Tone-hole ‘monitor’ on player’s side of upper bout

Arnold did this with the Ergo basses. I would talk to a luthier.

 

my version

2021 Castagne SE (SOLD) - Bresque Double Basses

The peculiar shape inside allows for a magnetic door to close the hole neatly.

 

Does the hole(s) improve the bass response of the instrument, by lowering the hemholz freq?

 

I don’t know.

What I do know is that the player appreciates the directed sound in a busy orchestral setting, and users report they can feel the sound in a different way with the port open.

I quote the owner:

“I’ve found that the port is the most handy when in a larger orchestral setting. Being able to hear your own sound in a section full of basses is useful with intonation (as you can hear yourself better!). I’ve found it useful in both loud and soft sections. (Although it can add a little volume, so maybe not consistently soft pieces). Sometimes I enjoy playing with it open doing solo and practice work too, for the simple enjoyment of not only hearing, but feeling whatever you input into the sound.”

 

Can anyone articulate a downside to this mod?

 

i tried for a long time to achieve a reliable adjustable aperture using magnets/sliders/rotating thing etc. In the end, it became too complicated and i didn’t want to lumber a buyer with something that rattled or got stuck or broke either short term or long term.

You will not be able to know anything meaningful about the helmholz relationship without knowing volume and area of existing sound holes anyway.

I suggest you decide whether you want the “monitor” function and if so, plan how to reinforce the hole. That will give you your size constraint. remember there are linings inside the ribs, probably bigger than the outside linings if present.

 

The port will allow to enter the bass larger rodents that couldn't possibly squeeze in through the f-holes.

 

Internal DB duster

P.S. I can address some tone and sound related questions as they apply to my Alcoa. The location of the port is very important. I play with my access port open when I'm desperate to hear my DB more and when I am not using amplification. I really cannot confidently say it helps -- if it does help, it's very subtle. But, my access port is in the driver-side C, about 2 feet below my ears. From testing a bit, I suspect if there was a similar sized port on my driver-side upper bout, it would help a lot.

Also, tone coming from inside the DB is very unclear, vague and echo-ey. Tone inside of the DB is also not optimal for amp pickups or mics, for the same reason.

Again, these observations are from my Alcoa which I would stress is tonally very different from a fine wooden DB.

 

At the beginning of the thread, you were considering drilling into the side of a plywood bass. If that was still your intention, I think you may have grabbed the wrong bass in your post-dryer-wrestling frenzy...

 

My bass carved has small ff's and poor low frequency response that's why I asked about these sound ports lowering the helmholtz frequency of the body and improving the low response?

 

As regards selling it, you might want to talk to some of the university professors in your state or general area, see if they have students who are looking for a decent bass that someone is willing to part with for not too much money. A decent but ugly (within reason, of course) bass is better than no bass or a poorly set-up college bass, after all, and even if I was one of Jon Hamar's students in Knoxville, a 6 hour drive to the opposite side of the state for a halfways decent bass would be worth it if there wasn't one similar in my price range.

 

German bass would probably sound better with a metric-sized hole.