Buidling my first speaker system but I have crossover questions

[m11a1]

Hi, I'm building my first speaker system and I'm really excited. I chose to use the Seas T25CF as the tweeter and the W15CY as the midwoofer.

1) How do I determine the optimal crossover frequency?
2) The T25CF has an impedance of 6 ohms while the W15CY has an impedance of 8 ohms, is this going to be a problem?

I have probably have more questions later.

Thanks!

[Pano]

Good questions!

1) The W15CY is small and will play high, so that gives you some leeway. My 1st guess would be about 2500Hz, 2nd order. Both drivers tend to naturally roll off around 2-2.5K, so that's a good starting point.

2) No. You just have to pick crossover parts to match the drivers.

I'm sure someone here has used these drivers to good effect, let's see if they chime in.

[BobEllis]

Crossover point is going to come down to a bit of personal preference, but I've got a system with the same drivers. The T25 has good distortion performance low, so you can cross it down between 1500 and 2000. LR2 electrical works great, add a deep notch at the woofer's breakup peak and pad the tweeter down a bit and you're set.

The Parts Express 3/8 cubic foot boxes are perfect for a ported application (or similar size). Even if you are going to cross to a sub, I suggest ported to keep the W15 excursion down. Bottom line - you'll be able to get louder cleaner with a ported alignment.

You'll get a very nice system when done properly with these drivers. You will definitely hear the difference between amplifiers. Give them a good amp and you will be rewarded.

In a big room, you will want to turn them into a three way with a bass bin running up to 150-300 Hz, but that can be a second project. Mine are actively crossed at 160 Hz LR4 and the max SPL limit is my desire to maintain my hearing.

[m11a1]

Thanks guys!

After been away busy working on my crossover design I have come across another question.

For example, if my crossover design calls for a capacitor of 1.8 uF, is it critical that I have to have exactly 1.8 uF or can I use a 1.75 uF capacitor?

Thanks again

[giralfino]

0.05 uF of difference for a 1.8 uF cap is less than 3%.
Normal caps, and good ones too, have often a 2-5% tolerance, so from a practical point of view, 1.75 and 1.8 uF caps are equivalent.

IMHO it should be easy to find a 1.8 uF cap, as this value is a standard one.

Ralf

[m11a1]

Thanks!

But, how about inductors and resistors? Do they follow the same concept? Do they also have a tolerance?

The reason I'm asking these questions is because I'm trying to lessen the mess of parallels and series of capacitors, inductors, and resistors that I have.

[sreten]

Hi,

For your first build just copy something done with your preferred driver
by someone who knows what they are doing and wonder about the
why's and wherefore's as you build it, it makes far more sense.

Monitor W15NeoSEAS W15CY001 +

W15CY001-OWI

Zaph|Audio : indicates a problem issue to be taken seriously.

You may have a lot more fun building this first off :
Zaph|Audio - ZMV5 - MCM / Vifa 5" System

(Note the w15 won't resolve the bass level issues much, its driver size related.)

rgds, sreten.

http://sites.google.com/site/undefinition/diy
http://www.zaphaudio.com
http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://www.rjbaudio.com/
http://speakerdesignworks.com/
http://www.htguide.com/forum/showthread.php4?t=28655
http://www.humblehomemadehifi.com
http://www.troelsgravesen.dk/Diy_Lou...r_Projects.htm
http://www.quarter-wave.com/
http://www.frugal-horn.com/
http://www.linkwitzlab.com/
http://www.musicanddesign.com/

[giralfino]

But, how about inductors and resistors? Do they follow the same concept? Do they also have a tolerance?

Everything produced has a tolerance. Resistors come mainly with 1, 2 and 5% tolerance. For inductors, apart the tolerance factor, there is the possibility to have any value you need, simply buying a larger value and unwind the wire (and measure).

Ralf

[giralfino]

For your first build just copy something done with your preferred driver
by someone who knows what they are doing and wonder about the
why's and wherefore's as you build it, it makes far more sense.

I can agree on that, but the fun in building our own design is IMHO more rewarding. The problem is that the possibility to do something wrong is high, and choosing to do the first build with expensive drivers is not a good idea.

If you choose to design your speaker, sreten has provided you with some good links. Fortunately there is free software for design (look at FRD tools), and a good mic doesn't cost an arm and a leg.

Ralf

[sreten]

Hi,

IMO its no fun realising after the fact (of the build), there is more to it than
you first thought, and that is why the speakers (expensive drivers or not),
do not sound as good as you expected, but it is your / anyones choice.

Expensive drivers (when there are so many better value drivers) is not
the way to start. Work your way up to it. People will buy any good
jobs you do on the way just to have something bespoke / original.

rgds, sreten.