thanks for this useful and intriguing info. You have piqued my interests in pipes! And thanks everyone else too.
Sans experiencing the pipe organ you describe in detail, do you (or anyone else for that matter) have any reference CD material (or SACD) which would provide a good variety of subsonic information? I have recently bought "The Great Fantasy Adventure Album" (Erich Kunzel - Cincinati Pops Orchestra, CD-80342 - Telarc) which does have some information around 5Hz in "Jurassic Park" and "T. Rex", but it is a bit short in duration.
For the purposes of the Linux/Alsa investigation of my project, I'd like to locate some masterfully-recorded tympani and pipe organ source to supplement my electronic test equipment and synthesizer. Ideas anyone? May the source be with you Luke!
As I previously mentioned, I will be constructing the "low compromise" bass horn, additionally, I will be employing a custom built driver with this horn -- I'm currently looking at a driver with 10Hz Fr. Everything analog in my signal chain will be targeted to reproduce audio to 5Hz, RME's cards appear to be able to support 5HZ, however my inexperience with Alsa/Linux-sound has led me here.
Thanks for everyone's continued dialog in this area.
Regards,
Ronan
On 2/2/07, Gene Heskett
<gene.heskett@xxxxxxxxxxx> wrote:
On Friday 02 February 2007 04:24, Dominique Michel wrote:
>Le Thu, 1 Feb 2007 16:15:20 -0800,
>
>"ronan mcallister" <bass.woofer@xxxxxxxxx> a écrit :
>> Bill, Sergei,
>>
>> Generally, I am investigating the limits/extent of what I can do with
>> Linux/Alsa/DSP as an alternative to commercial equipment in these
>> three areas:
>>
>> 1. the live concert scenario (we currently do everything analog now)
>> -- as previously discussed.
>> 2. home theater / hi-fi
>> 3. something I haven't mentioned before: using WinAudioMLS and RME
>> 9632 as a RTA (I know this will work) -- eg measurement/RTA for both
>> home hi-fi and prosound / live concerts.
>>
>> All of these to extend below 20Hz as far as I practically can.
>
>Which instrument can play a note below 20 Hz? Even the biggest church
> organs cannot do that.
I'd have to assume you have not been there, and heard them then. All
you've heard are recordings of them.
The individual pipe may not, but the harmony or beat between two 32 foot
pipes can easily reach considerable energy levels well below 20 hz. Even
the 16 footers can 'shake your guts' at the right close harmony notes.
Our own organs 16 and 32 foot pipes rank each other across the backdrop
behind the the pulpit stage, the larger ones almost 7" in diameter and
reaching the ceiling 3 stories up, and they have no volume control like
the other 7 or 8 ranks of pipes which have huge adjustable louvers
between them and the public. When the stops are pulled to bring those
puppies on, several hundred tons of stone masonry building feels like it
gets up and marches down the street.
>> Sergei, I will be digitizing my SACD audio output via a RME card etc
>> as I think you must be right about interfacing a SACD to Linux
>> directly/digitally... And I want an analog input/output capability if
>> at all possible as after all the real world is analog!
>
>You must look at the alsa soundcard matrix:
>http://www.alsa-project.org/alsa-doc/
>
>After, you must be aware of one thing: at alsa support analog
> input/output capability don't mean at the hardware is capable to output
> frequencies below 15 Hz.
>
>> I'd like to think if I had LF response down to 5Hz, besides the
>> vibration through direct bone conduction, I might realize improved
>> transient and phase response in the audible range, resulting from the
>> extended LF response of my audio system. What do you think?
You'll usually pickup, and by non-linearity and harmonic effects make
audible, a lot of air conditioner and other air movement noises. Its all
a big compromise.
>Technically speaking, this is the only point where a so low bass
> response will do something good. But it is no speaker on the market
> that can do that.
They can be built, and in much smaller cabinets than the famous Altec
Voice of the Theater sizes which were actually built huge for efficiency.
We once rebuilt the relatively small box the Bozak floor model came in,
about 28" tall by 24" wide, 15" or so deep, an infinite baffle design.
Replacing the 10" B305 driver with a B305AL which had a 2" throw,
stiffening up the box with cross bracing till it clicked like marble when
tapped with a mallet anyplace on it, and added about 3x the normal sound
absorber material inside it. Cook used to make some 78 rpm lp's intended
as demo records for us 'hi-fi' peddlers to use, and one of them had
several tracks of percussion solo's. The tympani track was a favorite to
demo that speaker with as it went on for about 45 seconds, then you could
hear the squeak of the peddle linkage as he let the drum skin go slack
after the last strike at the end. A normal OOTB speaker did the squeak
and that was the end. With the rebuilt box, the room went up and down
several times after the squeak. This was 47 years ago, using a 30 watt
McIntosh amplifier, or a Dynaco of about 20 watts.
>For what I know, the first subsonic experiences was made by the nazis
>during WWII. They was torturing prisoners with subsonic frequencies. So
> be careful with it. In fact, even frequencies between 25 and 50 Hz can
> have a physiological impact on the body, It is a very complicated
> matter because we all know at we don't feel the same after listening to
> a concert of hard rock or salsa music.
>
>This paper can be interesting to you: Acoustic Weapons—A Prospective
>Assessment: Sources, Propagation, and Effects of Strong Sound
< http://www.einaudi.cornell.edu/PeaceProgram/publications/occasional_papers/occasional-paper22.pdf>
I made the link clicky, its an excellent treatise on the subject.
--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2007 by Maurice Eugene Heskett, all rights reserved.
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