Head-Fi.org › Forums › Equipment Forums › Sound Science › Relatively cheap headphone measuring kit?
New Posts  All Forums:Forum Nav:

Relatively cheap headphone measuring kit?

post #1 of 7
Thread Starter 

I have quite a few rare (and common) headphones so I'd like a measuring system to assist in benchmarking their performance, without having to send them out to Tyll or someone else to test them for me.

 

A couple of members I know use REW V5 to do this but I don't know what other software is available, nor what microphones and/or dummy heads are available, etc. My searches on google have been baiscally fruitless so I thought it wouldn't hurt to ask here.

 

Thanks.

post #2 of 7

For relatively cheap kit you'll be looking at,

 

 

 

Here are a couple of threads which might be of some help:
http://www.head-fi.org/t/482386/building-a-headphone-measurement-lab

http://www.head-fi.org/t/636885/headphone-testing-to-pinna-or-not-to-pinna-that-is-the-question

post #3 of 7

What parameters of the headphones do you intend to measure exactly ? If you are using utilities from my package, I could post a detailed description of how to measure any of the following:

- frequency response using MLS

- frequency response using sine sweep

- THD vs. frequency

- THD vs. level

- impulse response from MLS

- group delay vs. frequency from impulse response

- CSD from impulse response

- impedance/phase vs. frequency

post #4 of 7
Thread Starter 
Quote:
Originally Posted by stv014 View Post

What parameters of the headphones do you intend to measure exactly ? If you are using utilities from my package, I could post a detailed description of how to measure any of the following:

- frequency response using MLS

- frequency response using sine sweep

- THD vs. frequency

- THD vs. level

- impulse response from MLS

- group delay vs. frequency from impulse response

- CSD from impulse response

- impedance/phase vs. frequency

I was planning on doing a FR with a sine sweep, two square waves at 30 and 300 Hz, and a CSD plot. 

post #5 of 7
Quote:
Originally Posted by takato14 View Post

I was planning on doing a FR with a sine sweep, two square waves at 30 and 300 Hz, and a CSD plot. 

 

I made a post recently that outlined some of the measurement rigs from which graphs and data are routinely posted here. Here's the link: Headphone Measurements

post #6 of 7
Quote:
Originally Posted by takato14 View Post

I was planning on doing a FR with a sine sweep, two square waves at 30 and 300 Hz, and a CSD plot. 

 

Actually, all of those (FR, square wave response, CSD) can be derived from the impulse response if you ignore non-linear distortion (which, with good headphones, is probably only a potential issue for the 30 Hz square wave at high SPL). Of course, it is easy to generate actual square waves, record them, and view the waveform in an audio editor. Using a sine sweep for frequency response testing has the advantage that it also gives a THD vs. frequency graph.

 

To measure the impulse response, you need an MLS signal, which you can generate with my 'testgen' utility, for example:

 

mls 0 25 1000010000000100010 0.3 0.3

 

This example works best at 48 or 44.1 kHz sample rate. You can actually delete the first few (<10) seconds of the resulting WAV file, because it will not be used in the impulse response output. The following command extracts the impulse response:

 

convolve.exe mls.wav ir.wav -inv=1 1000010000000100010

 

The second impulse - which will also have the highest amplitude if you truncate the beginning of the test signal - in the output file is the impulse response, you can use any audio editor to remove the unneeded parts of the file. To get a correct frequency response above 1-2 kHz, the recorded audio also needs to be equalized (this is not easy to get right with a DIY artificial ear). Note that the above command for "decoding" the MLS only works correctly if the original and the recorded file have exactly the same sample rate; that is, the DAC and ADC in the test setup should preferably be on the same physical device and share the same clock, otherwise pitch correction may need to be applied to the file.

 

The FR can be displayed with a simple FFT analysis of the impulse response. You can also convolve square waves with the IR to get the square wave response, if you did not record any actual square waves. For CSD analysis, you can use my 'csd' utility (I will explain the details of the usage and parameters later), or other programs.


Edited by stv014 - 5/24/13 at 12:23pm
post #7 of 7
Quote:
Originally Posted by takato14 View Post

I have quite a few rare (and common) headphones so I'd like a measuring system to assist in benchmarking their performance, without having to send them out to Tyll or someone else to test them for me.

 

A couple of members I know use REW V5 to do this but I don't know what other software is available, nor what microphones and/or dummy heads are available, etc. My searches on google have been baiscally fruitless so I thought it wouldn't hurt to ask here.

 

Thanks.

 

For mic I use an EMM-6 which Anetode recommended above.

 

For USB audio interface I use a Focusrite 2i2: 

http://www.bhphotovideo.com/c/product/822508-REG/Focusrite_SCARLETT_2I2_USB_Scarlett_2i2_Portable.html

New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Sound Science
Head-Fi.org › Forums › Equipment Forums › Sound Science › Relatively cheap headphone measuring kit?