Topic: Low end distortion

[PhxHorn]

I've only taped a few major rock acts, and my first try (Robert Plant last summer) turned out very well, even from the 3rd row.  I don't have a fancy rig, just a Zoom H2 with an SPSM-13 mic and an SPSB-8 battery pack, no bass roll-off.   I figured I could just use the bass cut on the Zoom. 

Anyway, the Plant show had a lot of bass hanging in the air up front, but it still turned out excellent, one of the better recordings of the 2010 tour.   Then I recorded Tom Petty at the end of the 2010 tour, and mistakenly had the battery pack plugged into the line input (duh), which sounded terrible, bass distortion everywhere.   Fortunately, some other folks taped the show and got a nice pull.    So I made a mental note to make sure I use the external mic inputs, which I did last night.  The artist was Joe Bonamassa.

But Joe last night was very very loud, actually too loud, with lots of bass.  Been a long time since I've seen an act that loud, maybe SRV back in the day.   I don't go to a lot of really loud shows.   My ticket was a spur of the moment purchase in the 5th row about 20 feet in front of the subwoofer stack.   I had the Zoom's mic input set at medium, and the volume still had the levels pinned, and so I switched to low very quickly.   That put the recording levels at a good level, but the kick drum and bass still have a fair amount of distortion on the recording.  He played a solo acoustic number and even some of the really loud low notes on the acoustic guitar are distorted.   I've EQed it out mostly and it's listenable through a stereo but not so good with headphones.   I may put it up at Dime, and maybe not.  But I'm wondering if anyone has any advice on how to handle such a situation with this type of equipment, hopefully without spending a fortune replacing everything.    I saw the 'arena rock' thread here, and I guess getting a more centered and farther-back seat would help, but this volume was pretty extreme and I think it would have been deafening even in the 10th or 15th row.   Is it necessary to get a battery pack with a bass rolloff?  If so, at what frequency?

This show wasn't all that important to me, because I was really just seeing him out of curiosity.  I never saw Gary Moore, and after his untimely death I thought I'd look up Joe B, and it turned out he was coming to town just a few days later, and so I bought the 5th row ticket that was open.    But I really don't want to screw up a recording that's important to me, and I'm sure some other folks out there would have appreciated a good pull on this one.   Thanks.

[acidjack]

Bass rolloff has no impact on the distortion you're hearing; it's a matter purely of the sound pressure levels in the room. It sounds like maybe your mics need the "4.7k mod" or "low sensitivity mod" as Sound Pros calls it. 

I'm surprised that you said running LINE-IN caused you a problem; normally running mics>BB>line-in is preferred.  Using the MIC inputs, you are more likely to get distortion.

Looking on Sound Pros page, it says: Maximum Input Sound Level: 105 dB SPL, 1 kHz at 1% T.H.D. (120dB when powered by our battery module)

120dB should be enough, although from what I understand those figures are not always terribly accurate, especially as regards low frequencies.

Because I know someone else will do it anyway, I would suggest that if you plan to do a lot of taping you might consider Church Audio CA-1 or CAFS-OMNI mics, which work with your existing batt box, are quite small and stealthy, and won't distort. And cost the same as what you have... Just a thought.

[hi and lo]

120dB should be enough, although from what I understand those figures are not always terribly accurate, especially as regards low frequencies.

Couldn't be more true; I trust the specs of very few manufacturers in this industry.

Check the voltage on the battery used in the bbox with a multimeter. Make sure it's 9+ and remember that leaving mics plugged into the bbox when not in use will continue to drain the 9v.

I don't know how 'hot' the spmc-13's are, but if you ran line in it's more likely the source of distortion is the mics themselves (generally referred to as "overdriven"). If the battery was drained, your max spl that the mics can handle will dramatically reduce. It's possible you overloaded the line input of the zoom (no idea what the maximum input rating is), but less likely than the mics being overdriven. If this is the case, you'd want an attenuator cable between the bbox and recorder's line input.

[PhxHorn]

Yeah, the more I've been thinking about it, I figured it was the sound pressure levels in the room.   I guess the 9V battery could be getting tired, it's got a few hours use on it, but I think they are supposed to be good for quite awhile.   I just put it to my tongue, and it doesn't exactly hurt, but there is still a moderate charge.    I'll swap it out anyway and look into the mics recommended above.   I know a single point stereo mic doesn't get the same separation as the separated ones, but I do like the fact that it is so innocuous-looking.   Does Church have something similar, or do I have to go with the separated ones?

[PhxHorn]

I guess I should have been clearer, I used the external mic input last night.  I'd used the line input with Tom Petty, which wasn't that loud, and that was the first time I ended up with heavy distortion.    I thought using the external mic input would solve the problem, and while the distortion was much less with the show being much much louder, it was still there. 

[hi and lo]

The mic input will overload easily and if you didn't not run line in, I'll bet the farm that's the cause of your distortion.

A 9v will typically last 100s of hours in a standard bbox... if the mics are disconnected between use.

lol at the tongue test.

[PhxHorn]

The line input distorted with Tom Petty's moderate volume level, and the mic input distorted at a high volume level.   However, I recorded the Count Basie band just a couple of weeks ago from the front row, and it was pretty damn loud acoustically, and there was no problem at all with the mic input.    Is one of the inputs better for higher volume levels?

[Belexes]

Church Audio makes very tiny omni mics with the CAFS and CA-1's.  Pretty easy to do discreet taping.  I don't think you'll find many here that have used the SP mic you have.

[Teen Age Riot]

The line input distorted with Tom Petty's moderate volume level, and the mic input distorted at a high volume level.   However, I recorded the Count Basie band just a couple of weeks ago from the front row, and it was pretty damn loud acoustically, and there was no problem at all with the mic input.    Is one of the inputs better for higher volume levels?

As you had distortion problems using both the line and mic inputs, it's very likely that the mics are to blame.

[kfrinkle]

I spent sooo much time trying to get my SP mics to not distort at high SPL shows.  Strange thing, was I think it had more to do with my recorder than anything else.  People would have the same CMC-8 mics as me, going line-in to a DAT and get great results, while me going line-in on my MicroTrack would get nothing but shit.  I changed over to the Church Audio mics, and got a Sony PCM-M10 and now I do not worry about distortion.

Moral of the story:  Get rid of the SP mics.  They are nothing but trouble at loud, bass heavy shows.

[acidjack]

Yeah, the more I've been thinking about it, I figured it was the sound pressure levels in the room.   I guess the 9V battery could be getting tired, it's got a few hours use on it, but I think they are supposed to be good for quite awhile.   I just put it to my tongue, and it doesn't exactly hurt, but there is still a moderate charge.    I'll swap it out anyway and look into the mics recommended above.   I know a single point stereo mic doesn't get the same separation as the separated ones, but I do like the fact that it is so innocuous-looking.   Does Church have something similar, or do I have to go with the separated ones?

I think you'd be better off (MUCH) better off, in terms of quality of recordings, to go with 2 separated tiny mics.  They will be no more conspicuous than what you have now.  I don't know if Church has a single point mic like you have (I think he may) but even if he does, I'd still suggest the CAFS or CA-1.

The others are right, it's not your battery or your recorder's inputs; it's almost definitely your mic.  It's just not really designed for what you are doing with it.

I would not say this applies to all SP products, but if you record loud music, you need to be sure your SP product has a "low sensitivity" option and that you get it.  Church products are a bit more foolproof in this regard since all of his mics are designed for lower sensitivity to high SPLs.

[PhxHorn]

Thanks everyone, I'll look into the Church ones in the very near future!