Certainly no one seems to have located one in the wild. I can understand that John may need to capture little chirps of something happening and if music and our ears were able to deal with it so should our audio systems.
In terms of 'got bass?' I remembered this clip YouTube which hopefully isn't uk locked where they wanted to get alligators to show their infrasonic mating bellows so rolled out a couple of ET fan subs. Apparantly some crocs can make sound under 10Hz. I don't want to get close enough to a horny male croc to find out if I can hear it!
For the record, the low freq response with 30ips can be fixed. Here is an example.
Secondly, often ultrasonic bandwidth is rolled off to improve MEASURED NOISE specs, or to compensate for reproduce head losses due to scanning (at low frequencies) or from lamination thickness. At 30ips, scanning is not a problem, 2mil lam heads are quieter than 6mil, like Ampex used in the 60's. It took a decade from when I pointed this out (1968) to the Ampex audio department to when they improved the heads with 2mil laminations. Much of the head noise is ultrasonic, so rolling off might be thought useful.
It is NOT the frequency response that is so important, it is the RISE-TIME of the recorded signal that is.
Secondly, often ultrasonic bandwidth is rolled off to improve MEASURED NOISE specs, or to compensate for reproduce head losses due to scanning (at low frequencies) or from lamination thickness. At 30ips, scanning is not a problem, 2mil lam heads are quieter than 6mil, like Ampex used in the 60's. It took a decade from when I pointed this out (1968) to the Ampex audio department to when they improved the heads with 2mil laminations. Much of the head noise is ultrasonic, so rolling off might be thought useful.
It is NOT the frequency response that is so important, it is the RISE-TIME of the recorded signal that is.
Attachments
Wait, I thought you collected the data before making a bold statement. I forgot for a second of the "design-by-ear" methodology you are so keen of, how naive of me.
looks like lots of 20k and nothing to filter till 24k. ie a brickwall should retrieve a decent 20k sine.
The microphones used for the GD Wall of Sound vocals didn't need the ultrasonic capability, but did need their capsules to be small and well exposed. They were used in pairs, wired out of polarity to reject the sound from the PA only meters away. The Wall of Sound used no floor kicks for foldback - the band got the same sound as the foh - so the mics had to reject the flattish-field PA sound but accept the nearer vocal sound.
All good fortune,
Chris
All good fortune,
Chris
Sure to make it directional, like most live gig mics, wonder what that did to the BW? Like it maters with a PA that dosnt go above 20k
What specification of the amplifier? It is low THD at 20kHz? Low IMD?
What specification of the speaker? It is low THD at high frequency?
If the distortion at high frequency is not low enough, it is better to filter it.
Probably had to roll off the top pretty hard, because the cancelling trick only works if the two mics are close compared to a wavelength. These were only used for a few years, and had been retired by the time I finally got to see the GD, 1981 (?). Recordings from the era can sound fine or weird, depending on your personal headspace.
More importantly, I think, the Wall of Sound put the band and the crowd in the same soundfield. Also, the band wasn't mixed down to a mono foh. Each performer had their own giant stack of speakers, right behind them.
All good fortune,
Chris
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Nah. You attacked him mercilessly because he is John Curl and you hate what he promotes.
He provided data on mikes that were used for specific applications. He didn't say anything to provoke your idiotic attack.(sorry, but you crossed the line).
He may be on the nose w/r to bw and sound..he may not. But I would hope for civility.
Jn
LTSpice can very well create a 44.1/16 .wav file like you did, but is not the right tool tool to analyse the spectrum of this file, because it connects all datapoints with straight lines instead of ZOH.
This alters the Frequency content and shows a wrong spectrum.
Better to use a tool like RMAA to analyse the spectrum of the created .wav file.
Hans
I had problems with my ATR100 ceramic heads.
The ceramic was crumbling on the edge of the gap. It was worse at 30IPS (heat ?). I gave-it up with 30IPS.
Well, it is a weee tiny bit more than arm chair opinion.
Fine. You are entitled to your opinion also. Then listen to JN.
THx-RNMarsh
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