Just plotted Frequency Response for Monitors, what's next?

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aznwonderboy

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Um...I did some reading before posting this. Granted, many posts have discussed the topic of using an SPL meter to measure the frequency response of room/monitors. However, I learned that those threads are very conflicting and confusing, often sidetrack, or offer solutions that I cannot afford to take.

I have plotted a frequency response graph of my monitors the SP-5B in my room. I am hoping that you guys can provide some quick fix to improve the response as much as possible without making me spend any more money.

Bass traps? - No thanks. Those cost money and a load of more headaches.
Move the monitors? - Sure. Um...how? where? Do I have to go through the entire test tone CD and graph the whole spectrum again after every little nudge I make to the monitors (that will waste a lot of time since plotting the whole spectrum took me an hour)?


Here's what I did to analyze my monitors. I downloaded a test tone CD. I put the SPL meter on a tripod at my ears' position right inside the equilateral triangle. Then, I played the pink noise and adjusted the volume on the monitors so that the SPL meter displays 82dB. {Some people used the tone 1Khz as the reference at 85dB. I didn't do this. Does it matter?} At that volume setting, I began to play each test tone and write down the SPL meter's reading at that frequency. Whoo! That was very tedious, especially with the bass test tones.

I am attaching my graphs. Please tell me what can I do with it?
 

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I prefer not to do anything to the room. I would rather know the characteristics of my monitors/room and adjust for them in the mix.

Sighs...but if I do this...then what's good the nearfield monitors? I might as well use the computer speakers, find out their characteristics, and adjust for them. I just want my mixes to translate better to other systems.

Based on my graphs...what can you tell me about the characteristics of my room and monitors? (I would assume that either the lows and mids are hyped...or that the highs are not giving flat response.) Which frequency should I use as a reference point so that I can adjust the other frequencies?

Please offer very simple solutions. Thanks.
 
aznwonderboy said:
I prefer not to do anything to the room. I would rather know the characteristics of my monitors/room and adjust for them in the mix.

Sighs...but if I do this...then what's good the nearfield monitors? I might as well use the computer speakers, find out their characteristics, and adjust for them. I just want my mixes to translate better to other systems.
Click to expand...
Whether you think this is a simple solution or not, it's the only solution for the parameters you allow. (It's actually the only solution no matter what, in the final analysis.)

1. Throw those charts out. Seriously.

2. Learn the characteristics of your monitors by ear. There are two ways to attack this, both of which you should use. First, take your favorite commercial CDs that you know how they sound in your sleep and listen to them on your monitors. I mean listen. Listen to the monitors themselves and how they color the music compared to your memory and compared to other real-world systems. Second, make a few mixes on the monitors until they sound right. Then take those mixes to other systems and see how they translate. These techniques will help you determine how to plan for that translation in your mixes.

3. The reason why good monitors still matter is that the computer speakers just will not deliver enough sound to give you an accurate idea of what you're doing. For example, if your speakers are low bass poor, you'll never know if/when you have mixed with enough low bass because the speakers will never deliver it no matter how much you adjust. Conversely, you'll never know when you have added to much either. Regardless of the acoustical characteristics of your room - even if you were to spend ten grand on traps, diffusers, clouds, etc., etc., - you'll never know if your adding or removing enough of any frequency if it's not coming out of the speaker with some accuracy (or at all) to begin with.

G.
 
Wow...thanks. I have been trying to learn my monitors too. I don't trust my listening skill yet, so that's why I want to use visual aid to help me strenthen that skill.

any more words of wisdom?
 
I can understand your desire for visual aid. The problem here is that unless you are using properly calibrated equipment to measure the response, the measuring equipment itself will be coloring the results. Simply put, they cannot be completly trusted to be telling you the truth.

I know it's tough to train one's ears satisfactorily and it takes some time and effort, but the benefits of doing so are immesurable. Your ears are the most important link in the signal chain. Until you have them reasonably well "trained", they will add their own heavy and unpredictable color to your mixes, no matter how good your equipment, acoustics and techniqes are.

It's boring, perhaps, but regularly doing the kind of "ear reps" described above with a variety of music styles and recordings is the best thing any of us can do. I've been at this for a long time and I still make a point of doing such practice reps fairly regularly to make sure I can hear changes due to aging of equipment, addition of new equipment, changes in environment, and even changes in my own ears as I get older.

G.
 
yeah I dont really trust those SPL meters to be very accurate but these charts make sense. There are similar peaks and valleys pretty close to an octave apart. Plus, 30 db swings in the bass end, I dont think the margin of error on the meters is THAT large, so something HAS to be going on there. There must be some truth in these charts.

That said, yes, try your speakers in different positions and re-chart. If you could get those swings cut down to 15 or 10 db you would be in much better shape. have fun! I might try this myself!
 
You at least need a calibrated meter, which means you need to know its response across the audible frequency range. I use a reference mic instead.

What I can see in your charts is that you probably have some nodes in your bass. That cannot be fixed by adjusting your mix. Whether you want to admit it or not, create a proper acoustic environment is critical for good monitoring (tracking too). Anything else is a compromise. Get some bass traps.

Your high end response looks normal for pink noise--if that is what your test tone CD was trying to approximate. If, however, each frequency on the CD was the same SPL, then you are looking at the performance of your tweeters, which doesn't look particularly good--good tweeters shouldn't rolloff until at least 12 kHz.

Once again, it could be the sensitivity of your SPL meter at those frequencies too.

Here's a thread explaining what I did using a reference mic and RTA software--it only takes 10 seconds of pink noise for me to plot this graph! COOLCAT did the same thing using free RTA software:

http://www.homerecording.com/bbs/showthread.php?p=1693339
 
try your speakers in different positions and re-chart. If you could get those swings cut down to 15 or 10 db you would be in much better shape
Click to expand...

Well, I put my monitors really close to the wall to enhance bass response...as I have read that the bass on these SP-5B's are weak.


What do people mean by re-positioning the monitors?
-Do they mean...face the monitors a different way (but I thought their faces are suppose to point at my face!)
-Do they mean widening/shortening the sides of the equilateral triangle (I space my monitors apart at 40")?
-Or do they mean move the computer's desk and the monitors to a different area of the room? (uhh...where's the best place in the room to move them? So, if that doesn't improve...I would have to move them somewhere else again? Man...unhooking all the cables and moving the desk would take so much time alone as it is.)

Right now I have my computer desk in a corner of the room. It's not a corner desk either. It's a rectangular desk...so I have my left monitor in the corner...and the right monitor ...not in the corner. The monitors and I form an equilateral triangle with sides of 40".

I have attached a drawing of my room. All the objects are very proportionate and in exact ratios relative to the room and to each other.
 

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Get the left speaker out of that corner. Swap the desk and the green shelf, maybe.
 
Your high end response looks normal for pink noise--if that is what your test tone CD was trying to approximate. If, however, each frequency on the CD was the same SPL, then you are looking at the performance of your tweeters, which doesn't look particularly good--good tweeters shouldn't rolloff until at least 12 kHz.

Here's a thread explaining what I did using a reference mic and RTA software--it only takes 10 seconds of pink noise for me to plot this graph! COOLCAT did the same thing using free RTA software:
Click to expand...

When I play the pink noise through Adobe Audition's Frequency Analysis...every frequency is pretty much at the same level; nothing rolls off. So, this could mean my tweeter is damaged....urghh....anyway to see if it is really damaged or not? Open it up and look for what signs?

So, using a reference mic and an RTA software will pretty much give me the overall frequency response spectrum of my speakers. (I wonder if the MXL V67G will do. The frequency response of the mic drawn by the manufacturer looks pretty flat). If using this method is such a time-saver, I wonder in why people use the individual frequency test tone to plot out point by point?
 
> I have plotted a frequency response graph of my monitors <

I agree with the advice to throw out those graphs because they're meaningless. Your low frequency response is much worse than what's shown, and you need to measure at 1 Hz resolution to see the true response. Your LF graph appears to be at 5 Hz intervals, and that's just not enough.

> Bass traps? - No thanks. Those cost money and a load of more headaches. <

Then you might as well sell your gear and learn to be an accountant. I am serious. You'll never get a decent mix if you can't hear what you're doing, and without bass traps you can't hear what you're doing.

> Move the monitors? - Sure. Um...how? where? <

That's a start, but even the most ideal speaker placement will take you only so far. You'll still have numerous peaks and deep nulls, and your room will still ring at all the mode frequencies.

--Ethan
 
mshilarious said:
What I can see in your charts is that you probably have some nodes in your bass. That cannot be fixed by adjusting your mix.
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Ethan Winer said:
> Bass traps? - No thanks. Those cost money and a load of more headaches. <

Then you might as well sell your gear and learn to be an accountant.
Click to expand...
Oh, come ON, people! Stop drinking the koolaid! :)

Room acoustics are very important, yes. I would never argue against that. But to say that one cannot get a great mix whilst sitting in a 15dB bass node, and that if they don't treat their room they might as well take up knitting is, at best, delusional, or at worst, an insult to the engineering skills of the person your talking to.

There are a half-dozen people on this board who, right now, could walk into aznwonderboy's room with good tracking and come out with a very good mixdown; one that would sound better than what most people could get at Paisley Park or Abbey Road. Even ones who spew the room acoustics mantra could do a great job in a lousy room if they applied themselves. There are another dozen or rookies so who could do the same after another year or three of solid experience.

Great rooms assist in great recordings, but less-than-great rooms do not exclude them. They can be, and are, engineered around all the time with excellent results.

G.
 
i think the key thing here is the aznwonderboy doesn't want to do the room, bass traps, rta/spl stuff or more importantly...doesn't really enjoy it.
if you enjoy the acoustics physics or whatever it is..
its much more..er...umm...enjoyable.


the whole idea, imo, of setting up the EE triangle, DIY bass traps, and such is trying to squeeze the flattest setup out of a sht box drywallroom, like my own, and to some its very enjoyable and interesting (believe it or not).

personal tastes, i enjoy tracking much more than mixing, as its quicker, more spontaneous, and i suck really bad at mixing! :p
no, really, it comes and goes.

Setting up the room is like tuning your guitar imo.
or tuning your carburator if your a motorhead, or tuning a fork.
 
SouthSIDE Glen said:
Oh, come ON, people! Stop drinking the koolaid! :)
Click to expand...

OK, two things: First, I am an accountant!

Second, what I am suggesting is don't try to fix a node in the mix. Bad idea. Your suggestion is to learn the monitors & room. Sure, that works, although it takes more time upfront, and as you go along since you'll spend more time listening on different systems to check.

Having seen the room layout afterwards, I don't think it's so bad. Beds make pretty good bass traps :) and the big obvious flaw is the monitor in the corner. Fix that--for free!--and I bet those graphs look much nicer :)

When I play the pink noise through Adobe Audition's Frequency Analysis...every frequency is pretty much at the same level; nothing rolls off. So, this could mean my tweeter is damaged....urghh....anyway to see if it is really damaged or not? Open it up and look for what signs?
Click to expand...

I really doubt they are damaged. I'm not sure what to make of that--pink noise, not white noise, right?

So, using a reference mic and an RTA software will pretty much give me the overall frequency response spectrum of my speakers. (I wonder if the MXL V67G will do. The frequency response of the mic drawn by the manufacturer looks pretty flat).
Click to expand...

It's best to use an omni--is the V67G cardioid? It's large diaphragm, so I would expect some variance in frequency response along its axis. It might work OK below 250 Hz, since mics are mainly omni there anyway.
 
I've tried to generate static sine waves through Cool Edit and noticed bizarre effects when walking around the room. Certain frequencies will almost double, then almost cancel depending on where my head is.

Hmmm...

I'm trying to remember if I've seen this somewhere - didn't someone mention something about stacking cardboard boxes in the corners adjacent to your monitors as a means of creating a cheap, makeshift type of portable bass trap? Could there be merits to this or is it snake oil?


sl
 
snow lizard said:
I've tried to generate static sine waves through Cool Edit and noticed bizarre effects when walking around the room. Certain frequencies will almost double, then almost cancel depending on where my head is.

Hmmm...

I'm trying to remember if I've seen this somewhere - didn't someone mention something about stacking cardboard boxes in the corners adjacent to your monitors as a means of creating a cheap, makeshift type of portable bass trap? Could there be merits to this or is it snake oil?


sl
Click to expand...
i found some of the cancellations and spikes very interesting. moving the speakers to and from the wall,upside down..etc.. it's for real.
and your ears do hear most the changes. i finally resigned to concentrating on the mix seat only, first.

the rta stuff helped quantify it all and made things go much quicker than using the ears and listening to various cd's.
if i turned up the treble it showed up immediately,

the bizarre stuff, i added the sub the 20hz to 100hz went all over the freaking place on the chart!! my ears didn't hear like that really...or did they? :eek:
the bass was randomly spiking and spiking and dropping..like a damn rollercoaster!!! and i wasn't touching anything, just pink noise playing!!!

wild, frkn crazy bass electrons and protons everywhere, i don't know how loud it was maybe 86db!! it had the chart noding out, man!!
and then i felt a cold chill!!!
and when i looked down at my feet one of my socks were gone!! :eek:
 
At the very least ... get the damn speakers out of corner.

Jeezus. Talk about a recipe for disaster. No wonder.


Secondly, get them away from the wall a little, if you can. You've got, what, two bed mattresses there? That should help out at least a little. If you could move a heavy couch or something in there, that would certainly help.

But Jeezus, dude. You're mixing in the corner. Get the heck outta' there. Then we'll talk about bass traps and room treatment or whatever.
 
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