AudioNirvana 12" 5.6 cabinet details

[tsiros]

Hello all

I am in the process of planning the cabinet construction for these audio nirvana 12" cast frame speakers. I am a complete and utter noob, the only time i have done anything remotely related to speaker DIY is when i took the silly two way yamaha satellite speakers and cut a hole in their back and inserted a toiletpaper center in there with hole diameter and tube length similar to those of similar speakers. ANYWAY.

I listen to all sorts of music, from full blown orchestra to chamber music... from Glass Hammer to All Shall Perish (i will save you the anguish of listening to an example. Imagine a diesel truck trying to start in a cold cold morning. I also play the electric and i am mostly a technical death metal player) and from a capella to... well... this ... or this... Anyway, again...

I am semi-decided to use the 5.6 cabinet, mostly because commonsense audio suggests it. If someone has a cabinet to suggest that is easy to build but doesn't sacrifice sound quality significantly, i am open to ideas.

I was planning to use plywood ~20mm, because i thought it would be more rigid than MDF, but a friend says that MDF has more uniform characteristics: its properties don't change as much as plywood does.

1. Do i want to use MDF or plywood? I am kinda cheap, BUT i also want it to sound decent.
2. Is 18mm thickness good? if i go 22mm would it be better?
3. Do i butt-joint it? do i glue it?
4. Does the speaker rim HAVE to be flush with the baffle? same friend says yeah or else the sound will suffer. But i see speakers from dynaudio (example) that don't seem to be flush I think making the 'step' in the front baffle will be a small challenge. I have no special tools... I have a dremel... and some duct tape though.

those are my main problems.

I want to paint it rather than lacquer it, because it is cheaper, i do not care AT ALL at the aesthetics of it (sorry if that sounds cheap to you. I want my amp's faceplate to look as pretty as possible, though... that counts for something, right?).

[4krow]

Heh Heh, I agree with a lot of what you say. I made quite a different cabinet for my AN speakers. They are the 8" cast, alnico magnet. Anyway, I tend to think that I like the plywood at 22mm better than the MDF. Gives some of it's own flavor I guess. Now, I don't really disagree with those that think the cabinet should not 'speak for itself', but you can dampen an unruly cabinet better than liven one up. Anyway, David Dicks, the founder of AN and I were talking once about this, and he said that regardless of speaker size, the experience can be maximized by nearfield listening, thereby lessening room acoustics,etc. As far as glue, I tend towards using polyurethane or at least Titebond III. This also helps seal the enclosure. Butt joints are fine, especially if your going to paint the cabinet, and don't care so much about the looks. Don't worry about the driver being flush with the cabinet, as that effect is minimal in the first place. More importantly would be speaker placement, room acoustics, etc. These drivers that you will be using are REALLY efficient, so what are you going to drive them with?

[tsiros]

lm4780

the reason is that i need something good enough but also simple to build NOT because i am bored or do not want to build something (i enjoy assembling things! from my tamiya nitro force, to a discrete 100W amp). The reason that i want something simple to build is that so i minimize the chance something will go wrong or that the end performance of the amp is affected by my building skills. It's far more certain that the end result will fall close to the specifications.

[planet10]

Keep in mind that it takes about 32mm of MDF to be as stiff as 18mm of good ply,

In a box this size, you have a lot of wall panel. It will need to be well braced to avoid the box panels becoming seconday radiators.

dave

[aptquark]

Ya..what Dave and 4krow said. You could use both MDF and ply to add diff res. frequencies into the mix. I did this with my 2.8 AN 8 inch boxes that I built for the cast frame 8's. I know that there are better options for the AN speaker boxes..but have yet to come across any (from these gurus here).

KALI TIXI MALAKA!

[tsiros]

I would very much appreciate it if you refrained from using such language.

[FullRangeMan]

Tsiros:
Hi, I would suggest these suggestions on this old topic about fullranges x cabinets.
Please Note the post #25 from ERIKB1971, very good tip to reduce inside resonances in a box.
How to Treat Passively Peaky FullRange Drivers
Good Luck and inform us from the obtained results please.

[tsiros]

i think those holes disperse the sound waves. something like that. not sure. don't know the correct english term, i'm a greek physicist

[FullRangeMan]

Originally Posted by tsiros

1. Do i want to use MDF or plywood? I am kinda cheap, BUT i also want it to sound decent.
2. Is 18mm thickness good? if i go 22mm would it be better?
3. Do i butt-joint it? do i glue it?
4. Does the speaker rim HAVE to be flush with the baffle? same friend says yeah or else the sound will suffer. But i see speakers from dynaudio (example) that don't seem to be flush I think making the 'step' in the front baffle will be a small challenge. I have no special tools... I have a dremel... and some duct tape though.

those are my main problems.

I want to paint it rather than lacquer it, because it is cheaper, i do not care AT ALL at the aesthetics of it (sorry if that sounds cheap to you. I want my amp's faceplate to look as pretty as possible, though... that counts for something, right?).

Questions:
1) Baltic Birch plywood is beter sound, But MDF 30mm could be more durable and strong to a baffle.

2) For a biig fullrange baffle I could use MDF 30mm or BB plywood also 30mm(not 20mm), and other sides plywood 20mm.

3) If possible do both butt-joint and glue, as FR made inside resonances in all the audible range.

4) I do not like flush mounting, it is a precision work, takes time and benefit are very low. I prefer instead to cover the outside baffle with 5 or 10mm black felt layer to the FR alloy frame and the wood baffle does not make contact with each other.

Some DYNaudio speakers use suspended, float mounting baffles;
If good looking not important you would coat/overlay the entire outside of the box with black felt 5mm, which reduces a little more resonances in the room and costs much less than prepare/sanding, paint and polish.
Regards

[FullRangeMan]

Originally Posted by tsiros

i think those holes disperse the sound waves. something like that. not sure. don't know the correct english term, i'm a greek physicist

Yes, the assimetric holes reduce internal ressonances which may disturb the paper cone.