Skin mounting: height, angle, loop distance

[taikonoatama]

Skin mounting: height, angle, loop distance

I know some of these things have been talked about here, but I'd like to open this topic anew with all three of these parameters in one place because they are so connected. Obviously other things factor in here in relation to the sound of a drum, but let's hit these here.

Skin mounting height (vertical distance between the top of the crown and the plane across the top of the head)
Does it affect sound and if so in what way?

My take:
Outside of sound, obviously a skin/crown mounted too high will hurt your hands, but the minimum height will vary from player to player, depending on technique. But we're talking more just about the sound here.

One way to think about the differences in sound is to think of extremes. Let's compare what we might hear if we were to mount the skin at one extremity of the spectrum, with the crown flush with the plane of the head, vs. having it a foot (30 cm) down the shell. My thinking is that in the latter case, all that extra skin is going to vibrate and in turn vibrate the shell, and also send vibrations back up to the main head, and that these side-skin- generated vibrations will clash with the those coming from the head and cause overrings. In the former case, with next to no side skin, this would not be an issue. But that's extremes (and I could be way off base, I realize), so how much would this figure into crowns/skins mounted say, 1/4" (62 mm) vs. 1" (2.5 cm). I do not know.

Angle of skin coming down off bearing edge
On some drums (like Skin on Skins with traditional crowns, and King Conga fiberglass congas), the crown is very tight to the shell, and so the skin as it comes over the bearing edge goes straight down the outside of the shell, actually staying in contact with the shell for a good ways, until just above the flesh hoop level. On the other extreme are a lot of drums with comfort curve crowns. The comfort curve, by its nature, forces the skin to come off the bearing edge in a much more flared out way. Once again, imagine extremes. Clearly the tight-to-the-shell style would not vibrate much on its own, whereas the comfort curve version would. Even at normal mounting distances, I wonder if the comfort curve angle and the extra skin that system hangs out there to vibrate leads to problematic overrings. I can't imagine this being an issue with the tight-to-the-shell style, though I suppose there could also be an effect on wood resonance at a certain point. In defense of the tight-to-the-shell style, my SoS's have a nice long resonant open tones without nasty overrings, and they don't seem choked off at all. Still, I don't know for sure.

Distance between crown loops
Probably not such a big deal with most drums having 5 or 6 lugs. You can see how having too great a distance between the lugs could be an issue, though, when you consider what a 2-lug drum would sound like. There's no way the skin that's near a non-lugged part of the crown would be as tight as that near one of the two lugs. It would be impossible to get it tuned right. More lugs balance this, of course, as do v-shaped crown loops that spread the tension across the crown rim. This parameter has largely been taken care of for some time.

Anyway, just some thoughts. Calling all acoustical engineers ...

James



Edited By taikonoatama on 1204674299

[Chupacabra]

I'm glad this subject has been raised because my tumba is giving me some grief with some excess ringing. Actually, it sounds more like feedback...
Visually, as far as I know, everything looks A.O.K. I took various measurements from other similar drums that I like the sound of and brought it as close as I could to those dimensions as I gradually tightened and tuned it as the hide dried during the initial assembly. Oh!... I should mention that I made my congas from shells, hardware and hide that I bought elsewhere. After about 3 or 4 days, once I thought the hide was dry enough, I started to tune it. The more I tuned it the louder the ring got. So I figured that maybe it just needs to be played; so play it I do, but it just sounds nasty!

The ironic part is the fact that the quinto and conga both sound really nice but the crown sits way too high on the quinto and is a bit off-kilter on the conga!

I am starting to think I might need to start from scratch and do it over again until I get it right. If I can get some other ideas it might save me from all that.

[blango]

My take on this..

If a skin is in more contact with the shell, it will have more of a punchy sound. but it only goes so far... if you stretch a skin all the way down the side of the drum, making it very hard to tune, it will still sound decent. In other words, i think there is a point where the shell lends as much as it can, and more contact with the skin is gratuitous.

As far as the lugs, for me, more lugs, less chance to bend the crown, and crack the shell.

Tony

[Isaac]

If you take a look at the best handmade congas and bongos,
you'll see that the skins are not pulled down very far. This
is true for Skin on Skin, Junior, JCR, and Matthew Smith, Isla.
Perhaps this is one of the key factors in their good sound?..
besides their better wood. Too much pull down wil choke the
skin's vibrations. There's probably a sweet spot for each
shell and it's skin...but don't expect that by pulling it
down far in advance you'll acheive it.

A lot of players are also justifiably concerned about hurting their hands if
a rim is too high...so instead they search for either a lower mounted
skin, or the ubiquitous ( and cheaper ) comfort rims....all
of which compromise the pure best sound that can possibly be acheived.

A rim that seems high to start will eventually move down over time,
as the skin is played and broken in. One must be both patient
while this process takes place and in the that time practice improving
your technique. ( so hitting a rim should never occur )

If you start with the skin pulled way down, where do you go from there?
You've just shortened in advance, the life span of your drum head.
The old drums ( with way pulled down skins) that look like that got that way over many years.
It's not like buying "pre -faded" jeans...you have to put in the time.

Comfort Rims and that are usually too wide, that leave a wide angled space
are also a major cause of ringing overtones. That space acts as an echo/sound chamber
-in other words, it becomes a 2nd instrument competing with the sounds
you really want. If you were to accidently wack your wrist on a metal
comfort rim - you'd still be risking serious nerve damage...so where is the
comfort in that? It makes no sense.

We had this thread on rims a few weeks ago..and "BongosNotBombs" summed it
up very well.

Anyway, the most important thing is to keep practicing and staying
musical until we merit better instruments... Ultimately
we are the "Instruments".

~ ISAAC
TRADICION / JCR PERCUSSION CO.

[Diceman]

Ultimately we are the "Instruments".--Well said Isaac.

Is there any way of damping the overtones on the 'flared' part of the skin, packing etc?

suave