ProSoundWeb Community
Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Alex Rigodanzo on July 03, 2014, 10:13:50 PM
-
I have a 40hz hpf on the subs xover. I also use the 30hz filter on the amps for extra protection. Good or bad idea? Or 6 of one, 1/2 dozen of the other?
-
The crossover wins at 40hz. No need to bother with the amp LPF, which may cause problems in the end (doubtful).
-
Filters do not have sharp right angle roll-offs, but affect well above the pole corner frequency. Stacking multiple nearby filters will cause more attenuation than expected.
If there is a crossover involved the extra filter can impact the integrity of the crossover dividing network, due to extra phase shift added to just the amp channel.
JR
[edit but do not lose too much sleep about this down in the dirt 30Hz. /edit]
-
[edit but do not lose too much sleep about this down in the dirt 30Hz. /edit]
I hear people talk all the time about how it is not important to have flat response down to 30Hz-and that is just for "weird electronic type music and rap"
Well go tell that to the local country or jazz band that has a bass player with a 5 string bass.
The low B is 31Hz. So I guess he would not mind if you just took that string off-since those notes are not important-----------------
I bet if he plays that note-there is a reason-and he probably wants you to hear it.
If the system can't reproduce it-then it is not being a good reproducer.
-
I hear people talk all the time about how it is not important to have flat response down to 30Hz-and that is just for "weird electronic type music and rap"
Well go tell that to the local country or jazz band that has a bass player with a 5 string bass.
The low B is 31Hz. So I guess he would not mind if you just took that string off-since those notes are not important-----------------
I bet if he plays that note-there is a reason-and he probably wants you to hear it.
If the system can't reproduce it-then it is not being a good reproducer.
Not so sure about that! You know some of the most popular bass amps can't reproduce anywhere near 30 Hz. It's not the fundamental tones that make up the sound of the instrument.
-
Sorry Ivan, I am not dismissing the bottom octave, that you do so well. The fact that the OP is dumping at 40 Hz and 30 Hz suggests he has made a cognizant decision to not get heroic about low bass. Filters at 30 Hz and 40 Hz will interact an cause more attenuation above and at their tuning.
Argue among yourselves over how much musical energy the typical playback system will reproduce down there. A little extra LF roll-off may be better for the OP if his system is marginal for amp head room. So I repeat he shouldn't lose sleep over it. Let Ivan worry for us all. 8)
JR
-
I hear people talk all the time about how it is not important to have flat response down to 30Hz-and that is just for "weird electronic type music and rap"
Well go tell that to the local country or jazz band that has a bass player with a 5 string bass.
The low B is 31Hz. So I guess he would not mind if you just took that string off-since those notes are not important-----------------
I bet if he plays that note-there is a reason-and he probably wants you to hear it.
If the system can't reproduce it-then it is not being a good reproducer.
You can take the low B string off because the bass player's rig can't reproduce the fundamental, either. And the harmonic content, which makes up much of our perception of bass guitar tone, begins an octave above the fundamental.
Bassist with more than 4 strings are just jealous of their higher-pitched bothers & sisters. /nudge, wink, satire
-
You can take the low B string off because the bass player's rig can't reproduce the fundamental, either. And the harmonic content, which makes up much of our perception of bass guitar tone, begins an octave above the fundamental.
Bassist with more than 4 strings are just jealous of their higher-pitched bothers & sisters. /nudge, wink, satire
But when you hear a system that CAN easily reproduce 30Hz (and below) it brings a whole new dimension and feeling to the music.
I feel the reason many people "dismiss" low freq reproduction is because they have not had the experience of a system that can do it.
I know-I used to be in that camp-but my mind has changed-once being exposed to it.
You simply hear so much more and get a different feeling from the music.
Of course it also has a bad side. We have had producers of certain songs we have used come up to us and say they have heard their "errors" because the system they mastered on could not reproduce those freq.
-
Of course it also has a bad side. We have had producers of certain songs we have used come up to us and say they have heard their "errors" because the system they mastered on could not reproduce those freq.
Not to mention unintended thumps and LF noise not supposed to be in the PA.
More is always better unless it isn't, YMMV.
JR
-
But when you hear a system that CAN easily reproduce 30Hz (and below) it brings a whole new dimension and feeling to the music.
I feel the reason many people "dismiss" low freq reproduction is because they have not had the experience of a system that can do it.
I know-I used to be in that camp-but my mind has changed-once being exposed to it.
You simply hear so much more and get a different feeling from the music.
Of course it also has a bad side. We have had producers of certain songs we have used come up to us and say they have heard their "errors" because the system they mastered on could not reproduce those freq.
Ivan, you know me personally and what I think of LF.... did you miss the "nudge, wink"?
Seriously, there is LF content in live sounds (musical and otherwise) that isn't reproduced accurately. I can live with that from both a personal standpoint and a business viewpoint. That "next half octave down" isn't a unicorn but it is very expensive to do well and most of _our_ clients aren't willing to pay an extra 3dB$ for an extra half octave.
As for the OPs question - stacking HPF filters will have audible consequences. It's up to you to decide if you like the way it sounds and IF it's really giving you extra protection or if you really need any extra protection this *might* provide. Alex, if I understand correctly you're the mixerperson running the console and you're also the 'system guy.' If you really need to stack HPFs I suggest that you need to exercise additional tonal control at the input strips or that you have other issues (Not Enough Rig for the GigŪ would be chief among them).
-
The reason was simply that we're using 4715's with 1800w per cab and I don't trust they can handle that low (so yes, technically not enough rig). They're rated -10db at 40hz. I may have been wrong, but it's a moot point now as today I am buying back my old 4719's. They're -10 point is 25hz. I run them with only the 30hz filter on the amp. I know from past experience with them that engaging the 40hz on the xover made an audible/tactile loss of low frequencies. I don't hear/feel the difference doing that with the 15's. All is right with the world again. Well, with the possible exception of my bank account. But hey, it's only money right? They print more every day. :)