Transient test track

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Ex-Moderator
Joined 2005
Hi folks. Tom Danley was kind enough to post a very good recording he made of fireworks on his website that has some spectacular dynamics and transients.

Look at the bottom of the page for the Fireworks link.

http://www.danleysoundlabs.com/knowledge baSE.htm

I learned of this recording when I came across this thread in the Full Range forum:

http://www.diyaudio.com/forums/showthread.php?s=&threadid=83844

Just so everyone knows, the overcurrent protection on the Tripath chips really work! I had my Ref-T cut out several times while driving it hard into my speakers during the loud transients near the end of the recording.

I'm sure one of the more powerful class d modules and a good subwoofer would really bring this recording to life :)
 
wind & boom

I tried playback on my MacBook = :bigeyes: = no joy, the booms and such just plain did not come through = unable to make those tiny speakers report anything except the occasional "clicking" that sounded like a jar of crickets.

The playback througn a decent system, however !! :D ... Dramatic and almost frightening. This is a good test to see if you have any bass response at all. This is a very good test to see if your sub woofers are doing anything too.

(Got a pink noise download link?)

:smash:
 
Administrator
Joined 2004
Paid Member
Yeah, this is a good one.
Tom posted it in a horn thread over in the loudspeaker section, too.

There was a very cool test CD many years ago that had well recorded fireworks, howitzer shots, trains on tracks, that sort of thing. Very, very difficult to reproduce. I did a DAT recording of a jackhammer once. It was almost impossible to play.

These sorts of explosion tracks will show you how bad your bass really is. :( Explosions and cannon or gun shots are extremely dynamic and "Dry" or "Matte". If your bass cabinet/drivers/amp has any resonance, overshoot, decay time, etc. the shots will ring and boom. A tight bass with plenty of control will just give you a loud "TOCK", followed later by whatever reverberation was recorded from the environment.

Explosions and gunshots in the movies are always juiced up, they don't sound real - they sound "Better." Easier for must systems to reproduce. Real gunshots and explosions are very brief and dry. They only take on life if the sound bounces off something. Or the bullet does.

Don't be too discouraged by these tracks. They are extremely difficult to reproduce accurately- and very good at showing up the flaws in a system. Thanks to Tom for posting them, the really separate the men from the boys.
 
Administrator
Joined 2004
Paid Member
Below is the waveform of one of the last big Pops on the track. You can see how abrupt it is. Very hard to do clean with most speakers.

Funny thing is, the leading edge is negative - I don't know why. Mic phase, maybe?
 

Attachments

  • pop.gif
    pop.gif
    32.8 KB · Views: 141
phasing of mic

" ... the leading edge is negative - I don't know why. Mic phase, maybe? ..."

Probably correct. The mic signal may be totally inverted (like an inverting op-amp as the mic pre-amp) ...

The pressure wave from the firework is just like that of any explosive, quickly increasing pressure, followed by the dramatic lowering of pressure ... a "sign like" wave that is shown in your graph as mostly above base line, indicating some electronic or mechanical compression, possibly also induced by the microphone mechanizm.

:confused:
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.