MOTM

I've never used an MPC4000 but I can offer you some general advise 
on recording the MOTM.
First off, there is a big advantage to having 24 bit versus 16 bit.
Secondly the sample rate is not nearly as important as the quality 
of the converters and most importantly the quality of the lowpass 
filters.
Thirdly the importance of clock stability cannot be overstated.  
Jitter can do some really weird stuff to your recording and you'll 
pull your hair out trying to figure out what is causing it.
There is nothing wrong with recording at 44.1Khz or 48Khz if your 
converters and filters are high quality.  I use Apogee converters 
almost exclusively.  I almost always record at 44.1Khz, because my 
stuff is intended for CD.  There is no such thing as a perfect 
sample rate conversion from 48KHz or even 96KHz or 192kHz to 
44.1kHz.  With the right converters and filters, and a stable clock 
recording at 24 bit and 44.1Khz will certainly capture the nuances 
of the MOTM.  If you record at 24 bit and are going to convert to 16 
bit be sure and add some good high quality dither as the last step.
I never have added any EQ to the MOTM when recording either.  
Although I haven't tried using FIR filters, the typical IIR filter 
will mess with the phase relationship between the harmonics and can 
smear the sound.  To me the MOTM sounds best recorded straight in, 
with no compression or EQ, just a little attenuation.

> I almost always record at 44.1Khz, because my stuff is intended for CD.
> There is no such thing as a perfect sample rate conversion from 48KHz or even 96KHz or 192kHz to 44.1kHz.


How about recording at 88.2KHz or 176.4KHz, and downsampling to 44.1KHz if outputting for CD?

How does that sort of sample rate conversion work out, do you still have the same quality issues with 88.2/176.4 to 44.1 as 48/96/192 to 44.1?


Simon
Canberra
AUSTRALIA

----- Original Message -----

From: <simon@...>
To: <motm@yahoogroups.com>
Sent: Saturday, February 07, 2004 12:10 PM
Subject: Re: [motm] Re: MPC4000 sound quality for MOTM


> > I almost always record at 44.1Khz, because my stuff is intended for CD.
> > There is no such thing as a perfect sample rate conversion from 48KHz or
even 96KHz or 192kHz to 44.1kHz.
>
>
> How about recording at 88.2KHz or 176.4KHz, and downsampling to 44.1KHz if
outputting for CD?
>
> How does that sort of sample rate conversion work out, do you still have
the same quality issues with 88.2/176.4 to 44.1 as 48/96/192 to 44.1?
>
>
> Simon
> Canberra
> AUSTRALIA
>
There is no problem downconverting from 88.2Khz or 176.4Khz to 44.1kHz.  You
are either using every other sample or every fourth sample.  When converting
to lower frequencies that are not from higher integer multiples there must
be some interpolation which is where the error comes in.

I still am not a fan of higher sample rates.  Most higher sample rates sound
better because the lowpass filter is at a higher frequency so there are less
phase artifacts in the audible range, not because the sample rate is higher.
IMHO there is no useful information contained in the sound above 20Khz
because you can't hear it. What you don't hear on higher sampling rates is
the high end phase smear caused by the filters in the converters.  The
higher rates make the sound seem to have more air or to be crisper, but
again this is just the lack of phase smear.

At 4:50 PM +0000 2/7/04, paulhaneberg wrote:
>I've never used an MPC4000 but I can offer you some general advise
>on recording the MOTM.
>First off, there is a big advantage to having 24 bit versus 16 bit.
>Secondly the sample rate is not nearly as important as the quality
>of the converters and most importantly the quality of the lowpass
>filters.
>Thirdly the importance of clock stability cannot be overstated. 
>Jitter can do some really weird stuff to your recording and you'll
>pull your hair out trying to figure out what is causing it.
>There is nothing wrong with recording at 44.1Khz or 48Khz if your
>converters and filters are high quality.  I use Apogee converters
>almost exclusively.  I almost always record at 44.1Khz, because my
>stuff is intended for CD.  There is no such thing as a perfect
>sample rate conversion from 48KHz or even 96KHz or 192kHz to
>44.1kHz.  With the right converters and filters, and a stable clock
>recording at 24 bit and 44.1Khz will certainly capture the nuances
>of the MOTM.  If you record at 24 bit and are going to convert to 16
>bit be sure and add some good high quality dither as the last step.

I pretty much agree with everything Paul says here. I don't have 
Apogee converters, but I'm pretty happy with the Swissonic converters 
I use. I do everything at 44.1 for, I think the advantages of not 
having to do sample rate conversion outweigh the advantages of higher 
sample rates. Plus, I don't want to deal with the storage issues. 24 
bit is pretty essential, though.

>I never have added any EQ to the MOTM when recording either.

I've been recording the MOTM lately through a Radial JDV DI box-> 
Amek/Neve 9098 preamp for recording, with the EQ bypassed, and have 
been quite pleased with the results. I wish the MOTM had a balanced 
XLR master output module, I'm sure one could be built, then I 
wouldn't need the DI to convert the signal to balanced.

>Although I haven't tried using FIR filters, the typical IIR filter
>will mess with the phase relationship between the harmonics and can
>smear the sound.

I recently picked up Elemental Audio's Firium EQ plugin, which is 
FIR-based, and to my ears, it seems like the most transparent EQ I 
have. It's great for removing trouble frequencies without affecting 
the rest of the signal. I don't know the theory behind FIR, I just 
know this plugin seems to have minimal side effects on the signal.

>  To me the MOTM sounds best recorded straight in,
>with no compression or EQ, just a little attenuation.

Absolutely true, but I find that when I'm trying to get the MOTM to 
fit into mixes, especially when competing with other instruments, it 
can require EQ and compression to fit right against the other 
instruments.

On Feb 7, 2004, at 12:32 PM, Paul Haneberg wrote:
>  ----- Original Message -----
>  I still am not a fan of higher sample rates.  Most higher sample 
> rates sound
>  better because the lowpass filter is at a higher frequency so there 
> are less
>  phase artifacts in the audible range, not because the sample rate is 
> higher.
>  IMHO there is no useful information contained in the sound above 20Khz
>  because you can't hear it. What you don't hear on higher sampling 
> rates is
>  the high end phase smear caused by the filters in the converters.  The
>  higher rates make the sound seem to have more air or to be crisper, 
> but
>  again this is just the lack of phase smear.

Rupert Neve would disagree with you.  I went to a evening talk at my 
local pro audio shop where he talked about this subject.  He tells this 
story about a client he had when he was building consoles that was 
complaining about the new board he just got.  He couldn't tell what was 
wrong but something was really bugging him.  They checked out every 
component on the board and couldn't find anything wrong.  Then he 
figured out that the high end slop for this board was different than 
previous models.   Seems they rolled off the high end at a lower 
frequency than the earlier models.  The roll off was still above 
hearing range.

I can't remember the numbers but the roll off was way above our normal 
hearing range.  He is a strong believer that there is a lot of content 
up there were we can't hear that does seem to make a difference on the 
overall sound.

Having said that, my personal feeling is that it really depends on the 
material you work with.  Classical music with all the dynamic range and 
tonal timbers would seem to be content that would benefit from 192k 
sample rate.  For the music I produce and write, I really doubt that it 
would matter that much.  The other thing is that I'm not even close to 
being able to convert my studio to work with anything above 48k.  I 
also agree with you that the quality of the converters is the key 
factor.

- chris

On Feb 7, 2004, at 1:30 PM, Dave Trenkel wrote:
>  I've been recording the MOTM lately through a Radial JDV DI box->
>  Amek/Neve 9098 preamp for recording, with the EQ bypassed, and have
>  been quite pleased with the results. I wish the MOTM had a balanced
>  XLR master output module, I'm sure one could be built, then I
>  wouldn't need the DI to convert the signal to balanced.

Hey, I have that same preamp.  Mine has a DI jack and switch on the 
front.  I run everything I can through that preamp.  Makes everything 
sound good.

- chris