Recent Posts

41

General Discussion / Superb

« Last post by Coleo60 on May 06, 2012, 07:24:50 PM »

Hi! I've been following your weblog for some time now and finally got the bravery to go ahead and give you a shout out from  Austin Tx! Just wanted to mention keep up the good job!

42

Instrument BARS & tuning / Re: Wave in arch while tuning

« Last post by Jim McCarthy on May 02, 2012, 04:54:07 PM »

Not completely unheard of.... but from your description not very likely if all is as it should be. Double check your overtones are in the correct octave.... not an octave too low.

43

Instrument BARS & tuning / Re: Bar Thickness

« Last post by Jim McCarthy on May 02, 2012, 04:50:00 PM »

Hi there...
Well in general you want your bars in the 3/4 to 1 inch thickness range. In that range, thicker is generally better.... but 27mm might be a bit too much... yes. I would reduce it to about 25mm with the planer.... then final sanding etc shouldhave it finish at around 24mm.... perfect!

44

Instrument BARS & tuning / Bar Thickness

« Last post by syisrad on May 01, 2012, 10:08:26 PM »

Hi,

I've begun to make a 4.3 Marimba. I've cut the bars which are Padouk.

The guide recommends 19-25mm thick wood for the bars.

Mine have come in just on 27mm. I was aware of this when cutting the bars but was okay with it at the time. Now especially looking at the higher bars they seem quite on the chunky side and I can't find any images of bars that appear to be that thick.

Will this have a negative effect on the sound? and should I be reducing the thickness?

Thanks heaps

Sy 

45

Instrument BARS & tuning / Wave in arch while tuning

« Last post by syisrad on May 01, 2012, 10:01:19 PM »

Hi guys.

I've started to tune the 1st bar on the 4.3 Marimba I'm making. It's an A2.

I've just got the Fundamental, 1st and 2nd overtones relative to each other and I'm about 11 semitones away from the target.

My question is, currently the middle of the arch at the fundamental is thicker than 1st overtone point forming a wave in physical appearance.

Its symmetrical, sounding as I would expect and I'm confident there's plenty of meat left to reduce it to the final notes.

Should I be concerned? Has anyone had this happen/ is it normal and will even itself out as I get closer? Am I doing something wrong? Should I just not worry and keep going?

Many thanks for reading this.

Cheers

Sy 

46

General Discussion / Hi

« Last post by Sefeinimb on April 27, 2012, 12:11:16 PM »

Hi, I'm new on this forum and I want to say hello. I read a lot of time but today I want to say this is very good site.

47

General Discussion / Hello!

« Last post by anymnBada on December 21, 2011, 01:43:32 AM »

Hello!

48

General Discussion / Re: Marimba bar nodes

« Last post by Jim McCarthy on December 15, 2011, 11:28:15 PM »

mmmm.. that is a little strange, but I guess not unheard of. Sometimes that C2 - especially if it is the first bar we tune - can be a little off in the shape. In general though the bars are close enough that none of them should fall too far outside the "average".

I can't remember the exact cord - and sometimes there is more than one option as discussed in the guide - it is a matter sometimes of trying a few things... 4.8mm cord is a common one I use or 4mm "starter cord". The trick is to find a cord/hole combination that gives room for the bar to vibrate freely - but not so much room that you get a rattle sound - sometimes a bigger diameter cord or smaller diameter hole will help here - or a softer cord exterior - like in the cotton sash cord.

I usually start with something like  4MM HOLE AND A 3 OR 3.8MM cord.
Jim

49

General Discussion / Re: Marimba bar nodes

« Last post by goldnhands on December 15, 2011, 08:14:46 PM »

I have arrived at what I think is the absolute best average for most of my bars, unfortunately my C2 bar is way off and my "average" node line results in the string holes for that bar being too close to the arch and would leave very thin wood if I drilled them there.  I guess I will have to remake that particular bar and try to keep the arch a little shorter.
I purchased 5mm cotton sashcord for my instrument's suspension, is this the same as you used Jim?  How much clearance would you leave in the holes?
I really feel that I am getting somewhere now, picked up a couple of boards of Mahogany for the frame today and looking forward to starting it next week.
Barry

50

General Discussion / Re: Marimba bar nodes

« Last post by Jim McCarthy on December 15, 2011, 12:42:40 AM »

Hi Barry
Yes what you are looking at is really the difference between a custom job and a more commercial mass production approach. Most commercial maufacturers don't want to adjust their frame dimensions to suit a particular set of bars - so they average even further. The suspension system used on marimbas is actually quite forgiving so you will find it sounds good even with this seeming innacuracy for some of the bars. What I try to achieve though if you are individually customizing each instrument... is the BEST result you can. so make the frame dimensions... ie strut positions match as close as possible to the particular set of bars. Also of course the issue of the preliminary salt testing. I am not sure if this is normally done - I suspect not. I never heard of it before I had the idea to do it myself.... The idea is to determine the tendency for angle of the nodes on a bar before tuning to make that angle more accurately match the angle the strings will need to take anyway depending on whether they are black notes or white notes. You do the initial test then arch the bar on the appropriate side. All this process is just refinement designed to get the strings as close to actually on the nodes as possible for as many bars as possible.