SD 442 Input Limiters.. Just an 'aggressive' sound when recording piano, or actual clipping?
Jason
I have a quick question regarding the 442 input limiters, & their
'sound' (if there is such a thing!) whilst recording piano, & would
appreciate any feedback 442-users can give me (thanks!).
I was recently asked to record some solo piano, & noticed that even
gentle pushing of the input-limiters created a mild but certainly
noticeable & unwanted 'clipping'-like sound (rather like the sound of
a soft overdrive, or like my Yamaha 02r's channel compressors if set
on a very short release-time (<30ms)). With the input-limiters
switched off, there was I admit the occasional red peak-light at the
input stage during the attack transients, but, IMHO, I thought the
whole point of the input limiters was to prevent this clipping
actually happening or at least being audible, particularly if only
mild clipping is occuring.
Has anyone else experienced this, or can anyone please try to
replicate it with a solo piano-recording if you have a spare moment?
(Note that it is source-independant, be it 48v condenser mic'd-up real
piano, line-level pre-recorded real piano from a CD, multisampled
piano playing back from my Mac etc etc.)
With speech - or a music-recording covering a wider frequency-range
- the 'clipping' sound is fairly masked & isn't that obvious (it
almost gives it a kind of 'broadcast', slightly 'driven' sound), but
with the piano, it sounds pretty horrible.
Joe at Sound Devices ("hi" if you're reading this Joe!) thinks my
(almost-new) mixer might have a problem, but I'm not so sure (it does
the same on all four channels), so I'm hoping to get some feedback
from you guys before I ship the thing from the UK to the States, only
to be told that 'the mixer is within specification'....
I'm guessing it's just a quirk of the 442, but if anyone can shed any
light, it would be very helpful!
Thanks - kind regards,
Jason
Soundhaspriority
"Jason" <jasonm...@googlemail.com> wrote in message
news:86d2f51a-937f-45df...@f36g2000hsa.googlegroups.com...
> Hi everyone :-)
>
> I have a quick question regarding the 442 input limiters, & their
> 'sound' (if there is such a thing!) whilst recording piano, & would
> appreciate any feedback 442-users can give me (thanks!).
>
> I was recently asked to record some solo piano, & noticed that even
> gentle pushing of the input-limiters created a mild but certainly
> noticeable & unwanted 'clipping'-like sound (rather like the sound of
> a soft overdrive, or like my Yamaha 02r's channel compressors if set
> on a very short release-time (<30ms)). With the input-limiters
> switched off, there was I admit the occasional red peak-light at the
> input stage during the attack transients, but, IMHO, I thought the
> whole point of the input limiters was to prevent this clipping
> actually happening or at least being audible, particularly if only
> mild clipping is occuring.
>
I have the 302, which I think is very similar to yours, and I have used it
on piano. I did not initially understand some aspects of the unit. The unit
has a couple of stages. If the gain (small black knob) is set high and the
trim (large gray knob) is set low, it is possible for the output stage to
overload before the input stage limiters operate.
Piano tends to make things clip. I modified my procedure by setting up so
the gain knob is in the middle range. The limiters are quite good, and I
have had no further problem with piano. It does not sound aggressive; it
just sounds good, with the slightly liquid quality typical of transformers.
Bob Morein
(310) 237-6511
Joe
Hi Jason ,maybe you are driving the trim gain to high thats why you
see the PEAK led light up...the peak led lights up when the input
signal is 3db from clipping .When I have my 442 gain structure
properly set , I find it almost impossible to clip......when the
''horrible '' sound happens , do you listen to PFL to hear how it
sounds ?
Could also be 2nd and 3rd harmonics from the piano causing
havoc...that has happened to me...it depends on mic placement in and
around the piano...maybe mic(s) are too close ?In what type of room
was the piano in...any glass surfaces around ? Close to a window
maybe ?
Joe ( no not the SD Joe ) .
tsvisser
to needing the limiter on piano, you are using way too much gain, or
have the gain structure incorrect. I generally leave the trim at zero
and then ride the trim as appropriate while tracking. If you are not
close mic'ing the piano, your peaks should probably be around -12 or
so... Piano could be a lot more dynamic than typical vox, depending on
what piece it is, so maybe even peaks a bit lower would be
appropriate, assuming that the pianist might rock out later during the
performance. If you are close mic'ing the piano, then it becomes
really so critical on the sensitivity of the mics being used, exact
placement, and how loud it will get. Average peaks could be like -26
or even lower in order to keep enough headroom for the loud passages.
The limiter is great for screaming actors, who occasionally catch you
by surprise, but for critical recoding of acoustic instruments, its
just not what the limiter was designed for. The only limiter should
be you manually riding the trims, and of course you would have to know
the music well in order to do this transparently.
Jason
Thanks for your very helpful replies - I really appreciate your
time.
I've got to go to hit the sack now (it's midnight here) as I've got an
early start, but will answer any questions properly tomorrow. In the
meantime, I've loaded up some sound files for you to have a listen to
(if you have time) if it helps highlight the problem:
http://www.hitsound.co.uk/442/
i) The ...."_LIMITER_OFF.mp3" file is to show the amount of channel
input clipping present (channel fader reduced a bit to prevent mix
buss clipping) without engaging the input-limiters.
ii) "_LIMITER_ON.mp3" is the same audio, same gain, but input-limiters
engaged. This file is the one exhibiting the sound I am talking about.
ii) "_RAW_PIANO_NO_CLIP.mp3" is the piano through the mixer, but
turned down to avoid clipping (so you can try running it through your
own 442 to see if it does the same thing as mine (but only if you find
yourself at a loose end of course) :-) ).
This recording is a multisampled piano by the way, playing back at
line level from my iPod. The result is similar when pushing the input-
limiters whether using this piano source, a balanced line-level
source, or phantom powered mics recording the real thing.
I fully recognise (& apologise) for what appears to be me running an
incorrect gain structure & asking academic and/or irrelevant
questions. You're absolutely right in that if I set the channel fader
to unity & adjust the channel gain until the signal is output-meter-
peaking at +20 vu, then no, I do not get any input clipping. However,
what I'm trying to establish with this thread is:
A) Piano or not, shouldn't mild use of the input limiters NOT induce
this kind of sonic anomaly?
B) Why is the 'clipping' sound noticeable with a piano signal, but not
so much with dialogue or a dance track for example?
C) Does your 442 sound the same as mine when driving the input
limiters (but not the output limiters) with this piano signal? (In so,
then it's me that's faulty, & not the 442 :-D .)
Thanks again!
Jason
Jason
I don't undersand why the input limiters sound like this, but the
output limiter sounds so transparent by comparison.... (If it's
because the channel's input is clipping before the input limiter cuts
in, then I don't understand why Sound Devices didn't set the input
limiter to cut in a little earlier/lower in the signal to avoid this
problem.)
Best,
Jason
Joe
Hi again Jason , just in case you dont know...or maybe you have read
the specs on the 442 manual already ?
The input limiters affect the outputs of the mic preamps only (trim
stage ) +18dBu threshold ( thats +18 dBu ! could you be that hot going
in... ? ) , 20:1 limiting ratio
1mS attack time ( could this part of your problem ? too slow .)
200 mS release time .
I still think you are driving the trim too hot though and proper gain
structure with the 442 can be tricky with soft to loud variations like
a piano .
Joe.
Charles Tomaras
Any chance you have your metering set for VU thinking its peak reading and
just aren't seeing the peaks that are killing you when you set your levels?
Soundhaspriority
90e29a8e-cadd-425a...@j22g2000hsf.googlegroups.com, "Joe"
<joec...@yahoo.ca> wrote:
I don't understand why MY technical assistance isn't appreciated.
"I don't really have a replacement career, it's a very gnawing thing."
Robert Morein
Dresher, PA
(310) 237-6511
(215) 646-4894
Jason
> On 6/25/08 5:14 AM, in article
I greatly appreciate everyone's help on this thread Robert, yours
included! :-)
(Sorry, I've just been very busy over the last few days & haven't had
chance to follow this thread up properly.)
Will try later tonight,
J
Soundhaspriority
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User-Agent: Microsoft-Entourage/12.10.0.080409
Date: Fri, 27 Jun 2008 15:18:59 +1000
Bob Morein
(310) 237-6511
Soundhaspriority
[snip]
I greatly appreciate everyone's help on this thread Robert, yours
included! :-)
(Sorry, I've just been very busy over the last few days & haven't had
chance to follow this thread up properly.)
Will try later tonight,
J
-----------------------------------------------------------------------------------------------
Jason,
You responded to a forgery by the Buzzard poopster. I just threw my two
cents into the pot, and I certainly didn't expect a thankyou note :)
But I am looking forward to hearing about the resolution.
All the best,
Bob Morein
(310) 237-6511