hey guys i have a few questions i hope you can answer so i can better understand how crossovers work and how to choose or tune them.
im gathering information on how this all works before i start my first build for my soon to be new 5.1 home theater surround sound speakers. (i plan on making new speakers for everything but the subwoofer)
first question is on crossovers:
(hypothetical scenario) lets say i have a woofer that tops out at 1000hz and a tweeter that bottoms out at 800hz (just pulled those numbers out of nowhere) would i want to set the crossover at like 900hz so neither is hitting their limits? or is it better to set it for one of the limits and allow whichever speaker to hit its limit?
second question is on crossover type/sound quality:
(set up will be mainly used for movies and occasionally music but not nearly as often if that matters) am i going to get better quality sound and range from a woofer tweeter 2-way crossover set up? a woofer midrange and tweeter 3-way crossover set up? or like a pair of full range with no crossover at all?
third question is on impedance with crossovers:
my receiver is looking for an 8ohm load to be happy. i understand how to wire the different speakers (series/parallel) to reach that 8ohms that im looking for but i dont understand how it works once i add the crossover? i mean does it add to the impedance or subtract from it? does the receiver only see the woofer channel as impedance? does the crossover have its own impedance that the receiver sees and the speaker impedance is ignored at that point? i dont understand that and if someone could shed some light on that it would be amazing.
ok those are the three questions i have for now and i know that you guys know a lot more about this than i do. i just dont want to get all this stuff finally built after months of trying to learn about it just to turn it on and realize i majorly messed it all up and it sounds like garbage.
thanks ahead of time for your answers and help on this stuff.
im gathering information on how this all works before i start my first build for my soon to be new 5.1 home theater surround sound speakers. (i plan on making new speakers for everything but the subwoofer)
first question is on crossovers:
(hypothetical scenario) lets say i have a woofer that tops out at 1000hz and a tweeter that bottoms out at 800hz (just pulled those numbers out of nowhere) would i want to set the crossover at like 900hz so neither is hitting their limits? or is it better to set it for one of the limits and allow whichever speaker to hit its limit?
second question is on crossover type/sound quality:
(set up will be mainly used for movies and occasionally music but not nearly as often if that matters) am i going to get better quality sound and range from a woofer tweeter 2-way crossover set up? a woofer midrange and tweeter 3-way crossover set up? or like a pair of full range with no crossover at all?
third question is on impedance with crossovers:
my receiver is looking for an 8ohm load to be happy. i understand how to wire the different speakers (series/parallel) to reach that 8ohms that im looking for but i dont understand how it works once i add the crossover? i mean does it add to the impedance or subtract from it? does the receiver only see the woofer channel as impedance? does the crossover have its own impedance that the receiver sees and the speaker impedance is ignored at that point? i dont understand that and if someone could shed some light on that it would be amazing.
ok those are the three questions i have for now and i know that you guys know a lot more about this than i do. i just dont want to get all this stuff finally built after months of trying to learn about it just to turn it on and realize i majorly messed it all up and it sounds like garbage.
thanks ahead of time for your answers and help on this stuff.
1. Rather than just pull numbers out of nowhere, we would have to look at some real life woofer/tweeter specifications.
2. This really depends on personal choice and the quality of the drivers.
3. Basically, the receiver sees the impedance of the woofer. The frequency division provided by the crossover means that the woofer and tweeter are NOT simply combined as if they were in parallel.
2. This really depends on personal choice and the quality of the drivers.
3. Basically, the receiver sees the impedance of the woofer. The frequency division provided by the crossover means that the woofer and tweeter are NOT simply combined as if they were in parallel.
thank you for the feedback. the reason i just pulled the numbers out of nowhere is because i havent selected the drivers i want to use yet. i guess i can just pick a couple from parts express and use the specs from them. but that leads me to another question. which is is there more that i need to be looking at besides frequency range to determine where to set the crossover? and if so what else do i need to be looking at? my original question was basically is it a good idea to split the difference in the overlap of frequency range between the woofer and tweeter or do i need to be much more specific with where to set it?
1. For your example, yes you'd probably want to be in the middle. That should help in your selection of drivers, the more overlap the easier to work with and better chance they will integrate well.
2. Since you are going to use a subwoofer a 2-way should work fine. There is no "right" answer but a 2-way will likely be easier and cheaper.
3. As Galu points out it is not that simple. If you model the crossover in software you will be able to see the system impedance which is affected by the woofer, tweeter and crossover.
On the tech-talk forum at Parts Express there is a "sticky" at the top on Speaker Building Bible. Many of the links are no longer active but there is still a lot of good info. Check out Paul Carmody's FAQs linked there. If you don't plan to build more speakers in the future, building an existing "proven" design is often a good recommendation.
2. Since you are going to use a subwoofer a 2-way should work fine. There is no "right" answer but a 2-way will likely be easier and cheaper.
3. As Galu points out it is not that simple. If you model the crossover in software you will be able to see the system impedance which is affected by the woofer, tweeter and crossover.
On the tech-talk forum at Parts Express there is a "sticky" at the top on Speaker Building Bible. Many of the links are no longer active but there is still a lot of good info. Check out Paul Carmody's FAQs linked there. If you don't plan to build more speakers in the future, building an existing "proven" design is often a good recommendation.
what software would you recommend to use to design the crossover that would also tell me the end result impedance as well?
XSim free crossover designer seems to be popular with diyAudio members.
Download from: http://libinst.com/Xsim/XSimSetup.exe
Read about it here: XSim free crossover designer
Download from: http://libinst.com/Xsim/XSimSetup.exe
Read about it here: XSim free crossover designer
The receiver sees the woofer 8 ohms at low frequencies and the tweeter at the highs.
Although this depends, typically the main reason to not run a tweeter low is because it can't handle the workload. Apart from that it is (often) a good thing to cross low. Woofers have their upper frequency limit before they mess up the sound. The tweeters should sound fine running a little low in frequency, as long as you don't turn it up. You will learn your drivers as you use them when you find these limits.
1. a)The HF driver rule of thumb: keep the xo point a minimum of 1 octave above the resonance frequency (Fs), so 2 x Fs, but preferably 2 octaves above, so 4 x Fs. Can depend on the steepness of the xo slope and/or if you choose to use an resonance compensation filter in the xo (series LCR wired in parallel) and/or how loud they are meant to play.
b) The LF driver rule of thumb: keep the xo point below the frequency at which the frequency response 45 degrees off-axis falls below 3dB, altho in practice, the -6dB frequency is often accepted. This has to do with matching the directivity pattern of the 2 (or 3) drivers at the xo point.
c) Choose xo points that only let the best the drivers have to offer into the passband. Which means keep the xo point away from things like higher levels of distortion, resonances and cone breakup. See ZaphAudio's driver measurements as 1 example where you can see what driver distortion and resonances look like.
2. Generally to start, you want to choose 2nd or 4th order acoustic xo slopes. As a newby, pick the easier and cheaper one - 2nd order. Be aware tho that the electric order may be different, for eg 2nd order electric on the woofer and 3rd order electric on the tweeter are common for most simple 2-ways with 2nd order acoustic slopes. This has to do with matching phase at the xo points when both drivers are mounted on a flat baffle.
3. Listen to Allen B here, he is correct. so if you choose an 8ohm woofer and a 4ohm tweeter, nominally, you'll end up with a speaker closer to 4ohm than 8. Unless...... you've chosen a tweeter with much higher sensitivity and a fair amount of series resistance is used (say a minimum of 4 or 5ohms) to pad it down to the level of the woofer.
Also, choosing to use a xo program like XSim isn't quite that simple. At a minimum for a 2-way, you have to also use other program(s) to model baffle diffraction and baffle step loss, to combine those different FR's and to extract minimum phase for each driver's impedance before you are ready to load those files into a xo program. I haven't used it but I'm told that VituixCAD is a single program that pretty much has everything you need.
See also wintermute's excellent thread in the Stickies: So you want to design your own speakers from scratch.
Or.... you could start out with a proven design. I don't know what country you are in, but for your home theater purposes, it's hard to go wrong with Zaph's ZA5 family of speakers.
b) The LF driver rule of thumb: keep the xo point below the frequency at which the frequency response 45 degrees off-axis falls below 3dB, altho in practice, the -6dB frequency is often accepted. This has to do with matching the directivity pattern of the 2 (or 3) drivers at the xo point.
c) Choose xo points that only let the best the drivers have to offer into the passband. Which means keep the xo point away from things like higher levels of distortion, resonances and cone breakup. See ZaphAudio's driver measurements as 1 example where you can see what driver distortion and resonances look like.
2. Generally to start, you want to choose 2nd or 4th order acoustic xo slopes. As a newby, pick the easier and cheaper one - 2nd order. Be aware tho that the electric order may be different, for eg 2nd order electric on the woofer and 3rd order electric on the tweeter are common for most simple 2-ways with 2nd order acoustic slopes. This has to do with matching phase at the xo points when both drivers are mounted on a flat baffle.
3. Listen to Allen B here, he is correct. so if you choose an 8ohm woofer and a 4ohm tweeter, nominally, you'll end up with a speaker closer to 4ohm than 8. Unless...... you've chosen a tweeter with much higher sensitivity and a fair amount of series resistance is used (say a minimum of 4 or 5ohms) to pad it down to the level of the woofer.
Also, choosing to use a xo program like XSim isn't quite that simple. At a minimum for a 2-way, you have to also use other program(s) to model baffle diffraction and baffle step loss, to combine those different FR's and to extract minimum phase for each driver's impedance before you are ready to load those files into a xo program. I haven't used it but I'm told that VituixCAD is a single program that pretty much has everything you need.
See also wintermute's excellent thread in the Stickies: So you want to design your own speakers from scratch.
Or.... you could start out with a proven design. I don't know what country you are in, but for your home theater purposes, it's hard to go wrong with Zaph's ZA5 family of speakers.
Hey there, I have some 2 way designs in XSim available for free. Try your hand at removing the original crossover and designing your own.
A Speaker Maker's Journey: LM-1 Bookshelf Crossover
A Speaker Maker's Journey: LM-1 Bookshelf Crossover
thank you so much guys all this information and help has been amazing and super helpful to all my research before i start my first build. so again thank you all so much.
You don't have to build or design anything to "understand crossovers". One affordable and safe option is to study how components such as L, C, R, active filters, drivers and baffles/boxes work and compare that information to existing diy designs by more experienced. Some books are available, and internet is full of simplified examples and calculators able to visualize response and impedance changes when filter parameters or passive components are changed.
Practical option is to build some well-known diy kit and try to find answers how/why designer has ended up to those connections and component values. That also gives possibility to validate or even challenge the design with measurement gear and simulator. Or just study audibility of XO parameter changes. You also have speakers ready for use or tune for personal taste and/or individual environment.
Typical answer / recommendation for beginners is to start with the slowest and poorest methods and limited tools. Maybe the longest suffer, uncertain result and forced repeating is the most educative 😉
I prefer more objective and faster (=without iterative listening & tweaking methods) than "Designing crossovers without measurement". I would call it "Designing final crossover in few hours without listening a second". 'Few hours' includes also driver measurements. Adequate measurement gear, full-featured XO simulator and good knowledge about speaker+XO basics, measurements and measurable parameters of "an excellent loudspeaker" are needed of course. But this is just my perspective - without link or bias due to work with VituixCAD.
Practical option is to build some well-known diy kit and try to find answers how/why designer has ended up to those connections and component values. That also gives possibility to validate or even challenge the design with measurement gear and simulator. Or just study audibility of XO parameter changes. You also have speakers ready for use or tune for personal taste and/or individual environment.
Typical answer / recommendation for beginners is to start with the slowest and poorest methods and limited tools. Maybe the longest suffer, uncertain result and forced repeating is the most educative 😉
I prefer more objective and faster (=without iterative listening & tweaking methods) than "Designing crossovers without measurement". I would call it "Designing final crossover in few hours without listening a second". 'Few hours' includes also driver measurements. Adequate measurement gear, full-featured XO simulator and good knowledge about speaker+XO basics, measurements and measurable parameters of "an excellent loudspeaker" are needed of course. But this is just my perspective - without link or bias due to work with VituixCAD.