Is there an Argument AGAINST High Pass Filters?

[The Ryantist]

Would a HPF benefit me if I always just play with headphones and/or SansAmp DI? Would the FOH mixer just add a HPF if he wants one? (the church where I play has a pro system and engineers who know what they're doing)

 

[Downunderwonder]

Would a HPF benefit me if I always just play with headphones and/or SansAmp DI? Would the FOH mixer just add a HPF if he wants one? (the church where I play has a pro system and engineers who know what they're doing)

maybe. It might clean up your headphone sound. Might save the day if regular engineer leaves his nephew in charge.

 

[zac2944]

I believe it to be the exact the opposite, Zac: you cut subsonic frequencies, or some very low-freq notes that your ear+brain interprets anyhow due to missing fundamental, therefore you reduce excursion. Higher notes require far less cone excursion, and you're not wasting a significant amount of wattage trying to reproduce sounds we can't quite hear anyhow.

I get what you're saying, and when HPF is applied correctly I think this would be the case. The scenario I'm picturing is one where the HPF is set too high or the slope it soo flat so that it is reducing output in the bottom of the audible range; say maybe 50-100Hz. This might cause a perceived loss of "booty" or fullness, causing the user to turn up in order to compensate. If this happens it might be possible to have excursion issues at the "hump" that occurs before the tuning frequency. Maybe?

 

[Szyszaczek]

From what I understand the orange would be without the HPF, and the blue would be with HPF.

As we can see adding HPF will reduce cone excursion in lower frequencies to prevent damaging the driver - most cases speaker cant reproduce the sound in sub-bass region.

But how it afects this hump above tunning frequency? The only reasonable explenation that makes sense to me is this:

I get what you're saying, and when HPF is applied correctly I think this would be the case. The scenario I'm picturing is one where the HPF is set too high or the slope it soo flat so that it is reducing output in the bottom of the audible range; say maybe 50-100Hz. This might cause a perceived loss of "booty" or fullness, causing the user to turn up in order to compensate. If this happens it might be possible to have excursion issues at the "hump" that occurs before the tuning frequency. Maybe?

 

[FerK]

Hey szyszaczek, I'm afraid that only in principle is your graph correct: in your example the cutoff frequency is set WAY too low, at 13.7 Hz (as per Active High Pass Filter A good bass HPF would be set at around 40Hz, or higher (I set mine around 50Hz). That means that the excursion reduction would be significant across a larger range of frequencies, and not only SO low, below the range of fundamentals produced by a 5-string bass (a 5-string's low B is around 31Hz) or even a 6-string (I guess that a 6-string's low F would be around 22Hz or so).

 

[XLunacy]

Alex Claber, Barefaced :

I was going to say don't use it but I've looked more carefully at the micro-thumpinator and it'll be fine and actually slightly beneficial. I'm generally not keen on customers using high-pass filters with our Gen 3 cabs because often they're set at too high a frequency which loses you useful LF output and decreases thermal power handling (by overly reducing cone excursion - and cone excursion is a key factor in cooling the voice coils in our drivers by pumping hot air out of the motor and sucking cool air in).

It depends on the filter slope and knee but around 30Hz is good. Up towards 40Hz is ok for SM/SC/ST but not for BB2/BT2/Two10/Six10. 50Hz is definitely too high for all of them.

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