Mixer channel clips too easily
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Posted on Feb 14, 2005 07:48 pm
Diamond Joe
Member Since: Feb 14, 2005
Hi Guys,
I'm new to HRC but I have a question I'm hoping someone can help me answer - you all seem like a clever bunch :-)
I have an old Soundcraft 200b mixer; the manual says that I should remove a specified jumper on each input channel's PCB when using -10dbV unbalanced signals. As all my samplers and synths outputs operate at -10db and have unbalanced connections I am using unbalanced cables and have removed the jumpers as suggested. When I do so the signal seems to be too hot and most channels clip if the tiniest amount of channel gain is used. I can't help but think that it should be the other way around and the jumper should be left on for -10dbV use, and removed for +4dbu. Could this just be a misprint? Earlier in the document, on page 4, it ALMOST seems to say the opposite when it suggests adding push-on jumpers to alternate between the two levels.
This information is printed at the top of page 27 on the following document:
www.soundcraft.com/downlo...r_guide_1-2.pdf
I could simply just use it the other way and put the jumpers back on, but I want to maximise my signal-to-noise ratio and fear that the other way I might need to raise the gain too much to bring it up to a workable level. Oh... and obviously the solution might be to leave it the way it is and not raise the gain, but when using the channel EQ to boost a frequency it naturally has the effect of raising the gain.
Help!
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Feb 14, 2005 07:58 pm welcome to HRC!!
are you positive your gear is runnin' at -10? as in documentation of anykind?
you might wanna try the +4 and see how that works
also changin your eq does not effect your INPUT gain only the OUTPUT level, start of by normalizing your board to unity (every fader and eq to zero) then set your input gain (trim), if you're dooin' drastic additve eq then pull the channel fader down some and vice versa, but try to keep the mains at unity, what is next in your signal chain after the mixer? i'll hafta get back to ya tommrow cuz i'm leavin' work right now...but a better detailed list of your gear will help...set it up in your profile and you'll never hafta tell ppl whatcha got....anyway good luck
later
wyd
Feb 14, 2005 07:59 pm try to hunt down where it is clipping, make sure you're positive you know exactly what gain stage you're clippin'
Feb 14, 2005 08:16 pm Thanks for your quick response.
Yeah, good point. I'm getting a little confused about where exactly the clipping is taking place. I was just going off the red LED lighting... but I guess I wasn't sure at what point it's been lighting. The manual reads:
"The Peak LED illuminates when the signal level at the insert point is 4db below clipping"
Which doesn't sound too bad I guess. Maybe I'm over-reacting... it should be OK to let it light-up and bit, it's mostly just on transients anyway. But... boosting the EQ does illumiate the LED, and that just confuses me even more :-(
I'm pretty certain that very few synths or samplers operate at +4dbu. Maybe just some of the high-end Kurzweil gear. Can anyone confirm?
Thanks for the advice, I have included a list of my gear.
Cheers.
Feb 15, 2005 12:21 pm ok i found a pic of your mixer and i think i see the red peak lights right at the top of the fader...so i'm gonna assume that it's indicating clipping right where it is (post eq) which is wierd but......again set your board to unity and if you're gonna record with eq (not recommended) you're gonna hafta compensate with the input trim (i guess) does the light stop clippin' if you pull the channel fader down? i've noticed when i record in sonar, the level i hear gooin' in is a bit quieter then the level i hear playin' back....i didn't see an audio interface, so i'm gonna assume you are using a stock card...this could be the weak link in your chain (cuz you defenitaly have some sweet keyboards!!) when you arm the track in sonar, is it showing clipping at the EXACT same time your mixer clips? if not you're not at unity somewhere, every clip light you have should light up at the same time (my personal rule when gain staging).....and i'm pretty sure your board is all analogue so yeah hittin' the peaks every once and a while (<8 times per song) is okay but i wouldn't risk it myself, transients are very important with percussion and stuff like that. ummmm i'm not sure if i gave you any useful info or not, but keep me posted.
peace
wyd
Feb 15, 2005 05:36 pm Thanks again for taking the time to look into this for me wyd. I can't tell you how much I appreciate it.
The weird thing is that the LED lights even with the fader all the way down, so it must be clipping at the input, yet post EQ (?!?)
I forgot to include that I'm using the M-Audio Delta 66 Omni. Maybe I should tell you exactly the way I've been working. Each synth or sampler goes line-in to it's own channel on the mixer. I also have two stereo input channels on the mixer taking outputs 1/2 and 3/4 from the Omni so I can use softsynths and software effects with the mix. Outboard effects are handled in the traditional manner with any of four send and returns. Everything gets mixed like that and when I'm happy I play the sequence through (ain't "no bounce to track" when using hardware), recording to a new audio track in Sonar which is set-up to take a stereo signal from the main-outs of the mixer.
So, the problem isn't Sonar/sound card/computer related at all and is soley about how the synths are interfacing with the mixer.
Incidently, there's a very interesting SOS article about why the sound going into your soundcard is lower than the sound coming out:
www.soundonsound.com/sos/...ba747b74a777139
Glad to hear you're using Sonar too... it's an awesome application; the workflow is unbeatable! Thanks too for your appreciation of my set-up. Let's just say that eBay is wonderful thing :-)
Feb 15, 2005 06:18 pm very good article, but i think i'm gonna hafta read it a few more times to really let it sink in...thanx for the link
