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Gear / Technical Help => Ask The Tapers => Topic started by: Josephine on June 03, 2006, 05:01:16 PM

Title: Brickwalling
Post by: Josephine on June 03, 2006, 05:01:16 PM
A few weeks back, I recorded ( with my SP-CMC-8 > SP-SPSB-6 rig ) a really loud show.  Most of the recording came out nice, but unfortunately there are places in the recording that are all distorted as a result of my levels being too high and the show being too damn loud.  The house's mix had the bass so high, my nose and ears were actually itching from the vibration.  The mics just couldn't handle it.  I suppose normally I would just write it up as a loss, but it's a real special show to me and I am certain mine is the only recording. 

I realize there is no way to repair brickwalling, but is there something I can do in post to minimize its negative effect?   Can someone tell me how to make a bad situation a bit better?  (I use Sound Forge to edit.)

Title: Re: Brickwalling
Post by: tapers_are_geeks on June 03, 2006, 05:17:50 PM
run Normalize and lower the db until it's between -6 and-12. after that you'll need to run the Noise Reduction feature.. if the bass is muddy you need to go into EQ settings and choose the roll-off feature below 120hz.... what recording/show is it?
Title: Re: Brickwalling
Post by: Josephine on June 03, 2006, 05:22:35 PM
run Normalize and lower the db until it's between -6 and-12. after that you'll need to run the Noise Reduction feature.. if the bass is muddy you need to go into EQ settings and choose the roll-off feature below 120hz.... what recording/show is it?

Do I apply this to the entire recording, or just to the affected portions?
It's a Thorogood recording.
Thanks for the help.  :)
Title: Re: Brickwalling
Post by: tapers_are_geeks on June 03, 2006, 05:28:36 PM
i would do it to the entire recording. you can do parts if you like although there will be a fluctuation in the sound playback when done.

basically i would do it in this order
EQ roll-off below 120hz>Normalize>noise reduction

i have an sp-pre as well and i run mine at 160hz roll-off. at this frequency i dont have to do any post eq editing
Title: Re: Brickwalling
Post by: Josephine on June 03, 2006, 05:33:55 PM
I was running at 107hz.   It was not enough.   :(
Thanks for the advice . . . appreciate it.
Title: Re: Brickwalling
Post by: pmonk66 on June 03, 2006, 05:40:18 PM
Wow - I just ran into the same problem. Taped Rose Hill Drive last night at CBGB's and I knew I was in trouble from the beginning. Loudest concert I've ever ben too! Even the guitarist was complaining that the bass was too loud. My ears are still ringing!
Title: Re: Brickwalling
Post by: tapers_are_geeks on June 03, 2006, 06:16:59 PM
you can always use a high roll-off feature from the sp-pre. set it high cause you can always add bass post sound forge equing, but it's hard to remove the really deep mudd after the fact. you can try and try,but the more you roll it off post eq the more messy it well sound...i just leave mine on 160hz.

what kind of recorder are you using?
Title: Re: Brickwalling
Post by: Josephine on June 03, 2006, 06:22:52 PM
I usually run a different setup than the SP mics.  I have to admit, I'm not all too familiar with them or the battery box.
I had them running into my D100.
Next time, you can bet I will use a higher roll off setting.
I do have to say, though, that the bass was just unbelievably high at this show.
Title: Re: Brickwalling
Post by: nameloc01 on June 03, 2006, 07:03:08 PM
i have had a few like that. i just set my batt. box r/o to 195 hz pretty much all the time now,since i had nothing but excellent results.not sure what recording device you are using,on my hi-md i always go > line in vs. > mic in. mic in cant handle loud volumes
Title: Re: Brickwalling
Post by: bluegrass_brad on June 03, 2006, 08:04:18 PM
There is a "smooth" feature in SoundForge which can help a little bit.  You have to play with it a little though because if you use too much it begins to sound muffled.
Title: Re: Brickwalling
Post by: Brian Skalinder on June 03, 2006, 09:07:56 PM
run Normalize and lower the db until it's between -6 and-12. after that you'll need to run the Noise Reduction feature.. if the bass is muddy you need to go into EQ settings and choose the roll-off feature below 120hz.... what recording/show is it?

I understand toying around with HPF to achieve a better result, am unsure of how SF's NR feature works, but I don't understand the intent of dropping the levels to -6 to -12 dB.  Help me understand why and what this will accomplish and why?
Title: Re: Brickwalling
Post by: schoepsnbox on June 03, 2006, 09:19:13 PM
Josephine, why no schoeps? ???  Were you running line in or mic in?  Sorry to hear about the recording, hope your able to straighten it out.
Title: Re: Brickwalling
Post by: George on June 03, 2006, 09:37:20 PM
A few weeks back, I recorded ( with my SP-CMC-8 > SP-SPSB-6 rig ) a really loud show.  Most of the recording came out nice, but unfortunately there are places in the recording that are all distorted as a result of my levels being too high and the show being too damn loud.  The house's mix had the bass so high, my nose and ears were actually itching from the vibration.  The mics just couldn't handle it.  I suppose normally I would just write it up as a loss, but it's a real special show to me and I am certain mine is the only recording. 

I realize there is no way to repair brickwalling, but is there something I can do in post to minimize its negative effect?   Can someone tell me how to make a bad situation a bit better?  (I use Sound Forge to edit.)



I can't help you in terms of cleaning up the distortion.  My noobie understanding of distortion (ie. brickwalling) is that when its there, you can't get rid of it.   :(

For the future:

Get the mics modded for phantom power.  They terminated to mini xlr's, get a preamp that accepts mini xlr's and you are set.  My at853 rig consists of a sanjay-built preamp with mini xlr inputs and my iriver H140.  It's super stealthy.

Read this regarding using the bass roll off feature with an D100/M1:  http://taperssection.com/index.php?topic=46007.0
Title: Re: Brickwalling
Post by: Josephine on June 04, 2006, 02:36:35 PM
Josephine, why no schoeps? ???  Were you running line in or mic in?  Sorry to hear about the recording, hope your able to straighten it out.

The band and I go back a long ways.  In 25 years, not one of them has ever seen me in a hat. 
It's one thing wearing a dorky Kangol amongst strangers . . . . you get the idea.
I hated leaving the Schoeps at home, but felt I didn't have much choice.
The guys definitely would have wondered what was up with the hat and my unusually restricted movements.

I was running line in. 
Title: Re: Brickwalling
Post by: Jofa on June 04, 2006, 03:27:36 PM
I have always used the 69hz roll off > line in with my sp-cmc-8's. Never had any problem with brickwalling, maybe I'm just lucky?

/ R.
Title: Re: Brickwalling
Post by: nihilistic0 on June 05, 2006, 01:51:48 AM
I have always used the 69hz roll off > line in with my sp-cmc-8's. Never had any problem with brickwalling, maybe I'm just lucky?

/ R.

Most shows dont have enough bass to cause brickwalling.  Ive taped sp-cmc-4 > SP-SPSB-1 (no rolloff) And have experienced distortion only one time.  Taped tool, but there was a ridiculous amount of bass, causing said distortion.
Title: Re: Brickwalling
Post by: George on June 05, 2006, 08:40:29 AM
I'm not sure how effective bass roll off is in combating distortion.  I think its just the mics can't handle the high spl's and your better off getting them modded from phantom power.  It's a well known problem with the sp-cmc-4's at least.
Title: Re: Brickwalling
Post by: easy jim on June 06, 2006, 05:50:03 PM
I'm not sure how effective bass roll off is in combating distortion.  I think its just the mics can't handle the high spl's and your better off getting them modded from phantom power.  It's a well known problem with the sp-cmc-4's at least.

I would have to agree with the above Val.  If the spl's are too high for the mics, there is not much you can do about that, whether the bass was too dominant in the mix or not. 

I've found the Sound Prof's mics to already be really bright sounding, so I have never used the bass roll off options on my batt. box.  In fact, some of the nicest sounding tapes I've made with my Sound Prof's rig were incredibly loud shows with tons of bass (like a tape I made of Rush, not exactly a quiet band by any means, from the 2nd row in the 100s section at Shorline directly in front of one of the stacks).

But, on the other side of that, any engineer pushing out enough spl's from a system like that indoors to go over anything like 105 db should find a new career.  Too many engineers are either going deaf or suffering quite a bit of hearing loss, and that is often compounded by heavy duty earplugs which make them want to pump the gain even more to hear enough detail through their earplugs to mix properly. 

You should have been OK running line in with cmc8s through a batt box under any normal circumstance since the mics should be able to take spl's of 125 db when plugged through the batt box.  If the engineer had the system putting out more than 125 db, he should probably be sued for negligence (just like the Who was sued back in the 80s) for creating an environment that could cause excessive hearing damage.  From your description of how the sound made you feel, It is possible he was pushing it that high but not likely. More likely is that he had things around the 110 db threshold for the mics without the batt. box and that your battery is low or failing and thus not giving the mics enough power to handle the higher spl's.

How long has it been since you changed the battery in your battery box?
Title: Re: Brickwalling
Post by: Josephine on June 06, 2006, 06:06:28 PM
Hi James ~ Thanks for chiming in.  I appreciate all the info here. 

You know, it had been such a long time since I'd last used that battery box that I put a fresh one in for this show, so that wasn't the problem.  From what you've said, I'm wondering if my problems weren't just the result of running with my levels too high. 

I just transferred the show this afternoon.  Am looking at it now in Sound Forge.  Though it does seem to get better later in the show, the first part looks like one gigantic clip.   :'(

I've played around with a couple of the suggestions above . . . looks like the "smooth" plug-in might be my best option. 
BUT . . . I'm still open for suggestions (desparate is more like it).  :)
Title: Re: Brickwalling
Post by: easy jim on June 06, 2006, 06:30:16 PM
Well, maybe you are right then, and your levels were just too high.  We've all done that.  :-[ Good luck with the digital editing; I'm definitely more of a newbie with using the computer and cannot offer much help there.

If it were one of mine, I would probably try using a graphic EQ to start out and eliminate the low end frequencies one at a time to see if you can isolate which frequencies might be adjusted to create an EQ curve that will make a better sounding tape.