how to keep bass/overload from ruining recording?

[mellzers]

Well, I found this site quite accidentally by google and I am hoping I can get some help for a problem I have. I did search and read the forum and picked up some lingo but a lot of the posts went way over my head. I know next to nothing about electronics.

I have a Sony MZ-N707 and binaural microphones (SP-BMC-3) from Sound Professionals. I use the automatic volume level for recording since I never know how loud the show will be or what the acoustics will be like where I am sitting (does this contribute to the problem?). I only "stealth record" (see, I told you I picked up some lingo!) live musical performances (like Phantom of the Opera, Les Miserables, etc) and although I'm fairly happy with the quality of my recordings, the clipping/overloading/bass can really irritate me. I've attached a clip from my latest escapade and you can hear how the bass pretty much shot the entire thing (bassyrent clip). Also, even if the bass doesn't kill the recording, I generally have this overloading - maybe it's referred to as "brick walling" or something else by you all, I'm confused. When someone hits a high note or is really loud there's this scratchiness to the sound (scratchyphantom clip).

Since my recordings mean a great deal to me, I would like to be able to prevent that. I've been browsing the gallery of live recordings and some of you have some AWESOME quality audios - I'd love to make it to that level. Would a battery box...thing...with bass roll-off fix this?

(Also, I am very impressed with the level of security some of you have had to face to "stealth record!" I've snuck in a camcorder over a dozen times to musicals and no one has batted an eye - I feel very lucky.)

bassyrent.mp3

scratchyphantom.mp3

[greenmachine]

Sample #1 is most probably preamp overload, which you can avoid by using a battery box and record via line-in (no roll-off necessary, no need to cut off anything, line-in can't easily be overloaded, particularly not by small diaphragm microphones without preamp). The recording might also benefit from a more thought-out mic placement, sounds close to mono. Separating the mics to approx. distance of your ears will usually help.

Not sure about sample #2, could be a different problem, maybe the levels were set too high.

Try to get used to manually setting the recording levels, usually yields much better results, AGC destroys dynamics by compressing the material. Also if you have to record via mic-in, make sure the input sensitivity is set to low (in the options menu).

[A440]

All of greenmachine's advice is excellent, although I don't think the MZ-N707 has a microphone sensitivity option--it's always High. Don't worry about it.

Let me offer a few specific recommendations on battery module (Microphone Madness) and recording level (18 to 20 out of 30, or about 2/3 of the way up).

If you're in the US, get this battery module:

http://www.microphonemadness.com/products/mmcbmminminc.htm

and connect mic--battery module--Line-in. Sound Professionals has similar ones, but this is small and about $10 cheaper than Sound Pros, or it was the last time I looked.

(If you're in Europe, get one of greenmachine's battery boxes!)

The battery module starts using its battery power when the mic is plugged into its jack. So leave the mic unplugged from the battery module as much as possible--don't store them connected. I don't know how long the batteries in the module last, but it's quite a long time--maybe 100 hours of recording.

Manual Volume will give you much better recordings, and it's worth using, although you have to re-set it each time you start recording--the unit always defaults back to AGC. Although it seems complicated the first few times, you'll get used to the sequence of clicks pretty fast. I tend to use 18 to 20/30 and it works well for most amplified concerts.

Here's how:

With a disc in the unit and the battery module plugged in to Line-in, hold PAUSE and press REC. Then Menu/REC SET/Rec Volume/Manual. Set the recording level at 18 to 20/30, 2/3 of the way up the bars. That should give you some room if it gets extra loud.

Leave the unit on Pause and HOLD with all its settings correct. When you want to record, push the PAUSE button again to un-pause and start recording.

----------------------------------------------

There's one other method, the attenuator (that's a picture of one in my avatar). You can get the Radio Shack Headphone Volume Control (US) or Maplin VC-1 (England), a volume control on a cord that lowers the signal going into mic-in. Mic--attenuator (at full maximum volume, not turned down at all)--Mic-in, also with manual volume at 20/30. If it gets really loud and you're watching your levels, you can use the volume knob on the attenuator to lower your recording volume--but you will hear the change on the recording, and you may get a little static from turning the knob.

The attenuator is the cheap and imprecise method of doing what the battery module does better. Its only advantage is that it gives you a record-level control that the MZ-N707 doesn't have while recording--though it's better not to change volume during recording. On the other hand, if the battery in the battery module runs out, as it will after months of recording, it's nice to have an attenuator in your pocket too.