Fact check, please.

Chris Nixon

Junior
Jul 23, 2012
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Northern Ireland
I've just read this article:

Chris Trimby: Monitor Engineer

It contains this paragraph:

"I did a gig in Bristol where they had been struggling with their monitors. The graphic looked as though someone had fallen over and pulled the faders with them. I had a listen to the monitors and they didn't sound very good, so I flattened the graphic and listened to the boxes flat. They were bi-amped, so I asked the house engineer to turn the high end down a couple of clicks on the amp. He asked if he should do it on the crossover, but I said 'no, on the amp'. We turned the amp down a little bit and the monitors sounded a lot better; a little bit of EQ and they sounded great! When you turn a crossover down, it turns down, say, 2dB of the crossover, but then if it then goes into the amplifier and the amplifier is too big, turning the crossover down 2dB in proportion to what it's going to amplify is a meaningless action. Turn the amplifier down. Quite often especially on monitors, the amplifiers are far too loud for the high end. In places where people don't have enough experience, all that is needed is someone to take things back to basics. If you find yourself hacking away with a graphic EQ, the problem is rooted somewhere else in the chain."

I'm all for flattening the graphics, but 2dB is 2dB isn't it?

Chris
 
Re: Fact check, please.

Why have output level knobs on the crossover at all if his is the correct method.

I prefer to leave the amp attenuators at "0dB" as it's much harder for a casual user to accidentally turn things up higher -and for the regular user one quick glance at the amps can tell if anything has been changed versus trying to always remember certain channels are at -2, others are at -6 etc...

Of course with DSP crossovers it's easy to lock them out so that their "knobs" aren't as easily changed and if they were then a quick preset recall gets everything back to nominal.

If a HF device is grossly over-amped (such as thousands of watts into a 1" tweeter) that an amp adjustment is required then think about changing to a more appropriate size!
 
Re: Fact check, please.

The writer of that article seems to be lacking a basic understanding of amplifier gain - turning down the gain knob on the amp doesn't prevent it from reaching full power. It just changes the sensitivity.
 
Re: Fact check, please.

Hmmmm........The last time I checked 2dB = 2dB. The only way turning down the crossover output a couple of dB would be meaningless would be if 2dB had no meaning. What are they teaching the kids these days? Back in my day we always carried a screwdriver in case we ran into one of those crossovers John designed.
 
Re: Fact check, please.

Hmmmm........The last time I checked 2dB = 2dB. The only way turning down the crossover output a couple of dB would be meaningless would be if 2dB had no meaning. What are they teaching the kids these days? Back in my day we always carried a screwdriver in case we ran into one of those crossovers John designed.

That's why John now suggests that people use powered speakers so they can't misadjust the crossovers.

JR
 
Re: Fact check, please.

I've just read this article:

Chris Trimby: Monitor Engineer

It contains this paragraph:



I'm all for flattening the graphics, but 2dB is 2dB isn't it?

Chris
I disagree. Kinda

If talking about analog crossovers-I would agree-but with digital it is different.

By turning down the amp-you not only reduce the gain (same as turning down the level on the crossover), but you also reduce the system noise by the same amount.

In a DSP (in most cases) reducing the output level by a couple of dB still leaves the D/A converters in the line-which can add to the noise.

The noise is a system is most evident in horn drivers (due to the higher sensitivity)-so turning down the amp can also reduce the noise by the same amount-which does not get done by reducing the level on the DSP.

The overall tonality would be the same in either case.

Yes a dB is a dB and that is one of the beautiful things about the dB-that was started in place decades before any of us were born.

The ancients did a lot to make our life easier.
 
Re: Fact check, please.

Yes a dB is a dB and that is one of the beautiful things about the dB-that was started in place decades before any of us were born.

The ancients did a lot to make our life easier.
But why do we say 20dB instead of 2B?

And why do we always put that ambigous minus sign in front of the dBFS-scale or the LKFS-scale?
 
Re: Fact check, please.

But why do we say 20dB instead of 2B?

And why do we always put that ambigous minus sign in front of the dBFS-scale or the LKFS-scale?

Why don't we use decimeters or dekagrams?

And the minus sign is not ambiguous, it signifies that the that the value in question is below the reference level (in this case, full scale).
 
Re: Fact check, please.

What are they teaching the kids these days? Back in my day we always carried a screwdriver in case we ran into one of those crossovers John designed.

It's not just these days, sound mixer persons have been spouting misinformation (of one kind or another) since I've been in the game, which is now well over 30 years.

And to give the guy a little bit of credit, if there is a limiter somewhere between the crossover output gain and the input of the amp, it could actually make a difference. Although he didn't mention that as the reason. Some times people are right, for the wrong reason. :roll:

GTD
 
Re: Fact check, please.

It's not just these days, sound mixer persons have been spouting misinformation (of one kind or another) since I've been in the game, which is now well over 30 years.

And to give the guy a little bit of credit, if there is a limiter somewhere between the crossover output gain and the input of the amp, it could actually make a difference. Although he didn't mention that as the reason. Some times people are right, for the wrong reason. :roll:

GTD
Yes to all.