can anyone tell me what this means?

[jimmyklane]

Can you PM me higher resolution versions of those? I can tell you what you'll need to fix to flatten out your room.

[soultrappa]

sure jimmy

[jimmyklane]

Ok... I clicked and saw them better.

You have a large room mode and it's second harmonic screwing with your bass response. See the dip there around 90Hz, and the second, smaller one at around 180? I'm guessing that when you listen to mixes done in that room, they end up either flabby, or with too much bass.... correct?

[seen-da-sizer]

Originally Posted by soultrappa

What can i do to sort out these graphs and is the high end ok?

Your HF gets cut off above 10KHz by more than 30dB. Something is just not right. Could be something like a broken HF tweeter. Or a microphone having problems above 10Khz.

[jimmyklane]

Are you mixing with full range monitors, or sat/sub? I'm HOPING full range, as that will be easier to fix, most likely. at 9ft x 5ft (with 8 ft ceilings?) your bass response is just not going to go that far down... a low E at 41Hz is almost 28 ft long if the math in my head is correct, and you have nothing CLOSE to that much room... so that big bump you're seeing at 45-50Hz is build-up and bounce from the corners and floor/ceiling junctures, I'm betting...

[jimmyklane]

seen-da-sizer,

I see his high end issue as a measurement mic positioning issue. in a room that size, he's probably having serious cancellation issues.

soultrappa,
Are the walls directly to the sides of your monitors covered with some 3-4" pyramid foam? if not, they should be, as THOSE are first-order reflection points.... also, the ceiling directly above mix position should have more of the same in a 4'x4' square if you can manage it. you are NEVER going to make this an ideal room to mix in, so the idea is to deaden your first and second order reflections that are causing phase cancellation on the high end ( what you'll hear as sloppy imaging and crappy transient response, along with "ringing" in the room) and bass trapping with REAL bass traps (as in a Hemholtz device) in the rear of the room.

[soultrappa]

I am mixing with krk vxt 6's and the 10s sub. The mic i am using to pick up the sound is a miktek cv4 and the pre amp is the focusrite saffire liquid 56.

And stangly enough no - not many end up to bassy but doesn't that depend on what note is playing?

[jimmyklane]

Yeah. I bet if you play a low E or F note, it's much louder than one octave up... like, by a bunch. that's what the graph is telling me should happen in your room, where the mic was placed.

[soultrappa]

Yes the walls directly by monitors are covered bar some rectangle spots - they are staggared. none on the ceiling.

are you telling me that in this small room im getting that much cancellation on the hi-end?

[soultrappa]

the mic was placed in the listening position - i have a graph of the mic placed a foot behind and omg

[jimmyklane]

OK.... your high end measurements cant be trusted. I thought you were using an actual measurement system.... maybe we should concentrate on the low end first, and I can help you out via email or phone as I suggested in the PM you sent me. there are some things that are universal good ideas that you should be able to try that will help out quite a bit.

Also, I'd love to see a picture of the room itself. If I see that, I'll know what's on the walls already, and approximately what it's doing to the sound from your monitors/sub

[soultrappa]

Of the mic placed a foot behind listening position (sorry forgot the image)

[jimmyklane]

tell me, if you stand in the middle of your room and clap your hands loudly, do you hear a "ring" or "wobble" sound at all? like a bad spring reverb unit?

[Jens Eklund]

Originally Posted by seen-da-sizer

Your HF gets cut off above 10KHz by more than 30dB. Something is just not right. Could be something like a broken HF tweeter.

X-over to tweeter is seldom higher than about 5 kHz, normally around 2-3 kHz. I guess the OP has either done the classic mistake of measuring both speakers simultaneously and if the microphone is not centered exactly in-between L & R speaker, destructive interference will occur, in the highest range if the difference in arrival time between the speakers is small. The other explanation would be the use of a diffuse field microphone (aimed towards the ceiling as is normal) that normally results in a HF drop at around 15 kHz (or lower if cheaper DF model, or even worse; a free field mic used as a DF type; aimed at the ceiling and not towards the speakers).

Why point the mic at the ceiling?

[soultrappa]

mix side of room

i have included a pic of front view - will take of back tomorrow in better light

[soultrappa]

strangley enough not really - to the hand clap. Before i put the foam up there was a definate flutter echo but now the sound just seems to be sucked away - not much ringing at all. but by the graph those main freqs dont look to be that bad.

[soultrappa]

classic mistake of stereo speakers - the program (fuzzbox auto took control of that and i didnt think.

[soultrappa]

ok no just checked and fuzz only plays via left montor mic is facing forward (in between monitors) but is in omni.

[Jens Eklund]

Originally Posted by jimmyklane

Are you mixing with full range monitors, or sat/sub? I'm HOPING full range, as that will be easier to fix, most likely. at 9ft x 5ft (with 8 ft ceilings?) your bass response is just not going to go that far down... a low E at 41Hz is almost 28 ft long if the math in my head is correct, and you have nothing CLOSE to that much room... so that big bump you're seeing at 45-50Hz is build-up and bounce from the corners and floor/ceiling junctures, I'm betting...

You don’t need a 28 ft room to support 41 Hz. 4,2 meters is enough to reach 41 Hz with the first axial mode, but depending on the ratios (and thus the modal frequency distribution) the first octave or two will naturally be a bit shaky, even with proper treatment.

[Jens Eklund]

OP:


After seeing the pic of your room: ditch the thin foam treatment and do it properly (if possible):

Sticky with links?

4m x 5m x 2.5m room - modal resonance problem

[soultrappa]

What about the foam traps.
and I'm worried about the hi end now. Tested sweeping with sine and freq analyser. Still drop ofd but by around 15 db from 10k to20 k

[soultrappa]

Best way to test tweeters?

[Jens Eklund]

You’re using a large-diaphragm microphone, not the best type of mic to do acoustic measurements with so I would actually be surprised if you got usable data above 10 kHz. Unless your response sound weird (play a 10 kHz sine and then a 15 kHz sine and just listen I they sound about the same in terms of level), there’s probably nothing to worry about in terms of FR above 10 kHz (decay times might be a different story due to all the thin porous treatment).

[diggo]

Originally Posted by soultrappa

What about the foam traps.
and I'm worried about the hi end now. Tested sweeping with sine and freq analyser. Still drop ofd but by around 15 db from 10k to20 k

Ignore it.

Focus on low frequencies below 400Hz, with particular focus below 200Hz.

High frequencies go direct from tweeter to ear - comb filtering from high frequency reflections is the least of your concerns.

Low frequencies typically exhibit more extreme behaviour due to modal ringing and SBIR. Those factors influence what you hear more than anything else and (in small rooms) you have to control low frequencies. Until those aspects are dealt with effectively, anything else is merely conversation.

Sean

[DanDan]

Those big visual lumps at LF are a problem. Peculiar to Fuzz.
Make the IR 'Window' in FuzzMeasure longer. If necessary make it almost or fully as long as the duration of your graph. This will remove those big blips and show you the modes normally.

DD

[Jens Eklund]

And use 1/24 octave smoothing (if any):
Before posting your measurement results

[soultrappa]

Thanks guys for all the help. What exactly do u mean dandan?

[DanDan]

This is just the first file that I came upon, but it happens to be an extreme case. I have to increase the Window to 500mS to clear up the blips as you can see.
I would call this a 'bug' in FuzzMeasure.




DD

[soultrappa]

I used 500ms -75 in the shots I provided. Do u mean u want a less broad freq range?