Room frequency measurments

[JoeESP9]

It looks like you have some relatively minor resonance aberrations in the low end. Room treatments are the best way to correct those.

 

[patate91]

It looks like you have some relatively minor resonance aberrations in the low end. Room treatments are the best way to correct those.

Where on the graph I can see this?

 

[JoeESP9]

To start with you have a dip at roughly 70Hz in both channels according to your first graph. Your last graph of RT60 shows a rising response below ~500Hz. That would tend to "muddy" the bass. I'm not trying to be overly critical. However, you did ask.

The sort of in room response irregularities you show in your graphs are exactly why I resorted to a DSP when a dedicated room and extensive treatments failed to completely smooth in room response.

E-Stat has posted his 1/3 octave in room response curve. I wish mine was that smooth without using a DSP.

 

[patate91]

I hope I can do without à DSP.

Not that I don't like the idea, the main thing is that Il can't afford tout change my amplifier. Even more if I need two. I know I can do it with a multi channel amplifier but I don't want to sacrifice on quality. But inside me I know that one day I'll go active .

I'll try to find E-Stat's post

 

[Bob in WI]

So the micrpphone is cheap enough & the software is cheap enough. But looking at the software instructions, I'm thinking there's way more in there than I need. Anyone know a link that has tuning your room instructions? I guess I don't figure to be an acoustic analyst so I just want "do this to get that" & it means this.... sort of thing. I'll admit, I'm finding it all somewhat confusing.

 

[patate91]

So the micrpphone is cheap enough & the software is cheap enough. But looking at the software instructions, I'm thinking there's way more in there than I need. Anyone know a link that has tuning your room instructions? I guess I don't figure to be an acoustic analyst so I just want "do this to get that" & it means this.... sort of thing. I'll admit, I'm finding it all somewhat confusing.

You can easily take measurements without readind all the REW instructions.

The umik is usb and I used my usb dac as output, so no calibration was needed.

For the rest, just experiment. A measurement sweep is 5 sec. Try moving your listening chair, move your acoustics panels, etc.and measure after each modification. REW will overlay everything , pretty simple. Then, do like me and ask for help .

I Found a lot of youtube tutorials too.

 

[patate91]

You can blindly tune your room, like I did first, but not knowing exactly what you are correcting and what your mods are doing across the spectrum, will make it harder to really improve things

 

[Bob in WI]

You can blindly tune your room, like I did first, but not knowing exactly what you are correcting and what your mods are doing across the spectrum, will make it harder to really improve things

Thats what I figured. Additionally, I'm reluctant to spend money on bass traps until I know what frequency I'm trying to modify & am confident the traps I buy will absorb that frequency. I'll poke around you tube.

 

[mars_volta]

I've been using a Dayton imm-6 mic on my android. Cost about $16

 

[patate91]

Thats what I figured. Additionally, I'm reluctant to spend money on bass traps until I know what frequency I'm trying to modify & am confident the traps I buy will absorb that frequency. I'll poke around you tube.

I'm trying to find which design I'll use. I have to keep cost as low as possible.

I have an old matress that I'll use to experiment on the next days, + a couples of other ideas

 

[Bob in WI]

I've been using a Dayton imm-6 mic on my android. Cost about $16

Do the results seem realistic?

 

[mars_volta]

Yes. I am using the Audio Tool app and it has a calibration file for the mic. Pretty impressive.

 

[patate91]

Today I moved my speakers! I managed to smooth the reponse.

Still no bass trap. I covered the TV with a bed cover. The 2 doors are now open.

My speakers are now closer together, and as far as I was able to put them on the rear wall. I toed them at the sitting place to get a dead center image.

The soundstage improved, I'm really satisfied.

1/6 smoothing
Red = old measure
Yellow = New measure, sitting correctly
Blue = New measure but slumped on the couch (which happen a lot late at night)




No smoothing


RT 60


I'm sure I can get things a little bit better by adding one corner bass trap in the corner next to my sitting place. I did some tests with an old matress and filled with cushion from floor to ceilling and it was better. I found that the aquarium is causing a part of the 60-70hz dip. There's certainly something more I can do there.

 

[E-Stat]

E-Stat has posted his 1/3 octave in room response curve. I wish mine was that smooth without using a DSP.

It took lots of experimentation with both speaker and trap placement. Having said that, the speaker position and my listening position is pretty close to HP's "Rules of Thirds". Contrary to usual guidelines, I get more linear response by stuffing all the big traps in the front corners. I'm also blessed with a 25x16 room that nearly matches the Fibonacci ratio, aka "Golden Ratio".

Clearly, an RTA plot would look more jagged, but nothing is terribly out of whack.

 

[JoeESP9]

Yeah, you cheated. You got the "almost" perfect room.

 

[patate91]

Camille Saint-Saëns Symphony no3 on Commence Minor op 78 never sounded that good

I moved my 100 gallons aquarium around and it appeared that it was helping with the 50 to 80 Hz.

I smooth the 200hz by adding a foot test right in the middle of the room.

For the next days I try to lift those speakers, st more than 200 lbs it will be a challenge!!!

 

[Bob in WI]

It took lots of experimentation with both speaker and trap placement. Having said that, the speaker position and my listening position is pretty close to HP's "Rules of Thirds". Contrary to usual guidelines, I get more linear response by stuffing all the big traps in the front corners. I'm also blessed with a 25x16 room that nearly matches the Fibonacci ratio, aka "Golden Ratio".

Clearly, an RTA plot would look more jagged, but nothing is terribly out of whack.

Those are considerable tube traps. Did you make them? What did you use?

 

[E-Stat]

Those are considerable tube traps. Did you make them? What did you use?

I think you've already discovered answer in "LP Stacks" thread. Yes, DIY recipe.

 

[patate91]

I tweaked the setup a little bit today.

Measurement at 95 db the response is within the range of +/- 3db a lot

Getting bellow 92 db at : 320hz to 354hz, 1.19khz to 1.97khz (biggest dip), 6.8khz and up (this range varies depending a lot on microphone placement)
Getting above 98 db at : 26.5 hz to 52.6hz (biggest peak), 679hz to 762hz.

1/6 smoothing
Purple = old
Gold = new



No close-up 1/6 smooth


No smoothing


I need to find a way to ''boost'' the 1.19khz to 1.97khz range and 6.8khz and up. Maybe with plastic sheet on acoustic panels???

 

[patate91]

I worked hard to tweak everything. Speakers are at ear level, about 5''1/2 higher.

I still can smooth some frequencies but I'll lose to much in RT60 et EDT. I think I just found a good balance : it sounds good, it image good, the soundstage is good, there's plenty of bass and lot of details.

Again no money were spent and there's no subwoofer in the room.

Purple = old
Blue = new

1/3 smoothing


1/6 smoothing
There's not a lot of frequencies that goes higher or below 3 db. Below 6 db appears at 16.1khz. I cant smooth between 250 to 350hz, but I lose a lot of decay time.


Psychoacoustic smoothing


RT60 data

Green = Topt
Purple = T30
Black = T20
Blue = EDT


Waterfall



In order to keep the balance I will have to find a corner bass trap that reflex highs. Any suggestions on DIY solution?

Any advices are welcome, I'm new to room measurement, there's a lot a thing I still don't understand.