Room measuring

[kininigin]

I have ordered a U-mik 1 which should be turning up today, as I fancy messing about measuring my room and see what's going on.

Will be a bit of a learning curve as I've never done anything like this before, so be prepared for some noobie questions when I can't work out to how to do anything :D

I have downloaded REW and I use J River. Will post screen shots of my progress.

[Magna Audio]

Will be interesting to see how you get on

Measuring and room correction on the sub bass channels has been fundamental to my setting up my system in two very different rooms.
Also getting the crossover points right, which type of crossovers to use where and time aligning all 10 channels.

I have also measured the effect of system upgrades that I can hear.
In terms of dB changes at certain frequencies, distortion and phase plot - changes in what you hear certainly show up.

I use Holmimpulse free sw and a calibrated mic with phantom pre amp in to the analogue input of my preamp.

I did use Jriver as steamer sw, but now use Qobuz hi-res, and Volumio / Kali reclocker over I2S.

[kininigin]

Well the mic wasn't delivered yesterday, so not been able to take any measurements yet :rolleyes:

I will be primarily focusing on how my subs integrate with my room and will be choosing 3 crossover points. I will first try 50Hz, 80Hz and 120Hz and take things from there.

I've been a bit dubious about using some form of DSP and maybe I'll give it a go but for now will just see what I can do passively.

[Mr.Ian]

I run a couple of servo 15 on the av side with digital eq via rew and behringer 2496 but for the mains I prefer analogue eq via a klark teknik dn410 with rel s series on the speaker terminals.

[kininigin]

Will be interesting to see how you get on

Measuring and room correction on the sub bass channels has been fundamental to my setting up my system in two very different rooms.
Also getting the crossover points right, which type of crossovers to use where and time aligning all 10 channels.

I have also measured the effect of system upgrades that I can hear.
In terms of dB changes at certain frequencies, distortion and phase plot - changes in what you hear certainly show up.

I use Holmimpulse free sw and a calibrated mic with phantom pre amp in to the analogue input of my preamp.

I did use Jriver as steamer sw, but now use Qobuz hi-res, and Volumio / Kali reclocker over I2S.

Wow, 10 channels! I can see why measuring and room correction is needed. Doesn't sound like you have a conventional system as such. Did it take you long to get everything as you wanted it?


I run a couple of servo 15 on the av side with digital eq via rew and behringer 2496 but for the mains I prefer analogue eq via a klark teknik dn410 with rel s series on the speaker terminals.

Nice subs ;) Can be beasts when needed! I did look at the Behringer when my crossover packed up.Did you ever use the X-30 crossover unit with the servo's and if so, did you find the Behringer a step up?

[Mr.Ian]

Ran servo 15 on the front for a long tine using x30 coss over on each channel but found a strata 3 in the speaker terminals worked better, ran a stadium for a while but too big. Now use the av processor crossover to pipe to the subs and a kramer switch on the mains to alternate between av and music, taken 20+ "years of experiment but generally very happy now

.

[Mr.Ian]

2496*only does eq no cross over, nothing wrong with with the x30 other than a lower limit if 50hz
Ian

[Magna Audio]

Wow, 10 channels! I can see why measuring and room correction is needed. Doesn't sound like you have a conventional system as such. Did it take you long to get everything as you wanted it?


Well it's 5 stereo channels but 10 drivers in all.
i use a Najda DSP X/O / DAC to receive analogue or mostly these days streaming from Qobuz Hi-res. It controls the speakers. I apply DSP correction only to the bass channels - I don't find the other
channels need it.
I cut at 31Hz and 79Hz to remove boomy room modes.
Never add dB to room correct. It sounds off if you do.
Anything above 150Hz or so also affects the sound negatively in my experience.

Najda was a DIYaudio developed project. Unfortunately the designer is out of he loop now.
Before that I used passive 2nd order crossovers on all channels, Zobel's and LPads to control the driver efficiency differences.
I added amps for each channel and then went active.
I dabbled with Behringer's DCX - needed 2 of them. It has a built in auto room correction system - not meant for Hifi imo.
The sound benefits of removing Lpads, Zobel's and X/O components was great.
The system has evolved a lot since then. Each attention to detail improvement giving reward (or it was put back as it was:) ).

[kininigin]

Well it's 5 stereo channels but 10 drivers in all.
i use a Najda DSP X/O / DAC to receive analogue or mostly these days streaming from Qobuz Hi-res. It controls the speakers. I apply DSP correction only to the bass channels - I don't find the other
channels need it.
I cut at 31Hz and 79Hz to remove boomy room modes.
Never add dB to room correct. It sounds off if you do.
Anything above 150Hz or so also affects the sound negatively in my experience.

Najda was a DIYaudio developed project. Unfortunately the designer is out of he loop now.
Before that I used passive 2nd order crossovers on all channels, Zobel's and LPads to control the driver efficiency differences.
I added amps for each channel and then went active.
I dabbled with Behringer's DCX - needed 2 of them. It has a built in auto room correction system - not meant for Hifi imo.
The sound benefits of removing Lpads, Zobel's and X/O components was great.
The system has evolved a lot since then. Each attention to detail improvement giving reward (or it was put back as it was:) ).

Ahh i see, all a bit out of my comfort zone but glad you've got it as you want it.


2496*only does eq no cross over, nothing wrong with with the x30 other than a lower limit if 50hz
Ian

I didn't realise you couldn't use the 2496 as crossovers! Glad i didn't buy one then ha.

[kininigin]

So i've received the Umik today and have taken a measurement of both speakers and subs from 20Hz to 22KHz.

The supplied cable is bit short of my seated position,so it's a couple of feet in front.

Looks like i have a few dips and a few peaks! Will see if moving things around a bit can help with that.

https://i.imgur.com/yEDq98t.jpg

[Magna Audio]

Can't see the first graphic. Shows broken link for some reason.

1/12 octave is pretty fine res.
Try 1/6 or even 1/3.
At 1/3 you are looking for +/-5dB across the rev range, as a good benchmark.
Even a -5dB plot can't really be heard as missing amplitude as you go down say, a walking bass line.

Bass room modes are pretty sensitive to distance from the drivers.
I can have bass boom a few feet in from the chair, and suck out in the chair!
Try to get a proper length cable, and re-measure.

I've always found with DSP room correction, less is much more.

Better to put up curtains, have thicker rug, books on shelf, even partition a wall etc etc rather than start cutting above 150Hz, or heaven forbid adding[emoji33] amplitude.

'Measures flat, sounds pants', is one of my mantras [emoji23]

[kininigin]

Can't see the first graphic. Shows broken link for some reason.

1/12 octave is pretty fine res.
Try 1/6 or even 1/3.
At 1/3 you are looking for +/-5dB across the rev range, as a good benchmark.
Even a -5dB plot can't really be heard as missing amplitude as you go down say, a walking bass line.

Bass room modes are pretty sensitive to distance from the drivers.
I can have bass boom a few feet in from the chair, and suck out in the chair!
Try to get a proper length cable, and re-measure.

I've always found with DSP room correction, less is much more.

Better to put up curtains, have thicker rug, books on shelf, even partition a wall etc etc rather than start cutting above 150Hz, or heaven forbid adding[emoji33] amplitude.

'Measures flat, sounds pants', is one of my mantras [emoji23]

Oh really, i can see it but maybe it's just me that can for some reason? Let me try again. Yes i'm using 1/12 atm but will try your other suggestions. I think my mic is where my bass dips a bit. In my seated position, i can definitely here more bass. I have ordered a longer cable. Should be here tommorow.

Have no plans to start using eq above 150Hz, if i do use any, it will be bass duties only!

Sorry, so can you see any graphics at all? I've only posted one so far.

[Magna Audio]

I can see the plot.
There's a broken link image before that, perhaps it's not of anything.

Sounds like you are on the right track.

[Mr.Ian]

Rew has a forecast tab that lets you dial in room dimensions and speaker poditions, then generates a forecast of response. Its pretty accurate. U would look at that first, see if moving the subs helps. Next i would try playing with subwoofer phase and crossover level. Go for some big wild changes. Like no subwoofers, 180 degree phase changes try to get able to get a mcheta feel for what effect different changes give. I think you will be able to get a better response before you start to eq

[kininigin]

Rew has a forecast tab that lets you dial in room dimensions and speaker poditions, then generates a forecast of response. Its pretty accurate. U would look at that first, see if moving the subs helps. Next i would try playing with subwoofer phase and crossover level. Go for some big wild changes. Like no subwoofers, 180 degree phase changes try to get able to get a mcheta feel for what effect different changes give. I think you will be able to get a better response before you start to eq

Yes I did see the room simulator but have not used it so far. I can only really move one sub due to layout of the room. Not had a chance to do any more readings but do now have a longer cable. Will try your suggestions sometime next week/weekend or when I get the chance.I'm hoping I can make some difference before thinking of eq'ing.

[bumpy]

Have no plans to start using eq above 150Hz, if i do use any, it will be bass duties only!


Do you still plan to pass the signals above 150Hz through the processor even though you wont be making changes there?

[kininigin]

Do you still plan to pass the signals above 150Hz through the processor even though you wont be making changes there?

Well I don't have a processor atm but if I do get one, I don't think I would pass signals above 150Hz. Maybe would temporarily just to see how it would affect frequency's above that.

[Magna Audio]

I wouldn't use room correction passing the signal though for just room correction!

The benefits of DSP crossovers, steep slopes on the bass channels, no Zobels, no huge inductors and capacitors, no Lpads to volume equal between different drivers and to be able choose between, Linkwitz-Reily, Bessel and Butterworth and choose 1st, 2nd, 3rd, 4th 6th and 8th order steepness , the ability to time align fully etc makes DSP absolutely the right choice for multi way systems.
Passive components to the level required suck dynamics.
Room correction on the deep bass is essential icing on the DSP cake [emoji3]

The level of integration and transparency DSP can offer has to be heard to be believed.
Not necessary for a regular 2 or 3 way passive radiating speaker though.

[kininigin]

I wouldn't use room correction passing the signal though for just room correction!

The benefits of DSP crossovers, steep slopes on the bass channels, no Zobels, no huge inductors and capacitors, no Lpads to volume equal between different drivers and to be able choose between, Linkwitz-Reily, Bessel and Butterworth and choose 1st, 2nd, 3rd, 4th 6th and 8th order steepness , the ability to time align fully etc makes DSP absolutely the right choice for multi way systems.
Passive components to the level required suck dynamics.
Room correction on the deep bass is essential icing on the DSP cake [emoji3]

The level of integration and transparency DSP can offer has to be heard to be believed.
Not necessary for a regular 2 or 3 way passive radiating speaker though.

I don't know what half of those words mean :scratch: :lol:

Maybe i should just buy a DSP processor and see what all the fuss is about! In fact it's not long till my birthday and the missus needs help in choosing a present. Which processor would you recommend?

Got today off, so iv'e taken another measurement but this time i've moved my speakers a bit and have started with the X-Over at 120Hz. Will take two more at 80Hz and 50Hz. Then will move one sub opposite it's current position and repeat.

https://i.imgur.com/hNC1MOo.jpg

Next to measurements.

https://i.imgur.com/ThtlgJS.jpg

https://i.imgur.com/R4nkGpr.jpg

This is the overlayed image of the 3 readings.

https://i.imgur.com/T2LekRX.jpg

So it looks like i should be possibly using the the 50Hz or below for my crossover? Would that be anyone else's reading of that?

[Mr.Ian]

My gut reaction is the sub phase needs to invert, but you might just have big null, winding up the sub gain and cutting the lower end might work if your power amps are good.

Personally i would look at sweeps with the subs out then the speakers out and see what they looked like before moving on. With manual eq i found it really helps if one has base infornation on each speaker

[kininigin]

My gut reaction is the sub phase needs to invert, but you might just have big null, winding up the sub gain and cutting the lower end might work if your power amps are good.

Personally i would look at sweeps with the subs out then the speakers out and see what they looked like before moving on. With manual eq i found it really helps if one has base infornation on each speaker

Well I have tried moving one of my subs around and playing with the phase ect but try as I might, I cannot get rid of the dip. I can only reduce it a bit or change where it dips. So must be in a null point. I will try your suggestions and see what is what.

I have ordered a minidsp 2 x 4HD anyway as an early birthday present. Looking forward to seeing what it can do.

[Magna Audio]

Well I have tried moving one of my subs around and playing with the phase ect but try as I might, I cannot get rid of the dip. I can only reduce it a bit or change where it dips. So must be in a null point. I will try your suggestions and see what is what.

I have ordered a minidsp 2 x 4HD anyway as an early birthday present. Looking forward to seeing what it can do.That will be interesting.
I've not used miniDSP.
Have read about them a few times.
Back in the day I went for WAF Najda 4/5 way dsp/XO/DAC.
Never looked back. I even acquired a spare one, in case anything happened to the one I'm using!