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Author Topic: miniDSP AmbiMIK-1 Ambisonic Mic  (Read 2763 times)

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Offline DSatz

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Re: miniDSP AmbiMIK-1 Ambisonic Mic
« Reply #30 on: August 29, 2020, 08:44:19 AM »
My posting above was based mainly on what I learned at an AES presentation about USB for professional audio, back when USB was around the 1.1 version level. It wasn't highly regarded for professional audio at that point, but not mainly because of bandwidth per se. Even then the bandwidth was sufficient for some applications. But that sufficiency was based on uninterrupted good conditions--mainly, on not using the same computer for anything else or putting any other peripherals on the same USB bus (sorry, that's redundant the way "ATM machine" is redundant).

The USB protocol for host devices had no provisions for catering to peripherals with a specific throughput that MUST be available under all conditions, e.g. even if the host computer is unusually busy, or if other peripheral devices on the same bus also raise high demands. USB was designed to handle as much data as it could, given the demands from all attached devices and the availability of CPU cycles and memory from its host device (PC or whatever). It was designed to "fail gracefully" when those demands exceeded the available bandwidth, so that if circumstances didn't allow it to convey certain information, it would carry on without locking up or requiring user intervention. To put it another way, it was designed to conceal its failures rather than communicate them.

For a number of years most high-quality professional audio equipment that was designed for connection to PCs used proprietary option cards that plugged in to the host computer's motherboard. That was expensive and required a lot of extra development time, not to mention the inconvenience of opening one's computer to plug the card in (and the fact that laptops were thus ruled out). Clearly USB, FireWire and other similar protocols would be preferable if/when they were up to the task. There was enormous market pressure to switch over to them, ready or not.

Fast forward to today; I've got ~15 USB 2.x or 3.x devices attached to my PC, many via two outboard "hubs". There are at least four independent host devices on the motherboard of this computer. So each hub is subject to contention among the devices attached to it, over which I have no control nor even any way of monitoring; each bus is subject to contention among the devices attached to it, over which I have no control nor even any way of monitoring, and each host device on the motherboard, likewise. The Windows device manager doesn't identify these peripherals in a useful way nor show the overall layout of hosts vs. peripherals to let me balance the loads among the available buses. Maybe I have always had 20 times more available bandwidth as I have ever needed; maybe internal buffering on the peripheral side is always enough to get through the rough spots that I happen to have; maybe on a good day everything has sufficient margin, but during certain tasks it doesn't. I couldn't tell you, because the system is designed to keep on functioning at a reduced level of performance rather than complain. And reduced performance in this case means ignoring a peripheral that is asking for attention that can't be granted at that moment.

Some of the devices that I attach via USB include disk drives. When copying files to and from them, the equipment and the operating system obviously follow strategies to make sure that bytes aren't dropped. But as users we can see that the data transfer speed is allowed to vary during such operations. When writing large numbers of small files to a drive, for example (especially a spindle drive rather than an SSD), everything slows way, way down as it must.

Now maybe in the meantime the USB standard has been developed in exactly the needed direction, so that a bus will configure itself when a certain class of peripheral device is attached, pre-allocating host resources on a basis that guarantees uninterrupted, error-free isochronous data transfer. There are apparently some elements of that in effect nowadays--but what do they add up to in practice with typical, current implementations, or with the arrangement that I have on my PC today? I don't happen to know the answer to that, other than "all the other kids are doing it, so it must be OK." And I'm just pointing out that yeah, maybe--but it's really strange not to know or even to have any way of knowing.

--best regards
« Last Edit: August 29, 2020, 08:57:21 AM by DSatz »
music > microphones > a recorder of some sort

Offline fotoralf.be

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Re: miniDSP AmbiMIK-1 Ambisonic Mic
« Reply #31 on: August 29, 2020, 08:54:59 AM »
I've got ~15 USB 2.x or 3.x devices attached to my PC, many via two outboard "hubs".

And this is the computer you carry along for your recordings?

Ralf
Photography and industrial audioscapes from Western Europe. - Sound examples: http://aporee.org/maps/projects/fotoralf - Blog (German): http://the-real-fotoralf.blogspot.com

Offline DSatz

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Re: miniDSP AmbiMIK-1 Ambisonic Mic
« Reply #32 on: August 29, 2020, 09:03:30 AM »
Hi, Ralf. I stopped using a laptop for location recording about 15 years ago. At the time I was using a PCMCIA card that accepted 16-bit 44.1 kHz S/P-DIF input. It seemed to work, at least the way that I was using it. I was taken aback when very suddenly the PCMCIA (or "PC Card") interface was dropped by the industry like a hot potato.

But your question underlines the point--you wouldn't (in your right mind) attach any unnecessary peripherals to a computer that you want to use for recording, nor run any other programs at the same time, etc., because PCs (and Macs) aren't designed for "privileged" real-time data input.

--best regards
« Last Edit: August 29, 2020, 09:05:14 AM by DSatz »
music > microphones > a recorder of some sort

Offline fotoralf.be

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Re: miniDSP AmbiMIK-1 Ambisonic Mic
« Reply #33 on: August 29, 2020, 09:19:24 AM »
Hi, Ralf. I stopped using a laptop for location recording about 15 years ago. At the time I was using a PCMCIA card that accepted 16-bit 44.1 kHz S/P-DIF input. It seemed to work, at least the way that I was using it.

Around ten years ago, I've used a EMU 1616M audio interface connected via a PCI Express card to what was then a top-of-the line laptop and that was the first and last time I've had hickups and dropouts while recording. 

Since, I've been using various USB and Firewire audio interfaces and never experienced any problems of the kind you appear to be afraid of. 

Looking at the bandwidths of USB 2, 3, and C as well as Firewire, Thunderbolt, and whatever might be next week's dernier cri, a 'privileged' real-time input just isn't a topic anymore.   

Ralf
Photography and industrial audioscapes from Western Europe. - Sound examples: http://aporee.org/maps/projects/fotoralf - Blog (German): http://the-real-fotoralf.blogspot.com

Offline WiFiJeff

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Re: miniDSP AmbiMIK-1 Ambisonic Mic
« Reply #34 on: August 29, 2020, 03:10:00 PM »
The reason I have been playing around with the dedicated new ZR-1 recorder (which connects to the 19 channel ZM-1 mic also by USB connection) is that the dedicated Windows 10 micro-computer I was using, the Ockel Sirius A Pro, is fanless and deals with excess heat by slowing down processing speed.  Usually this has not been a problem, but once or twice it seems to have been the root of a recording error.  The slightly larger Chuwi Microbook I tried has a fan which is a bit too noisy.  Using a bigger, more capable, laptop is no advantage over the dedicated recorder for portability.  My problems do not seem in any way USB related, as far as I can tell.

Jeff

Offline DSatz

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Re: miniDSP AmbiMIK-1 Ambisonic Mic
« Reply #35 on: August 29, 2020, 03:13:32 PM »
Throughput rates, as I said, aren't my main concern; clearly those have gone through the roof, compared to the early days. It's the fact that the host isn't obliged to pay any attention whatsoever to a given peripheral in a given interval of time, if the load on the host during that interval is too severe for whatever reason.

As far as I can see (though admittedly I didn't dig deep--and deep in this case would be very deep), the facility for isochronous transfer in USB is on a strictly frame-by-frame basis. In other words the system can't drop bytes within frames, but entire frames can be dropped unless there's some additional protocol in place to cache and resend them if they're not received. Any mechanisms for guaranteed delivery of data, or clear indications of when that delivery fails, are completely foreign to the USB protocol.

I'm not arguing against the use of USB peripherals for audio; I'm just saying that I've always been wary of them. The development of such devices came from the consumer side, and there was a memorable period of configuration and performance headaches with such devices, which soured me on them. And I'm unaware of any fundamental change whereby a certain line was crossed, and now we can tell for sure that things are working 100% OK. I prefer protocols and connection methods that are designed from the start to work with a professional level of reliability, rather than being designed to try and get by without their failures being noticed--even though I'm sure they've become "probably OK to use" due to the gradual increase in host speed over the years, i.e. Moore's Law.

Admittedly I am an old curmudgeon (and was already a curmudgeon when I was younger; it's awkward being a teenage curmudgeon, let me tell you!), and I have a big resentment about the number of different, incompatible USB plugs, adapters and cables that I have to keep around--which I realize is the result of the the USB standards group's sincere best efforts. To say more would be to launch into a general criticism of the times we live in ...
« Last Edit: August 29, 2020, 03:25:14 PM by DSatz »
music > microphones > a recorder of some sort

Offline fotoralf.be

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Re: miniDSP AmbiMIK-1 Ambisonic Mic
« Reply #36 on: August 29, 2020, 03:25:09 PM »
Then by all means stay away from recording with computers in general and especially under Windoze.

Ralf
Photography and industrial audioscapes from Western Europe. - Sound examples: http://aporee.org/maps/projects/fotoralf - Blog (German): http://the-real-fotoralf.blogspot.com

Offline DSatz

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Re: miniDSP AmbiMIK-1 Ambisonic Mic
« Reply #37 on: August 29, 2020, 03:41:12 PM »
Ralf, I know that you're mocking me to some extent, but I'll cheerfully go along with it. I never record directly to a computer via USB for exactly the reason I've given in this thread.

I realize that I left out a total horror show example of an experience I had that is directly "on point"--a completely ruined three-track recording session (to a laptop computer via a four-channel USB interface--"Quattro Pro" from Midiman / M Audio) that I didn't realize was ruined until I got home and tried to edit the files. There were increasingly large blocks of skipped samples after the first ~20 minutes or so of each file. I'd put that experience out of my mind, I guess. Nothing beyond those first ~20 minutes was retrievable. It was the worst technical failure in my fifty years of recording, unless I'm forgetting something else.

And OK, if there had to be a 20-minute limitation, if I'd known about it I could have worked within it. It would have been extremely awkward and frustrating, but the entire session wouldn't have been lost.  I had tested the equipment beforehand, of course, but it never occurred to me that there might be an increasing problem with longer takes, so my testing was limited to samples of a minute or two.

I'm currently in the midst of a huge archiving project, but all the real-time audio work takes place on audio equipment, ending up with a digital audio recorder that is nothing more and does nothing more. Then the stored result is physically moved over to a computer for final editing and processing. That makes the most sense to me--even if it's 99.x% sure that it would be OK to record directly to the computer and save the physical transfer of the stored files.

Also, I'm perfectly well aware that inside some of my recording equipment, microprocessors are doing digital signal processing. But they are designed so that the number of samples out = the number of samples in, with no wishing, hoping or begging involved.

--best regards
« Last Edit: August 29, 2020, 09:47:13 PM by DSatz »
music > microphones > a recorder of some sort

Offline fotoralf.be

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Re: miniDSP AmbiMIK-1 Ambisonic Mic
« Reply #38 on: August 29, 2020, 03:50:53 PM »
If this saves your peace of mind then you're certainly welcome to it. And I'm being totally serious here.

Ralf
Photography and industrial audioscapes from Western Europe. - Sound examples: http://aporee.org/maps/projects/fotoralf - Blog (German): http://the-real-fotoralf.blogspot.com

Offline illconditioned

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Re: miniDSP AmbiMIK-1 Ambisonic Mic
« Reply #39 on: August 30, 2020, 12:49:27 AM »
I too prefer "standalone" recorders.
If you don't mind running off AC power, the Behringer XR series of mixers works very well.
You can do a full mix, and also record either stereo or multi track.  Control remotely using a phone, iPad or laptop computer.
I too have played with laptops but always rely on standalone devices.  The last thing I need is boot or update problems at a live gig.
  Richard

Please DO NOT mail me with tech questions.  I will try to answer in the forums when I get a chance.  Thanks.

Sample recordings at: http://www.soundmann.com.

Offline voltronic

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Re: miniDSP AmbiMIK-1 Ambisonic Mic
« Reply #40 on: August 30, 2020, 08:11:14 AM »
The reason I have been playing around with the dedicated new ZR-1 recorder (which connects to the 19 channel ZM-1 mic also by USB connection) is that the dedicated Windows 10 micro-computer I was using, the Ockel Sirius A Pro, is fanless and deals with excess heat by slowing down processing speed.  Usually this has not been a problem, but once or twice it seems to have been the root of a recording error.  The slightly larger Chuwi Microbook I tried has a fan which is a bit too noisy.  Using a bigger, more capable, laptop is no advantage over the dedicated recorder for portability.  My problems do not seem in any way USB related, as far as I can tell.

Jeff

IMHO, you need to get away from systems like that if you want quiet paired with solid performance.

I have been a quiet PC building enthusiast for many years now, back when it was relatively difficult to do so.  Now, you can make yourself something that is vanishingly quiet until it is under heavy load.  You start with a quality case that has thick, well-damped panels, and add large, low-RPM fans.  Then it's a matter of using a large CPU cooler with a large fan, and you can then set all of your power-saving settings in Windows to "high performance".

Here is my current system.  The video card fans and PSU fan stay off until there is heavy load, and the system and CPU fans are extremely quiet, staying under 500 RPM at low load.

FYI, I do NOT recommend liquid cooling.  Besides all of the hassle with those setups, they often require more fans than air cooling in order to get good flow through the radiator.  More importantly, the best air CPU coolers (Scythe, Noctua, etc.) actually outperform most liquid setups now.
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Offline fotoralf.be

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Re: miniDSP AmbiMIK-1 Ambisonic Mic
« Reply #41 on: August 30, 2020, 08:52:34 AM »
I haven't been using Windows for the last two decades. Is there still the eternal fight for taming interrupts and the dark deamons in the underworld of the registry to get things running without hickups and conflicts?

Ralf
Photography and industrial audioscapes from Western Europe. - Sound examples: http://aporee.org/maps/projects/fotoralf - Blog (German): http://the-real-fotoralf.blogspot.com

Offline voltronic

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Re: miniDSP AmbiMIK-1 Ambisonic Mic
« Reply #42 on: August 30, 2020, 01:13:33 PM »
I haven't been using Windows for the last two decades. Is there still the eternal fight for taming interrupts and the dark deamons in the underworld of the registry to get things running without hickups and conflicts?

Ralf

Ha!  I remember those days.  I used to be a PC repair tech 20-25 years ago, and I had IRQ numbers and memory addresses memorized for common ports and hardware.

Thankfully, those days are long over.  No more manually resolving IRQ conflicts, and I rarely delve into the registry unless there is a very unique case.  Today, Windows "just works" for the most part, as the Mac ads used to say.  Actually, it tends to be a better choice than Mac for things like music production nowadays, as some of the most recent OSX updates have rendered some popular pro audio apps unusable, because of breaking the audio subsystem, removing 32-bit app capability, and such.

The biggest point against Windows 10 is that it is quite invasive of user privacy by default.  Fortunately, they have made it easier to disable most of that telemetry in recent versions.  I also run this on all of my systems to get rid of a lot of the pre-installed crap I don't use.
https://github.com/Sycnex/Windows10Debloater
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Offline fotoralf.be

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Re: miniDSP AmbiMIK-1 Ambisonic Mic
« Reply #43 on: August 30, 2020, 04:06:29 PM »
Actually, it tends to be a better choice than Mac for things like music production nowadays, as some of the most recent OSX updates have rendered some popular pro audio apps unusable, because of breaking the audio subsystem, removing 32-bit app capability, and such.

*sigh*

I know. I'll be stuck with Mojave for years to come because I'm not ready to discard perfectly functioning hardware like my MOTU traveler Mk3.

Ralf
Photography and industrial audioscapes from Western Europe. - Sound examples: http://aporee.org/maps/projects/fotoralf - Blog (German): http://the-real-fotoralf.blogspot.com

Offline voltronic

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Re: miniDSP AmbiMIK-1 Ambisonic Mic
« Reply #44 on: August 30, 2020, 05:25:54 PM »
Actually, it tends to be a better choice than Mac for things like music production nowadays, as some of the most recent OSX updates have rendered some popular pro audio apps unusable, because of breaking the audio subsystem, removing 32-bit app capability, and such.

*sigh*

I know. I'll be stuck with Mojave for years to come because I'm not ready to discard perfectly functioning hardware like my MOTU traveler Mk3.

Ralf

It's really sad to see.  Apple used to be the platform for content creators.  Now it seems they no longer care about that segment of their user base.  The best way out from a customer standpoint would be if Apple stopped making desktops and laptops, and went 100% in on iOS devices.  Then, they could sell or license OSX to hardware companies who could build dedicated systems. 

Of course, this will never happen.
DPA 4061 | Line Audio CM3 | Naiant X-Q | AT 853  //  Naiant PFAs | Shure FP24  //  Zoom F6 | Sony PCM-M10
MOTU M2 // KRK Rokit RP5 // Sennheiser HD 650

Team Line Audio

 

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