To follow this tutorial you will need the following:
A suitable soundcard must have 'phantom power' which is the ability to power the microphone connected to it. It must also have reasonably low noise and distortion. Such a soundcard can be had for about £150. A few examples:
Focusrite Saffire 6
M-Audio Fast Track Mobile
Tascam US-122
Presonus AudioBox
A suitable microphone is usually quite expensive costing a couple of hundred pounds. There is one exception and that is the ubiquitous Behringer ECM8000: Behringer ECM8000
ARTA is a software package that has full functionality, except saving files, free of charge: ARTA Download
ARTA will generate a test signal on the soundcards outputs and record whatever appears at the soundcards inputs. You can then analyse the recorded signal. In this case we want to output the test signal to the hi-fi and record the room and speakers via the microphone, then look at the frequency response.
This is what I am using:
M-Audio Fast Track Ultra
Beyer Dynamic MM1 Microphone
Samsung Laptop
Jack to RCA cables X2
XLR to XLR microphone cable
So lets get started. You have your hi-fi set-up (I've setup mine in my work room for this tutorial).
Now you need to connect up your hardware. Plug your soundcard outputs into your hi-fi and select the inputs you are using so that any sound from the computer will go to the speakers.
Now connect your microphone to the left input of your soundcard and make sure you have phantom power enabled.
Place the microphone at your listening position around head height. I have a mic stand so this is quite easy. If you don't, you can either balance it on some cushions or ask a friend to hold it very still.
The mic doesn't need to be placed directly pointing at the speakers because it is omni-directional. Common practice is to have it pointing upwards. In this case don't be surprised to see the high frequencies rolling down above about 8KHz.
I trust you have already installed ARTA, which is as simple as clicking next, next, next... So run the ARTA main program.
Click the little microphone icon to access Audio Devices Setup. Make sure you have your soundcard selected as the output device in the top drop down list, and if the option is there use ASIO drivers. Make sure the correct input and output channels are selected. Click Okay.
Click the red record icon to access the recoding window. You should set the longest sequence length for the best signal to noise ratio. Sampling rate is okay at 44.1KHz and higher is not really necessary here. Set the correct input channel for your microphone. Disable dual channel measurement mode. Finally set 2 averages, this helps further reduce noise from traffic outside and such.
Click on the generate button to test the levels. You can see the level meters at the bottom of the window, one of which should be unused. Adjust the amp volume until the test noise is about as loud as you can bare comfortably. You want to get the signal level as much above ambient noise as you can for accurate results. Adjust the microphone input level on the soundcard to make sure it is near the top of the level meter, but not clipping.
When the level is correct stop the generate function. Now click on the record button. The system will output the test signal and record the input. The record window should then close and show the recorded 'impulse response'.
In the main window showing the impulse response, click the left mouse button just before the beginning of the waveforms sharp rise. This sets the beginning of the area to be analysed; the beginning of the 'gate'.
Use the zoom buttons on the right-hand side to zoom out, and then use the right mouse button to place the end marker of the area to be analysed. If you look at the bottom of the window you will see some text that says Cursor and Gate. The Gate part should read about 3000-3500.
Once these markers are set you can analyse the frequency response by clicking on the FR icon.
If you are running the un-licensed version you can't save this data, however you can copy the graph to the clipboard to be pasted into an image editor and saved.
A computer (near your hi-fi)
- A sound card (one that can accept phantom powered microphone inputs)
- A measurement microphone (omni-directional with flat response)
- Some cables to connect the soundcard output to your hi-fi and the mic to your soundcard
- ARTA measurement software
A suitable soundcard must have 'phantom power' which is the ability to power the microphone connected to it. It must also have reasonably low noise and distortion. Such a soundcard can be had for about £150. A few examples:
Focusrite Saffire 6
M-Audio Fast Track Mobile
Tascam US-122
Presonus AudioBox
A suitable microphone is usually quite expensive costing a couple of hundred pounds. There is one exception and that is the ubiquitous Behringer ECM8000: Behringer ECM8000
ARTA is a software package that has full functionality, except saving files, free of charge: ARTA Download
ARTA will generate a test signal on the soundcards outputs and record whatever appears at the soundcards inputs. You can then analyse the recorded signal. In this case we want to output the test signal to the hi-fi and record the room and speakers via the microphone, then look at the frequency response.
This is what I am using:
M-Audio Fast Track Ultra
Beyer Dynamic MM1 Microphone
Samsung Laptop
Jack to RCA cables X2
XLR to XLR microphone cable
So lets get started. You have your hi-fi set-up (I've setup mine in my work room for this tutorial).
Now you need to connect up your hardware. Plug your soundcard outputs into your hi-fi and select the inputs you are using so that any sound from the computer will go to the speakers.
Now connect your microphone to the left input of your soundcard and make sure you have phantom power enabled.
Place the microphone at your listening position around head height. I have a mic stand so this is quite easy. If you don't, you can either balance it on some cushions or ask a friend to hold it very still.
The mic doesn't need to be placed directly pointing at the speakers because it is omni-directional. Common practice is to have it pointing upwards. In this case don't be surprised to see the high frequencies rolling down above about 8KHz.
I trust you have already installed ARTA, which is as simple as clicking next, next, next... So run the ARTA main program.
Click the little microphone icon to access Audio Devices Setup. Make sure you have your soundcard selected as the output device in the top drop down list, and if the option is there use ASIO drivers. Make sure the correct input and output channels are selected. Click Okay.
Click the red record icon to access the recoding window. You should set the longest sequence length for the best signal to noise ratio. Sampling rate is okay at 44.1KHz and higher is not really necessary here. Set the correct input channel for your microphone. Disable dual channel measurement mode. Finally set 2 averages, this helps further reduce noise from traffic outside and such.
Click on the generate button to test the levels. You can see the level meters at the bottom of the window, one of which should be unused. Adjust the amp volume until the test noise is about as loud as you can bare comfortably. You want to get the signal level as much above ambient noise as you can for accurate results. Adjust the microphone input level on the soundcard to make sure it is near the top of the level meter, but not clipping.
When the level is correct stop the generate function. Now click on the record button. The system will output the test signal and record the input. The record window should then close and show the recorded 'impulse response'.
In the main window showing the impulse response, click the left mouse button just before the beginning of the waveforms sharp rise. This sets the beginning of the area to be analysed; the beginning of the 'gate'.
Use the zoom buttons on the right-hand side to zoom out, and then use the right mouse button to place the end marker of the area to be analysed. If you look at the bottom of the window you will see some text that says Cursor and Gate. The Gate part should read about 3000-3500.
Once these markers are set you can analyse the frequency response by clicking on the FR icon.
If you are running the un-licensed version you can't save this data, however you can copy the graph to the clipboard to be pasted into an image editor and saved.
