agedhorse Posted December 9, 2021 Share Posted December 9, 2021 9 hours ago, Lfalex v1.1 said: I had a QSC PLX1202 power amp. It had dip-switches for an HPF ( on/off, 35Hz/50Hz -3dB 24dB/ octave roll-off) This afforded me the opportunity to experiment. The 35Hz setting helped a lot. Cleared out a lot of "congestion" from the sound, and audibly decreased the stress in the sound from the cabinet, while also tangibly increasing headroom. I was reluctant to use the 50Hz setting, as it's below the fundamental of even "E" (about 41Hz). Turned out it was even better, despite supposedly being above the lowest frequency the cab could supposedly output (but no dB reference point was given!) IIR, the choices are 30Hz and 50Hz, the slope is 18dB/octave. For large bass reflex sub cabinets, the 30Hz HPF works well. For the other applications, 50Hz works well. 1 Quote Link to comment Share on other sites More sharing options...
Lfalex v1.1 Posted December 9, 2021 Share Posted December 9, 2021 Ah, forgive the vagaries of my memory! 1 Quote Link to comment Share on other sites More sharing options...
Lfalex v1.1 Posted December 9, 2021 Share Posted December 9, 2021 (edited) All this now makes me wonder... Do they use Low Pass Filters to suppress noise above, say 16kHz. Nothing up there but hiss and electrical noise. Edited December 9, 2021 by Lfalex v1.1 Quote Link to comment Share on other sites More sharing options...
Count Bassie Posted December 9, 2021 Share Posted December 9, 2021 (edited) 33 minutes ago, Lfalex v1.1 said: All this now makes me wonder... Do they use Low Pass Filters to suppress noise above, say 16kHz. Nothing up there but hiss and electrical noise. I suppose you could, I've only heard of them for musical applications though. Like, if you don't want the extra-bright shimmer at the top end of your sloppy fingering to come jamming it's jagged shards into your listeners' ears. 🤭 But hey, frequencies are frequencies! (Just trying to have a little fun here!) Edited December 9, 2021 by Count Bassie Quote Link to comment Share on other sites More sharing options...
Lfalex v1.1 Posted December 9, 2021 Share Posted December 9, 2021 48 minutes ago, Count Bassie said: I suppose you could, I've only heard of them for musical applications though. Like, if you don't want the extra-bright shimmer at the top end of your sloppy fingering to come jamming it's jagged shards into your listeners' ears. 🤭 But hey, frequencies are frequencies! (Just trying to have a little fun here!) Sloppy fingering? Your words are meaningless to me... Quote Link to comment Share on other sites More sharing options...
Count Bassie Posted December 9, 2021 Share Posted December 9, 2021 15 minutes ago, Lfalex v1.1 said: Sloppy fingering? Your words are meaningless to me... I didn't mean *yours*! 1 Quote Link to comment Share on other sites More sharing options...
Al Krow Posted December 9, 2021 Share Posted December 9, 2021 1 hour ago, Lfalex v1.1 said: All this now makes me wonder... Do they use Low Pass Filters to suppress noise above, say 16kHz. Nothing up there but hiss and electrical noise. Most of us lose the ability to hear much past 14kHz as we get older. The higher end range 5kHz to 10Khz is nice to have if you're after a bit of high end 'zing' e.g. on slap bass. Quite a few cabs will do the job for you e.g. the BF Super Compact and ST have a "usable frequency range" topping out at 4kHz - too 'flat' me for personally hence my switching to the the BB2, but plenty of SC / ST fans on here. Some amps make a thing of providing the option of a more vintage tone with a tailored LPF e.g. the VLE dial on Markbass amps (and which can simultaneously. deal with annoying tweeter hiss present on some MB cabs). Quote Link to comment Share on other sites More sharing options...
agedhorse Posted December 10, 2021 Share Posted December 10, 2021 9 hours ago, Lfalex v1.1 said: All this now makes me wonder... Do they use Low Pass Filters to suppress noise above, say 16kHz. Nothing up there but hiss and electrical noise. Yes, LPF elements are used throughout audio circuit design. Not just for bandwidth limiting but also for stability management reasons. 1 1 Quote Link to comment Share on other sites More sharing options...
Beer of the Bass Posted December 11, 2021 Share Posted December 11, 2021 I've been experimenting with an LPF recently (a Schalltechnik Vong HPF +LPF pedal) to tame the extreme highs from a fuzz pedal I use. The fuzz sounds great through a tweeterless cab, but with a bass rig with a tweeter or through a DI, it's hard to manage. Though the Markbass VLE control also does that quite effectively the times I've used them. 1 Quote Link to comment Share on other sites More sharing options...
dabis Posted December 19, 2021 Share Posted December 19, 2021 (edited) On 08/12/2021 at 21:13, chris_b said: The obvious benefits of an HPF have interested me for awhile. A few years ago I borrowed a Thumpinator and used it with an Aguilar TH500 through 2 Berg AE112's. I noticed very little difference with and without. I didn't see any change in the movement of the cones. At the moment I'm running a Berg Forte HP through a Super Compact and sometimes with a Super Midget as well, and I still don't hear the HPF making much of a difference. The point where I can hear the HPF working it's changing the tone in a very unpleasant way, making it thin and nasty. Is the HPF doing its job when I can't hear it? How do I know if it's doing anything useful not? I measured last year some stuff of my chain. My Aguilar Tone Hammer 350 (the preamp is the same of the 500) has an HPF fixed at 20Hz, -3dB, slope is something between -6dB and -12dB/octave (if my vision is correct here). ARTA software graphic pic attached. We maybe aren't hearing if the HPF is doing something because it's working below our hearing capabilities. Edited December 19, 2021 by dabis Grammar correction 1 Quote Link to comment Share on other sites More sharing options...
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