Guitar frequencies Vs. Amp woofers and tweeters

Discussion in 'Amp Central Station' started by DugT, May 11, 2019.

  1. DugT

    DugT Tele-Holic

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    I've been reading about guitar frequencies and speaker drivers because I'm considering getting a powered speaker cabinet. Here is some interesting frequency data that is new to me.

    1. The fundamental frequencies in the playable range of the typical, in-tune electric guitar covers the range from about 80 Hz to about 1200 Hz. (That is much lower than I would have guessed.)

    2. The frequency range relevant to electric guitars, which is similar to a regular woofer type driver, is approximately 75 Hz to 5 kHz. That is the more relevent data.

    Most PA speakers have two drivers and the crossover is around 2 kHz to 2.5 kHz. This implies that the tweeters are better than woofers at 2.5 kHz and up. By "better" I mean more accurate or precise or both. This may or may not be better for guitar tone. I suspect it isn’t better or guitar amps would include tweeters. Tweeters are pretty cheap but then a crossover is required too. Anyway, if tweeters in guitar amps were better I suspect they would have them, at least the more expensive ones would. But a lot of guitarists play through PA's or their own PA speakers which have tweeters and they like them. I suspect good PA speakers may sound more like reference speakers.

    Yes, I'm thinking out loud. Please feel free to join in.
     
  2. Dacious

    Dacious Poster Extraordinaire

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    The problem with your reasoning is twofold: PA speakers are designed to develop volume for a music source. For a long time there's been the ability to plug straight in to a PA via an effects unit, modeller or emulator. And yet most touring musos don't. They still use an amp, which is micc'd if needed for volume.

    That's because the amp is part of the music source.

    Lots of things sound great 'in theory' . Practice is something else.

    If you're doing acoustic a PA can can be fine. If you're going to use a speaker for a modeller output, the modeller is already emulating the effect of a guitar amp being micc'd.

    Part of the distinct tone of a guitar amp is the non linear frequency response of classic amps and their signature speaker.
     
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  3. DugT

    DugT Tele-Holic

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    Did you mention the problem with my reasoning? If you did, I didn't notice it. Maybe you made some false assumptions about my intentions.

    By the way, I will be plugging my multi effects processor, a Boss GT-100, into a PA speaker that I'm planning on buying; either an Alto TS212 or a TS215. The 15" speaker vs 12" question led me to research guitar frequencies hence my post.
     
  4. jrblue

    jrblue Tele-Afflicted

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    I don't know if these thoughts help, but here goes: Most guitar amps are not designed to simply reproduce the frequencies generated by the string and pickup. Both the signal chain and the speakers directly shape the sound we hear and that we think of as "guitar tone." For instance, a Champ with it's 8 incher produces a different balance than a 1x12 combo. Most people do not like the "pristine" sound of guitar frequencies as delivered by small speakers. I'm an old guy and remember when crossovers and tweeters and even horns were marketed as tonal improvements in speaker cabs. That's when the term "ice pick" became popular, and when small speakers and horns blew all the time -- resulting in a better sound than when they worked. Of course, we have excellent high-power small speakers now. And tastes change. But I'll be at present more people prefer the more familiar sound resulting from conventional guitar amplification/speaker matching.
     
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  5. JD0x0

    JD0x0 Poster Extraordinaire

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    You don't want tweeters with electric guitar, because everything over 5khz (or even 4khz) starts to sound really harsh, when you start to introduce overtones from distortion. 6khz-10khz, is only unusable on electric guitar because it's painful with distortion. People also forget about subharmonics. Subharmonics can be produced by signal amplification through loudspeakers.
     
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  6. Dacious

    Dacious Poster Extraordinaire

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    Well, if you were just doing stream-of-consciousness stuff then that's not reasoning I suppose. I wasn't having a go so much as pointing out there's reason we don't use full range speakers in guitar amps.

    I guess my statement could be encapsulated in saying the amp is part of a sound or tone. I'm not familiar with the Boss, but even if it 'emulates' a special particular amp tone, it may not emulate a complete amplifier. It might be designed to give a neutral sounding amp a Twin Reverb flavour, or a taste of Plexi. But still through a guitar amp (I presume).

    Whereass such things as Kempers, Fractals, et al are designed to model the complete amplifier including preamp, Poweramp and speaker cabinet. So if you did a blindfold taste test you would struggle to pick from the real thing.

    As such they're designed to go through a PA or presumably their own output engine which does not flavour the result. You aren't getting powertube or speaker breakup - in fact the protection circuits are designed to stop feedback which Class-D stuff doesn't like.

    Out of such, it won't use the tweeter much if at all. Because as JD0x0 says you don't want some noises amplified. It's own filters will cut response in that range.

    The other issue with using biamped speakers which is what you are speaking of, is even in the best crossover design there's a loss - the point where the resistor drops the highs to the woofer and cap drops the lows to the tweeter.
    n160fig5.png
    And even the theoretical optimal design may miss that at say 2 5khz the efficiency and ability of the woofer and tweeter to replicate tone@power may not be equal. IOW there's frequently a dip or mini peak in a particular band which may not be analgous to a guitar speaker. The further you push a guitar speaker high, the more it will attenuate frequency.

    A manufacturer will come up with a compromise - but a compromise between response curves and filter behaviour. And - designed to be flat and high fidelity. Often not what week seek in guitar.

    Then you have the properties of acoustically efficient plastic boxes for PA flat response vs un--acoustic open back cabinets in pine or closed cabs in ply. Not really similar.

    All you can do is see if your proposed chain will deliver what you want.
     
    Last edited: May 12, 2019
  7. DugT

    DugT Tele-Holic

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    Thanks for that info about the evolution/history of guitar amps and add me to the list of people who don't like small speakers in guitar amps.
    You might be able to answer this question. My Boss GT-100 has about 20 amp emulations. Is it designed to work with and FRFR, for example? I would think the designers would want it to work with a wide range of amps and an FRFR would be the least idiosynchratic. I'm assuming a PA speaker is designed to be more FRFR than a typical guitar amp. By the way, I have my GT-100 start to cut off the higher frequencies at 6.3 kHz. Also, I would be happy with a powered speaker without a tweeter but I haven't found any. I'm hoping a good PA speaker will sound good if I cut off the highs. I've read a few reviews that are real happy with PA speakers used with their multi-effects processors.
     
  8. DugT

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    Do speakers actually help produce subharmonics or do they just speak them? Are you saying that tweeters cause more subharmonics or they just make them more annoying?
     
  9. schmee

    schmee Poster Extraordinaire

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    Actually, woofer/horn pa cabs sound pretty darn good for guitar. But a balanced more accurate tone is not what many guitarists are looking for. otherwise we'd be playing 1000 watt SS amps. I will say that piezo or other horns with small diaphragms are not a great sound to my ears, regardless of whether it is voice, guitar or whatever. (thus the Bose system) There are guitar amps with woofer tweeter etc, mostly for acoustic or jazz.
     
  10. DugT

    DugT Tele-Holic

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    I understand what you are saying. It seems to me an equalizer, which my GT-100 has, could help aleviate some of this. Do you think people shouldn't use muliti effect processors? If they are acceptable what kind of speaker arrangement would they work with best? If the crossover is such a problem, why do FRFR speakers have at least two speakers and a crossover circuit?

    One of my reasons for exploring getting a PA speaker is I don't really need both a modeling amp and my effects processor. I prefer the processor and I'm hoping a powered speaker with less flavor.
     
  11. Dacious

    Dacious Poster Extraordinaire

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    I use a Line13 stompbox modeller so no I am not against their use.

    I just read up on the Boss - it appears to be similar in purpose with some additions. It models effects but it does also model amps.

    It can be placed in front of a PA speaker. But most people seem to plug it into an amp or in the effects loop.

    It isn't really designed to replace a guitar amp.

    You can indeed plug it straight into a PA speaker - no law agin' that.

    Only you can decide if the results are acceptable.

    Your money and choice. If you wanted a solid-state guitar amp, good ones're available for reasonable $$$. Vox, Marshall, Fender all sell them. Or something like a Quilter or Roland Cube.
     
  12. warrent

    warrent Friend of Leo's

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    You want the tweeter. But let's back track a bit. A guitar amp uses a specific speaker to create a sound. That speaker becomes part of the guitar signal chain and using different types of speakers we can help create the tone you want, be it Jazz, Blues or Death Metal. However when we often discuss a certain players tone we are often listening through a home stereo system or the house PA at a large venue. In both cases your hearing the players total sound through a woofer and a tweeter at the very least. The same goes for the monitors used in recording.
    In your case the Boss Unit is creating the complete sound including the amp cabinet so what you want the fffr speaker to reproduce that sound accurately. To do that you really need the woofer and tweeter to capture the sound the tweeter will add air and space around the reproduced sound and accurately reproduce the high frequencies from the guitar.
     
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  13. DugT

    DugT Tele-Holic

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    Based on the info I learned from the helpful posts here and another thread, I bought some studio monitors today and I love the tone. I should because they originally sold for $800 but I got them for half that. The monitors have 8" woofer and tweeters and there is also a 10" subwoofer that is good down to 40 Hz. I thought the subwoofer might be useless but it makes an nice difference to the lowest notes. Playing in stereo probably makes the biggest difference but it probably helps that they are closer to FRFR and better quality in everyway than my amp and speaker. The monitors are JBL LSR2310SP and LSR2328P.
     
    Last edited: May 13, 2019
  14. philosofriend

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    Powered speakers that I am familiar with have closed enclosures and try to get as accurate a bass as they can get (except the Mackie thump series with their exaggerated bass response). When you play a guitar through a good modelling system into one of these, the lowest notes on the guitar and the thump of the pick on the start of each note just doesn't sound like a guitar being played through a guitar amp. Real guitar amps reproduce the lowest notes on the guitar but they just don't make the thick thumping noises on the attack of each note.
    Open back amps can't play the sub-guitar tones because the bass coming out the back cancels the bass coming out the front. Marshall-style amps kill the lowest frequencies by a capacitor in series with the signal, so they sound great with closed-back speakers.

    Different players at my church have played with a modeler through a powered speaker and it tends to murk up all the other instruments in the lower midrange. Whereas a real guitar amp can cut through a mix without fogging up other instruments. You can do whatever you want with an equalizer, but the speaker is still going to try to do what it is good at, which is make low sounds.

    Les Paul liked his guitar sound as high fidelity as possible. He liked to record straight into the board and he used low impedance pickups that gave a high fi sound and couldn't be plugged straight into a normal guitar amp. Gibson made a couple of models having his type of pickups, but they never sold very well. Listen to his recordings and see what you think.

    I've been forced by equipment malfunctions to play solid body guitar live through a PA a few times. Distortion sounds horrible, everyone in the band looks at you like "stop that RIGHT AWAY!" The clean sound is very weird, you can get musical results but lots of stuff that normally sounds great doesn't work at all. You have to play precise, simple and controlled. I never had the desire to keep playing that way. I can see though, how a person (like Les Paul) might find it a good musical challenge.
     
  15. DugT

    DugT Tele-Holic

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    Thanks for trying to convince me that my new speakers suck. ;)

    I don't play in a band and probably never will. According to the recent poll, "Do you play in a band..." I'm not the only one. So, not everyone is trying to cut through a mix.

    For forty years I played only acoustic guitars without an amp influencing any of the range so maybe that's why FRFR sounds good to me.

    Supposedly, multi effects processors sound better through FRFR amps. It makes perfect sense that a neutral amp would sound best with an amp emulator. Mine sounds substantially better through the two studio monitors that I tried with it. This is compared to my Katana Artist.
     
  16. BigDaddyLH

    BigDaddyLH Telefied Ad Free Member

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    Those are the *fundamental* frequencies of the notes. Not counting harmonics, a 24-fret guitar has a range of 4 octaves, and frequency doubles with every octave so those numbers are what you should expect:

    82Hz = E2 (low E string)
    165Hz = E3 (D string, 2nd fret)
    330Hz = E4 (high E string)
    659Hz = E5 (12th fret)
    1319Hz = E6 (24th fret)

    What's missing on the high side are the overtones of the notes. The second octave over E6 takes you to 5274Hz.
     
  17. Artunes

    Artunes Tele-Meister

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    I'm glad that it worked out for you. I am not familiar with the Boss GT-100, but I do use a Boss ME-80. On my unit, it has the various amp models in the pre-amp section, but it also has a mic'd speaker emulation that is activated by plugging something (a dummy plug or some ear buds) into the headphone out jack. That makes a big difference when plugging straight into a PA.
     
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  18. DugT

    DugT Tele-Holic

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    You only quoted my point 1. Just below it was my point 2.

    "2. The frequency range relevant to electric guitars, which is similar to a regular woofer type driver, is approximately 75 Hz to 5 kHz. That is the more relevent data. "
     
  19. BigDaddyLH

    BigDaddyLH Telefied Ad Free Member

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    Yes, I agree. I was just starting with the physics of the guitar.
     
  20. gusfinley

    gusfinley Tele-Holic

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    Take a 3-way Home Stereo speaker with adequate power handling and hook it up to your guitar amp.

    Allowing the guitar amp to distort = 30 second lesson on why electic guitar amplifiers DON'T have any high-range speaker options!
     
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