Narrowing the stereo field of the low end?

Posted: Sun Aug 20, 2006 1:14 am

I understand that narrowing the low end is often done when mastering for vinyl, but is this ever used when mastering for CD?

Is it desirable to go mono with frequencies below, say 200hz?

Thanks,
Mark

Moderator Joined: Sep 12, 2002 Posts: 1881 Location: NYC

It's done for vinyl for mechanical reasons. You can do it for CD if you want but not for any real technical reason. It can seem to focus the low end, but that would depend on the mix. 200hz seems a bit high though. If you have some nice chunky guitars or a stereo piano, it would make them a bit thin sounding.

Posted: Sun Aug 20, 2006 7:05 pm

Yeah, I agree with Mike- 200 Hz seems a tad high (you're likely to run into issues with male vox and low guitar with that frequency).

If a mix is a tad lacking in the punch department, I will use Sequoia's built in stereo enhancer in multi-band mode to bring stuff from 90 Hz (the lowest setting possible in Seq) into the middle of the mix more. It can make a world of difference even though it's usually subtle.

J.

Posted: Sun Aug 20, 2006 9:55 pm

I sum below 100 or 150 hz all the time. Anything that low is generally unidirectional anyway. I use Sequoia's Stereo enhancer tool for this as well. It's great for this kind of thing, on the stereo output.

It's a nice way to focus the low end and clean up any messy rumble and "Junk in the trunk" down there. Anything above that 100 to 150 and upwards gives all the direcitonal cues you need.

Many systems are subwoofer equipped as well, so you'll get a good idea of what your stuff will sound like when using one of those, too. Maybe it's an analog leftover for me, but it's nice working from a solid foundation on upwards. The mono low-end does it for me.

Moderator Joined: Sep 12, 2002 Posts: 1881 Location: NYC

100hz seems a bit high for me too. If I need to clean up the sides a little, 40-50hz does it for me. anything higher than that can really change the depth of a mix. I couldn't find anything that I liked that was on the market so I designed my own. you also have to be careful about phasing out the subs when you push them into the middle. You might be better off filtering instead of combining.

Posted: Mon Aug 21, 2006 7:59 am

I think the trick is not to make it entirely mono. If that were the case, then 100 is too high. Usually, I bring it between 60 and 80% of original width.

Personally, I don't subscribe to the assumption that bass is entirely omnidirectional. I do believe it's harder to localize, but not impossible. For the longest time, I couldn't figure out why my system sounded off, but something was clearly wrong. My sub was located in the corner behind my left speaker.

I decided to move it inside next to my right speaker and voila - the system sounded MUCH better.

Since I listen primarily to classical and in about 95% of the orchestras in the world, the basses are on the right (audience perspective), the low frequency needed to come from that direction. Bear in mind, my sub is crossed over at 32 Hz, so there wasn't a lot of information there, but enough to throw me off.

Sorry - tangent over.

Posted: Mon Aug 21, 2006 11:41 am

Bass being omni directional is not a theory. It is a fact. But I agree that two LF sources can be identified because of time/distance relationship between the ears and the two sources and then the effects of the first, second and third, etc order reflections of a room's boundaries.

Posted: Mon Aug 21, 2006 1:42 pm

sheet wrote:

Bass being omni directional is not a theory. It is a fact. But I agree that two LF sources can be identified because of time/distance relationship between the ears and the two sources and then the effects of the first, second and third, etc order reflections of a room's boundaries.

Well....not quite.

To be a fact (or in science, a "Law") it must be proven beyond a shadow of a doubt using the scientific method (albeit a tad dated and corny, the principle is the basic concept when creating a scientific law).

The fact is - it has not been proven - rather it has been quite disproven. Bass, by its nature is less directional than higher frequency, but by no means truly omnidirectional. I won't go into a lot of details (as much of the work behind what I'm referring to is afterall classified), but their has been a lot of work and research into using amplified sound waves as weapons. Some of the more effective ones are directional low frequency waves. If they were truly omni-directional, they could not be "funneled" into an effective weapon without killing or severely injuring the weapons' operators. (Although Hitler did try to do so using large concrete structures as his horn if you will. This proved quite ineffective as the concrete would not hold up very well to what was essentially seismic activity.

J.

Moderator Joined: Sep 12, 2002 Posts: 1881 Location: NYC

It all depends on how big your head is. bigger heads, the lower frequecy you can get direction cues from.

Posted: Tue Aug 22, 2006 4:48 pm

Just remember that elliptical EQs aren't a free lunch - there's a crossover point you're going to have to woorry about...

Posted: Tue Aug 22, 2006 5:34 pm

Well, I hate to disagree with such esteemed folks opinions, but I'm fine with going to mono from around 100hz, sometimes even up to 150 if necessary, depending on the material.

We can differ on bass omni-directionality, (is that a word?) but most home systems now have subs, even cars do now; and it's anyone's guess where they get placed. I've seen some strange stuff out there, I'm sure you have too. Most stuff below 120 is going to be mono as a result, even on many high end systems. (I'll bet you can count on one hand how many folks you personally know with more than one sub in their system anyway.)

I think we'd all agree that in most cases, the sub-bass/ultra low end (20-40 hz) is being felt, not heard, regardless of where you put the box. To my way of thinking, it's all summed to mono down there anyway, and there's less chance of phasing issues or conflicting info coming at the sub from mis-matched or weirdly panned low end.

My own sub is adjustable from 80 through 120, and for my space, I've set the curve of my sub to match my mains at about 80-90hz (which is probably lower than most consumer subs). So, I get a little of both speakers info when summing this way; it's not just the sub telling me what's working or isn't.

In trying for the most transportable mixes as possible, at least to my way of thinking, a good solid low-end is a great foundation to build the rest of the mix on. Aside from a few unusual circumstances, I just think of all low end as mono, and build up from there. I'll mic tymps or double bass sections in the orchestra; and pan accordingly for L-R coherency in the mix, but I'll still sum the low end to mono. It fills up the mix, yet you KNOW where it sits onstage due to the HF cues.

For cheaper and less involved systems without a sub, anything below 80-100 hz mostly disappears anyway. This way, I'm good on the cheap stuff as well as the turbo-charged.

Posted: Wed Aug 23, 2006 3:28 pm

75hz is where FM radio puts a hipass filter, so if you mono-ize 75 and below, your stuff should have the same spatial feel over the air as it does on a full-spectrum wav file at home. At any rate, this is one of many reasons to clean up the low end. Just my two cents. I'm new to the forum, have been experimenting with this lately. Definitely looking for recording friends (my band just glazes over when i start in with the technical talk)

Cheers,
Nate

Moderator Joined: Sep 12, 2002 Posts: 1881 Location: NYC

yep, eliptical eq's... yes the crossover and phase shift can be a problem. Or it can sound good. Depends on the mix and such. Not sure how your programs are filtering and summing, does anyone here know?

Moderator Joined: Sep 12, 2002 Posts: 1881 Location: NYC

CrackBuddha wrote:

75hz is where FM radio puts a hipass filter, so if you mono-ize 75 and below, your stuff should have the same spatial feel over the air as it does on a full-spectrum wav file at home. At any rate, this is one of many reasons to clean up the low end. Just my two cents. I'm new to the forum, have been experimenting with this lately. Definitely looking for recording friends (my band just glazes over when i start in with the technical talk)

Cheers,
Nate

Nate,
welcome to the forum. lot of cool guys and gals around.

Posted: Thu Aug 24, 2006 12:03 pm

Thanks Michael Smile

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