Any banjo players out there?
Adventures with 'other' instruments...
Jalan Crossland is an absurd talent
Forum Activity for @nate
Any banjo players out there?
Adventures with 'other' instruments...
Melvoid:
Hi, My main instrument is the 5-string banjo. I recent did a book for Hal Leonard called Do-It-Yourself Banjo. Written during Covid, it's sort-of intended as a self teaching guide, complete with audio and video files to demonstrate what's being presented in the book. Been teaching since the mid-1970s, so feel free to hit me up with any questions. Naturally, I recommend the book, but I have been getting good feedback about it.
Thank you for your offer I appreciate that. So far so good but if I have any questions I'll definitely take the opportunity to ask.
steve104c:
Nate. You have a cool Uncle. That is a nice looking banjo. Last year bought a Deering Goodtime 2 banjo and later bought the Deering Goodtime Banjo/Ukulele. Love it. Easy to play and sounds a lot like a banjo.Steve B.
Those banjo-leles seem like a lot of fun. I just got everything I need to make myself a banjo drumhead, and a banjolele is going to be the first thing I try making.
motormike:
If you're reading this, and you're a banjo fanatic,
there's a player you should seek out named Kyle Tuttle.
He and I shared a few motorcycle rides, and lived only a couple blocks apart.
A simple google search of his name will bring up a nice overview of his work.
That is very cool! I did not know his name, but I'm a big fan of Molly Tuttle with Golden Highway, which he is the banjo player for. Definitely an extremely talented and entertaining banjo player. There seem to be a lot of very talented banjo players coming out of the modern "folk punk" bluegrass scene. A few that come to mind are Billy Failing, Jalan Crossland, Matt Heckler and now, Kyle Tuttle
Nate
updated by @nate: 02/02/24 06:24:17PM
Intonation Problems
Instruments- discuss specific features, luthiers, instrument problems & questions
Dwain Wilder:
Some builders do build flat fretboards. When there are as many frets as the dulcimer has, though, the problem of getting the lowest action becomes very much like that of designing auditorium seating.
Imagine an auditorium in which the seating floor is flat: even if everyone is the same height, people will have trouble seeing over the heads of those in the next row. And in the foremost rows (that cost the most to get), you begin to see less and less of the performers!
So the answer is to make the floor a long sweeping curved surface sloping gently down, each row a little lower than the one behind. That works well until about 2/3 down toward the stage: at that point the person in the next row are no longer the issue. Now the problem is that you can't see all of what's happening on-stage. So the floor has to start to rise so each row is a bit higher than the one before. Then each person can see everything on the stage.
So think of the string's "line of sight" as it is fretted at each fret, and design your fretboard so that, at each fret position, the height above the further frets is equal. If you're good at trigonometry you can solve the problem as one of the string forming a constant angle when fretted at each angle such that the sine of the angle is just a bit greater than the top of the next fret's crown. Since the distance between frets is exponential, that fretboard surface will be very interesting mathematically. (I've never done it mathematically. I prefer the heuristic method in instrument building, not analytics —except in the matter of setting frets in equal temperament).
This is very insightful I did not know about that feature. Thanks for the information,
Nate
Intonation Problems
Instruments- discuss specific features, luthiers, instrument problems & questions
Dwain Wilder:
Every dulcimer will have its own fingerboard 'profile,' meaning a concave 'dish', though some makers prefer to build with a flat fingerboard, I hear.
Dwain, could you please explain this more, I was not aware of this. I have only built with flat fingerboards so I'm having a hard time understanding what you mean by 'concave dish.'
Thanks
Nate
updated by @nate: 02/01/24 08:43:05PM
Intonation Problems
Instruments- discuss specific features, luthiers, instrument problems & questions
Three dimes seems like a TON of extra height by the nut. I hope that isn't due to warping or bowing.
If you have a nice straight edge on a metal yardstick or something like that, you could set it along the fretboard and observe if the straight edge touches all the frets, or if some of them are lower/higher. It is possible that some frets have risen slightly out of their slots and need to be 'tapped' back into place.
It can be helpful to check each fret with a tuner and note how out of tune each fret is. If the first couple of frets are the most out of tune, the issue is most likely your nut being too high. If the frets get more out of tune as you get closer to the octave, you most likely need to move or reduce the height of your bridge.
Once the frets are all level and the action is correct, you will most likely have to readjust your bridge placement anyway.
Tune the string up to tension and get it exactly to the desired note. Use a tuner to compare the open string to the note at the 7th fret (octave) If the octave is flat, the bridge needs to be moved *closer to the nut* If the octave is sharp, the bridge needs to be moved *away from the nut*
instrument question- Stephens Lutherie/holy grail dulcimer?
General mountain dulcimer or music discussions
Bob Stephens dulcimers are absurdly cool. I haven't had the privilege of playing one but the engineering is fascinating and the tone is definitely distinctive. They incorporate a lot of design elements that you won't find in any other instruments. They may look 'guitar-like' but they are very optimized dulcimers. Features like the floating neck and internal soundboard are examples of taking things that are distinctive about a dulcimer and pushing them further.
John Molineux box dulcimer
Instruments- discuss specific features, luthiers, instrument problems & questions
Strumelia:
ok so it's the fret pattern, not technically the 'pegbox' or tuning mechanisms that are opposite mirrored for duet playing. I was just assuming the peghead was usually at the 'fret 1' end of the fretboard, but there's nothing saying you can't put the tuning pins at what we consider to be the tail end of the box.
I saw a courting dulcimer on this site years ago and haven't been able to find it since. It had fingerboards that did not extend to any edges of the box, and both pegboxes were on one side of the instrument. When I realized that the fingerboard doesnt need to go all the way to the box edges, and that the pegbox can be at either end of the strings, I made this dulcimer
updated by @nate: 02/01/24 05:50:11PM
John Molineux box dulcimer
Instruments- discuss specific features, luthiers, instrument problems & questions
The dulcimer played by John in the video does not seem to be a courting dulcimer, like the one in the patent document. The fingerboards are both facing the same way, and don't seem to be laid out in a way that would be easy for two people to reach both fingerboards at once. The fact that it is only one octave is the main reason I am guessing that John's second fingerboard is for lower pitch notes. It would not need the second octave, since the higher notes are already on the other fretboard.
John Molineux box dulcimer
Instruments- discuss specific features, luthiers, instrument problems & questions
The dulcimer in the video is very cool and relates to some ideas I've been thinking about lately (such as fingerboards that do not touch any edges of the instrument)
It's hard to imagine what aspect of that dulcimer would be patented. It is notable that the second fret board does not have strings or a bridge. My first guess would be that it is intended to have a lower register of deeper pitch strings. This seems likely, since it only has one octave worth of frets.
Another guess would be that the second fretboard is meant to play in a different key. Bing Futch has a Folkcraft dulcimer with two separate fretboards in different keys.
Either way thanks for sharing
Nate
New instruments that I have no clue about!
Site QUESTIONS ? How do I...?
These are undeniably super cool. I am grateful that you shared these, but I would think the best person to tell you what they are would be your grandfather himself? The first instrument is very cool to me due to its fret layout. It is interesting to think about why the second string would be chromatic and not the first. Maybe it would allow the second string to be tuned to a major 3rd and still play diatonically.
Would love to know if anyone knows more about the bizarre fret layout on the first photo. It reminds me of a citera.
Thanks
Nate
updated by @nate: 02/01/24 03:47:49AM
Reasons NOT To Get a Chromatic
Instruments- discuss specific features, luthiers, instrument problems & questions
#1 Reason NOT To Get a Chromatic Dulcimer:
You don't have to defend or rationalize it's place as a dulcimer.
Vintage dulcimer information sought
Instruments- discuss specific features, luthiers, instrument problems & questions
I agree that the wood piece is meant to simply space the strings at the correct distance from eachother, and the dark colored 'bar' is the actual bridge. It would explain the extra notch. That would correspond to a "course" of melody strings, it if were strung '3 string equidistant with a melody course.' From the image, the dark colored 'bridge' seems to straddle the fingerboard, with small 'legs' that go down off both sides. I assume that piece of light colored wood was added specifically to modify it to be able to play 3 string equidistant.
Out of curiousity, I'd love to know how much this dulcimer cost at an antique shop.
Look forward to you learning more about it and sharing with us
Nate
updated by @nate: 02/01/24 02:23:22AM
Reasons NOT To Get a Chromatic
Instruments- discuss specific features, luthiers, instrument problems & questions
Ken Hulme:
If it has more than diatonic frets, or more than 3 courses of strings, technically an instrument is no longer a dulcimer, it is a Fretted Zither. "Tomay-to tomaatoe", but diatonic fret spacing is part of what defines a dulcimer.
I'd love to find the first man to call an Appalachian zither a 'dulcimer' and ask him his definition. I wonder if it would be so general that most modern instruments fit in, or so strict that none of us meet the cut.
I think the standards you apply to dulcimer are not be applied to other instruments. A seven string guitar is a guitar, and a micro tonal guitar is a guitar.
In my view, a dulcimer that is different is just a dulcimer with qualifiers. Whether a chromatic dulcimer, a 1, 2, 4 or 5 string equidistant dulcimer, a resonator dulcimer, a lego dulcimer, they all count as dulcimers, but are not simply a dulcimer.
Might not be 'just a dulcimer' but it's 'more a dulcimer than it is something else.'
Just For Fun - sayings regarding the dulcimer or music
OFF TOPIC discussions
Ken Hulme:
@shanonmilan --the vast majority of us (traditionalists and moderns) play dulcimer horizontally -- "string side up" on our laps or on a table or stand. There are a few who play it more vertically -- like a guitar...
I play behind my back, Like Stevie Ray Vaughn.
I like to leave my best performances behind me
beginner strumming
General mountain dulcimer or music discussions
In my opinion, in and out strums sound very different, especially if you strum slower. I feel that they have different energies. An in strum feels passive and calm whereas an out strum feels engaging and sharp. I think that a melody note after a bass note feels cradled, whereas a base note after a melody note feels like an echo. So I think it would benefit you to make sure you play plenty with both in and out strums, and feel the subtle difference.
Good luck and have fun
Nate
Looking For Tuner Recommendations
Instruments- discuss specific features, luthiers, instrument problems & questions
I highly recommend trying an app called "soundcorset" it is very straightforward to use for tuning, and most modern smartphones have significantly higher quality microphones than clip on or onboard tuners.
The advantage of a clip on is that it doesn't pick up background noise, which is useful in loud places like group settings. As John said, a chromatic is definitely ideal.
While I can understand the apprehension toward using an app, the key benefits are that it's free and that it's built into something you already carry. Personally, I keep losing my tuners around my apartment, because I have too many instruments that arent well organized, so it's nice to always know I have the phone app as a last ditch, if nothing else.
Nate
The Positive Thread...
OFF TOPIC discussions
With the loss of such a positive support beam in the dulcimer community, it reminds me to express my gratitude to y'all. I am very grateful to have found this community of kind, helpful, non-judgmental, encouraging, and inviting folks who I can share the dulcimer with. You have all had a tremendously positive impact on me, and I'm grateful to be able to interface with all you great folks.
I love you all,
God bless all,
Nate
Reasons NOT To Get a Chromatic
Instruments- discuss specific features, luthiers, instrument problems & questions
"It may be true that there are no wrong notes on the dulcimer, but that doesn't mean that all the right ones are there"
Dusty, that deserves a place in the fun sayings about dulcimer chat.
Reasons NOT To Get a Chromatic
Instruments- discuss specific features, luthiers, instrument problems & questions
OverDrive:
Whenever I take up a new instrument, it gives me a fresh perspective on the other instruments I play.
It's funny that you mention this. My experience with chromatic dulcimer is that it enhances my perspective of diatonic dulcimer. The cultural place of chromatic and diatonic dulcimers might be different, but to me, as a self taught dulcimer player, chromatic dulcimer provides me with useful contextual information that I can apply to diatonic.Specifically, hearing the ways that the same chords that I play in diatonic can fit into other keys helps me to think of them with a more open mind.
Nate
Oscar Schmidt OS21C my axe (autoharp)
Adventures with 'other' instruments...
I got the opportunity to play an autoharp once. It belonged to a family friend who would play it and sing when my father was a kid. A couple of the pads had been damaged over time, and it took QUITE a while to tune up, but the ethereal brightness of the sound is unlike any other instrument I've heard. Such a beautiful sound.
Nate
Dulcimer maker unknown
Instruments- discuss specific features, luthiers, instrument problems & questions
Ken Longfield:
Hi, Nate, I'm the other Ken. Here is a link to an NPR segment on the Lego dulcimer made by Peter Alway: https://www.npr.org/2005/02/06/4487244/lego-my-dulcimer As far as I know Peter was the first person to build a mountain dulcimer out of Lego blocks.
Ken
"The dulcimer sings a sweet song.:
Thank you very much "other Ken" xD .That was really neat to listen to. I always enjoy seeing dulcimers made with alternative materials
Dulcimer maker unknown
Instruments- discuss specific features, luthiers, instrument problems & questions
Ken Hulme:
Cardboard dulcimers have been around close to 20 years, I'd guess. They sound remarkably good and are a great inexpensive choice as an entry level dulcimer for folks who aren't sure whether the dulcimer is right for them... The important thing is that the frets are set true, the body material is of secondary consideration. In fact the fretboards can be easily transferred to an 'after-market' wooden body which almost anyone can easily construct. I've played plexiglass and Lego(tm) dulcimers that sound good as well.
Ken, do you have any photos of this lego dulcimer? Or better yet video. You've mentioned it a few times and ive gotten really curious about it. It sounds really interesting.
Nate
String suggestions
Instruments- discuss specific features, luthiers, instrument problems & questions
GreatLakes73:
Hi everyone, looking to buy some strings for my Warren May dulcimer, takes ball end. In his papers that came with the dulcimer he notes .012, .012, .014 and .022 for the string sizes. Most of the “sets” I’m seeing are different gauges or are loop end. I went to d’addario web site to look at just getting individual strings but the options were a bit overwhelming. Any suggestions?
Hello great lakes. I am aware that "Folkcraft" sells a set of ball end dulcimer strings. The gauges are not exactly the same, but very close. Seeing if your local guitar shop sells loose strings is a good idea also. Often times then have a big tub of them, like John says, and can grab out the exact gauges you want.
Nate
Traditional role of the mountain dulcimer.
General mountain dulcimer or music discussions
Wally Venable:
As I have noted before, there is still a culture of "cigar box" instrument makers, many of whom are now making instruments with electric pickups. I suspect that wood from shipping boxes for various imports was used because it was available in usable "thinnesses."
I have built many cigar box guitars, and a few cigar box dulcimers, including a couple very unconventional ones. Nowadays cigar boxes are mostly for 'aesthetics' which is why most of them have pickups that entirely overwhelm and negate the tone of the box. I believe you are right that thin, prefabricated boxes are good for tone and that cigar boxes are, and have always been, very accessible.
It makes sense to me that craftsmen have always been skilled and competent and with capable tools, but I would contend that the ability to build string instruments generally requires access to information. I often take for granted how much information I have access to about dulcimer building, both scientific and anecdotal. For people learning to build instruments without access to information, I assume they used intuition as well as 'trial and error.' and I imagine these contributed to the changes/innovations in zithers that Appalachian Americans made.
Thank you for your insights, Wally.
-Nate
Traditional role of the mountain dulcimer.
General mountain dulcimer or music discussions
Ken Hulme:
Nate said "I assume the original developers of dulcimers were very innovative folks who were applying the concepts of older zithers to the materials they had in the Appalachians. This makes it hard for me to tell the difference between deliberate choices made by the 'masters of old' and choices made purely out of necessity. It's hard for me to imagine that they would have used staple frets if they had access to fretwire."
You have to remember that those "innovative folks...applying the concepts of older zithers...": were not consciously doing anything.
They were random, scattered individuals who heard and/or saw an instrument someone had -- who in turn had seen/heard someone else's instrument... back through time to the zitters which came over in the late 1500s/early 1600s. There probably were no Euro-trained luthiers among the Moravians, the builders to follow were trying to replicate instruments that had come from the old country. -- out of necessity. Staple frets of the early 19th century were the high-tech of the time. prior to that there were wood/bone/ivory inlaid frets or the tied gut frets of Lutes. Mushroom frets weren't invented until the mid 1800s in Europe.
Ken, this perfectly highlights what I mean to convey. That people will ultimately use all sorts of things depending on what is available to them. Perhaps people who understood the parts of a zither on a conceptual level found a lot of different ways to employ these principles with different instrument designs. I still imagine that if you gave top of the line modern building equipment to classical builders of old, that they would be ecstatic to use it. Still, when I see an instrument like a TMB, what I most admire is the cleverness of building a beautiful instrument in such a simple way. Thanks again for the insight.
Nate
The "I have small hands" idea
Instruments- discuss specific features, luthiers, instrument problems & questions
This is a terrific thread and I remember reading it a few years ago when I first started dulcimer. I thought I had small hands when I first started playing, just because I couldn't make chord shapes.
It also didnt help anything that my first dulcimer had a 29" vsl. Still, I played it and got used to big stretches and then I started making dulcimers with smaller VSLs. I was able to make much bigger stretches much more comfortably.
So is the lesson that playing on a hard instrument makes easy ones easier? Or is it that I could have had much less struggle and discomfort by only playing on a smaller dulcimer?
It brings up the question of how much I want to physically challenge myself vs how much I just want to enjoy playing.
Now, I'm convinced I have pretty big hands, but I still prefer a 23" VSL to anything longer. I have a couple years of practice stretching my hands, but there are still really long stretches that I wouldn't want to try on a 29" VSL.
At one point I really wanted to play more challenging music, but I get a lot more enjoyment out of having an easy, comfortable time playing less challenging music. Obviously both are valid. 
I think the big thing is that no one should ever convince themselves that they can't play a longer VSL instrument because of small hands, but making stretches on a shorter VSL instrument is still a lot more comfortable.
Nate
Kora
Adventures with 'other' instruments...
georgia k:
I have a CD of Sona Jobarte playing the Kora. It's really beautiful, but looks incredibly difficult!
Georgia, she is an incredible kora player, thank you for sharing. The kora is an instrument that lends itself to rhythm techniques, so the very high level players do things that most folks would find really daunting, but when using beginner tunings and techniques, it is very easy to get started and make beautiful music.
When I went to the Musical Instrument Museum in Phoenix, AZ they had a small room full of gongs, chimes, large drums and all sorts of easy to "play" instruments like ukuleles and xylophones, which were open to the public to mess around with. I was super excited to see simple koras in there and get to play one. They really are a lot of fun, and very easy to start but quite difficult to master, I'd imagine.
Nate
updated by @nate: 12/23/23 05:26:28PM
What Are You Working On?
General mountain dulcimer or music discussions
Robin, I have gotten value from your posts and am glad to see you back. Merry Christmas to you, as well.
Nate
What Are You Working On?
General mountain dulcimer or music discussions
I have been working on a dulcimer made from goodwill materials only. Metal cans and trays plus wooden cigar boxes for the body, toothpicks frets, and eye bolt tuners. The fingerboard is just a 1/4" thick and 1.5" across strip of poplar. I am out of town but plan on finishing it as soon as I return. The whole thing will end up costing about 5$ and wont require any actual instrument parts. I've been having a lot of fun lately learning ways to make very accessible dulcimers that can be built without many tools and hardware, and with very little knowledge or skill.
Nickel allergy--nylon strings on an octave dulcimer?
Instruments- discuss specific features, luthiers, instrument problems & questions
[quote="shanonmilan"]
[/quote] Does it also make it sound better that you use a specially coated string?
[/quote]
Shanon, each material sounds slightly different, but I don't personally think any sound better than any others.Some are magnetic, which is useful for a dulcimer with electric pickups. Some use fancier metals under the premise that they sound better, but I personally like the different sounds of all string types. Maybe a more refined ear would hear more of a difference.
Nate
Any banjo players out there?
Adventures with 'other' instruments...
My uncle just gave me one of his banjos! It's something I've always wanted to learn.
Traditional role of the mountain dulcimer.
General mountain dulcimer or music discussions
I have no evidence for this, but I suspect that many things we might consider 'traditional' now were done out of necessity at the time. This has always been a bit of a paradox for me. I assume the original developers of dulcimers were very innovative folks who were applying the concepts of older zithers to the materials they had in the Appalachians. This makes it hard for me to tell the difference between deliberate choices made by the 'masters of old' and choices made purely out of necessity. It's hard for me to imagine that they would have used staple frets if they had access to fretwire. Similarly, I have a personal hypothesis that noters were invented to allow a player to keep playing on super old grimy strings.
In both cases, the choices they made then shape what we consider to be the "dulcimer sound" and the "role of the dulcimer." I imagine that over 100 years ago, people may have made themselves all sorts of improvised zithers based on concepts they learned from European instruments. Probably what we consider 'traditional' are the ones that lasted long enough to be documented, but I suspect that with a time machine, we could go back and see all sorts of different 'dulcimers' with different features and roles. Mostly I think it's human nature to evolve and adapt, and I suspect that if you could bring those innovative inventors to the modern day, they would probably be ecstatic to hear how much the instrument has developed and grown.
Traditional role of the mountain dulcimer.
General mountain dulcimer or music discussions
It is interesting to think that at a time when European antecedents were 'traditional,' at one point the dulcimer was probably considered an innovative new thing. I wonder if there were once epinette players who saw new fancy zitters shaped like violins with heart shaped soundholes and looked down on them for not being traditional.
Your real question is too big for me to answer, but I'm sure some folks on here definitely could. If you havent already I recommend joining the Dulcimer History group
https://fotmd.com/ken-longfield/group/38/mountain-dulcimer-history-traditions
and the Dulcimer Ancestors group
https://fotmd.com/strumelia/group/14/dulcimer-ancestors
Strings turned iridescent?
Instruments- discuss specific features, luthiers, instrument problems & questions
Salt Springs:
You can test if it is sulfur based oxidation by doing this, (it works primarily on sterling but you can give it a try...........)
You need.......
a ceramic bowl lined with aluminum foil, shiny side up
a tablespoon of baking soda
a tablespoon of salt and some hot water.
Put just enough water in the bowl to dissolve the baking soda and salt and cover the item you want to clean up.
stick the silver thing in it and see if the sulfur flakes off after a few minutes and moves to the aluminum foil. Dry whatever you stuck in there with a towel and see what you have. I know some jewelry folk put the soda and salt on the item and then pour the water on it.......my sister used to add tiny bit of dish soap on her sterling Native American Jewelry at the shop she had years ago, then buffed it up. She said it takes a bit of practice to get the consistency correct but it works after about 5-15 minutes of soaking as I recall.
Thank you for sharing this neat and informative experiment. You were entirely correct, and the strings eventually fully oxidized to a dull color. Cool while they lasted!
Nate
Maple, and only maple, for a dulcimer?
Instruments- discuss specific features, luthiers, instrument problems & questions
Mary_Adelee:
Is a dulcimer with maple top, sides and back considered to be a good sounding, durable dulcimer?
Different species of maple have different properties, and different trees of the same species will still vary slightly. Two boards from different parts of the same tree can even sound fairly different. I haven't heard any type of wood yet that I felt produced a 'bad sounding dulcimer.' I do enjoy maple a lot for it's durability though, plus it's a beautiful looking wood.
Nate
I've Just Bought a BANJO !!!!
Adventures with 'other' instruments...
Well Ken, I'd suppose that is 6 years of skill developed!
Basic Tuning Question
General mountain dulcimer or music discussions
Brad Richard:
Dusty - Thank you! That works for me. Off to pick up a capo.
Hey Brad, don't forget that dulcimer capos work a bit differently than guitar capos. Plenty of folks make nice dulcimer capos, but you can also use a pencil/chopstick/crochet hook fastened to the fretboard with a piece of string tied around the box of the dulcimer. I personally use a C clamp with a wine bottle cork super glued to the side of it
Nate
6 String Dulcimer Question
Instruments- discuss specific features, luthiers, instrument problems & questions
6 strings provide a fuller "choral" sound. In my opinion, if you are doing a lot of chording, it is much more comfortable with three strings. If you are playing noter drone, more strings often make for a fuller sound. If you are mostly fretting on the melody string, you might consider leaving "courses" (aka 2 strings right next to eachother) for the middle and bass string, or just a "course" for the bass string. I usually play with three strings, and a lot of other folks do as well, but I personally prefer the sound of the extra strings, though it is more difficult. I hope you have a lot of fun exploring this instrument, and there is no harm in removing strings if you prefer to play that way.
Nate
Native American Flutes
Adventures with 'other' instruments...
I have always found the appropriation of dream catchers pretty amusing. Many tribes believe that spider web charms need to be periodically purged through ritual, as they attract and accumulate negative spirits. In Hupa culture, 'dreamcatchers' are associated with a protective spider spirit who is also a moon spirit, and therefore, spiderweb charms are purged through a ritual once every full moon.
I suspect most people who buy them at tchotchke shops are not aware of these sorts of details and are effectively just attracting negative energy to themselves, if you believe in that sort of thing.
Of course, most "dreamcatchers" are just woven mandalas with some feathers and beads glued to the edges and couldn't even be used as a spider web charm. For example, most tribes believe that a spider web charm needs to have a specific number of terminating points along its hoop, typically 12.
I suspect most people who buy them don't actually subscribe to any sort of native american spiritualism, and don't really care one way or the other.