Setting Lo and Hi Cut Filters

[UMT]

Working with 2 31 channel EQ's... Where would you recommend setting the Lo and Hi cut filters?

 

Thanks!

[agedhorse]

What are you trying to do with them? What speakers and amps are you using? What other processing are you using? Details are needed.

[banddad]

It depends...

 

What are you using them for?

What cabinets are you driving?

 

For example, my settings for 12" stage monitors are about 90 hz and 12 khz, FOH speakers with subs are pretty much full range, using the HPF of the amp only.

[UMT]

 

What are you trying to do with them? What speakers and amps are you using? What other processing are you using? Details are needed.

 

 

Sorry. Running sound (which I don't normally do) to help out some buddies.

 

This is for FOH. Smaller gig to maybe 100 - 150 people. Using 2 large Sonic's (15" speaker with Horns) mounted on pole stands. Not sure what brand the amp is but it is around 400 watts and has no pass of any sort. No processing other than EQ... The Eq Lo Pass is currently set at 75 and the Hi pass at 10 and seems to work fine. I just wondered if I'm missing something.

[agedhorse]

Yes, you are missing something, those can't possibly be the settings on the filters.

 

Try the high pass filter at 50Hz and the low pass filter out (or 20kHz)

[RoadRanger]

What brand and model EQ's?

[UMT]

 

Yes, you are missing something, those can't possibly be the settings on the filters. Try the high pass filter at 50Hz and the low pass filter out (or 20kHz)

 

 

Ooops... Sorry folks! The knobs are labeled Hi and Lo CUT.. The Hi 'cut' has a range of 2.5 to 30 kHz and the Lo 'cut' has a range of 10 to 400 Hz....

 

This is a Behringer 3102 and I haven't used it before...

[RoadRanger]

Unless your audience consists entirely of old deaf guitarists turn the high cut up to 20khz .

[agedhorse]

Low cut at 50Hz, high cut at 20kHz is a good start

[dboomer]

Low cut at the sub box cutoff frequency at between 12-24 dB/oct.

 

High cut ... probably anything above 12 kHz but not at all might be just as good of an answer.

[agedhorse]

Box's -10dB point is around 40-50Hz, -3dB point is at least 50Hz.

[UMT]

 

Low cut at 50Hz, high cut at 20kHz is a good start

 

 

Just set it up and that works!

 

Thank you to all for your help...

[agedhorse]

No problem.

[Dogoth]

Sort of OT

 

I've never understood the utility of having a variable Lo pass filter built into a graphic. Either the speaker will reproduce it or not, but It's not like you're saving any power or wear & tear on the drivers. I can understand RF filters (but that's way above the audible bandwidth).

 

What's with that, and why are they there?

 

If one's present I bypass it if possible or take it to it's highest freq (bypassing is better because why add unneeded phase problems).

[Bugzie]

My understanding was that just because a driver can't physically produce a frequency, doesn't mean it won't try. As a result it will increase resistance and that causes heat.

Andy, old sage one, (LOL) enlighten us!

I run MRX 528 subs and there isn't much below 50 hz. When I run my amp QSC PL236 I use the 50hz cutoff and it seems to work well. Why waste wattage?

But I've been wrong before!

Andy, where would you reccommed setting the cutoff on the MRX 528?

[monkeyland]

 

Sort of OT I've never understood the utility of having a variable Lo pass filter built into a graphic. Either the speaker will reproduce it or not, but It's not like you're saving any power or wear & tear on the drivers. I can understand RF filters (but that's way above the audible bandwidth). What's with that, and why are they there? If one's present I bypass it if possible or take it to it's highest freq (bypassing is better because why add unneeded phase problems).

 

 

it absolutely saves power and wear and tear. the amp can focus on producing only the frequencies that you want and the speaker is not being asked to reproduce anything that it can't. the speaker will try to put out what is put into it even if it can't, it just gets converted to heat. this is why we use crossovers instead of just sending everything to our system full range.

 

i personally hi-pass my monitors pretty high. on a loud rock stage i'm mostly looking to add inteligibility to the vocals and all of that extra low end just seems to get in the way.

[agedhorse]

A low pass can help to get rid of cymbol wash and bleed through the vocal mics when used for monitors, and when used in commercial applications can improve the system residual noise under some conditions, for front fills can eliminate cymbol and other excessive HF material that may be washing off the stage anyway, etc.

 

Doesn't have anything to do with amps and speakers working harder, heat, wear & tear, or anything like that. You are talking about rolling off the very high frequency stuff, that's maybe a few watts at most.

[monkeyland]

 

Doesn't have anything to do with amps and speakers working harder, heat, wear & tear, or anything like that. You are talking about rolling off the very high frequency stuff, that's maybe a few watts at most.

 

 

if that was directed at my post i was mostly referring to hi-pass. i don't want any more low frequency content than i absolutely need in my monitors

[agedhorse]

 

if that was directed at my post i was mostly referring to hi-pass. i don't want any more low frequency content than i absolutely need in my monitors

 

 

You have high pass and low pass confused in your post.

[RoadRanger]

You have high pass and low pass confused in your post.

I hate when that happens .

[monkeyland]

 

You have high pass and low pass confused in your post.

 

 

not trying to argue but i wrote high pass because thats what i meant. i set the high pass on my monitor EQ to somewhere between 50 and 100hz depending on what the content of the monitor is going to be. i feel that i can get the speaker to sound out much clearer and louder if i'm not asking it to put out sound that i don't really need anyway.

 

you mentioned low pass to keep out cymbal wash which is something that i also do especially in rooms with low ceilings

 

 

i do see that someone a few posts before me what talking about the reasoning for low pass filters on EQs and hence some possible confusion

[agedhorse]

it absolutely saves power and wear and tear. the amp can focus on producing only the frequencies that you want and the speaker is not being asked to reproduce anything that it can't. the speaker will try to put out what is put into it even if it can't, it just gets converted to heat. this is why we use crossovers instead of just sending everything to our system full range.

 

[monkeyland]

understood. i see the confusion. it all made sense in my head.

 

and to be a little more on topic. i don't think i will buy another EQ that does not have variable high and low pass built in. i have a couple of the peavey ones with the variable filters and FLS and i love them

[Dogoth]

 

A low pass can help to get rid of cymbol wash and bleed through the vocal mics when used for monitors, and when used in commercial applications can improve the system residual noise under some conditions, for front fills can eliminate cymbol and other excessive HF material that may be washing off the stage anyway, etc.

 

 

That makes some sense to me. I still would probably rarely use it (why not just Hi pass the mics prone to the bleed, rather than the whole mix?). I can see the use in commercial applications (like ceiling speakers in a mirrored room kind of thing (or even fixing low ceiling HF beeming problems)).

 

Thanks

 

To the OP. You got it right. just keep doing what you're doing

[dboomer]

The original post spoke of HP/LP filters on a GEQ. So it's pretty safe to assume that the filters are being set to aid the amps and speakers.

 

As to why not HP the mics likely to bleed ... the answer is yes. The first place to start is to set the mic to the low and high frequency limits of the source that the mic is expected to pickup. But these filters will likely be in the channel strip.