Tiny 2-way design w. 6.5" woofer

[Lomax]

First of all let me point out that I'm well aware that the sensible way to design a speaker is to start with the drivers to be used, then choose an alignment and design an enclosure, not the other way around.

However, for this particular project I have to choose drivers (6.5" & tweeter) based on an existing cabinet with some nasty restrictions (don't ask). The problem is that due to its design the cabinet has a very limited volume (3 liters) and the front baffle only has room for either a tweeter OR a port (maximum 40mm dia and 20cm length). Furthermore, the tweeter would have to have a fascia no more than 50mm in diameter. F3 doesn't have to be very low though as the system will be complemented by a sub, but the lower the better.

I would very much appreciate if anyone more experienced in the art of speaker building than myself could help me with some advice - which would you recommend out of the following three options:

1) 6.5" woofer and separate tweeter in sealed box
2) 6.5" coax in ported box
3) 6.5" fullrange in ported box

Knowing that:

- Drivers can cost maximum $200 for a complete pair
- Sound quality is more important than SPL
- QTC should (ideally) end up between 0.6 and 0.8
- System has to handle up to 60W (at least)

I have spent a couple of weeks looking at different drivers but I can't seem to find a solution that would acheive the desired results. At present I'm leaning towards the coaxial option as it would allow me to fit a port and it has proved difficult to find a separate tweeter within the required dimensions.

Any creative suggestions, recommendations or complaints would be greatly appreciated!

Lomax

 

[Jared]

when you say coax do you mean an auto speaker??

 

[7V]

Re: Tiny 2-way design w. 6.5" woofer

First of all let me point out that I'm well aware that the sensible way to design a speaker is to start with the drivers to be used, then choose an alignment and design an enclosure, not the other way around.

I can't think of a reason why either approach couldn't be used.

I think that you're right to say that the limited volume is the problem, particularly if you're talking 3 litres. I don't know a 6.5" driver that could go low enough to crossover to a sub in a 3 litre cabinet. Maybe in a car you could crossover at a higher frequency.

Steve

 

[Kanga]

You could use an SEAS P17REX COAX/F ($83 ea) in a 3 litre sealed enclosure with a Q of 0.8, which would naturally roll off with an F3 of 100Hz. Then use the sub from 100 Hz down. This would be like a satellite system. There's a shielded version available for use next to a CRT TV too.

I don't know anything about this driver, but SEAS is normally good stuff and it looks suitable on paper.

Mick

 

[planet10]

You could use an SEAS P17REX COAX/F ($83 ea) in a 3 litre sealed enclosure with a Q of 0.8, which would naturally roll off with an F3 of 100Hz. Then use the sub from 100 Hz down. This would be like a satellite system. There's a shielded version available for use next to a CRT TV too.

I don't know anything about this driver, but SEAS is normally good stuff and it looks suitable on paper.

This driver is fairly highly reguarded & one i'd like to try out sometime. And Phil Abbate has done a project with this driver and figured out an XO & such-- Diamond Monitor article.

For use with a sub you don't want a ported box. You might want to make it aperiodic thou... lower the Q a bit & flatten the impedance curve.

dave

 

[Edgar]

Take a look at this project: http://member.newsguy.com/~stigerik/html/gnurk.htm
I know this guy, he is a experienced designer, se his Griffin speakers.

Edgar

 

[navin]

at 3 lites would a 5" driver (co ax or otherwise ) be better. yes your Sd would be much less and that might limit your max SPL at say 100Hz but otherwise a 5" might be better mated to such a small box.