First DIY speakers...

[ksporry]

Hi guys,

I need some help with some DIY speakers I'd like to build.
I already have a shape design in my head and I found some links that explain how to build those cabinets. basially I plan to build fairly large curved floorstanding speakers. The speakers will be connected to a 15-20 Watt tube amp.

Here are the topics I could use some help with:

1)
Volume of space within the speaker: I was considering using 3 drivers; a bass driver of ca 10", a mid range range driver of ca 6", and a tweeter.

I was considering separating the space between the bass and the other two drivers. For bass reflex of the bass driver, I was thinking of keeping the bottom of the speaker open, is that a good idea, or do I better use a classic rear firing bass reflex port? The mid range and tweeter driver part will have their own rear firing bass reflex port.
Potentially, if I can find the right shape/object, I'd like to build the tweeter in the same style as the smaller 800 series of B&W.

With this in mind, how do I determine the space required for each section?

2)
Keeping in mind that I want to hook it up to a 15-20 Watt tube amp, can someone recommend the appropriate 3 drivers that would do the job, including schematics for crossovers for those drivers?

Alternatively, I found this website http://http://www.gui-sound.com/
where they have some fancy looking drivers. I may be able to obtain some through friends I have in Taiwan, so obtaining them should not be difficult.

However, I don't know anything about crossover design. How do I determine the crossovers for drivers? Would someone be willing to draw out some schematics for me if I state which drivers i want to use? I understood that crossovers do affect each other, so they probably should be designed for the specific speaker combination I want to use.
Any help in this field would be useful.

I guess the core of my question here is how to determine the circuit for speaker crossovers.
As I said, I don't mind using some tried and tested designs that would be acceptable for my application.

Thanks for your help!

PS I would consider using cpmbinations of existing speakers, eg Monitor Audio RS1 for mid range and tweeter, plus another speaker for bass, but I would imagine that the crossovers for bass and for mid range/tweeter would interfere with each other, is that correct? Or could I use that approach?

[Glowbug]

Personally, if this is your first project, I would stick to a tested design, and save designing Xovers for later projects

What kind of music do you usually listen to? Will you need a lot of bass extension?

[Studio Au]

Curved floor standing speakers? Can you elaborate, drawings?

+1 for the tried and tested design. Perhaps build a 2 way, simple mid & tweeter.

You can then if you want or need add a woofer to each in a separate cabinet like you want and power it with a plate amp which has changeable cut off points.

I choose to purchase a Behringer DCX2496 (on ebay for 110gbp) as everything is adjustable, you can tweak the crossover on the go, however does require many more amplifiers.

Good luck

[mattmcl]

+1 on using a proven design. You will need very high efficiency drivers and excellent xovers to get the most out of that tube amp. I can't recommend any particulars as I'm in the high-power solid state camp.

[ksporry]

I mainly listen to Jazz and Blues, sometimes a bit of Latin.
I also occasionally listen to Taiko (Japanese drums).

I too would prefer a proven design as I would guess it'd be easier to implement.
If I make the front detacheable somehow, with rubber seals of some sort to prevent any potential rattling, I could always replace the drivers and crossovers at a later stage.

Have a look at this threat for the curved speaker design:
DIY Speaker With Curved Sided Cabinet - Club Polk

Mine would be a little bigger, depending on what I do for a 3rd driver for bass.

I'm not so sure about a digital unit in a chain of low power analogue tube technology...

If someone could provide me with links or info on 2 or 3 way speak designs that have been proven in the past and are suitable for low power tube amplification, that would be great!

[Moondog55]

Well if you listen to Taiko, you WILL need bass, but from memory of my last live concert it isn't very deep bass so you will need the 10 inch, but to make the design easier try a 2.5 way speaker with a first order electrical roll-off on the bass driver with the biggest coil you can afford, I find that between 6mH and 8mh works fine on an 8R woofer.

Then just design a 2-way for the 6inch and tweeter.
Do you already have any drivers or components?
What is your budget, dollars/pounds become important and things add up very quickly.
Good rule of thumb I was given many years ago on stereo was 1/3 amp; 1/3 speakers; 1/3 room/ this can also be given for DIY speakers. 1/3 box; 1/3 drivers; 1/3 crossover

Regards
Ted

[nad]

Originally Posted by Moondog55

Good rule of thumb I was given many years ago on stereo was 1/3 amp; 1/3 speakers; 1/3 room

Pardon my question, but what about the source?

[Moondog55]

Whoops
Absolutely right
my Mistake!!
That should have been 1/3 three times, source ( in those days TT or Reel to reel ) amp and speakers Later transposed to equal quarters to allow for the room.

But still good rule of thumb, most of us when starting out tend to forget or just don't know that the room dominates.

[nad]

Originally Posted by Moondog55

But still good rule of thumb, most of us when starting out tend to forget or just don't know that the room dominates.

I'm living the room acoustic battle at the minute and it's hurting my head!

Good advice though!

[ksporry]

Well, cant do much abou5 the room. The amp is a cheap Chinese tube unit. I expect to pay vs 200 to 300gbp on drivers. Box will be dot, so could be anything.
I guess. For bass I would need at least 2 drivers (one for bass, and a full range driver for the rest potentially) or 3 way if using conventional speaker build up.