Any speaker design gurus?
12-09-2009, 05:06 PM
#31
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The other thing about low-order passive crossovers (i.e.; a single capacitor in series) is that they often do double duty as an equalization filter as well as acting in that crossover/LF protection role.
Imagine a tweeter that has a response with a big 12dB peak at the lower end of it's operating range, say 2KHz, that naturally slopes down to 0dB out at say 9KHz.
Placing a series cap tuned to 10K would flatten out that whole band so it matches the lower sensitivity and response of the mid or woofer.
Yes, you do lose efficiency on account of it, but it's going to sound a lot better than having all of that high-mid sensitivity blasting away- so just because the numbers seem screwy, doesn't mean things weren't done that way intentionally.
Nearly all of the systems I deal with are active crossovers, where we can separate the crossover function from the equalization, all of which takes place upstream from the amplifier channels, and we usually have lots of DSP or analog filters at our disposal.
Passive crossover design is considerably more of an art since the drivers themselves are not that easily mathematically modeled and passive components are far from ideal, so lots of compromises- and shall we say "creative" design approaches need to go into any passive crossover design.
Going the "parts express" route will require selecting drivers with matched sensitivity on top of all of the other things we've been discussing, not that it can't be done, but I still think it's going to be cheaper and easier to find a better off-the-shelf product.
Then again, if you want to get into speaker building as a hobby, you have nothing to lose but your time and money, which I think pretty much any hobby will relieve you of at some rate... and there are vast resources available out there for the hobbyist to help you get good results and not have to waste too much in the way of time or money
Imagine a tweeter that has a response with a big 12dB peak at the lower end of it's operating range, say 2KHz, that naturally slopes down to 0dB out at say 9KHz.
Placing a series cap tuned to 10K would flatten out that whole band so it matches the lower sensitivity and response of the mid or woofer.
Yes, you do lose efficiency on account of it, but it's going to sound a lot better than having all of that high-mid sensitivity blasting away- so just because the numbers seem screwy, doesn't mean things weren't done that way intentionally.
Nearly all of the systems I deal with are active crossovers, where we can separate the crossover function from the equalization, all of which takes place upstream from the amplifier channels, and we usually have lots of DSP or analog filters at our disposal.
Passive crossover design is considerably more of an art since the drivers themselves are not that easily mathematically modeled and passive components are far from ideal, so lots of compromises- and shall we say "creative" design approaches need to go into any passive crossover design.
Going the "parts express" route will require selecting drivers with matched sensitivity on top of all of the other things we've been discussing, not that it can't be done, but I still think it's going to be cheaper and easier to find a better off-the-shelf product.
Then again, if you want to get into speaker building as a hobby, you have nothing to lose but your time and money, which I think pretty much any hobby will relieve you of at some rate... and there are vast resources available out there for the hobbyist to help you get good results and not have to waste too much in the way of time or money
It's nice to know that I could be engineered this way, actually, the more I think about it I'm sure it was. It's simple in design, and works for the target consumer. It makes it easier to hit the target price point the company wants.
I don't want anyone to think I'm not happy as it is, I think for the money I have a lot of great sound.
It's a new interest I guess, but not one I want to go crazy on. I'll follow your and Matt's suggestion and just buy something that's ready to go in the future.
Thanks again guys, for all the help. I really appreciate it. I might've taken me weeks to figure all this out and you guys laid it down in a few posts!
12-10-2009, 12:31 AM
#32
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So just to be sure, is this what is happening:
Full Range audio goes from amp to each woofer. From the woofer it goes to either the tweeter or the mid driver. Does this mean the cap is like a High Pass filter? Does that also mean that the woofers are getting the upper range audio as well?
Full Range audio goes from amp to each woofer. From the woofer it goes to either the tweeter or the mid driver. Does this mean the cap is like a High Pass filter? Does that also mean that the woofers are getting the upper range audio as well?
12-10-2009, 08:33 AM
#33
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So just to be sure, is this what is happening:
Full Range audio goes from amp to each woofer. From the woofer it goes to either the tweeter or the mid driver. Does this mean the cap is like a High Pass filter? Does that also mean that the woofers are getting the upper range audio as well?
Full Range audio goes from amp to each woofer. From the woofer it goes to either the tweeter or the mid driver. Does this mean the cap is like a High Pass filter? Does that also mean that the woofers are getting the upper range audio as well?
The woofer will have it's own natural roll-off but the current drawn into the attached network of passive RCL parts including the mids and tweeters will be imposing a different roll-off, one more reason that it isn't so simple as just disconnecting each device and listening to what comes out.
Does this make sense?
(if not, I'm going to unsubscribe and leave you on your own to figure it out)
12-10-2009, 11:29 AM
#34
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Yes and no, remember these are circuits so you have series relationships (voltage division) and parallel (current division) the woofer is seeing full range voltage signal but the HF current will take the path of least resistance, so it will head over to the mid and tweeter accordingly
The woofer will have it's own natural roll-off but the current drawn into the attached network of passive RCL parts including the mids and tweeters will be imposing a different roll-off, one more reason that it isn't so simple as just disconnecting each device and listening to what comes out.
Does this make sense?
(if not, I'm going to unsubscribe and leave you on your own to figure it out)
The woofer will have it's own natural roll-off but the current drawn into the attached network of passive RCL parts including the mids and tweeters will be imposing a different roll-off, one more reason that it isn't so simple as just disconnecting each device and listening to what comes out.
Does this make sense?
(if not, I'm going to unsubscribe and leave you on your own to figure it out)
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