Not exactly woodworking, but my latest shop project

[tvrgeek]

My desktop stereo has a horrible 113.48 Hz resonance/mode. So I made a trap to sit behind the desk and absorb the peak. I did not want to do digital eq. in JRiver player as I also use headphones that do not need eq. Even if not doing the next batch of picture frames, staying busy in the shop.

Does MDF count as wood?

 

[ssmith]

Wow, that's a creative way to solve the problem. You just never know what you'll see here!

 

[Oka]

'bout as much as formica ........

 

[Martin Roper]

Does MDF count as wood?

MDF is to wood what Velveeta is to cheese.

 

[tvrgeek]

Or lite is to beer.

 

[Graywolf]

It is a wood substance

 

[JNCarr]

Or SPAM is to meat...

 

[Oka]

LOL Best answer this will go into my lexicon.

MDF is to wood what Velveeta is to cheese.

 

[Dee2]

Are we hinting for a new contest?

 

[MikeH]

I have no clue what this even means!

 

[tvrgeek]

If anyone cares, it did not work. Got it tuned OK, but as the pipes are all constant diameter, they resonated at the third harmonic and surprisingly the tubes themselves resonated. Next try would be an MDF box with an old sub wooer in it as a passive radiator.

 

[mangoey]

super cool

 

[MTod]

If anyone cares, it did not work. Got it tuned OK, but as the pipes are all constant diameter, they resonated at the third harmonic and surprisingly the tubes themselves resonated. Next try would be an MDF box with an old sub wooer in it as a passive radiator.

What if you were to use a heat gun and melt some irregularities into the pipes?

 

[tvrgeek]

Michael, good idea but they pipes are just not rigid enough. Maybe if I used the thicker sanitary pipes but I used the thinner vent or garden drain pipes. 4 more 8 footers is more than I want to spend on that rabbit hole, so off to a different one.

Modeled a 6th order bandpass enclosure for an 8 inch woofer I have sitting around. I can do proper golden ratios in the box and even odd angles. Q should be much higher. A simple resonator is only Q of 1 being a first order filter. A 6th order should be more like 5 in reality and much closer to the room mode I need to battle. Easier to tune as it is the port length that one changes. All out of MDF, so I have to make a run. For a box with two .3 cu ft chambers, I think I can get away with 3/4. MDF is actually close to perfect for enclosures with the exception of using HDF for front baffles.

In the mean time, I got my Denafrips R2R DAC and wow, I really mean wow! I am cheap and it is worth every penny. Way off subject I know. On subject, collecting non-copyrighted scroll saw patterns to give my first tries at for next month.

 

[WallNutz]

How are you measuring the results? I’m just curious because I find this fascinating.

 

[tvrgeek]

Calibrated USB mic and PC applications REW, TrueTRA. Many years ago I use a phono cartridge to investigate various wood, composite, and laminations to determine the best box material. In those days PB was SOP, but MDF is far superior. I had never heard of HDF other than Masonite back then. My subs are laminated MDF, ceramic plates, and plywood. I had intended to make some bookshelf with beautiful exotic woods we used to be able to get cheap as flooring, but acoustically they were a disaster.

Flooring is a often forgotten material. My first set of kitchen cabinets were from oak cutoff and seconds.

If anyone is serious into speaker building, PM me as once you get past making boxes, it is no longer woodworking. There is a lot that could be done with CNC that I can only approximate with a rasp. Good design is still only about 3/4 science. A bit of art and experience is still in the mix.

 

[Jack A.]

What are the ceramic plates in the sub for?

 

[tvrgeek]

Rigidly and lowered the resonance. I laminated veneer, plywood, ceramic, MDF as the panels. I used some elastomer glue from McMaster I don't remember. Today I would have used a layer of MDF and a layer of HDF veneered. Down firing Peerless XLSS. Meets WAF.

 

[Jack A.]

Gotcha, makes sense. When I think of ceramic, I think rigid and reflective. That seemed weird for a speaker enclosure unless maybe it was at the end of some sort of complicated resonator.

 

[Willemjm]

^^^^^
I can get some pretty good sound by buying different stuff from different places and slapping everything together.

But what you guys are talking about is way above my pay grade.