Topic: Low Cut Question

[dave570]

Suppose someone was going to tape a loud show with the CA-14s and Edirol R-09HR and was sitting near one stack on the side, with no battery box or pre-amp.  Should that person keep the Low Cut on or off?

[taperwheeler]

That close and loud...you'll get distortion if those mics aren't getting good voltage.

[dave570]

So, would low cut help?    Usually this person turns it off.

[Church-Audio]

Suppose someone was going to tape a loud show with the CA-14s and Edirol R-09HR and was sitting near one stack on the side, with no battery box or pre-amp.  Should that person keep the Low Cut on or off?

Reducing bass after the mic does not reduce distortion this was a myth started by a very big company that sells stealth microphones.. Why because the distortion is happening inside the mic not after the mic. My mics should never be used with a bass roll off. You must use a battery box if you want to tape really loud shows.

Chris

[nameloc01]

The best roll-off is no roll-off.

[Church-Audio]

So, would low cut help?    Usually this person turns it off.

No it will not help I have heard of people using as high as 800 hz for a bass roll off... Of course that does not eliminate the distortion but because the filter is so high it filters out most of the frequency range that is overloading. As a side effect it also gives you that warm AM radio sound we all love and aspire to in our recordings


I dont mind using a bass roll off when your using an omni mic because low frequencies are omnidirectional
and if your mic is omni directional then you have a natural build up of bass frequencies adding a bass roll off can help. I really prefer to do that in post and not commit it to tape. There are times when a bass roll off is needed sometimes outdoors you need something to reduce the overloading of your recorder in that case a bass roll off could be used before the deck but again your sacrificing audio quality to "reduce" some of the wind noise.

Most wind noise is anywhere from 50hz to 150hz this can be done in post as well but it gets tricky when you have a huge wind gust that drives your mic preamp into clipping. Its always a fine balance between quality and what you must do to get the job done. Remember adding a high pass filter or bass roll off does not reduce the distortion that a mic produces it only masks it at the cost of lowing the fidelity of your recordings.



Chris

[stevetoney]

Another post that I'm very slow on (I'm wasting time today, so looking back on some week old posts).

It's implicit in the responses, but what possibly hasn't been explicitly stated here is that the only thing low cut typically does is acts as a filter for the bass frequecies, the same as an EQ filter does in the software used in post.   As you've pointed out Chris, some people seem to think that there's a different kind of magic that happens with the low cut function where there's a possibility that clipping can be eliminated.

[Roving Sign]

Another post that I'm very slow on (I'm wasting time today, so looking back on some week old posts).

It's implicit in the responses, but what possibly hasn't been explicitly stated here is that the only thing low cut typically does is acts as a filter for the bass frequecies, the same as an EQ filter does in the software used in post.   As you've pointed out Chris, some people seem to think that there's a different kind of magic that happens with the low cut function where there's a possibility that clipping can be eliminated.

Well - not magic - but if the peaks are being caused by some low, loud bass...Low cut might help reduce gain from those frequencies and reduce the likelihood of clipping...wouldn't it?

[morst]

Well - not magic - but if the peaks are being caused by some low, loud bass...Low cut might help reduce gain from those frequencies and reduce the likelihood of clipping...wouldn't it?

It depends on what's peaking. If the mics are brickwalling the input before the low cut, the horse has already left the barn, and it's no use closing the door. If you catch my drift.

[Church-Audio]

Another post that I'm very slow on (I'm wasting time today, so looking back on some week old posts).

It's implicit in the responses, but what possibly hasn't been explicitly stated here is that the only thing low cut typically does is acts as a filter for the bass frequencies, the same as an EQ filter does in the software used in post.   As you've pointed out Chris, some people seem to think that there's a different kind of magic that happens with the low cut function where there's a possibility that clipping can be eliminated.

Well - not magic - but if the peaks are being caused by some low, loud bass...Low cut might help reduce gain from those frequencies and reduce the likelihood of clipping...wouldn't it?

It will help nothing. Trust me if your sending to much signal into your recorder reduce the input level. It will do nothing at all for reduction of distortion. It will in extreme cases reduce your ability to hear it but its there and it never goes away. So if you are having distortion issues with your mics its time to get new mics and stop using a high pass filter to "cover up" what your mics are doing besides although the distortion is happening at a low frequency and your reducing it with a high pass filter your not reducing the harmonics above the xover point of the filter.

I am from the school that using a bass roll off on a cardioid is not a good idea simply because the low frequency response of most cardioid's is nowhere near as good as a good omni mic.

Many people have made lots of $$$ from ignorance and the proliferation that somehow a bass roll off eliminates distortion that is happening at the mic level is spinning fairy tales.

Now when you have an omnidirectional mic by all means use the bass roll off but understand the reason your using it is not to eliminate distortion but to reduce the omni directional bass bump that is caused by frequencies below 250hz approximately. This is because the lower in frequency you go the more "omni directional" your sound source becomes.. So when you combine an omnidirectional mic with a omnidirectional sound source you have a bump in the low frequency range. That is why when using omni mics it is critical that you point the mics at the source to maintain the HFC or High frequency content of the source thus balancing out the recording this directionality is not so much a product of the mic but more of the source. Most sources become more directional the higher the frequency becomes.

People assume that just because a mic is omni directional it magically picks up everything evenly even off axis and in a perfect world it would but when you can point the mic at the source and get closer to the source an increase in direct to reflected energy is also some what reduced making for a more balanced recording with less room and more signal. This is why we use boundaries like the jecklin disc to steer the mics directionality and to increase stereo separation so playback through speakers becomes more possible.


Sorry to go off on a tangent about omni mics but I thought that some of this information could be useful in understanding why we use a bass roll off and when we should use one.
Chris