How to place air vents on my 3 ply African Mahogany Shells

Hi!

I just got a set of 3 Ply African Mahogany shells. They are 6mm thick, with 6mm 3 ply maple re-rings (rings are 22 mm wide). The sizes are 20"x14", 12"x7.5" and 14"x12.5". I centered the Sligerland Stage Band replica lugs, mounted the hardware and heads on the shells but the toms really choke a lot.

So I'm convinced I need to vent them. I saw that Guru Performance Padauk shells were vented just bellow the batter side rim. I imagine that this might be a good idea to vent my drums. What do you think about it?

I though about 3 or 4 3 mm holes spaced on the perimeter of the batter side of all drums.

Any thoughts on this?

Thanks

What's your mounting hardware? All other things being equal, 'choking' is much more likely to be due to your mounting setup and resonance grounding than it is anything to do with vents.

The only choking that would occur solely due to the lack of active airflow (unvented) would be if you're absolutely hammering the drums and the pressurisation of the sealed air column is overextending the heads. Venting on drums is mostly required for passive airflow and maintaining tuning stability (in an unvented drum you get imbalances of air temperature and humidity causing pressure changes which causes tuning changes. The most common example of this would be an unvented drum played during soundcheck in a cold dry room, and the tuning ends up completely different two hours later with the heat and sweat of a room full of people and a kit that's been left under stage lights).

Those are also hellish thick drums at the edges due to the rerings - what bearing edge profile have you put on them?

Anyway, I wouldn't dream of owning any unvented drums because of the practicalities, but all you need is one vent - AND you can 'bung' the vent after tuning if you really want the subtle sound and feel change that unvented drums produce. I believe you'd need to be under laboratory conditions to prove that variations of placement on the shell would yield even minute variations of sound, so just put it where it looks good to you.

Try posting some pictures of the kit and a shot of the bearing edges. Then we'll all wait for Andy (Keep it Simple) to show up and teach us all something about drum construction. The pictures of the kit are just to keep the rest of us entertained while we wait for Andy.

For the 12" tom I had a snare stand, but I switched to a Pearl ISS.

For the 14" floor tom I'm using Gibraltar SC-GRUC. R-Class Universal Hoop Clamp to and then the floor tom legs attached.

I would buy the air vents first to determine the size of holes you are going to drill. and not vice-versa.One or two holes would sufficient. Maybe on the sides opposite the badges

Funkyvasc said:

For the 12" tom I had a snare stand, but I switched to a Pearl ISS.

For the 14" floor tom I'm using Gibraltar SC-GRUC. R-Class Universal Hoop Clamp to and then the floor tom legs attached.

Click to expand...

Pearl ISS are notorious for choking the drums - clamped to the batter hoop and then grounded straight into the floor via the mount. What did it sound like in the snare stand - crucially WITHOUT the basket being clamped close, but just tight enough to hold it in place? Try mounting like this:

http://www.pearldrummersforum.com/attachment.php?attachmentid=387551&stc=1&d=1285307387

Likewise with the floor tom - the R-Class clamps tightly grab the hoop, so unless you're using sprung floor tom legs (?) you're also grounding the resonance out of the drum straight into the ground.

flurbs said:

Pearl ISS are notorious for choking the drums - clamped to the batter hoop and then grounded straight into the floor via the mount. What did it sound like in the snare stand - crucially WITHOUT the basket being clamped close, but just tight enough to hold it in place? Try mounting like this:

http://www.pearldrummersforum.com/attachment.php?attachmentid=387551&stc=1&d=1285307387

Likewise with the floor tom - the R-Class clamps tightly grab the hoop, so unless you're using sprung floor tom legs (?) you're also grounding the resonance out of the drum straight into the ground.

Click to expand...

Well thanks Flurbs!

I'm gonna give it a try... mounting it on a snare stand like you said, and Im gonna use the Pearl Master series kind of floor tom legs. And then see how it sounds like. As a matter fact, holding the 12" tom loosely with one hand and hitting it with the drum stick it sounded way different than placing it on any kind of stand.

flurbs said:

I wouldn't dream of owning any unvented drums because of the practicalities

Click to expand...

There are no "practicalities" if the drum is designed correctly. We currently produce all of our drums unvented, & there are zero atmospheric/tuning retention issues or choking problems. We've designed out all potential issues that were present in unvented drums around years ago, but capitalise on the benefits. Unfortunately, I'm not at liberty to say how we've done that on a public forum.

Funkyvasc said:

So I'm convinced I need to vent them. I saw that Guru Performance Padauk shells were vented just bellow the batter side rim. I imagine that this might be a good idea to vent my drums. What do you think about it?

Click to expand...

You may well benefit from venting, it's difficult to advise you without actually working with your drums, but I really doubt venting is the primary issue here.

As a point of clarification, we did use edge venting on the first series Padauk Origin drums, but have since stopped doing that. The primary reason for edge venting on that design was much more to do with interruption of standing waves to assist in control of overtones specific to a padauk shell. We've since designed around that with the series 2 segmented Origin shells.

I sternly suspect your issue is not choking at high dynamic or tuning pitch, but a combination of bearing edges, grounding resonance issues, & tuning. Those are always your first port of call.

Ok, Thank you very much for your reply Andy!

Im gonna further investigate this matter, and try to understand whats going on.

Regarding the vent holes, I'm just a bit concerned to drill them on the re-ring, but I guess 3 mm holes wont be a problem, I hope.

On toms I feel that the heads have an excess of medium high overtones, they shouldnt be there that much, given the specs of the shells. When I play the toms at higher dynamics these overtones seem to be higher and overcome the low end and resonance of the heads. I just tryed a medium high tuning range yet.

I dont want the drums to resonate the whole day long, I like a slightly muted tone, and I guess that should be provided by the fully rounded bearing edge.

Would placing a 9mm hole in the center of the shell make a noticeable difference when compared to placing 3 3 mm holes around the edge? I mean theoretically. Given the caracteristics of my shells.

Thanks,

Funkyvasc said:

Ok, Thank you very much for your reply Andy!

Im gonna further investigate this matter, and try to understand whats going on.

Regarding the vent holes, I'm just a bit concerned to drill them on the re-ring, but I guess 3 mm holes wont be a problem, I hope.

On toms I feel that the heads have an excess of medium high overtones, they shouldnt be there that much, given the specs of the shells. When I play the toms at higher dynamics these overtones seem to be higher and overcome the low end and resonance of the heads. I just tryed a medium high tuning range yet.

I dont want the drums to resonate the whole day long, I like a slightly muted tone, and I guess that should be provided by the fully rounded bearing edge.

Would placing a 9mm hole in the center of the shell make a noticeable difference when compared to placing 3 3 mm holes around the edge? I mean theoretically. Given the caracteristics of my shells.

Thanks,

Click to expand...

I wouldn't even go into venting until you've exhausted all other options. If your shells aren't currently resonating to their full potential (& that has absolutely nothing to do with head sustain), then overtones will always dominate over the fundamental, & that affect typically has a linear relationship with dynamic.

Practical measures: Are you getting the same dominance of higher overtones when you hit the drum hard held by the rim with your hand? If so, then it's either a bearing edge/tuning/mounting issue and/or a construction issue (possibly including venting). If you're not getting the same higher overtone dominance then it's a bearing edge/tuning/mounting issue - the most likely elements being tuning/mounting.

As a side note, 3 x 3mm holes do not have the same venting capacity as 1 x 9mm hole. Drilling 3mm diameter holes in the rering has no structural implications.

keep it simple said:

I wouldn't even go into venting until you've exhausted all other options. If your shells aren't currently resonating to their full potential (& that has absolutely nothing to do with head sustain), then overtones will always dominate over the fundamental, & that affect typically has a linear relationship with dynamic.

Practical measures: Are you getting the same dominance of higher overtones when you hit the drum hard held by the rim with your hand? If so, then it's either a bearing edge/tuning/mounting issue and/or a construction issue (possibly including venting). If you're not getting the same higher overtone dominance then it's a bearing edge/tuning/mounting issue - the most likely elements being tuning/mounting.

As a side note, 3 x 3mm holes do not have the same venting capacity as 1 x 9mm hole. Drilling 3mm diameter holes in the rering has no structural implications.

Click to expand...

When I hit the drum holding it with my hand, the fundamental tone is way much more pronounced, the overtones are highly reduced. I placed a tiny piece of 1mm thick rubber around each lug hole in a way that the wood wont get damaged by the pressure of the lugs against it.

What if I would have 5x (because the 12" have 5 tuning rods on each side) 3mm holes around the edges as opposed to 1x 9 mm? Would that raise the venting capacity? My thought to vent around the edge is to reduce the excess of overtones produced by the head. I imagine that placing several small holes near the head would have a more pronounced effect on reducing overtones than placing a single bigger hole in the center of the drum.

FWIW, I'd remove the rubber gaskets from your shells. Don't worry about the lug leaving an impression on the finish. You can't see it anyway, and it's better for tone without lug gaskets. I remove them from all my drums and I can hear a definite difference for the better.

Another suggestion is to get real RIMS mounts and try them before drilling your shell. They outperform the Pearl ISS mounts.

I would try some Evans Genera HD drum heads. They are designed to reduce overtones.
They have tiny holes in the drum head. This might give you a similar effect to venting the drum shell.


.

Get the Evans Genera head single ply.

Try it.
If it sounds too dampened to you, then carefully cut off the dampening ring. Now you have a vented drum head.

Try one head only on the reso side.
try one head only on the batter side
Try two heads, reso and batter.

This is a picture of the double ply Genera:





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Funkyvasc said:

When I hit the drum holding it with my hand, the fundamental tone is way much more pronounced, the overtones are highly reduced.

Click to expand...

You've pretty much answered your own question. Venting is unlikely to be your issue, or if it is, it's a minor contributing factor. To repeat, forget about venting & concentrate on the other much more likely issues that I outlined in my previous post.

larryace said:

FWIW, I'd remove the rubber gaskets from your shells.

Click to expand...

Agreed. Rubber gaskets, no matter how much marketing spin is used to justify them, are mostly for manufacturing convenience. The moment the lug fixing is tightened, & the rubber compressed, any potential isolation benefit is lost. Apart from which, drums resonate as a whole, not as component parts. Rubber is a dead dampening mass.

Hollywood Jim said:

Get the Evans Genera head single ply.

Click to expand...

If you really must scratch your venting itch, this isn't a bad idea. Although not an exact replication of shell edge venting, it's near enough. That said, your quest should be to get your drums working well with basic heads. With any drum, outside of special occasion recording requirements bass drums, having to fit pre muffled heads is merely masking an instrument deficiency or a lack of tuning ability.

I must say that I have Aquarian modern vintage top and texture coated bottom for the toms which give me a pretty open tone. If I put double ply heads, the sound should be more controlled.

I gave it a shot on shell edge venting on the 12" tom, et voilà, I got the overtones under control, they're not totally missing, but the drumhead breathes more, and the fundamental tone is more pronounced. However when I tune it up those overtones become more present again. I dont like to use moongel, but a tiny piece is very efficient in making the fundamental of the tom a lilttle more audible, without choking it too much.

As for the rubber pieces, I just put a tiny very thin piece at the very edge of each lug. Its not a full gasket. I dont think it might affect the sound that much, and saves the soft wood from being damaged. Furthermore I need to raise the lugs in order to avoid splay effect on the tension rods, specially on the bass drum.




http://www.worldmaxusa.com/cart_product.cfm/prod_id/73505/bk/1/cat/12728

I think you need 1 ply reso heads and not coated. They will reduce the resonance a little too much. The are made or batter heads I think

Funkyvasc said:

I gave it a shot on shell edge venting on the 12" tom, et voilà, I got the overtones under control, they're not totally missing, but the drumhead breathes more, and the fundamental tone is more pronounced. However when I tune it up those overtones become more present again.

Click to expand...

& this is exactly why I strongly advised you don't move to edge venting until the issue is fully understood. You've treated some of the symptoms, not the primary cause.

I know edge venting to be a powerful drum design tool, but it's also a blunt instrument if used incorrectly. It's application is little understood, & has potential downsides as well as potential benefits.

When I hit the drum holding it with my hand, the fundamental tone is way much more pronounced, the overtones are highly reduced. I placed a tiny piece of 1mm thick rubber around each lug hole in a way that the wood wont get damaged by the pressure of the lugs against it.

Click to expand...

I agree its a 'grounding' issue, which all drums are susceptible to. RIMS mounts, the new(er) BOOTY SHAKERS are possible avenues to more resonance.


There's a specific unspecified formulae to drum building, it has to do with the ratio between hardware to shell weight, get this on either side of optimal and the drums aren't going to be as resonant.

Manufactures/builders are usually not even aware of said formulae and are at best stumbling upon a good ratio, the most successful builders come closest to that optimal ratio. A few builders actually know of the concept and are experimenting with and applying their findings to their instruments. Don't expect a white paper to be published tho.


My idea of a way around the grounding issue with bass drum mounted toms is a well designed set of shock absorbing bass drum spurs. When people think about it they might immediately rationalize an error in not having the bass drum concretely stable. Drummers have been conditioned to believe bass drum spurs need to be solid, when in fact if they had some cushioning ability they would actually isolate the kit from coupling to the ground (grounding). I also believe such spurs would improve the playing feel of the bass drum.

RIMS mounts have a de-coupling effect on toms, but the point of grounding isolation for the whole kit is at the bass drum spurs i.e. where the drum(s) meet the ground. Isolation FT feet prove a good example, the effects would be the same on bass drum spurs, and extend to not just to the bass drum, but also everything mounted to it.

keep it simple said:

& this is exactly why I strongly advised you don't move to edge venting until the issue is fully understood. You've treated some of the symptoms, not the primary cause.

I know edge venting to be a powerful drum design tool, but it's also a blunt instrument if used incorrectly. It's application is little understood, & has potential downsides as well as potential benefits.

Click to expand...

Well I dont have the means nor the knowledge to fully understand the issue, in order to treat the primary cause. If I did a mistake by drilling the holes then I learnt it the hardest way I guess... But the bottom line is: for the tuning range I like to use most of the time, this drum is working fine so far.

I checked the bearing edges on a totally flat surface, and they were fine, I tried different tunings, from very high to very low, always carefully checking each tuning rod individually, I tried the same pitches on both heads, I tried different pitches... I noticed one very slight "bump on the exterior perimeter of the shell that might be the source of the issue. I know that Old Ludwigs had 1 bump on the outside of the shell, and some people say that this is part of the characteristic slightly muted sound, The shells were not 100% round.

Ok, so my shells are not 100% perfect, but I have to find a way to get the best out of them with the tools and little knowledge I have. The edge venting tool had this 12" tom sounding much better. I have no idea about the theory behind this, I only had the feeling that it might work for me. It takes a lot of A-B testing, a lot of trial and error, to fully understand it I guess... I would like to, but I cant afford a set of top quality drums, so meanwhile, I work with what I have and I try to learn as much as I can about drum design, not necessarilly to become a drum builder, but to make smart choices in the future regarding the sound I'm looking for.