Re: Lets plan a theater space
|
Joined: Jan 2007
Posts: 10,490 Likes: 116
shareholder in the making
|
shareholder in the making
Joined: Jan 2007
Posts: 10,490 Likes: 116 |
This is a complex subject. The fundamental recipe for the cabinet after choosing the material and shape is to brace, glue, screw and add absorption. The devil of all of this is in the details.
The purpose of a cabinet is to prevent the sound from the back of the drivers from escaping into the room. One can say choosing MDF sucks because most of the sound goes right through it. Hardwood appears to solve that problem by trapping the sound but now the back pressure has to go somewhere so, presuming the cabinet is epoxied, screwed and sealed, it escapes out the drivers which of course interferes with the sound. Hence some type of damping is added to absorb the sound.
Usually the damping is loose but not necessarily. Gluing heavy damping material to the cabinet increases absorption but increases mass which increases the cabinet's resonant frequency. Bracing can then be added to further increase the resonant frequency so it's not objectionable but this has to be carefully designed as well because you can't just brace anywhere and with anything.
Using hardwood usually means having to add heavy damping that is glued to the walls and multiple hardwood braces to get the resonant frequency above 1 KHz. This of course is very expensive. Hence why MDF is chosen - less mass, lower resonant frequency and a bit of fill.
The bottom line is the designer should have considered all of this and selected the right materials and construction methods to optimize the speaker as a system. So don't mess with it...yet. Build this baseline design and then build others if you want to compare with the baseline.
|
|
|
Re: Lets plan a theater space
|
Joined: Jul 2009
Posts: 2,281
connoisseur
|
connoisseur
Joined: Jul 2009
Posts: 2,281 |
There is nothing that Mojo said that i can disagree with, i am not a speaker designer but i did stay at the Holiday Inn. Here's the thing about speakers, there is no formula for the perfect speaker. They all sound different to different people, in different rooms. I can not even grasp how many drivers that are available for purchase never mind the ones that are proprietary. Speaker design has come a long way what with modeling software and lessons learned from previous models and god knows how many hours someone like Ian spent in the anechoic chamber. At what point is enough , enough. Is the wood dense enough, too dense do i have enough stuffing the list is endless. Mojo mentioned resonance, now does the cabinet resonance detract from your enjoyment or add to it or is it hidden in the music. I think it depends on how critical of a listener you are. I mean how i listen to music and how my dad does/did are entirely different. Different music requires different listening styles.
I built with axiom driver because i was familiar with them and knew i couldnt F" it up to bad. I did end up putting quite a bit of poly in to bolster the low end as it was a bit thin, but also i did not port them. I dont think a lot of stuffing is needed for a ported design. My M80's have only a few ounces of poly in them. Honestly i say build them listen to them and then start with samll amounts of poly and work your way up.
DOG is GOD spelled backwards. What others think of me is none of my business. M80 V3 MY GLOSS Cherry
|
|
|
Re: Lets plan a theater space
|
Joined: Mar 2014
Posts: 1,593 Likes: 1
connoisseur
|
OP
connoisseur
Joined: Mar 2014
Posts: 1,593 Likes: 1 |
Wow. Awesome and thoughtful explanations guys. The plan was to stick to the design, and now I understand why. Starting to all gel now. Thanks!
|
|
|
Re: Lets plan a theater space
|
Joined: May 2014
Posts: 1,170 Likes: 6
connoisseur
|
connoisseur
Joined: May 2014
Posts: 1,170 Likes: 6 |
The talk about solid wood is interesting but also misses a mark totally.
Being a woodworker, I get to work with the stuff on a constant basis and as a result have gleamed quite a bit from that. Beyond staying at the Holiday Inn. Building speakers out of solid wood would be a step towards impossible. I have yet to find two boards of wood that are the same. It's a living thing and as such each part of the tree has grown up differently. I have had boards that came from the same tree, bookmatched so I know they are consecutive cuts, and yet when you work with them, they have different stresses and move in slightly different ways.
MDF is consistant. It has the same density throughout. It doesn't expand, contract, or move in un-uniform manner depending on direction of the grain as it has none.
You talk about resonance of the wood. Think about a Stradivarius, no two sound identical. It's wood and so it will give a different sound even if they are made identical.
just my two cents worth, wanted or not
Anthem: AVM60, Fosi DAC-Q5 Axiom: ADA1500, LFR1100 Actiive, QS8, EP500, M3, M3comp, M5
|
|
|
Re: Lets plan a theater space
|
Joined: Jul 2009
Posts: 2,281
connoisseur
|
connoisseur
Joined: Jul 2009
Posts: 2,281 |
Something that would be enlightening. Build multiple speakers from different materials.Make one out of MDF, another from Baltic Birch and then one from hardwood. The hardwood thing would be questionable since like matt said, different densities etc but also joining the pieces together. Lots of good food for thought. My big complaint, MDF is so messy and it really is hard on bits and blades etc.cant wait to start my new project if the weather ever clears.
DOG is GOD spelled backwards. What others think of me is none of my business. M80 V3 MY GLOSS Cherry
|
|
|
Re: Lets plan a theater space
|
Joined: Jul 2009
Posts: 2,281
connoisseur
|
connoisseur
Joined: Jul 2009
Posts: 2,281 |
And then there is This Guy
DOG is GOD spelled backwards. What others think of me is none of my business. M80 V3 MY GLOSS Cherry
|
|
|
Re: Lets plan a theater space
|
Joined: Mar 2014
Posts: 1,593 Likes: 1
connoisseur
|
OP
connoisseur
Joined: Mar 2014
Posts: 1,593 Likes: 1 |
My big complaint, MDF is so messy and it really is hard on bits and blades etc.cant wait to start my new project if the weather ever clears. Ditto! And do tell.
|
|
|
Re: Lets plan a theater space
|
Joined: Mar 2014
Posts: 1,593 Likes: 1
connoisseur
|
OP
connoisseur
Joined: Mar 2014
Posts: 1,593 Likes: 1 |
His design does look pretty advanced and no doubt it will be gorgeous. It would be pretty sweet to have access to that kind of CNC and design process.
|
|
|
Re: Lets plan a theater space
|
Joined: May 2014
Posts: 1,170 Likes: 6
connoisseur
|
connoisseur
Joined: May 2014
Posts: 1,170 Likes: 6 |
It is an interesting design. I can understand the desire to put your mark on the world and build you own stuff. But sometimes I wonder if it's worth re-inventing the wheel.
Bake your own DIY cake. YES. Most store bought ones are pretty awful.
Build your own car. NO. just becuase you can strap some wheels behind an engines doesn't make it better.
Anthem: AVM60, Fosi DAC-Q5 Axiom: ADA1500, LFR1100 Actiive, QS8, EP500, M3, M3comp, M5
|
|
|
Re: Lets plan a theater space
|
Joined: Mar 2014
Posts: 1,593 Likes: 1
connoisseur
|
OP
connoisseur
Joined: Mar 2014
Posts: 1,593 Likes: 1 |
Ian is a DIYer. Think about it. Here is where the cabinets are at with insulation. The ports are also fully assembled though not shown in the pic. The top flare is flush with the bottom of the window brace. The baffles are ready to be glued and screwed on. I'm just hesitating for the final seal. This is the I hope I didn't forget anything moment. lol. And test fitted to make sure everything makes sense and I didn't screw up. Seems ok.
|
|
|
Forums16
Topics24,940
Posts442,457
Members15,616
|
Most Online2,082 Jan 22nd, 2020
|
|
0 members (),
565
guests, and
1
robot. |
Key:
Admin,
Global Mod,
Mod
|
|
|
|