"Arny Krueger"

All you have to do is reduce distortion to the point where it is inaudible.
Easy enough to do in the 21st century - without active crossovers.

Still, you haven't give us one example of a low cost amplifier with no
audible distortion.



Staying within an $800 budget is not tough.

Two, low cost, stereo amplifiers: $400
Passive electronic crossover: $ 20
Two Vifa woofers at $100 each: $200
Two Vifa TG 27 tweeters at $30 each: $ 60
Two old enclosures from a garage sale: $ 20

Total: $ 700

This isn't a system.

Right, it isn't a system, it's the parts for a system. Add DIY and you
have a system.


IME, no. Either way, the best way is to optimize the driver & box
combination using Thiel/small parameters and verify with actual
measurements.

Most manufacturers of quality woofers provide T/S parameters and
leave the design up to the purchaser.

Manufactures give a "VB ltrs" spec. Isn't that the recommended box
volume?

Here's a sample set of data for a Vifa woofer from the manufacturer's web
site.

http://www.d-s-t.com/vifa/data/tc08sd49-04d.htm

Now maybe you can find Vb here, but I sure can't.

I have data sheets for Vifa woofers, that Madisound sent out. Each
data sheet *has* a recommended VB(Ltrs) for the woofer.

One can go to Google and type: "speaker calculator". It will come up
with Websites that offer free T/S box calculators. They are *very*
easy to use. Just type in four T/S parameters, and the calculator will
come up with the correct volume for the enclosure.


I can find Vas, but Vas isn't the same as recommended box size. Recommended
relationships between Vas, Vb and other parameters are given he

http://www.diysubwoofers.org/sld/sealed1.htm


Zoebels are for people who don't get it.

I'm one who doesn't "get it".

How do they relate to a system with an electronic crossover?


Zoebels are not necessary for an electronic crossover system. (One of
the *advantages* of electronic crossoves.)

BTW *You didn't answer the question.* What do you have against
Zoebels?


BTW#2 Here's how to calculate the Zoebel, R and C values:

Rz = 1.25 * R (the voice coil, dc resistance.)
Cz (in uF) = 1000 * L (in mH)/(Rz*Rz)


Example Calculation:

(The L and R values are from the Vifa P13WH-00-08, 5' woofer)

R dc voice coil = 5.7 and L voice coil inductance = 1 mH.

Rz = 5.7 * 1.25 = 7.1 Ohms
Cz = (1000 * 1) / (7.1 * 7.1)= 19.8 uF


Again, Rolling your own loudspeakers and getting good results is far from
simple unless you stick to subwoofers. Doing a two-way woofer/tweeter
speaker system *right* is actually one of the tougher technical chores
around.

Again, I have to disagree with you.

Yes, it is somewhat difficult to design a two-way speaker system: if
you want to have a bass reflex enclosure, if you want to have a
complex crossover (such as a 4th order, Linkwitz-Riley), if you want
to add equalization networks (to make the response flat to 1 dB), if
you want to have a resistive terminal impedance, and if you want to
have good polar patterns at all frequencies.

But, using a *closed box driver*, and using an *electronic crossover*,
greatly simplifies the design. Simplifies it to the point where, a
home builder can make a good two-way speaker, fairly easily.

Bob Stanton

"Bob-Stanton" wrote in message
om
"Arny Krueger"

All you have to do is reduce distortion to the point where it is
inaudible. Easy enough to do in the 21st century - without active
crossovers.

Still, you haven't give us one example of a low cost amplifier with no
audible distortion.

And you haven't given us one example of a low cost amplifier with audible
distoriton when operated within its ratings.

Staying within an $800 budget is not tough.

Two, low cost, stereo amplifiers: $400
Passive electronic crossover: $ 20
Two Vifa woofers at $100 each: $200
Two Vifa TG 27 tweeters at $30 each: $ 60
Two old enclosures from a garage sale: $ 20

Total: $ 700

This isn't a system.

Right, it isn't a system, it's the parts for a system. Add DIY and you
have a system.

Doooh. No front end, no control.

IME, no. Either way, the best way is to optimize the driver & box
combination using Thiel/small parameters and verify with actual
measurements.

Most manufacturers of quality woofers provide T/S parameters and
leave the design up to the purchaser.

Manufactures give a "VB ltrs" spec. Isn't that the recommended box
volume?

Here's a sample set of data for a Vifa woofer from the
manufacturer's web site.

http://www.d-s-t.com/vifa/data/tc08sd49-04d.htm

Now maybe you can find Vb here, but I sure can't.

I have data sheets for Vifa woofers, that Madisound sent out. Each
data sheet *has* a recommended VB(Ltrs) for the woofer.

One can go to Google and type: "speaker calculator". It will come up
with Websites that offer free T/S box calculators. They are *very*
easy to use. Just type in four T/S parameters, and the calculator will
come up with the correct volume for the enclosure.


I can find Vas, but Vas isn't the same as recommended box size.
Recommended relationships between Vas, Vb and other parameters are
given he

http://www.diysubwoofers.org/sld/sealed1.htm


Zoebels are for people who don't get it.

I'm one who doesn't "get it".

How do they relate to a system with an electronic crossover?

Zoebels are not necessary for an electronic crossover system. (One of
the *advantages* of electronic crossoves.)

BTW *You didn't answer the question.* What do you have against
Zoebels?

They add complexity and parts, when the problem they propose to solve can be
addressed by other means or not at all.

BTW#2 Here's how to calculate the Zoebel, R and C values:

Rz = 1.25 * R (the voice coil, dc resistance.)
Cz (in uF) = 1000 * L (in mH)/(Rz*Rz)


Example Calculation:

(The L and R values are from the Vifa P13WH-00-08, 5' woofer)

R dc voice coil = 5.7 and L voice coil inductance = 1 mH.

Rz = 5.7 * 1.25 = 7.1 Ohms
Cz = (1000 * 1) / (7.1 * 7.1)= 19.8 uF

Again, Rolling your own loudspeakers and getting good results is far
from simple unless you stick to subwoofers. Doing a two-way
woofer/tweeter speaker system *right* is actually one of the tougher
technical chores around.

Again, I have to disagree with you.

Yes, it is somewhat difficult to design a two-way speaker system: if
you want to have a bass reflex enclosure, if you want to have a
complex crossover (such as a 4th order, Linkwitz-Riley), if you want
to add equalization networks (to make the response flat to 1 dB), if
you want to have a resistive terminal impedance, and if you want to
have good polar patterns at all frequencies.

But, using a *closed box driver*, and using an *electronic crossover*,
greatly simplifies the design. Simplifies it to the point where, a
home builder can make a good two-way speaker, fairly easily.

I wish.

"Arny Krueger" wrote in message

And you haven't given us one example of a low cost amplifier with audible
distoriton when operated within its ratings.


How about any Radio Shack PA amplifier?


Doooh. No front end, no control.


Double doooh, and a duh. That wasn't asked for by the person who
started this thread.


I wish.

Me too. ;-)

Bob Stanton

"Bob-Stanton" wrote in message
om
"Arny Krueger" wrote in message

And you haven't given us one example of a low cost amplifier with
audible distortion when operated within its ratings.

How about any Radio Shack PA amplifier?

How about it. Where are your listening test results?

Doooh. No front end, no control.

Double doooh, and a duh. That wasn't asked for by the person who
started this thread.

That would be a matter of interpretation. Looks to me like he was looking
for a system for listening to music at home.