Hi everyone,
This has always confused me,
if I will build a 3 way speaker box (i.e. woofer, midrange, tweeter and passive crossover), what is the common rule in choosing the wattage for them?
Let's say I have a 12" woofer with a nominal wattage of 200W, what wattage must the midrange and tweeter be? Should they all be equal?
A long time ago, I build a 3-way loudspeaker with a 100W woofer, 50W midrange, and 50W tweeter. Is this the right way to do it?
Thanks in advance!
JojoD
This has always confused me,
if I will build a 3 way speaker box (i.e. woofer, midrange, tweeter and passive crossover), what is the common rule in choosing the wattage for them?Let's say I have a 12" woofer with a nominal wattage of 200W, what wattage must the midrange and tweeter be? Should they all be equal?
A long time ago, I build a 3-way loudspeaker with a 100W woofer, 50W midrange, and 50W tweeter. Is this the right way to do it?
Thanks in advance!
JojoD
The wattage of a unit can mean many things ( there is many discussions on how to measure the power of a unit) but basically, the higher frequency units don't get as much power as the low frequency units.
The drivers don't need at all to have the same power handling capacity. For a normal (?!) room, with normal (???) pressure levels, 50 or 100 watt is more than enough if the crossover is correct.
In the case of a tweeter unit, I think that the excursion (X Max) is more problematic than power handling...
F
The drivers don't need at all to have the same power handling capacity. For a normal (?!) room, with normal (???) pressure levels, 50 or 100 watt is more than enough if the crossover is correct.
In the case of a tweeter unit, I think that the excursion (X Max) is more problematic than power handling...
F
navin said:
It varies with the kind of music, but 300 is the generally recognized average figure.
As to wattage, in most cases it is meaningless for most hifi purposes. You would like the woofer to be the least sensitive of the lot and if you can get sensitivities the same, then that is best (with the assumption that you are using a passive XO -- with an active XO it matters not)
dave
it depends dave on teh design.
given that BSC loss affects woofers and midbass most it pays to have them a bit more sens.
say you have a 90db tweeter and a 93db woofer you can apply a BSC ckt and still manage a speaker that is about 89db.
however if you have a 93db tweeter and a 90 db woofer then you have to fist BSC the woofer to about 86db or less and the pad the tweeter to 86db too.
yes 6db is more correct but note i assumed 4db BSC not 6db for above cases. 6db is too much compensation in most cases (unless you have 2 or more woofers) where you have the extra sensitivty. I try to keep the sens above 87db so one does not need 300W monoliths.
If the front bafffle is wider (say 0.34m to accomodate a 12") then teh BSC starts at 1000Hz and ends at 50Hz. However below 100hz room gain comes in too. so one does ot need to compensate for the last ocatve or so which I assume to be 2db.
given that BSC loss affects woofers and midbass most it pays to have them a bit more sens.
say you have a 90db tweeter and a 93db woofer you can apply a BSC ckt and still manage a speaker that is about 89db.
however if you have a 93db tweeter and a 90 db woofer then you have to fist BSC the woofer to about 86db or less and the pad the tweeter to 86db too.
yes 6db is more correct but note i assumed 4db BSC not 6db for above cases. 6db is too much compensation in most cases (unless you have 2 or more woofers) where you have the extra sensitivty. I try to keep the sens above 87db so one does not need 300W monoliths.
If the front bafffle is wider (say 0.34m to accomodate a 12") then teh BSC starts at 1000Hz and ends at 50Hz. However below 100hz room gain comes in too. so one does ot need to compensate for the last ocatve or so which I assume to be 2db.
jojo,
You need to understand that the "wattage" of a speaker, as Dave said, is practically meaningless. I've noticed a trend among many to use that so-called speaker rating as the determining factor in performance. Forget all of that! It tells you nothing about how the speaker (actually the driver) is going to react when it's inside a box (or outside). Probably the main information you'll want is the frequency response, the efficiency and the impedence. There's more but that's a start. I suggest you acquaint yourself with these terminologies by reading everything concerning speaker design you can get your hands on. About frequency response: different drivers cover different parts of the audio spectrum better than others, no two are the same. About efficiency (sensitivity): how many decibels will a driver produce when driven with one watt? It won't work well, necessarily, if one driver can produce 86db and another 92db in the same enclosure unless you compensate for that. About impedence: you probably don't want to use a 4 ohm driver in the same system with an 8 ohm driver. These are generalities but perhaps this gives you an idea about what it takes to design a speaker system. Three words, read, read, read.
You need to understand that the "wattage" of a speaker, as Dave said, is practically meaningless. I've noticed a trend among many to use that so-called speaker rating as the determining factor in performance. Forget all of that! It tells you nothing about how the speaker (actually the driver) is going to react when it's inside a box (or outside). Probably the main information you'll want is the frequency response, the efficiency and the impedence. There's more but that's a start. I suggest you acquaint yourself with these terminologies by reading everything concerning speaker design you can get your hands on. About frequency response: different drivers cover different parts of the audio spectrum better than others, no two are the same. About efficiency (sensitivity): how many decibels will a driver produce when driven with one watt? It won't work well, necessarily, if one driver can produce 86db and another 92db in the same enclosure unless you compensate for that. About impedence: you probably don't want to use a 4 ohm driver in the same system with an 8 ohm driver. These are generalities but perhaps this gives you an idea about what it takes to design a speaker system. Three words, read, read, read.
In Emiel's post he was talking about efficiencies, not power - tweeter usually more efficient.
A lot depends on crossover points and the relative power spectrum between each point. For your previous scenario of 100W woofer, then 50W midrange maybe a little large depending on where you cross the woofer, and what sort of music you listen to. If you used say 35W midrange then tweeter may only need to handle 10W, again depending on your crossover point - higher crossover frequency, lower power requirement.
As a bit of a guide, in pro audio concert PA, a 3-way system crossed at 250Hz and 1.2kHz usually runs mids = 3x tweeter power, subs = 3x mids power.
Cheers
You guys are right on the money, you have opened up my mind regarding the issue of speaker wattage. Ok, I'll forget that and look for the sensitivity of the drivers. I was invited to a showroom of a local speaker manufacturer and I'll be there on friday, at least now, I know what to look for and have the ability to listen to every part (woofer, midrange, tweeter) before I buy.
If you do have other words of wisdom, do's and dont's, I'll check up before I leave.
Best regards,
JojoD
If you do have other words of wisdom, do's and dont's, I'll check up before I leave.
Best regards,
JojoD
JoJo
Rod Elliot describes matching speaker levels on his site.
http://sound.westhost.com/index.html
Check out the article on Bi-amping.
http://sound.westhost.com/bi-amp.htm
Bob2
Rod Elliot describes matching speaker levels on his site.
http://sound.westhost.com/index.html
Check out the article on Bi-amping.
http://sound.westhost.com/bi-amp.htm
Bob2
planet10 said:
given that BSC is 6db there are few cases where the woofer is not less efficient than woofers. yes woofers should be less efficient after BSC because padding a woofer could serverly affect the bass response of the woofer.
BTW with bipoles do you only bipole the woofer or the tweeter as well.
i am going from my memory (this is from the late 60s early 70s i think i did more speaker building from 72-78 than i do now)...the way music spectrum is broken is as follows:
about 50% below 300hz
about 75% below 2500Hz
about 95% below 10k
I think then AR came out with the 2x, 2ax, 3x series they based the power handling of their drivers based on the above. These speakers used a large woofer in a sealed box.
A decade or so later the DQ10 was also similary designed.
todays music (electronic) has a lot more energy at the freq extremes so these % will change a bit) I used western classical music as my bench mark (read as Bach, Chopin, Liszt, Smethana, Beethoven, W.A Mozart etc...)
boy, now I have gone and dated myself
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