required for your sub.
Thing these days output power is relatively cheap, so IMO it's better to buy an amp with a higher power rating compared to one that will just sneak through with the bare minimum,
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Post by mirageman on Feb 1, 2016 12:55:31 GMT -7
Thanks Thomas. If you remember I'm running 2 pe ib 15's which you said only need 170 each. The sealed tempest specs a pmax of 750 watts rms.
I'm thinking an amp that does around 500 watts per channel into 4 ohms would work. What do you think?
Both the pe 15's on one channel at 4 ohms and the tempest run @ 4 ohms on the other.
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Post by ThomasW on Feb 1, 2016 14:07:42 GMT -7
When project questions are posted in a new thread as opposed to the actual project thread, it's problematic for me to remember the specifics of the build. Hence my statement about the Fi drivers as opposed to your PE units.
A pro sound amp rated at 500 watts/channel would be the smallest one I'd consider. It's better to error on the side of having more power than necessary as opposed to just enough. Too small an amp runs the risk of clipping which IMO is more dangerous than having an amp with too much power that always be turned down.
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Post by mirageman on Feb 1, 2016 14:11:53 GMT -7
Sorry, just thought posting in the amplifier section would possibly help others finding themselves contemplating the same things as I.
I really appreciate the guidance on these matters.
I now know what to look for.
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Post by mirageman on Feb 3, 2016 15:53:29 GMT -7
Just scored this at a pawn shop. Hopefully it will fit the bill.
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Post by ThomasW on Feb 4, 2016 6:56:41 GMT -7
It's not exactly a powerhouse, fingers crossed it does want you need....
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Post by mirageman on Feb 4, 2016 9:48:52 GMT -7
It's not exactly a powerhouse, fingers crossed it does want you need.... Thomas, I'm a bit confused. You said that the IB drivers only needed 170 watts each to reach full excursion right? 500 watts into 4 ohms will give more than that to a pair of them. And 500 watts into the 4 ohm load of the tempest should be plenty I would think as well. Why do you not think it would be enough? They have two more of these amps that I could buy. I could always bridge two of them one for the IB and one for the tempest but then that would be well over a thousand watts each.
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Post by ThomasW on Feb 4, 2016 11:35:27 GMT -7
Try it out, it will probably be just fine.
If it turn out you need more uumph buy another.
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Post by mirageman on Feb 4, 2016 12:06:08 GMT -7
Try it out, it will probably be just fine. If it turn out you need more uumph buy another. I guess I just wondered why you thought it might not be enough? I understand headroom is a good thing. Just didn't know if there's something I'm missing?
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Post by ThomasW on Feb 4, 2016 18:06:17 GMT -7
I posted that I thought 500 watts was the minimum power, and that it was better to have more power than just enough for reasons of potential clipping.
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Post by mirageman on Feb 5, 2016 8:06:59 GMT -7
Gotcha. So what about level matching to the rest of the system? What I mean is if the subs have an enormous amp powering them and the rest of the system has say 150-200 watts per channel (Obviously it depends on the efficiency of the speakers) you only have so much control via the pre/pro to adjust levels. Is it possible to feed the subs too much and overpower the output of the rest of the system? At this point I am just talking theoretically because I have not had a chance to hook up the new amp or even to add the sealed sub to the system. I just finished installing and painting the trim in the room. I hope to be able to put everything back together soon and start experimenting. I fell a little bit of a sense of urgency to go pick up another of those amps for fear they might get sold. Heck I might just buy them both and use the three to power my L,C,R and surrounds and look for another amp all together for the subs . But I digress...
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Post by ThomasW on Feb 5, 2016 9:05:04 GMT -7
The amp has output control knobs on the front panel. Those plus the control level provided by the pre/pro is all you'll need
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Post by mirageman on Feb 11, 2016 6:05:35 GMT -7
Alright, so I went ahead and bought the other two amps (now have 3 ). That said I'm pretty sure that I will be OK using one channel for the IB and one for the sealed Tempest. The other two amps will be used for L+C+R duty. My next question relates to signal level matching. I bought a MiniDSP 2x4 (unbalanced) awhile back before I decided to go the pro amp route. I am now concerned that the max signal level from the Minidsp of only .9V will not be hot enough to drive the amp to full power. QSC states it need 1.1V reach full power @4ohms and 1.2V @ 8ohms. Minidsp does off a "balanced" version that can output up to 4V depending on configuration and as far as I can tell will actually convert an unbalanced signal to balanced. Would it be a wise idea to perhaps use the balanced version instead in this case? Or possibly use something like the Cleanbox Pro after the MiniDSP ?
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Post by ThomasW on Feb 11, 2016 7:52:57 GMT -7
I don't understand the anticipation/speculation about possible issues when the equipment is at hand for an actual test.
Hook up the MiniDSP to see if it does what you want. If it does you're good to go, if not then look for solutions.
If these questions are based on the fact that you want the balanced unit by all means buy it. Then buy XLR connectors and a length of bulk microphone cable so you can make your own custom balanced cables. These are cheap to make and running a fully balanced system drastically cuts down on system 'noise' or the potential for noise
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Post by mirageman on Feb 12, 2016 7:07:57 GMT -7
I don't understand the anticipation/speculation about possible issues when the equipment is at hand for an actual test. Hook up the MiniDSP to see if it does what you want. If it does you're good to go, if not then look for solutions. If these questions are based on the fact that you want the balanced unit by all means buy it. Then buy XLR connectors and a length of bulk microphone cable so you can make your own custom balanced cables. These are cheap to make and running a fully balanced system drastically cuts down on system 'noise' or the potential for noise Wayne I think my OCD is rearing it's ugly head . To make me look even more crazy I had to return the QSC amps yesterday. One of them had issues when turning on where the clipping lights stayed lit and would not produce any output. Turned out that there was a pretty badly burned area around some resistors on the main PCB. I opened up the other two amps and both had the same thing just not exhibiting the symptoms yet. The pictures below are of the best looking of the 3 amps. I did a search and found a service bulletin regarding this exact issue put out by QSC many years ago. I spoke with a tech and he recommended replacing the main boards to the tune of $500 each! It just didn't make sense for me so I returned them thankfully for a full refund. So now it's back to the drawing board in search of another amp. I'm back looking at the inukes along with the EP series and QSC RMX series amps. I'm leaning toward the inukes at the moment due to possibly eliminating the minidsp from the signal chain. Do inukes allow independent eq'ing of the two channels?
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Post by mirageman on Feb 12, 2016 14:09:09 GMT -7
Pretty sure I'm gonna go the inuke route. The only question that remains is the 3000 or 6000 version? Or maybe 2 1000's to use bridged?
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Post by mirageman on Feb 15, 2016 7:24:00 GMT -7
Pulled the trigger on an NU3000DSP. Hopefully that will be enough.
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Post by ThomasW on Feb 16, 2016 8:13:48 GMT -7
Should be just fine
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Post by mirageman on Feb 16, 2016 10:43:47 GMT -7
Yeah, i finally got around to modelling the subs in WinISD. I should have done that before I started the build as i t would have helped to determine driver selection easier based on desired DB output but now I know better. This whole process has been a learning experience and eye opener to say the least. Both the dual driver IB and the sealed Tempest will reach xmax in the lower freqs with around 400 watts. Worst case I can always use it bridged for one or the other sub and get another amp to do the same . They're cheap enough that it won't break the bank to do so. BTW I played with the Behringer software last night and it is very easy to use and seems like it should offer more than enough flexibility to dial in the subs. Can't wait to get the opportunity to start playing with my Umik-1 and REW. That'll be a whole other learning curve I'm sure.
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