I am trying to design a baffle step compensation network for the woofers in my system. The calculations require the speaker Re, the DC resistance of the speaker voice coil. The published specs say this value is 6.7 ohms. My multimeter, with zeroed leads resistance, says the value is 6 .7 ohms. But my Dayton Audio DATS3 gave me a value of 8.98 ohms. They can't both be right, and using the different Re for the calculations gives me different values for the resistance and inductance of the circuit and for a zobel circuit across the woofer. Why am I getting different numbers, and which Re should I use?
If you don’t mind my curiosity, why does one need Re for a baffle step correction, apart from the situation one is simulating the bespoke drive unit? In that case one would need to know Le, Cm, Lm and Rm (at least) too.
The best way to do baffle step compensation is with the crossover and not with some cookbook formula. You are way better off using measurements and a crossover simulator like vituixcad with an optimixer to fit your measured woofer response to a target to automatically get your baffle step, usually with fewer parts.
For markbakk - The assumption is that the OP wants to do a parallel L-R filter between the crossover and amp using textbook / cookbook formulas. In practice these cookbook formulas give you an answer that may make you feel confident, but it isn't likely to give you good results.
For markbakk - The assumption is that the OP wants to do a parallel L-R filter between the crossover and amp using textbook / cookbook formulas. In practice these cookbook formulas give you an answer that may make you feel confident, but it isn't likely to give you good results.
And while for many here it is sacrelidge, using in room measurements imho yields more accurate results for the woofer as well
You mean impedance of course. But one can’t calculate a text book baffle step correction without extensive simulation of the sound field in a certain space around a certain loudspeaker enclosure. It’s next to pointless.
@eriksquires. I agree. What good does it do you if the network is optimized for close to calculated theoretically optimum conditions when the speaker will be used in a specifically flawed environment.
The range between 300 and 1k is critical to get right if you want a somewhat accurate sounding speaker.
The range between 300 and 1k is critical to get right if you want a somewhat accurate sounding speaker.
Maybe with a single inductor, you could get the 6db down where you want it, but as the z goes up, the response flattens out at 6db down the higher in freq you go instead of keep rolling off at 6db per octave…..
I wonder if that would sound bad….
I wonder if that would sound bad….
The single big inductor BSC trick works only so-so on a lot of baffles. I often end up using LCR branches.
I'd never expect a simple inductor to fulfill the BSC or EQ needs of such high end drivers. I'm already spending alot of money on these mids and don't intend to cheap out on passive filter components. That wouldn't make any sense.
My goals are pretty strict, aiming for at least +/- 1 dB in the mids. That may seem too ambitious for some of you, but the ear is very sensitive in the mids and capable of perceiving +/- 0.5 dB fluctuation. The lower mids need to be dialed in for the listening environment. I'm not looking for perfect FR in a anechoic conditions. Thats not where I'm listening. The lower mids are critical to perceived neutrality. They need to be on point. From just below 1k to 4k can be dialed in closer to desired response with just the midrange FR.
My goals are pretty strict, aiming for at least +/- 1 dB in the mids. That may seem too ambitious for some of you, but the ear is very sensitive in the mids and capable of perceiving +/- 0.5 dB fluctuation. The lower mids need to be dialed in for the listening environment. I'm not looking for perfect FR in a anechoic conditions. Thats not where I'm listening. The lower mids are critical to perceived neutrality. They need to be on point. From just below 1k to 4k can be dialed in closer to desired response with just the midrange FR.
Not at all. We can hear far less than that at some frequencies.. dependent on the system as a whole and it's state of tune, including the room.
For a 2 way system, with a 8 to 9 inch width, applied baffle step is typically 3 to 4 dB total, from around 200 - 250 Hz to 1600 - 2000 Hz. Theoretical full baffle step is 6 dB, but full application frequently gives a bass heavy sound, though it's sometimes applied. You are balancing direct and indirect sound for the best perceived compromise.
A dedicated baffle step correction (BSC) electrical circuit can be used, an inductor in parallel with a resistor placed in the woofer crossover. However, frequently the inductor inductance in the woofer crossover is just increased slightly for the necessary effect, so application of BSC is not readily evident from merely looking at the woofer crossover circuit. The crossover transfer function graph (electrical response) will show the effect of BSC. Looking at the non- compensated electrical response for the woofer, the voltage will be very close to flat from 200 Hz tp 1600 Hz. The woofer electrical response with baffle compensation will slope the voltage response in this same frequency region.
For a 3 dB total baffle compensation from 200 Hz to 1600 Hz:
Freq................Baffle Step Compensation Impact on the Woofer Crossover Response (Applied 3dB Total Over 3 Octaves, 1 dB per Octave)
200 Hz ......... - 0 dB
400 Hz .......... -1 dB
800 Hz ......... -2 dB
1600 Hz ....... -3 dB Total Compensation
After applying baffle step compensation, the tweeter level will need to be adjusted.
A dedicated baffle step correction (BSC) electrical circuit can be used, an inductor in parallel with a resistor placed in the woofer crossover. However, frequently the inductor inductance in the woofer crossover is just increased slightly for the necessary effect, so application of BSC is not readily evident from merely looking at the woofer crossover circuit. The crossover transfer function graph (electrical response) will show the effect of BSC. Looking at the non- compensated electrical response for the woofer, the voltage will be very close to flat from 200 Hz tp 1600 Hz. The woofer electrical response with baffle compensation will slope the voltage response in this same frequency region.
For a 3 dB total baffle compensation from 200 Hz to 1600 Hz:
Freq................Baffle Step Compensation Impact on the Woofer Crossover Response (Applied 3dB Total Over 3 Octaves, 1 dB per Octave)
200 Hz ......... - 0 dB
400 Hz .......... -1 dB
800 Hz ......... -2 dB
1600 Hz ....... -3 dB Total Compensation
After applying baffle step compensation, the tweeter level will need to be adjusted.
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