Excuse me everyone if I'm getting to technical here, but I couldn't resist myself to throw some more light and explain myself with simple words, by taking one example from this post, considering EQ.
Again, I want to stress enough the fact that with the example that I'm giving,
I'm NOT trying to ridicule the person by exposing his 'mistakes', and showing myself as a 'superior' to him....
NO, this is
NOT my intention!!! If those settings work for him, and he likes how his keyboard sounds, I'm absolutely fine with that, and I'm not judging anybody.
Everybody is free to ignore what I'm about to say, but if this ends up helping somebody reading it, I'll be more than happy that I helped someone in some way, so let's crack on.
I've saw John early explained those EQ settings from the picture below, and he did pretty good and simple explanation, but I want to elaborate a little bit more on that.
Starting from left to right:
1)
We see that there is +8dB over 140Hz - even the cheapest and crappiest 10" speakers can easily reproduce at least 80Hz at very high sound levels, no problem. So there is no practical reason to give so much gain mid-bass frequency, as long as you're working with speakers not bigger than 6". Such setting may also be very unhealthy for the subwoofers since this is approximately the highest frequency that a sub can reproduce, and if you're pushing it all night, every night like this, you can seriously damage your subs. So I would avoid those settings as any cost, and dial it at around 45-70Hz for 12" subs, 40-60Hz for 15" subs, and around 32-40Hz for 18"subs. and respectively +/-2 dB depending on the room, IF NEEDED !
Important !!! What is Q? Q-stands for
Q factor, that determines how 'wide' the resonator is in relation to the centre frequency....sounds complicated? Trust me it's not, if you let me rephrase it in simple words.
If you imagine the shape of two mountains, one has very pointy top and very steep sides, and another that has very rounded and wide top and gently sloped sides. If you draw an imaginary line through the middle of the mountain, from the highest point to the bottom, this is your frequency 'centre'. The bigger the Q number is, the wider the sides of the mountains are...the smaller the number, the mountain is thinner and sharper.
If you translate those shapes on the frequency graph, the 'mountain' becomes the so called resonator/oscillator. The bigger the Q number, the wider the resonator is, so takes over the neighbouring frequencies around it's centre frequency, and wider band of frequencies are 'involved' in the following EQ process, and vice versa with the smaller Q number.
*EDIT few days after the original post, as reminded by Lee Batchelor:
Critical mistake!!! It's the exact opposite of what I just said. The higher the Q number, the thinner the band wave is, and vice versa, so read everything below in reverse relationship.
2)
+9dB over 315Hz with 0.7Q - here is where I would probably dial mid-bass from 120-200Hz and start to consider which diapason of those frequencies my PA in it's entirety can cope safely under high SPL(Sound Pressure Levels).
3)
-6dB over 560Hz with 4.3Q - so what I see here is fairly wide band of frequencies that are turned down, I can't guess the reason why is it so.
From here on, I can't give you any advices what you should dial, since there is no such thing as 'universal' EQ settings that will sound wicked on anything, in fact...there is such setting, and this is FLAT which I'll encourage everyone to chose.
4)
+4dB over 800Hz with 6.6Q - I'm starting to notice a certain Q pattern here, the higher the frequencies go, the wider the Q becomes until they basically overlap after about 3.0kHz all the way to 10kHz, but at the same time less and less gain is added to each frequency, otherwise the overall sound would have been even more tinny and harsh in the mid/mid-high diapason.
5)
-7db over 1.3kHz with 8.4Q - human hearing is very sensitive in this frequency band and it is easily perceived even by the people who have difficulty in hearing. Again, we see very wide Q band which has been turned down because is very piercing.
6)
-8dB over 3.6kHz with 11Q - Q band is getting wider, and it resulted in significant intervention over the amount of dB needed to 'subdue' the thinning of the sound.
7)
-7dB over 5.6kHz with widest possible Q - again, we're keep adding more and wider band of high frequencies, but than, we have to turn them down because it sounds thin and high pitched. And this is still mid-high diapason where human hearing is still very sensitive.
8 )
-6dB over 10kHz (I'm surprised how the keyboard didn't pop-up a message "System Error. Run out of Q"...just kidding
Here is where I'll advice everyone to double check your HF(high-frequency) driver specifications, in order to dial this setting to your specific speaker. Adult man/woman above 70 y.o. with averagely good hearing, will struggle to hear anything above 12kHz (there is always exceptions of coarse), although it is scientifically proven that women in general have slight advantage over man in this aspect.
Noticed something curious in this order and gaping of frequencies?
From knob 3 to 7 there is exactly 10kHz frequency range in total (from 560Hz to 5.6kHz) , and since the Q is quite wide in overall, so there is not a single frequency gap at all along from knob 5 to 8, and than there is massive, nearly 5kHz frequency gap ONLY between knob 7 to 8. That could have been spread much more reasonably so there is no big frequency gaps, and the overall sound would have been much fuller and richer...anyway, this is just an example.
So, how to conclude all this...simply use Flat EQ in 90% of the time, because it's practical, true to ears, convenient and very professional.
Know your PA, and use the EQ as a chef uses salt...to much of it spoils the dish. Use EQ to fix imperfections in speakers, not in keyboards.
I wish everyone lot's of fun playing with your keyboards, whether professionally or at home.
Yours,
Valentin