Is this an appropriate place...

[SMcK]

...to make suggestions regarding Rehearsal Assistant?

Thanks
-Scott

[Stjepan Rajko]

Totally - your suggestions would be most welcome here.

Best,

Stjepan

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[SMcK]

Here goes...

Keeping in mind I’ve only used this program a few times, and apologies
if this is an issue you’ve already considered and addressed…

I’ve used Rehearsal Assistant mostly to record wav files of musical
ideas while singing and playing acoustic guitar into my Motorola
Droid. Those recordings have a somewhat unpleasant quality -- beyond
that which can be blamed on my own playing and singing. :)

I think the problem is that there’s a strong peak in the upper
midrange of the recording. This makes sense, as the microphone is
probably designed to emphasize those frequencies for phone calls
because they are crucial to intelligibility. For recording music, I
wonder whether it would be possible, as part of the program, to
digitally re-equalize the recording to eliminate that peak – to render
the recording “flat” (in music-recording-speak). Professional sound
people have equipment that plays pink or white noise into a room or
recording system, and analyzes the signal coming back to them to
determine which frequencies are being emphasized or deemphasized by
the room or system. They can then take steps to counteract the
emphasis and flatten the signal being heard or recorded. If you have
access to this equipment you could record some pink noise on, say, a
Moto Droid, analyze it, and have Rehearsal Assistant tweak it to sound
more flat.

A lower-tech alternative would be to have someone with good ears
record something, digitally re-equalize it to sound more flat, and
tell you what frequencies he or she changed.

A complicating factor to this would be that the equalization profiles
could be significantly different between phones, though I suspect all
of them will have an upper mid-range peak.

-Scott

On Jan 4, 8:30 pm, Stjepan Rajko <stje...@urbanstew.org> wrote:
> Totally - your suggestions would be most welcome here.
>
> Best,
>
> Stjepan
>
>
>
> On Mon, Jan 4, 2010 at 3:37 PM, SMcK <npi...@gmail.com> wrote:
>
> > ...to make suggestions regarding Rehearsal Assistant?
>
> > Thanks
> > -Scott
>
> > --
>
> > You received this message because you are subscribed to the Google Groups
> > "urbanSTEW" group.
> > To post to this group, send email to urba...@googlegroups.com.
> > To unsubscribe from this group, send email to

> > urbanstew+...@googlegroups.com<urbanstew%2Bunsubscribe@googlegroups­.com>

> > .
> > For more options, visit this group at

> >http://groups.google.com/group/urbanstew?hl=en.- Hide quoted text -
>
> - Show quoted text -

[Stjepan Rajko]

Hi Scott,

Thank you for your suggestion.  We've been discussing taking Rehearsal Assistant into the domain of more professional recording, and for that what you're suggesting would be a great addition.  We will definitely consider it.  We're yet to do tests on transforming the signal into the frequency domain on the device (so it could be equalized) - once we get to that we'll know a little more about how feasible it would be to do this kind of processing as part of the app.

Another thing we are curious about is the use of external microphones for recording - but I am yet to hear back reports that this works successfully with Rehearsal Assistant (or that it doesn't work, for that matter).  Perhaps a better mic would help with the problem you are experiencing, although it would make the complete system more cumbersome.

Thanks again, and if you have any other suggestions or comments, please let us know!

Best,

Stjepan

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[SMcK]

I would think a better, or different, microphone would be an easy
solution, though I'm not sure how the signal would get into the
phone. Maybe via Bluetooth?...

-Scott

> > > >http://groups.google.com/group/urbanstew?hl=en.-Hide quoted text -

[Stjepan Rajko]

On Tue, Jan 5, 2010 at 2:45 PM, SMcK <npi...@gmail.com> wrote:

I would think a better, or different, microphone would be an easy
solution, though I'm not sure how the signal would get into the
phone.  Maybe via Bluetooth?...

Yeah, I think that should work.  I just found a system that seems a bit blown up in price, but basically allows you to connect any XLR mic to a portable pre-amp and send out the signal via bluetooth:

http://www.pro-sound.com/I/SJKBLUE.html

If you find something that seems like a good and affordable solution please let us know (especially if you test it with Rehearsal Assistant and it works :-)... well, if it doesn't work it would be good to know as well).

Best,

Stjepan

[Stjepan Rajko]

On Tue, Jan 5, 2010 at 2:45 PM, SMcK <npi...@gmail.com> wrote:

I would think a better, or different, microphone would be an easy
solution, though I'm not sure how the signal would get into the
phone.  Maybe via Bluetooth?...

Another possible solution might be something like this:

http://store.androidcommunity.com/content/accessories/11-75--4401.htm

, which allows you to connect a mic to the phone via the ExtUSB connection. It's geared more towards headphones/headsets, so it expects the mic input as part of a 3-ring 3.5mm (or 2.5mm) jack, so you'd probably need an adapter.

Not sure what the quality could be going this route though...

Best,

Stjepan

[Robert Esler]

Just a few comments on this thread.  I'm not a bluetooth expert so I'm not sure as of yet whether bluetooth has invested in the appropriate bandwidth/codec hardware to get CD quality audio from a mic pre-amp device.  The specs on the JK audio device do not reveal what the actual bandwidth would be, they just say "full bandwidth" but it is unclear whether they mean for voice or the full audio spectrum.  (they do say "Headphone mode: 30Hz - 17 kHz" but does this apply to the recorded audio?)

  Right now apt-x is an impressive codec for bluetooth and is relatively lossless (4:1 but at CD quality), though are there products that support this in their audio hardware?  That is what I don't know.  If not now then probably soon, but at a high price I'm sure. 

  Moreover, the JK audio product does not have phantom power so any high-end condenser would not work.  A low-Z dynamic microphone could achieve the full spectrum quality the user is looking for, but that could only be determined through trial and error.  Keep in mind the JK audio product is labeled as an interview tool.  So for music/field recording it may not be enough data.  

   I completely understand what the user is looking to do, but my guess is that Bluetooth is not ready yet for field recording unless there is hardware using a near lossless streaming format.  

   Stjepan, does Rehearsal Assistant support an audio codec at 44.1K, 16 bit?  And does it have capability for apt-X format?  http://www.aptx.com/Technology-Portfolio/apt-X-Bluetooth.aspx

   If so then RA could be the answer for field recordists, and/or could include a plug-in or alternate packet for such use, just as long as the hardware is in place.  

   For the price, the JK audio bluetooth audio device looks like a risk, but I would be interested to hear if anyone has tried it.  

- Rob

Robert Esler http://www.robertesler.com/

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Date: Fri, 8 Jan 2010 21:24:15 -0700
Subject: Re: [urbanSTEW] Re: Is this an appropriate place...
From: stj...@urbanstew.org
To: urba...@googlegroups.com

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[Stjepan Rajko]

On Sat, Jan 9, 2010 at 12:59 PM, Robert Esler <rw...@hotmail.com> wrote:

   Stjepan, does Rehearsal Assistant support an audio codec at 44.1K, 16 bit?  And does it have capability for apt-X format?  http://www.aptx.com/Technology-Portfolio/apt-X-Bluetooth.aspx

Rehearsal Assistant can record uncompressed WAV audio at 44.1K, 16 bit (I'm pretty sure it's 16 bit, don't have time to check right now).  After that it could conceivably be transcoded to a different format (real time encoding as the recording is made is tricky because the processing power on the device is limited), but this is something we haven't tested much.  Transcoding to ogg vorbis is on my list of things to try.  I'll take a look at apt-X.

Best,

Stjepan

[SMcK]

On Jan 11, 9:38 pm, Stjepan Rajko <stje...@urbanstew.org> wrote:

According to my audio playback program (ancient Cool Edit '96 demo)
the wav file is indeed 44.1, 16 bit.

For my purposes it would really be handy to just use the onboard mic.
If I had to use an external USB mic it wouldn't need to be great
quality. I've been pretty happy with recordings made with old Radio
Shack PZM mics and run-of-the-mill dynamics. I know that there are
USB mics out there, both condenser and dynamic. I suspect most USB
condensors are built to use phantom power from the USB port, but I
there may be some that can run off their own on-board batteries.

I still suspect it wouldn't be terribly difficult to to write some
code to re-EQ the recording to compensate for peaks imposed by the
cellphone mic. If I had my home recording computer up and running I
would record something with the phone, re-EQ it to taste by ear and
make some suggestions as to how to tweak the signal to flatten it
some. Of course I could also just do that, post-recording, with *all*
my phone recordings, thereby saving folks the headache of writing code
to EQ it on the phone. Still, I can imagine a Flatten Feature might
make RA more attractive to paying customers.

Having said all the above, I made my initial comments based on a very
few voice and acoustic guitar recordings. Maybe before anyone takes
on any work based on my opinion, I should do some more recording, or
some other music recordists should chime in.

Cheers,
-Scott