I'm sure this has been discussed here somewhere, but I haven't found it.
I'm designing some speakers for the first time. I hve some grasp on electronics, but I'm no expert. I will have 100W (RMS) going to the speaker. I'm thinking it's going to be a 3 way. I have a feeling that the tweeter won't need to handle as much wattage as the woofer. How do I figure out how much each component will recieve?
I'm designing some speakers for the first time. I hve some grasp on electronics, but I'm no expert. I will have 100W (RMS) going to the speaker. I'm thinking it's going to be a 3 way. I have a feeling that the tweeter won't need to handle as much wattage as the woofer. How do I figure out how much each component will recieve?
Hi HW,
save yourself a lot of headscratching and build this :
http://www.speakerbuilder.net/web_files/Projects/Lyra/lyramain.htm
P.S. its impossible to build a decent 3 way with simple 1st order c/o's.
/sreten.
save yourself a lot of headscratching and build this :
http://www.speakerbuilder.net/web_files/Projects/Lyra/lyramain.htm
P.S. its impossible to build a decent 3 way with simple 1st order c/o's.
/sreten.Well, let me explain my end goal.
I'd like a 3-way box with 5" woofers (possibly 5" mids for aesthetics) that will get me low enough to let a sub take over. These will be used for Home Theatre as well as musical reproduction. The room they will be in is quite small. I plan on building a box that will sit in a corner because there is no room to space them far enough for the side walls.
I want to design and build the main pair and hang them. Then, I'll make the sub, then add the center and rear pair. This is a long term project as I plan to learn a lot before pruchasing anything. I would like the best speakers possible, but (as always) price is a huge factor and must be kept lowish.
I appreciate any help. And like I said, I'd appreciate links to theory instead of a step by step build project.
Thanks
I'd like a 3-way box with 5" woofers (possibly 5" mids for aesthetics) that will get me low enough to let a sub take over. These will be used for Home Theatre as well as musical reproduction. The room they will be in is quite small. I plan on building a box that will sit in a corner because there is no room to space them far enough for the side walls.
I want to design and build the main pair and hang them. Then, I'll make the sub, then add the center and rear pair. This is a long term project as I plan to learn a lot before pruchasing anything. I would like the best speakers possible, but (as always) price is a huge factor and must be kept lowish.
I appreciate any help. And like I said, I'd appreciate links to theory instead of a step by step build project.
Thanks
HogieWan said:
He didn't say anything about range, he said it can't be done. That means regardless of range. I tend to agree, with some caveats. If you have never designed or built a two way, your chances with a 3 way are limited. Three ways can be difficult even with measurements and software....
HogieWan said:
Theoretical maximum (worst case) is 100W to each driver. Yet you could likely blow your mid or tweeter with a 10W amp
Power handling ratings are for chumps. Meaningless for the most part.....Manufacturers do not give you true or consistent ratings for tweeters and mids, and the woofer rating is a thermal rather than mechanical rating, so the rating gives you no useful info.
Pick a song and integrate the spectrum vs frequency to get the power distribution. The power distribution between drivers will change from song to song. The only way to know power distro if you are not an engineer and able to do the math, etc (and usually even if you are) is to increase the level until something breaks (statistically, as in more than once) and then apply a safety factor.
In a tongue in cheek rule of thumb manner, Pink noise is not a bad approximation to the spectrum of relentless heavy metal. Pink noise has equal power per octave. - so:
20-40=
40-80=
80-160=
160-320=
320-640=
640-1250=
1250-2500=
2500-5000=
5000-10000=
10000-20000
10 octaves, so 100/10=10 watts per octave (very roughly)
This seems to help, but doesn't really because first order crossovers are not brick walls and music is not pink noise. I have seen 1st order crossover systems where the tweeter and mid are pumping due to a Low frequency input.
BTW a 5" won't make it to subwoofer range and sound good. If you want any output from it at all at reasonably low distortion, you'll cross above 200Hz. If you have to go that high, why do a 3 way in the first place?
You can't make a 3-way 1st order system? Really?
Someone better tell Vandersteen, Thiel and Duntech .
I've never built a 2-way! For me, 3 way is the minimum for a hi-fi speaker with the ability to play sufficiently loud.
Generally power handling (thermal) is not a concern in a domestic situation. What's is far more important, especially for a first order system, is the displacement limited power handling in the low frequency range of each driver. 1st order crossover at 4kHz and above won't be an issue for most dome tweeters. For the woofers & mids, use Unibox which gives you a good idea of their excursion limits.
Regards
David
Someone better tell Vandersteen, Thiel and Duntech .
I've never built a 2-way! For me, 3 way is the minimum for a hi-fi speaker with the ability to play sufficiently loud.
Generally power handling (thermal) is not a concern in a domestic situation. What's is far more important, especially for a first order system, is the displacement limited power handling in the low frequency range of each driver. 1st order crossover at 4kHz and above won't be an issue for most dome tweeters. For the woofers & mids, use Unibox which gives you a good idea of their excursion limits.
Regards
David
Hi HW,
Some time ago I was wondering the same thing. I used to consider the music spectrum to be have similar power per octave as pink noise (-3dB/octave). But I found that this approximation was too bass heavy. In the absence of any hard data except for a very old AES article that measured SPL in a club situation, I decided to measure it for myself.
I did some tests on the spectra of popular music, including rock, pop, electronic, dance music. I chose these styles and omitted classical and jazz as I tend to listen to the popular styles at higher volumes and the purpose of the tests were to determine the relative maximum SPL's required across the frequency spectrum.
The results showed an almost exact -1.5dB/octave drop as frequency increased from about 45Hz to 10kHz. In the octave below 60Hz the amount of power dropped 12dB relative to the octave above it. In the octave above 10kHz the power dropped by 10dB relative to the octave below it.
Part of the drop in the top octave may be due to the nature of the source material which was all MP3 encoded.
You will also need to consider the sensitivities of the drivers and the crossover type in your calculations.
If you were to use brick-wall filters with infinite slopes then doing to calculations on power per band is easy. With other orders things are more complicated. You will need to consider the power delivered to the driver outside of the intended passband as well as within it. In the case of low order filters, the out of band power delievered to the driver in the octave below the crossover point may be greater than the power in the octave immediately above it which is within the passband!
A circuit simulator like pSpice or Microcap will allow you to model the crossover and determine the in and out of band power.
Interestingly, the lowest octave of 20-40Hz doesn't contain much power. Subwoofers for music can therefore be a bit smaller than might be expected. Indeed many people use only 10" drivers for subs.
One caveat might be the power required in the subwoofer region for use with movie soundtracks. These sometimes have a lot of low frequency energy. For movie use, a safe estimate might be to add 6-12dB to the power required for popular music.
Cheers,
Ralph
Some time ago I was wondering the same thing. I used to consider the music spectrum to be have similar power per octave as pink noise (-3dB/octave). But I found that this approximation was too bass heavy. In the absence of any hard data except for a very old AES article that measured SPL in a club situation, I decided to measure it for myself.
I did some tests on the spectra of popular music, including rock, pop, electronic, dance music. I chose these styles and omitted classical and jazz as I tend to listen to the popular styles at higher volumes and the purpose of the tests were to determine the relative maximum SPL's required across the frequency spectrum.
The results showed an almost exact -1.5dB/octave drop as frequency increased from about 45Hz to 10kHz. In the octave below 60Hz the amount of power dropped 12dB relative to the octave above it. In the octave above 10kHz the power dropped by 10dB relative to the octave below it.
Part of the drop in the top octave may be due to the nature of the source material which was all MP3 encoded.
You will also need to consider the sensitivities of the drivers and the crossover type in your calculations.
If you were to use brick-wall filters with infinite slopes then doing to calculations on power per band is easy. With other orders things are more complicated. You will need to consider the power delivered to the driver outside of the intended passband as well as within it. In the case of low order filters, the out of band power delievered to the driver in the octave below the crossover point may be greater than the power in the octave immediately above it which is within the passband!
A circuit simulator like pSpice or Microcap will allow you to model the crossover and determine the in and out of band power.
Interestingly, the lowest octave of 20-40Hz doesn't contain much power. Subwoofers for music can therefore be a bit smaller than might be expected. Indeed many people use only 10" drivers for subs.
One caveat might be the power required in the subwoofer region for use with movie soundtracks. These sometimes have a lot of low frequency energy. For movie use, a safe estimate might be to add 6-12dB to the power required for popular music.
Cheers,
Ralph
HogieWan said:
the power split depends on the crossover frequency.
here is a table to help you.
http://sound.westhost.com/bi-amp.htm
Thanks for all the help, guys. I'm starting to understand a bit more. I'm a Sys Admin and I seem to be doing my job correctly as I have a lot of reading time during the day. I probably won't even start looking for drivers until after the 1st of the year. I should have a better idea of a budget by then, also.
David Gatti said:
There are more components in their first order acoustic designs than you will find in most 4th order electricals designed by any gung ho newbie on this board.
Someone asking a question that makes no practical difference in speaker design isn't going to be successful without lots of luck.
The exception that proves the ruleDavid Gatti said:
I'm sure your stuff sounds like heaven and nirvana all rolled into a harem.- Status
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