hey guys. i have decided to build my own crossovers and know to parts i need. I just wanted to know what to do. I have a 4 ohm woofer and a 4 ohm tweeter. I went to a online calculator and got all the parts to do it(not yet ordered). The thing is that my amp is 8 ohms and i got 2, 4 ohm speakers that i have ran in series. I just wanted to know what will happen to my impedance once i hook up the parts to cross it over. The crossover design is a 2nd order linkwitz-riley.
2nd Order Linkwitz-Riley
4000 Hertz
4 Ohm Tweeter / 4 Ohm Woofer
Parts List
Capacitors
C1 = 4.98 uF
C2 = 4.98 uF
Inductors
L1 = 0.32 mH
L2 = 0.32 mH
4000 Hertz
4 Ohm Tweeter / 4 Ohm Woofer
Parts List
Capacitors
C1 = 4.98 uF
C2 = 4.98 uF
Inductors
L1 = 0.32 mH
L2 = 0.32 mH
An externally hosted image should be here but it was not working when we last tested it.
Ok. The amp says ''use 8 ohms''. It have 2 channels that are non-bridgable. I have built some cabinets with 1 tweeter which is 4 ohms and 1 woofer that is also 4 ohms. I plan to wire those in series and go into the amp. But i want to cross it over. its just that i dont know how to run the crossovers in series. (refer to pic).
There are series crossovers, but that still doesn't get you a safe load for an 8 ohm load only amp. A better solution would be to would be to add another woofer and wire them in series. Your 8 ohm amp can handle a 4 ohm tweeter properly crossed because it won't be delivering a lot of power to the tweeter, especially if crossed fairly high.
How did you calculate your crossover components? Do the driver sensitivities match? Are you planning to measure the driver responses in your cabinet and design the crossover from there?
Textbook crossovers generally don't work well because they assume a constant driver impedance and flat response a couple octaves outside the passband. Take a look at the spec sheet and you'll see that this probably isn't true. Better to plug the published frequency responses and impedance curves into a simulator. There are free/free demos available, such as ARTA, Basta and Speaker Workshop. You'll get mush better simulations and results if you measure the drivers responses in your boxes, though.
How did you calculate your crossover components? Do the driver sensitivities match? Are you planning to measure the driver responses in your cabinet and design the crossover from there?
Textbook crossovers generally don't work well because they assume a constant driver impedance and flat response a couple octaves outside the passband. Take a look at the spec sheet and you'll see that this probably isn't true. Better to plug the published frequency responses and impedance curves into a simulator. There are free/free demos available, such as ARTA, Basta and Speaker Workshop. You'll get mush better simulations and results if you measure the drivers responses in your boxes, though.
Tested how? Without a crossover?
At low volume 4 ohm impedance won't be an issue. Often an amp rated 8 ohms minimum has minimal heat sinking. This becomes an issue at high powers when the output stage is dissipating more heat. If you use a series crossover, the effect is to short out the tweeter for low frequencies and short the woofer for highs. You still end up with a roughly 4 ohm nominal impedance and may run into issues as you crank it up.
It would help to know what drivers you are using and links to any known data sheets. Box dimensions and layout? Any goals for the system other than not blow up your amp?
GOOD crossovers are designed for a particular set of drivers on a particular baffle placed in a particular position in the room. You may have been happy with the random crossover that you used but a properly designed crossover will work much better if you prefer flat frequency and power response.
At low volume 4 ohm impedance won't be an issue. Often an amp rated 8 ohms minimum has minimal heat sinking. This becomes an issue at high powers when the output stage is dissipating more heat. If you use a series crossover, the effect is to short out the tweeter for low frequencies and short the woofer for highs. You still end up with a roughly 4 ohm nominal impedance and may run into issues as you crank it up.
It would help to know what drivers you are using and links to any known data sheets. Box dimensions and layout? Any goals for the system other than not blow up your amp?
GOOD crossovers are designed for a particular set of drivers on a particular baffle placed in a particular position in the room. You may have been happy with the random crossover that you used but a properly designed crossover will work much better if you prefer flat frequency and power response.
Ok. Lets start from the beginning. It would be great if you can help me design this. The tweeter im using is a JBL 035Ti. It is 4 ohms and the frequency response is 2khz to 20khz. This is taken right from the JBL website. The woofer is and MTX audio TR4512-04. Its 4 ohms and the frequency resopnce is 35hz to 150hz. I have built the MTX spec ported box for the woofer and the tweeter has its own box attached to the top of it. if you need andthing else, just tell me.
-Thanks
-Thanks
OK, so you have a car subwoofer and an obsolete tweeter and want to make a speaker system out of it? Too bad you didn't get the TR4512-44, you could have wired the voice coils in series and had an 8 ohm woofer.
The TR4512-04 really shouldn't be used above 100 Hz. If you were happy with this driver combination crossed at 800 Hz or 4500 Hz, why not just use that?
The Tweeter may be usable down to 2KHz. Please post a link to the datasheet or attach the datasheet. I couldn't find it on JBL or JBLPro.
What kind of midrange/midwoofer do you have?
What crossover did you use?
Is this for home or car use?
We're talking a three way for a first design project. Not a good idea. Better to get an easy to use 6-7" woofer to work with and make a two way. Later you can figure out how to cross that to the MTX at around 100 Hz.
Links to external sources make it easier for someone to help you. I dont have an inclination to determine what an MTX recommended box is, much less search for driver specifications that would let me model the woofer to determine if that tuning is suitable for home use.
The TR4512-04 really shouldn't be used above 100 Hz. If you were happy with this driver combination crossed at 800 Hz or 4500 Hz, why not just use that?
The Tweeter may be usable down to 2KHz. Please post a link to the datasheet or attach the datasheet. I couldn't find it on JBL or JBLPro.
What kind of midrange/midwoofer do you have?
What crossover did you use?
Is this for home or car use?
We're talking a three way for a first design project. Not a good idea. Better to get an easy to use 6-7" woofer to work with and make a two way. Later you can figure out how to cross that to the MTX at around 100 Hz.
Links to external sources make it easier for someone to help you. I dont have an inclination to determine what an MTX recommended box is, much less search for driver specifications that would let me model the woofer to determine if that tuning is suitable for home use.
Ok. First off i know, i wanted to get the TR4512-44, but i got the wrong one. Anyway, i went to crossover designer for a 2 way crossover and i asked for what frequency i want. So should i put it at 800hz or 4500hz? The link for the tweeter.
http://manuals.harman.com/JBL/HOM/Technical Sheet/L80T ts.pdf
The tweeter is out of a JBL L80T.
I do have a midrange, but i have a two seperate channels for them so its not even worth talking about those.
The crossover i USED is also from a JBL L80-T
It is for my room.
Here is the woofer spec sheet...
http://shop.mtx.com/support/Download/1843/TR4512-04.pdf
I sure hope this helps.
http://manuals.harman.com/JBL/HOM/Technical Sheet/L80T ts.pdf
The tweeter is out of a JBL L80T.
I do have a midrange, but i have a two seperate channels for them so its not even worth talking about those.
The crossover i USED is also from a JBL L80-T
It is for my room.
Here is the woofer spec sheet...
http://shop.mtx.com/support/Download/1843/TR4512-04.pdf
I sure hope this helps.
Well, that MTX "data sheet" tells a conscientious designer nothing. Probably designed for a boomy one note bass response in a car.
About the only useful information in the JBL manual is that the DC resistance of the tweeter coil has a loose tolerance, and the actual impedance is probably 5-6 ohms.
What amps(s) do you have available? Link to specifications?
About the only useful information in the JBL manual is that the DC resistance of the tweeter coil has a loose tolerance, and the actual impedance is probably 5-6 ohms.
What in the world do you mean by that? You must use a midrange to make a useable system out of the other two drivers, you must talk about it and use appropriate filtering on all drivers. Are you saying that you have another amp which you want to use to drive the midrange? Active crossovers are an option - Mid/tweet on one with a passive XO between them and the other for the woofer.
What amps(s) do you have available? Link to specifications?
This is my amp. I know its a mini hifi And probabally not that good, but its mine and i dont have alot of money. Plus im 15 years old.
This is the back of it. The red and black terminals are the normal terminals. The blue and grey terminals are what i mean by "for the mids". I have tested them and put out vocals very good.
And since im new to this whole crossover thing. Please go easy on me with complicated stuff.
-Very much appreciated.
OK, this can be a problem.
Are the blue outputs supposed to be for surround speakers?
Often the mini systems throw in some bass boost to make up for the crummy drivers in their speakers. So you have a voltmeter? We'll want to measure the frequency response of the mini system to see if it is flat enough to be useful.
Again, what is your mid?
Do you have two MTX woofers?
What is your budget for this project?
What are your goals for this project?
Are the blue outputs supposed to be for surround speakers?
Often the mini systems throw in some bass boost to make up for the crummy drivers in their speakers. So you have a voltmeter? We'll want to measure the frequency response of the mini system to see if it is flat enough to be useful.
Again, what is your mid?
Do you have two MTX woofers?
What is your budget for this project?
What are your goals for this project?
Yes i have a voltmeter. Again me being new, how would you measure frequency response?
Yes i have two MTX woofers and two seperate cabinets.
My budget for the crossover parts and such is anything under 50 dollars for both cabinets.
My goals are to make this work by running the speakers in series or any other way of making the final impedance into the amp around 8 ohms.
-Thanks for your time.
Yes i have two MTX woofers and two seperate cabinets.
My budget for the crossover parts and such is anything under 50 dollars for both cabinets.
My goals are to make this work by running the speakers in series or any other way of making the final impedance into the amp around 8 ohms.
-Thanks for your time.
Didn't we go thru all this back before Christmas?
http://www.diyaudio.com/forums/multi-way/179103-crossover-help.html
http://www.diyaudio.com/forums/multi-way/179103-crossover-help.html
Aah, missed that.
You need a different amp to handle the low impedance loads. $50 isn't enough of a budget to do much with, anyway.
Until you can save up a bit more, just hook it up the way that you though sounded good and keep the volume low enough that your amp doesn't go into protect mode. Keep an eye out at garage sales and on the curb for a real amplifier.
You need a different amp to handle the low impedance loads. $50 isn't enough of a budget to do much with, anyway.
Until you can save up a bit more, just hook it up the way that you though sounded good and keep the volume low enough that your amp doesn't go into protect mode. Keep an eye out at garage sales and on the curb for a real amplifier.
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