Topic: Quick Bass Rolloff question...

[justink]

i did a search but didn't find anything to help me off hand.

it's been a while since i dusted off the gear...  what's a good bass rolloff setting for a solo instore performance?  more Hz means more roll off correct?

i had it set at 160Hz for OAR and Howie Day the last time i ran this gear, but there was a TON of bass on the tape.  i'd like to avoid that.

so, the higher i have the Hz set at, the less bass on the tape?

 i'm planning on rocking the [sp omni's -> battbox (195Hz) -> d7] for Robert Earl Keen tonight, instore performance, that is if they let me in w/ gear.

thanks!

-j

[Tim]

so, the higher i have the Hz set at, the less bass on the tape?

yes

[goose]

I'm not positive, but I don't think the rolloff will be effective going line in, only mic in.  If you ran line in previously, you may have nullified the rolloff setting. 

I'm sure someone can confirm or correct my thoughts.

[justink]

I'm not positive, but I don't think the rolloff will be effective going line in, only mic in.  If you ran line in previously, you may have nullified the rolloff setting. 

I'm sure someone can confirm or correct my thoughts.

i've always gone line in on the d7 even w/ the mc012 ->mixpad ->d7

how would line in nullify the rolloff?  i always thought line in meant a direct line from the batbox, the only thing the d7 did was convert A/D and record?

[fandelive]

I'm not positive, but I don't think the rolloff will be effective going line in, only mic in.  If you ran line in previously, you may have nullified the rolloff setting. 

I'm sure someone can confirm or correct my thoughts.

the roll-off is effective going line-in, but the only usefull preset in this case is the 888Hz. (at least for "boomy" rooms)
I'd recommend you to check out this thread for more information :
http://www.taperssection.com/index.php?topic=5534.0

[jeromejello]

those of us using a jb3, the impendance is 37kOhm.

the break out becomes:
16Hz > 4.3Hz
69Hz > 18.7Hz
95Hz > 25.7Hz
107Hz > 28.9Hz
160Hz > 43.2Hz
195Hz > 52.7Hz
888Hz > 240Hz

the last couple of shows i taped with the 69Hz setting (actually 18.7)  i think its ok, but not as effective as it could have been in the tabernacle.  i think i am going to set it to 95Hz (25.7) or even 107HZ (28.9) for tonights gig.

the way i look at it is this... while not as effective as i first was lead to believe, the roll off (while i am still using this battery box - until you sell me your oade mod ua-5) should allow me to cut the low, low end, allowing a higher gain on the recording without clipping.  i know nothing though.

[justink]

would that be the same for the d7 also? 

so, since i'm running omni's i should keep it on 888Hz or the next one down?

[Weazel]

d7 line in impedance is 47 kohm

[cgrooves]

Mic-in frequencies (based on the pcm-m1 Mic-In resistance of 4.7 kOhm) :
  (16Hz) >  32Hz    2,3,4   
  (69Hz) > 138Hz   1,4   
  (95Hz) > 190Hz   1,3   
(107Hz) > 214Hz   1,3,4   
(160Hz) > 320Hz   1,2   
(195Hz) > 390Hz   1,2,4   
(888Hz) > 1776Hz 1,2,3   

Line-in frequencies (based on the pcm-m1 Line-In resistance of 47 kOhm) :
(16Hz) > 3.2Hz    2,3,4   
(69Hz) > 13.8Hz  1,4   
(95Hz) > 19Hz  1,3   
(107Hz) > 21.4Hz  1,3,4   
(160Hz) > 32Hz  1,2   
(195Hz) > 39Hz  1,2,4   
(888Hz) > 177.6Hz  1,2,3

Also valid for the d7 (or any other unit with a line-in resistance of 47 kOhm)

[inside source]

Ok, so when I see that the recording was made using:
"SP-CMC-8 > SP-SPSB-6 (rolloff @ 107 Hz) > PCM-M1 (line-in)"
does it mean that the bass rolloff was in fact not effective?! Considering that 107Hz/4.7=22.8Hz and frequency response for CMC-8 starts at 30Hz. And I might add that I see rolloff setting @107Hz into line-in quite often...

[cgrooves]

You've got it.  My chart is based off of a 10 kOhm resistance designed battery box translated to a 50 kOhm resistance line-in recorder. The m1's line in resistance is 47 kOhm, so the figures shown above are a little off. 

If you use the 195Hz setting, the roll-off is actually 41.5Hz Line-In on the m1. (Probably not enough roll-off for many situations)
If you use the 888Hz setting, the roll-off is actually 188.9Hz Line-In on the m1. (Too much roll-off for practically any situation)

Best thing to do with these mics is to go phantom, IMO, especially if using a Sony dat recorder. Phantom power will let you use these mics to their fullest range of SPL's.  Another option would be to alter your battery box so that the settings will be more useful to your recorder. You would think that they would offer this as an option on their battery boxes, rather than just building them based on a generic line-in resistance of 10 kOhm.

[inside source]

Thanks!

I compiled a quick table to see what are actual bass rolloff settings for various recorders.
Looks like this original bass rolloff option in SP battery box is in fact not useful for JB3 and DAT line-in, though people often use certain rolloff setting thinking it makes an effect, when actually it doesn't. For minidisc recorders it looks ok if the settings are doubled (see 160 Hz and 195 Hz option). I assumed that MD has 20 kOhm line input impedance, please correct me if I'm wrong. Is it correct for the new Hi-MD recorders? I didn't find it in the manual.

I borrowed the jumper settings from cgrooves post.

Table. Bass rolloff settings for line-in.
The values are rounded to the nearest number.

batt. box setting       MD          JB3         DAT
(based on 10kOhm)    (20 kOhm)   (37 kOhm)   (47 kOhm)

  16 Hz  -  2,3,4       8 Hz        4 Hz        3 Hz
  69 Hz  -  1,4        35 Hz       19 Hz       15 Hz   
  95 Hz  -  1,3        48 Hz       26 Hz       20 Hz
 107 Hz  -  1,3,4      54 Hz       29 Hz       23 Hz
 160 Hz  -  1,2        80 Hz       43 Hz       34 Hz
 195 Hz  -  1,2,4      98 Hz       53 Hz       42 Hz
 888 Hz  -  1,2,3     444 Hz      240 Hz      189 Hz

[dklein]

hey - nice chart.  Just for a reality check it might be worth checking the cap values that are being actually used (if you can see/read them)

[inside source]

Why my ticket was withdrawn?
Is this table wrong, or did I post something wrong in the other thread?
Just wondering about this ticket system which I don't understand yet..

[F.O.Bean]

its silly, they go up and down constantly, dont worry about the tickets

more info on them can be found in the archive section of ts.com