Testing Frequency Response with an Android Phone

[spaceman5]

Hi


I have an Android smartphone, with Android v8.0.

I would like to test my audio system, and generate a FR graph.

What app is recommended to use, for Android?


Also,
should I trust the built-in microphone?
Or buy something external?
My phone has OTG, so I can connect an external USB Microphone
(Mic+ADC+USB Controller, thus not basing the test on the phone's Mic or ADC)


Thank you

 

[DF96]

If you use a microphone you are testing the frequency response of the microphone and the room and the speaker and the amplifier. Which of these do you actually want to test?

 

[spaceman5]

Speakers+Room 🙂

Ideally, the microphone would have as less effect on the result as possible..

 

[scottjoplin]

The first post here may be useful, it includes links to other similar threads Best free/cheap apps for diy audio 2018

 

[Speedysteve7]

I typically use a measuring mic that I sent away to be calibrated and a phantom mic amp / Holmimpulse on my laptop.
If I look for a peak in the measurement and then level it in DSP (Najda) I can see it's levelled and hear the difference.

I tried the same thing on my phone (Google Pixel Android 9 - not that this would make any difference really) measuring, I see pretty much the same peaks and troughs.
I've not tried tuning the bass frequencies solely with my phone yet though 🙂

 

[spaceman5]

The first post here may be useful, it includes links to other similar threads Best free/cheap apps for diy audio 2018

Looks great, thank you very much!

I typically use a measuring mic that I sent away to be calibrated and a phantom mic amp / Holmimpulse on my laptop.
If I look for a peak in the measurement and then level it in DSP (Najda) I can see it's levelled and hear the difference.

I tried the same thing on my phone (Google Pixel Android 9 - not that this would make any difference really) measuring, I see pretty much the same peaks and troughs.
I've not tried tuning the bass frequencies solely with my phone yet though 🙂

Interesting, so switching to phone did not have much difference..
Nice to hear.
(obviously it will change from phone to phone, depending on the components' quality..)

 

[Speedysteve7]

I use the Advanced Spectrum Analyzer Pro (spectrum analysis) app.

I think you could get quite far with this for basic measurements and correction.

Holmimpulse and similar generates sweep tones so no need to play test tones some other way and can do time alignment etc etc too of course.

 

[spaceman5]

Thank you very much Speedysteve7.
Advanced Spectrum Analyzer Pro is also the first recommended app on the forum thread scottjoplin linked to. So it seems to be favored by many. Will install it this evening.

The purpose is to test my system, which is a computer with a DAC and 2 HS7 monitors.

Do I need to play some .WAV file on my PC?
(or run some program on it, that will generate the sound to be picked up by the phone+app?)

 

[Pano]

I use a calibrated mic I got from Parts Express along with the "Audio Tools" suite on the iPhone. Should be apps that work just as well on Android.
Dayton Audio iMM-6 Calibrated Measurement Microphone for Tablets iPhone iPad and Android
AudioTools | Studio Six Digital

 

[baeijsman]

Some phones (I have seen this on Sony) have some sort of fixed internal filtering of the mic, but this should be pretty obvious when you look at the curves.

 

[Speedysteve7]

I've not used these but could be a good start..

Audio Test Tones by Audiolab on Spotify

Here are lots of bass test tones

Frequency Bass Test Tones 5HZ-100HZ on Spotify

Try them on your system and see what the phone app says.

 

[spaceman5]

I use a calibrated mic I got from Parts Express along with the "Audio Tools" suite on the iPhone. Should be apps that work just as well on Android.
Dayton Audio iMM-6 Calibrated Measurement Microphone for Tablets iPhone iPad and Android
AudioTools | Studio Six Digital

Thank you Pano.
I wanted to buy that microphone from PE long ago,
yet I wonder why Parts Express did not make a USB one, that includes a built-in ADC..

Their current microphone depends on each phone's ADC, meaning results may vary a bit according to the quality of the ADC one got in his phone.
Including the ADC in the Mic, like in a USB Mic, would solve that, yet they did not release a product like that..

Some phones (I have seen this on Sony) have some sort of fixed internal filtering of the mic, but this should be pretty obvious when you look at the curves.

I have Sony Xperia 🙂

I've not used these but could be a good start..
Audio Test Tones by Audiolab on Spotify

Here are lots of bass test tones
Frequency Bass Test Tones 5HZ-100HZ on Spotify

Try them on your system and see what the phone app says.

Thank you very much

 

[spaceman5]

A small update..

I wrote in the previous post

I wonder why Parts Express did not make a USB one, that includes a built-in ADC..

Their current microphone depends on each phone's ADC, meaning results may vary a bit according to the quality of the ADC one got in his phone.
Including the ADC in the Mic, like in a USB Mic, would solve that, yet they did not release a product like that..

It seems they did release one:

Dayton Audio UMM-6 USB Measurement Microphone

Not exactly cheap tho, 75$

 

[Speedysteve7]

I tried the test tones from Spotify and the phone app.
Very accurate (surprisingly so in fact) above 100Hz or so and up to about 12KHz.
Not so good outside of that.
All down to the phone's mic I guess.
It was never designed with this in mind..
Might be a lot better with a plug in mic?

I won't be using my phone to set my system's tapped horns up 😉

 

[trobbins]

It would be interesting if any apps came with a calibration process, then the level inadequacies of the phone mic can be nulled out probably to beyond say 30-15kHz - that would make a very handy instrument.

A removeable muff or directional windscreen could come in handy for some measurements.