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Gear / Technical Help => Ask The Tapers => Topic started by: guitard on July 07, 2006, 11:54:33 AM

Title: Bass roll-off switch
Post by: guitard on July 07, 2006, 11:54:33 AM
I'm still very new at this - so please excuse the question if it sounds really stupid.

I recently bought some Core Sound Cardioids.  They came with a battery box.  Someone asked me if I got the battery box with the bass roll-off switch - and I said no - there is no switch - just a rectangular box with a plug on one end.

I went back to the Core Sound website to try and find out more info about this option.  In the Cardioids section, I never saw any mention of bass roll-off.  Is this not an option with this style mic?
Title: Re: Bass roll-off switch
Post by: guitard on July 07, 2006, 12:22:03 PM
Moke ~ thanks for the response.

Here are the specs for these mics (as stated at Core Sound's website):

 The Core Sound Stealthy Cardioid microphones have a frequency response of from 40 Hz to 18 kiloHertz. They have a slightly rising frequency response over that range with the exception of a slight (2 dB) peak between 9 kHz and 12 kiloHertz and a bass response fall off of roughly 6 dB per octave starting at 100 Hertz. (The bass response is very similar to our Core Sound Binaural microphones' with the bass roll-off filter).

We match the microphone pair to within one dB of each other. One of our modifications alters the microphone's sensitivity to approximately -70 dB (0 dB = 1 Volt per microbar), making them ideally suited for recording extremely loud sound sources without danger of overloading your mic pre-amp. This very low sensitivity makes these mics less suitable for recording quiet sound sources. The microphones have a cardioid pickup pattern, rejecting sounds that are 90 degrees off-axis by at least 6 dB and at 180 degrees by at least 20 dB (measured at 1 kHz).

Thanks to our modifications, the microphones have an undistorted dynamic range of over 90 dB, compared to the unmodified capsules' approximately 60 dB dynamic range. They will handle sound pressure levels of more than 138 dB. They are designed to operate into a nominal impedance of between 4.7 and 10 KiloOhms. (If you need other impedances, please contact us.) Their self-noise level is approximately 35 dBA. This is far below the ambient noise level at concerts. (Note that the self-noise specification also makes these mics not especially suitable for recording very quiet sound sources.)

The Core Sound Stealthy Cardioid microphones require a bias voltage that is supplied by its accompanying battery box, the same that is supplied with Core Sound Binaural "battery box" microphones. Powered by a standard 9 Volt alkaline transistor radio battery, the box also contains associated electronics (top quality metallized polypropylene capacitors hand matched to 1%, and 1% metal film resistors) and a high reliability, US-made locking multi-pin connector. The battery box itself is roughly half the size of a cigarette pack, is made of sturdy die cast aluminum, and is finished in a durable black crinkle finish. The battery lasts approximately 500 hours and should be replaced at least once a year. The output to the recorder is a mini stereo phone plug; other connectors can be supplied upon request.
Title: Re: Bass roll-off switch
Post by: Gawain on July 07, 2006, 12:45:38 PM
related to this: can you change the roll off on the fly, while you are recording? (on an SP-spsb1)

and another thing about the same box: if I set on 'off' all the roll off little 'switches', I get no signal at all, is this normal? must I use always one of the roll off positions to make the box works?

Sorry for jump into this thread, I just thought it was a good one for this  :)
Title: Re: Bass roll-off switch
Post by: Chill on July 10, 2006, 10:49:58 PM
Do I need bass rool off with SP-CMC-2 (at831).  I dont have a box with bass roll off, I have been thinking of getting one. 

Thanks
Title: Re: Bass roll-off switch
Post by: gngrbrdman13 on July 11, 2006, 04:25:14 AM
How does one roll off the bass in post production using wavelab?
Title: Re: Bass roll-off switch
Post by: beathydrolysis on August 02, 2006, 02:24:00 AM
Do I need bass rool off with SP-CMC-2 (at831).  I dont have a box with bass roll off, I have been thinking of getting one. 

Thanks

I run have bass roll-off on my preamp that I use with my sound professionals cardiods and I wouldn't imagine doing a show without this particular feature.  To my ears bass roll-off really helps to strip the "mud" off the bottom end of my recording...but that's just my opinion.
Title: Re: Bass roll-off switch
Post by: woodcore on August 14, 2006, 07:24:54 PM
I'm still very new at this - so please excuse the question if it sounds really stupid.

I recently bought some Core Sound Cardioids.  They came with a battery box.  Someone asked me if I got the battery box with the bass roll-off switch - and I said no - there is no switch - just a rectangular box with a plug on one end.

I went back to the Core Sound website to try and find out more info about this option.  In the Cardioids section, I never saw any mention of bass roll-off.  Is this not an option with this style mic?

This is not an option with the CoreSound cardoids, and if it where you would not want to use it. The CS cardoids IMHO almost have too much rolloff already. The bass roll off switch is an option with the CS binaural set (omni's) and does come in quite handy!!!     
Title: Re: Bass roll-off switch
Post by: taper420 on August 14, 2006, 10:23:01 PM
I use shotguns that are 50hz-20khz so I don't ever really need to use the rolloff, even though it has one. What I'm wondering is, wouldn't it make sense to never use it. I mean if you can always just rolloff the bottom end on a software program, why bother doing it on the mics, which you can never go back on? Does rolling off on the mic or preamp at the live show have some hidden benefit I'm unaware of, that is different than post-eq work? I just say leave your options open.
Title: Re: Bass roll-off switch
Post by: beathydrolysis on August 15, 2006, 12:12:31 AM
You're spot on saying that there is nothing you could do with a bass roll-off that you couldn't do with post production.  However, having recorded many shows via mini disc (though I know you have a M100 that you use too taper420) I can say it is nice to cut some of the intensity due to the bass before you feed it into your player.  That way you can record the mid and treb part of the signal at a higher level on your unit.  Plus a lot of the lower end mics (price wise) don't have the best response on the bass end and a bass-roll off can help to keep you away from distortion and clipping.  Please let me know if I'm all wet.  That's just the way I see it.
Title: Re: Bass roll-off switch
Post by: taper420 on August 15, 2006, 05:11:57 PM
Makes perfect sence.....with 16 bit recording it's best to record as high a signal as posssible without clipping, and that's what the bass-rolloff allows you to do. With 24 bit recorders that becomes less of a concern, due to the higer dynamic range it's possible to boost levels in post without dramaticaly increasing the noise floor. I would comment though that legacy md recorders (not the new HiMD units), though they record to ATRAC which is a lossy format, have a 20 bit dynamic range.