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Looking for Microbass Knowledge

Discussion in 'Luthier's Corner' started by Mark Wybierala, Apr 24, 2017.

  1. Mark Wybierala

    Mark Wybierala

    Apr 24, 2017
    Central NJ
    From the limited selection of available UBass or micro-bass strings, has anyone tried to use these strings on an instrument with a 24.5 to 26" scale?. This is the scale length of the average six string guitar. It is also the scale length of a cello 1/2 or 3/4 cello. You can buy a cheap imported student cello for under $200 on ebay and end up with a micro-upright bass if you had the right strings.

    I've been looking into this question for about two years now. I've been a luthier and professional stringed instrument tech for almost twenty years. In this time, I've built many short scale basses and have found that 30" is about the lower limit using conventional bass guitar strings and ending up with a functional electric bass.

    The UBass or microbass is really quite a cool instrument and has a place. The only reason it works is because of the availability of these new strings and the research going into the development of new and better materials and design of these strings. If you can get a low E at a 20" scale, it just follows that this can be done using a traditional six string guitar scale of 24.5 to 26". If the strings were available, it would probably devastate the market for the UBass but I don't see a reason why we shouldn't be pursuing something so obvious. There'd be no reason why the average intermediate skilled tech could not take any acoustic guitar and convert it into a bass. Is there anyone else here who is looking into this?
    indieandrew11 likes this.
  2. Will_White


    Jul 1, 2011
    Salem, OR
    I've thought of doing something similar but I haven't been able find any information on how they handle the extra tension that the longer scale will have. I have a 27" scale bass strung the bottom strings of a tapewound 5 string set that works well for upright-ish tones.
  3. Mark Wybierala

    Mark Wybierala

    Apr 24, 2017
    Central NJ
    I have a 1/2 size imported student cello that I recently repaired a broken neck on. I've ordered a set of GoldTone Silverback MicroBass strings and am fabricating a piezo equipped bridge for it. I did as much research on getting the strings as was possible with the level of information that the string manufacturers provide -- they do not provide much and you need to really dig to get anything useful for what I'm trying to do. From what I've read, the Aquila Reds, set 93U is good for a 26" scale but the price is too high to be buying these strings for experimentation. Aquila in Italy did not respond to any of my email inquiries but they are the parent company of the only manufacturer of a 26" scale bass using these strings. Before I install these GoldTone strings on the cello, I'd like to see if I can install these on a 25" scale acoustic guitar to see how it performs. I'll post what I discover. in another thread.
    RBS_Johnson likes this.
  4. marsbel


    Jun 21, 2006
    I'd be interested to see more about this.
    Last edited: Oct 15, 2018
  5. Beej


    Feb 10, 2007
    Victoria, BC
    Are there more than one kind of "Aquila Reds"? From what I can find, they can be picked up for less than $20 USD. Unless I'm looking at something else, that sounds perfect for experimentation... :)
  6. Mark Wybierala

    Mark Wybierala

    Apr 24, 2017
    Central NJ
    Yes there are at least three different sets applicable to this conversation - 91U, 92U, and 93U. The name Aquila Reds also seems to apply to a line of standard size ukulele strings so it follows that the name "Aquila Red" is not a reference to the material or string composition used in all cases. The set, 93U seems to be the string set for the ShortBass-One 14 which has a scale length of 26.4. I'm seeing prices of $50 to $60 for this set.

    I'm doing an awful lot of reading between the lines as I look into this. My conclusions may be fuzzy because I'm guessing and reaching to a large degree. There certainly is no string manufacturer who is giving any information up when it comes to luthiers and the creation or design of microbasses. I'm developing an idea that these strings are comparatively more scale specific. A conventional nickel/steel alloy.105 or .110 E-string is suitable for any scale length from 30" to 36" or more with a lot of latitude. I'm guessing that the synthetic composition or materials recipe required to create these microbass strings results in a string that has a very narrow field of functionality with scale length, pitch, and tension becoming a very precarious balancing act.
  7. Bruce Johnson

    Bruce Johnson Supporting Member Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Keith Horne and I are developing a mini-bass right now. It started out as a one-off custom project for a regular customer. He does a lot of flying to quick studio gigs and wanted us to build a little small-size bass for him that will easily go in the overhead compartments. He has one of those Japanese micro P-basses, which isn't bad, and he actually takes it to some gigs. We're starting from scratch on the design, the goal being to make the best sounding/feeling bass that we can within that external size envelope.

    As we roughed it out, we realized that there probably is a decent market for for them. So, Keith's looking at developing it out into a production model. It will be under his brand, Marvin Guitars, and following his styling. The working name for it right now is the Marvin Mini-Bass. It's going to use the same pickup and structural features as my AMB-2 Scroll Basses. We've settled on a 27" scale length, which is the longest that will fit within the envelope. The prototype is going to be all-walnut with a clear satin finish. We'll see where it goes from there. This is mostly Keith's project; I'm just helping with the engineering. We'll show more details when the prototype is done.

    Our bass is designed for steel strings; roundwounds initially and possibly flatwounds. We're having custom strings made up for it, at least initially. We'll be experimenting with gauges and types. They are probably going to be quite heavy, almost BEAD size. This isn't a rubber-band bass.
    mapleglo, tbrannon, nouroog and 2 others like this.
  8. HaphAsSard


    Dec 1, 2013
    From their blurb it seems the Red products at least share the principle of using variable density across gauges to keep diameters of low strings in check, and loss of flexibility with it, and achieve better tone consistency. For example they sell a red plain low G for linear ukulele tuning for those who don't want that string to be the lone roundwound in the set.

    By the way, if you can be swayed from synthetic - nylon or otherwise - core strings, there's also this set (steel core, stainless steel flatwound):
    MicroBass LaBella Flat Wound Strings | Gold Tone Folk Instruments
    They're good for up to 26" scale instruments according to reports. You may want a longer than usual tailpiece (EDIT: I suppose a longer tail-cord would suffice) to reduce string afterlength past the bridge. Speaking of which, it stands to reason that the same applies to mounting the Silverbacks on the 1/2 cello.
    Last edited: Apr 26, 2017
  9. Mark Wybierala

    Mark Wybierala

    Apr 24, 2017
    Central NJ
    When I've gone below a 30" scale length a few things tend to happen. This is what I've encountered.

    #1 is that the magnetic pull of the pickups start having a greater effect toward disrupting the natural vibration of the string and the closer the string gets to a strong pickup magnetic slug the worse it gets. This includes messing up intonation and getting a sort of warble in higher fretted notes. Pickups that have greater dispersion of the magnetic field are better and that includes pickups where the actual magnet is a bar attached to the pickup base. Pickups where the magnets are actually the pole pieces are worse.
    #2 is intonation issues (see #1) but if you can reduce the break angle at both the nut and the bridge (Saddles), the intonation become less of a problem. Try to get the break angles to the minimum required. I think that its a matter of the tension being less and not being able to pull the string into a straight line after it ramps up the saddle or over the nut. There's a resistance to going in a straight line -- think about how a nylon classical guitar string goes over a saddle and is immediately straight and the fact that classical guitars require little or no intonation compensation...
    #3 short scales just don't sound full. I think this is a bit to do with what I described in #2 but you can get a lot of improvement using taper wound strings. If you can reduce the diameter of the string when it goes over the saddle and the nut, the tone livens up quite a lot. I'm looking at a set of GHS strings called "Contact Core Super Steels" They're sort of a take on tapered wound strings. The problem is that you need to be lucky enough to have a bridge and tailpiece configuration that enables the area of the contact core to be going over the saddle. I've just taken the 105 E-String out of the pack (designated CC105) and the distance from the ball to the beginning of the winding is 1 13/16". I don't know if that is long enough if your using a typical string-thru Fender bridge for the contact core to be going over the saddle. Bridge saddles like a top loading AMB style single string saddle are going to have an awful lot of exposed core in the actual playing length. I don't have any idea of what the outcome from that would be.

    You can make your own tapered wound strings by unwinding the outer winding to the exact point you want. I did this for a telecaster guitar to bass conversion that I built using a 25.75 scale made in Mexico Fender Telecaster for a client with a disability/permanent injury. You just need to carefully cut the outer winding at the ball and unwrap the winding slowly by hand keeping it at a 90 degree angle to the string. You can choose to do just the outer winding or both of the winding layers up to the point you want and then you wrap cotton thread over the exposed end of the winding to securing it and saturate it with water-thin superglue. It works because neither the thread or the superglue have much mass to disrupt the natural vibration of the string and I've never had the winding come loose. Doing this made a night and day difference to the tone of the string and although the 25.75 scale bass fell a little bit short of sounding as good as a 34" scale, it wasn't actually all that bad and totally okay to gig with.

    I don't consider myself to be an authority on this subject but I've done a lot of short scale basses and the above it what I've observed. The whys and reasons for my conclusions might be flawed but I dig short scales because for me and a lot of people - especially kids learning, they enable me to play better and explore playing bass and having fun.
  10. Mark Wybierala

    Mark Wybierala

    Apr 24, 2017
    Central NJ
    HaphAsSard, I read about them but am concerned about the tension. One of my goals is to be able to modify any existing acoustic guitar into a bass. I've seen a lot of acoustic basses self destruct under the tension of bass strings so I'm sticking to the rubbery string idea. I have a 60s Yamaha orange labled FG-Junior with a beautiful solid spruce top and a 22.5" scale that would be an awesome microbass. I'm thinking of conversions of those wonderful Mini-Martins and Baby Taylors. Once in a while, I'll come across and old Gibson acoustic that needs a lot of work to the point that its almost a write off -- make it into a bass. Plug the tuner holes, install a laminate over the headstock, redrill for tuners and replace the bridge and you'd have something way cool.
  11. HaphAsSard


    Dec 1, 2013
    In short, you needn't be. (It's a bit complicated, so I'm more than willing to provide the complete steps of my reasoning if you prefer.)

    I've rounded the metal flatwound La Bellas' gauges up to the nearest common diameter and extrapolated from the tensions provided by D'Addario for their bass Chrome flatwounds in the same gauges, on their product pages (see here for the .05" and the .07") or tension chart (page 12, actually 11 of the pdf file, for the .09" and .11" which are available as singles - data in the chart are...dated, in part, but still useful as reference). In practice I look up or calculate the tension of each gauge at a 4th below standard (BEAD), which is darn close to what they would pull on a Spanish guitar scale instrument (capoing a long-scale bass at the 5th fret effectively makes it a standard-guitar, 25-1/2" scale bass, give or take a fraction of an inch).

    What I get is about 36 + 37 + 30 + 26 pounds = less than 130 lbs. The lightest acoustic guitar phosphor bronze set D'Addario makes, the EJ15 (.01–.047), has a total tension of 133.25 pounds. The obvious objection is that we don't know actual tension figures for the La Bella flats, but differences are bound to be within the realms of what is reasonable: even if you add as much as 7 pounds (which is more than plenty as a safety margin) to each string you still come up with less total tension than a .011–.053 acoustic guitar set.

    My take is that if a guitar can take a 6 string bronze set it can take the La Bella Goldtone flatwound short-shorts.
    (Of course, a 3/4 guitar has a shorter scale than 25.5", and so has a 1/2 cello, but the comparison I made, being apples-to-apples, still stands: you'd get less tension from both the bass and a guitar - or cello - set on those.)

    By all means keep experimenting with nylon core copperwounds or polymer strings if you're so inclined, but don't just do so out of concern for the structural integrity of the instrument IMO: those specific metal strings shouldn't really harm it. As for those ABGs you saw, those were ill-braced guitars with bass strings but also a bass neck and scale (34" or 32"): this makes a significant difference in terms of tension, which one step up in gauge and flatwound construction probably aren't enough to make up for.
    Last edited: Apr 27, 2017
  12. Hi,

    I've made "acoustic guitares to bass uke" conversion some years ago.
    I didn't found guitar scale polymer strings.
    So, i reduced the neck...to 21" and strung it with Pahoehoes.
    It's a good acoustic bass, but it could be great with a cello.

  13. Mark Wybierala

    Mark Wybierala

    Apr 24, 2017
    Central NJ
    Haph... thanks for doing some math for me. I try as much as I can to attribute the things I've leaned to scientific facts and methods myself. I've never done actual tension calculations -- more toward fuzzy ratios by the seat of my pants yet rational. I'm finding that this forum is truly a good one and I'm glad that I joined. Time after time when I google questions, this forum has popped up with more answers than any other place for bass guitar information. Its really silly that I didn't join earlier. I hope I can be a valuable member over time. My forte is fretwork and my skills at tweeking basses are really just borrowed from guitar work. A lot of things about guitars are applicable but there are things about basses that enter new territory. I play bass in an amateur band but to be honest, I'm really just faking it and getting by -- I'm adequate but still having a lot of fun. As a tech, when I setup a bass, I'm honest about this and do what I can to have the client come in and test drive the work I've done. I've found that bass players vary quite a bit more than guitar players to what they want from their instrument in terms of feel and response.

    Yea, I'm sticking to the rubbery strings. I don't know if they're just a fad that will fade away or not. The Ashbory bass really didn't catch on into mainstream. I just like the idea of being able repurpose acoustic guitars and I like the idea of a 25 inch scale bass for young people and as an instrument for guitar players who want to adventure into the deep. I've seen so many 34" acoustic bass end up as wall art and they're really not a very good instrument a lot of the time -- there are exceptions. I also need to consider that as a professional repair guy, I often only see the instruments with problems so my perception may be a little skewed.

    My GoldTone strings should arrive any day now. I hate waiting for lacquer to cure and I hate waiting for things to arrive in the mail.

    I'm very grateful for all of the responses. This is fun.
  14. Mark Wybierala

    Mark Wybierala

    Apr 24, 2017
    Central NJ
    I've been playing around with this 1/2 size cello... I put a 110 flat-wound string on it and the tone that I got was fairly decent considering the 22" scale. It was loud enough to play acoustically. It would work and I visited the D'Addario website and looked at their tension charts. This is a cheap Chinese import cello with a ply top so I'm thinking that the UBass strings aren't going to be very loud. My head then drifts toward the idea that I'm going to be focusing on the amplified sound from the piezo so I start considering the piezo configuration on this cellos bridge and then how the tone could be kinda bad and then thinking about how touchy the actual fingering positions are going to be in this fretless short scale for a guy who doesn't play cello in the first place. Playing a tiny upright bass on stage might be cute for a laugh but except for being able to do some very basic backup to country songs, I don't think that I'd actually use the instrument so I'm dropping the cello idea. If I want an upright, I'll build an electric one full scale so I stand a chance of being able to play it.

    The GoldTone strings are backordered from the manufacturer so I'm still looking into converting the Yamaha FG-Junior into a UBass and I'm still interested in rubbery strings that would be applicable to a 25" scale acoustic guitar.
  15. Harley Marty

    Harley Marty

    May 1, 2017
    Well Mark I just signed up to the forum to see if anyone else is playing around with cellos'. I'm on my 2nd instrument, a cheap full cello & put 1/4 size Thomastic double bass strings on it (dearer than the cello). I'm very happy with the sound of my Harley Benton fretless uke bass, but it is useless in an acoustic Irish trad session. I bought myself a Harley Benton resonator bass, the other guys can hear it out in front of me but I can't. I considered putting the silicone uke strings on a 1/2 cello but it can't be bowed ( I also have a 1/2 cello tuned GDAE octave below violin, or Irish tenor banjo tuning). The full size cello with DB strings is louder than the resonator bass (played with a pick), has a lovely tone like the use bass & I can back pack it on my bicycle to the sessions. To here it better I use a strap (look up Rushad Eggleston) even sitting! The next challenge is going to to be amplification. The bottom strings are going to need more boost than the high ones! The full size in a cello is good bit shorter in scale than 1/4 double bass. So many alternatives? Not an easy decision.
  16. Beej


    Feb 10, 2007
    Victoria, BC
    Somewhat relatedly, I had a cello years ago that I strung up with the heaviest strings I could find the music room and tried to play it tuned EADG. It was pretty floppy and could not project. I later was in Mexico and saw some nylon double bass strings and picked up a couple of packages, one of which I used on the cello and it worked much better. This was back in the early 90's and I sold that cello in about 98?

    This is the sister package to the ones I used...
  17. HaphAsSard


    Dec 1, 2013
    Let's assume the string afterlength behind the bridge on your cello is set in stone. (It is not, as I mentioned above: you could shorten it by using a double bass tailpiece, a longer tailpiece cable, or go the other way and design a smaller tailpiece for the purpose of having the strings attach closer to the body edge.)
    Step 1) - measure the distance between the string ball-end anchoring point at the tailpiece and the nut: this is your minimum length requirement (the string should not taper before reaching the nut, or at least the tapering should be very short, or you could have tone problems for open notes and of finger placement at the 1st "fret"; also, unless you want your open notes muffled there should be no silk, and you'd have to shave it back if there, on the string where it touches the inner part -towards the fingerboard - of the nut slot).
    Step 2) - measure the distance between the nut and the tuning posts closest to it: added to the other measurement, this is your maximum length requirement (the largest strings, meaning at least the E, string should taper before the post, so you don't risk breakage at the capstan by having the fat section wrapped around it at a sharp angle - the risk is somewhat reduced with roundwounds, higher with flats; lower the larger the diameter of the post.)

    Now, how about using bass guitar strings? Actual (full) winding lengths are usually 32" (and change), 34" and 36–38" (depending on manufacturer) for nominally short-scale, medium-scale and long-scale (30", 32" and 34") bass guitar sets respectively. (The reason for the difference between winding length and nominal scale should be obvious by now: the ball-end anchors at a certain distance from the bridge saddle even when top-loaded, so the full wound string has to be longer than the scale length of the instrument in order to reach the nut untapered. Of course there are short-scale basses that need medium- or even long-scale strings because they can only be strung through the body, or have a separate tailpiece.)
    If you verify that a given standard bass guitar string length fits the max and min requirements of the cello get a set, or (a) single E(/A) string(s) plus long-scale (A,) D and G, with that length, see if you like the tone and volume, rinse and repeat. Experiment with different types and brands. Bass guitar strings simply have a wider choice and lower prices than orchestral products.
    Last edited: May 2, 2017
  18. Harley Marty

    Harley Marty

    May 1, 2017
    Thanks Beej & HapAsSard, those strings are something to consider! The scale length of the now Bass is set at 28" (I shifted the bridge down 1") & the measurement from top tuning peg to the fine tuners is 38", so I put the strings from the resonator bass onto it. Harley Benton Strings aren't very good anyway & were terrible to bow, I'm sure quality guitar strings say 120 for E could sound better and louder (I've a130 on one guitar with a 23" scale tuned to F). The double bass strings sound great on the G & D, good on the A & acceptable on the E. The E being the closest I can pluck it with 2 fingers. I'm only a hack player anyway so it's all a bit of fun:) & a lot more fun when I can hear myself. The Irish guys are good at their music & the formula is simple enough. To the crowd the difference between a good & mediocre player is 2 pints of Guinness. Having a small base in a crowded pub session is a godsend so to go for bigger sound means pick-up, pre-amp & Bluetooth speaker. I've been using a Kitsound hive2 through a Palmer mk11 pre-amp (headphone out) with amazing results for my tenor guitar. The bass pick-up selection will be tricky!
    Ps I'm usually seen playing accordion, flute, C tenor, C soprano saxes so I'm used to the loud things in music. Any pick-up suggestions?
    HaphAsSard likes this.
  19. Mark Wybierala

    Mark Wybierala

    Apr 24, 2017
    Central NJ
    I have a decent but beat up german-made full size cello that is missing its fingerboard and I have one that I could install. But I could also remove the neck and make another custom neck for it resulting in a 34" or longer scale length. I'm not now or ever will be a cello player. It wouldn't be a problem to make a neck better suited for playing bass in a cover band. I could even include a trussrod, and employ a 7.5 or flatter radius with inlayed markers. It would make it not appropriate for using a bow but I don't see myself using a bow. So many instruments and evil ideas... so little time.
  20. HaphAsSard


    Dec 1, 2013
    (Sorry if I skip the pickup question: I know next to zero about bowed instrument amplification. I'll concentrate on acoustic volume since I guess in your case there'll always be situations - informal sessions, last minute rehearsals, very small gigs - in which you forgot to carry an amp and still need to be heard.)

    A custom string set with the following gauges
    .13/.125 - .09 - .07/.065 - .05
    would be balanced and nice n' tight but not overly so (total tension would be a little higher than those of heavy cello sets).
    Mind you, I've never held a bow in my life so I have no idea which types of strings work fine when bowed and which don't. Within the above constraint, in your situation look for brighter strings: e.g. if roundwounds are not an option a custom set of D'Addario Chrome flatwounds may be worth considering (they do become darker with age but depending on your skin chemistry you could get many months of usable life out of them). Do you live in Europe?
    D'Addario - Bas > Enkele snaren
    The missing D and G can be found here, at a substantial cost I'm afraid:
    D'Addario Artikel im SAITEN E-Bass Einzelsaiten Flatwoundshop kaufen bei SchneiderMusik.de - Schnelle Lieferung - nur 99 ct Versandkosten!
    or replaced with guitar Chromes (.065 and .052), which in my experience sound phenomenal for bass:
    Single Strings - D'Addario Flatwound Single Strings - Single Strings for Electric Guitar
    Ernie Ball is another option:
    Ernie Ball Elektrische bassnaren kopen? | Laagste prijs garantie | Bax Music

    The other type of flats EB makes, the Slinky Flatwounds (AKA cobalt flats), are super-duper bright and would be interesting to try on an acoustic instruments but sadly don't come as singles.
    From a volume standpoint rounds would be your best bet, but again I don't know how they fare with bowing.

    One more thing: thanks for mentioning that your downtuned cello is louder than the resonator bass. I'd have thought the opposite, and in the past I've repllied to some posters with similar requirements as yours (acoustic volume, portability, more need for cutting through than audible fundamental frequencies) pointing them to resos.

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