3-way speaker project started. Advices are welcome :)

[zafira1981]

Well, after collecting as much information as I could, I started designing my 3-way speaker system.

Finally I found some nice speakers in Argentina. The brand is "GB-audio" and seems to be the only good speaker manufacturer in my country.

So, the 3-way configuration is:

woofer: GB-Audio B-10K
Kevlar, 90W RMS, 8 ohms VC Ø38mm former de kapton Xmax 4mm.
Rcc 6.4Ω / FR 26.35Hz / Qts 0.392 / Vas 135ltrs. / BL 10.58N/A / eff 89.30dB Respuesta Fo~2.500Hz
Recomended enclosure: bass-reflex
VB 80ltrs (S=4), FB 27Hz, F-3 32Hz, port. dia 100mm / PL 330mm
VB 120ltrs (S=5.7), FB 27Hz, F-3 27Hz, port. dia 100mm / PL 200mm
http://www.gb-audio.com.ar/images/B-10K.JPG
u$s 80 each

mid-high: fostex FE167E
http://diyaudioprojects.com/Drivers/FE167E/
€82 each (France)

tweeter: Audax TW010F1
http://www.madisound.com/catalog/pro...products_id=96
u$s 22 each (in Argentina)

Crossover points: 300 hz - 10 khz

mid & tweeter in one sealed enclosure. volume =12 liters
Woofer in a bass-reflex enclosure volume = 84 liters

The enclosure will be made with two types of wood.
5mm plywood, maybe military type (more layers) for the inner box, then a 5mm MDF for external box.

Here some pictures of the preliminary design in google sketchup.









height: 1,1m
top width: 20cm
bottom width: 40cm
depth: 35cm


please tell me who you think. thanks

[pacificblue]

Nice looking woofer.

The Fostex deserves a better tweeter. We call that type of tweeter 'squeak pill' in Germany and that describes it very good. The price in Argentina is crazy.

Why don't you try it without tweeter first? The Fostex might be good enough that way.

At 300 Hz the human ear can still locate things quite well and you could get an effect that some instruments and vocals will seem to come from the top of the speaker and others from the bottom. To avoid that, you can either choose a lower crossing frequency between bass and mid or move the woofer closer to the Fostex.

[zafira1981]

Originally posted by pacificblue
Nice looking woofer.

The Fostex deserves a better tweeter. We call that type of tweeter 'squeak pill' in Germany and that describes it very good. The price in Argentina is crazy.

Why don't you try it without tweeter first? The Fostex might be good enough that way.

At 300 Hz the human ear can still locate things quite well and you could get an effect that some instruments and vocals will seem to come from the top of the speaker and others from the bottom. To avoid that, you can either choose a lower crossing frequency between bass and mid or move the woofer closer to the Fostex.

I think it's a good idea not to have a tweeter at the begining. What I think I will do is first try it without a tweeter and then connect one and see how it sounds, but not making a hole in the box, just connecting and placing it in the top of the cabinet.

I didnt know that the audax was a bad tweeter. I have lot to learn, the main problem is that is difficult to get good drivers in my country.

What tweeter would you recommend?


About the 300hz crossover point, maybe I can change it to 200 hz.. what's the ideal point? I will have to build a big inductor .. good that I have plenty of room


thanks,
Jorge.

[pacificblue]

Audax is a good manufacturer. Like most manufacturers they have to address different budget levels and the tweeter you linked to is for the low budget market.

Did you check the Full Range sub-section in the Loudspeaker section? There must be others that use the FE167 with an additional tweeter. You will probably find good recommendations and sound descriptions there.

If you want to leave the woofer so far away from the FE167, you will probably need a cross-over frequency in the range of 100-150 Hz. Either that or bring the woofer to within 280 mm of the FE167.

[planet10]

The audax tweeter is not a terrible tweeter, the issue you run into mating it with FE167 is that it is not efficient enuff... its dispersion characteristic is also not a great match. My preferred version of this tweeter are the $1 each ones from ApexJr (there may still be a special diyA price).

With the FE167 you can get away without a tweeter, but some find a cap XOed tweeter (somewhere between 12-17k) adds some air to the presentation. A horn with limited disprsion is usually a better match to the 167.

BTW, FE167 will make a killer mid-tweeter. If you search the FR forum you can probably find some OBs using the FE167 similarily.

dave

[planet10]

Originally posted by pacificblue
If you want to leave the woofer so far away from the FE167, you will probably need a cross-over frequency in the range of 100-150 Hz. Either that or bring the woofer to within 280 mm of the FE167.

Very good point. When we were developing Tysen (A thread for Tysen and variations on FAST) you can see in the 2nd post that we started with the woofer at the floor. With the 333 Hz XO we had to invert the woofer box to avoid some serious ripple in the FR.

dave

[zafira1981]

Originally posted by pacificblue
Audax is a good manufacturer. Like most manufacturers they have to address different budget levels and the tweeter you linked to is for the low budget market.

Did you check the Full Range sub-section in the Loudspeaker section? There must be others that use the FE167 with an additional tweeter. You will probably find good recommendations and sound descriptions there.

If you want to leave the woofer so far away from the FE167, you will probably need a cross-over frequency in the range of 100-150 Hz. Either that or bring the woofer to within 280 mm of the FE167.

I can move the woofer up but dont know if I can move it that closer to the FE167, I have to check the diameter and see if can be placed 280mm near the fostex. I put the woofer there with no specific function.

Can the FE167 reproduce lower frequencies like 150 hertz? Is recommended to have the crossover that low?

Originally posted by planet10
The audax tweeter is not a terrible tweeter, the issue you run into mating it with FE167 is that it is not efficient enuff... its dispersion characteristic is also not a great match. My preferred version of this tweeter are the $1 each ones from ApexJr (there may still be a special diyA price).

With the FE167 you can get away without a tweeter, but some find a cap XOed tweeter (somewhere between 12-17k) adds some air to the presentation. A horn with limited disprsion is usually a better match to the 167.

BTW, FE167 will make a killer mid-tweeter. If you search the FR forum you can probably find some OBs using the FE167 similarily.

dave

Okay, for now, no tweeter will be used. I will have time to find a good tweeter. The only reason that I wanted to use a tweeter is that at 10-20khz the fostex lows the SPL a bit.

[zafira1981]

Originally posted by planet10


Very good point. When we were developing Tysen (A thread for Tysen and variations on FAST) you can see in the 2nd post that we started with the woofer at the floor. With the 333 Hz XO we had to invert the woofer box to avoid some serious ripple in the FR.

dave

I will see what happens if I make the top of the woofer enclosure wider to be able to move the woofer up.


Another point that I'm not sure that if it's ok is the port of the woofer box. It's large and the port is near to the rear panel of the box. Is there any limitation in the minium distance between the port and the back panel?

[kenpeter]

Have you looked into Selenium's ST324 slot tweeter?
I'm making crazy assumption you can get Brasil parts in Argentina...

[pacificblue]

To be on the safe side, try to have more distance between the tube and the enclosure than the tube's diameter. You can use angled tubes as well, e. g. like this.
If the port length is a calculated value as opposed to a tested one, one often ends up with a 20-25 % shorter port than theory predicts.
Then there is the possibility to use a passive membrane instead of a reflex tube.