[Michgelsen]

This is an interesting read. Rane has published other interesting papers too, about clipping for example.

 

[grokit]

Quote:

Originally Posted by Shark_Jump /img/forum/go_quote.gif Don't know much about Active Room compensation. Is this only for high end? It makes a lot of sense, in theory anyway, any links?

How about SOCS - Speaker Only Correction Software?

It is proprietary code, and only runs on the Perpetual Technologies P-1A, which is an upsampling DAC and "room compensation engine".

It claims to be "the first of a new breed of real-time digital processing systems able to eliminate all phase and amplitude error from any speaker system as well as nulling room interactions for an optimized speaker-to-room-to-listener interface".

Pretty good reviews with lots of info on the second link.

Here's the catch: the P-1A is discontinued, and the new model is not out yet.

Mark seems to be pretty on top of it, hopefully he will have a new version out soon...

 

[Shark_Jump]

Quote:

Originally Posted by Michgelsen /img/forum/go_quote.gif This is an interesting read. Rane has published other interesting papers too, about clipping for example.

I have to admit some of that is a bit over my head.

In his last point is he saying for an equaliser to properly correct a room response you have to be able to adjust phase as well as amplitude?

Do some equalisers allow you to do this?

 

[Michgelsen]

I'm no expert either, but as far as I know, analog equalizers always cause phase shift. That is one reason why audiophiles don't like equalizers.

What the writer of that paper is saying, is that not only frequency response changes, but also phase shifts occur in a room. Hence, you need not only to fix the frequency response, but the phase shifts as well. That's why, he argues, it's a good thing that equalizers cause phase shifts.
I'm not sure whether that's a valid point. It seems to me that phase shifts caused by the EQ are in a fixed relationship with the amount of boosting/cutting. When you need to compensate for room acoustics, you can't know whether that predefined relationship suits your room.
But don't take my word on it, because I'm not expert as I said.

Here's a link by the way to a manufacturer who makes digitally compensating equipment: Lyngdorf.

 

[Redcarmoose]

A room with speakers are one thing. People use subs with controls just like EQs were used in the 70s and 80s.

With headphone systems each part of your set-up performs the roll of an EQ. Some cables are dark some cables are bright. Some headphones are bright and so on. When everything is set up the way you want it you just enjoy the diferences of your sourse material. Some material requires different headphones which are the ultimate form of EQ. Most of the time adding another componant just gets you one step farther away from your source. If componant wise we are able to adjust the EQ why would we want to add another set of cables and another componant to get us farther away from the sound?

 

[sbtruitt]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif You'll find a lot of them available in the pro field. I don't use one because my view is that if you need equalization, then you have a problem somewhere along the line. I'd rather address that problem directly than twiddle a knob only to cause a problem somewhere else.

I disagree - a room+the default curve of a set of speakers and/or your own ears can help from using an EQ. I have used them for years with great benefit - and it doesnt necessarily mean something is wrong to want to get the right signature or response you want.

In the case of using it for my HP setup, it turned my very good D2000s into great for me. If there are 'perfect' headphones out there - I havent heard them yet (or I cant afford them) - but using just a bit of compensation in a few key places - *for me* - mine now sound excellent.

 

[nick_charles]

Quote:

Originally Posted by Michgelsen /img/forum/go_quote.gif I'm no expert either, but as far as I know, analog equalizers always cause phase shift. That is one reason why audiophiles don't like equalizers.

There is some ambiguity about how much phase shift you need to be an audible problem, some AES research (Blauert and Laws, 1978) suggest that we cannot detect phase shift of less than 36 degrees.

 

[sbtruitt]

Quote:

Originally Posted by Ham Sandwich /img/forum/go_quote.gif What does your EQ curve look like for the D2000? I've been using a software based 31 band graphic EQ to mod my D2000. I've just been focusing on the 1K to 4K region trying to balance out the recessed frequency range that the D2000 has there. I've also tried some various parametric EQs. But I find the graphic EQ easier to deal with as long as it has enough bands.

Me too. I took my mic, rapped it in a tube of foam, and used that in place of my ear inn the ear pads for getting it flat - what I saw was close to the headroom curver for the D5000 (which with my mods I think I am more like) - it it worked pretty well as a starting point. Crude - yes - but worked for me.

The tweeks for my D2000 were:
-3dB@125hz, +6dB@500hz, +3@2Khz, -3@4Khz, and +6dB@16khz

the main one for me was reducing the 4Khz area a bit which with some material was a bit sibilant and could cause some fatigue. I'm sure mileage (and ears) will vary, but for me this works quite well.

 

[sbtruitt]

Quote:

Originally Posted by Redcarmoose /img/forum/go_quote.gif A room with speakers are one thing. People use subs with controls just like EQs were used in the 70s and 80s. With headphone systems each part of your set-up performs the roll of an EQ. Some cables are dark some cables are bright. Some headphones are bright and so on. When everything is set up the way you want it you just enjoy the diferences of your sourse material. Some material requires different headphones which are the ultimate form of EQ. Most of the time adding another componant just gets you one step farther away from your source. If componant wise we are able to adjust the EQ why would we want to add another set of cables and another componant to get us farther away from the sound?

The point is these other parts of the chain shouldnt be an EQ, are not easily or cheaply changable (transducer, room, ears, source material) and an EQ is a quick, flexible way to tweek the sound to fit your tastes, or change the EQ for a specific speaker or HP you have - and, if you dont want it you simply click a button and you are bypassed.

 

[Shark_Jump]

Quote:

Originally Posted by Michgelsen /img/forum/go_quote.gif I'm no expert either, but as far as I know, analog equalizers always cause phase shift. That is one reason why audiophiles don't like equalizers.

If equalisers are used by the recording industry why aren't they good enough for audiophiles?

Can modern equalisers overcome the phase shift 'problem', assuming it even is a problem anyway?

 

[sahwnfras]

Quote:

Originally Posted by Shark_Jump /img/forum/go_quote.gif If equalisers are used by the recording industry why aren't they good enough for audiophiles? Can modern equalisers overcome the phase shift 'problem', assuming it even is a problem anyway?

Because if the signals already been equalized why should you have to equalize it again. Thats his job, not mine.

 

[Shark_Jump]

Quote:

Originally Posted by sahwnfras /img/forum/go_quote.gif Because if the signals already been equalized why should you have to equalize it again. Thats his job, not mine.

I was using the point about recording studio eq to question if phase change was an issue.

But to answer your question effects such as room and speaker resonances, transients and other system responses will change the sound you actually hear at your ears. Sometimes significantly.

If you are very lucky and you have a good listening environment, or spend a lot of time and money to get this right, you can reduce these effects.

Or if you have lots of money as you say 'thats his job not mine' you could get the recording engineer to visit your house and set your graphic equaliser for you!

 

[9pintube]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif You'll find a lot of them available in the pro field. I don't use one because my view is that if you need equalization, then you have a problem somewhere along the line. I'd rather address that problem directly than twiddle a knob only to cause a problem somewhere else.

Amen, You don't need more whistles and bells in the signal path....I.M.O.

 

[gilency]

If you are going to use an equalizer, a parametric one gives you better control.
Most people around here rather choose components until they find the perfect match and that is fun and great if you have the money. Or you can correct (if needed) frequencies that are to high. It is better to decrease than to increase. And remember it wont make a Beyerdynamic T1 out of a cheap earbud.

I am not being fictitious here: they help, to an extent, but won't convert iron into gold.
Some parametric equalizers allow you to correct for irregularities in the room by using a microphone to automatically adjust its settings. The cheapest one I know is the Behringer DEQ2496.

 

[Shark_Jump]

Quote:

Originally Posted by 9pintube /img/forum/go_quote.gif Amen, You don't need more whistles and bells in the signal path....I.M.O.

Thats fair enough, but don't forget about those nasty room and speaker effects hurting those lovely signals before they reach your ears.