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Gear / Technical Help => Ask The Tapers => Topic started by: all_screwed_up on September 27, 2003, 07:21:34 AM

Title: How to decide for the correct bass roll-off settings?
Post by: all_screwed_up on September 27, 2003, 07:21:34 AM
Hi,

finally I managed to put together my new gear.  :)

I'm going to a rock show on Monday which takes places in an old warehouse (it holds around 1000 people) to test my new gear. But I was wondering which roll-off settings I should use? Do you have any idea when to pick which frequency?  ???

I'm using:
SP-CMC-8 > SP-SPSB-1 > Nomad Jukebox 3

Thanks a lot for your help.  ;)
Title: Re:How to decide for the correct bass roll-off settings?
Post by: dklein on September 27, 2003, 11:31:12 AM
Have you tested your setup yet?  Beware the input jack problem if you're using analog...
Title: Re:How to decide for the correct bass roll-off settings?
Post by: all_screwed_up on September 27, 2003, 01:46:59 PM
can you give us an idea what you have as options?

I can use 16, 69, 95, 107, 160, 195 or 888 Hz as roll-off frequency.

Quote
Have you tested your setup yet?  Beware the input jack problem if you're using analog...

Yes, but only at home, recording some music. The input jack problems don't occur at my JB3.   :)
Title: Re:How to decide for the correct bass roll-off settings?
Post by: Sean Gallemore on September 27, 2003, 03:40:19 PM
I use 95hz for all of my applications (rock, metal, even nickle creek ;) )
but some say that is too much...
Title: Re:How to decide for the correct bass roll-off settings?
Post by: F.O.Bean on September 27, 2003, 07:29:31 PM
if yer running yer source >comp program, id say NO ROLLOFF, if it needs it, you can do it POST-production... 8)wavelab has a couple NICE plug-ins for that....if the bass is POUNDING off of yer chest, i might use it, but every time i ALMOST did, im GLAD as hell i didnt...... ;)

my 00.02

bean
Title: Re:How to decide for the correct bass roll-off settings?
Post by: zhianosatch on September 27, 2003, 09:50:21 PM
capturing all that bass at theo show means you capture less of the good stuff...
Title: Re:How to decide for the correct bass roll-off settings?
Post by: zhianosatch on September 27, 2003, 10:47:22 PM
it really is necessary sometimes... often at the shows i tape!
Title: Re:How to decide for the correct bass roll-off settings?
Post by: nickgregory on September 28, 2003, 03:51:11 AM
it is necessary at any show that employs a bass cabinet actually.  I have my setup at 107Hz rolloff - this is the SP AT853 stealth setup - and the reason for the rolloff is because (1) the mics WILL distort at bassy shows - and keep in mind the reason for this, when alot of us are stealthing, the mics are on our head somewhere, and where is the bass cabinet usually.....head level, and (2) as Armen said, you get a wider range captured on the tape...vs. a boomy type recording.

Best way to figure it out is start somewhere and experiment...you will figure out to your tastes soon enough!

Nick
Title: Re:How to decide for the correct bass roll-off settings?
Post by: Sean Gallemore on September 28, 2003, 06:47:09 AM
it is necessary at any show that employs a bass cabinet actually.  I have my setup at 107Hz rolloff - this is the SP AT853 stealth setup - and the reason for the rolloff is because (1) the mics WILL distort at bassy shows - and keep in mind the reason for this, when alot of us are stealthing, the mics are on our head somewhere, and where is the bass cabinet usually.....head level, and (2) as Armen said, you get a wider range captured on the tape...vs. a boomy type recording.

Best way to figure it out is start somewhere and experiment...you will figure out to your tastes soon enough!

Nick

well said, I knew someone would be able to describe it better than I could.  I wanna hear the modded box armen!
Title: Re:How to decide for the correct bass roll-off settings?
Post by: zhianosatch on September 28, 2003, 01:46:33 PM
same here! custom filter, custom settings, custom addition leaving nothing more to be desired, top notch expertise and super quality workmanship, from what i hear...
should be totally worth the $200! and it's STILL less than a pair of "HEBs"... fuck that shit
Title: Re:How to decide for the correct bass roll-off settings?
Post by: Sean Gallemore on September 28, 2003, 05:52:05 PM
I want to hear what  binaural mics sound like in the first place, lol
Title: Re:How to decide for the correct bass roll-off settings?
Post by: zhianosatch on September 28, 2003, 06:01:40 PM
haha, wow, that could be too much for my brain
Title: Re:How to decide for the correct bass roll-off settings?
Post by: all_screwed_up on September 30, 2003, 09:07:44 AM
I taped without using bass roll-off yesterday and I got a quite good recording. :)

Thank you very much for your suggestions!
Title: Re:How to decide for the correct bass roll-off settings?
Post by: zhianosatch on September 30, 2003, 11:31:00 AM
cool, good times!
Title: Re:How to decide for the correct bass roll-off settings?
Post by: dklein on October 01, 2003, 01:24:00 PM
Also keep in mind that the real bass rolloff varies with the impedance of your input.  In most cases, if you go line in - the bass rolloff won't do anything!

If you go mic in - you have to know the impedance of the input to know what rolloff you're getting.  Any battery box that is labelled with frequency rolloff is making an assumption about the input impedance - if your recording device is the same, great.  If not, the numbers are wrong!

Example:  For the most (all?) of the Sony DATs, mic-in impedance is 4.7K, and 'line in' is 47K.  A box with a rolloff at 120Hz on mic-in will only be 12Hz on line in (non-existent).  
The same battery box plugged into a Sharp mini disc (10k mic-in, 20k line-in) will give you a rolloff of 56Hz on mic input and 28Hz on line-in.

Also - the rolloff is a slope, not a sharp cut so it's not that you get 0 below the cutoff - that's just where the slope begins.  The steepness of the slope can vary but most boxes will be down 6dB per octave.  That's -6dB each time you halve the frequency. So for the same example above on a Sony DAT using mic-in
120Hz - no effect
60Hz - down 6dB
30Hz - down 12dB

You can get a feel for how much that is by trying it with software on one of your recordings that wasn't rolled off.

If anyone wants a relatively easy way to do these conversion between devices just let me know and I'll post it.  I know I tend to get excessively technical sometimes.... :P
Title: Re:How to decide for the correct bass roll-off settings?
Post by: dklein on October 01, 2003, 01:51:34 PM
Here's the easiest way to convert.  You need to know the rolloff frequency and impedance assumed by your battery box maker for their calculations.  They will be able to tell you if it's not labelled or in your manual.

Actual rolloff freq. = stated rolloff freq * stated impedance / your impedance

frequency is in Hertz (Hz)
impedance is in Ohms - usually with a 'k' in front meaning thousands

So if they say 120Hz at 4.7k and you've got a 10k impedance on your recorder:
Actual = 120*4.7/10
           = 56 Hz
Title: Re:How to decide for the correct bass roll-off settings?
Post by: Sean Gallemore on October 02, 2003, 02:41:25 PM
this has me thinking, I have my BB@ 95htz, but I go line-in

i wonder if the bass roll-off is actually working
Title: Re:How to decide for the correct bass roll-off settings?
Post by: zhianosatch on October 02, 2003, 03:41:11 PM
yes, schwilly, it is, but not by much
dklein is right on, i've had detailed conversations about this very subject
so the bottom line is, sound pro is completely wrong in using those frequency settings
Title: Re:How to decide for the correct bass roll-off settings?
Post by: dklein on October 02, 2003, 04:19:41 PM
this has me thinking, I have my BB@ 95htz, but I go line-in

i wonder if the bass roll-off is actually working

Call/write sound profs to find out what impedance they used for the rolloff calculation and then look up the number in your manual.  I can help you from there...

If I had to guess, thru line-in on your Sharp md you'd be getting a rolloff anywhere from 1/4 to 1/2 the value published (like 25-50 Hz) and wouldn't likely hear much difference between the two.  Take it to a show you don't care about taping and record, switching back and forth taking note of the time you make the switch.
Title: Re:How to decide for the correct bass roll-off settings?
Post by: Sean Gallemore on October 03, 2003, 02:44:59 AM
this has me thinking, I have my BB@ 95htz, but I go line-in

i wonder if the bass roll-off is actually working

Call/write sound profs to find out what impedance they used for the rolloff calculation and then look up the number in your manual.  I can help you from there...

If I had to guess, thru line-in on your Sharp md you'd be getting a rolloff anywhere from 1/4 to 1/2 the value published (like 25-50 Hz) and wouldn't likely hear much difference between the two.  Take it to a show you don't care about taping and record, switching back and forth taking note of the time you make the switch.

thanx for the help!  I didn't think it doing much, which is ok because these mics aren't bassphiles anyway

I don't even make it to shows I want to go to!