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EQ

A

abbydog

pfm Member
Was playing with one of these this weekend in a fit of nostalgia

http://www.hifiengine.com/images/model/adc_sound_shaper_two_equalizer.jpg

Like surround and quadraphonic, they come around like the decades and then fade out.

Occurred to me doing this in DSP must be cheaper but that's about it really - oh, and you probably need less fader lube. And get less fun.

Maybe I need one of these

http://i.ytimg.com/vi/6sSjf5Wskws/maxresdefault.jpg

to get the job done right. Does anyone really think there's much to be gained from the latest Brit-fi 'room correction' fad?
 
Well it would be like doing it in DSP if it had hundreds more sliders and they had a much wider range of adjustment.
 
there is a huge amount to be gained from room correction , or even just eq in the bass for your listening position. Old school slider type analog eq is not the way to go , DSP is
You can try free room correction in the time and freq domain with trial programs like Dirac or Acourate or play with the parametric eq on most puter based players.
 
I'm rather skeptical of EQ in a home audio context to start with, but old graphic equalisers really are rather nasty things IME and best avoided. I say that as someone who owned a couple in a studio context. I remember taking one home, an Alesis IIRC, and trying it in my then Linn Naim system. It sucked the life out when flat and was far to crude to do anything useful.

If a room/system is really hopeless even after sensible positioning of the kit, listening seat and some decent furnishings, carpet etc*, then maybe a digital solution is worth having, but only in the knowledge you are likely making things more 'wrong' at all but the listening seat.

*A studio 'live end / dead end' approach is well worth perusing IME, i.e. for any opposing boundaries (walls and floor/ceiling) have one that either absorbs or scatters/difuses. I've never had to go beyond this to get a sound I'm happy with, but by saying that I'd never rent or buy a house with a bad sounding listening room. I'd prefer to move! Large record collections, book collections etc are huge assets when it comes to nice sounding rooms. Position them wisely!
 
Very popular in the 70s and 80s, remember growing up when my mates dad had a rather expensive JVC with 20 band graphic equaliser and always fiddled about with it, thank god I got into Naim gear during the 80s just volume and balance :D
 
My basic experiments with EQ to see if it lives up to the hype gave me a positively pleasant surprise. I expected it to be arguably better, but in actual fact it was simply better - however, my test was with my speakers in horrible places to try and increase the value of the test and pulling them into good spots was better than the EQ'd improvement coupled with my concern that asking my speakers to provide lost signal (mostly in the very LF region) probably means I'm asking more of them and won't be able to go as loud.

The thing that stops me from going forward is that I don't want more boxes, especially if they were passive. Eek. When EQ arrives in my DAC and only fiddles with the digital part of the signal I'll feel more comfortable.

I've never liked EQ as much as I have recently and considered it a dirty word. I even avoid amps with tone controls. Might be habit.

Keith, what's the difference between EQ and DRC? Genuine rookie question btw! :)
 
Using EQ you can deal with very narrow, specific frequencies , modern sophisticated EQ allows you to choose the amount of reduction and the width of the EQ 'bell' , digital room correction corrects the whole frequency response, although having said that Dirac for example allows you to only correct a portion of the frequency response.
So you could choose just to correct a narrow bass region for example.
In my experience EQ is transparent.
Keith.
 
RC should also work in the time domain , which plain EQ doesn't
Dirac and acourate work like that .. not just freq adjustment.
It's debateable whether DSP actually works above 500hz or so.. treatment is the answer there
simple tone controls can be semantically called EQ .. they act too grossly to be really useful.
Dont worry about asking the speakers to do stuff in the low end that they cant , you should never really use DSP or Eq to boost .. flattening peaks however will give you tons more amp headroom and it will allow the driver to work in an optimal state at that point .. less motion and excursion etc results in less distortion.
Eq can not be transparent , it does change the signal, however if used in the digital domain and is a good program , it doesnt introduce any distortions and doesnt make areas it is not acting on any worse.
the ideal is to exhaust physical option like diffusion , absorption , bass trapping etc and then apply DSP room correction/eq
 
Sibbers said:
Keith, what's the difference between EQ and DRC?
Click to expand...

EQ is a general term, meaning the modification of the amplitude/frequency and/or phase/frequency response of a given system.

DRC is the application of EQ to the problem of turning the combined speaker/room response into a desired response, at one specific listening position.
 
Cheers, I guess I was confused by the fact that it takes EQ to correct the problems created by the room. Seems like the same thing with the difference being one is fixing something while the other is tuning to one's taste.

When I pull the speakers away from the wall I get all those lovely low frequencies, but right next to the wall I have to ask more from the speakers to ensure they are projected. Admittedly it does sound almost as good, so I am a fan.
 
Can a link for for a primer 101 on what a deep analogger needs to know before committing to equipment and only now gathering and thinking digitally at last

I recall was it Soundcraftsman 'Holographic Equaliser' was the marketing depts dreamachine

However a primer as to what bits and boxes are needed in order to use EQ in the room

I get the microphone bit but from there on ....
 
Sibbers said:
Cheers, I guess I was confused by the fact that it takes EQ to correct the problems created by the room. Seems like the same thing with the difference being one is fixing something while the other is tuning to one's taste.

When I pull the speakers away from the wall I get all those lovely low frequencies, but right next to the wall I have to ask more from the speakers to ensure they are projected. Admittedly it does sound almost as good, so I am a fan.[/
Passive treatment, EQ and DRC are all used to try and correct problems /issues raised when you place a pir of loudspeakers in a room.
You can use all three to tailor the sound to taste.
There should be more bass when the speakers are placed tight into corners because of reinforcement, when you pull the speakers away you will be actually cancelling some of the speakers rear bass projection, so there may be less bass at those certain frequencies.
Keith.
Click to expand...
 
ian r said:
Can a link for for a primer 101 on what a deep analogger needs to know before committing to equipment and only now gathering and thinking digitally at last

I recall was it Soundcraftsman 'Holographic Equaliser' was the marketing depts dreamachine

However a primer as to what bits and boxes are needed in order to use EQ in the room

I get the microphone bit but from there on ....
Click to expand...

A lot depends on what boxes you already have and what you are trying to do.

As Tony says above, analogue EQ has a bad reputation. Some people don't like digital EQ either as they claim it too damages the sound.

Anyway, I use an equaliser between my separate CD Transport and DAC, so it operates only in digital. The alternative is to use an ADC to convert analogue to digital, do the digital EQ, then use a DAC to convert back to analogue. Some, like my Behringer DEQ2496 and the ten times more expensive DEXQ, and Keith's MiniDSP with DIRAC, have all this in one box and you can choose to use any or all the components.

When using a CD player/DAC in one box this means two sets of conversions, unless the CD player has digital outs.

In other words you will be relying on the quality of the EQ's ADC/DAC. Those in the Behringer aren't supposed to be that good (I can't really comment) but you can get modifications to improve them.

The three products I mentioned can all do measuring using a microphone. I actually use Room EQ Wizard to do this, as it's a much more sophisticated software and is free, but takes some learning.

Before using an EQ for adjusting for the room I advise trying to get the best sound firstly with placement of chair and speakers, and secondly with room acoustic treatment. My EQ just tidies up after these.
 
I (could be wrong) assumed that it was to do with the rear port and size of the wavelengths for lower frequencies being limited by the nearby reflectors (walls) in some of the directions.

From my analysis using an iphone app which goes from (a reported) 31.5hz up to 16k I got less bass below 50hz close to the walls and more around the 125ish region - pulling them out into the room into their ideal spots things flatten out really nicely... I think... I should check that ;)

Like I say, I am a rookie, so I appreciate all the guidance but essentially I used an EQ to flatten out what my iphone thought it could hear. I'm sure it's terribly inaccurate but it seemed to work.
 
Standing waves are determined purely by the rooms dimensions, bass at lower frequencies in almost omnidirectional , bass waves aren't limited.
If you type your rooms dimensions into an online room node calculator ,the Huniceke ? one is good ,that will give you an idea of the potentially problematic frequencies in your room.
Keith.
 
I did give that a shot, but I just couldn't work out what it all meant. I even saw a graphic which showed some funny blue lines. I think that all the frequencies fit into the room, but... well, I'm learning (you might disagree ha!)

None the less, I get more bass when the speakers are pulled out. I think my room, while small, is pretty kind in terms of the effect of the listening experience.

It's 4.1 x 3.1 x 2.4m and it has a bay window at one end and a chimney breast in the other corner taking a diagonal chunk out. Sounds wicked. Maybe my speakers are kinder than I realised but each amp upgrade appeared to reduce what seemed like room resonances (to me).
 
All the frequencies, even the very lowest will fit into your room!
If you acoustically measure your room you will see exactly the relationship, if there is a problem with resonance you will immediately see it.
I wouldn't expect changing amps to make much difference unless your previous amp was incapable of driving the loudspeakers, ie perhaps producing less bass than it should have been.
Keith.
 
Thanks for the handholding, I have Rega Planet mk 1 with a very large indeed digital out
I think coax size

So to apply room EQ I have to access the digits en route to the CB Naims. That is the DAC and I further assume the EQ is programmable into ...any? DAC or only newer models?

I have esl57's and early early non dual concentric Tannoy 12 inchers. One lacks bass t'other lack treble or at least needs a clear shot at delivering what is available

Am I in the zone?
 
MiniDSP for example is high quality and inexpensive, you measure your room with measurement software, Room EQ Wizard is free, you then perform the correction/EQ on your laptop , you can listen to it on the fly.
Download the correction to the MiniDSP hardware , there are a variety of processors, analogue or digital ,and a number of 'plug-ins' to perform anything you can think of.
Once downloaded you disconnect the computer and the hardware just sits in your system.
Keith.
 
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