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Matching speaker ratings to amp power

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gen0me View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gen0me Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2017 at 6:26am
Than its closer to like unmastered in total. Though vocal itself is not at all power hungry. But you have to go few db with music to "master" it to vocal. That is overcomplicated. In studio vocal would be leveled and compressed seperatly. Seperatly some groups of drums synths etc and than everything will be compressed after mixing. So here you cant go reverse cause everything was already compressed without vocal.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jngggggggg Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2017 at 1:43pm
So only rms? Or....
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gen0me View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gen0me Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2017 at 2:16pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mini-mad Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2017 at 5:43pm
Dynamics is your one word answer.

If it sounds like a gorilla is trying to escape, turn it down.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jammin75 Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2017 at 6:04pm
u need headroom Big smile
feel the vibes !!!   "Who Feels it Knows it"            Strong like Lion              
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jngggggggg Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2017 at 6:29pm
I guess the question is how much headroom if it's not "match program" sorry I just want to take the guesswork out completely

Edited by jngggggggg - 15 August 2017 at 6:29pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Hemisphere Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2017 at 6:40pm
As much as you can afford so long as you carefully manage the peak and RMS with a limiter. 

Of course if you're playing heavily compressed music all night, you're certainly not going to want to let so much amp power near your rig, but consider this:

You have a live band playing through your system to a packed room. You've carefully specified a system which is an appropriate size, and most of the event you're playing pretty much as loud as it's sensible to run the system, and the crowd is loving it.

Because it's live uncompressed music you can be confident enough that you're not risking destroying your drivers if you turn it up another 4 or 5dB for the high energy finale, and if it pisses off the dB patrol, who cares? It was only one song and you'll get away with it. Probably. So you want the headroom in your amp to be able to do that. 

And maybe there are some numbers in the middle of the set where the same flexibility would be useful as well. It depends how well you know the program material and how closely you're working with the artists. There might be a huge crescendo that you switch off the limiters for because it's only a few seconds long. That sort of thing. (er, well probably not switch them off but, you know, let a few more dB of peaks through)

There's obviously a bit of an art to utilising headroom in that way and you would need to quite intimately know your rig and be using proper high spec drivers, ideally ones from manufacturers who have a reputation for surviving under extreme conditions like PD.

Do it incautiously or with cheap components and even if your bits survive they'll have long term damage that'll accrue over time and cause them to fail sooner. But do it carefully with live uncompressed music - and only when really necessary, and it won't be any more damaging than playing a night of heavily compressed but well limited bass heavy electronic music.

The other reason for lots of amp headroom is lower distortion. When you're playing up close to the limits of the amp you're also going to be getting distortion from over-excursion, intermodular distortion, distortion from power compression, and probably a few other sorts of obscure distortion I've missed no doubt. If you can avoid an extra 5 or 10% THD+N from the amp in peaks on top of all that, because you had another 3dB of headroom available before it went above 0.5%, you'll be glad for that.


Edited by Hemisphere - 15 August 2017 at 7:09pm
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gen0me View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gen0me Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2017 at 9:07pm
If you want to exact numbers its not doable:
Diffrent amps ratings
Different speaker ratings
Different music
Different singers

If you want to see how many db you need in the mix point of view go to studio and ask them to mix vocal in 2 ways as above and compare it to live music and compressed music. You will see how far is db meter moving. And at the end compare their dsp capabilities to your dsp capabilities.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Conanski Quote  Post ReplyReply Direct Link To This Post Posted: 18 August 2017 at 3:30am
Originally posted by gen0me gen0me wrote:

If you want to exact numbers its not doable:


That right there gets to the core of the problem, there is no simple answer. You can size amplifiers and set limiters to extract every last dB of performance from a given set of speakers for any 1 track, but all bets are off for any other track. Yes it is that specific, change any parameter in the recording or the live performance and the limiters have to change if you want maximum performance. So on top of the basic requirements you always have to write off some performance potential simply because you don't want to be readjusting limiters all the time.

And why are there different limiter settings for different program material. It comes down to what the speakers can handle. They can only survive a constant signal like a sine wave or synth tone at relatively low power levels because that builds hugh amounts of heat that will melt the glue holding the coil on the former which quickly leads to a dead driver. But they can handle many times that power for very short periods of time(miliseconds) which is all a kick drum lasts. Live vocals and guitar lands somewhere in between these two in terms of duty cycle but that also depends how much processing has been applied, think compression, sustain, etc. So this is why there is no simple answer and why you should always err to the side of caution with limiters, you can always relax them a little if a particular event isn't as taxing on the speakers as you anticipated, but if it's the other way around the limiters won't do anything and drivers will blow before you realize what is going on.

I will also add that subs are the most at risk part of the system with bass heavy recordings and performances so this is where you should pay close attention to limiter settings on a by event basis, with mids and highs you may never need any settings other than program level.


Edited by Conanski - 18 August 2017 at 3:41am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote charlysays Quote  Post ReplyReply Direct Link To This Post Posted: 18 August 2017 at 2:31pm
Can't comment on live music really as its another ball game entirely... but for parties and DJ nights/ rave music generally I feed my speakers their AES rating in watts RMS, maybe a little more (like 200-300w).

Yes I am running the sub amps flat out with little or no headroom, but they are running at 8r which is best off a 13a socket. Not blown or smelt any speakers in over 2 yrs like this, sometimes doing all night raves.

At the end of the day so long as you have set your limiters and filters correctly and are using the amp within its specs (avoid 2r like the plague even if the amp says it can do it, that includes 4r bridged obvs) you can power an 800w sub with a 300w amp. Nothing is going to get damaged as you've got a brick wall limiter set to stop the amp clipping... everything is being used within its specifications.

Here are some examples in my setup.
18nlw9400 cubo subs- 1300w fed to each at 8r from a PQM13.
18nlw9000 cubo subs- 2.1kw fed to each at 8r from a bridged matrix ukp2100x

If you're using amps way more powerful than your speakers be careful with compressed dance music. A good rule of thumb when setting a limiter to limit power as well as stop the amp clipping is that 6db subtracted off the crossover output band halves the power of the amp supplied by that band. -3db would be a 25% reduction in power. I've used these rules of thumb a few times to protect my speakers from being overpowered.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Hemisphere Quote  Post ReplyReply Direct Link To This Post Posted: 18 August 2017 at 2:49pm
Quote They can only survive a constant signal like a sine wave or synth tone at relatively low power levels because that builds hugh amounts of heat that will melt the glue holding the coil on the former which quickly leads to a dead driver
Yea those long low frequency synth notes certainly create a powerful sense of dread. The longer the note, the more dread.


Unless you use an RMS limiter.


Edited by Hemisphere - 18 August 2017 at 2:50pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jngggggggg Quote  Post ReplyReply Direct Link To This Post Posted: 19 August 2017 at 2:52am
That leads to my next question. Why is it so detrimental to run an amp at 2 ohm? Jumping from 2 to 4 ohm essentially doubles my power costs so it's a significant bump
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