Trying to design my own speaker.

[bose301s 5,000+ posts]

I really would like to design my own set of speakers. I am looking at using the Vifa XT25TG30-04 Ring Radiator for the tweeter as I have heard good things about it and would like to try a ring radiator, and the Tang Band W6-1721 6-1/2" Underhung Midbass Driver for the woofer. I was wondering if these 2 drivers would mate up well with each other and what X-over frequency I should use, I was think 2kHz or so, but I would love suggestions from people who know more than me. Also, I would need a box design, would obviously like a compact bookshelf design. Any help will be greatly appreciated.

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[Millertime1028 10+ year member]

From looking at the parameters they should do well matched with eachother.. Crossover point should be around 2k on those .. Maybe a tad bit higher ..

 

[bose301s 5,000+ posts]

This is what I am thinking for the crossover:

I would use these parts then:

Solen 9.1uF 400V Poylpropylene Capacitor

Jantzen 0.60mH 20 AWG Air Core Inductor

 

[PV Audio 5,000+ posts]

Raise your x-over point up to 2500 or 2750. I would go so far as using the latter so that your tweeter doesn't suffer low frequency break up unless you decide to go with a Butterworth or Chebychev filter to get a little boost around the x-over point. That woofer has very clean upper frequency output, so you shouldn't worry about too much comb filtering (similar to standing waves, its basically a phenomenon where you get a signal reproducing rapidly but slightly out of phase so you get varying amounts of interference).

I also would not recommend starting with expensive drivers like that. In my experience, the best way to learn is to use cheap cones and try to make them sound as good as possible.

 

[bose301s 5,000+ posts]

Raise your x-over point up to 2500 or 2750. I would go so far as using the latter so that your tweeter doesn't suffer low frequency break up unless you decide to go with a Butterworth or Chebychev filter to get a little boost around the x-over point. That woofer has very clean upper frequency output, so you shouldn't worry about too much comb filtering (similar to standing waves, its basically a phenomenon where you get a signal reproducing rapidly but slightly out of phase so you get varying amounts of interference).
I also would not recommend starting with expensive drivers like that. In my experience, the best way to learn is to use cheap cones and try to make them sound as good as possible.

Well, I want a good sounding set of speakers, and I think these drivers would allow for that. I can always also buy some cheap stuff to tinker with. With a 2500Hz x-over I get very close to .5mH and 8uF, so I can get parts with values very close to those.

 

[PV Audio 5,000+ posts]

I would also highly recommend that you put some sort of fixed attenuation (whether it's an l-pad or a zobel network, or just a padding resistor) OR you go first order x-over with a solen -6db slope. I can see that tweet getting kinda fussy in relation to the mid.

 

[bose301s 5,000+ posts]

I would also highly recommend that you put some sort of fixed attenuation (whether it's an l-pad or a zobel network, or just a padding resistor) OR you go first order x-over with a solen -6db slope. I can see that tweet getting kinda fussy in relation to the mid.

I actually did an online chat with a guy from PE and he is going to send me a design PDF. Hopefully it will be an optimal set up.

Otherwise, could you explain to me what exactly you mean there. I am new to speaker building/design. I love having nice speakers, I mean my B&Ws are awesome, but that's all I have experience with, prebuilt stuff.

 

[PV Audio 5,000+ posts]

All attenuation means is lessening. A resistor works by opposing current, which is caused by a voltage drop between the ends of the resistor. Naturally, by rearranging ohms law, V=IR and P=IV can be re written into P=V^2/R. When you increase the resistance, it's easy to see that you get less power to the speaker, and therefore less output. This is helpful in speaker building when using bright or very efficient tweeters where you want to match the output of the tweeter to the midrange and woofer. By attenuating, or padding, you can get a far more seamless response.

An L-pad is a type of padding network. It actually stands for loss-pad which is how it works. It's used to effectively change the resistance of the speaker it's connected to which lessens its output in the frequency ranges where it matters (higher frequencies most often). They are connected to the crossover, one in parallel with the high pass circuit, and one in series with the low pass circuit. In essence, an l-pad cuts down on the tweeter's output which makes it flow better with the rest of the speaker.

A zobel network is a bit beyond my knowledge to explain, but I'll try. Basically, a zobel matches the speaker's impedance to make it easier to have a consistent ohm load sent to the amplifier. Note that zobels are NOT mainly audio circuits, but they are still used to attenuate different filters in crossovers. The way they work is by cutting a speaker's inductance at certain frequencies. Inductance in its most basic form is the resistance to a change in current.

The way it was explained to me is like this. Take a dam with water behind it and a water wheel in front of it of significant mass. The water starts flowing from the dam, and at first, the water is backed up while enough force builds to turn the wheel. After that, the speed evens out. When you go to close the dam, the same thing happens in reverse. That water wheel is resisting the change in current and as such, is storing the energy in the form of the water wheel turning. The inductor does the same by storing the circuit's current as an electromagnetic field that builds as long as the current is kept the same. At higher frequencies, more of that water can flow (thus more output). You then employ the zobel as a heavier water wheel to counter act that.

I know it's a bit daunting and I know it's confusing because I don't even understnad this **** well enough myself, so if anyone can clear that up, I'd appreciate it.

cliffs: You need to make the tweeter less loud

 

[PV Audio 5,000+ posts]

****, that was a beast of a post.

 

[bose301s 5,000+ posts]

All attenuation means is lessening. A resistor works by opposing current, which is caused by a voltage drop between the ends of the resistor. Naturally, by rearranging ohms law, V=IR and P=IV can be re written into P=V^2/R. When you increase the resistance, it's easy to see that you get less power to the speaker, and therefore less output. This is helpful in speaker building when using bright or very efficient tweeters where you want to match the output of the tweeter to the midrange and woofer. By attenuating, or padding, you can get a far more seamless response.
An L-pad is a type of padding network. It actually stands for loss-pad which is how it works. It's used to effectively change the resistance of the speaker it's connected to which lessens its output in the frequency ranges where it matters (higher frequencies most often). They are connected to the crossover, one in parallel with the high pass circuit, and one in series with the low pass circuit. In essence, an l-pad cuts down on the tweeter's output which makes it flow better with the rest of the speaker.

A zobel network is a bit beyond my knowledge to explain, but I'll try. Basically, a zobel matches the speaker's impedance to make it easier to have a consistent ohm load sent to the amplifier. Note that zobels are NOT mainly audio circuits, but they are still used to attenuate different filters in crossovers. The way they work is by cutting a speaker's inductance at certain frequencies. Inductance in its most basic form is the resistance to a change in current.

The way it was explained to me is like this. Take a dam with water behind it and a water wheel in front of it of significant mass. The water starts flowing from the dam, and at first, the water is backed up while enough force builds to turn the wheel. After that, the speed evens out. When you go to close the dam, the same thing happens in reverse. That water wheel is resisting the change in current and as such, is storing the energy in the form of the water wheel turning. The inductor does the same by storing the circuit's current as an electromagnetic field that builds as long as the current is kept the same. At higher frequencies, more of that water can flow (thus more output). You then employ the zobel as a heavier water wheel to counter act that.

I know it's a bit daunting and I know it's confusing because I don't even understnad this **** well enough myself, so if anyone can clear that up, I'd appreciate it.

cliffs: You need to make the tweeter less loud

I should have specified that you just needed to explain the LPad and Zobel network. I am an EE student, I know what resistors are and do quite well as well as Ohm's law and the various reformulations of it and power calculations //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Also, I know how caps and inductors work quite well too, but like I said, I didn't know what an lpad or Zobel network were. Just letting you know so that you can skip the easy stuff from here on out and get down to the technical stuff.

 

[PV Audio 5,000+ posts]

I thought that was you, but you changed your av so I wasn't sure //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

In that case, l-pads are just a set of resistors set after the tweeter but before the high pass filter that cut down on output. Zobels basically knock down impedance rise as a driver increases in frequency, and thus, a reduction in the high frequency reproduction.

Zobels are defined by the capacitance function, L / R^2. You pick a resistor with the same ohm rating as your speaker and the L is the driver's Le value. Connect the resistor and cap in series, then connect them in parallel to the driver after the cone but before the circuit.

 

[96civ 10+ year member]

Oh **** son, battle of the EE students.

 

[bose301s 5,000+ posts]

Oh **** son, battle of the EE students.

Lol, no. I know I have no clue speaker design, but I do know the basic components used in crossovers and stuff, just saying that so he didn't have to do the basics of resistors and stuff.

 

[bose301s 5,000+ posts]

Here are the designs they gave:

http://rapidshare.com/files/13835029...esign.zip.html

Sorry it's a RapidShare, but they used PDFs and I didn't know how else to do it.

 

[PV Audio 5,000+ posts]

Bad link son