Topic: Core Sound TETRA Questions for LEN

[Nick's Picks]

your retail post is locked, so i can't ask there.

1.  4 channel output via a custom cable, probably 5 or 7pin > 4x male XLR ?
2.  is there an "outboard" controller box to select polar patterns, provide phantom ?
3.  will it operate in any mode other than "A format" ?
4.  does it come w/bundled software so that you can actually do something w/the files ?

Basically...
lets say I'm joe taper.  I want to buy this mic and use it in the field.
what do I need to go from "in the field" to "in the living room" mixed down two channel stereo ?

would I need something like an R4 w/4 channels of preamp / phantom ?

this product looks really cool, and i'd love to get my hands on one.  but there are a lot of holes in the marketing, almost like you expect the end user to know what they need to do w/this microphone.
Its very intriguing, but mysterious.  Can you provide a list of materials one would need to use one of these for concert taping ?

[Nick's Picks]

I answered a few of my own questions by reading the site.

it comes w/the appropriate software ?  not sure on that.  it comes w/something, but I dont know if its the entire package or just a plugin for something else.

it works w/the Core-Sound "4mic" preamp/AD...which isn't shipping ?
will it work w/any 4 channel recorder ?

[WiFiJeff]

I have to admit to being totally pissed off a month ago when I attempted to learn something useful about this system.  Even though I have dropped a lot of cash over the years with Core Sound (several sets of mics, including two high-end binaurals, one configured for the Mic2496 and PDA system I could never get to work reliably, a Jecklin disk, cables, etc.) I was treated by Len more like an industial spy than a prospective customer.  Since no response curves for the mics are given, and the claimed response range is limited to below 18.5 kH, I was concerned whether the drop-off was smooth or abrupt.  The type of mic used is being treated as a deep secret, though I am told that, by inspection, lots of guys have IDed it as a common Chinese cap.  Len's reaction to my question on hf response was "How old are you?" I guess implying I couldn't hear that high any-old-how (this from a guy selling 24/96 gear, yet).  So when I make the move to surround, it's going to be Soundfield or Josephson C700S, even if they cost five times as much.  At least I'll have some confidence I'm getting something useful.

Jeff

[boojum]

"Everyone knocks stones from a crumbling wall."  I had trouble with Len, too.  I asked him about a set of expensive mics and he never took the time to respond.  So I bought them from Sweetwave, who treated me very nicely.  I cannot be bothered with retailers on the Internet who cannot answer their e-mails.  Too many good companies do.   YMMV   

[illconditioned]

I have to admit to being totally pissed off a month ago when I attempted to learn something useful about this system.  Even though I have dropped a lot of cash over the years with Core Sound (several sets of mics, including two high-end binaurals, one configured for the Mic2496 and PDA system I could never get to work reliably, a Jecklin disk, cables, etc.) I was treated by Len more like an industial spy than a prospective customer.  Since no response curves for the mics are given, and the claimed response range is limited to below 18.5 kH, I was concerned whether the drop-off was smooth or abrupt.  The type of mic used is being treated as a deep secret, though I am told that, by inspection, lots of guys have IDed it as a common Chinese cap.  Len's reaction to my question on hf response was "How old are you?" I guess implying I couldn't hear that high any-old-how (this from a guy selling 24/96 gear, yet).  So when I make the move to surround, it's going to be Soundfield or Josephson C700S, even if they cost five times as much.  At least I'll have some confidence I'm getting something useful.

Jeff

I'm guessing the capsules are similar to what Chris Church is using.  I do in fact know a source of these, but I'm not disclosing out of respect for Chris.  My opinion: this is a great budget-priced, utility-grade capsule, but I would not trust them for high end imaging market the tetramic is aiming for.  Until someone (Core sound, or otherwise) discloses the capsule type and/or detailed specs (and all the other stuff people are asking about actually using the mic!) I wouldn't spend any money on this stuff.  I mean we are spending big money, we should at least get some technical information.

IMO "Joe taper" is probably going to be much happier with, either a pair of Neumanns or Beyers, or, I guess an MS setup, however that is achieved.

I've considered building an ambisonic mic, but if I did, I would probably build from the Sennheiser MKE40 capsules.  It might would be more expensive to build, and it would probably need some EQ to improve the LF response, but I do like that capsule for the level of detail.

A final question concerns patent issues.  Is the Soundfield patent still active?  Is tetramic violating patent?

  Richard

[Mr.Fantasy]

A final question concerns patent issues.  Is the Soundfield patent still active?  Is tetramic violating patent?

Tune in next time...same bat time, same bat station....

[DSatz]

WiFiJeff, I don't wish to defend anyone's bad attitude, but by itself a rolloff in a microphone starting at 18.5 kHz is little cause for concern. Some of the ribbon mikes that some people think are so f'ing great roll off starting at 7 kHz, and you might be amazed to see the actual high-frequency response of some very highly regarded studio condenser microphones (particularly off-axis) as opposed to their published spec-sheet curves.

But as I said this is little cause for concern since at such high frequencies, there is rarely any significant sound energy even in "acoustic" music at normal recording distances--and if you record amplified music, forget it--there's essentially none at all.

You remarked on the fact that this person sells 24/96 kHz equipment. For the past five years or more it has become impossible to market any digital recording system that doesn't support at least 96 kHz. But the point of it was never to capture higher frequencies than 44.1 kHz can record; it was to capture the audible range more accurately. Any PCM audio system requires low-pass filters to exclude any frequencies at or above one-half the sampling rate. A sampling rate of 44.1 kHz, while objectively adequate for all frequencies audible to humans, leaves only the very small interval between 20 kHz and 22.05 kHz for this filtering to take effect.

The main justification for 96 kHz recording, such as it is, is to allow those filters to begin their effect higher in frequency (above 20 kHz) and to have gentler slopes. This allows for flat frequency response to 20 kHz plus better impulse response in the audible range, both of which can be measured and occasionally even heard by some people on some material when listening on electrostatic headphones--though not by most people on most material, and certainly not on any normal home loudspeaker systems.

Please pardon me if you already knew all this; I'm just trying to contribute a little perspective. I might have been interested in that system as well, except that having great versatility in processing the signals from crappy capsules ultimately isn't going to produce any results to get excited about. It was always the problem with the original Soundfield system (I'm thinking 20+ years ago) that its Calrec capsules just weren't really very good sounding, though I understand that the more recent ones are quite a bit better. Still, I have no use whatsoever for height information in a recording, and would rather use a mike with three really good capsules and correspondingly simpler processing.

--best regards

[udo]

I believe a double ms setup with three really good microphones and a 4-track recorder (modded R4) will bring much, much better result. But then again a 2 Schoeps CCM4 and a CCM8 + the Rycote suspension cost you BIG money, but you will at least have sound that is as good as the schoeps stereo recordings. And for music recordings: we need to record only two dimensional, there is not too much sound coming from the sky (or the ceiling ...) usually.
On this site you will see someone experimenting with a self-made surround sound version ...
http://www.uwm.edu/~type/audio-reports/QuadPacConstruction/index.html
I believe there are many ways to experiment with different (and cheaper) microphones then schoeps. The tetra mic reminds me a bit of the first compact-stereo systems, which were marketed as the great thing, everything included, but the sound is poor.

[live2496]

Perhaps we will hear from Len soon, but I can fill you in on what I know about it.

You need to record to discrete tracks and then run the audio through a post conversion process to convert into B-format. Once in b-format, there is software that can decode the ambisonic b-format file into multiple speaker feeds depending upon your speaker configuration.

Each microphone needs calibration to account for differences in capsules.

This is probably the most advanced software to date here...
http://www.kokkinizita.net/linuxaudio/tetra-pict.html

It's a linux software for calibration of the tetramic and conversion of a-format to b-format.

This is a new area for software development. Another person is developing plugins for OSX.
The best source for information I think is the wiki on www.ambisonia.com.

A number of decoders are available. One for windows is called VVMIC, but there are others. There is a java based player also. Some of this information I posted in Teddy's thread about Audio Reference.

edit: apparently the VVMIC developer has plugins also available for windows. These are VST plugins that should work in an windows recording app that supports VST. This makes it possible to encode to b-format while recording.

[Nick's Picks]

ok, so you record 4 raw channels of A format.
then you need to convert that to B format, which has been around for a while and there are software packages out there (just like for the soundfields), and from there you can do all your picking/chooseing w/the angles and polar patterns.

those capsules looked at first like Audix.
whatever they are, I wonder if they sound any better than Oktava mk-012 version of this array.

one thing I dont like is the look of this mic.  Its small, thats cool.  But it looks like something I used to clean my bong with.

I saw one pictured in a stereophile magazine recently (as they were doing some recording and documenting it).  they were not using it, it seems Len was there and they just snapped a pic of it.

Still...
Len, if you want a review on nickspicks.com.  get a kit together for me consisting of the mic and the 4mic box (if that's what you recommend) and let me see if this sucker is going to rock the taper world...., or just be a stack of paper (precision) weights.  I'd love to give it a fair go.
 

[Church-Audio]

I have to admit to being totally pissed off a month ago when I attempted to learn something useful about this system.  Even though I have dropped a lot of cash over the years with Core Sound (several sets of mics, including two high-end binaurals, one configured for the Mic2496 and PDA system I could never get to work reliably, a Jecklin disk, cables, etc.) I was treated by Len more like an industial spy than a prospective customer.  Since no response curves for the mics are given, and the claimed response range is limited to below 18.5 kH, I was concerned whether the drop-off was smooth or abrupt.  The type of mic used is being treated as a deep secret, though I am told that, by inspection, lots of guys have IDed it as a common Chinese cap.  Len's reaction to my question on hf response was "How old are you?" I guess implying I couldn't hear that high any-old-how (this from a guy selling 24/96 gear, yet).  So when I make the move to surround, it's going to be Soundfield or Josephson C700S, even if they cost five times as much.  At least I'll have some confidence I'm getting something useful.

Jeff

I'm guessing the capsules are similar to what Chris Church is using.  I do in fact know a source of these, but I'm not disclosing out of respect for Chris.  My opinion: this is a great budget-priced, utility-grade capsule, but I would not trust them for high end imaging market the tetramic is aiming for.  Until someone (Core sound, or otherwise) discloses the capsule type and/or detailed specs (and all the other stuff people are asking about actually using the mic!) I wouldn't spend any money on this stuff.  I mean we are spending big money, we should at least get some technical information.

IMO "Joe taper" is probably going to be much happier with, either a pair of Neumanns or Beyers, or, I guess an MS setup, however that is achieved.

I've considered building an ambisonic mic, but if I did, I would probably build from the Sennheiser MKE40 capsules.  It might would be more expensive to build, and it would probably need some EQ to improve the LF response, but I do like that capsule for the level of detail.

A final question concerns patent issues.  Is the Soundfield patent still active?  Is tetramic violating patent?

  Richard

I am using the same capsule. But I modify mine in a few different ways to bring out the performance. I dont know what Len does to his capsule but as them come stock they are not much to cheer about.  And I carefully hand match all of my capsules to 0.04 db max of each other. As ones from the same batch can be off by as much as 6 db from each other I buy large amounts and find good matches. They are a good sounding capsule once you do a few things too them. 

[WiFiJeff]

WiFiJeff, I don't wish to defend anyone's bad attitude, but by itself a rolloff in a microphone starting at 18.5 kHz is little cause for concern.

I understand.  But would you spend $1000 on a mic with no polar or frequency charts (however misleading those may at times be), using a mysteriously-sourced capsule, and no other info?  It's not like I was offered a better package of specs or comparisons.  

You remarked on the fact that this person sells 24/96 kHz equipment. For the past five years or more it has become impossible to market any digital recording system that doesn't support at least 96 kHz.

He was an early adopter of this marketing ploy.  I bought the PDA-Audio stuff as soon as it was out, only to have the first six months go by as a nightmare beta test since almost nobody was able to get a system to run at 24/96, some of the original gear and software that was supposed to make it run just couldn't.  By the time the software and PDAs that would work were becoming useable there were better smaller more reliable options available.

This allows for flat frequency response to 20 kHz plus better impulse response in the audible range, both of which can be measured and occasionally even heard by some people on some material when listening on electrostatic headphones--though not by most people on most material, and certainly not on any normal home loudspeaker systems.

I use the Stax electrostatics, a superb system.  Makes it hard to listen to any loudspeaker playback.

Please pardon me if you already knew all this; I'm just trying to contribute a little perspective. I might have been interested in that system as well, except that having great versatility in processing the signals from crappy capsules ultimately isn't going to produce any results to get excited about. It was always the problem with the original Soundfield system (I'm thinking 20+ years ago) that its Calrec capsules just weren't really very good sounding, though I understand that the more recent ones are quite a bit better. Still, I have no use whatsoever for height information in a recording, and would rather use a mike with three really good capsules and correspondingly simpler processing.

Your input as usual is very helpful.  I am leaning to the Josephson C700S just for these reasons.  

Jeff

[muj]

[/quote]

Your input as usual is very helpful.  I am leaning to the Josephson C700S just for these reasons.  

Jeff


[/quote]




If you buy that mic I'll kiss your feet

[DSatz]

WiFiJeff, I haven't dealt with Core Sound enough to have an opinion about the service or the attitude, but I do know David Josephson--he's one of my personal heroes in the audio profession. I sometimes wish I had a good excuse to buy something from him. You can count on his honesty and sincerity, as well as a good deal more knowledge and common sense than a lot of other people who promote their supposed expertise in this field.

--best regards

P.S.: I haven't heard Stax Electrostatics in almost 35 years now, but used to have a pair of SR-X phones and one other model of theirs, plus a little tube amplifier to drive them. They sounded too good, was the problem--if I made a so-so recording, it would still sound good through those headphones.

As a musician I learned to practice in a room that made me sound bad until I could sound good in that room--then I'd be ready to sound good almost anywhere. Same thing with live recording--if a playback system coats everything with sugar, let me save that for when I do playbacks for certain clients, but for my own criticial listening I want the most neutral sound possible. Headphonewise, for me that would be something more like Koss electrostatics, though again headphone listening is fundamentally deceptive and inadequate; if I'm recording primarily for loudspeaker playback (i.e. all the time, practically speaking), I need to monitor over loudspeakers to know what I'm doing.

[Nick's Picks]

if only those c42s of his were not so bright...i'd be all over a pair.