Previous Thread
Next Thread
Print Thread
Rate Thread
Page 74 of 89 1 2 72 73 74 75 76 88 89
Re: Lets plan a theater space
AAAA #423941 03/10/17 02:08 PM
Joined: Jan 2007
Posts: 10,490
Likes: 116
M
shareholder in the making
Offline
shareholder in the making
M
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
AAAA #423942 03/10/17 04:10 PM
Joined: Jul 2009
Posts: 2,281
connoisseur
Offline
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
AAAA #423943 03/10/17 05:50 PM
Joined: Mar 2014
Posts: 1,593
Likes: 1
A
AAAA Offline OP
connoisseur
OP Offline
connoisseur
A
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
AAAA #423947 03/10/17 07:00 PM
Joined: May 2014
Posts: 1,170
Likes: 6
M
MMM Offline
connoisseur
Offline
connoisseur
M
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
AAAA #423948 03/10/17 07:25 PM
Joined: Jul 2009
Posts: 2,281
connoisseur
Offline
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. smile


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
AAAA #423953 03/10/17 10:25 PM
Joined: Jul 2009
Posts: 2,281
connoisseur
Offline
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
Gr8_White_North #423962 03/11/17 10:10 AM
Joined: Mar 2014
Posts: 1,593
Likes: 1
A
AAAA Offline OP
connoisseur
OP Offline
connoisseur
A
Joined: Mar 2014
Posts: 1,593
Likes: 1
Originally Posted By Socketman
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. smile


Ditto! And do tell.

Re: Lets plan a theater space
Gr8_White_North #423966 03/11/17 12:02 PM
Joined: Mar 2014
Posts: 1,593
Likes: 1
A
AAAA Offline OP
connoisseur
OP Offline
connoisseur
A
Joined: Mar 2014
Posts: 1,593
Likes: 1
Originally Posted By Socketman
And then there is This Guy


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
AAAA #423977 03/11/17 05:51 PM
Joined: May 2014
Posts: 1,170
Likes: 6
M
MMM Offline
connoisseur
Offline
connoisseur
M
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
AAAA #423980 03/11/17 07:18 PM
Joined: Mar 2014
Posts: 1,593
Likes: 1
A
AAAA Offline OP
connoisseur
OP Offline
connoisseur
A
Joined: Mar 2014
Posts: 1,593
Likes: 1
Ian is a DIYer. Think about it. smile

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.

Page 74 of 89 1 2 72 73 74 75 76 88 89

Moderated by  alan, Amie, Andrew, axiomadmin, Brent, Debbie, Ian, Jc 

Link Copied to Clipboard

Need Help Graphic

Forum Statistics
Forums16
Topics24,940
Posts442,457
Members15,616
Most Online2,082
Jan 22nd, 2020
Top Posters
Ken.C 18,044
pmbuko 16,441
SirQuack 13,840
CV 12,077
MarkSJohnson 11,458
Who's Online Now
0 members (), 565 guests, and 1 robot.
Key: Admin, Global Mod, Mod
Newsletter Signup
Powered by UBB.threads™ PHP Forum Software 7.7.4