Topic: Brickwalling

[lsd2525]

Made a recording this weekend that I suspect was "brickwalled". Question: does brickwalling typically knock down the bass? I expected the distortion, but the recording is high-pitched and screechy, almost like I had a roll off engaged. Any ideas?

[StuStu]

High frequencies are often the cause the clipping. That could certainly explain the lack of bass and painful high end.

[lsd2525]

I need to go back to the drawing board. The directions from Sound professional says set recording level on deck for max. I guess do that and drive gain from preamp? I was kinda doing it 50/50 between deck and preamp box

[StuStu]

Exactly what gear were you running. I guess since you mentioned bass roll off and SP, one of their pres? Generally speaking, I want the most gain to come from my pre and use the recorder for tweaking the levels. Of course it does depend on what gear your using. If your using a high end pre and a handheld recorder, for example, you'll most likely get much cleaner gain, less noise, from the pre. Regardless of the specific gear, if you had your recorder cranked all the way up, I'd bet on that being your brick walling cause. I can't imagine why SP would recommend turning either the recorder OR the pre all the way up. That's asking for noise floor issues, clipping, etc. However, you did mention that you were balancing them out at 50/50.

[lsd2525]

AT853's into a Sound Professionals battery box/preamp (http://www.soundprofessionals.com/cgi-bin/gold/item/SP-PREAMP) into DR60. I've run the 853's into this deck using the AT8531 power supplies before many times without issue. Think I had it set on 22db gain.

I noticed that the levels on the deck never seemed to go up or down more than several db.

The only other thing I can thin of is that I was using a darktrain 2 mini xlr > 1/8 cable with the 4.7 mod to connect to the mics and give me the 1/8" that I needed to connect to the preamp. First time I've ever used this cable

[lsd2525]

AT853's into a Sound Professionals battery box/preamp (http://www.soundprofessionals.com/cgi-bin/gold/item/SP-PREAMP) into DR60. I've run the 853's into this deck using the AT8531 power supplies before many times without issue. Think I had it set on 22db gain.

I noticed that the levels on the deck never seemed to go up or down more than several db.

The only other thing I can thin of is that I was using a darktrain 2 mini xlr > 1/8 cable with the 4.7 mod to connect to the mics and give me the 1/8" that I needed to connect to the preamp. First time I've ever used this cable

In retrospect, I probably should have run with no gain. First time playing with this combo. Was running AT4041's on channels 1-2 so I didn't miss anything.

And after looking at the photograph of the box, the "high" setting is in the middle. That's what I had it on thinking it was "low". Sigh.

[StuStu]

Agreed, high setting is probably the cause. New set ups can sometimes throw us a curve ball. At least you seemed to have figured out the issue.

[lsd2525]

Well, I just need to try it out again to make sure that is the issue. The lack of bottom end is baffling me. And correct me if I'm wrong; it's the input on the recorder that I'm overloading, not the preamp itself, right?

I hope I can make this work; the form factor of the SP box is sweet, especially compared to lugging around two of the 8531 power modules. I ran into the DR60 just as a test run, will be running into an M10 for 007 work. On the instructions it actually says:

"1.   Set the recording level to the maximum setting in the ‘manual recording’ mode (some recorders are always in manual mode). The recording level should be at maximum for the best overall dynamic range and lowest signal to noise ratio.
2.   While monitoring a source signal, turn up the level control on the preamp (the knob that rotates) so that the recording level meters are set per the manufacturer’s
instructions (usually as high as possible without hitting the very top of the scale “0dB”)."

Of course, I didn't do any of that lol

[opsopcopolis]

That description from SP is absolutely terrible.  The word maximum should never be used in that context, at not without a qualifier of some sort

[lsd2525]

Low frequencies are almost always louder than high frequencies at a show (if not, you'd run screaming).  Thus, the low frequency will cause the clipping.  When a signal is clipped, very roughly speaking, it turns from sine to square.  A squarewave has lots and lots of high frequency that wasn't there in the unclipped signal.  So, you get relatively much more HF content.

Ahhh. Makes sense now. Thanks for the lesson.

I got to pay more attention next time