Speaker cabinet

[Anonymous]

What should I make them out of?

The sizes and designs are easy maths but should I make 'em from MDF and veneer it (cut my own) or solid hardwood?

I ask as a lot of them are MDF and I wonder if this is a sonic issue.

 

[SketchUp Guru]

I think MDF is used because it tends to be conisitent in density throughout. Probably used for the same reasons you wouldn't use it on a violin or guitar.

I'm just talking through my hat, though. I think my little transistor AM radio sounds just fine.

 

[Paul Chapman]

Someone once told me that concrete was best :shock: But it might knacker your blades :wink:

Paul

 

[RogerS]

It's density, you're after, Tony. In an ideal loudspeaker the cabinet does not vibrate at all...hence concrete!

You'll find all sorts of damping stuff glued to the inside of soeaker cabinets..for the same reason.

And a little bit of British audio history. I was at school with Spencers' son and still have my BC1's!

And, as an engineer, you will appreciate this!

 

[cutting42]

I was at school with Spencers' son and still have my BC1's!

Me as well, not found many better speakers for sensible money.

 

[Paul Chapman]

And, as an engineer, you will appreciate this!

I just read that, Roger, and now I realise why I would never have made it as an engineer :shock:

Paul

 

[MIGNAL]

I think you will find that speaker designers differ in the material they stipulate in their particular designs and the effect it has on the sound. I've noticed that a lot of the higher end hi-fi are now using void free birch ply but certainly chipboard, MDF and various hardwoods have been used.

 

[colinc]

I believe a lot of DIY builders will argue for Birch Ply over MDF.

There is a lot of information and discussion about materials on the speakers forums here http://www.diyaudio.com/forums/

regards

Colin

 

[Anonymous]

Thanks guys

some intereting stuff to read there

 

[johnelliott]

Birch ply is too stiff and will vibrate at certain frequencies and not others, therefore colouring the sound
MDF will have far less effect on the sound, which is what you want

John

 

[Racers]

Hi, John

I would like you to say birch ply is to stiff to Dick Shahianian (http://www.shahinianacoustics.com/) I bet he would have something to say about that. I have heard most of the range and I can say they are not coloured, I own the Arcs which is the only MDF one and would love a pair of Hawks but at £9000 I don't think I could slip that one past the wife.

Their is no best material to make any thing out of, if the cabinet is well braced it shouldn't mater that much.

Pete

Roksan Xerxes artemis 10x4mk5 Naim 62 diy Supercap diy 135s Arcs if that means any thing to any one out there :wink:

 

[ike]

John wrote,

Birch ply is too stiff and will vibrate at certain frequencies

Just about any material will. Everything resonates.

Ike

 

[JFC]

I used to make speakers for a church pipe organ supplier and he wanted only MDF .

 

[johnelliott]

Hi, John

I would like you to say birch ply is to stiff to Dick Shahianian

Put Mr Shahianian in front of me and I will be happy to say it to him. I really don't care how much his stuff costs.

As someone who works with birch ply and MDF everyday, and who has some knowledge of acoustics and speaker systems, I stand by my previous statement

John

 

[johnelliott]

John wrote,

Birch ply is too stiff and will vibrate at certain frequencies

Just about any material will. Everything resonates.

Ike

Pick up a piece of birch ply and tap it, then do the same thing with a similarly sized piece of MDF, and you will hear what I mean
John

 

[colinc]

I said the ply/mdf choice was arguable!!

:lol:

colin

 

[ike]

John,

John wrote,

Quote:
Birch ply is too stiff and will vibrate at certain frequencies


Just about any material will. Everything resonates.

Ike

Pick up a piece of birch ply and tap it, then do the same thing with a similarly sized piece of MDF, and you will hear what I mean
John

I wasn't contradicting you about MDF/Ply. I wouldn't use ply for a speaker cabinet either. If MDF didn't exist then I would. :wink:

Ike

 

[-David-]

Hi Tony

Basically your enclosures should be solidly made, heavy, internally braced, internally dampened, airtight (unless ported), resonant free, isolated from the floor as much as possible. When at a reasonable volume the theory is that you should not feel vibration if you were to put your fingertips on them (more easily said than done).

Take a look at this site -

http://www.tnt-audio.com/clinica/nues_e.html

It will also help you with speaker cables - that is making your own as opposed to spending £7000 for a 4M pair of Nordost Valhalla's.

Have fun

David

 

[Anonymous]

Hi Tony

Basically your enclosures should be solidly made, heavy, internally braced, internally dampened, airtight (unless ported), resonant free, isolated from the floor as much as possible. When at a reasonable volume the theory is that you should not feel vibration if you were to put your fingertips on them (more easily said than done).

Take a look at this site -

http://www.tnt-audio.com/clinica/nues_e.html

It will also help you with speaker cables - that is making your own as opposed to spending £7000 for a 4M pair of Nordost Valhalla's.

Have fun
David

Thanks David, useful stuff

Cables are not a concern. I have followed the debates about speaker cables for 15 years. As an engineer who has been involved in testing cables (including speaker cables and 'blind' listening tests) and subsequently as an academic who has read much published (not by manufacturers of cables!!!!!) material in this area I have concluded that there is absolutely no discernable (or measurable - even with extremely precise instruments) difference in the signal between 'exotic' oxygen free, solid silver etc., etc. cables at £1000 per meter and 'average' speaker cables at around £5 per metre. No signal change means the same sound at the speaker. I certainly could not hear any difference in the sound during the tests I was invovled in.

This subject was also exhaustible discussed for many years by the likes of John Linsley Hood (arguably one of the very best amplifier designers) in Electronics and Wireless world. The outcome of these published experiemnts and discussions concluded that the 'golden ear brigade' are seeing (hearing) the emperors new clothes.

OK. With very cheap, thin cables coated in poor quality insulation, the sound will be affected, but I am talking about 'decent' lower priced speaker cablers versus the 'exotic' cables here.



One pays the money and makes your choice - £5/m for me.
If people think they can hear a difference with £50/m cables, fair play to them - it can't be measured though and they are probably the only ones who can hear it :wink:


However, the choice of amplifier, source and speakers makes huge differences, hence my desire to get the enclosure right.

If you're interested, the amplifier driving these speakers is made by Rega (Famous for thier Planet turntables)

 

[johnelliott]

There is one parameter of speaker cabinet design that can be controlled by enthusiastic music lovers and woodworkers, and that is cabinet size. Quite simply, the bigger the better.
It's the compliance thing. To produce a given volume of sound the speaker has to move a given volume of air. To do this it has to act like a piston. As it moves backwards and forwards so it compresses and decompresses the air inside the cabinet. The more the internal volume of the cabinet the less the percentage change for any given speaker movement and the easier therefore this movement is, and the less amplifier power is needed for any given volume of sound.
The speakers sound better too.

Sine the sixties domestic hifi speaker design has been driven by the understandable desire to produce smaller and smaller boxes.

I once made a really BIG pair of speaker cabinets. They were each the size of an average dopmestic fridge. I used a couple of 15" speakers (although that isn't terribly important, 12 or even 10 would have been OK).
These speakers were loud enough that on half volume they provided enough sound for a ballroom full of 200 dancing people, and the bass could be clearly heard throughout the fair sized hotel. The amplifier? A 10w Bush music centre.

John