One More Time: Running Distorted Tones Through a Tweeter

Discussion in 'Amps and Cabs [BG]' started by matante, Jun 4, 2019.

  1. matante


    Nov 3, 2003
    Explain this to me like I'm a five year old, please. Why do so many on Talkbass say you shouldn't run a distorted tone through a tweeter, while so many PA systems and home stereos are running distorted tones through tweeters?
  2. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Because generating a distorted tone from a bass creates a high amount of harmonics that may be several octaves higher than the fundamental. These harmonics, when reproduced at a high level by a tweeter are not very pleasing to most players and the power that these harmonics require in the band that the tweeter would reproduce is often more than the tweeter can handle. This is why distorted tone players generally turn the tweeter off, or use a cabinet without a tweeter. The natural rolloff of the low frequency driver filters the harmonics and is usually more musical sounding.

    The reason a hi-fi speaker does ok is because the bass has been recorded with the harmonics already rolled off (either by micing the low frequency driver or by using a cabinet simulation filter on the signal).

    I may have gone beyond the 5 year old stage here, but I'm sure you will have no problem with the information. Your question is actually a very good one IMO.
  3. matante


    Nov 3, 2003
    Makes sense. So you're saying that when a bassist runs the signal through a pedalboard to a DI box to the mixer, (no cab mic'ing) they're turning down the highs at the mixer? And does this mean that a bassist who only uses a drive pedal on one or two songs is going to go tweeterless because of those one or two songs?
  4. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    If a player sent me a distorted tone without any cab sim eq, I most certainly would need to eq to make the tone usable in the context of a mix.

    Using mild or moderate overdrive may or may not need the high freq rolled off, but this is quite different from what would be considered a distorted tone. Also, many distortion pedals do have HF rolloff as part of the pedal itself.
  5. matante


    Nov 3, 2003
    Thanks. By "distortion" I meant any kind of drive, distortion, fuzz, whatever. If it's common enough to have HF rolloff within the pedal, is it a mistake to suggest that you shouldn't run distortion through a tweetered cab? Maybe the advice should be not to run distortion through a tweetered cab unless you have the tone knob rolled down or your pedal otherwise rolls of the treble on its own.
  6. Wasnex


    Dec 25, 2011
    I think another factor is with many bass cabs there is a hole in the frequency response between where the woofer rolls off and the tweeter really starts playing (at least this is true for the off axis response). Next tweeters are often run fairly hot, because bass does not naturally produce a lot of energy above 3.5kHz where most tweeters play. If they are not run relatively hot, you probably won't notice they are even on. Also, the tweeter used in many bass speakers are not exactly of the highest quality; partly they are not rated for the level of power that can be generated when you run distortion, but many of them also have pretty jagged frequency response and don't sound particularly good when fed full range program material either. I suspect there may also be some issues with phase as well because it's fairly common to run the woofer full range and put an HPF on the tweeter, plus there is some physical offset between the woofer and tweeter which also causes additional phase errors.

    So when you run distortion through the cab, the tweeter really sticks out because suddenly there is a lot of energy, where previously there was very little. The extra energy can really emphasize the frequency response irregularities, level mismatches, and just general lack of the necessary engineering to pull it off gracefully.

    I haven't had a hard time getting a good sound running distortion pedals into full range flat response speakers. It does require setting the tone controls on the pedals a bit different than when you are using a traditional speaker though.

    Now the explanation for a 5-year old. Tweeters in bass cabs don't sound good with distortion because they are not made to sound good with distortion. I am sure @agedhorse could design a cab with a tweeter to sound really nice with distortion if he thought there was a good reason to do it. Unfortunately it would cost more money and people are probably not willing to pay extra. Although, for all I know, he may have already done so.
  7. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    It depends very much on the drive level, the degree of overdrive, the degree of distortion, the degree of fuzz because the "degree" very much influences the ratio of and the spectrum of the harmonics present in the signal.

    Many cabinets allow you to turn the tweeter down or off, this is another suggestion that I have made previously.
  8. beans-on-toast


    Aug 7, 2008
    Many cab have a tweeter on-off switch or rheostat to turn the tweeters signal level. It isn’t just to cut the highs, there are times that you don’t want a tweeter because of the signal driving the speaker.

    Some crossovers have a lightbulb for protection. Not something that you want to rely on when hitting a cab hard with HF signals. These can have a low pass filter that removes the harmonics. This helps.

    I’ve seen a lot of blown tweeters in bass cabs.
  9. Wasnex


    Dec 25, 2011

    Alternately if the cab sounds nice with the tweeter set relatively flat and can take the drive, the player will most likely adjust the pedals to give a sound that is more workable through the DI at FOH.

    When comparing a woofer/tweeter cab to a 2-way woofer/mid cab like the Baer ML212, I think most people will prefer distortion through the woofer/mid cab. Frequency response for the ML212 is 55-7kHz (-3dB).
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  10. BogeyBass

    BogeyBass Inactive

    Sep 14, 2010
    Cause the fizzle sizzle above 3k ish just sounds like pure krap with distortion

    And a bass tweeter crossed over at 5k
    Sounds like even more krap in general. Add distortion and it's pure garbage

    music through a stereo is for clarity to upper harmonics like cymbals or brass instruments or any high frequency.

    The distortion of guitars in music doesn't go much above 5/6k way Bellow the tweeter likewise a good producer has applied more filters to reduce that bandwidth in recordings

    If you used a final filter, or cab sim you could technically leave the tweeter on cause the filter would remove anything it would get.

    Well engineered distortion pedals already have final filters. But it still remains somewhat unseen in most.
  11. walterw

    walterw Supportive Fender Commercial User

    Feb 20, 2009
    in other words, at least with guitar those tones have already been run through a speaker and then mic'ed, or run through something to simulate being run through a speaker and then mic'ed, before they make it to the PA or to the recording.
    matante likes this.
  12. lz4005


    Oct 22, 2013
    Sounds like getting stabbed in the ears, also sometimes breaks the tweeter.
  13. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    I always send a signal to the board with the highs rolled off from 5k because I work with many sound techs and I don't trust them to do it. Sometimes I use a low pass filter pedal, sometimes I use a dirt pedal with the highs already knocked out for me. My board was so much simpler when all I had to do is throw my Heil PR40 in front of one of my tweeterless cabs, but I kept getting occasional sound techs that would put up a big stink about micing. So I just made my DI line sound as close as possible to a mic'ed amp, and cutting highs is a major part of how I did it.
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  14. I would prefer a 3-way : All coned speakers : (1) 18 crossing into (1) 15 into to (1) 12... All neo of course
  15. Wasnex


    Dec 25, 2011
    An 18 crossed to a 12 would be sufficient for me. Been there done that...but not neo.
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  16. Have run 4-12 Altec guit cab atop my 18
    Did not have crossover
    Result: heard 4-12 and “felt” 18. Due to being “Guitar” speakers they distorted in lower bass range.

    Had 4-12s not distorted I may have found my “ ideal” Prog tone set up Would have easily handled fuzz distortion overdrive w/o a horn. Although quite heavy to lift and transport.
    Wasnex likes this.
  17. BogeyBass

    BogeyBass Inactive

    Sep 14, 2010
    This could cause a possible derail lol

    It's like perfect bait.

    Unfortunately a 15 would cover the bandwidth that the 18 or 12 does. No benifit. 18 yes could go lower. But you need 8+ cubic feet for one driver. So you could get alot more drivers in that airspace

    The 18 in a ported application has the advantage of a lower reflex point or lower tuning possibility. But the required 5 to 6 cubic feet is still a ridiculous large cab for single driver to make it a feasible " portable" cabinet that is still limited to a 35 ish Hz tuning. And again lower SPL with single driver application . 2x 4x etc drivers being more beneficial in same airspace/ cabinet size

    Hence using 30 hz 15" and instead of wasting money on 3 drivers that offer no extra sensitivity or SPL

    Same money towards a 2x15 uses same airspace as one 18. And likewise ads more SPL for the money

    12 is still to large to improve off axis response. 15 covers same bandwidth
    And again higher sensitivity. Completely uneeded hence why 2x or 4x drivers is better. 2x or 4x 12" application is then benificial
    Last edited: Jun 4, 2019
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  18. Mmmmmm I understand the math but my ears aren’t so mathematically proficient...
    I own a 2-15 Kustom loaded with CTS; I’ve owned since early 1971 . Later I bought (2) Sunn 2-15 Magna cabs , which I sold as I was disappointed in their tone; sounded no better than my Kustom.

    In late 79 I bought a used Sunn 1-18VH which may have same sq inch as 2-15 and far less than (2) 2-15 cabs but my ears hear pure liquid ear candy from the 1-18 Cerwin Vega folded Horn than any cab I’ve ever heard ...... only thing better would be another of the same !
    mikewalker likes this.
  19. JimChjones


    Aug 6, 2017
    SE England
    Would it be fair to say that on a typical mid price bass system the tweeter tends to be a bit underspecified for a very HF rich signal, simply because that's not what it's designed for?
    And so that seems to suggest to me that if one were designing a system for a heavily distorted bass signal it would be advantageous to greatly increase the power rating of the system - double or treble the number of tweeters perhaps - and then modify the crossover network to dial back the treble response.
    It's something that interesting about music creation gear - if you look at frequency response charts for PA or HiFi flat is good, flatter the better, but that's not the case for music creation gear, which is commonly voiced. I've never really looked at frequency response charts, even where published, with the viewpoint of "what is the right shape to get the sound I want" but in a world where retail shops are disappearing perhaps we are going to need to.

    I suppose the problem is the complication. If a company is going to present cradle to grave ( instrument to audience?) frequency response charts for their gear, then it really would need to be there for every combination of amp and speakers, plus cover all the variations from the tone stage, and the result would be a bewildering assemblage of charts that a substantial percentage of the customer base would misinterpret.
    Do the likes of Mesa do this in house though? Do you have charts of what has sounded good, or is it easier to rely on experience?
    Last edited: Jun 4, 2019
  20. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    For very heavily distorted bass guitar, I don't think you would want tweeters at all because what they would reproduce (if they were sufficient specified to survive) would not be something most players (by far) would find very useful. This is just my opinion, but is seems to hold true in the real world.

    As far as voicing an amp, speakers, etc., I generally find it just as easy to rely on experience. Being a FOH guy, I get (or got) to hear a lot of world class bass players and while each is different in their own way, there are plenty of similarities too.
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