How to: A simpler way to measure and calibrate bass without REW and mic (Online PEQ Assistant tool included)

[Sigberg Audio]

So, we (Sigberg Audio) have speakers and subs with built-in manual EQ, which is great - but we have many customers who doesn't know how to and/or doesn't want to learn how to use REW and a microphone to measure their system. Even though most here on ASR might find that to be "easy" and "worth it", many aren't as technically inclined.

After mulling over this problem for a while, I've come up with an idea of how to make it less complicated to do so. If you already have REW, this method isn't necessarily easier or even faster - but it is hopefully easier to understand and get a grip on if you don't have REW.

So what do we have:

• A Spotify playlist with sinewaves from 20-100hz in 5hz increments (
  )
• A Tidal playlist with sinewaves from 20-100hz in 5hz increments (https://tidal.com/browse/playlist/09225bdc-f6fb-43ac-897e-a6d178878fa2)
• The idea is to simply play these back through your system and measure with your smartphone. It won't be perfectly accurate, but the relative level should be accurate enough for the result to be a significant improvement over an uncalibrated system.
• I've created an excel support sheet where you can fill in the resulting sound level (SPL) of all these sinewaves for each speaker / subwoofer, and get a graph of the corresponding response.
  • It also has a section where you fill out and document the PEQ you enter into whatever EQ you have. These won't have any direct effect on the graphs.
  • After EQing, you then measure again and fill in new measurements to verify the result, which is also plotted in the graphs
  • Finally there's a separate graph that automatically plots the average of your two speakers/subs so that you can consider that when EQing, and/or use that if you have an EQ that only supports stereo EQ.
• UPDATE 2026-04-28: Now created an online tool to help assist with the PEQ: https://www.sigbergaudio.com/pages/peq-assistant

This is a very early version of it all, so I would be very interested to get some feedback and help to develop this into something people can understand before publishing it more widely. The goal isn't for this to be super sophisticated, but rather easy to use. I will of course promote it to our customers, but in theory it would work for anyone who has access to some kind of PEQ in their system, which is now more and more widely available as it is beginning to be included in streamers and DACs etc. I'll host the file and documentation on our site, and might also consider creating a web version of it (as an alternative to the excel sheet).

Questions:
Do you find this useful at all?
Do you understand how to use it?
Are the instructions clear enough?
Any other obstacles?

Online PEQ Assistant tool:

PEQ Subwoofer / Speaker calibration assistant

Configurable Online tool to help you equalize (EQ) the bass in your subwoofer or loudspeaker. Automatic Parametric EQ recommendations.

www.sigbergaudio.com

Walk-through of how to use it:

How to optimize your subwoofers for music and get tight, balanced bass in a few easy steps!

Walk-through of how to improve the bass response of your subwoofer(s) / audio system using nothing but Spotify and your phone or tablet! A simpler way to measure and calibrate bass without REW and mic (Excel sheet included)

www.sigbergaudio.no

 

[MaxwellsEq]

View attachment 376477

So, we (Sigberg Audio) have speakers and subs with built-in manual EQ, which is great - but we have many customers who doesn't know how to and/or doesn't want to learn how to use REW and a microphone to measure their system. Even though most here on ASR might find that to be "easy" and "worth it", many aren't as technically inclined.

After mulling over this problem for a while, I've come up with an idea of how to make it less complicated to do so. If you already have REW, this method isn't necessarily easier or even faster - but it is hopefully easier to understand and get a grip on if you don't have REW.

So what do we have:

• A Spotify playlist with sinewaves from 30-100hz in 5hz increments (https://open.spotify.com/playlist/2...i=ee91aea98d1a4663&nd=1&dlsi=d2a13363cea04caf)
• The idea is to simply play these back through your system and measure with your smartphone. It won't be perfectly accurate, but the relative level should be accurate enough for the result to be a significant improvement over an uncalibrated system.
• I've created an excel support sheet where you can fill in the resulting sound level (SPL) of all these sinewaves for each speaker / subwoofer, and get a graph of the corresponding response.
  • It also has a section where you fill out and document the PEQ you enter into whatever EQ you have. These won't have any direct effect on the graphs.
  • After EQing, you then measure again and fill in new measurements to verify the result, which is also plotted in the graphs
  • Finally there's a separate graph that automatically plots the average of your two speakers/subs so that you can consider that when EQing, and/or use that if you have an EQ that only supports stereo EQ.

This is a very early version of it all, so I would be very interested to get some feedback and help to develop this into something people can understand before publishing it more widely. The goal isn't for this to be super sophisticated, but rather easy to use. I will of course promote it to our customers, but in theory it would work for anyone who has access to some kind of PEQ in their system, which is now more and more widely available as it is beginning to be included in streamers and DACs etc. I'll host the file and documentation on our site, and might also consider creating a web version of it (as an alternative to the excel sheet).

Questions:
Do you find this useful at all?
Do you understand how to use it?
Are the instructions clear enough?
Any other obstacles?

The excel support document: (Please don't share this before we've stabilized this and are happy with it)

https://cdn.shopify.com/s/files/1/0284/1427/9783/files/PEQ-Sheet-SigbergAudio.xlsx?v=1718956578

Bravo! What a sensible and helpful idea. It may have been done before but I don't think I've seen it.

 

[popej]

Is a smartphone a reliable tool for measurements of low frequency? I would rather think, that low frequencies are purposely limited for voice recording.

 

[MaxwellsEq]

Is a smartphone a reliable tool for measurements of low frequency? I would rather think, that low frequencies are purposely limited for voice recording.

My experience with NIOSH on an oldish Apple phone is it is pretty good down to about 75Hz, then (compared to a professional SPL measurement device) it was about 10dB down at 30Hz.

 

[Sigberg Audio]

Is a smartphone a reliable tool for measurements of low frequency? I would rather think, that low frequencies are purposely limited for voice recording.

It doesn't have to be that reliable in absolute SPL as long as it is consistent.

I plan to test with my iphone tomorrow, and compare with a REW measurement, will report back.

EDIT: I guess I can add calculated weighting at least for iphone and ipad to the excel sheet too. A bit harder on android with so much different hardware.

 

[staticV3]

I think that a significant portion of customers who this spreadsheet and Spotify playlist was designed for, are probably iPhone users.

If they use an iPhone, they could just use the HouseCurve App and get better results that way, in part due to its mic calibration, no?

 

[Sigberg Audio]

I think that a significant portion of customers who this spreadsheet and Spotify playlist was designed for, are probably iPhone users.

If they use an iPhone, they could just use the HouseCurve App and get better results that way, in part due to its mic calibration, no?

Wasn't familiar with that app, and that sure seems that it should be able to solve the same problem. I did however test it now, and for me specifically I couldn't get it to work, so then I am a bit worried about the user experience again. I got it to connect via bluetooth and it sent a test signal, but it failed to detect/read it and I could not get a measurement recorded in the app. So was unable to test further.

 

[Sigberg Audio]

Did a quick test with the excel sheet and an iphone now, comparing it with REW. Certainly seems to be accurate enough for simple EQ adjustments.

I obviously have awesome subwoofers and listening room, so it was pretty good to begin with, but still proves the point.

This is a single sub measured in the listening position.

Rew measurements (before and after EQ):

The same entered manually into the excel document based on measurements with Spotify sine waves + iphone:

Doing this manually in 5hz increments is of course not as accurate as REW, and the EQ filters I added I also did based on my measurements with the excel document rather than REW, so those are not ultra precise either. But still more than decent, and sounds good.

Looks like the iphone falls off harder than reality from 30hz and down, but that's fine for our purpose.

 

[Sigberg Audio]

I've now written a walk-through using a real example to make it even more clear how to use this in practice:

https://www.sigbergaudio.com/blogs/...music-tight-balanced-bass-in-a-few-easy-steps

 

[Tom C]

Did a quick test with the excel sheet and an iphone now, comparing it with REW. Certainly seems to be accurate enough for simple EQ adjustments.

I obviously have awesome subwoofers and listening room, so it was pretty good to begin with, but still proves the point.

This is a single sub measured in the listening position.

Rew measurements (before and after EQ):
View attachment 376508


The same entered manually into the excel document based on measurements with Spotify sine waves + iphone:
View attachment 376509

Doing this manually in 5hz increments is of course not as accurate as REW, and the EQ filters I added I also did based on my measurements with the excel document rather than REW, so those are not ultra precise either. But still more than decent, and sounds good.

Looks like the iphone falls off harder than reality from 30hz and down, but that's fine for our purpose.

Is the 9dB rolloff from 20Hz to 30Hz not a practical issue?

 

[Sigberg Audio]

Is the 9dB rolloff from 20Hz to 30Hz not a practical issue?

I don't think it is for the sake of EQ. I used an app without mic compensation, but apps that have that exist as well. But the main goal here is to EQ the system rather than get perfect information about low-end roll off. You'll typically not be EQing a lot below 30hz.

But possible improvements could be

A) More clearly inform that the results below 30hz is probably not accurate (will fix that)
B) Add automatic weighting in the excel sheet (will consider that).

 

[Grotti]

I am not at home right now but I will give it a try in the next two weeks. Great idea, btw...

 

[Sigberg Audio]

A guy brought up the fact that even if you don't have EQ, this can be useful to just measure the response in your room, and also while testing different positions either for the components or your own listening position.

 

[DavidMcRoy]

I’ve long used pink noise for measurements and have just begun playing with House Curve. I do like the results with its compensation for my iPhone 12 Pro Max and iPad Air 2 built-in mics, and I want to try it with my UMIK-1, etc. mics that have inherently better low end accuracy, as well. The spot sine waves in this protocol are a good idea, too. I’ve read anecdotally that there’s “no difference” in results from pink noise vs. tones, but we’ll see if there is any significant and unreconcilable difference.

 

[Sigberg Audio]

I’ve long used pink noise for measurements and have just begun playing with House Curve. I do like the results with its compensation for my iPhone 12 Pro Max and iPad Air 2 built-in mics, and I want to try it with my UMIK-1, etc. mics that have inherently better low end accuracy, as well. The spot sine waves in this protocol are a good idea, too. I’ve read anecdotally that there’s “no difference” in results from pink noise vs. tones, but we’ll see if there is any significant and unreconcilable difference.

I think there are several approaches that can give you good results. So this is more about offering an alternative that may be perceived as easier to do by those who are perhaps less technically inclined. Not that the method or results is in itself superior to the alternatives.

 

[Sigberg Audio]

Tidal playlist (with sine tones) added:

Sigberg Audio Bass calibration playlist

Playlist - Sigberg Audio Bass calibration playlist - 17 items

tidal.com

 

[Sigberg Audio]

I've converted this into a webpage now, that actually suggests PEQ adjustments. It also shows an estimate of the new response after the PEQ adjustments.

It intentionally does not suggest very agressive EQ to maintain some life and natural bass rather than EQ entirely flat. You can also adjust how agressive it is, by adjusting how high a peak has to be before it takes it into account, and how aggressively it tries to flatten it.

And you can choose to adjust / correct for two individual speakers/subs or the average of both. The average will be a somewhat approximate thing of course.

It's a bit cumbersome but pretty simple to use. Basically enter the measured bass response from 20-100hz in 5hz increments, either for one or two speakers/subwoofers. Then it analyses and suggests EQ adjustments + plots an estimated new response. You can also have it analyze an average of the two.

The target audience for something like this is those who do not have advanced measurements equipement or REW, but just manually plot the dB level at each frequency and are unsure what to adjust to get a decent response.

PEQ Subwoofer / Speaker calibration assistant

Configurable Online tool to help you equalize (EQ) the bass in your subwoofer or loudspeaker. Automatic Parametric EQ recommendations.

www.sigbergaudio.com

 

[Sigberg Audio]

Further improved this.

• Graph is now smoothed
• Both the visual graph and Q calculations are now logaritmic
• It's now possible to save the data so you can continue later in the same browser
• The EQ suggestions can now be edited, and you can even add your own manual PEQ, and the estimated response graph will update accordingly. This allows you to experiment with the EQ and see the result in real time.

PEQ Subwoofer / Speaker calibration assistant

Configurable Online tool to help you equalize (EQ) the bass in your subwoofer or loudspeaker. Automatic Parametric EQ recommendations.

www.sigbergaudio.com