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My first speaker measurements - any advice appreciated :)

J

jamington2004

pfm Member
i started another thread about setting up a subwoofer - and the main response was too get measuring first!

So - subwoofers aside, I borrowed an UMIK1 from a kind fish. Then I watched a REW tutorial for dummies and it made feel sick. Clearly I am even lower than a dummy

Then I discovered an app called House Curve - now that’s more my cup of tea!! :)

So it appears my speakers go down to about 31hz at -3.7db. Also I have a couple of big peaks and dips in the bass probably room modes.

As I understand it’s best to leave the dips well alone as increasing those freq can make them worse. Also best to avoid eq to the whole frequency range as it can lead to a whole world of pain?

So I set the EQ Target from 40 - 100hz? And it generated a suggested response curve (B&K target) and associated 10 band PEQ file

I can load this to my Devialet amp (a recent discovery I was excited to find) but it looks a bit fiddly to tweak (remove SD card - change text file - save to SD card and insert back in amp)

So would like to see if I’m on the right track before going ahead - with some advice from you lovely sound experts out there

P.S - just getting this far I feel like some kind of hifi god all of a sudden! :) It has always been like a dark art to me - but once I ran away from REW and found an easy to use App - it’s actually quite simple :)

So here we go - first image is the response graph, second is the corrected graph from 40-100hz. Then below is suggested PEQ settings

https://share.icloud.com/photos/09c2-nd5C15hCaxA23YNhJx2Q

https://share.icloud.com/photos/0589rM_zFcGnz9bNPzc1hjPIw

Filter 1: ON PK Fc 40 Hz Gain 1.1 dB Q 1.533
Filter 2: ON PK Fc 42 Hz Gain -1.3 dB Q 10.000
Filter 3: ON PK Fc 46 Hz Gain -7.2 dB Q 6.289
Filter 4: ON PK Fc 51 Hz Gain -1.4 dB Q 10.000
Filter 5: ON PK Fc 64 Hz Gain 1.7 dB Q 4.780
Filter 6: ON PK Fc 84 Hz Gain 1.1 dB Q 8.797
Filter 7: ON PK Fc 98 Hz Gain -1.3 dB Q 10.000
Filter 8: ON PK Fc 111 Hz Gain -7.9 dB Q 4.367
 
Can the app measure left and right channels separately, if the peaks appear in both channels then they are almost certainly standing waves, measure from 20-20kHz.
Keith
 
Looks good, though no horizontal scale on your images. Looks like you have a 46Hz and 111Hz room mode - the former corresponding to 3.6m (width?) the latter to 1.5m (ceiling, though unless you are a midget it would not make sense?). Your length mode must be below 40Hz (i.e. > 4.2m?). If your speakers are going to <40, why are you only EQ from 40Hz?

Or perhaps the 111Hz is a secondary mode and your room height is 3.6m? Might be worth measuring your room and feeding it into amroc to see what is predicted. Ff your room's walls are not solid but plasterboard then your measured dimension might well be smaller than that "seen" by the sound waves.
 
@jamington2004 I see 'House Curve' is a mobile app - did you use your phone's internal microphone for this, or did you use an adaptor to connect the UMIK-1? If you used the phone's mic then the frequency response of it is going to be nowhere near flat, unlike the UMIK. I would advise you to persevere with REW and do this again - it's really not difficult to get response graphs - you plug the UMIK in, give it the calibration file if you have it, and then literally click the 'measure' button. You'll want to add some smoothing to the graph in order for it to make sense - you can do this by clicking the cog icon in the top right of the graph. 1/6 should be alright.
 
Yes J you just have to hit the ‘measure’ button on REW, adjusting the scale and smoothing can be adjusted afterwards, there is even a little camera icon which captures the entire graph.
Keith
 
jamington2004 said:
i started another thread about setting up a subwoofer - and the main response was too get measuring first!

So - subwoofers aside, I borrowed an UMIK1 from a kind fish. Then I watched a REW tutorial for dummies and it made feel sick. Clearly I am even lower than a dummy

Then I discovered an app called House Curve - now that’s more my cup of tea!! :)

So it appears my speakers go down to about 31hz at -3.7db. Also I have a couple of big peaks and dips in the bass probably room modes.

As I understand it’s best to leave the dips well alone as increasing those freq can make them worse. Also best to avoid eq to the whole frequency range as it can lead to a whole world of pain?

So I set the EQ Target from 40 - 100hz? And it generated a suggested response curve (B&K target) and associated 10 band PEQ file

I can load this to my Devialet amp (a recent discovery I was excited to find) but it looks a bit fiddly to tweak (remove SD card - change text file - save to SD card and insert back in amp)

So would like to see if I’m on the right track before going ahead - with some advice from you lovely sound experts out there

P.S - just getting this far I feel like some kind of hifi god all of a sudden! :) It has always been like a dark art to me - but once I ran away from REW and found an easy to use App - it’s actually quite simple :)

So here we go - first image is the response graph, second is the corrected graph from 40-100hz. Then below is suggested PEQ settings

https://share.icloud.com/photos/09c2-nd5C15hCaxA23YNhJx2Q

https://share.icloud.com/photos/0589rM_zFcGnz9bNPzc1hjPIw

Filter 1: ON PK Fc 40 Hz Gain 1.1 dB Q 1.533
Filter 2: ON PK Fc 42 Hz Gain -1.3 dB Q 10.000
Filter 3: ON PK Fc 46 Hz Gain -7.2 dB Q 6.289
Filter 4: ON PK Fc 51 Hz Gain -1.4 dB Q 10.000
Filter 5: ON PK Fc 64 Hz Gain 1.7 dB Q 4.780
Filter 6: ON PK Fc 84 Hz Gain 1.1 dB Q 8.797
Filter 7: ON PK Fc 98 Hz Gain -1.3 dB Q 10.000
Filter 8: ON PK Fc 111 Hz Gain -7.9 dB Q 4.367
Click to expand...

Which speaker are you showing? You should measure and EQ each speaker independently.
 
REW is as simple or as complex as you need it to be. For a presenting the amplitude frequency response from a sine wave sweep it's about as simple as you can get. I recommend persisting with REW as it's the software the majority of us on here use and it'll be easier for us to interpret the results and identify any potential errors in the measurements than if you use software we aren't familiar with.
 
I thought I had posted a response earlier but it appears not. I’d give the file a go as is, really does not matter at this stage if good or bad, just give it a go and see what you think, try to keep a note of the changes.

Before loading, refresh with a couple of familiar tracks, then load the file and listen again.

The valley around 60 Hz is more than likely a room issue, so yes, don’t boost!

(edit I did post it looks like there are two of the same threads!)
 
Thanks all for chipping in to help me out :)

It’s using the UMIK into the iPad - with its calibration file loaded to the app.

It’s measuring left and right together. I’ll try both seperately later thanks

Not sure why I did 40 - 100hz for the EQ I’ll do 20hz - 100hz. Or should I go higher than 100 I guess I should due that 111hz mode mentioned?

The photos do have a horizontal scale do you not see them? The frequencies along the bottom?

Re the room size yes that’s about right 3.6 wide by 4.2 deep - but the speakers are in a kind of recess so maybe this changes things re predicted ceiling height. At ceiling height there is like a void behind the steel support where the wall used to be (I added the partition wall set back slightly to give more space in the front room :)

https://share.icloud.com/photos/0b3PUfAJVFjv5eRFHWCLHqmDg

Thanks for confirming to not try and mess with the room mode valleys - I’ll use that amroc suggestion to see where they are to avoid them

Will REW really add much for my humble needs? I’ll persevere if so but this app seems to work well?
EDIT - just re-read the post about being able to get more help from people who can understand the REW better. So I will indeed give it a go thanks :)
 
You could also take stereo out of the equation and measure in mono, see it that makes things easier, then revert back to stereo when done with a few simple tweaks and see how it sounds?
 
jamington2004 said:
Will REW really add much for my humble needs? I’ll persevere if so but this app seems to work well?
EDIT - just re-read the post about being able to get more help from people who can understand the REW better. So I will indeed give it a go thanks :)
Click to expand...
Can you make the delineation of the horizontal axis more detailed on the app? The wide intervals (31.5Hz, 63Hz, 125Hz, etc) make it difficult to pinpoint the exact frequencies of your peaks.

Also if you could let us know how much smoothing is applied to the plot that would be helpful. In REW I like to use 1/48 smoothing when focusing on the response below 200Hz and 1/12 smoothing when looking at the overall 20Hz-20kHz response. No two program's smoothing algorithms are the same however, so 1/12 smoothing in REW may look more like 1/6 or 1/24 smoothing in your app.

You can get away with measuring both speakers together if you're only interested in what the low frequencies are doing but I don't recommend it. If you want to see how well balanced your speakers are across the spectrum then you absolutely need to take individual measurements otherwise the angle of the downward 'ski-slope' of the frequency response will be misleading due to the comb-filtering that occurs when two sound sources are playing simultaneously. Also, if your DSP allows independent EQing of left and right channels, measuring and EQing each channel individually will yield more accurate results.
 
Very pleased that you have managed to measure what is going on. Congratulations!

Keep the correction simple at first, I wouldn't correct all the little errors your app is telling to correct. -6dB at 46Hz and 111Hz should be adequate.

Add the correction into your amp and have a listen to the results.

Then try again with a "super all singing and dancing" correction that the app is telling you to do. Listen again and see which correction you like you better.
 
@ToTo Man
Got it thanks. So I see now it doesn’t have a very detailed scale so need to try and add a proper grid :)

Smoothing is set to 1/6 octave at the moment

I don’t think the devialet allows left and right EQ - just 1 text file with 10 PEQ bands

I would like to measure left and right anyway as actually if I sit dead centre of the speakers the sound appears louder from the right speaker and if I have to shift slightly to my left. Which is fine but it annoys me out of principle ;) I guess it’s because I have a door with glass on the right / pictures on the wall. And on the left a sofa with heavy cushions.

The devialet has the ability to balance the output in the settings, as well as on the fly by the remote
 
cpg said:
Very pleased that you have managed to measure what is going on. Congratulations!

Keep the correction simple at first, I wouldn't correct all the little errors your app is telling to correct. -6dB at 46Hz and 111Hz should be adequate.

Add the correction into your amp and have a listen to the results.

Then try again with a "super all singing and dancing" correction that the app is telling you to do. Listen again and see which correction you like you better.
Click to expand...

Roger that thanks!
 
Ah yes - your photos do have the scale, I had to click on the lower image to see the full image as the larger thumbnail above has clipped the image.

IMO you should continue with the iPhone method for now and see how much difference you are hearing by reducing the largest peaks. It should reduce the boominess and sound a bit tighter, you may need to increase your listening volume a touch to be better level matched.

I would also run the scan from 20 to 20k just so you get a view of what your system (i.e. electronics, speakers + room) are doing. However suggest you avoid boosting any frequencies, especially around the point where your speaker starts to tail off (it looks like from around 50Hz down, hard to say as it is masked by the room mode). Any boost in this space means you are pushing the driver too hard and it will increase distortion.

BTW your speakers are NOT capable of 31Hz at -3.7dB. That is the effect of the room mode masking the speaker. The best way you can assess the speaker capability is in an open space, another option is to close-mic the speaker to try and reduce the impact of the room mode on the measurement. Quite common for some manufacturers of small speakers to boost the bass in the 50-60-70Hz area so that it looks like the speaker can output lower frequencies.
 
Thanks. Not boosting, especially the lower freq close to the the speakers limits is a good point, and maybe why a need a subwoofer to add some weight there after all of this :)
 
ToTo Man said:
Can you make the delineation of the horizontal axis more detailed on the app? The wide intervals (31.5Hz, 63Hz, 125Hz, etc) make it difficult to pinpoint the exact frequencies of your peaks.

Also if you could let us know how much smoothing is applied to the plot that would be helpful. In REW I like to use 1/48 smoothing when focusing on the response below 200Hz and 1/12 smoothing when looking at the overall 20Hz-20kHz response. No two program's smoothing algorithms are the same however, so 1/12 smoothing in REW may look more like 1/6 or 1/24 smoothing in your app.
.
Click to expand...

Don’t seem to able to make the axis morre detailed which seems a basic miss on the app!

(Just Deleted the part I added about where the bass peaks are as was looking at a test graph on my phone - forgot the real one is on my sons (my!) iPad which is he hogging :) )

Smoothing is 1/6 octave in the pics
 
jamington2004 said:
and maybe why a need a subwoofer to add some weight there after all of this
Click to expand...
Definitely, integration is harder once you make that addition, you'll have to move to REW to do it properly as apart from frequency you need to take care of phase.

The other plus of a sub (or two) is that you can position relative to the mains to create a cancellation effect on the mode. Better than a PEQ.
 
Problem is I’m quite limited in sub positioning. The mrs already commented on the size of it hidden away in a corner ;)

This app also has a phase chart option
But I think I’ll try REW tomorrow as maybe the video I watched was unnecessarily confusing.

And after all - I am now somewhat of an expert in Room correction :) :) :)
 
Actually I just found the Devialet can accept a seperate left and right PEQ instruction :)

And it can also accept MAIN and Alternate settings - switchable via remote (off, main, alternate)

So I’ll be able to load the basic one suggested and the all singing all dancing one and toggle between
 
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