Audio Level Meter
For accurate RECORDING.
I designed these audio level meter programs to allow the optimum setting of input levels for various sound recording functions, particularly for video editing. When capturing video and sound from different sources accurate level setting helps maintain a consistency of volume across various clips, and therefore eases the sound mixing.
IT DOES NOT INDICATE PLAYBACK OUTPUT LEVELS. There is no way I know to access the output from another program. This meter indicates only what is fed into the wave input channel.
To monitor playback output levels feed the wave output back into the wave input, either externally with a cable or by using the Windows Mixer if you have this option. My meters can be very useful operated in this way but for accurate work you would need to calibrate it. As an aid to calibration here is a Calibration Tone Wave File you can download. This is recorded at a level 4dB below Full Scale Digital. Playback this file and set up the meter so this reads '6' or +8dB on the scale, or just at the start of the red. Or whatever you like!
Requirements: A soundcard capable of 44.1KHz 16 bit stereo sampling is required. Windows XP or Vista recommended. In Windows XP it is possible to have dozens of instances of the Level Meter running simultaneously if one was mad enough. The processor load is very small.
Installation. Simply copy any of the versions to any directory you like and create a shortcut to it.
Accessing the Options. Right-click over the background area to call up the Options and About screen. Peak Hold optionally holds the maximum peaks. To reset, click the small button or click anywhere on the background area. Turn on or off from the Options screen. Other options include having a yellow middle segment and to keep the meter always on top.
Calibration. 0dB on the VU-style meter could be set to represent the absolute maximum the system can handle, the so-called FSD or full-scale-digital. There is no scale above 0 because in a digital system there is no more! Some soundcards limit before hitting the theoretical full scale output of a 16 bit ADC. In any case it is unnecessary and unwise to push the soundcard to it's absolute limit. Stay out of the red to leave a bit of headroom. (The PPM is normally set up with more headroom.)
If you find the meter doesn't seem to peak high enough, or you get distortion you may have to adjust the sensitivity. See Adjusting the Calibration for more details.
A word about Sample Rate.
This program samples at 44.1KHz 16 bit stereo. I'm often asked for a version which works at 48KHz. It is not necessary. The PPM program works independently of the program you use for recording, you may use any sample-rate you wish. 44.1KHz is more than adequate for metering. More unknown is the use of my program together with recording in 24 bit sampling. If anyone has any experience please let me know.
Use of this program is free and unrestricted. However, if you find my program useful please consider making a small contribution via PayPal. If you'd rather - cheques or cash are just as acceptable. My address on request.
Watch this space - new versions or enhancements may appear.
Peak Programme Meter Version 1.6
Example set-ups
PPM features:
Mono matrix can be set to M = (A+B) - 3dB or 6dB. Traditionally the BBC have used M3, though M6 is increasingly used.
Channels can be labelled L & R or A & B.
Displays Left, Right, Mono (sum) and Stereo (difference) simultaneously.
Ballistics are more accurately modelled. The fallback time from 1 to 7 is now in line with BBC specifications, 2.5 to 3 seconds. However, at the present time, the attack time (eg 2.5dB down for a 10ms burst) is not. Peaks as short as 1ms register accurately.
I prefer a faster fallback, especially as there are the peak markers, so the fallback time can be adjusted by means of an arbitrary value entered on the options page. A value of 2 corresponds to the BBC PPM spec. Values up to 10 speed up the decay.
There is also a 20dB button. This increases the gain of of the Stereo difference indication by 20dB (10 times). M, L & R are not affected.
The colour of each bar can be set to any colour from the options screen. By default all bars are green but now it possible to have, for example, red and green for A and B.
Clicking on the small button bottom-left closes the Mono & Stereo display for those where only Left & Right is wanted. My old single PPM version has been discontinued.
The settings can be locked. Tick the 'Lock Settings' box and enter a password which will allow un-locking. To unlock, enter the password text and un-tick the 'Lock Settings' box (don't press return). This is not high security - the password can be found in the registry.
Can work in 640x480 for a giant size display!
NB The 'over' indication lights at Full Scale Digital - 1.5dB regardless of calibration. Some soundcards may not reach this level. Let me know if this is a problem
Download PPM.exe version 1.6 (zipped 218K)
Use of this program is free and unrestricted. However, if you find my program useful please consider making a small contribution via PayPal.
'Analogue' Peak Programme Meter
In response to several requests for an analogue-style PPM along the lines of the BBC ME12/9 here is my version, presented as much for nostalgia as for usefulness!
Not quite as smooth as the real thing, but more or less conforms to the attack and decay spec.
Unlike my other PPM and VU meters which read any peak no matter how short, this one approximately conforms to the spec which states that for a 5kHz tone burst:
Fallback time: 2.5 - 3.0 secs fall from 7 to 1.
To operate the Post Office lever key switch click on the graphic right, centre or left. If you don't want to switch to mono/stereo mode the window can be closed down to obscure the switch. As usual, right click to access the options.
There is also an 'Over' Led which can be set to a level of the users choice. This operates in the digital domain so is not subject to the needle ballistics and may indicate very short transients.
Some comments from users:
" ...I've compared your PPMs to hardware ones, and they're so close as to be considered identical." AC
" - by far the best displays I have ever seen for a PC screen - and very accurate too." AR
"Congratulations on your level meters, they really are stunning and as an ex BBC local radio presenter / tech op very nostalgic." GL
"Let me tell you the ppm1.42 and the others from you is my favorite vu meter for a long time. It looks like very fine and working very good without crashes on every system!" RS
"I'm just trying out your 'Analogue' PPMs, and am really impressed!" MP
"I used your PPM to set levels on playbacks into the last series of Doctor Who. If you saw the 'Weakest Link' and 'What not to wear' sequences then that was your software plus a great play-in program called Soundplant." NH
"Everyone I show your meters to absolutely loves them!" AC
“Viewing it alongside both REAL Sifam meters, RTW Vectorscope & a Chromatec display I must say it looks perfect.” - RH
"Your meters are great. Is there a version for the MAC?" - Sorry, No.
Download PPM_analogue.exe version 1.41 (zipped 235K)
The large PPM is approximately life size. As this is may be a bit large here is a smaller version. Click the push button to switch to M/S mode. There is no 20db boost button .If you don't want to switch to mono/stereo mode the window can be closed down to obscure the switch. As usual, right click to access the options. When the switch is obscured you can still change modes by double-clicking on the window.
There is no title bar on this version. You can move it by dragging anywhere on the window. To exit use the taskbar menu.
Download PPM mini.exe version 1.3 (zipped 223K)
New Version! June 2006. Displays A, B, M and S simultaneously.
The 'Over' Led can be set to a level of the users choice. This operates in the digital domain so is not subject to the needle ballistics and may indicate very short transients.
Resizeable. From the settings screen (right-click), enter the width you require in pixels from a really tiny but fully formed 100 pixels wide up to a monster 800 pixels wide. Click OK to save the changes and then restart for the new size to take effect.
Download PPM Quad.exe Version 1.1 (zipped 228K)
... and then there is this twin left & right version. There is no title bar on this version. You can move it by dragging anywhere on the window, and to exit use the taskbar menu. Double-clicking reveals a button for MS mode.
Resizeable. From the settings screen (right-click) to enter the width you require in pixels from a really tiny but fully formed 100 pixels wide up to a monster 800 pixels wide. Click OK to save the changes and then restart for the new size to take effect.
Also in this version a small change to the 'over' indication. It no longer follows the PPM attack time but is instantaneous (at -1.0 dB FSD as before)
Download PPM twin.exe version 1.4 (zipped 228K)
VU - type scale (but still reads peaks!)
This is my first attempt at creating accurate meters. Essentially unchanged from Windows 95 through to XP.
Download meterH.exe For Win95/98/ME/NT/2000/XP (330K)
Download meterH.exe
For Win95/98/ME/NT/2000/XP (330K)
If you prefer there is this vertical version. This is a different program file - I couldn't be bothered to make it switchable!
Download meterV.exe For Win95/98/ME/NT/2000/XP (330K)
Download meterV.exe
Download both meters together zipped (345K)
Version History
1.3 - 16/1/2001 - At the request of users, Version 1.3 adds an (optional) yellow middle segment and an optional 'Always on Top' feature. To access the options click the right mouse button over the background area. I know this is unconventional - I want a clean display uncluttered by buttons and menus.
1.4 - 25/1/2001 - Horizontal version of above.
1.5VN - 10/9/2001 - Slimline vertical version created at users request. Stores last screen position on exit.
1.5H - 7/3/2002 - Slimline horizontal version created at users requested. Dropped the old larger versions. Tested under Windows XP and no changes necessary.
1.6V and 1.6H - Peak Hold feature added at request of several users. Reset by a small button, or just by clicking anywhere on the background. Switchable from the Options screen (right click to access)
PPM V1.0 created 4/8/2003 - Non-linear scale algorithm added. Other scaling now easily possible.
[still to do - add extra features of PPM Dual to basic PPM.]
PPM Dual V1.0 created 10/10/2003 - Simultaneous L,R,M & S displays. 'Always on top' fixed.
PPM V1.1 created 12/1/2004 - M3 or M6 switchable.
PPM Dual V1.2 created 13/2/2004 - Bars can be set to any colour.
PPM V1.3 Dual version now called just PPM - old single version dropped. M-S can be closed off. Now works 640x480 properly.
PPM V1.4 Password-protected 'Lock Settings' added. 'Always on top' fixed (always was on top!)
PPM V1.41 Fixed - Decay value now stored correctly. PPM V1.42 'db' changed to 'dB'.
PPM V1.5 Out-of-phase Mono handled correctly
PPM V1.6 - PPM Analog V1.4 - PPM Mini V1.3 - PPM Quad V1.1 - PPM Twin V1.4 Calibration accepts decimal values : PPM Analog V1.4 - Title Bar removed 21/8/6
© Paul Marshall 2001