Topic: Tips on SP-SPSB-1 bass rolloff.

[voodoostrat]

Greetings TS,

I started taping this spring. I was trying to do it on a low budget (still am really), I was trying to get by using my iPod touch with a Tascam iM2X. After 4 failed attempts I decided to get a Sony M10. I tried to get another show taped going without a preamp/battery box and without external mics. I taped a Los Lobos show out at Valley Springs Casino in August. As expected results were far from stellar. That room is just a glorified gymnasium, really boomy. So I found some CA-14s Omnis here in the Yard Sale and bought a SP-SPSB-1. I gave it another go about a week ago in Pomona again with the Los Lobos. They were playing on the horse racetrack facing the giant concrete grandstands.

Being a friend of the band I have no problem getting access to the SBD area to set up. On this night/venue the SBD area was extremely small and crowded. I decided to give it a shot from my seats about 7 rows behind and left of the board. I had never recorded a show with this rig (2nd show using the M10 in fact, but lotsa garage loud stereo time recordings), so I messed with the levels during the opener while trying to monitor thru headphones. The PA was really bass heavy so that had me worried. I rolled the Lobos show with knob set at about 4-1/2 which was giving me between -38db ~ -30db. The whole time I'm recording I thinking that I probably should have rolled off on some of the bass on the SP Batbox, the problem with that is I don't understand how to make heads or tails of the switches in the box, also it's a major PITA to get to them on the fly. Overall I'm pretty happy that I finally was able to capture a LL show with decent results. I'm gonna see them again next Friday out at Pappy & Harriet's and would love to pull a better recording. Any and all tips are greatly appreciated. Thanks to Zguy for the CAs, Daspyknows, F.O.Bean and my LL Hoodians - Crack, SJ, and Josephine for taking the time to help me get started in this madness.

Sorry I didn't link just a sample of the Pomona gig.

Gracias, Strat

http://bt.etree.org/details.php?id=566772

[adrianf74]

Okay, here's the manual for the battery box:

http://www.soundprofessionals.com/instructions/SP%20SPSB%201.doc

That should explain things clearly enough.  If you're getting -38dB to - 30dB with your M10 at 4.5, you might want to gain the input level up on the M10.  With a "flat" battery box (no roll off), I usually find I'm somewhere between 6 and 8 on the M10 (sometimes even higher).   I have to do this on a regular basis with my AT853's and battery box (I've even had to run MIC IN with plug-in-power OFF for shows that were too quiet.

As far as the dip switches (and "bass roll-off") go, there are two schools of thought on this:

1) Only roll bass off on your omnis.  Where to roll off is a matter of personal opinion; some people like 96Hz while others like 160Hz -- you'll have to play around with this a few times to figure out which you prefer.  This leads me to my preferred option...

2) "Fix It In Post."  That is, record the show with all the bass in the world and roll it off yourself using the Graphic EQ in a a post program like Audacity or Audition.  You can also add a slight bump around 1kHz if you feel the vocals are a little buried in the mix or do other little tweaks that will improve your final product.  This is by far my preferred method because you can always remove bass in a recording but it's hard to add it in after the fact.   

All of this is going to be trial and error for your first few shows (as you've experienced).   Another reason I don't like worrying about bass roll off is that there's a chance I could bring two pairs of mics (or two sets of caps) and switch it up because of my location.   If you ever run mini cardioid mics (should you get some down the road) you'll want to avoid bass roll off because they have a tendency to pick up considerably less bass.  Again, this can be fixed in post.

Hope this helps you out.

[voodoostrat]

Thank you kindly for the insightful tips, I appreciate it!

Strat

[earmonger]

Just piling on here but...really, don't roll off the bass.  The reason for bass roll-off, I am guessing, is for a generation of preamps behind the Mic-in jack that just couldn't handle big bass and overloaded when it arrived.  (The minidisc recorders I started with were notorious for this.)  Mic-in preamps have apparently improved. And if you run your battbox through Line-in there is no preamp to overload.

So just run it and record what may be a bass-heavy mix--what are those sound guys thinking?--as accurately as you can. Then use EQ to tweak it. You can't add the bass that you never recorded, which would give the music some oomph. But you can lessen what you've recorded as long as it didn't overload to begin with--which, through Line-in, is unlikely.

[nassau73]

I haven't had a chance to work on comparison recordings, but I was told that if I used a 120Hz rolloff rather than 30Hz (the 2 choices I have on my bbox), it would help diminish some of that concert hall "boominess".

What do you folks do for that?

[anr]

I'd use a paragraphic equaliser (Waves do one with a 46dB notch filter) and seek out and remove nasty resonances.   

[earmonger]

The lowest note on a piano is 27.5 hz. Every time you double the frequency, that's an octave.

27.5 x 2 =55
55 x 2 = 110

Two octaves gone if you use the 130 Hz setting, and more.  Of course it depends how steep the roll-off is--does it record some of the music below 130 Hz? a lot of the music below 130 Hz?--but if you go to a typical rock concert there are notes lower than 27.5 Hz from the bass, and if you go to a reggae or hardcore or EDM show those subwoofers are way below 27.5. 

Look at the chart here to see how much of a piano you would be cutting off if you go to 130 Hz.  It would be 27 notes out of an 88-note keyboard.

http://en.wikipedia.org/wiki/Piano_key_frequencies

Bass roll-off at 130 Hz  might be useful if you are trying to record someone talking or singing and there is a subway rumbling under you--then all the bass is noise.  But trying to cut out boominess by cutting out all of the low frequencies is very crude and will leave you with a tinny recording.  At a typical rock show the bass is not noise, it's depth and richness.

As I and others have suggested above, it's better to  record without rolloff and tweak later.

[anr]

My view is that it is roll-off, not cut.  Most of the music below the roll-off frequency is still recorded, but just at a lower level.  It is wrong to say it isn't recorded, so is lost forever.  It can be boosted in post, but with an increase in noise floor.  But, that would be largely inaudible, especially on recordings with persistent bass. 

That said, I set my SP battery box to the lowest setting (16Hz) due mainly to the type of music I usually record (acoustic).  I edit a friends recording for her and there is one venue she goes to where the bass bins are both huge and loud, and the recordings nearly always have distortion in the bass range.  I'd say that is an example of where a higher cut-off is required, and even then it only helps if it is the (stealth) recording rig that can't handle it. 

[darktrain]

My view is that it is roll-off, not cut.  Most of the music below the roll-off frequency is still recorded, but just at a lower level.  It is wrong to say it isn't recorded, so is lost forever.  It can be boosted in post, but with an increase in noise floor.  But, that would be largely inaudible, especially on recordings with persistent bass. 

That said, I set my SP battery box to the lowest setting (16Hz) due mainly to the type of music I usually record (acoustic).  I edit a friends recording for her and there is one venue she goes to where the bass bins are both huge and loud, and the recordings nearly always have distortion in the bass range.  I'd say that is an example of where a higher cut-off is required, and even then it only helps if it is the (stealth) recording rig that can't handle it.

Roll off has nothing to do with distortion, you can roll off all you want but it will still distort if it is to loud, That's the biggest misconception of the roll off feature. If the mics can handle the SPL then they can, if they can't they will distort roll off or not. Or else signal is too hot from the pre if using one. Rolling off in post is easy and I am no computer genius. In my case I simply use wave pad and the Hi Pass feature.

[voodoostrat]

Hi Y'all,

After Adrianf replied I thought this thread had died, that being said I went with his advice (no rolloff) and things have been just fine. The Pappy and Harriet's gig came out great minus the crowd being picked up by the omnis. I've since picked up a set of CA14 cards and gave them a go a couple of weeks ago and that one also came out great. My last show I had my M10 at nine and barely got to -30dbs-ish. I was at the board, maybe 100' back. The Lobos were going acoustic at this show, not crushingly loud, but still at a high volume. I want a preamp, to give me another option on my rig.

Thanks to all in this board for your insight, your deals in the YS, and for answering all my PMs.

[Gutbucket]

The lowest note on a piano is 27.5 hz. Every time you double the frequency, that's an octave.

[snip]
Look at the chart here to see how much of a piano you would be cutting off if you go to 130 Hz.  It would be 27 notes out of an 88-note keyboard.

http://en.wikipedia.org/wiki/Piano_key_frequencies

Yes, but it's mostly harmonics and octave strings we hear from those low piano notes rather than the fundamental itself.  The notes won't dissapear if you severely attenuate everything below say 60Hz, most bookshelf sized speakers will roll off about there anyway. The low bass is important, but primarily for feel, heft and spatial envelopment.

But if you go to a typical rock concert there are notes lower than 27.5 Hz from the bass, and if you go to a reggae or hardcore or EDM show those subwoofers are way below 27.5.

Eh, not that much lower.  Huge PA subs usually don't go super low, they are primarily designed to output outrageously high SPLs at normally low frequencies down to around 30Hz.  It's a huge excess of bass in the 30-120Hz range that is shaking your body and potentially overloading the mics.  Most of the excess boom will usually be somewhere between 60-120Hz.  There may still be super low information down there on the recording if you are using omnis though.

Bass roll-off at 130 Hz  might be useful if you are trying to record someone talking or singing and there is a subway rumbling under you--then all the bass is noise.  But trying to cut out boominess by cutting out all of the low frequencies is very crude and will leave you with a tinny recording.  At a typical rock show the bass is not noise, it's depth and richness.

As I and others have suggested above, it's better to  record without rolloff and tweak later.

Totally with you on all that.  I even feel roll-off or high-pass in post is usually too blunt a tool, prefering more precise, targeted EQ adjustment, even if it needs to be a significant if carefully targeted cut.

[anr]

Darktrain

I think we're saying the same thing, but referring to different parts of the signal chain.  As you say, a Battery Box cannot get rid of the basic distortion, but if the fundamental is down in the low bass range (my example), and is high in level, then I think I'd  use roll-off, reducing the risk of it being further distorted later in the signal chain.  Then, as I said earlier, look for nasty frequencies in post.



Gutbucket

Agree entirely.