https://www.youtube.com/watch?v=X23hZNoSkUs
The Calrec Soundfield mike, the practical implementation of Michael Gerzon &
Peter Craven's invention, was how I got involved in microphone design.
It was incredible just being with Michael .. a guy with a brain truly the size
of a planet.
The Mk4 wa
.. a reply to stuff on the "Anyone had experience with AllRAD decoding to
physical loudspeakers?" thread where Aaron brought up the topic of NFC.
" A practical problem is that forward NFC filters have infinite gain at DC.
Jerome Daniel's solution is to have a reference decoding distance for
Ambis
> Behringer ms10s that withstood months of tropical storms in the Amazon -
so
Have you got that model number right? I still think the cheapo solution is
the way to go .. but it would be good to know what has worked for you ..
even if it isn't 35 yrs. I get MS20 and loads of other stuff but no
> If you needed speakers for a permanent outdoor installation with speakers
than need to last decades - does such a thing exist ?
> However here the real issue is who will provide a maintenance
package/guarantee for 35 years ?
If you want to keep the same speakers for 35 yrs, your maintenance co
There's a number of issues brought up in this thread which Core Sound have
been aware of for some time and have been attempting to address. But its
difficult for a small company to make major changes on the small turnover.
For what its worth, the 'new' PPAc will give around 1dB improvement in
If anyone has recordings of any of this Matrix H, HJ, UHJ stuff, please
post a copy on
http://ambisonia.com/
with a good description of what it is and the circumstances.
I don't think UHJ is dead yet as the biggest present market for music is 2
channel stuff for headphones and UHJ gives excell
> Most days I would agree with you: but there is always Murphy's Law to
contend with, and the specific case of this states that a PP3-powered
recording device will fail only when a unique event is to be recorded.
Ha! In my limited experience, Murphy is MUCH more likely to strike at
rechargeabl
> The Tetramic spec declares 3.5mA x 4 capsules (=15mA) @48V - that's
720mW
> But to power through the PPac it's 9-12V @<10mA - that's 90- 120mW - a
big difference.
The P48V current consumption is pessimistic. Powering directly bypasses
the regulation required for P48V.
You also avoid noisy
Can you give us more detail about these tests and perhaps put some of these
natural recordings on ambisonia.com?
The type of soundfield microphone used .. and particularly the accuracy of
its calibration ... makes a HUGE difference to the 'naturalness' of a
soundfield recording.
Some good exam
> The main mechanisms for disambiguating 'cones of confusion' (and this
includes front-back reversals) are: pinnae effects (Batteau) and
head-movements (Wallach) - so, without either of these mechanisms at play,
one would expect directional ambiguity.
You can test the relative importance of the
Aaron Heller wrote
> Marc Lavall, Eric Benjamin, and I put together a Trifield (three speaker
> stereo) plugin and demo'ed it a Burning Amp last fall. It is hosted at
https://bitbucket.org/ajheller/trifield/overview
> There are also some plots that use Gerzon velocity and energy localization
> I have a question for the keepers of ancient wisdom: how does one remove
the capsule assembly from a Soundfield MK IV microphone? I have one on
which the 1 kilohm "capsule heater" resistor has gone open circuit. The
cone on the MK V and newer is split and comes apart pretty readily, but the
M
Just to bring everyone down to earth ..
There are two easily reproduced experiments first carried out by prominent
members of this group which put these effects into perspective. They are
the
Greene/Lee Neckbrace
and
Malham/Van Gogh Experiment
The first shows 'real life' Fixed Head Localisati
This is likely an implementation of Ambiodipole / Stereo Dipole / Transaural
http://ambisonia.com/Members/ricardo/StereDpl.htm/
There's pretty pictures on the ISVR website that show 'some' measure of
wavefield (soundfield?) synthesis takes place .. certainly more than with the
usual +/-30 stereo.
oundField Mk IV
What's the difference between #641 and #650??
Dave
On 19 October 2015 at 06:38, Richard Lee wrote:
> > Interesting: https://www.gearslutz.com/board/11410162-post650.html
>
> I endorse Rudy's mods described in #641 and #650
>
> Ken Farrar did some
> Interesting: https://www.gearslutz.com/board/11410162-post650.html
I endorse Rudy's mods described in #641 and #650
Ken Farrar did something similar to his #641 mods in the Mk5
... but I think his post should be titled "Where Beach Bums & Angels fear to
Tread" :)
_
> A known floor noise of the dr-680 in high gain is from the phantom power,
and the?Busman mod changes some components on the preamps, like some
condensers and the opamps, and those condensers could be the solution on
that kind of noise, but not all.
The biggest noise on dr-680 mk1 is poor phan
How is the Oktava Tetrahedral mike calibrated?
In what form are the calibration files?
Can you post a copy of the User Manual for it?
http://www.oktavausa.com/ProductsPages/Ambient4DMic.html has no info at all.
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Mathias, can you please post these recordings on ambisonia.com
The Furse-Malham *.AMB format allows up to 3rd order
These would be the first publically available live HOA recordings of music from
a HOA mike and may re-surrect the discussion of HOA decoders
Which Soundfield did you use?
What wa
Fons, have you heard any music recordings with EigenMike? No one seems to
have tried.
Elko has a standing invitation to bring EM to any venue that Aaron & Eric
are recording world class orchestras in good halls ... I mean obscure Mid
West bands in non-descript halls :) They can reliably recor
Duu.uuh!! http://parole.loria.fr/DEMAND/DEMAND.pdf states
"the microphones of the array ... are not calibrated with respect to each
other, and so gain variations are to be expected: we found that the energy
in some channels is consistently higher than in other channels. Algorithms
working on t
The strict answer to your question is in Gerzon's
"The Design of Precisely Coincident Microphone Arrays for Stereo and
Surround Sound"
http://www.aes.org/e-lib/browse.cfm?elib=2466
There's a corrected copy at
https://groups.yahoo.com/neo/groups/SoundfieldMic/files/Ricardo/. You
might have to
The question isn't whether 'music' has frequencies below 1/zillion Hz.
It's whether such content adds to the MUSIC.
This is the case ONLY with organs reproduced properly.
You can check this with DBLTs. The speaker that has come out top in every
single DBLT it has been in nearly 2 decades (som
There is an important reason to maintain full Ambisonic capability to below
20Hz.
It is a MUSICAL one.
Go to a service at a large cathedral with good organ. At the end of the
service, the organist will play something to show off while everyone is
leaving. You can walk around and listen at va
I'm so sorry to hear that.
In my younger days, I always thought of him as the handsome dashing young
Prince of Ambisonia, a foil for Grand Vizier Malham.
Ken Farrar was Chief of the Dwarves with Clem Beaumont his resident
Sorceror.
Michael was a Yoda type character with Geoffrey Barton sorta l
> It's certainly true that some decoding methods can become highly unstable
when provided with an inadequate number of speakers and/or an uneven
distribution.
> However, the Rapture3D decoders (including the TOA ones) do NOT have this
problem. One of the core features of the Rapture3D decoder g
Just a short note about noise.
While the ST450 is slightly quieter than TetraMic, in practice, TetraMic
noise has never been a problem when Recording Music .. even in very quiet
studios.
Paul Hodges recorded his son in the Warehouse, a well known studio in
London, so you can judge for yourself
> that's the main problem with the eigenmike: the higher the order, the
> narrower the bandwidth and the higher the lower boundary. which means that an
> eigenmike signal set will not usually be downwards-compatible - if you aim
> for a correct amplitude response for the full 4th order set, it w
I must agree with Fons on Eigenmike.
IMHO, Angelo's software for Eigenmike is loads better than what's supplied by
the makers. Its nea...aarly good enough for recording music but certainly
not there yet. There's a paper on the new software on Angelo's website.
I'm not sure if there is a
> I;ve a suspicion that a Soundfield mic wouldn't behave well in such a weirdly
> reactive environment - i seem to remember chatting with Angelo Farina about
> this some years ago - anyone shed light on that?
There's quite a lot of work being done on using TetraMic for Sound Intensity
stuff. I
> I;ve a suspicion that a Soundfield mic wouldn't behave well in such a weirdly
> reactive environment - i seem to remember chatting with Angelo Farina about
> this some years ago - anyone shed light on that?
There's quite a lot of work being done on using TetraMic for Sound Intensity
stuff. I
> Unless things have changed a lot, last I checked lossy compression messes up
> phase relationships, and that would be an issue for things like UHJ, which as
> long as portable stereo players with limited battery life (and thus limited
> CPUs), is the only viable, because stereo compatible, dis
As I've said ad nauseum, the guy who first integrates an Ambi decoder into VLC,
getting around the evil Windoz mixer etc. gets to choose the data structure for
next important Ambi format.
This will be a lossy compressed format probably based on the public domain
Vorbis.
Ambisonia was the 1st m
> I mean that instead of a cone there is a sphere, and able to emit sound in
> all directions I'm guessing if it hasn't been done its because it presents
> considerable technical difficulties - still ...
There are no serious difficulties as long as size & $$ are not constraints.
But apart from
.. was Somting for the Weekend - Commerisal 3D sound
> Sure, the center phantom image generated as a sum of two identical L/R
> signals sounds a little different. But little is the operative word. ... Most
> people do not notice this at all.
It's not that we don't notice but that we are so used
> well, depends. iirc, theile's argument is that a two-speaker phantom source
> should be a mess in terms of spectrum, but isn't (as two-speaker stereophony
> demonstrates). so for some reason, the brain is able to sort it out. more
> than two correlated sources, and things go awry, e.g. L/C/R
>> except its not quite the same effect. If I hear a plan(ish) wave in nature
such as in thunder or a very distant giant waterfall
Distant thunder is often an extreme case of Proximity effect. Velocity
components are boosted at LF compared omni components.
You encounter this if you are using Tetr
No. Ambi Super Stereo isn't just feeding the stereo into a UHJ decoder.
This is a post from 2006. I'd recommend a "Width" control so you can decide
how wide you want your stereo.
All the decodes here are basically the same with different "Width" settings.
Only minor differences, with prefere
You can't make naive predictions on what ambi stereo decode will sound like
that; especially when you have j terms. You have to apply the full General
Metatheory ...
http://www.aes.org/e-lib/browse.cfm?elib=6827 It should be in Sampo's
motherlode too.
- Decode the W' X' Y' signals to a spea
> can a tetrahedral mic be used to create a room (correction) impulse response
> in B format? and how?
Yes.
I can make a sensible attempt today for an Ambi rig spaced away from the walls
as the HiFi pundits and other gurus have mandated for years. This however has
near zero Wife Acceptance Fa
> I've recorded with Tetramics and I've set up an HSD 3D system
Mark, what is this HSD 3D system?
Can it play Aaron's B-format recordings?
If you have been following the BLaH series, what we've found is that hardly any
software decoders do plain FOA properly.
___
I tend to agree wi
> Richard, you gave me quite a chuckle there Microsoft software invention
> indeed!
You think I'm joking? IIRC it was GV Malham, in 2006, who pointed out that
Redmond did indeed have such a patent application.
Giuseppe, you should know that inscrutable Orientals have no sense of humour !
> cardioid = 1/2 ( sqrt2 W + X )
> but for Mid-Side decoding from B-Format, where M is the same cardioid
> component, I often find this equation:
> M = sqrt2 W + X
This is an instance of a patented Microsoft software invention called a Volume
Control. There are also ancient hardware implement
>> I find it much easier to identify UHJ with natural recordings
> By this, do you mean recordings that you _know_ in beforehand?
> If I gave you 5-7 recordings, would you be able to pick up the UHJ encoded
> recordings from them? Some of my examples would include audibly and
> measureably simi
> This is especially difficult with acoustic recordings, ..
I find it much easier to identify UHJ with natural recordings made with a
single properly aligned tetrahedral mike; especially if there is a nice
acoustic. Many of the early recordings by Music for York and the original
Ambisonic team
Svein Berge shows the ST350 capsule assembly at
http://harpex.net/
My thanks to him. I want to know if this "new" stronger assembly, with the
capsules secured by screw on rings, is used in the ST450 or if they have gone
back to the "old" assembly using screws as in the Mk4, Mk5, ST250, SP422.
Would any of you who have used or have a ST450 Soundfield know if it uses the
"new" stronger capsule assembly introduced in the ST350
or
if they have gone back to the Mk4, Mk5, SP422, ST250 assembly
You can check without dismantling the mike by shining a strong light through
grille.
The "old"
> More and more it seems that the modern incarnation of BBC is interested
in ambisonic, and whatnot.
>From my beach in Oz, I have a sense that this new BBC Ambi interest is from TV
>rather than Radio.
In my Jurassic days, there was a strong atmosphere of "never the twain shall
meet". I would
http://www.impublications.com/content/a-pair-of-wharfedales
I never met the Old Man but still cherish a letter in reply to a query of mine
on how to enter the British loudspeaker industry.
Like all who had even the slightest contact with him, his warmth, generosity
and encouragement were never
> The actual shelf gains (the difference between LF and HF gain for any
> component) don't tell the real story. Changing the LF or HF gain for all
> components by the same amount doesn't modify the decoding, it just results in
> some EQ.
Du...uh! I stand corrected. Shelf filters change the ra
http://ambisonic.info/info/ricardo/shelfs.html
This is now only of historical interest. My latest thinking on Shelf Filters
is encapsulated in BLaH3 "Is my decoder Ambisonic?" where Aaron's clarity puts
me to shame and explains why I'm still a beach bum.
The only useful info there which isn't
Daniel, Lynne wasn't the only girl assembling & covering the capsules but
she was the best.
> The capsules, though, do seem to have had a makeover, at least as far as
I can see through the grill with the aid of my trusty LED keyring torch.
The front edges of these are now bevelled, unlike those
1989 was when Steve Jagger, Ken Farrar and some of the other original
Calrec mob bought the company back from AMS. They left the Soundfield with
AMS.
AMS had problems making the mike consistently.
When Soundfield Research took over, they dug Lynne out of retirement. She
used to make the Soun
> Peter also mentions the Meridian software decoder, which is not
available. However there are plenty of software decoders available for
download.
Duu.uuh! Mr. Elen, could you please provide some links to these. I've
already checked the Unobtainium Software website for software UHJ decoders.
> Now, if it is BMX then it should be decodable in the same way I decode QS
(and SQ) as QS was based on RM
If it was from Calrec in 1974, it is more likely to be based on RM which
was based on QS (rather than the other way).
If the recording was made in a nice hall, you can hear the difference
> How does the eq make the capsules more(virtually)coincident?
http://tech.groups.yahoo.com/group/SoundfieldMic/files/Ricardo/
has details. The phase as well as the amplitude has to be corrected.
> What would the noticable audible negative side effects of an ambisonic
mic be which was not adju
The change to UHJ at that time is very small and was made just to get rid
of the need for another phase shifter in the decoder (IIRC).
Any of the Classic Decoders, the Integrex, Minims, A&D etc will decode this
properly.
I for one would be most interested in a copy of the recording as it
repre
There's loadsa good stuff being discussed here. If I can comment on just
one or two
> When listening to this through a speaker rig, we hear this boost and tend
to interpret it as meaning the sound is close especially in a dry acoustic
with a Greene-Lee head brace etc., etc.,. However, sur
> It is true that 1st order ambisonics doesn't consider distance, with all
sources being reproduced at the distance of the speakers,
.
> synthesis, the ambisonic encoding equations do not include distance,
Both of these are untrue.
For the second, see the Appendix of BLaH3 "Is my decoder Amb
Anyone got a copy of
HD Harwood: "Stereophonic Image Sharpness"
(Wireless World, vol 74, 1968, pp.207-211) ?
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Steve Thornton is selling a coffee table book based on his encyclopediac
photographic record of OUTRS and other stuff.
Be the first to brag a limited edition hardcover link which goes back to A.
Blumlein Loadsa stuff on the rise & fall of quad, surround and the
early history of Ambisonics
> This sqrt(2) factor is an endless source of confusion. It seems silly that W
> should be divided by sqrt(2) in recoding to restore its value, which was
> multiplied by this in the encode to UHJ.
This sqrt(2) factor is WRONG. Where do people come up with such myths?
The Encoding eqns on http:
IIRC, Mark Decker recorded a BBC radio drama where a man is killed by being
tied up in a bellfry with the bells pealing away.
Can't remember the title but I remember reading a web page where he describes
this experience which was his first use of a Mk4 Calrec Soundfield.
I'd appreciate a link t
I have questions about UHJ decoding too.
Richard, how did you get your decoding eqns?
My question is about
http://en.wikipedia.org/wiki/Ambisonic_UHJ_format
It has separate decoding eqns for 2 & 3 channel UHJ. They are consistent
except for Y
Y = 0.763*D + j*0.385*S 2-channe
I hope you have a control where you measure "real" distance perception too.
Not having a "real" control is a fault in many localisation experiments.
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You must simulate at least 2 things.
At close range, you must simulate the curvature of the soundfield. This is
simply proximity for 1st order and the effect is, if anything, exaggerated.
see the Appendix of
"Is My Decoder Ambisonic", Heller et al, AES San Francisco 1980 aka BLaH3
See Daniel
RFI protection is a complex & little understood subject. "Pro" mikes differ
hugely in their susceptibility. There are famous mikes from famous names which
are terrible. The preamp input also needs to be RFI proofed.
Though I lust after a SD 788, Jim Brown says its input socket shells may not b
When I was the R&D teaboy at Wharfedale in the late 70's, I tried stereo in our
anechoic chamber; expecting great things w/o pesky room reflections. The
results were terrible; poor stereo sound as well as formal localisation which
was the reason for the experiment. Both much poorer than in a nor
> [1] Loudspeakers and the Stereo Seat - G Millward, HFN, 1981?
> It's
> Millward, G; Loudspeakers and the Stereo Image, Hi-Fi News 29, nov84,
> according to
http://decoy.iki.fi/dsound/ambisonic/motherlode/source/AmbiLoc2.pdf
> by a certain R.L and A.H. ;-)
Thanks to Grand Vizier, Don Malh
I think this is a virgin field of research.
On the practical design of "line sources" for large venues, it may be that we
can only achieve "..more even coverage, as you increase the distance from a
speaker system to the nearest listener. This also makes it rather more
comfortable for the neares
When I was R&D tea-boy at Wharfedale, I spent time trailing around the country
with Barry Fox our Promotions Manager, putting on lectures/demos & shows.
Part of the stuff we carted around was the Wharfedale Ambi rig which was
- 12 x TSR110 speakers
http://www.gramophone.net/Issue/Page/October%2
I hope all of you will join BLaH in thanking Etienne for the immense efforts
and huge amount of time money that resulted in Ambisonia. It must have seemed
thankless at times.
I am certain it has been a major factor in the resurgence of interest and much
new work on Ambisonics and surround soun
I had a page on ambisonia.com with a lot of what has been discussed and was
trying to find it before Jerry, who provided much of the info, noticed our
discourse.
Unfortunately ambisonia.com seems to be unobtainium. I know this has been
asked before but is ambisonia.com archived anywhere and wi
> As far as I was aware, the only example of this SFM version (a very early
one) was at Peter Fellgett's house and I was hoping this and other Ambisonics
memorabilia would eventually find a place in a museum somewhere. I have
contacted his family to ask if they still have this array. I certainly
http://cgi.ebay.com/4-Calrec-matched-vintage-CB1000-microphones-Ambisonic-/2
60699856275?pt=UK_Music_Instruments_Microphones_MJ&hash=item3cb2ec1d93
is a piece of history up for sale.
It also has a link to
http://www.michaelgerzonphotos.org.uk/index.html
which is a fascinating portrait of a in
Ay haf seen the light!
Repent yus sinners, unscrupulous profiteers, snake oil salesmen, deceivers and
evildoers!
Fall on your knees and beg forgiveness for what you have done to the US of A in
the false name of progress !
http://www.youtube.com/watch?v=VCzi75bhOcI&feature=player_embedded#!
>F
>As to the polarity issue, L,R are indeed inverted w.r.t. X,Y,Z
>for front, left, up respectively. It could be the Lemo to XLR
>breakout cable - did you check the wiring ?
The Mk4 had WXYZ inverted wrt stereo outputs. I think the stereo outputs are
"correct". (pressure increase -> Omni increase)
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