cup tuning basics.

[thelostMIDrange]

This is a personal journal in exploring the 'tuning' of wood cups for a magnum v4 driver. totally random and unorganized, for educational purposes only.
 
mission statement: do the mag justice by building a cup to maximize musicality, naturalness and expression of emotion in music. Specifically the development of a wood cup that has little to no 'wood color' but retains wood's natural affect on sound,
 
Ideal headphone would have a variation of the grado style presentation with more natural e/q and smoother, with more extended and better defined low end and a nicer 'atmosphere' rather than a rip your face off sound or just an 'in the band' sound. I want to be the band ! and feel what they feel, not watch. music is not a spectator sport. it is part participitory, 'be the band',  but mostly for me, it is a vehicle to be sent out from worldly cares. It is magical and agree with aldous huxley when he says, that which comes closest to expressing the inexpressible, it music.
 
the underlying assumption is that the cup that holds the driver is a complex and subtle little carrier and needs to be finely tuned to a particular driver in order to achieve anything approaching musical and/or reference qualtiy headphones that do not fatigue over long term listening sessions.
 
And cup tuning is the art of maximizing synergy and potential of a particular wood cup (in this case) and driver.
 
The basic method is simple. Listen to a raw wood without finish in several different cup geometry's. Get acquainted with its vibe, note it's strong and weak points, as well as those of each cup geometry (particularly length of cup, mass and wal thickness)
 
Once you have chosen your favorite raw wood cup sound, you can make assumptions about why you like that particular cup (length, shape, thickness etc) or you can just proceed to the next step which is applying a finish. And know that cup tuners that have come before you have already established that the finish plays a big role in final sound.....
 
So the goal of finishing is to retain as much of the raw wood sounds' nicer qualites while simultaneously negating as many of the raw woods sound 'problems'......This is how to judge the success of your finish treatment. I have found that the finish generally does take a quality of two down with it and does fix a quality or two of it's problems. I've never succeeded in never losing a quality and negating all the negatives with finish. So it's an imperfect science, but it's still a powerful tool in the cup tuners bag o' tricks and shouldn't be left unused. A wood cup needs all the help it can get to sound musical, natural, and free of wood color.
 
What wood should the cup makers of the future utilize. Stick to hardwoods. Stick to diffuse porous woods (most hardwoods are) and not ring porous woods
 
pic showing ring porous (left) and diffuse porous (right)

 
To further increase your chances or musical cups, concentrate on those diffuse porous woods with medium to large pores. Larger the better. This is what seems to give breath to sound. Small to small medium pore woods tend to sound hard and/or strident. Avoid hardwoods that are too light and soft (low density) as they tend to sound too airy and can lack punch and impact (32 or less)
 
those that are most likely to yield musical cups ime:
limba, avodire, mango, iroko, zebrawood. I have only heard 2 of these. The other wood that theoretically should yield good results if the above criteria are valid is east indian rosewood as it is diffuse porous with large pores, but I didn't have luck with it. I admit I only tried it in one cup length, and I have since found that length of cup is critical, so perhaps in the right length I could have gotten that rosewood to work. Just goes to show how one of these major variables that is out of line can ruin the whole synergy and tuning of cup. Either that or the rosewwood was too dense, which is another suspicion of mine that such woods are less likely to yield natural sounding cups. This is an immature science however.........
 
Here is a compilation list of various woods (all diffuse porous unless noted)
 
 
Species                Density lbs/ft  
 
softwoods:
Cedar, Western Red 23
Sequoia Redwood 26
Spruce, Sitka 27
Port Orford Cedar  30
 
 
hardwoods medium density:
Mahogany, honduran  34 large pores
Bigleaf Maple 34
Walnut  36  semi ring porous small pores
Black Limba 37 medium to large pores
Avodire 38 medium pores
Teak 42 semi ring porous
Koa 41 small pores
Mango 43 medium pores
Acacia 42
Iroko 42 large pores
 
hardwoods very dense/hard:
Mahogany,african 43
Maple, hard 45 small pores
Rosewood Brazilian  53 small pores
zebrawood 54 medium pores
Pau Ferro 55 small pores
Wenge 57 large pores
East Indian Rosewood 57 large pores
Bubinga 58 medium pores
Cocobolo 67 small to medium pores
Ebony, Macassar  69 small pores
Ebony,gaboon 69 small pores
kingwood 74 small pores
Bloodwood 78 small pores
African Blackwood 78 small pores
 
 
 
cup tuning is serious fun !
sense of humor and love of music only requirements beyond this point.....enter here if you dare.....

 

[thelostMIDrange]

installment #117
 
limba
1.25" overall length
1 3/8" port
simple bead end detail
standard truoil treatment
 
only variable is inner wall treatment............one wetsanded but didn't succeed well, raw wood mostly, other left oil finish as is
 
oiled: hotter, similar to platicized grados.
bass almost totally unaffected
starts affecting at low mids
much more treble energy
 
 
wetsanded:
lost too much treble in the deal
 
 
note to self: try again with a true wetsanded cup
 
 
 

 

[thelostMIDrange]

installment #118
 
limba
1.25" overall length
1 3/8" port
simple bead end detail
standard truoil treatment
 
only variable is inner wall treatment............successful wetsand vs standard oil finish
 
oiled:
darker
murky bass
more treble energy-not of high quality\
strident vocal
 
 
wetsanded:
nice hi hat
more natural snare
nicer bass definition- nice and weight'y
natural vocal
 
 
 

 

[drtturnip]

I suppose those little wood fibers would suck up some energy.

 

[thelostMIDrange]

RAW hond mahog vs tiger maple
 
dug out this . tige rmaple, was one of my favorites back when the drivers were breaking in but felt it was a little too airy and light. With burned in magnum, the match is as my pappy used to say, 'sumthin else' after a few hundred hours, the magum 'dropped' and is now better suited for this wood. limba less so after burn in btw
 
 mahogany just sounds so workmanlike. it gets the job done, but doesn't set my heart aflutter. still an odd honky boxy qualtiy to the mids. Thetiger maple   in contrast, sounds like a breath of fresh air. don't recall ever hearing bass so articulate. lots of air throughout the mids. very spacious. vocals are supernatural, realistic, balanced. Only real issue is a touch of splash in the trebles and a very slight lack of fullness, which might very well get taken care of with finish. it's right in the finish's wheelhouse of things it tends to deal with. Will be spending time with this maple. Bass is perfect. amazing the difference. These are very similar woods and yet ENTIRELY different........totally different vibes.

 

[thelostMIDrange]

RAW limba vs tiger maple (same as above) v4 300 hours
 
limbas low end is not defined, biggest difference here. santos lows are not as full but far more defined. very musical.
maple has an echo'y quality that is part enjoyable, part odd. Very well could be taken care of with finish.
limba is a full sound, sometimes too much so depending on the material.
limba has rich midrange. maple more sparse
maple has a special thing going on in the upper end. super enjoyable. natural, ride cymbals stand out on a pedastal
vocal expression hard to beat with maple. very close emotional connection. vocal vibrato seems to linger . very nice
 
 
 
 
 
 

 

[thelostMIDrange]

 
raw limba vs finished limba
 
hearing what the finish is doing here to the treble makes me very excited about the possibilites of that tiger maple. If it calms down the same way, might be super sweet. the finish tames the splash and gives fullness to the mids, about the only two things lacking in the santos......I believe the finish on this limba is tru oil but not certain....so will try it and linseed on the santos with high hopes. May have to change application and will take some time, but worth the effort to see if santos can really be woods' version of aluminum. Seems to have the best of both materials in it's nature. Will take the right finish to bring them out without ruining it's magical raw wood sounds......it's easy to ruin good things in raw wood with finish. This is the art of cup tuning - improving the faults of the raw wood sound while not losing raw wood's strengths...
 
finish changes the entire character of the sound. many times more refined. general e/q is almost the same for each but just about everything else sounds different...
don't feel i did limba sservice with this finish.....there are nice qualites in the raw wood sound missing in finished. I murdered the bass. don't know how though
 
 
 
 

 

[thelostMIDrange]

 
raw tiger maple (same as above) one chamber 1.25" other 1.75". everything else identical.
 
revelation
 
longer cup has no redeeming value in comparison, shorter cup does everything better, even low end
 

 

[thelostMIDrange]

one cup has the oil finish unsanded on the inner chamber walls, the other has same oil finish but wet sanded to a slurry and wiped away, leaving a semi-bare wood oil penetrated surface. Oil is hardened underneath.....I've done this to all my recent oiled cups, not just this little a/b. and spent quite a bit of time enjoying the results. I find this little tip really helps keep the upper mids, especially snare drums from sounding artificial. It gives a nice balance between refining the upper mids while keeping them quite musical and neutral. Generally I've found the inner finish treatment affects the upper mids the most..

 

[thelostMIDrange]

interesting thing about mahog and limba.......when they are used to make a guitar, they end up like this:
 
the mahog is darker sounding and low mid centered, the limba is brighter, sharper and high mid centered.......
 
when used for headphones, the opposite happens, the limba is darker sounding and low mid centered the mahog is brighter and high mid centered......
 
what does this tell us about resonance in the two scenarios? and/or the affect of the finish treatment on resonance?
 
 
 
some more details on the inner surface, 'foundMIDmod' anyone who can hold back the little devil on your shoulder telling you this stuff is voodoo and a total waste of time will reap the benefits and anyone who can't, will not. life is not often fair, but this seems to me an exception.
 
I oiled these yesterday. I usually do the wetsand 'foundMIDmod' many days or weeks after the cups have dried.This time i wanted to rush and do it so I can compare oils, since these were done with danish again. I have been using tru-oil for the last month.....side point, will be doing alot more comparing of 3 oils (danish, tru, linseed) soon..........back to story, and come to find that the mod won't work unless the oil has time to fully cure. so at this point i'm thinking a week or so. What happens when you don't wait is all the oil just lifts off and bare wood is left. It looks different and feels different compared to when you do it right (and does not sound nearly as good as mentioned before).......see bottom of post for how it should look and feel if done right

 
 
so I need to take the time and clairfy some details on this mod. More for my own clarification but might as well post it too............ god is in the details here.
 
let's assume one is doing a full finish of the cups themselves from the beginning, apply your 3 or more coats of oil in a particular manner - dip entire cup into bath, pull out within 10 secs, wipe off excess in 15 mintues. wait 2 days, wipe on with cotton t shirt the 2nd and 3rd coats which can be right on the heels of each other(whatever the instructions tell you for that oil (30 mins for example) since we are only waiting for the first coat to harden and stop further coats from penetrating...........now back to mod, after you have waited a week or at least several days if you can't wait, for the full cure, do the wet sanding but keep these things in mind:
 

this process should take 60 seconds or less/cup..................you can see the 'slurry' here. 150 -220 grit paper. very lightly dampen the paper in a few drops of water, andthen just circle it around the cup lightly 2 or 3 times. we are not trying to sand anything or remove the oil necessarily. we want to just loosen it up, suspend it in the water (slurry) and after the slurry forms, take a t shirt and circle the slurry around, spreading it on the wall.....some will come off on the tshirt and that's good. we also want to get rid of the top film of oil. but do not 'dab' at the slurry and try to pick it out,,,,,we want to spread it like butter around the inner wall. again this is just a full rotation or 2 with the t shirt. do not scour anything during this process......this process should take no more than a minute really.............VERY GENTLE.........wait a few days for it to dry, listen and if needed (if snare drums sound artificial is a great constant to check with), go back and repeat the process: a couple circles with wet sandpaper, and quickly (before it dries) a couple circles with a cotton shirt...................that's it. if you've done it right, the feel will be much like a smooth rock or piece of marble; hard and smooth.....if you feel a rough or bare wood surface something went wrong and would have to start over by oiling, wating for cure, try the mod again, probably more gently with a greater appreciation of what you are tying to do..........Also, right after you do this mod, the wood will still be wet and therefore dark in color, much like the oil. so it will look like nothing has been done....it takes time for the thing to dry and the fruits of your labour to reveal themselves and the result should look alot like bare wood, but different, with a hue of something else in the background (which is the butter spread and hardened oil slurry)...... Again, I know you may be saying to yourself (the little devil is saying it to you) this is a waste of my time, i could be watching american idol.....and you will not reap the benefits if you give in to that devil, proving that the world does make sense sometimes and there is divine justice.

 

[thelostMIDrange]

 
 
painted hond mahog outside only vs raw hond mahog v4 300 hours
 

 
Paint on the outside only, is certainly no liability and possibly an asset. The difference between these two is subtle, but If forced to choose one, I would pick the painted set. In fact I will finish painting these and make a set out of them with standard oil on inside- even didn't get all the paint off and still they sound quite nice. So paint on inside. Big no no. outside, I don't see why not .

 

[thelostMIDrange]

identical limba cups except inside finish:
one has wetsanded gunstock oil with no top coat the other has gunstock oil inner with inner topcoat of paste wax v4 300 hours the waxed is a little artificially 'smooth' sounding. Things are a little smeared together and snare drums are artifically 'fat' sounding. I was already familiar with the affect of wax on the inside because I made 2 sets with this formula a while back, when I placed less importance on the inside surface. I was waxing the outside, and said, why not wax the inside too. It's not that the wax on inside sets were terrible sounding, just a little artifical and smeared. It became irritating after listening for longer time periods when all the songs had a carry-over of some quality. That's when I knew something is up and traced it back to the wax. I don't recognize any ill affects from wax on the outside however and have made many sets with it.
fec

 

[thelostMIDrange]

 
Limba raw vs Limba w/ 3 coats gunstock oil v4 300 hours
 
The finish is the only way to refine the midrange and upper end. I don't think I prefer the raw wood sounds in any wood vs a finished one. The trick and difficulty is how to choose and apply the finish so that the wood sound is enahanced not ruined. Raw woods generally sound good, but lack control in the way the mids and trebles decay. Raw sounds are more splashy and un-civilized. The decay is more ragged. The finish gives body to the upper end. Raw wood just doesn't sound 'finished' or right in some way. Cup tuning is how to choose the wood and finish for a particular driver. It has to be deliberate. To not fine tune methodically results in a total crapshoot as to whether it will sound musical and even........... And these two woods are actually quite similar in properties and yet they are quite different sounding. Those exotics are way different in their properties. We are at like page one of the story of cup tuning................In a way, I feel wood is a great choice of material for cups but also, not ideal. It takes the finish to really bring it up to the level the magnum driver deserves. Wood is too organic sounding raw and needs finish to refine it. Metal is not organic enough raw and needs a finish to give it soul. I think we'd have better luck and control with the former than the latter. It's hard to give soul to metals but possible to give grace to wood imo
d
 
 
 
 

 

[thelostMIDrange]

perhaps an extreme example,but for fun, I made these mahogany in paint..... more proof that finishes matter.....these don't sound good. Next is to remove any paint from inside surface and recheck. Should sound similar to oiled mahogany I suspect. ......

 

[thelostMIDrange]

"I suppose those little wood fibers would suck up some energy."
 
very generally, I can say raw wood sounds very unrefined. meaning, dry, poor instrument truness. mids tend to be chewy and highs tend to be washed sounding. Raw woods can still be enjoyed. I have listened to some for hours but I would never think of them as a final solution for a sound chamber. It takes the right finish to make them musical and natural sounding. So yes the raw wood fibres certainly do absorb lots of energy.