Equalizer

[Thad E Ginathom]

Try once again asking yourself -
Do I really want to add another useless component in the signal path ?

It's useless if you have perfect ears in a perfect room. As it is, an equaliser is actually (impossibly huge windfalls excepted) the only thing I am now likely to add to my hifi other than replacing items that die.

Most of us do not have much more than a general idea about what an equaliser actually does: a tone control with lots of sliders rather than just two knobs. Or something like that.

I haven't got any experience with the real physical beast, but I have been experimenting with PC audio and Eq in software. It's a good idea to do this to get a feel for what an equaliser will do for you (and, perhaps, what it won't.) For starters, my conceptual lots of sliders rather than just two knobs is probably a graphic equaliser --- so called because the shape made by the sliders looks like a graph. Each slider is labelled with a particular frequency.

A Parametric Equaliser is a much more complex beast. Each knob/slider is not labelled with a frequency: there is another control for you to set the frequency that that slider controls. And another to set how wide the range of frequencies it controls should be.

It's a knob twiddler's paradise! Gadget heaven! And maybe we get some sort of result, in the end, by trial and error, but. along the way, we find that there is going to be less trial and error if we start learning what instruments/voices are to be found at what points on the frequency scale.

Here's one I prepared earlier

That little peak, for instance, was some chinky-chinky percussion that I was not hearing at all before applying Eq (so no, not useless).

Actually, my desktop studio-equipment rack is a bit broken just now, but when I get it mended, I'll get back to learning, and to hearing the chinky-chink bits hyeah:

I'm doing all this to "correct" for high-frequency hearing loss. I'm listening mostly with headphones, so room correction does not come into it. Even so, it is quite complex: room correction would be a whole other trip! If I wanted to do that, I'd go for something like the Behringer beastie, which, I believe, has a function to take mic readings at the listening position and create and Eq curve to compensate. Then I'd have to use that as a base and add hearing correction.

As is often the case with my longer posts, all this could be put in a few words: an Equaliser is not a plug-in simple answer, it takes quite a lot of effort to create your own answer with it.

I'd also suggest that using it to remove "colour" that a particular piece of equipment has added would be particularly difficult. The diagnosis would be tough. It's the old story: audiophiles hear a difference, engineers can express the difference in numbers.

 

[trittya]

+1 to FM Thad E Ginathom for that post.
Whats not covered here is best left unsaid.
Very well brought out, as usual.
Regards

 

[Thad E Ginathom]

Thanks, trittya.

I might just add that I entirely agree with Shivam in principle about the simplicity of the signal chain and not adding anything that is not necessary. I would, for instance, be concerned (at least in theory) about the analogue/digital/analogue conversion manoj.p draws attention to above. This means that the ADC/DAC sections must be at least as good as one would want if, say, adding a stand-alone DAC to a system. Weakest link and all that.

In terms of reputation, Behringer is not a premium-price brand, it is a brand that offers some very good value for money. A search here would reveal that we have at least one delighted audiophile using that box for room correction EQ, I think we also have some users of their monitor speakers too.

Really, in terms of cost and practicality (the sophisticated piece of kit pictured above was, of course, free) the PC is the ideal place to do all this stuff. But no, that is not very useful advice to the proud owner of a high-end CD player, and even less so to Vinyl people.

 

[trittya]

Thanks, trittya.

I might just add that I entirely agree with Shivam in principle about the simplicity of the signal chain and not adding anything that is not necessary. I would, for instance, be concerned (at least in theory) about the analogue/digital/analogue conversion manoj.p draws attention to above. This means that the ADC/DAC sections must be at least as good as one would want if, say, adding a stand-alone DAC to a system. Weakest link and all that.

In terms of reputation, Behringer is not a premium-price brand, it is a brand that offers some very good value for money. A search here would reveal that we have at least one delighted audiophile using that box for room correction EQ, I think we also have some users of their monitor speakers too.

Really, in terms of cost and practicality (the sophisticated piece of kit pictured above was, of course, free) the PC is the ideal place to do all this stuff. But no, that is not very useful advice to the proud owner of a high-end CD player, and even less so to Vinyl people.

Couldn't agree more with you, Sir.
Ideally speaking, I too would like to have it the way you and the Learned doctor said. But, OTOH, it doesn't quite HAPPEN, whether its a case of room interaction, design/driver/component (read premature bass roll-off etc) constraints/inadequacies or in some cases even poor recording. Thats where an EQ comes in handy, not only to boost/bump-up but also to attenuate certain particularly harsh frequencies.

Having said so, I am not in favour of suggesting/tending to see all problems as a NAIL just because ONE'S ONLY TOOL IS A HAMMER.
I was an all-EQ guy when I was in my teens and until much later. Somewhere down the road I underwent a change of perception and hence, of opinion and went doc Shivam's way. Now, I live happily in the middle-of-the-road in this regard. my decision to be so was largely influenced as attributed hereunder:-
* I reckoned that EQ cant be all that bad if iconic designers like Siegfried Linkwitz, John L Murphy and the like use it extensively for correction and/or customization of the reproduced sound.
* I reckoned that its worth a trry if it makes the music more enjoyable, the shades of so-called PURISM in me, be damned.

Nevertheless, I must add here that there are some recordings/albums that I invariably listen to in flat mode, if not by entirely disconnecting the EQ (doing that very time is rather cumbersome). Some that come to mind, offhand, are:-
- most Pink Floyd, Bob Marley and Dire Straits albums.
- most fusion albums
- Jethro Tull - Thick as a brick
- Roger Water - Radio Kaos
- The Who -Tommy
- et cetera
Its worth mentioning here that to my ears these sound better w/o EQ in a 'normal' listening environment.

I daresay that I do NOT understand much of the finer nuances of room interaction from a scientific standpoint, maybe thats why I resort to using EQ as a trial-and-error tool, only as and when required. More often than not, it seems to work.
So far so good, eh?:yahoo:

The point that as trying to make is that by not dismissing EQ as entirely useless, one does stand to accrue some sonic/aural pleasure. Then again, over EQ is not my preferred cup of tea but it must be said here that its very easy to step over the very thin line between optimal EQ tweaking and over-EQ. Thats like using your music to listen to the EQ rather than using you EQ to enhance the (sound of) your music.

Cheerio

 

[manoj.p]

There are lots of people who absolutely hate equalizers. It's either love or hate. But we need to understand that the equalizers are used at every process in the mastering and studio. The audio that people revere so much has gone through tons of equalizers in the mastering process. No matter how much people are in denial but that's the truth.

When its played back, the listening room is the biggest equalizer. Our rooms are not anechoic chambers and we are not in open. The room changes the very sound as output from the speakers. People are again in denial about this but its a fact.

However, that does not mean that we should put the equalizer back into the chain right away. Equalizer is a very powerful tool in changing the sound and like every powerful tool, has bad effects if not used properly. The room effects should nullified through placement, treatment and then equalizer. One needs to understand what they are doing with equalizers, know how that equalizer works (whether its PEQ) and then set the filters properly. Also, the equalizers usually work for a seat. So, there could be bad effects at other seating location. You raise a peak at certain frequency for main seat, it can cause a dip or null at some other location. One needs to be careful and use it wisely.

 

[Thad E Ginathom]

Room correction really is science. Reflections is fairly easy to grasp, but then one comes across stuff like "standing nodes!"

It is really amazing to think that one can spend the maximum, select the best, on equipment, and still have holes in the frequency spectrum because of the room one puts it in. Hifivision has made me more aware of this stuff than I was in the previous 40 years of listening, but I doubt that I'll have the chance to set up a proper listening room and the hifi si currently crammed in a space that doesn't even allow a proper stereo image. Thank god for headphones! But I really appreciate the people here who understand the acoustics of a room --- and I accept, too, that some of them have an instinct that short-cuts the maths.

There's an unexpected side effect to all of this, though: in some halls it makes me think about where I sit. Somewhere, I read that even moving the head a few inches can make a major change to our listening. With Chennai's bad sound systems, changing seats or rows can make all the difference between acceptable and inaudible!

 

[himadri]

Room correction really is science. Reflections is fairly easy to grasp, but then one comes across stuff like "standing nodes!"

It is really amazing to think that one can spend the maximum, select the best, on equipment, and still have holes in the frequency spectrum because of the room one puts it in.

During my hifi journey after upgrading to high resolution usher mini dancer1 speakers and the subsequent anomalies introduced by the room, I had to resort to relatively near field listening in the smallish 12x14 room to eliminate the room as far as possible.Introducing my earlier sonodyne uranus equalizer from my earlier system just horribly degraded the sound.
Finally cardas speaker placement (relatively nearfield) and corner d.i.y bass traps turned out to be the most even sounding in the room.
Guess digital equalization and the subsequent analogue conversion for amplification would have to of very high quality and cost to compensate for the room and give an equivalent sound quality especially as compared to an all analogue system .
cheers

 

[debzkool]

I have shortlisted 3 equalizers

1) Behringer FBQ1502
2) Behringer FBQ800
3) DJTECH Soundgraph 1502

All the 3 are within my budget and to my liking feature wise.

Any suggestions, need to finalize soon.

 

[manoj.p]

Room correction really is science. Reflections is fairly easy to grasp, but then one comes across stuff like "standing nodes!"

It is really amazing to think that one can spend the maximum, select the best, on equipment, and still have holes in the frequency spectrum because of the room one puts it in. Hifivision has made me more aware of this stuff than I was in the previous 40 years of listening, but I doubt that I'll have the chance to set up a proper listening room and the hifi si currently crammed in a space that doesn't even allow a proper stereo image. Thank god for headphones! But I really appreciate the people here who understand the acoustics of a room --- and I accept, too, that some of them have an instinct that short-cuts the maths.

There's an unexpected side effect to all of this, though: in some halls it makes me think about where I sit. Somewhere, I read that even moving the head a few inches can make a major change to our listening. With Chennai's bad sound systems, changing seats or rows can make all the difference between acceptable and inaudible!

You nailed it. Every time someone is buying an equipment, they ask about how this will sound, what is the quality of speakers, cables, source players etc. But the biggest differentiator - the room. No one discuss about it. Or it is discussed after the fact. More like I got this equipment and now how do I set it up.

About the room correction - yes its quite complicated. There its better to start with good placement and taking care of the room first. Reflections are quite easy to take care with absorption/diffusion. But you rightly said, the "standing waves" are quite nasty to take care of. For example, a 40 Hz sound wave is 28 ft long. In a room shorter than 28 ft, it will hit a wall and reverse and then mix with the original wave. One can try to absorb it but will need huge absorbers and will suck the energy out of bass. One can use multiple subs distributed across the room (like what JBL/Harman suggests) to cancel the reflections each other. But that can only work up to where the subs are crossed over. What about above 80 Hz and upto Schroeder frequency?

All one can do is find a sweet spot in the room where the bass is more or less consistent. There will always be peaks and dips but find a sweet spot where the frequency response is somewhat flat and does not have any nulls.

 

[sdurani]

...we find that there is going to be less trial and error if we start learning what instruments/voices are to be found at what points on the frequency scale.

Here you go:

Interactive version can be found here (worth bookmarking). When you're at that page, you can slide your cursor up & down, left & right and watch the info on the right side of the page change to give you more details.

 

[Thad E Ginathom]

Thanks, sdurani. Yes, I know that page, and it is my regular reference too

 

[manoj.p]

Here you go:

Interactive version can be found here (worth bookmarking). When you're at that page, you can slide your cursor up & down, left & right and watch the info on the right side of the page change to give you more details.

Welcome back. Hope you stay around longer this time.

 

[reubensm]

Came across this old thread and thought I'll add a post as I keep getting the odd request on suggestions for a good EQ. Actually the funny part of this is, many ask about EQs in hush-hush tones (at times, reminds me of the old nirodh advert that doordarshan used to show in the 80s). But jokes aside, its like an audiophile talking about a taboo subject, its something that is not supposed to be found on a high quality rig, a person who uses an EQ is automatically disqualified from discussions on hi-fi equipment and high quality sound reproduction, etc.

I too belong to the school of pure analog signal paths and started off with 'flat' sound (tone defeat). I had grown up in this 'flat' world as dad was a purist and autocrat (well-read and built his own stuff). However growing up, i happened to land up in a class at school with a few American returned NRI kids. Tape trading and lending was common in those times (yes, even in Trivandrum) and very soon, I started listening to MJ, Madonna, Tina Turner, Cindy Lauper, Lionel Richie, Stevie Wonder and a whole lot of Eurodisco. Then one day, a cassette came my way titled - Bon Jovi - New Jersey. Once I heard this cassette, the others seemed quite irrelevant and very soon, MJ and Madonna were replaced by AC/DC's Blow Up Your Video, Ozzy Osbourne's Ultimate Sin, Europe's Wings of Tomorrow and Final Countdown and Judas Priest's Defenders of the Faith, then came Van Halen's OU812. Cutting to the chase, when my music taste changed, I found the 'flat' world to be very boring and un-inspiring. Then came the tone controls (we used to call them tone boards), first passive and then upgraded to baxandall. Still not enough, then came the idea of feeding one baxandall tone control into another and thus I reached a stage where I decided to build a DIY EQ. I tried a 5-band one with OP Amps and found it to be better than using 2 tone control boards but it had limitations (in those times, we listened by ear and did not have the means or gear for lab measurements). The inadequacies were more to do with significant colouration, noise and distortion. Scrapped everything and went back to using an amplifier with a single tone control board, with a few modifications for deeper bass and higher treble response. A loudness control built into the amp compensated for the loss from removing the second tone control board. When i switched to NAD gear, in tried many popular EQs with a NAD pre-power combination and noticed the same issues which i faced with my DIY EQ back in the day. Every time I tried out an EQ, after a few days I would go back to my original NAD pre-power setup (you may be wondering why i wanted to tamper with the NAD signature sound. Its not that i wanted to change the neutral NAD sound, but i wanted to roll off a few lower mid frequencies that were causing my boomy bass). Gave up plans to every indulge in EQs and went back to the tone controls on the amp.

During my travels, I had the opportunity to listen to a live band perform at a Hotel in London, everything sounded so nice and natural. Although they were playing some pop and folk tracks, the quality of the sound was really good (even though they were using regular PA). After the show, i curiously walked up to the mixing board to check out what they had. Its there that I noticed this device called the Ultrasound Pro (Behringer DEQ 2496) and during a small chit-chat with the guy at the board, he said - all that you hear is due to this little box. That started my look out for this box. During my travels I could not find one in good condition at a reasonable price (this is an expensive piece of gear). I put it on my wish list and meanwhile did a lot of reading on it, online. Almost everyone talked about using this box in home studios, professional recording studios, live rigs, etc but almost nobody spoke of home hifi use. Anyways, a few years past by.

Then last year, i just dropped a post in our wanted section and got lucky with this box in almost new condition. It took me a while to figure out how to get it to work but once I did, I soon realized that this is what I was looking for. This is perhaps the best ever EQ there has ever been. I got exactly what I wanted in terms of sound but more importantly, I have presets for different genres of music (i used to have friends who use to pass comments like - Jazz sounds wow, great on his rig but Motley Crue sounds like the music is coming from an earthern pot - incidentally referring to a Quad II and Quad 22 rig)

I am yet to use the digital inputs and outputs on this box am yet to explore room correction, etc but as it is, it sounds fantastic. The parametric EQ can be used to enrich the sound (especially when playing low quality youtube music). I also had to build XLA to RCA cables to wire it to my rig. But I can safely say, if you ever want to invest in a good EQ that you'll be happy and content with, look no further than the Behringer DEQ 2496. Here is a similar experience for reference.