Ported Sub to Tapped Horn. Questions before starting

Rubens Ben

New member
Jun 26, 2019
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Tel Aviv
Hi Everyone :D

I am kind of new here and after having built few vented enclosures for bass / midbass drivers, I decided to go forward and build Tapped Horn types in order to get the best of my RCF LF15N401 with this plan :
https://www.freespeakerplans.com/plans/14-plans/basscab/10-apache-h15 .

But before-hand, I have few questions in mind :
  1. Vibrations : I need to have my setup (turntables + mixer) diretly on the top of the enclosure : How will it goes with the bass vibrations ? Will I be able to operate everything smoothly or will it be unpracticable ? If too shaky, what would be a solution to have my setup on the enclosure or as close as possible ? I need to be ultra compact
  2. Plan Optimization : On the plan, it's written that many drivers are fittable, but I know that each driver has it's own characteristics, so on it's on enclosure size. How could I optimize this plan for the RCF LF15N401 and be sure I'm getting the best of the driver ?
  3. Wood type : Is it ok if I use MDF or I strictly need to use plywood ?

I am also open to any other "simpler" design that would give close results to this design, the idea here is to have an enclosure that give the most powerful SPL / DB for the minimum power needed.
Ex : https://www.gearclubdirect.com/rcf-passive-ip55-800w-15-neo-subwoofer/ ?

Here is the spec sheet of the driver : https://www.rcf.it/c/document_library/get_file?uuid=2f6242ce-9d1e-4cf4-b611-d85de1526836&groupId=20195

Here is a picture of the ported enclosures I have built for the record




Thank you in advance for your lights. BLESS
 

James McMullen

New member
Jun 24, 2019
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1. Sitting turntables on subs may not work so well with out some good isolation. (I've seen cardioid subs under a portable stage bounce a 200lb man around.)
2. I have no idea how you would determine that with a tapped horn. Perhaps there is software available such as with ported designs.
3. MDF is toxic to work with, I'd go with birch or at the very least wear a class 2 respirator in a well ventilated area when cutting it.
 

Rubens Ben

New member
Jun 26, 2019
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Tel Aviv
Thank for your answers Carl and James !

- Carl : Depends, how would it compare to a proper vented box ? the max distance wished for a proper audio experience would be 40/50m in my case

- James :
1. Got it, but I need to find a solution. Someone told me about building another similar enclosure and stack them together in order to cancel the vibrations. I was thinking building a metal structure around the enclosure and add a wood board on the top in order to not receive direct vibrations. Another friend told me about renforcing the enclosure with fiberglass.
2. Digging it :) ....
3. Got you and it's actually good you remind me that as I havent took my safety precautions.
 

James McMullen

New member
Jun 24, 2019
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The stiffer the enclosure the less it will vibrate. It will also increase the output of the box. An old trick with subs that aren't of the best construction is to reinforce the internal bracing. You may want to consider building an isolation platform that sits between your sub and turntable with neoprene/springs etc. Think recording studio. The more sensitive microphones are in shock mounts to reduce low end rumble. If it's a higher end studio the floors are on floated via iso blocks.

I looked around and found an article I read some time ago. Touches on some of your issues.

 

Roland Clarke

New member
Feb 22, 2018
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Hastings
The cab should work given the right speaker. My only reservation is that it may be tuned a tad low. You need a speaker with an extremely stiff cone and decent Xmas.
 
Oct 25, 2018
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Bideford, Devon. UK
Good luck with the build Ben, but study the frequency response of the design you choose carefully, as tapped horns don't go very deep for their size. Very high output, but limited low-end, perhaps -10dB at 30Hz. Good luck, Carl.
 

Max Warasila

Graduate
Feb 20, 2013
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Richmond, VA
MDF is *garbage* for pro sound applications. It's only real benefit is that it's cheap and somewhat easier to work with, but it's nowhere near stiff enough and the final design will weigh much more as a result of additional bracing and the higher density of MDF.