Target Frequency Respons to design to

arc2v · 25th May 2007, 12:39 PM

Question about passive crossover design:

So you have your drivers, tweeter, and tools to model them:
What is your target SPL response?

I know it isn't flat -- that usually sounds boomy with a bit of shrill at 3kHz due to sensitivities of the ear.

Then there's room/baffle response. In my case, the open baffle will impart the dreaded S curve to the response at Feq.

So now I'm thinking I need to "invert" that S response for the baffle step (as much as possible). But again, the final target isn't flat.

What do you all design to? Or is it all test, rework, test, rework?

Thanks,
AC

bear · 25th May 2007, 03:02 PM

Wrt xover points, within reason "flat" at the xover is the nominal target.

Wrt overall response, that is a balancing act.
What you end up doing is making something that sounds good at the listening position, or sounds "correct" to the extent that you can make it so.

Most driver combinations have their own "characteristic sound" - one that is nearly impossible to overcome. The best you can do is correct the glaring parts and live with the rest.

In terms of overall balance, bass vs. highs - there is an old idea that one should roll the highs if the bass doesn't extend - and conversely. That seems to yield a balanced sound.

Then too, there is the issue of polar response especially of the tweeter and on-axis response vs. power response...

It's a compromise and balancing act.

_-_-Bear

arc2v · 29th May 2007, 12:38 PM

Thanks for the response.

Yeah, I understand the balancing act -- it's just that I do not have the budget to buy a dozen different crossovers worth of resistors, capacitors, and inductors to just fiddle with.

So I was hoping to come up with a design-to curve for the theoretical crossover and then tweak it from there to find the right balance of f3, efficiency, and overall flatness.

The more I learn about this, the more I see it's about crossover design. The only DIY stuff I've done in the past are kits (Adire HE 10.1's) and subwoofers (electronic crossovers) so I've never fiddled with this part of the build.

I am, however, really impressed with the FRD tools. Some good stuff there, almost too much for a beginner to deal with (but I'm a quick study).

Thanks again,
AC

25th May 2007, 12:39 PM	#1
arc2v diyAudio Member Join Date: May 2007	Target Frequency Respons to design to Question about passive crossover design: So you have your drivers, tweeter, and tools to model them: What is your target SPL response? I know it isn't flat -- that usually sounds boomy with a bit of shrill at 3kHz due to sensitivities of the ear. Then there's room/baffle response. In my case, the open baffle will impart the dreaded S curve to the response at Feq. So now I'm thinking I need to "invert" that S response for the baffle step (as much as possible). But again, the final target isn't flat. What do you all design to? Or is it all test, rework, test, rework? Thanks, AC

25th May 2007, 03:02 PM	#2
bear expert in tautology diyAudio Member Join Date: Apr 2002 Location: New York State USA	Wrt xover points, within reason "flat" at the xover is the nominal target. Wrt overall response, that is a balancing act. What you end up doing is making something that sounds good at the listening position, or sounds "correct" to the extent that you can make it so. Most driver combinations have their own "characteristic sound" - one that is nearly impossible to overcome. The best you can do is correct the glaring parts and live with the rest. In terms of overall balance, bass vs. highs - there is an old idea that one should roll the highs if the bass doesn't extend - and conversely. That seems to yield a balanced sound. Then too, there is the issue of polar response especially of the tweeter and on-axis response vs. power response... It's a compromise and balancing act. _-_-Bear __________________ _-_-bear http://www.bearlabs.com [...2SJ74 Toshiba bogus asian parts - beware! ] -- Btw, I don't actually know anything, FYI --

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29th May 2007, 12:38 PM	#3
arc2v diyAudio Member Join Date: May 2007	Thanks for the response. Yeah, I understand the balancing act -- it's just that I do not have the budget to buy a dozen different crossovers worth of resistors, capacitors, and inductors to just fiddle with. So I was hoping to come up with a design-to curve for the theoretical crossover and then tweak it from there to find the right balance of f3, efficiency, and overall flatness. The more I learn about this, the more I see it's about crossover design. The only DIY stuff I've done in the past are kits (Adire HE 10.1's) and subwoofers (electronic crossovers) so I've never fiddled with this part of the build. I am, however, really impressed with the FRD tools. Some good stuff there, almost too much for a beginner to deal with (but I'm a quick study). Thanks again, AC