Diy Audax

sma · 2nd February 2004, 09:43 AM

Hi,

i have 1 pair of audax HM170G8 and 1 pair of audax TW034XO tweeter.i interest for building 2 way loudspeaker,anyone have suggest about box size and crossover schematic for this configuration?

Taco · 2nd February 2004, 10:27 AM

I only know the HM170G8, and this woofer works perfectly in an 18 - 22 liter cabinet. With a F3 of about 50 hz. A simple first or second order x-over suffices.

Ouroboros · 2nd February 2004, 10:34 AM

The TWO34 has its fundamental resonance below 900Hz, so it works well with a first-order crossover if you are setting the nominal crossover frequency to 3000Hz or so.

It WILL need a series L_C_R network across it to compensate for the rise in impedance at resonance. (Otherwise you'll find that your high-pass filter isn't behaving as you expected it to).

I use this tweeter myself with such a crossover with no problems.

(If no-one responds with the resonance compensating network values, I'll check this evening with what I used and post it tomorrow).

Chris Morriss.

Ouroboros · 3rd February 2004, 07:14 AM

As a resonance compensating network, I use a series L-C-R network of 1.2mH, 33uF, 10R across the tweeter.

sma · 3rd February 2004, 07:58 PM

thank you ouroboros.i will try your schematic..

any one have suggest for woofer box?

Ouroboros · 4th February 2004, 07:17 AM

To make a first order crossover work adequately, it would also be wise to place a network across the bass unit to compensate for the rise in impedance as the frequency increases. For the HM170G8, a series R-C network of 8.2R + 12uF is about right.

The resonance compensating network across the tweeter, and the inductance compensating network across the bass unit means that the drive units now present a much more constant impedance load to the crossover.

With these networks in place, you can then calculate the value of the series 'L' for the bass unit filter, and 'C' for the tweeter filter, assuming a constant 8R load. (It won't be perfect, but it will a LOT better than if the speaker impedance had not been compensated for.)

Taco · 4th February 2004, 08:06 AM

Quote:

Originally posted by Ouroboros
For the HM170G8, a series R-C network of 8.2R + 12uF is about right.

I used 10ohm + 10 uF zobel on the woofer. And a 18 liter enclouser tuned to 50hz.

Ouroboros · 4th February 2004, 08:25 AM

Actually you really need to measure the resonant frequency of the bass unit in its cabinet to determine the resonance compensation network. I've only ever done this for sealed box systems.

(Reflex loudspeakers are the work of the devil! (IMO of course)

Ouroboros · 4th February 2004, 08:42 AM

Oh Oh, I really should THINK before posting!

There's only an inductance compensating (Zobel) network on the bass unit. No resonance compensator!

!0r + 10u or 8R +12u aren't too much different in real life.

(I now go away and hang my head in shame)

sma · 4th February 2004, 10:06 AM

hi everybody,

how about inductor value for this HM170G8?assume use 18 litre box in 50hz.

So the zobel network is 10 mf + 10 ohm.I will try it.

2nd February 2004, 09:43 AM	#1
sma diyAudio Member Join Date: Dec 2003 Location: jakarta	Diy Audax Hi, i have 1 pair of audax HM170G8 and 1 pair of audax TW034XO tweeter.i interest for building 2 way loudspeaker,anyone have suggest about box size and crossover schematic for this configuration?

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2nd February 2004, 10:27 AM	#2
Taco diyAudio Member Join Date: Nov 2002 Location: Place in the Netherlands	I only know the HM170G8, and this woofer works perfectly in an 18 - 22 liter cabinet. With a F3 of about 50 hz. A simple first or second order x-over suffices.

2nd February 2004, 10:34 AM	#3
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	The TWO34 has its fundamental resonance below 900Hz, so it works well with a first-order crossover if you are setting the nominal crossover frequency to 3000Hz or so. It WILL need a series L_C_R network across it to compensate for the rise in impedance at resonance. (Otherwise you'll find that your high-pass filter isn't behaving as you expected it to). I use this tweeter myself with such a crossover with no problems. (If no-one responds with the resonance compensating network values, I'll check this evening with what I used and post it tomorrow). Chris Morriss.

3rd February 2004, 07:14 AM	#4
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	As a resonance compensating network, I use a series L-C-R network of 1.2mH, 33uF, 10R across the tweeter.

3rd February 2004, 07:58 PM	#5
sma diyAudio Member Join Date: Dec 2003 Location: jakarta	thank you ouroboros.i will try your schematic.. any one have suggest for woofer box?

4th February 2004, 07:17 AM	#6
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	To make a first order crossover work adequately, it would also be wise to place a network across the bass unit to compensate for the rise in impedance as the frequency increases. For the HM170G8, a series R-C network of 8.2R + 12uF is about right. The resonance compensating network across the tweeter, and the inductance compensating network across the bass unit means that the drive units now present a much more constant impedance load to the crossover. With these networks in place, you can then calculate the value of the series 'L' for the bass unit filter, and 'C' for the tweeter filter, assuming a constant 8R load. (It won't be perfect, but it will a LOT better than if the speaker impedance had not been compensated for.)

4th February 2004, 08:25 AM	#8
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	Actually you really need to measure the resonant frequency of the bass unit in its cabinet to determine the resonance compensation network. I've only ever done this for sealed box systems. (Reflex loudspeakers are the work of the devil! (IMO of course)

4th February 2004, 08:42 AM	#9
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	Oh Oh, I really should THINK before posting! There's only an inductance compensating (Zobel) network on the bass unit. No resonance compensator! !0r + 10u or 8R +12u aren't too much different in real life. (I now go away and hang my head in shame)

4th February 2004, 10:06 AM	#10
sma diyAudio Member Join Date: Dec 2003 Location: jakarta	hi everybody, how about inductor value for this HM170G8?assume use 18 litre box in 50hz. So the zobel network is 10 mf + 10 ohm.I will try it.