> I entered the loan request yesterday. I should hear back in about a
> week. I've had problems requesting "hi tech" books. I'm in a very rural
> area of Missouri ;}
I entered the loan request yesterday. I should hear back in about a
week. I've had problems requesting "hi tech" books. I'm in a very rural
area of Missouri ;}
Reply by Richard Owlett●July 3, 20172017-07-03
On 07/02/2017 11:29 AM, Les Cargill wrote:
> Richard Owlett wrote:
>>[snips by OP]
>> My voice recognition background is limited to reading end user
>> oriented literature a decade ago. At that time cost/benefit was
>> unacceptable. ...
>>
>> Box 1 - Microphone in, clean "hifi" digitized audio out Box 2 - The
>> rest of the system ;/
>>
>> Part of the reasoning behind my specification for Box 1 is to do
>> some blue sky experimentation with filters etc.
>>
>> The overall transfer function will yield a minimum of 40 thousand 16
>> bit (15 bits + sign) samples per second. Internally I assume
>> significantly higher numbers. I explicitly am leaving the latency
>> specification WIDE open. ...
>>
>> Comments on availability of consumer grade and price components I
>> should investigate? The goal being to decide what price/performance
>> trade-offs I wish to make.
>
> There is a small eternity of USB-linked D/A-A/D pairs out there.
> They are commonly referred to as "interfaces".
>
> That's the dominant portion of that market. It is USB, but the
> "Focusrite Scarlett 2i2 Studio" on Sweetwater should get you started.
<chuckle> That package is aimed at a *VERY* different market.
Someday I'm going discover a way to convey that my subject lines are
intended to be taken very literally and the body of my posts serve to
flesh out the fine details ;/
The software bundle would be useless as I use Linux only.
I wouldn't use the earphones as I would only listen to the audio to
proofread the speech recognizer output.
The microphone offered is physically unsuited for speech recognition.
One of the things I remember from my reading a decade ago [and presumed
still germane] the consistent mike placement is important to quality
recognition. I plan to satisfy that [and some other physical
constraints] with a headset mounted mike.
> [snip]
> Here is a forum post stating that a 2i2 works with one configuration
> change to a RasPi. I'd rather have a RasPi myself than a laptop if
> it's just for connectivity. Of course you can always use a laptop
> for that.
>
The computer's primary purpose is hosting the speech recognition software.
Reply by Les Cargill●July 2, 20172017-07-02
Richard Owlett wrote:
> My theory dates from 3 years towards a BSEE in the 60's. Real world
> experience focused on instrumentation ( 1 mV large signal, 10Hz very
> wide band ;) [Ever try to convince a fresh chemistry post doc that
> demanding a system gain-bandwidth product allowing measuring less
> than 1 electron per second wasn't reasonable?]
>
> My voice recognition background is limited to reading end user
> oriented literature a decade ago. At that time cost/benefit was
> unacceptable.
>
> Once again I'm interested. I have decided to split the system into
> two black boxes.
>
> Box 1 - Microphone in, clean "hifi" digitized audio out Box 2 - The
> rest of the system ;/
>
> This post is about Box 1.
>
> Part of the reasoning behind my specification for Box 1 is to some
> blue sky experimentation with filters etc.
>
> The overall transfer function will yield a minimum of 40 thousand 16
> bit (15 bits + sign) samples per second. Internally I assume
> significantly higher numbers. I explicitly am leaving the latency
> specification WIDE open. This black box may include a dedicated
> laptop computer for required processing power.
>
> Comments on availability of consumer grade and price components I
> should investigate? The goal being to decide what price/performance
> trade-offs I wish to make.
>
> Isn't retirement for doing what you couldn't?
>
There is a small eternity of USB-linked D/A-A/D pairs out there.
They are commonly referred to as "interfaces".
That's the dominant portion of that market. It is USB, but the
"Focusrite Scarlett 2i2 Studio" on Sweetwater should get you started.
It has what appears to be an inexpensive rebadge of the MXL SP1
microphone, a pair of phones and an interface.
There are others. Many others. This one is a market leader but it is
definitely built to a price point.
I have three of the SP1. They are all different. So quality is
inconsistent but all three are fine for voice. Sweetwater has a great
return policy so if it's broken, they'll get you one that isn't.
Here is a forum post stating that a 2i2 works with one configuration
change to a RasPi. I'd rather have a RasPi myself than a laptop if it's
just for connectivity. Of course you can always use a laptop for that.
https://raspberrypi.stackexchange.com/questions/13799/raspberry-pi-focusrite-scarlett-2i2
And here's networked Jack:
http://netjack.sourceforge.net/
( Jack is a Linux audio subsystem )
--
Les Cargill
Reply by Richard Owlett●July 1, 20172017-07-01
On 07/01/2017 10:03 AM, Steve Pope wrote:
> Tom Becker <gtbecker@rightime.com> wrote:
>
>> If you can use USB, there are many affordable quality USB
>> mic-preamp/audio-interface devices available today.
>>
>> As it happens, I just received a Behringer UMC404HD four-channel,
>> 44100-192000 sample rate, 16- or 24-bit sample for my microphone
>> development work, a very versatile device; it cost US$90 shipped.
>> https://www.sweetwater.com/store/detail/UMC404HD A two-channel
>> 192kHz/24-bit device is also available.
>> https://www.sweetwater.com/store/detail/UMC204HD
>>
>> Another device that might suit is the Art USBDualPre, a two-channel
>> device that only does 44100/48000 16-bit, for ~$75.
>> https://www.sweetwater.com/store/detail/USBDualPrePS
>>
>> If you want spend more, look at Sound Devices. You might consider the
>> USBPre2, for ~$900.
>> https://www.sounddevices.com/products/portable-audio-tools/usbpre2
>
> I know that people like Korg digitizers whose input can be a
> condensor mic and whose output can be FLAC or PCM on a mini (not micro)
> USB port.
>
I went to www.korg.com
Their page designers of the ilk who go for glitz over content and all
but guarantee I'll not give them the time of day. To wit in order to see
content you evidently need JavaScript enabled and don't have the common
courtesy to subject you enable it. Get the impression they hit a pet
peeve ;/
Thanks anyway for suggesting something to investigate.
> Of course it's overkill for speech and/or speaker recognition but
> you would then have a nice piece of audio equipment...
>
> Steve
>
I know that people like Korg digitizers whose input can be a
condensor mic and whose output can be FLAC or PCM on a mini (not micro)
USB port.
Of course it's overkill for speech and/or speaker recognition but
you would then have a nice piece of audio equipment...
Steve
Using audio built into the class of computers I own just just does not
allow me to adequately experiment with bit depth and sample rate. I'm
leaning towards something similar to a Behringer U-Phoria UMC204HD with
24-bit resolution and 192kHz sample rate. I don't know how successful
I'll be finding a microphone with comparable audio specifications in a
wearable headset.
There is a "not so hidden agenda" influencing my choices. DSP as a
subject did not exist when I was an EE student in early 60's. If
retirement isn't for learning, what use is it? <*GRIN*>
>
>> some blue sky experimentation with filters etc.
>
> You would have to decide on a frontend. A filterbank
> can be done in hardware. Bought as a vintage Reticon ASA16
> or patched up with SC-filters NAX262.
>
> MfG JRD
>
I couldn't find any information about those online. Besides, as you may
have noticed, I've already decided to do any processing in software not
hardware.
Thank you.
Reply by Rafael Deliano●June 29, 20172017-06-29
> My voice recognition background is limited to reading end user oriented
> literature a decade ago.
> Box 1 - Microphone in, clean "hifi" digitized audio out
/ This black box may include a dedicated laptop computer for
/ required processing power.
Most laptops have a mic-input that with software like WavePad
would get audio to file. But then you would have to do everything
in software. Thats "very flexible", usually non-realtime,
a bottomless pit in engineering time.
/ some blue sky experimentation with filters etc.
You would have to decide on a frontend. A filterbank
can be done in hardware. Bought as a vintage Reticon ASA16
or patched up with SC-filters NAX262.
MfG JRD
Reply by Christian Gollwitzer●June 28, 20172017-06-28
Am 28.06.17 um 16:54 schrieb Tom Becker:
> It sounds like you want to assemble a development platform, not develop a device from components that one might find a Sparkfun.com or Adafruit.com or Analog.com and Knowles.com.
>
> If that is so, you might be tempted to combine a microphone with the audio interface, i.e. a USB microphone like, IMO, Blue's ugliest of all mics, the Snowball, and many others. https://www.bhphotovideo.com/c/product/413696-REG/Blue_SNOWBALL_BUNDLE_TW_Snowball_USB_Condenser_Microphone.html You might search for "Podcast USB microphones" to find some reviews.
Another very versatile device of this sort is the Zoom H2n recorder.
It's around 150€, it has two stereo microphones, one in mid/side and one
in XY orientation. It can be used as a standalone recorder (writes to SD
cards), as a USB microphone, or as an audio interface (i.e. D/A of
another microphone to USB audio device). It can operate on batteries as
well as on USB power. The quality of the built-in microphones is
comparable to the Yeti USB mic, but it's less bulky.
Christian
Reply by Tom Becker●June 28, 20172017-06-28
It sounds like you want to assemble a development platform, not develop a device from components that one might find a Sparkfun.com or Adafruit.com or Analog.com and Knowles.com.
If that is so, you might be tempted to combine a microphone with the audio interface, i.e. a USB microphone like, IMO, Blue's ugliest of all mics, the Snowball, and many others. https://www.bhphotovideo.com/c/product/413696-REG/Blue_SNOWBALL_BUNDLE_TW_Snowball_USB_Condenser_Microphone.html You might search for "Podcast USB microphones" to find some reviews.
There are many cheap USB mics available; in my experience, cheap means noisy. If you will eventually be processing the audio, noise will complicate your task so spending a little more will perhaps put you on an easier path.
FWIW.
Tom