Somewhat confused with my speakers

[farookey]

Hi there, new to this forum....i have some questions and hopefully someone can help. i purchased two 10 pioneer woofers and 2 vifa tweeters along with a cross over to rebuild an old set of boxes. after hooking them up to an amplifier for the first time the highs seem to be unbearably overpowering! does anyone know what to do to eliminate this problem?

[spasticteapot]

Hi there, new to this forum....i have some questions and hopefully someone can help. i purchased two 10 pioneer woofers and 2 vifa tweeters along with a cross over to rebuild an old set of boxes. after hooking them up to an amplifier for the first time the highs seem to be unbearably overpowering! does anyone know what to do to eliminate this problem?

There should be two resistors in the tweeter section of the crossover: One in series, one in parallel. Increasing the value of the resistor in series might help a bit.

That said, generic crossovers don't work very well at all - design a crossover from scratch, or don't bother at all.

[Some Guy]

Hi there, new to this forum....i have some questions and hopefully someone can help. i purchased two 10 pioneer woofers and 2 vifa tweeters along with a cross over to rebuild an old set of boxes. after hooking them up to an amplifier for the first time the highs seem to be unbearably overpowering! does anyone know what to do to eliminate this problem?

Which Pioneer woofers? Which Vifa tweeters? What are you using for a corssover?

Basically sounds as though an L-pad may be in order...but maybe not.

[farookey]

Pioneer W25GR31-51F 10" woofer
Vifa D25AG-35 1" Aluminum Dome Tweeter
Crossover 2-Way 8 Ohm 5,000 Hz 150W

thats the setup i have going right now

[Æ]

Pioneer W25GR31-51F 10" woofer
Vifa D25AG-35 1" Aluminum Dome Tweeter
Crossover 2-Way 8 Ohm 5,000 Hz 150W

A 10 inch woofer doesn't have a lot of extended midrange. You probably have a bit of a midrange "hole" between the bass (woofer) and the tweeter (treble). You might want to modify your crossover to lower the tweeter crossover frequency about another octave. Typically if the tweeter is too hot, you would pad (attenuate) the tweeter to match the tweeter to the same level as the woofer. An adjustable L-Pad works fairly well.

[farookey]

so how about an L-pad for each tweeter along with an added resistor inline with the tweeter to lower the crossover frequency? Im really not sure how all of this works, kinda new to this stuff

[dthomas]

A 10 inch woofer will not play to 5000Hz and be considered high fidelity. At the most 1000Hz to 1500Hz and even then few woofers this size will do this. The tweeter you selected is best when used no lower than 2500Hz to 3000Hz. I would go as low as possible as the compromise on the tweeters performance will be negligible compared to the woofer above 1000Hz.

Your best option would be to buy a midrange dome like the RS52 and a 3 way crossover. But any premade crossover is not going to give you the expected response or deal with any of the drivers out of band anomalies.

An Lpad will help to tame your tweeter but you are likely hearing significant breakup from the woofer due to the high crossover point so it may not get you where you want to be or eliminate the screeching sound you hear. Also depending on your baffle width there will need to be some added baffle step compensation added to the crossover to get the overall response even reasonably flat.

The best advice I would give you is to scrap this idea and go with a kit if you are wanting a good sounding loudspeaker. No disrespect intended but what you are wanting to do is not going to net you a good soundling loudspeaker.
If you insist on trying to get this project off the ground see if PE will swap your crossover for a lower crossover frequency add an LPad and post your baffle dimension so someone here can recommend an inductor and resistor to at least some baffle step compensation to the crossover. You will need to be able to solder to add this circuit but it is pretty simple and straight forward to add.

A 10" 2 way loudspeaker is very difficult to accomplish and only a handful of drivers will even come close to pulling this off. And off the shelf crossovers are not the way to go if you are ultimately craving high fidelity.

[Dirk]

Now, don't actually DO this. It's more just a question:

Couldn't you effectively a.) cut the tweeter output by -3dB and b.) cut the crossover frequency in half by shunting the tweeter with 6-8ohm resistor?

I realize the impedance will be halved, but it'd only be for the high frequencies, and there's not really much power up there anyway. I don't think it'd give an average solid state amp any trouble.

Guys?

[farookey]

ok so what can i change in the crossover to lower the crossover frequency without returning the crossovers to parts express, is this possible? the speakers overall have a great sound, just a little bit of tweaking could help. does the fact the woofers being 8 ohms compared to the 6 ohm resistance of the tweeter?

[farookey]

the boxes are like 15x12x24ish tall

[johnastockman]

Pioneer W25GR31-51F 10" woofer
Vifa D25AG-35 1" Aluminum Dome Tweeter
Crossover 2-Way 8 Ohm 5,000 Hz 150W

thats the setup i have going right now

Yeah, that woofer will only be good up to 1000Hz to 1500Hz, at best. What you are hearing is the tweeter running full-bore (no l-pad to match up/attenuate its output to the woofer) and the woofer crossing WAY too high. It will sound horrible because the woofer just cannot physically reproduce frequencies that high and the cone will "break up" when feeding it the higher frequencies. Besides, a pre-made crossover (XO) isn't an option, as there are too many variables to consider...they can't take into account these things. They're designed for a fixed load of 4 or 8 ohms, which neither a woofer or a tweeter is. The pre-made assumes an "ideal" driver...never the case. And we know the old adage about "assume". I wish you would have asked before you spent your money on these. There are great projects out there in DIY speaker-land that net great sound quality for not alot of $$. You might be able to use those tweeters, but to get them to work properly and emit a sound you can listen to for more than one song without ear fatigue, you need a midrange to cover the "hole" in the midrange that the woofer just can't produce.

John A.

[philiparcario]

buy this amp


http://www.partsexpress.com/pe/showd...number=248-460

use it to run the tweeters, also buy a pair of these use these to cross to your tweeter

http://www.partsexpress.com/pe/showd...number=266-220

disconnect your tweeters from the crossover you have now and do the above one more thing buy two of these to hook up your current amp and the new amp

http://www.partsexpress.com/pe/showd...number=240-125

[farookey]

ok thanks for all this information and help, after listening closer, the tweeter is not overpowering, the 10 inch drivers are reproducing the higher notes but playing this a lot louder compared to the bass notes that are also present. i put alot of this into making these boxes look good, is a separate coaxial mid range on the side a good? Im thinking about getting the cross over lower for the driver and using a capacitor to cut off the low notes to the tweeter? any ideas from anyone?

[farookey]

Im wishing i didnt try to rebuild speakers, didnt think it would be this difficult.....but anyway, is it possible to unsolder a component in the crossover and replace with another to lower the frequency at which the speakers are cut off?

[donparsons]

Im wishing i didnt try to rebuild speakers, didnt think it would be this difficult.....but anyway, is it possible to unsolder a component in the crossover and replace with another to lower the frequency at which the speakers are cut off?

Let me try.

You have a Tuba and a picolo trying to play as an orchestra. Trying to get the picolo to sound like a trumpet by adding a resistor will not work. Trying to get the Tuba to sound like a clarinet by adding a coil and a cap won't work.

You are trying to make these speakers do things they are not capable of doing. Modifying a premade crossover is not the solution. If you worked hard to make the boxes nice, follow the advice of the very capable people who are giving you advice and try some other drivers and a custom crossover.

Trying to make these speakers work outside their range will either blow up the speakers, or worse your amp.

[dthomas]

Im wishing i didnt try to rebuild speakers, didnt think it would be this difficult.....but anyway, is it possible to unsolder a component in the crossover and replace with another to lower the frequency at which the speakers are cut off?

Get a 2.5mh low dcr inductor and a 4 ohm resistor. Parallel wire these two components together and place them in series with the input of your crossover.

This will roll off the highs but not the lows. Then let us know what you think. Also add an L pad to your tweeter so you can adjust the level.

Good luck,

[Some Guy]

Im wishing i didnt try to rebuild speakers, didnt think it would be this difficult...

It really isn't that difficult to get acceptable results. You do need to understand a few basic concepts but with just a little help, you can use off the shelf components to get something that will sound quite decent.

In this case, you've opted for a crossover frequency for your woofer that is too high by at least a factor of 2.5 so you need to get the crossover back down to 2KHz or so at a max. (A lot of folks will tell you that you can't run a 10 inch woofer that high but if you've ever listened to a pair of the old Large Advents or ADS L-620's, it is apparent that you can do it and get very good results.)

To use an "off the shelf" crossover, you will need to use something called an impedance compensation network (also called a Zobel) so that the load seen by the crossover is somewhere close to the load into which it was designed to work.

In this case, ballpark values for a woofer zobel to get you back to something close to an eight ohm load are going to be a capacitor of around 9-10 uf and a resistor of about 10 ohms connected together and then connected across the terminals of your woofer. No, these values are not exact and I am sure that if someone with the proper files for your drivers models these numbers, they will be off by at least 10 percent one way or the other. But the idea here is to get close.

(Parts Express has a crossover FAQ that may help you get an idea of what all this means.)

..but anyway, is it possible to unsolder a component in the crossover and replace with another to lower the frequency at which the speakers are cut off?

Sure. In this case you'll be replacing just about everything. Parts Express has a crossover component selection guide based on driver impedance, crossover slope and frequency that will give you "textbook values" for a simple crossover.

In this case with the Zobel network I mentioned, you'd design for a nominal 8 ohm impedance on your woofer. The tweeter you've chose is rated at a nominal 6 ohms and I'd say that isn't too far off from a value that you can use and get an acceptable result. If crossing at 2Khz, be sure to use a second order 12db/octave electrical filter to help protect the tweeter. You may also want to use an L-pad to adjust the level of the tweeter down a bit.

Don't give up. What you get will not be perfect but it can still be quite good.

[Some Guy]

Trying to make these speakers work outside their range will either blow up the speakers, or worse your amp.

Don't scare him off. The addiction hasn't set in yet.

To be fair about it, the woofer/tweeter combo he has is going to present a fairly easy load for just about any amp so I doubt there will be any amp blowage. Now he might fry a tweeter but that isn't the end of the world.

I'm thinking he can actually coax a pretty decent sounding two way out of this Pioneer 10 inch woofer (specs say the cone diameter is around 9 inches) and this Vifa tweeter. It won't be world class and it may not win any contests, but it should be at least in the range of "OK" with an xover somewhere in the 2 to 2.5Hz ballpark, even with textbook values (so long as he Zobels the woofer.) Lord knows that back in the 70's, I cobbled together much worse and was quite happy with it at the time.

[farookey]

thanks again for all the info, gotta read through and pick the best ideas

[farookey]

another question, i probably sound stupid but whatever, what is the difference between 6 and 12db crossovers?